WorldWideScience

Sample records for inshore squid loligo

  1. Gear Selectivity of a Longfin Squid Bottom Trawl

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Loligo pealeii (longfin inshore squid) co-occurs with Atlantic butterfish (Peprilus triacanthus) throughout the year and discarding in the L. pealeii bottom trawl...

  2. The biomass and ecology of chokka squid Loligo vulgaris reynaudii ...

    African Journals Online (AJOL)

    Migration, stock size and ecology of chokka squid Loligo vulgaris reynaudii off the West Coast of South Africa were studied and their relationship to other regions compared by analysis of distributional, biomass, and size composition, and biological data collected from biannual research cruises from 1983-1987. Biomass ...

  3. Differential expression of the FMRF gene in adult and hatchling stellate ganglia of the squid Loligo pealei

    NARCIS (Netherlands)

    Burbach, J.P.H.; Grant, P.; Hellemons, A.J.C.G.; DeGiorgis, J.A.; Li, K.W.; Pant, H.C.

    2014-01-01

    The giant fiber system of the squid Loligo pealei mediates the escape response and is an important neurobiological model. Here, we identified an abundant transcript in the stellate ganglion (SG) that encodes a FMRFamide precursor, and characterized FMRFamide and FI/LRF-amide peptides. To determine

  4. Cadmium content in fresh and canned squid (Loligo opalescens) from the Pacific coastal waters of California (USA).

    Science.gov (United States)

    Galitsopoulou, A; Georgantelis, D; Kontominas, M G

    2009-01-01

    Cadmium (Cd) levels were determined in 70 samples of mantle tissue and 70 whole individual squid (Loligo opalescens; commercially known as California squid). Samples were collected from the coastal zones of California (USA) during the period 2007/2008. To further investigate consumer exposure to processed fishery products, cadmium concentration was also determined in 200 canned samples of squid. Cd concentrations in raw mantle were low, between 0.01 and 0.29 mg kg(-1) and below the tolerance limit of current regulations (1 mg kg(-1)). Respective concentrations in whole individuals were significantly higher, ranging from 0.51 to 1.18 mg kg(-1), attributed to the presence of the visceral portion in whole squid samples. Cd concentrations varied in relation to age and sex of squid, indicating that several physiological factors may influence accumulation. Furthermore, canning of squid substantially enhanced Cd levels. Cd concentration ranged 0.17-0.67 mg kg(-1) in canned mantle tissue and 0.86-2.07 mg kg(-1) in canned whole squid samples, due to both concentration after canning and movement of the metal between different tissues. Several biological compounds, including metallothioneins, nucleic acids and enzymes, may affect Cd concentrations in commercial fishery products.

  5. Habitat and distribution of post-recruit life stages of the squid Loligo forbesii

    Science.gov (United States)

    Smith, Jennifer M.; Macleod, Colin D.; Valavanis, Vasilis; Hastie, Lee; Valinassab, Tooraj; Bailey, Nick; Santos, M. Begoña; Pierce, Graham J.

    2013-10-01

    This study models habitat preferences of the squid Loligo forbesii through its post-recruitment life cycle in waters around Scotland (UK). Trawl survey and market sample data from 1985 to 2004 are used to model seasonal habitats of immature, maturing and mature squid (maturity being inferred from size and season). Squid presence-absence and catch rate in areas of presence were analysed using generalised additive models, relating spatiotemporal patterns of distribution and abundance to ecogeographic variables. For all maturity classes, higher abundance in winter and spring (i.e., quarters 1 and 2) was associated with deeper water while higher abundance in summer and autumn (quarters 3 and 4) was associated with shallower water, consistent with seasonal onshore-offshore migrations but suggesting that most spawning may take place in deeper waters. The preferred SST range was generally 8-8.75 °C while preferred salinity values were below 35‰ in winter and summer and above 35‰ in spring and autumn. Squid were positively associated with gravel substrate and negatively associated with mud. Seasonal changes in habitat use were more clearly evident than changes related to inferred maturity, although the two effects cannot be fully separated due to the annual life cycle. Habitat selection for this species can be satisfactorily modelled on a seasonal basis; predictions based on such models could be useful for fishers to target the species more effectively, and could assist managers wishing to protect spawning grounds. The extent to which this approach may be useful for other cephalopods is discussed.

  6. Intense Ultrasonic clicks from echolocating toothed whales do not elicit anti-predator responses or debilitate the squid Loligo pealeii

    DEFF Research Database (Denmark)

    Wilson, Maria; Hanlon, Roger; Tyack, Peter

    2007-01-01

    an evolutionary selection pressure on cephalopods to develop a mechanism for detecting and evading sound-emitting toothed whale predators. Ultrasonic detection has evolved in some insects to avoid echolocating bats, and it can be hypothesized that cephalopods might have evolved similar ultrasound detection...... as an anti-predation measure. We test this hypothesis in the squid Loligo pealeii in a playback experiment using intense echolocation clicks from two squid-eating toothed whale species. Twelve squid were exposed to clicks at two repetition rates (16 and 125 clicks per second) with received sound pressure...... levels of 199-226dBre1μPa (pp) mimicking the sound exposure from an echolocating toothed whale as it approaches and captures prey. We demonstrate that intense ultrasonic clicks do not elicit any detectable anti-predator behaviour in L. pealeii and that clicks with received levels up to 226dBre1μPa (pp...

  7. Differential impacts of ocean acidification and warming on winter and summer progeny of a coastal squid (Loligo vulgaris).

    Science.gov (United States)

    Rosa, Rui; Trübenbach, Katja; Pimentel, Marta S; Boavida-Portugal, Joana; Faleiro, Filipa; Baptista, Miguel; Dionísio, Gisela; Calado, Ricardo; Pörtner, Hans O; Repolho, Tiago

    2014-02-15

    Little is known about the capacity of early life stages to undergo hypercapnic and thermal acclimation under the future scenarios of ocean acidification and warming. Here, we investigated a comprehensive set of biological responses to these climate change-related variables (2°C above winter and summer average spawning temperatures and ΔpH=0.5 units) during the early ontogeny of the squid Loligo vulgaris. Embryo survival rates ranged from 92% to 96% under present-day temperature (13-17°C) and pH (8.0) scenarios. Yet, ocean acidification (pH 7.5) and summer warming (19°C) led to a significant drop in the survival rates of summer embryos (47%, Pocean acidification and summer warming scenarios. The occurrence of prolonged embryogenesis along with lowered thermal tolerance limits under such conditions is expected to negatively affect the survival success of squid early life stages during the summer spawning period, but not winter spawning.

  8. The mechanics of locomotion in the squid Loligo pealei: locomotory function and unsteady hydrodynamics of the jet and intramantle pressure.

    Science.gov (United States)

    Anderson, E J; DeMont, M E

    2000-09-01

    High-speed, high-resolution digital video recordings of swimming squid (Loligo pealei) were acquired. These recordings were used to determine very accurate swimming kinematics, body deformations and mantle cavity volume. The time-varying squid profile was digitized automatically from the acquired swimming sequences. Mantle cavity volume flow rates were determined under the assumption of axisymmetry and the condition of incompressibility. The data were then used to calculate jet velocity, jet thrust and intramantle pressure, including unsteady effects. Because of the accurate measurements of volume flow rate, the standard use of estimated discharge coefficients was avoided. Equations for jet and whole-cycle propulsive efficiency were developed, including a general equation incorporating unsteady effects. Squid were observed to eject up to 94 % of their intramantle working fluid at relatively high swimming speeds. As a result, the standard use of the so-called large-reservoir approximation in the determination of intramantle pressure by the Bernoulli equation leads to significant errors in calculating intramantle pressure from jet velocity and vice versa. The failure of this approximation in squid locomotion also implies that pressure variation throughout the mantle cannot be ignored. In addition, the unsteady terms of the Bernoulli equation and the momentum equation proved to be significant to the determination of intramantle pressure and jet thrust. Equations of propulsive efficiency derived for squid did not resemble Froude efficiency. Instead, they resembled the equation of rocket motor propulsive efficiency. The Froude equation was found to underestimate the propulsive efficiency of the jet period of the squid locomotory cycle and to overestimate whole-cycle propulsive efficiency when compared with efficiencies calculated from equations derived with the squid locomotory apparatus in mind. The equations for squid propulsive efficiency reveal that the refill

  9. Multiple Mating, Paternity and Complex Fertilisation Patterns in the Chokka Squid Loligo reynaudii.

    Directory of Open Access Journals (Sweden)

    Marie-Jose Naud

    Full Text Available Polyandry is widespread and influences patterns of sexual selection, with implications for sexual conflict over mating. Assessing sperm precedence patterns is a first step towards understanding sperm competition within a female and elucidating the roles of male- and female-controlled factors. In this study behavioural field data and genetic data were combined to investigate polyandry in the chokka squid Loligo reynaudii. Microsatellite DNA-based paternity analysis revealed multiple paternity to be the norm, with 79% of broods sired by at least two males. Genetic data also determined that the male who was guarding the female at the moment of sampling was a sire in 81% of the families tested, highlighting mate guarding as a successful male tactic with postcopulatory benefits linked to sperm deposition site giving privileged access to extruded egg strings. As females lay multiple eggs in capsules (egg strings wherein their position is not altered during maturation it is possible to describe the spatial / temporal sequence of fertilisation / sperm precedence There were four different patterns of fertilisation found among the tested egg strings: 1 unique sire; 2 dominant sire, with one or more rare sires; 3 randomly mixed paternity (two or more sires; and 4 a distinct switch in paternity occurring along the egg string. The latter pattern cannot be explained by a random use of stored sperm, and suggests postcopulatory female sperm choice. Collectively the data indicate multiple levels of male- and female-controlled influences on sperm precedence, and highlights squid as interesting models to study the interplay between sexual and natural selection.

  10. Phylogenetic characterization of epibiotic bacteria in the accessory nidamental gland and egg capsules of the squid Loligo pealei (Cephalopoda:Loliginidae).

    Science.gov (United States)

    Barbieri, E; Paster, B J; Hughes, D; Zurek, L; Moser, D P; Teske, A; Sogin, M L

    2001-03-01

    Sexually mature female squid Loligo pealei harbour dense bacterial communities in their accessory nidamental glands (ANGs) and in their egg capsules (ECs). This study describes a molecular approach using the 16S rRNA gene (rDNA) to identify bacterial populations within the ANG and the ECs of the North Atlantic squid species L. pealei. Fluorescent in situ hybridization (FISH) and 16S rDNA analysis showed that predominantly alpha- and, to a lesser extent, gamma-proteobacteria were the predominant components of the ANG and EC bacterial communities. Sequencing results showed the presence of alpha-proteobacterial populations affiliated with the Roseobacter group and additional deep-branching alpha-proteobacterial lineages. In contrast, isolates from the ANG and ECs contained only a few alpha-proteobacteria of the Roseobacter group compared with several gamma-proteobacterial isolates, mostly Shewanella and Pseudoalteromonas species. Most of the ANG-associated bacterial populations were also found within the ECs of L. pealei. The molecular approach allowed the visualization of alpha-proteobacteria as major constituents of a bacterial symbiosis within the reproductive system of the Loliginidae.

  11. The South African chokka squid Loligo vulgaris reynaudii is caught ...

    African Journals Online (AJOL)

    spamer

    during the 1970s and early 1980s that official statistics started to reveal ... a South African offshore component fishing off both .... 2: Annual landings of Loligo vulgaris reynaudii, 1971–1997, by the trawl fishery, both South African and foreign ...

  12. The impact of environmental gradients on the early life inshore ...

    African Journals Online (AJOL)

    The impact of environmental gradients on the early life inshore migration of the short-finned squid Illex illecebrosus. JAA Perez, Rk O'dor. Abstract. Recruitment of the short-finned squid Illex illecebrosus to adult feeding grounds on the shelf off eastern Canada constitutes an important transition from warm food-limited Gulf ...

  13. Antibacterial Activity of Melanin from Cuttlefish and Squid Ink

    Directory of Open Access Journals (Sweden)

    Yuspihana Fitrial

    2017-08-01

    Full Text Available Marine environment comprises of many organism which are known to posses bioactive compound as a common means of self-defense or for the protection of eggs and embryos. Class Cephalopods (such as squidand cuttlefish are notable for their defences, such as jetting escape movements, changes in colouration, toxic venom and inking.This study aims to compare the antibacterial activity of melanin from cuttlefish ink (Sepia sp. with squid ink (Loligo sp. against E. coli. Extraction and purification studies were carried out on Sepia and Loligo melanin using a hydrochloric acid 0,5M treatment under mechanical.The melanins were obtained and further evaluated their activity by direct contact methods between melanin and E. coli in nutrient broth.Total microbes was counted by total plate count.Both inks also was tested their activity against E. coli. The results showed that melanin from cuttlefish and squid inks had inhibitory activity at concentrations of 10 mg / ml and 20 mg / mL, respectively reaching 99.99% against E. coli.The inks of both Cephalopods at the same concentration as melanin, did not show any inhibitory activity against E. coli.  The melanin of Sepia sp. have a higher antibacterial activity than the melanin of Loligo sp.

  14. Chromatographic Characterization and GC-MS Evaluation of the Bioactive Constituents with Antimicrobial Potential from the Pigmented Ink of Loligo duvauceli

    OpenAIRE

    Girija, Smiline; Duraipandiyan, Veeramuthu; Kuppusamy, Pandi Suba; Gajendran, Hariprasad; Rajagopal, Raghuraman

    2014-01-01

    Chromatographic characterization and the GC-MS evaluation of the black pigmented ink of Loligo duvauceli in the present study have yielded an array of bioactive compounds with potent antimicrobial property. Facing an alarm of antimicrobial resistance globally, a need for elucidating antimicrobial agents from natural sources will be the need for the hour. In this view, this study is aimed at characterizing the black pigmented ink of the Indian squid L. duvauceli. The squid ink was subjected to...

  15. Forecasting chokka squid Loligo vulgaris reynaudii catches and ...

    African Journals Online (AJOL)

    spamer

    2017-11-11

    Nov 11, 2017 ... on ambient water temperature (Augustyn et al. 1992,. A. Oosthuisen, University of ..... from tagged squid and the supply of continuous environ- mental data. ... should a leak develop, and to provide insulation for the electronics.

  16. Integrative omics analysis reveals differentially distributed proteins in dimorphic euspermatozoa of the squid, Loligo bleekeri.

    Science.gov (United States)

    Yoshida, Masa-aki; Yamada, Lixy; Ochi, Hiroe; Iwata, Yoko; Tamura-Nakano, Miwa; Sawada, Hitoshi; Sauer, Warwick H H; Ogura, Atsushi; Hirohashi, Noritaka

    2014-08-01

    In the coastal squid Loligo bleekeri, each male produces one of two types of fertilization-competent spermatozoa (eusperm) that exhibit morphological and behavioral differences. Large "consort" males produce short-tailed spermatozoa that display free-swimming behavior when ejaculated into seawater. Small "sneaker" males, on the other hand, produce long-tailed spermatozoa that exhibit a self-swarming trait after ejaculation. To understand the molecular basis for adaptive traits employed by alternative male mating tactics, we performed the transcriptome deep sequencing (RNA-seq) and proteome analyses to search for differences in testicular mRNAs and sperm proteins, respectively. From mature male testes we identified a total of 236,455 contigs (FPKM ≧1) where 3789 and 2789 were preferentially (≧10-fold) expressed in consort and sneaker testes, respectively. A proteomic analysis detected 4302 proteins in the mature sperm as post-translational products. A strongly biased (≧10-fold) distribution occurred in 55 consort proteins and 61 sneaker proteins. There was no clear mRNA-protein correlation, making a ballpark estimate impossible for not only overall protein abundance but also the degree of biased sperm type expressed in the spermatozoa. A family encoding dynein heavy chain gene, however, was found to be biased towards sneakers, whereas many enzymes involving energy metabolism were heavily biased towards consort spermatozoa. The difference in flagellar length matched exactly the different amount of tubulins. From these results we hypothesize that discrete differential traits in dimorphic eusperm arose from a series of innovative alterations in the intracellular components of spermatozoa. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Commercial squids: characterization, assessment of potential health benefits/risks and discrimination based on mineral, lipid and vitamin E concentrations.

    Science.gov (United States)

    Torrinha, A; Gomes, F; Oliveira, M; Cruz, R; Mendes, E; Delerue-Matos, C; Casal, S; Morais, S

    2014-05-01

    The most consumed squid species worldwide were characterized regarding their concentrations of minerals, fatty acids, cholesterol and vitamin E. Interspecific comparisons were assessed among species and geographical origin. The health benefits derived from squid consumption were assessed based on daily minerals intake and on nutritional lipid quality indexes. Squids contribute significantly to daily intake of several macro (Na, K, Mg and P) and micronutrients (Cu, Zn and Ni). Despite their low fat concentration, they are rich in long-chain omega-3 fatty acids, particularly docosahexaenoic (DHA) and eicosapentanoic (EPA) acids, with highly favorable ω-3/ω-6 ratios (from 5.7 to 17.7), reducing the significance of their high cholesterol concentration (140-549 mg/100g ww). Assessment of potential health risks based on minerals intake, non-carcinogenic and carcinogenic risks indicated that Loligo gahi (from Atlantic Ocean), Loligo opalescens (from Pacific Ocean) and Loligo duvaucelii (from Indic Ocean) should be eaten with moderation due to the high concentrations of Cu and/or Cd. Canonical discriminant analysis identified the major fatty acids (C14:0, C18:0, C18:1, C18:3ω-3, C20:4ω-6 and C22:5ω-6), P, K, Cu and vitamin E as chemical discriminators for the selected species. These elements and compounds exhibited the potential to prove authenticity of the commercially relevant squid species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Ultrastructural damage of Loligo vulgaris and Illex coindetii statocysts after low frequency sound exposure.

    Directory of Open Access Journals (Sweden)

    Marta Solé

    Full Text Available There is a considerable lack of information concerning marine invertebrate sensitivity to sound exposure. However, recent findings on cuttlefish and octopi showed that exposure to artificial noise had a direct consequence on the functionality and physiology of the statocysts, sensory organs, which are responsible for their equilibrium and movements in the water column. Owing to a lack of available data on deep diving cephalopod species, we conducted a noise exposure comparative experiment on one Mediterranean squid, Illex coindetii, and on the European squid Loligo vulgaris. Scanning electron microscopy (SEM revealed similar injuries in the inner structure of the statocysts, as those found in cuttlefish and octopi. In addition to the ultrastructural description of the lesions, we publish here the first images of the crista-cupula system and inner statocyst cavity of I. coindetii.

  19. spawning grounds for chokka squid Loligo vulgaris reynaudii, using

    African Journals Online (AJOL)

    denise

    Swimming movements in relation to egg beds have been studied using acoustic micro-electronic transmitters implanted in squid and tracked via 3-D radio-linked acoustic positioning telemetry (O'Dor et al. 1996, 1998, Sauer et al. 1997). Most of these methods are either impractical or would be severely limited on the deeper ...

  20. Differential expression of the FMRF gene in adult and hatchling stellate ganglia of the squid Loligo pealei

    Directory of Open Access Journals (Sweden)

    J. Peter H. Burbach

    2013-12-01

    The giant fiber system of the squid Loligo pealei mediates the escape response and is an important neurobiological model. Here, we identified an abundant transcript in the stellate ganglion (SG that encodes a FMRFamide precursor, and characterized FMRFamide and FI/LRF-amide peptides. To determine whether FMRFamide plays a role in the adult and hatchling giant fiber system, we studied the expression of the Fmrf gene and FMRFamide peptides. In stage 29 embryos and stage 30 hatchlings, Ffmr transcripts and FMRFamide peptide were low to undetectable in the SG, in contrast to groups of neurons intensely expressing the Fmrf gene in several brain lobes, including those that innervate the SG. In the adult SG the Fmrf gene was highly expressed, but the FMRFamide peptide was in low abundance. Intense staining for FMRFamide in the adult SG was confined to microneurons and fibers in the neuropil and to small fibers surrounding giant axons in stellar nerves. This shows that the Fmrf gene in the SG is strongly regulated post-hatching, and suggests that the FMRFamide precursor is incompletely processed in the adult SG. The data suggest that the SG only employs the Fmrf gene post-hatching and restricts the biosynthesis of FMRFamide, demonstrating that this peptide is not a major transmitter of the giant fiber system. This contrasts with brain lobes that engage FMRFamide embryonically as a regulatory peptide in multiple neuronal systems, including the afferent fibers that innervate the SG. The biological significance of these mechanisms may be to generate diversity within Fmrf-expressing systems in cephalopods.

  1. Therapeutic Significance of Loligo vulgaris (Lamarck, 1798) ink Extract: A Biomedical Approach

    Science.gov (United States)

    Nadarajah, Sri Kumaran; Vijayaraj, Radha; Mani, Jayaprakashvel

    2017-01-01

    Background: The squid ink extract is well known for its biomedical properties. Objective: In this study, squid Loligo vulgaris was collected from Tuticorin costal water, Bay of Bengal, India. Materials and Methods: Proximate composition of the crude squid ink was studied and found to have protein as the major component over lipid and carbohydrates. Further, bioactive fractions of squid ink were extracted with ethanol, and therapeutic applications such as hemolytic, antioxidant, antimicrobial, and in vitro anti-inflammatory properties were analyzed using standard methods. Results: In hemolytic assay, the squid ink extract exhibited a maximum hemolytic activity of 128 hemolytic unit against tested erythrocytes. In DPPH assay, the ethanolic extract of squid ink has exhibited an antioxidant activity of 83.5%. The squid ink was found to be potent antibacterial agent against the pathogens tested. 200 μL of L. vulgaris ink extract showed remarkable antibacterial activity as zone of inhibition against Escherichia coli (28 mm), Klebsiella pneumoniae (22 mm), Pseudomonas aeruginosa (21 mm), and Staphylococcus aureus (24 mm). The 68.9% inhibition of protein denaturation by the squid ink extract indicated that it has very good in vitro anti-inflammatory properties. The Fourier transform infrared spectroscopy analysis of the ethanolic extracts of the squid ink indicated the presence of functional groups such as 1° and 2° amines, amides, alkynes (terminal), alkenes, aldehydes, nitriles, alkanes, aliphatic amines, carboxylic acids, and alkyl halides, which complements the biochemical background of therapeutic applications. Conclusion: Hence, results of this study concluded that the ethanolic extract of L. vulgaris has many therapeutic applications such as antimicrobial, antioxidant, and anti-inflammatory activities. SUMMARY Squid ink is very high in a number of important nutrients. It’s particularly high in antioxidants for instance, which as well all know help to protect

  2. Antibacterial Activity of Melanin from Cuttlefish and Squid Ink

    OpenAIRE

    Yuspihana Fitrial; Iin Khusnul Khotimah

    2017-01-01

    Marine environment comprises of many organism which are known to posses bioactive compound as a common means of self-defense or for the protection of eggs and embryos. Class Cephalopods (such as squidand cuttlefish) are notable for their defences, such as jetting escape movements, changes in colouration, toxic venom and inking.This study aims to compare the antibacterial activity of melanin from cuttlefish ink (Sepia sp.) with squid ink (Loligo sp.) against E. coli. Extraction and purificatio...

  3. 76 FR 40012 - Semiannual Agenda of Regulations

    Science.gov (United States)

    2011-07-07

    ... Endangered Leatherback Sea Turtle. 100 Critical Habitat 0648-AX50 Designation for Cook Inlet Beluga Whale... mackerel, Loligo squid, Illex squid, and butterfish (including gear impacts on Loligo squid egg EFH); and...

  4. 75 FR 79725 - Fall 2010 Semiannual Agenda of Regulations

    Science.gov (United States)

    2010-12-20

    ... Leatherback Sea 0648-AX06 Turtle 265 Critical Habitat Designation for Cook Inlet Beluga Whale Under the... mackerel, Loligo squid, Illex squid, and butterfish (including gear impacts on Loligo squid egg EFH); and...

  5. Effects of ocean acidification on trace element accumulation in the early-life stages of squid Loligo vulgaris

    International Nuclear Information System (INIS)

    Lacoue-Labarthe, T.; Reveillac, E.; Oberhaensli, F.; Teyssie, J.L.; Jeffree, R.; Gattuso, J.P.

    2011-01-01

    Highlights: → We study radiotracer uptake in squid embryo and paralarvae under relevant pCO 2 . → We examine metal distribution and concentration factors in egg compartments. → Increasing pCO 2 affects eggshell shielding properties and metal uptake in animals. → Chemical signature in statoliths is modified by higher Zn incorporation under high pCO 2 . → Both element chemical properties and embryo physiology could account for the observed effects. - Abstract: The anthropogenic release of carbon dioxide (CO 2 ) into the atmosphere leads to an increase in the CO 2 partial pressure (pCO 2 ) in the ocean, which may reach 950 μatm by the end of the 21st century. The resulting hypercapnia (high pCO 2 ) and decreasing pH ('ocean acidification') are expected to have appreciable effects on water-breathing organisms, especially on their early-life stages. For organisms like squid that lay their eggs in coastal areas where the embryo and then paralarva are also exposed to metal contamination, there is a need for information on how ocean acidification may influence trace element bioaccumulation during their development. In this study, we investigated the effects of enhanced levels of pCO 2 (380, 850 and 1500 μatm corresponding to pH T of 8.1, 7.85 and 7.60) on the accumulation of dissolved 110m Ag, 109 Cd, 57 Co, 203 Hg, 54 Mn and 65 Zn radiotracers in the whole egg strand and in the different compartments of the egg of Loligo vulgaris during the embryonic development and also in hatchlings during their first days of paralarval life. Retention properties of the eggshell for 110m Ag, 203 Hg and 65 Zn were affected by the pCO 2 treatments. In the embryo, increasing seawater pCO 2 enhanced the uptake of both 110m Ag and 65 Zn while 203 Hg showed a minimum concentration factor (CF) at the intermediate pCO 2 . 65 Zn incorporation in statoliths also increased with increasing pCO 2 . Conversely, uptake of 109 Cd and 54 Mn in the embryo decreased as a function of increasing

  6. 75 FR 70192 - Fisheries of the Northeastern United States; Summer Flounder, Scup, and Black Sea Bass Fisheries...

    Science.gov (United States)

    2010-11-17

    ... squid, butterfish, and Atlantic bluefish fisheries. If the total amount of RSA is not awarded, NMFS will...; 727,527 lb (330 mt) of Loligo squid; 818,790 lb (371 mt) of bluefish; and 33,069 lb (15 mt) of... stock assessment data for summer flounder, scup, black sea bass, Loligo squid, butterfish, bluefish...

  7. Chromatographic Characterization and GC-MS Evaluation of the Bioactive Constituents with Antimicrobial Potential from the Pigmented Ink of Loligo duvauceli.

    Science.gov (United States)

    Girija, Smiline; Duraipandiyan, Veeramuthu; Kuppusamy, Pandi Suba; Gajendran, Hariprasad; Rajagopal, Raghuraman

    2014-01-01

    Chromatographic characterization and the GC-MS evaluation of the black pigmented ink of Loligo duvauceli in the present study have yielded an array of bioactive compounds with potent antimicrobial property. Facing an alarm of antimicrobial resistance globally, a need for elucidating antimicrobial agents from natural sources will be the need for the hour. In this view, this study is aimed at characterizing the black pigmented ink of the Indian squid L. duvauceli. The squid ink was subjected to crude solvent extraction and was fractionated by silica gel column chromatography. TLC and HPTLC profiles were recorded. Antimicrobial bioassay of the squid ink fractions was done by agar well diffusion method. The antimicrobial fraction was then characterized using GC-MS analysis. The results showed that the n-hexane extract upon column fractionation yielded a total of 8 fractions with the mobile phase of Hex/EtOAc in different gradients. TLC and HPTLC profiles showed a single spot with a retention factor of 0.76. Fraction 1 showed significant antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Lactobacillus acidophilus and a promising antifungal activity against Candida albicans. The antimicrobial fraction upon GC-MS analysis of bis(2-ethylhexyl) phthalate (BEHP) possesses the highest percentage of area normalisation (91%) with other few minor constituents. The study is concluded by stating that the antimicrobial efficacy of the squid ink might be due to the synergistic effects of the phthalate derivative and the other minor volatile compounds analysed in the squid ink.

  8. Effects of ocean acidification on trace element accumulation in the early-life stages of squid Loligo vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Lacoue-Labarthe, T., E-mail: tlacouel@gmail.com [INSU-CNRS, Laboratoire d' Oceanographie de Villefranche, B.P. 28, 06234 Villefranche-sur-mer Cedex (France); International Atomic Energy Agency - Environment Laboratories, 4 Quai Antoine Ier, MC 98000 (Monaco); Reveillac, E. [Littoral, Environnement et Societes (LIENSs) UMR 6250 CNRS-Universite de La Rochelle, Institut du Littoral et de l' Environnement, 2 rue Olympe de Gouges, F-17042 La Rochelle Cedex 01 (France); Oberhaensli, F.; Teyssie, J.L. [International Atomic Energy Agency - Environment Laboratories, 4 Quai Antoine Ier, MC 98000 (Monaco); Jeffree, R. [International Atomic Energy Agency - Environment Laboratories, 4 Quai Antoine Ier, MC 98000 (Monaco); School of the Environment, Science Faculty, University of Technology Sydney, NSW, 2007 (Australia); Gattuso, J.P. [INSU-CNRS, Laboratoire d' Oceanographie de Villefranche, B.P. 28, 06234 Villefranche-sur-mer Cedex (France); Universite Pierre et Marie Curie, Observatoire Oceanologique de Villefranche, 06230 Villefranche-sur-mer (France)

    2011-09-15

    Highlights: {yields} We study radiotracer uptake in squid embryo and paralarvae under relevant pCO{sub 2}. {yields} We examine metal distribution and concentration factors in egg compartments. {yields} Increasing pCO{sub 2} affects eggshell shielding properties and metal uptake in animals. {yields} Chemical signature in statoliths is modified by higher Zn incorporation under high pCO{sub 2}. {yields} Both element chemical properties and embryo physiology could account for the observed effects. - Abstract: The anthropogenic release of carbon dioxide (CO{sub 2}) into the atmosphere leads to an increase in the CO{sub 2} partial pressure (pCO{sub 2}) in the ocean, which may reach 950 {mu}atm by the end of the 21st century. The resulting hypercapnia (high pCO{sub 2}) and decreasing pH ('ocean acidification') are expected to have appreciable effects on water-breathing organisms, especially on their early-life stages. For organisms like squid that lay their eggs in coastal areas where the embryo and then paralarva are also exposed to metal contamination, there is a need for information on how ocean acidification may influence trace element bioaccumulation during their development. In this study, we investigated the effects of enhanced levels of pCO{sub 2} (380, 850 and 1500 {mu}atm corresponding to pH{sub T} of 8.1, 7.85 and 7.60) on the accumulation of dissolved {sup 110m}Ag, {sup 109}Cd, {sup 57}Co, {sup 203}Hg, {sup 54}Mn and {sup 65}Zn radiotracers in the whole egg strand and in the different compartments of the egg of Loligo vulgaris during the embryonic development and also in hatchlings during their first days of paralarval life. Retention properties of the eggshell for {sup 110m}Ag, {sup 203}Hg and {sup 65}Zn were affected by the pCO{sub 2} treatments. In the embryo, increasing seawater pCO{sub 2} enhanced the uptake of both {sup 110m}Ag and {sup 65}Zn while {sup 203}Hg showed a minimum concentration factor (CF) at the intermediate pCO{sub 2}. {sup 65}Zn

  9. Vestigial phragmocone in the gladius points to a deepwater origin of squid (Mollusca: Cephalopoda)

    Science.gov (United States)

    Arkhipkin, Alexander I.; Bizikov, Vyacheslav A.; Fuchs, Dirk

    2012-03-01

    The microstructure of the gladius cone was investigated in six species of nektonic squid: shallow-water Loligo gahi (Loliginidae), pelagic eurybathic Illex argentinus, Todarodes pacificus, Dosidicus gigas (Ommastrephidae), and deepwater Onykia ingens (Onychoteuthidae) and Gonatus antarcticus (Gonatidae) using state-of-the-art microscopy. Apart from L. gahi, all other species had septa-like layers in the gladius cone, which for the first time were investigated in detail and compared with those in extinct Cretaceous belemnites Hibolithes sp. and Pachyteuthis sp., and spirulid Cyrtobelus sp. It was found that the organic layers of the gladius cone in recent squid can be homologized with the organic components of the shell in fossil phragmocone-bearing coleoids. The septa-like layers in modern gladius cones therefore represent a vestigial phragmocone composed of organic septal rudiments of the ancestral phragmocone that has lost the siphuncle and gas-filled chambers. The well-developed rostrum in onychoteuthids and small rostrum of the gladius in ommastrephids and gonatids can be seen as homologous with the belemnoid rostrum, which may indicate a close phylogenetic relationship between belemnites and at least some squid. Possible evolutionary pathways of the reduction of the functional phragmocone in squid ancestors are discussed. Several features such as the loss of shell calcification, deep water speciation, and the structure of the equilibrium organ point to a deep-water origin of squids.

  10. Assessment of Heavy Metal Contamination in Squid (Loligo Spp.) Tissues of Kedah-Perlis Waters, Malaysia

    International Nuclear Information System (INIS)

    Jamil, T.; Lias, K.; Norsila, D.; Syafinaz, N.S.

    2014-01-01

    This study was carried out to determine the concentration of selected heavy metals (Cd, Cu, Pb and Zn) in three different tissues collected from the ink-sac, head, and muscle of the squid. Squid samples were caught off the coastal waters of Kedah-Perlis, where only mature squids within the maturity size-range of 13 to 15 cm were used. From this study, the concentration of Zn (35.06 ± 4.06 mg/ kg in dry weight) was found significantly higher in all of the tissues, followed by Cu (15.10 ± 13.28 mg/ kg in dry weight), Cd (4.76 ± 3.77 mg/ kg in dry weight), and Pb with an average value of 4.01 ± 0.08 mg/ kg in dry weight. From this study, it was discovered that Zn and Cu concentrations in the tissues were lower than the maximum limit recommended by the Food and Agriculture Organization, Malaysian Food Regulation (1985), as well as other countries. Meanwhile, both non-essential elements namely Cd and Pb recorded higher values than that of the recommended concentrations. According to the Metal Pollution Index (MPI), the ink-sac indicated medium-range contamination, while the head and muscle tissues showed low contamination levels. (author)

  11. The different types of sperm morphology and behavior within a single species: Why do sperm of squid sneaker males form a cluster?

    OpenAIRE

    Hirohashi, Noritaka; Iwata, Yoko

    2013-01-01

    Some coastal squids exhibit male dimorphism (large and small body size) that is linked to mating behaviors. Large “consort” males compete with other, rival males to copulate with a female, and thereby transfer their spermatophores to her internal site around the oviduct. Small “sneaker” males rush to a single female or copulating pair and transfer spermatophores to her external body surface around the seminal receptacle near the mouth. We previously found that in Loligo bleekeri, sneaker sper...

  12. Why small males have big sperm: dimorphic squid sperm linked to alternative mating behaviours.

    Science.gov (United States)

    Iwata, Yoko; Shaw, Paul; Fujiwara, Eiji; Shiba, Kogiku; Kakiuchi, Yasutaka; Hirohashi, Noritaka

    2011-08-10

    Sperm cells are the target of strong sexual selection that may drive changes in sperm structure and function to maximize fertilisation success. Sperm evolution is regarded to be one of the major consequences of sperm competition in polyandrous species, however it can also be driven by adaptation to the environmental conditions at the site of fertilization. Strong stabilizing selection limits intra-specific variation, and therefore polymorphism, among fertile sperm (eusperm). Here we analyzed reproductive morphology differences among males employing characteristic alternative mating behaviours, and so potentially different conditions of sperm competition and fertilization environment, in the squid Loligo bleekeri. Large consort males transfer smaller (average total length = 73 μm) sperm to a female's internal sperm storage location, inside the oviduct; whereas small sneaker males transfer larger (99 μm) sperm to an external location around the seminal receptacle near the mouth. No significant difference in swimming speed was observed between consort and sneaker sperm. Furthermore, sperm precedence in the seminal receptacle was not biased toward longer sperm, suggesting no evidence for large sperm being favoured in competition for space in the sperm storage organ among sneaker males. Here we report the first case, in the squid Loligo bleekeri, where distinctly dimorphic eusperm are produced by different sized males that employ alternative mating behaviours. Our results found no evidence that the distinct sperm dimorphism was driven by between- and within-tactic sperm competition. We propose that presence of alternative fertilization environments with distinct characteristics (i.e. internal or external), whether or not in combination with the effects of sperm competition, can drive the disruptive evolution of sperm size.

  13. Why small males have big sperm: dimorphic squid sperm linked to alternative mating behaviours

    Directory of Open Access Journals (Sweden)

    Shiba Kogiku

    2011-08-01

    Full Text Available Abstract Background Sperm cells are the target of strong sexual selection that may drive changes in sperm structure and function to maximize fertilisation success. Sperm evolution is regarded to be one of the major consequences of sperm competition in polyandrous species, however it can also be driven by adaptation to the environmental conditions at the site of fertilization. Strong stabilizing selection limits intra-specific variation, and therefore polymorphism, among fertile sperm (eusperm. Here we analyzed reproductive morphology differences among males employing characteristic alternative mating behaviours, and so potentially different conditions of sperm competition and fertilization environment, in the squid Loligo bleekeri. Results Large consort males transfer smaller (average total length = 73 μm sperm to a female's internal sperm storage location, inside the oviduct; whereas small sneaker males transfer larger (99 μm sperm to an external location around the seminal receptacle near the mouth. No significant difference in swimming speed was observed between consort and sneaker sperm. Furthermore, sperm precedence in the seminal receptacle was not biased toward longer sperm, suggesting no evidence for large sperm being favoured in competition for space in the sperm storage organ among sneaker males. Conclusions Here we report the first case, in the squid Loligo bleekeri, where distinctly dimorphic eusperm are produced by different sized males that employ alternative mating behaviours. Our results found no evidence that the distinct sperm dimorphism was driven by between- and within-tactic sperm competition. We propose that presence of alternative fertilization environments with distinct characteristics (i.e. internal or external, whether or not in combination with the effects of sperm competition, can drive the disruptive evolution of sperm size.

  14. Effect of Melanin Free Ink Extracted From Squid (Loligo sp.) on Proximate and Sensory Characteristics of Soft-Bone Milkfish (Chanos chanos) During Storage

    Science.gov (United States)

    Winarni Agustini, Tri; Hadiyanto; Wijayanti, Ima; Amalia, Ulfah; Benjakul, Soottawat

    2018-02-01

    Antioxidant could be extracted and isolated from squid inks. Squid ink in the form of melanin free ink (MFI) could be act as an electron donor which can stabilize free radicals in lipid oxidation. This study was carried out to assess the antioxidant activity of squid inks converted into MFI in different dilution and to optimize the extraction conditions for the application of MFI as an antioxidative agent on fish product. Three different types of MFI extracts i.e : pure squid ink, squid ink with 5 times dilution and squid ink with 10 times dilutions by using cooled ionized water (4°C). The ink was then centrifuged at 18.000 x g for 30 minutes at cooled centrifuge (4°C) followed by DPPH analysis. The results showed that the IC50 of MFI extracts were 2.84 ppm; 1.11 ppm and 0.34 ppm, respectively (p squid ink with 10 times dilution in extraction of MFI had the highest value in free radical inhibitory. Although the IC50 of three different dilutions are equally low, and are considered as very strong antioxidative agent, however, it showed that the MFI extracted from squid ink had the ability to prevent free radical

  15. Biosynthesis of fatty acids and cholesterol in squid giant nerve fiber

    International Nuclear Information System (INIS)

    Tanaka, T.; Kishimoto, Y.; Gould, R.M.

    1987-01-01

    The giant nerve fiber of squid 3 (loligo pealel) was incubated with [1- 14 C]acetate and ( 3 H)myristate. Fifty-five percent of the radioactivity incorporated from acetate was recovered in fatty acid methyl esters (FAME). The FAME was fractionated by AgNO 3 -impregnated TLC plate; and 52%, 31%, 0.3%, 5%, and 11% of the radioactivity was recovered in spots associated with saturated, monoenes, dienes, trienes, and polyenes, respectively. The saturated FAME was further fractionated by reverse-phase HPLC; and 4, 47, 1, and 48% of the radioactivity was recovered in 14:0, 16:0, 17:0, and 18:0, respectively. Most radioactivity from polyenes migrated to the spot containing saturated FAME, after catalytical hydrogenation. Cholesterol was isolated and converted to dibromoderivative and the derivative was recrystallized. No radioactivity was found in purified dibromocholesterol. Nearly all radioactivity from myristate-labeled tissue was recovered in saturated FAME. Reverse-phase HPLC showed that 71%, 25%, and 3% of radioactivity was associated with 14:0, 16:0, and 18:0, respectively. These results indicate that the squid giant nerve fibers can synthesize fatty acids by de novo and also by chain elongation and desaturation, though at a slower rate

  16. Use of commercial vessels in survey augmentation: the size-frequency distribution

    Directory of Open Access Journals (Sweden)

    Eric N. Powell

    2006-09-01

    Full Text Available The trend towards use of commercial vessels to enhance survey data requires assessment of the advantages and limitations of various options for their use. One application is to augment information on size-frequency distributions obtained in multispecies trawl surveys where stratum boundaries and sampling density are not optimal for all species. Analysis focused on ten recreationally and commercially important species: bluefish, butterfish, Loligo squid, weakfish, summer flounder, winter flounder, silver hake (whiting, black sea bass, striped bass, and scup (porgy. The commercial vessel took 59 tows in the sampled domain south of Long Island, New York and the survey vessel 18. Black sea bass, Loligo squid, and summer flounder demonstrated an onshore-offshore gradient such that smaller fish were caught disproportionately inshore and larger fish offshore. Butterfish, silver hake, and weakfish were characterized by a southwest-northeast gradient such that larger fish were caught disproportionately northeast of the southwestern-most sector. All sizes of scup, striped bass, and bluefish were caught predominately inshore. Winter flounder were caught predominately offshore. The commercial vessel was characterized by an increased frequency of large catches for most species. Consequently, patchiness was assayed to be higher by the commercial vessel in nearly all cases. The size-frequency distribution obtained by the survey vessel for six of the ten species, bluefish, butterfish, Loligo squid, summer flounder, weakfish, and silver hake, could not be obtained by chance from the size-frequency distribution obtained by the commercial vessel. The difference in sample density did not significantly influence the size-frequency distribution. Of the six species characterized by significant differences in size-frequency distribution between boats, all but one was patchy at the population level and all had one or more size classes so characterized. Although the

  17. Customizing Properties of β-Chitin in Squid Pen (Gladius by Chemical Treatments

    Directory of Open Access Journals (Sweden)

    Alessandro Ianiro

    2014-12-01

    Full Text Available The squid pen (gladius from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the β-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the β-chitin is modified, due to the intercalation of water molecules between β-chitin sheets. Potential applications of these β-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications.

  18. Early life of inshore fishes in Greenland

    DEFF Research Database (Denmark)

    Swalethorp, Rasmus

    to ensure fast growthand avoid starvation. Inshore areas may provide such favorable conditions, as these are sheltered from offshore currents and act as physical barriers that restrict dispersal and drift of eggs and larvae. Even though inshore spawning grounds of e.g. Atlantic cod (Gadus morhua) has been...... a seasonal study on a West Greenlandic inshore population of Atlantic cod. I followed the distribution, development and mortality of eggs and larvae in relation to the physical conditions and the prey availability. The spawning of this population of cod was restricted to a shallow inshore area located...... from the area was limited. Later, the seasonal breakup of ice in a connecting river resulted in an increased freshwater outflow, then enhancing the dispersal of the older larvae. Throughout the study, marked spatial and temporal differences in the zooplankton community composition were observed...

  19. Sperm from sneaker male squids exhibit chemotactic swarming to CO₂.

    Science.gov (United States)

    Hirohashi, Noritaka; Alvarez, Luis; Shiba, Kogiku; Fujiwara, Eiji; Iwata, Yoko; Mohri, Tatsuma; Inaba, Kazuo; Chiba, Kazuyoshi; Ochi, Hiroe; Supuran, Claudiu T; Kotzur, Nico; Kakiuchi, Yasutaka; Kaupp, U Benjamin; Baba, Shoji A

    2013-05-06

    Behavioral traits of sperm are adapted to the reproductive strategy that each species employs. In polyandrous species, spermatozoa often form motile clusters, which might be advantageous for competing with sperm from other males. Despite this presumed advantage for reproductive success, little is known about how sperm form such functional assemblies. Previously, we reported that males of the coastal squid Loligo bleekeri produce two morphologically different euspermatozoa that are linked to distinctly different mating behaviors. Consort and sneaker males use two distinct insemination sites, one inside and one outside the female's body, respectively. Here, we show that sperm release a self-attracting molecule that causes only sneaker sperm to swarm. We identified CO2 as the sperm chemoattractant and membrane-bound flagellar carbonic anhydrase as its sensor. Downstream signaling results from the generation of extracellular H(+), intracellular acidosis, and recovery from acidosis. These signaling events elicit Ca(2+)-dependent turning behavior, resulting in chemotactic swarming. These results illuminate the bifurcating evolution of sperm underlying the distinct fertilization strategies of this species. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Spectral and spatial properties of polarized light reflections from the arms of squid (Loligo pealeii) and cuttlefish (Sepia officinalis L.).

    Science.gov (United States)

    Chiou, Tsyr-Huei; Mäthger, Lydia M; Hanlon, Roger T; Cronin, Thomas W

    2007-10-01

    On every arm of cuttlefish and squid there is a stripe of high-reflectance iridophores that reflects highly polarized light. Since cephalopods possess polarization vision, it has been hypothesized that these polarized stripes could serve an intraspecific communication function. We determined how polarization changes when these boneless arms move. By measuring the spectral and polarizing properties of the reflected light from samples at various angles of tilt and rotation, we found that the actual posture of the arm has little or no effect on partial polarization or the e-vector angle of the reflected light. However, when the illumination angle changed, the partial polarization of the reflected light also changed. The spectral reflections of the signals were also affected by the angle of illumination but not by the orientation of the sample. Electron microscope samples showed that these stripes are composed of several groups of multilayer platelets within the iridophores. The surface normal to each group is oriented at a different angle, which produces essentially constant reflection of polarized light over a range of viewing angles. These results demonstrate that cuttlefish and squid could send out reliable polarization signals to a receiver regardless of arm orientation.

  1. Evidence that glutamate mediates axon-to-Schwann cell signaling in the squid.

    Science.gov (United States)

    Lieberman, E M; Abbott, N J; Hassan, S

    1989-01-01

    High-frequency stimulation (100 Hz) of isolated giant axons of the small squid Alloteuthis subulata and the large squid Loligo forbesi caused the periaxonal Schwann cell resting potential (Em = -40 mV) to hyperpolarize up to 11 mV in direct proportion to train duration and action potential amplitude. In both species, the Schwann cell also hyperpolarized up to 17 mV with the application of L-glutamate (10(-9) to 10(-6) M), in a dose-dependent manner. By contrast, in the presence of 10(-8) M d-tubocurarine (d-TC) to block the cholinergic component of the Schwann cell response, Schwann cells depolarized 8-9 mV during electrical stimulation of the axon or application of L-glutamate. In the presence of 10(-5) M 2-amino-4-phosphonobutyrate (2-APB), the hyperpolarization to glutamate and to axon stimulation was blocked, whereas the cholinergic (carbachol-induced) hyperpolarization was unaffected. In experiments with Alloteuthis, L-aspartate (10(-7) M) also caused a Schwann cell hyperpolarization, but this was not blocked by 2-APB. In tests with glutamate receptor agonists and antagonists, quisqualate (10(-5) M) produced a hyperpolarization blocked by 10(-4) M L-glutamic acid diethylester (GDEE), which also blocked the response to axonal stimulation. Kainic acid (10(-4) M) also caused a hyperpolarization, but n-methyl-D-aspartate (NMDA; 10(-4) M), ibotenate (10(-5) M), alpha-amino-3-hydroxy-5-methyl-isoxazole proprionate (AMPA; (10(-4) M), and isethionate (10(-5) M) had no effect.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Low noise SQUIDS

    International Nuclear Information System (INIS)

    Waal, V.J. de.

    1983-01-01

    The design, fabrication and limitations of very sensitive SQUID magnetometers are described. The SQUID magnetometer is based on the Josephson effect. A very low-noise niobium SQUID is described. It is fabricated with ultra-small niobium junctions with an overlapping area smaller than 1 μm 2 . The photolithographic technique developed for its fabrication, is described. Also an integrated system with a SQUID and a first-order gradiometer on a single substrate is presented. Calculations of the resolution of a dc SQUID containing ideal Josephson junctions according to the RSJ model are presented including a parasitic capacitance. The usefulness of the fabricated SQUIDS as well as some remarks on their performance is considered. (Auth.)

  3. Characterization, localization and function of pertussis toxin-sensitive G proteins in the nervous systems of Aplysia and Loligo

    International Nuclear Information System (INIS)

    Vogel, S.S.

    1989-01-01

    The author has characterized pertussis toxin-sensitive G proteins in the nervous systems of the gastropod mollusc Aplysia and the cephalopod Loligo using [ 32 P]ADP-ribosylation and immunoblotting with G protein specific antisera. As in vertebrates, this class of G protein is associated with membranes and enriched in nervous tissue in Aplysia. Analysis of dissected Aplysia ganglia reveal that it is enriched in neuropil, a region containing most of the central nervous system synapses. Because both Aplysia and Loligo synaptosomes are enriched in pertussis toxin-sensitive G proteins, it is likely that they are found in synaptic terminals. Fractionation of Aplysia synaptosomes into membrane and vesicle fractions reveals that, although the majority of G protein is recovered in the plasma membrane fraction, a small proportion is recovered in the vesicle fraction. He shows that G proteins are on intracellular membranes by ADP-ribosylating extruded axoplasm with pertussis toxin. A plausible explanation for vesicular localization of G protein in axoplasm is that G proteins are transported to terminals on vesicles. He has shown, using ligature experiments with Aplysia connectives and temperature block experiments in the giant axon of Loligo, that G proteins move by anterograde fast axonal transport. Injection of pertussis toxin into the identified Aplysia neuron L10 blocks histamine-induced presynaptic inhibition of transmitter release. This suggests that pertussis toxin sensitive G proteins play a role in modulating transmitter release at synaptic terminals. In the giant synapse of Loligo, he presents preliminary data that demonstrates that the activation of G proteins in the presynaptic terminal results in decreased transmitter release

  4. Low noise SQUIDs

    Science.gov (United States)

    de Waal, V. J.

    1983-02-01

    The present investigation deals with the design, fabrication, and limitations of very sensitive SQUID (Superconducting Quantum Interference Device) magnetometers. The SQUID magnetometer is based on a utilization of the Josephson effect. A description of the theoretical background is provided, and high performance DC SQUIDs with submicron niobium Josephson junctions are discussed, taking into account design considerations, fabrication, junction characterization, the performance of the SQUID and input coil, and the gradiometer performance. The simulation and optimization of a DC SQUID with finite capacitance is considered, giving attention to the implementation of a simulation procedure on a hybrid computer.

  5. Low noise SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    De Waal, V.J.

    1983-01-01

    The present investigation deals with the design, fabrication, and limitations of very sensitive SQUID (Superconducting Quantum Interference Device) magnetometers. The SQUID magnetometer is based on a utilization of the Josephson effect. A description of the theoretical background is provided, and high performance DC SQUIDs with submicron niobium Josephson junctions are discussed, taking into account design considerations, fabrication, junction characterization, the performance of the SQUID and input coil, and the gradiometer performance. The simulation and optimization of a DC SQUID with finite capacitance is considered, giving attention to the implementation of a simulation procedure on a hybrid computer. 129 references.

  6. Department of Commerce Semiannual Regulatory Agenda

    Science.gov (United States)

    2010-04-26

    ... Turtle 92 Critical Habitat Designation for Cook Inlet Beluga Whale Under the Endangered Species 0648-AX50... (including gear impacts on Loligo squid egg EFH); and (4) possible limitations on at- sea processing of...

  7. Quantification of hydrolysis of toxic organophosphates and organophosphonates by diisopropyl fluorophosphatase from Loligo vulgaris by in situ Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Gäb, Jürgen; Melzer, Marco; Kehe, Kai; Richardt, André; Blum, Marc-Michael

    2009-02-15

    The enzyme diisopropyl fluorophosphatase (DFPase) from the squid Loligo vulgaris effectively catalyzes the hydrolysis of diisopropyl fluorophosphate (DFP) and a number of organophosphorus nerve agents, including sarin, soman, cyclosarin, and tabun. Up to now, the determination of kinetic data has been achieved by techniques such as pH-stat titration, ion-selective electrodes, and fluorogenic substrate analogs. We report a new assaying method using in situ Fourier transform infrared (FTIR) spectroscopy with attenuated total reflection (ATR) for the real-time determination of reaction rates. The method employs changes in the P-O-R stretching vibration of DFP and nerve agent substrates when hydrolyzed to their corresponding phosphoric and phosphonic acids. It is shown that the Lambert-Beer law holds and that changes in absorbance can be directly related to changes in concentration. Compared with other methods, the use of in situ FTIR spectroscopy results in a substantially reduced reaction volume that adds extra work safety when handling highly toxic substrates. In addition, the new method allows the noninvasive measurement of buffered solutions with varying ionic strengths complementing existing methods. Because the assay is independent of the used enzyme, it should also be applicable to other phosphotriesterase enzymes such as organophosphorus hydrolase (OPH), organophosphorus acid anhydrolase (OPAA), and paraoxonase (PON).

  8. Complete mitochondrial genome of the Loligo opalescence.

    Science.gov (United States)

    Jiang, Lihua; Liu, Wei; Zhu, Aiyi; Zhang, Jianshe; Wu, Changwen

    2016-09-01

    In this study, we determined the complete mitochondrial genome of the Loligo opalescence. The genome was 17,370 bp in length and contained 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 3 main non-coding regions. The composition and order of genes, were similar to most other invertebrates. The overall base composition of L. opalescence is A 38.62%, C 19.40%, T 32.37% and G 9.61%, with a highly A + T bias of 70.99%. All of the three control regions (CR) contain termination-associated sequences and conserved sequence blocks. This mitogenome sequence data would play an important role in the investigation of phylogenetic relationship, taxonomic resolution and phylogeography of the Loliginidae.

  9. SQUID application research in Japan

    International Nuclear Information System (INIS)

    Itozaki, Hideo

    2003-01-01

    Japanese research activities using SQUIDs are reviewed in this paper. Low-T c SQUIDs are applied to multi-channel systems for magnetoencephalogram (MEG) and magnetocardiogram (MCG). High-T c SQUIDs are applied to MCG, nondestructive evaluation (NDE), SQUID microscopy, biological testing using fine magnetic markers, geological surveying, food inspection, large-scale integration (LSI) defect analysis and SQUID-NQR (nuclear quadrupole resonance). These applications of SQUIDs are being researched and developed actively and some of them are expected to be in the commercial market in the near future

  10. The apparent disappearance of Loligo forbesi from the south of its range in the 1990s: Trends in Loligo spp. abundance in the northeast Atlantic and possible environmental influences

    OpenAIRE

    Chen, C; Pierce, G; Wang, J; Robin, J; Poulard, Jean-charles; Pereira, J; Zuur, A; Boyle, P; Bailey, N; Beare, D; Jereb, P; Ragonese, S; Mannini, A; Orsi-relini, L

    2006-01-01

    Since the early 1990s, Loligoforbesi has apparently disappeared from much of the southern part of its former range, with catches off the Iberian Peninsula, for example, declining dramatically during the 1990s. The present paper assembles data from fishery and research cruise databases to examine the evidence for a shift in distribution, examine the relationship between abundance of this species and that of the partially sympatric Loligo vulgaris, and identify possible environmental correlates...

  11. The SQUID Handbook

    CERN Document Server

    Braginski, Alex I

    2006-01-01

    This two-volume handbook offers a comprehensive and well coordinated presentation of SQUIDs (Superconducting Quantum Interference Devices), including device fundamentals, design, technology, system construction and multiple applications. It is intended to bridge the gap between fundamentals and applications, and will be a valuable textbook reference for graduate students and for professionals engaged in SQUID research and engineering. It will also be of use to specialists in multiple fields of practical SQUID applications, from human brain research and heart diagnostics to airplane and nuclear

  12. DDT residues in fishes from the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Shailaja, M.S.; SenGupta, R.

    degrees E) were obtained from the commercial jetty within 2 h of landing while those from the open sea (16 degrees 30'N 69 degrees E-19 degrees 30'N 67 degrees E) such as Tylosurus sp. (longtom), Coryphaena hippurus (dolphin fish), Loligo sp. (squid...

  13. NanoSQUIDs: Basics & recent advances

    Science.gov (United States)

    José Martínez-Pérez, Maria; Koelle, Dieter

    2017-08-01

    Superconducting Quantum Interference Devices (SQUIDs) are one of the most popular devices in superconducting electronics. They combine the Josephson effect with the quantization of magnetic flux in superconductors. This gives rise to one of the most beautiful manifestations of macroscopic quantum coherence in the solid state. In addition, SQUIDs are extremely sensitive sensors allowing us to transduce magnetic flux into measurable electric signals. As a consequence, any physical observable that can be converted into magnetic flux, e.g., current, magnetization, magnetic field or position, becomes easily accessible to SQUID sensors. In the late 1980s it became clear that downsizing the dimensions of SQUIDs to the nanometric scale would encompass an enormous increase of their sensitivity to localized tiny magnetic signals. Indeed, nanoSQUIDs opened the way to the investigation of, e.g., individual magnetic nanoparticles or surface magnetic states with unprecedented sensitivities. The purpose of this chapter is to present a detailed survey of microscopic and nanoscopic SQUID sensors. We will start by discussing the principle of operation of SQUIDs, placing the emphasis on their application as ultrasensitive detectors for small localized magnetic signals. We will continue by reviewing a number of existing devices based on different kinds of Josephson junctions and materials, focusing on their advantages and drawbacks. The last sections are left for applications of nanoSQUIDs in the fields of scanning SQUID microscopy and magnetic particle characterization, placing special stress on the investigation of individual magnetic nanoparticles.

  14. Vortex electronis and squids

    CERN Document Server

    2003-01-01

    Understanding the nature of vortices in high-Tc superconductors is a crucial subject for research on superconductive electronics, especially for superconducting interference devices (SQUIDs), it is also a fundamental problem in condensed-matter physics. Recent technological progress in methods for both direct and indirect observation of vortices, e.g. scanning SQUID, terahertz imaging, and microwave excitation, has led to new insights into vortex physics, the dynamic behavior of vortices in junctions and related questions of noise. This book presents the current status of research activity and provides new information on the applications of SQUIDs, including magnetocardiography, immunoassays, and laser-SQUID microscopes, all of which are close to being commercially available.

  15. Interpreting behavioural data from Radio-Acoustic Positioning ...

    African Journals Online (AJOL)

    To detect behavioural patterns of individually tagged squid Loligo vulgaris reynaudii in a Radio-Acoustic Positioning Telemetry (RAPT) buoy array, trajectories reflecting the four dimensions of latitude, longitude, depth and time were plotted from data collected during field experiments in South Africa. Finding a continuous ...

  16. SQUID in NDT

    International Nuclear Information System (INIS)

    Rashdi Shah Ahmad

    2001-01-01

    Superconducting Quantum Interference Device (SQUID) is the most sensitive magnetic flux sensor. It has been used to map the magnetic field on the scalp of human being generated by the brain activity. Currently, a number of groups have tried using SQUID for some special NDT application. This paper reviews some of these work. (Author)

  17. El desarrollo temprano del calamar patagónico Loligo gahi D’Orbigny,1835 en aguas peruanas (Cephalopoda: Loliginidae

    Directory of Open Access Journals (Sweden)

    Franz Cardoso

    2013-05-01

    Full Text Available El desarrollo temprano del calamar patagónico, Loligo gahi D’Orbigny, 1835 fue estudiado en el campo y en el laboratorio. Las puestas colectadas en la Isla San Lorenzo, Perú, fueron transferidas al laboratorio, e incubadas en un sistema cerrado de agua marina. Las cápsulas midieron de 88 a 169 mm de longitud y cada cápsula contenía entre 56 y 114 huevos fertilizados. Los huevos midieron de 1,7 a 2,1 mm de longitud y la longitud del manto de los individuos eclosionados varió de 1,9 a 2,8 mm. El desarrollo de las paralarvas se logró a los 20 días, a una temperatura promedio de 19 ºC. El patrón de desarrollo embrionario es similar al observado en otras especies de Loligo. Las paralarvas sobrevivieron 45 días con una dieta de zooplancton (copepódos, micidáceos y larvas de poliquetos.

  18. The different types of sperm morphology and behavior within a single species: Why do sperm of squid sneaker males form a cluster?

    Science.gov (United States)

    Hirohashi, Noritaka; Iwata, Yoko

    2013-11-01

    Some coastal squids exhibit male dimorphism (large and small body size) that is linked to mating behaviors. Large "consort" males compete with other, rival males to copulate with a female, and thereby transfer their spermatophores to her internal site around the oviduct. Small "sneaker" males rush to a single female or copulating pair and transfer spermatophores to her external body surface around the seminal receptacle near the mouth. We previously found that in Loligo bleekeri, sneaker sperm are ~50% longer than consort sperm, and only the sneaker sperm, once ejaculated from the spermatophore (sperm mass), form a cluster because of chemoattraction toward their own respiratory CO2. Here, we report that sperm clusters are able to move en masse. Because a fraction of ejaculated sperm from a sneaker's spermatophore are eventually located in the female's seminal receptacle, we hypothesize that sperm clustering facilitates collective migration to the seminal receptacle or an egg micropyle. Sperm clustering is regarded as a cooperative behavior that may have evolved by sperm competition and/or physical and physiological constraints imposed by male mating tactics.

  19. STM-SQUID probe microscope

    International Nuclear Information System (INIS)

    Hayashi, Tadayuki; Tachiki, Minoru; Itozaki, Hideo

    2007-01-01

    We have developed a STM-SQUID probe microscope. A high T C SQUID probe microscope was combined with a scanning tunneling microscope for investigation of samples at room temperature in air. A high permeability probe needle was used as a magnetic flux guide to improve the spatial resolution. The probe with tip radius of less than 100 nm was prepared by microelectropolishing. The probe was also used as a scanning tunneling microscope tip. Topography of the sample surface could be measured by the scanning tunneling microscope with high spatial resolution prior to observation by SQUID microscopy. The SQUID probe microscope image could be observed while keeping the distance from the sample surface to the probe tip constant. We observed a topographic image and a magnetic image of Ni fine pattern and also a magnetically recorded hard disk. Furthermore we have investigated a sample vibration method of the static magnetic field emanating from a sample with the aim of achieving a higher signal-to-noise (S/N) ratio

  20. The Stationary SQUID

    Science.gov (United States)

    Berger, Jorge

    2018-06-01

    In the customary mode of operation of a SQUID, the electromagnetic field in the SQUID is an oscillatory function of time. In this situation, electromagnetic radiation is emitted and couples to the sample. This is a back action that can alter the state that we intend to measure. A circuit that could perform as a stationary SQUID consists of a loop of superconducting material that encloses the magnetic flux, connected to a superconducting and to a normal electrode. This circuit does not contain Josephson junctions, or any other miniature feature. We study the evolution of the order parameter and of the electrochemical potential in this circuit; they converge to a stationary regime, and the voltage between the electrodes depends on the enclosed flux. We obtain expressions for the power dissipation and for the heat transported by the electric current; the validity of these expressions does not rely on a particular evolution model for the order parameter. We evaluate the influence of fluctuations. For a SQUID perimeter of the order of 1μ m and temperature 0.9T_c, we obtain a flux resolution of the order of 10^{-5}Φ _0/Hz^{1/2}; the resolution is expected to improve as the temperature is lowered.

  1. Paleomagnetic Analysis Using SQUID Microscopy

    Science.gov (United States)

    Weiss, Benjamin P.; Lima, Eduardo A.; Fong, Luis E.; Baudenbacher, Franz J.

    2007-01-01

    Superconducting quantum interference device (SQUID) microscopes are a new generation of instruments that map magnetic fields with unprecedented spatial resolution and moment sensitivity. Unlike standard rock magnetometers, SQUID microscopes map magnetic fields rather than measuring magnetic moments such that the sample magnetization pattern must be retrieved from source model fits to the measured field data. In this paper, we presented the first direct comparison between paleomagnetic analyses on natural samples using joint measurements from SQUID microscopy and moment magnetometry. We demonstrated that in combination with apriori geologic and petrographic data, SQUID microscopy can accurately characterize the magnetization of lunar glass spherules and Hawaiian basalt. The bulk moment magnitude and direction of these samples inferred from inversions of SQUID microscopy data match direct measurements on the same samples using moment magnetometry. In addition, these inversions provide unique constraints on the magnetization distribution within the sample. These measurements are among the most sensitive and highest resolution quantitative paleomagnetic studies of natural remanent magnetization to date. We expect that this technique will be able to extend many other standard paleomagnetic techniques to previously inaccessible microscale samples.

  2. Squid are important components of foodwebs in most marine ...

    African Journals Online (AJOL)

    spamer

    hábitos alimentares e ciclo reprodutivo de Loligo san- paulensis Brakoniecki ... 32(7): 1073–1078. CAPITOLI, R. R. and M. HAIMOVICI 1993 — Alimentacion del .... tribuição, abundância morfologia e reprodução, nas águas litorâneas do Rio ...

  3. Influence of natural inshore and offshore thermal regimes on egg development and time of hatch in American lobsters, Homarus americanus.

    Science.gov (United States)

    Goldstein, Jason S; Watson, Winsor H

    2015-02-01

    Some egg-bearing (ovigerous) American lobsters (Homarus americanus) make seasonal inshore-to-offshore movements, subjecting their eggs to different thermal regimes than those of eggs carried by lobsters that do not make these movements. Our goal was to determine if differences in thermal regimes influence the rate of egg development and the subsequent time of hatch. We subjected ovigerous lobsters to typical inshore or offshore water temperatures from September to August in the laboratory (n=8 inshore and 8 offshore, each year) and in the field (n=8 each, inshore and offshore), over 2 successive years. Although the rate of egg development did not differ significantly between treatments in the fall (P∼0.570), eggs exposed to inshore thermal regimes developed faster in the spring (Plobsters exposed to offshore thermal regimes accumulated more GDD in the winter than did eggs carried by inshore lobsters, while eggs exposed to inshore temperatures acquired them more rapidly in the spring. Results suggest that seasonal movements of ovigerous lobsters influence the time and location of hatching, and thus the transport and recruitment of larvae to coastal and offshore locations. © 2015 Marine Biological Laboratory.

  4. SQUID technology for geophysical exploration

    International Nuclear Information System (INIS)

    Meyer, Hans-Georg; Stolz, R.; Chwala, A.; Schulz, M.

    2005-01-01

    We report on successful tests of planar LTS SQUID gradiometers on airborne platforms such as helicopter and aircraft. The system works stable and allows profile work without any constraints. In mobile applications the gradient resolution at low frequencies is dominated by motion noise, since the parasitic areas of the SQUID gradiometer lead to strong disturbances if the gradiometer is tilted in the homogenous Earth's magnetic field. The balance can be improved further by software using data of a SQUID magnetometer triple. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. SQUIDs for the readout of metallic magnetic calorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Ferring, Anna; Wegner, Mathias; Fleischmann, Andreas; Gastaldo, Loredana; Kempf, Sebastian; Enss, Christian [Kirchhoff-Institute for Physics, Heidelberg University (Germany)

    2015-07-01

    Superconducting quantum interference devices (SQUIDs) are the devices of choice to read out metallic magnetic calorimeters (MMCs). Here, the temperature change of the detector upon the absorption of an energetic particle is measured as a magnetization change of a paramagnetic temperature sensor that is situated in a weak magnetic field. Driven by the need for devices that allow for the readout of large-scale detector arrays with hundreds or even thousands of individual detectors as well as of single channel detectors with sub-eV energy resolution, we have recently started the development of low-T{sub c} current-sensing SQUIDs. In particular, we are developing cryogenic frequency-domain multiplexers based on non-hysteretic rf-SQUIDs for detector array readout as well as dc-SQUIDs for single channel detector readout. We discuss our SQUID designs and the performance of prototype SQUIDs. We particularly focus on the frequency and temperature dependence of the SQUID noise as well as the reliability of our SQUID fabrication process for Nb/Al-AlO{sub x}/Nb Josephson junctions. Additionally, we demonstrate experimentally that state-of-the-art MMCs can successfully be read out with our current devices. Finally, we discuss different strategies to improve the SQUID and detector performance aiming to reach sub-eV energy resolution for individual detectors as well as for detector arrays.

  6. Design of a hysteretic SQUID as the readout for a dc SQUID

    International Nuclear Information System (INIS)

    Gershenson, M.

    1991-01-01

    This paper present a design for an optimal hysteretic SQUID readout circuit for a DC SQUID, thus eliminating the need for bulky output transformers or resonance matching circuits. The hysteretic readout system, which is based in part on standard sampling theory, is compared to another similar system and shown to be superior in terms of slew rate and immunity of electromagnetic interference. The circuit will be useful in optimizing the performance of biomagnetic systems

  7. Review of SQUID Sensors for Measuring Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Kim, J. M.; Yu, K. K.; Kim, K.; Kwon, H. [Brain and Cognition Measurement Lab, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2011-08-15

    Measurement of magnetic signals generated from electric activity of myocardium provides useful information for the functional diagnosis of heart diseases. Key technical component of the magnetocardiography (MCG) technology is SQUID. To measure MCG signals with high signal-to-noise ratio, sensitive SQUID magnetic field sensors are needed. Present magnetic field sensors based on Nb SQUIDs have field sensitivity good enough to measure most of MCG signals. However, for accurate measurement of fine signal pattern or detection of local atrial fibrillation signals, we may need higher field sensitivity. In addition to field sensitivity, economic aspect of the SQUID system is also important. To simplify the SQUID readout electronics, the output voltage or flux-to-voltage transfer of SQUID should be large enough so that direct measurement of SQUID output can be done using room-temperature preamplifiers. Double relaxation oscillation SQUID (DROS), having about 10 times larger flux-to-voltage transfers than those of DC-SQUIDs, was shown to be a good choice to make the electronics compact. For effective cancellation of external noise inside a thin economic shielded room, first-order axial gradiometer with high balance, simple structure and long-baseline is needed. We developed a technology to make the axial gradiometer compact using direct bonding of superconductive wires between pickup coil and input coil. Conventional insert has mechanical support to hold the gradiometer array, and the dewar neck has equal diameter with the dewar bottom. Boiling of the liquid He can generate mechanical vibrations in the gradiometer array due to mechanical connection structure. Elimination of the mechanical support, and direct mounting of the gradiometer array into the dewar bottom can reduce the dewar neck diameter, resulting in the reduction of liquid He consumption.

  8. Squids: principles and basic applications in experimental physics

    International Nuclear Information System (INIS)

    Ocio, M.

    1990-01-01

    The basic principles and the description of the technical aspects of SQUIDs (Superconducting Quantum Interference Devices) are described. The applications of SQUIDs in experimental researches and low temperature physics experiments are given. The concepts of fluxoid quantization in a superconductor and Josephson tunnelling are reviewed. The principles, the operation, the noise and the different configurations of r.f. and direct current bias SQUIDs are summarized. The principal characteristics of several SQUIDs are reported

  9. Bionomics of brown crab Cancer pagurus in the south east Ireland inshore fishery

    OpenAIRE

    Fahy, E.; Hickey, J.; Perella, N.; Hervas, A.; Carroll, J.; Andray, C.

    2004-01-01

    The south east inshore brown crab fishery is delimited by the boundary of longitude - 6.3, within a coastal band of approximately 18 km (10 nm) in width and it extends along the south coast of Co Wexford for a distance of approximately 55 km; evidence for the stock extending into the inshore fishery west of the Waterford Harbour estuary is sparse. The fishery, whose maximum extent is calculated at 427 km2, yielded up to 700 t per year during the 1990s. In 2002 annual landings of 959 t account...

  10. Properties of the Agulhas Current's Inshore Front During The Shelf Agulhas Glider Experiment (SAGE)

    Science.gov (United States)

    Krug, M.; Swart, S.; Goschen, W.

    2016-02-01

    The response of coastal and shelf regions to changes in the Agulhas Current remains poorly studied. This is partly due to observational challenges associated with sampling western boundary currents. Cross-shelf exchange in such energetic current systems occurs through a range of meso- ( 50-200 km) and sub-meso (sample the energetic inshore regions of the Agulhas Current at a high spatial (100's of meters to 3km - well within the sub-mesoscale range) and temporal (0.5-4 hourly) resolution. In April 2015, two SeaGliders were deployed off Port Elizabeth (34S) at the inshore edge of the Agulhas Current as part of the Shelf Agulhas Glider Experiment (SAGE), testing for the very 1st time the feasibility of operating autonomous platforms in this highly turbulent and energetic western boundary current system. For a period of approximately two months, the Seagliders provided continuous observations at the inshore boundary of the Agulhas Current at an unprecedented spatial resolution. Observations from the Seagliders showed that at the inshore edge of the Agulhas Current, both surface and depth averaged currents are aligned in a south-west / north- east direction, with stronger flows encountered over deeper regions of the shelf, when the gliders are closer to the Agulhas Current. In the absence of large meanders, the mean flow at the inshore boundary of the Agulhas Current is characterised by strong shear with a counter current flowing in opposite direction to the mean current field. Instances of counter currents occur 45% of the time in the surface flow and 54% of the time in the depth-averaged record. More than 80% of return flow occurrences occur when glider is in water depth of less than 200m.

  11. Computer model for noise in the dc Squid

    International Nuclear Information System (INIS)

    Tesche, C.D.; Clarke, J.

    1976-08-01

    A computer model for the dc SQUID is described which predicts signal and noise as a function of various SQUID parameters. Differential equations for the voltage across the SQUID including the Johnson noise in the shunted junctions are integrated stepwise in time

  12. YBCO SQUIDs with unconventional current phase relation

    International Nuclear Information System (INIS)

    Bauch, T.; Johansson, J.; Cedergren, K.; Lindstroem, T.; Lombardi, F.

    2007-01-01

    We have studied the dynamics of YBa 2 Cu 3 O 7-δ (YBCO) dc sperconducting quantum interference devices (SQUIDs) characterized by an unconventional Josephson current phase relation (CPR). We have focused on SQUID configurations with Josephson junctions where the lobe of the order parameter in one electrode is facing a node in the other electrode. This order parameter arrangement should enhance the appearance of a sin(2φ) term in the CPR. The response of the critical current of the dc SQUID, under the effect of an external magnetic field, has been measured in temperature, down to 20 mK. Our experimental data have been compared with numerical simulations of the SQUIDs dynamics by considering a CPR of a single junction of the form I(φ) = I I sin(φ) - I II sin(2φ) where I I and I II are, respectively, the first and second harmonic component. In our devices the values of the sin(2φ) term are such that the fundamental state of the SQUID is naturally double degenerate. This is of great relevance for applications of d-wave SQUIDs in quantum information processing

  13. Antioxidant and antimicrobial activities of squid ink powder

    OpenAIRE

    Fatimah Zaharah, M.Y.; Rabeta, M.S.

    2017-01-01

    Economic development in Malaysia has led to increasing quantity and complexity of generated waste or by-product. The main objective of this study is to investigate the antioxidant and antimicrobial activities of squid ink powder. The squid ink was collected from fresh squid and dried using freeze dryer before it was ground into powder. The yield of squid ink was 22.82% after freeze-drying which was 69.37g in amount. Proximate composition analysis as well as two total antioxidant activity assa...

  14. High speed non-latching squid binary ripple counter

    International Nuclear Information System (INIS)

    Silver, A.H.; Phillips, R.R.; Sandell, R.D.

    1985-01-01

    High speed, single flux quantum (SFQ) binary scalers are important components in superconducting analog-to-digital converters (ADC). This paper reviews the concept for a SQUID ADC and the design of an SFQ binary ripple counter, and reports the simulation of key components, and fabrication and performance of non-latching SQUID scalers and SFQ binary ripple counters. The SQUIDs were fabricated with Nb/Nb 2 O 5 /PbIn junctions and interconnected by monolithic superconducting transmission lines and isolation resistors. Each SQUID functioned as a bistable flip-flop with the input connected to the center of the device and the output across one junction. All junctions were critically damped to optimize the pulse response. Operation was verified by observing the dc I-V curves of successive SQUIDs driven by a cw pulse train generated on the same chip. Each SQUID exhibited constant-voltage current steps at 1/2 the voltage of the preceding device as expected from the Josephson voltage-to-frequency relation. Steps were observed only for the same voltage polarity of successive devices and for proper phase bias of the SQUID. Binary frequency division was recorded up to 40GHz for devices designed to operate to 28GHz

  15. Antioxidant and antimicrobial activities of squid ink powder

    Directory of Open Access Journals (Sweden)

    Fatimah Zaharah, M.Y.

    2017-10-01

    Full Text Available Economic development in Malaysia has led to increasing quantity and complexity of generated waste or by-product. The main objective of this study is to investigate the antioxidant and antimicrobial activities of squid ink powder. The squid ink was collected from fresh squid and dried using freeze dryer before it was ground into powder. The yield of squid ink was 22.82% after freeze-drying which was 69.37g in amount. Proximate composition analysis as well as two total antioxidant activity assays named 2,2-diphenyl-1-picrylhydrazyl (DPPH assay and Ferric Reducing Antioxidant Power (FRAP assay, and antimicrobial analysis were done on the powdered squid ink. The proximate results of squid ink powder were 4.43 ± 0.29% moisture, 62.46 ± 0.62% protein, 3.96 ± 0.08% fat, and 9.29 ± 0.05% ash. Results of DPPH assay showed that water extraction of squid ink powder has the highest 94.87 ± 4.87%, followed by ethanol 67.57 ± 7.55%, and hexane extract 2.10 ± 1.18%. FRAP assay result presented the same trend with water extraction had the highest value of 929.67 ± 2.31 μmol Fe (II / g of sample extract, followed by ethanol extract 201.00 ± 26.29 μmol Fe (II per gram sample and hexane 79.67 ± 12.66 μmol Fe (II / g of sample extract. Both water and ethanol extract showed antimicrobial properties with inhibition range of 7 to 15 mm, respectively. Fresh squid ink had 1.254 × 103 colony forming unit per gram of sample of microbial content. Squid ink powder had protein as major compound and microbial content was below from standard value of fisheries products as stated in Food Act 1983 and Regulation 1985.

  16. Cold SQUIDs and hot samples

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T.S.C. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley national Lab., CA (United States). Materials Sciences Div.

    1997-05-01

    Low transition temperature (low-{Tc}) and high-{Tc} Superconducting QUantum Interference Devices (SQUIDs) have been used to perform high-resolution magnetic measurements on samples whose temperatures are much higher than the operating temperatures of the devices. Part 1 of this work focuses on measurements of the rigidity of flux vortices in high-{Tc} superconductors using two low-{Tc} SQUIDs, one on either side of a thermally-insulated sample. The correlation between the signals of the SQUIDs is a direct measure of the extent of correlation between the movements of opposite ends of vortices. These measurements were conducted under the previously-unexplored experimental conditions of nominally-zero applied magnetic field, such that vortex-vortex interactions were unimportant, and with zero external current. At specific temperatures, the authors observed highly-correlated noise sources, suggesting that the vortices moved as rigid rods. At other temperatures, the noise was mostly uncorrelated, suggesting that the relevant vortices were pinned at more than one point along their length. Part 2 describes the design, construction, performance, and applications of a scanning high-{Tc} SQUID microscope optimized for imaging room-temperature objects with very high spatial resolution and magnetic source sensitivity.

  17. Cold SQUIDs and hot samples

    International Nuclear Information System (INIS)

    Lee, T.S.C.; Lawrence Berkeley national Lab., CA

    1997-05-01

    Low transition temperature (low-T c ) and high-T c Superconducting QUantum Interference Devices (SQUIDs) have been used to perform high-resolution magnetic measurements on samples whose temperatures are much higher than the operating temperatures of the devices. Part 1 of this work focuses on measurements of the rigidity of flux vortices in high-T c superconductors using two low-T c SQUIDs, one on either side of a thermally-insulated sample. The correlation between the signals of the SQUIDs is a direct measure of the extent of correlation between the movements of opposite ends of vortices. These measurements were conducted under the previously-unexplored experimental conditions of nominally-zero applied magnetic field, such that vortex-vortex interactions were unimportant, and with zero external current. At specific temperatures, the authors observed highly-correlated noise sources, suggesting that the vortices moved as rigid rods. At other temperatures, the noise was mostly uncorrelated, suggesting that the relevant vortices were pinned at more than one point along their length. Part 2 describes the design, construction, performance, and applications of a scanning high-T c SQUID microscope optimized for imaging room-temperature objects with very high spatial resolution and magnetic source sensitivity

  18. Dc-SQUID sensor system for multichannel neuromagnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Houwman, E.P.; Veldhuis, D.; Flokstra, ter Brake, H.J.M.; Jaszczuk, W.; Rogalla, H. (Univ. of Twente, Faculty of Applied Physics, P.O. Box 217, 7500 AE Enschede (NL)); Martinez, A. (Universidad de Zaragoza, E.T.S.I.I. Maria Zambrano 50, 50015 Zaragoza (ES))

    1991-03-01

    This paper reports on various DC-SQUID sensor configurations developed for use in the authors' 19-channel neuromagetometer. Apart from the standard type, resistively and indictively shunted SQUIDs were made, allowing for a large screening factor {beta} ({gt}1). In this way signal coupling from the pick-up coil to the SQUID is facilitated and capactive coupling between the input coil and the SQUID washer can be decreased. The number of turns of the input coil is decreased further by allowing for an inductance mismatch in the input circuit. Although theoretically both measures give rise to an increased field noise of the sensor, they may lead to a reduction of the excess noise and the noise balance may become positive.

  19. Inductance-dependent characteristics of HTS dc-SQUID amplifiers

    International Nuclear Information System (INIS)

    Mitchell, E.E.; Tilbrook, D.L.; Foley, C.P.; MacFarlane, J.

    2002-01-01

    Full text: We have experimentally determined the transfer function V Φ and noise S Φ of several high temperature superconducting (HTS) dc SQUIDs of increasing loop size, while they were operated (without input flux transformer) in a small-signal-amplifier (open-loop) mode. A primary aim of our investigation was to provide reliable inductance data to aid our design of subsequent magnetometer devices. Flux was induced by means of current injection via a well-defined stripline directly into the SQUID loop. The loop size was systematically incremented in a range of otherwise similar SQUIDs. For each SQUID, the ratio between the induced flux and the injection current (which we define as the coupling inductance of the device, L c ) was measured as a function of the injection path length and the SQUID loop dimensions. Both L c and the derived SQUID self-inductance, L sq , were then compared with theoretical values, and contributions due to kinetic inductance and junction inductance were estimated. Correlations between the inductance data and our measured values of transfer function V Φ and noise S Φ were compared with previous results. Guidelines for optimisation of gradiometer SQUIDs were established, and in particular, the importance of achieving a large value transfer function together with a relatively small inductance was demonstrated. The strong influence of an enhanced transfer function was further emphasised when an order-of-magnitude reduction in noise was achieved by subjecting one of our SQUIDs to an in-house 'ion-beam trimming' process

  20. High transition-temperature SQUID magnetometers and practical applications

    International Nuclear Information System (INIS)

    Dantsker, E.; Lawrence Berkeley National Lab., CA

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa 2 Cu 3 O 7-x (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO 3 -YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz -1/2 at 1 Hz and 8.5 fT Hz -1/2 at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz -1/2 at 1 Hz and 18 fT Hz -1/2 at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room

  1. Current-phase relations and noise in rf biased SQUIDS

    International Nuclear Information System (INIS)

    Jackel, L.D.; Clark, T.D.; Buhrman, R.A.

    1975-01-01

    An investigation was made of the effect of the weak link current-phase relation on noise in rf biased SQUIDs. Non-sinusoidal current-phase relations were observed in various weak links, and these non-sinusoidal relations were correlated with significantly increased intrinsic noise in the SQUID ring. The current-phase relation was also found to affect the amplitude of the rf SQUID ring dissipation. The result of an rf SQUID system noise analysis shows that, due to increased intrinsic noise and reduced ring dissipation, the minimum attainable noise for a SQUID ring having a very non-sinusoidal current-phase relation is considerably greater than for a ring with a sinusoidal relation

  2. Feeding ecology of three inshore fish species at Marion Island ...

    African Journals Online (AJOL)

    Three species of fish occur in the shallow inshore waters of Marion Island. Notothenia ... and then expressed as a percentage of the sum of all R.1. values for each ... also spends much of its time lying motionless on the bot- tom. Up to three H.

  3. High transition-temperature SQUID magnetometers and practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Dantsker, Eugene [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa2Cu3O7-x (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO3-YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz-1/2 at 1 Hz and 8.5 fT Hz-1/2 at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz-1/2 at 1 Hz and 18 fT Hz-1/2 at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room.

  4. Radiation detection from phase-locked serial dc SQUID arrays

    DEFF Research Database (Denmark)

    Kaplunenko, V. K.; Mygind, Jesper; Pedersen, Niels Falsig

    1993-01-01

    We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac[approximately-e......We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac...

  5. Nb nanoSQUIDs for detection of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Woelbing, R.; Nagel, J.; Kemmler, M.; Kleiner, R.; Koelle, D. [Physikalisches Institut, Universitaet Tuebingen (Germany); Kieler, O.; Weimann, T.; Kohlmann, J.; Zorin, A. [Fachbereich 2.4 ' ' Quantenelektronik' ' , PTB Braunschweig (Germany); Buchter, A.; Xue, F.; Poggio, M. [Department of Physics, University of Basel (Switzerland); Rueffer, D.; Russo-Averchi, E.; Fontcuberta i Morral, A. [Laboratoire des Materiaux Semiconducteurs, EPF Lausanne (Switzerland); Huber, R.; Berberich, P. [Physik-Department E10, Technische Universitaet Muenchen (Germany); Grundler, D. [Laboratoire des Materiaux Semiconducteurs, EPF Lausanne (Switzerland); Physik-Department E10, Technische Universitaet Muenchen (Germany)

    2013-07-01

    We report on the realization of highly sensitive dc nanoSQUIDs for the investigation of small spin systems in moderate magnetic fields. The Nb SQUIDs are based on normal metal Josephson junctions made of HfTi and patterned by e-beam lithography. We demonstrate stable operation up to B = ± 50 mT without degradation of rms flux noise (S{sub Φ}{sup 1/2} ≤ 280 nΦ{sub 0}/√(Hz)). We also present a multifunctional system combining a Nb nanoSQUID and a low-temperature magnetic force microscope (LTMFM) with a Ni nanotube as a scanning tip. This system allows for magnetization measurements of the Ni tube by using both, LTMFM and SQUID readout. Furthermore, the measurement of magnetic flux Φ vs. position of the particle provides an experimental determination of the coupling factor φ{sub μ} = Φ/μ between SQUID and Ni tube with magnetic moment μ. The results confirm our predictions from numerical simulations, taking into account the SQUID geometry.

  6. Resilient or vulnerable? : a study of the livelihoods of inshore fishers and aquaculturists in Penang, Malaysia

    OpenAIRE

    Lim, Jiunmin

    2016-01-01

    The marine and coastal ecosystem of Penang experiences problems with water pollution and overexploitation of fish stock is not a new phenomenon. The degradation of the marine and coastal ecosystem, coupled with natural hazards such as the 2004 tsunami, have affected the livelihoods of the inshore fishers and aquaculturists who depend on marine and coastal resources for a living. This study addresses the vulnerability and the coping strategies of the inshore fishers and aquaculturists (shrimp,...

  7. Allometry indicates giant eyes of giant squid are not exceptional.

    Science.gov (United States)

    Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Gamarra, Ashlee R; Lee, Johanna J; Wainwright, Peter C

    2013-02-18

    The eyes of giant and colossal squid are among the largest eyes in the history of life. It was recently proposed that sperm whale predation is the main driver of eye size evolution in giant squid, on the basis of an optical model that suggested optimal performance in detecting large luminous visual targets such as whales in the deep sea. However, it is poorly understood how the eye size of giant and colossal squid compares to that of other aquatic organisms when scaling effects are considered. We performed a large-scale comparative study that included 87 squid species and 237 species of acanthomorph fish. While squid have larger eyes than most acanthomorphs, a comparison of relative eye size among squid suggests that giant and colossal squid do not have unusually large eyes. After revising constants used in a previous model we found that large eyes perform equally well in detecting point targets and large luminous targets in the deep sea. The eyes of giant and colossal squid do not appear exceptionally large when allometric effects are considered. It is probable that the giant eyes of giant squid result from a phylogenetically conserved developmental pattern manifested in very large animals. Whatever the cause of large eyes, they appear to have several advantages for vision in the reduced light of the deep mesopelagic zone.

  8. Two-stage SQUID systems and transducers development for MiniGRAIL

    International Nuclear Information System (INIS)

    Gottardi, L; Podt, M; Bassan, M; Flokstra, J; Karbalai-Sadegh, A; Minenkov, Y; Reinke, W; Shumack, A; Srinivas, S; Waard, A de; Frossati, G

    2004-01-01

    We present measurements on a two-stage SQUID system based on a dc-SQUID as a sensor and a DROS as an amplifier. We measured the intrinsic noise of the dc-SQUID at 4.2 K. A new dc-SQUID has been fabricated. It was specially designed to be used with MiniGRAIL transducers. Cooling fins have been added in order to improve the cooling of the SQUID and the design is optimized to achieve the quantum limit of the sensor SQUID at temperatures above 100 mK. In this paper we also report the effect of the deposition of a Nb film on the quality factor of a small mass Al5056 resonator. Finally, the results of Q-factor measurements on a capacitive transducer for the current MiniGRAIL run are presented

  9. The investigation of rf-squids at liquid nitrogen temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Polushkin, V N; Vasiliev, B V [Joint Inst. for Nuclear Research, Dubna (USSR)

    1989-12-01

    One- and two-hole YBCO ceramic rf-squids operating at liquid nitrogen temperatures have been developed. The main squid parameters: self-inductance, white noise level and magnetic flux resolution were measured. The directly measured external field sensitivity for one-hole squid was at the level of 100 fT/{radical}Hz. (orig.).

  10. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    International Nuclear Information System (INIS)

    Heaney, M.B.

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al 2 O 3 /Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 x 10 17 in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO 3 crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies

  11. Temperature-dependent performance of all-NbN DC-SQUID magnetometers

    Science.gov (United States)

    Liu, Quansheng; Wang, Huiwu; Zhang, Qiyu; Wang, Hai; Peng, Wei; Wang, Zhen

    2017-05-01

    Integrated NbN direct current superconducting quantum interference device (DC-SQUID) magnetometers were developed based on high-quality epitaxial NbN/AlN/NbN Josephson junctions for SQUID applications operating at high temperatures. We report the current-voltage and voltage-flux characteristics and the noise performance of the NbN DC-SQUIDs for temperatures ranging from 4.2 to 9 K. The critical current and voltage swing of the DC-SQUIDs decreased by 15% and 25%, respectively, as the temperature was increased from 4.2 to 9 K. The white flux noise of the DC-SQUID magnetometer at 1 kHz increased from 3.9 μΦ0/Hz1/2 at 4.2 K to 4.8 μΦ0/Hz1/2 at 9 K with 23% increase, corresponding to the magnetic field noise of 6.6 and 8.1 fT/Hz1/2, respectively. The results show that NbN DC-SQUIDs improve the tolerance of the operating temperatures and temperature fluctuations in SQUID applications.

  12. Inshore small-mesh trawling survey of the Cape south coast. Part 1 ...

    African Journals Online (AJOL)

    rence of marine nursery grounds of inshore fishes, with particular ... survey of juvenile fIsh inhabiting rocky substrates within the ...... In: Estuarine Ecology with particular reference to southern ... Structural and functional aspects of the surf-.

  13. Iodate in inshore and offshore waters of Central Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.

    Biological stripping of iodate in the surface waters is noticed in the inshore and offshore waters of Bay of Bengal. A good correlation is observed between iodate and phosphate and nitrate and the molar ratios determined being NO3: PO4: IO3 = 88...

  14. β-Chitin and chitosan from squid gladius: Biological activities of chitosan and its application as clarifying agent for apple juice.

    Science.gov (United States)

    Abdelmalek, Baha Eddine; Sila, Assaâd; Haddar, Anissa; Bougatef, Ali; Ayadi, Mohamed Ali

    2017-11-01

    Chitin is the second most abundant polysaccharide in biomass after cellulose and the term chitosan usually refers to a family of polymers obtained after chitin deacetylation. The aim of this work was the preparation and the characterization of chitin and chitosan from the gladius (pen) of the European squid (Loligo vulgaris). A high level of deproteinization (more than 80%) was recorded using Alcalase ® with an enzyme/protein ratio of 10U/mg. The demineralization of the gladius was completely achieved within 8h at room temperature in HCl. 13 C NMR, FTIR, and XRD diffractograms of prepared chitin and chitosan were taken and then degree of deacetylation of chitosan was calculated using 13 C CP/MAS-NMR Spectroscopic. Further, in vitro antioxidant capacity of chitosan was evaluated on 1,1-diphenyl-2-picrylhydrazyl method (IC 50 =3.2mgmL -1 ) and the β-carotene bleaching assay (IC 50 =3.3mgmL -1 ). Antimicrobial activity was also investigated and assays indicated that prepared chitosan exhibited marked inhibitory activity against all microbial strains tested. Additionally, chitosan was tested such as clarifying agent for apple juice and showed powerful clarification capability, without affecting nutritional value. Furthermore, the results suggested that prepared chitosan could be used as alternative additive in pharmaceutical preparations and food industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Tracking Electromagnetic Energy With SQUIDs

    Science.gov (United States)

    2005-01-01

    A superconducting quantum interference device (SQUID) is a gadget used to measure extremely weak signals, specifically magnetic flux. It can detect subtle changes in energy, up to 100 billion times weaker than the electromagnetic energy required to move a compass needle. SQUIDs are used for a variety of testing procedures where extreme sensitivity is required and where the test instrument need not come into direct contact with the test subject. NASA uses SQUIDs for remote, noncontact sensing in a variety of venues, including monitoring the Earth s magnetic field and tracking brain activity of pilots. Scientists at NASA s Goddard Space Flight Center have been making extensive use of this technology, from astrophysical research, to tracking the navigational paths of bees in flight to determine if they are using internal compasses. These very sensitive measurement devices have a wide variety of uses within NASA and even more uses within the commercial realm.

  16. SQUID use for Geophysics: finding billions of dollars

    Science.gov (United States)

    Foley, Catherine

    2014-03-01

    Soon after their discovery, Jim Zimmerman saw the potential of using Superconducting Quantum Interference Devices, SQUIDs, for the study of Geophysics and undertook experiments to understand the magnetic phenomena of the Earth. However his early experiments were not successful. Nevertheless up to the early 1980's, some research effort in the use of SQUIDs for geophysics continued and many ideas of how you could use SQUIDs evolved. Their use was not adopted by the mining industry at that time for a range of reasons. The discovery of high temperature superconductors started a reinvigoration in the interest to use SQUIDs for mineral exploration. Several groups around the world worked with mining companies to develop both liquid helium and nitrogen cooled systems. The realisation of the achievable sensitivity that contributed to successful mineral discoveries and delineation led to real financial returns for miners. By the mid 2000's, SQUID systems for geophysics were finally being offered for sale by several start-up companies. This talk will tell the story of SQUID use in geophysics. It will start with the early work of the SQUID pioneers including that of Jim Zimmerman and John Clarke and will also cover the development since the early 1990's up to today of a number of magnetometers and gradiometers that have been successfully commercialised and used to create significant impact in the global resources industry. The talk will also cover some of the critical technical challenges that had to be overcome to succeed. It will focus mostly on magnetically unshielded systems used in the field although some laboratory-based systems will be discussed.

  17. A new integrated microwave SQUID circuit design

    International Nuclear Information System (INIS)

    Erne, S.N.; Finnegan, T.F.

    1980-01-01

    In this paper we consider the design and operation of a planar thin-film rf-SQUID circuit which can be realized via microwave-integrated-circuit (MIC) techniques and which differs substantially from pervious microwave SQUID configurations involving either mechanical point-contact or cylindrical thin-film micro-bridge geometries. (orig.)

  18. High Tc Josephson Junctions, SQUIDs and magnetometers

    International Nuclear Information System (INIS)

    Clarke, J.

    1991-01-01

    There has recently been considerable progress in the state-of-the-art of high-T c magnetometers based on dc SQUIDs (Superconducting Quantum Interference Devices). This progress is due partly to the development of more manufacturable Josephson junctions, making SQUIDs easier to fabricate, and partly to the development of multiturn flux transformers that convert the high sensitivity of SQUIDs to magnetic flux to a correspondingly high sensitivity to magnetic field. Needless to say, today's high-T c SQUIDs are still considerably less sensitive than their low-T c counterparts, particularly at low frequencies (f) where their level of 1/f noise remains high. Nonetheless, the performance of the high-T c devices has now reached the point where they are adequate for a number of the less demanding applications; furthermore, as we shall see, at least modest improvements in performance are expected in the near future. In this article, the author outlines these various developments. This is far from a comprehensive review of the field, however, and, apart from Sec. 2, he describes largely his own work. He begins in Sec. 2 with an overview of the various types of Josephson junctions that have been investigated, and in Sec. 3, he describes some of the SQUIDs that have been tested, and assess their performance. Section 4 discuss the development of the multilayer structures essential for an interconnect technology, and, in particular, for crossovers and vias. Section 5 shows how this technology enables one to fabricate multiturn flux transformers which, in turn, can be coupled to SQUIDs to make magnetometers. The performance and possible future improvements in these magnetometers are assessed, and some applications mentioned

  19. Low noise niobium dc SQUID with a planar input coil

    Science.gov (United States)

    de Waal, V. J.; van den Hamer, P.; Klapwijk, T. M.

    1983-02-01

    A practical all-niobium dc superconducting quantum interference device (SQUID) with a niobium spiral input coil has been developed. The SQUID utilizes submicron Josephson junctions. The best intrinsic energy resolution obtained with a 1-nH SQUID is 4×10-32 J/Hz. A 20-turn 1.2-μH input coil is coupled to a 2.3-nH SQUID with an efficiency of 0.5. The energy resolution with respect to the coil is 1×10-30 J/Hz.

  20. Development of an image processing system in splendid squid quality classification

    Science.gov (United States)

    Masunee, Niyada; Chaiprapat, Supapan; Waiyagan, Kriangkrai

    2013-07-01

    Agricultural products typically exhibit high variance in quality characteristics. To assure customer satisfaction and control manufacturing productivity, quality classification is necessary to screen off defective items and to grade the products. This article presents an application of image processing techniques on squid grading and defect discrimination. A preliminary study indicated that surface color was an efficient determinant to justify quality of splendid squids. In this study, a computer vision system (CVS) was developed to examine the characteristics of splendid squids. Using image processing techniques, squids could be classified into three different quality grades as in accordance with an industry standard. The developed system first sifted through squid images to reject ones with black marks. Qualified squids were graded on a proportion of white, pink, and red regions appearing on their bodies by using fuzzy logic. The system was evaluated on 100 images of squids at different quality levels. It was found that accuracy obtained by the proposed technique was 95% compared with sensory evaluation of an expert.

  1. Parameter tolerance of the SQUID bootstrap circuit

    International Nuclear Information System (INIS)

    Zhang Guofeng; Dong Hui; Xie Xiaoming; Jiang Mianheng; Zhang Yi; Krause, Hans-Joachim; Braginski, Alex I; Offenhäusser, Andreas

    2012-01-01

    We recently demonstrated and analysed the voltage-biased SQUID bootstrap circuit (SBC) conceived to suppress the preamplifier noise contribution in the absence of flux modulation readout. Our scheme contains both the additional voltage and current feedbacks. In this study, we analysed the tolerance of the SBC noise suppression performance to spreads in SQUID and SBC circuit parameters. Analytical results were confirmed by experiments. A one-time adjustable current feedback can be used to extend the tolerance to spreads such as those caused by the integrated circuit fabrication process. This should help to improve the fabrication yield of SBC devices integrated on one chip—as required for multi-channel SQUID systems.

  2. Characterisation of micro and nano SQUIDs at variable temperature and magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Koehn, Claudia; Storm, Jan-Hendrik; Bechstein, Sylke; Schurig, Thomas [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany)

    2015-07-01

    SQUIDs are highly suited to investigate the magnetic properties of samples with small dimensions, such as nanoparticles, or to read out nanoelectromechanical systems (NEMS). Due to the small sample size, SQUIDs with dimensions in the μm or nm regime are desirable. These micro or nano SQUIDs should have a low noise and no hysteresis in the current-voltage-characteristic, even when operated in high magnetic fields of up to several 100 mT. To investigate such SQUID, we developed measurement setups which can simulate the measurement conditions of the intended SQUID application. The design and performance of two measurement setups will be shown and compared. One setup uses a dipstick that is immersed in liquid helium and can be evacuated to provide SQUID temperatures between 4.5 K and 10 K. The other one uses an evaporation cryostat so that the temperature can be varied from 2 K to 60 K. Both setups are equipped with coils to enable SQUID operation in variable magnetic field. To minimize noise, the output of the SQUID under test is preamplified by a SQUID series array which is operated at 4.2 K. First results of the characterisation of micro and nano SQUIDs will be presented.

  3. The use of (double) relaxation oscillation SQUIDs as a sensor

    NARCIS (Netherlands)

    van Duuren, M.J.; Brons, G.C.S.; Kattouw, H.; Flokstra, Jakob; Rogalla, Horst

    1997-01-01

    Relaxation Oscillation SQUIDs (ROSs) and Double Relaxation Oscillation SQUIDs (DROSs) are based on relaxation oscillations that are induced in hysteretic dc SQUIDs by an external L-R shunt. The relaxation frequency of a ROS varies with the applied flux Φ, whereas the output of a DROS is a dc

  4. Low noise niobium dc SQUID with a planar input coil

    Energy Technology Data Exchange (ETDEWEB)

    de Waal, V.J.; van den Hamer, P.; Klapwijk, T.M.

    1983-02-15

    A practical all-niobium dc superconducting quantum interference device (SQUID) with a niobium spiral input coil has been developed. The SQUID utilizes submicron Josephson junctions. The best intrinsic energy resolution obtained with a 1-nH SQUID is 4 x 10/sup -32/ J/Hz. A 20-turn 1.2-..mu..H input coil is coupled to a 2.3-nH SQUID with an efficiency of 0.5. The energy resolution with respect to the coil is 1 x 10/sup -30/ J/Hz.

  5. Design consideration for dc SQUIDs fabricated in deep sub-micron technology

    International Nuclear Information System (INIS)

    Ketchen, M.B.

    1991-01-01

    Design rules for scaling dc SQUID junctions to optimize SQUID performance have been well known for over a decade, and verified down to the sub-micron regime. Practical SQUIDs having well coupled input coils of usable inductance have generally been fabricated at the 2-5 μm level of lithography. Other technologies, silicon in particular, are now routinely practiced at the 0.5 μm level of lithography with impressive demonstrations at the 0.1-0.25 μm level not uncommon. In this paper the implications of applying such fabrication capability to advance dc SQUID technology are explored. In particular the issues of scaling practical dc SQUIDs down to the 0.1-0.25 μm regime are examined, using as a prototype design the basic washer SQUID with a spiral input coil

  6. The chokka squid Loligo vulgaris reynaudii is widely distributed ...

    African Journals Online (AJOL)

    spamer

    Department of Mathematics and Applied Mathematics, University of Cape Town, ... The approach .... value of the threshold in the stock-recruit relation- ... for the residuals and adding a “new” residual to each .... effective spawning biomass based on the morphological .... case, current effort is well below the level generating.

  7. High-performance DC SQUIDs with submicrometer niobium Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    de Waal, V.J.; Klapwijk, T.M.; van den Hamer, P.

    1983-11-01

    We report on the fabrication and performance of low-noise, all-niobium, thin-film planar dc SQUIDs with submicrometer Josephson junctions. The junctions are evaporated obliquely through a metal shadow evaporation mask, which is made using optical lithography with 0.5 ..mu..m tolerance. The Josephson junction barrier is formed by evaporating a thin silicon film and with a subsequent oxidation in a glow discharge. The junction parameters can be reproduced within a factor of two. Typical critical currents of the SQUIDs are about 3 ..mu..A and the resistances are about 100 ..cap omega... With SQUIDs having an inductance of 1 nH the voltage modulation is a least 60 ..mu..V. An intrinsic energy resolution of 4 x 10/sup -32/ J/Hz has been reached. The SQUIDs are coupled to wire-wound input coils or with thin-film input coils. The thin-film input coil consists of a niobium spiral of 20 turns on a separate substrate. In both cases the coil is glued onto a 2-nH SQUID with a coupling efficiency of at least 0.5. Referred to the thin-film input coil, the best coupled energy resolution achieved is 1.2 x 10/sup -30/ J/Hz measured in a flux-locked loop at frequencies above 10 Hz. As far as we know, this is the best figure achieved with an all-refractory-metal thin-film SQUID. The fabrication technique used is suited for making circuits with SQUID and pickup coil on the same substrate. We describe a compact, planar, first-order gradiometer integrated with a SQUID on a single substrate. The gradient noise of this device is 3 x 10/sup -12/ Tm/sup -1/. The gradiometer has a size of 12 mm x 17 mm, is simple to fabricate, an is suitable for biomedical applications.

  8. High-performance dc SQUIDs with submicrometer niobium Josephson junctions

    Science.gov (United States)

    de Waal, V. J.; Klapwijk, T. M.; van den Hamer, P.

    1983-11-01

    We report on the fabrication and performance of low-noise, all-niobium, thin-film planar dc SQUIDs with submicrometer Josephson junctions. The junctions are evaporated obliquely through a metal shadow evaporation mask, which is made using optical lithography with 0.5 µm tolerance. The Josephson junction barrier is formed by evaporating a thin silicon film and with a subsequent oxidation in a glow discharge. The junction parameters can be reproduced within a factor of two. Typical critical currents of the SQUIDs are about 3 µA and the resistances are about 100 Ω. With SQUIDs having an inductance of 1 nH the voltage modulation is at least 60 µV. An intrinsic energy resolution of 4×10-32 J/Hz has been reached. The SQUIDs are coupled to wire-wound input coils or with thin-film input coils. The thin-film input coil consists of a niobium spiral of 20 turns on a separate substrate. In both cases the coil is glued onto a 2-nH SQUID with a coupling efficiency of at least 0.5. Referred to the thin-film input coil, the best coupled energy resolution achieved is 1.2×10-30 J/Hz measured in a flux-locked loop at frequencies above 10 Hz. As far as we know, this is the best figure achieved with an all-refractory-metal thin-film SQUID. The fabrication technique used is suited for making circuits with SQUID and pickup coil on the same substrate. We describe a compact, planar, first-order gradiometer integrated with a SQUID on a single substrate. The gradient noise of this device is 3×10-12 T m-1. The gradiometer has a size of 12 mm×17 mm, is simple to fabricate, and is suitable for biomedical applications.

  9. SQUID magnetometry from nanometer to centimeter length scales

    International Nuclear Information System (INIS)

    Hatridge, Michael J.

    2010-01-01

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  10. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

    Hatridge, Michael J. [Univ. of California, Berkeley, CA (United States)

    2010-06-01

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  11. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    Science.gov (United States)

    Chesca, Boris; John, Daniel; Mellor, Christopher J.

    2015-10-01

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise SΦ1/2 decreases as 1/N1/2. Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa2Cu3O7. Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for SΦ1/2 between (0.25 and 0.44) μΦ0/Hz1/2 for temperatures in the range (77-83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10-17) mV and (0.3-2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications.

  12. Preliminary report on the PIXE analysis of the squid statoliths

    International Nuclear Information System (INIS)

    Ikeda, Yuzuru; Arai, Nobuaki; Sakamoto, Wataru; Murayama, Tatsuro; Maeda, Kuniko; Yoshida, Koji.

    1996-01-01

    Micro trace elements in the squid statolith, a calcareous stone which acts as a balancer and hearing, was analyzed with Particle Induced X-ray Emission (PIXE) for the Japanese common squid for the first time. Calcium is the main component of the squid statoliths, which means that squid statolith is the pure calcified structure similar to the fish otolith. Beside Ca, Sr was detected with strong dosage, and some other elements as Mn, Fe, Cu, Zn and As were also detected. Possible assumption of intake of microelements to the statoliths and the suitability of PIXE for statoliths analysis are discussed. (author)

  13. SISTEM OTENTIKASI UNTUK SQUID BERBASIS WEB

    Directory of Open Access Journals (Sweden)

    Febriliyan Samopa

    2006-07-01

    Full Text Available Dalam sebuah jaringan komputer terdapat bermacam-macam tipe user dengan berbagi tingkatan yang berbeda yang juga dibutuhkan perlakuan yang berbeda pada tiap user yang disesuaikan dengan kebutuhan dalam menggunakan akses web, baik berupa http, ftp, gopher, dan lain-lain. Dimana masing-masing user memiliki skala prioritas dalam penggunaan bandwidth, jumlah koneksi maksimum, waktu koneksi, ukuran file maksimum, situs yang tidak boleh diakses dan lain-lain. Tujuan dari penelitian ini adalah membuat sebuah perangkat lunak yang dapat melakukan otentikasi user berdasarkan data konfigurasi yang disimpan dalam basisdata. Selain itu, perangkat lunak yang dibuat dapat memproses request dari client berdasarkan data konfigurasi dengan lebih cepat. Permasalahan yang mucul adalah bagaimana merancang dan membuat suatu perangkat lunak yang dapat melakukan otentikasi user berdasarkan data konfigurasi yang diambil dari basisdata, serta dapat memproses request dari client dengan lebih cepat berdasarkan hak akses yang dimilikinya.Dalam penelitian ini didesain dan diimplementasikan suatu sistem otentikasi user dengan mengambil data user yang tersimpan dalam basisdata MySQL. Disamping itu, dilakukan rekayasa pada beberapa rutin proses yang terdapat dalam squid proxy, supaya proses-proses dapat melakukan pengambilan data konfigurasi yang dialihkan dan disimpan dalam basisdata MySQL. Data konfigurasi ini didasarkan pada pembagian hak akses yang dimiliki oleh masing-masing grup user. Antarmuka berbasis web digunakan sebagai salah satu layanan bagi admin untuk mempermudah pengelolaan dan pengolahan data konfigurasi yang dibuat.Berdasarkan uji coba yang telah dilakukan, terbukti sistem yang dibuat dapat bekerja dengan baik dan tidak melenceng dari fungsi asli sebelum dilakukan perubahan. Bahkan pada penanganan request client yang berukuran besar, kinerja squid mengalami peningkatan dalam hal kecepatan proses yang dibutuhkan. Sebagai contoh, request client pada  file

  14. Negative inductance SQUID qubit operating in a quantum regime

    Science.gov (United States)

    Liu, W. Y.; Su, F. F.; Xu, H. K.; Li, Z. Y.; Tian, Ye; Zhu, X. B.; Lu, Li; Han, Siyuan; Zhao, S. P.

    2018-04-01

    Two-junction SQUIDs with negative mutual inductance between their two arms, called nSQUIDs, have been proposed for significantly improving quantum information transfer but their quantum nature has not been experimentally demonstrated. We have designed, fabricated, and characterized superconducting nSQUID qubits. Our results provide clear evidence of the quantum coherence of the device, whose properties are well described by theoretical calculations using parameters determined from spectroscopic measurement. In addition to their future application for fast quantum information transfer, the nSQUID qubits exhibit rich characteristics in their tunable two-dimensional (2D) potentials, energy levels, wave function symmetries, and dipole matrix elements, which are essential to the study of a wide variety of macroscopic quantum phenomena such as tunneling in 2D potential landscapes.

  15. Drag force and jet propulsion investigation of a swimming squid

    Directory of Open Access Journals (Sweden)

    Tabatabaei Mahdi

    2015-01-01

    Full Text Available In this study, CAD model of a squid was obtained by taking computer tomography images of a real squid. The model later placed into a computational domain to calculate drag force and performance of jet propulsion. The drag study was performed on the CAD model so that drag force subjected to real squid was revealed at squid’s different swimming speeds and comparison has been made with other underwater creatures (e.g., a dolphin, sea lion and penguin. The drag coefficient (referenced to total wetted surface area of squid is 0.0042 at Reynolds number 1.6x106 that is a %4.5 difference from Gentoo penguin. Besides, jet flow of squid was simulated to observe the flow region generated in the 2D domain utilizing dynamic mesh method to mimic the movement of squid’s mantle cavity.

  16. Robot-arm-based mobile HTS SQUID system for NDE of structures

    Energy Technology Data Exchange (ETDEWEB)

    Yotsugi, K; Hatsukade, Y; Tanaka, S [Department of Ecological Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tenpaku-cho, Toyohashi, Aichi 441-8580 (Japan)], E-mail: hatukade@eco.tut.ac.jp

    2008-02-01

    A robot-arm-based mobile HTS SQUID system was developed for NDE of fixed targets. To realize the system, active magnetic shielding technique using fluxgate as reference sensor for ambient field was applied to a cryocooler-based HTS SQUID gradiometer that was mounted on commercial robot-arm. In this technique, ambient field noise and pulse noise of 550 nT from robot were measured by the fluxgate near the SQUID, and then the fluxgate output was negatively fed back to generate compensation field around the SQUID and fluxgate. The noise from robot was reduced by a factor of about 20 and the shielding technique enabled the HTS SQUID to move in unshielded environment by the robot-arm without flux-trapping or unlocking at 10 mm/s. System noise measurement and inspection of hidden cracks in multi-layer composite-metal structure were demonstrated using the mobile SQUID-NDE system.

  17. Well coupled, low noise, dc SQUIDS

    International Nuclear Information System (INIS)

    Muhlfelder, B.; Beall, J.A.; Cromar, M.W.; Johnson, W.W.; Ono, R.H.

    1985-01-01

    The authors have designed, fabricated, and tested a Double Transformer (DT) coupled dc SQUID (Superconducting Quantum Interference Device) with low noise, an input inductance of 1μH and a smooth input-output characteristic. A transmission line model is presented to explain a resonance in the input-output characteristic of early versions of this device. Guided by the results of numerical simulations a new version of this device has been built and tested. Experimental results are presented that show that the resonance can be moved to a higher voltage by reducing the area of the SQUID loop. The voltage-external flux characteristic of some of these new devices agrees to within 10% with computer simulations. The minimum detectable energy per unit bandwidth (MDE) referred to the SQUID loop, is 10h, where h is Planck's constant. Computer simulations indicate an MDE of 6h

  18. SQUIDs in thermal detectors of weakly interacting particles

    International Nuclear Information System (INIS)

    Trofimov, V.N.

    1991-01-01

    The application of four different types of SQUID-assisted thermometers for cryogenic thermal detectors of weakly interacting particles is analyzed with two of them for the first time. The classic resistive thermometer is considered as well for the comparison. Original results of testing the detector with working temperature of 1K and thermocouple thermometer with SQUID are given. The conclusion is made that temperature resolution of 10 -10 kHz -1/2 or energy sensitivity of 1-10 eV per 1 kg of detector mass can be achieved when using the SQUID-assisted thermometers. 12 refs.; 7 figs.; 1 tab

  19. Universal mechanisms of decoherence of qubit states in a SQUID

    Science.gov (United States)

    Kuklov, A. B.; Chudnovsky, E. M.

    2003-03-01

    Fundamental conservation laws mandate parameter-free generic mechanisms of decoherence of quantum oscillations of the superconducting current in a SQUID [1]. The very fact that the current flows with respect to the ion lattice is shown to result in a decoherence via emission of the transverse sound at the oscillation frequency. For SQUIDs larger than the wavelength of the phonons, this effect can significantly limit the quality factor. The decohering effects of the external mechanical and magnetic noise are shown to be proportional to the total magnetic moment of the SQUID, making small SQUIDs less susceptible to the noise than large SQUIDs. Decoherence due to the emission of photons into the open space and in the presence of the metal shielding has been studied as well. Suggestions of experimental setups with low decoherence have been made. [1] E. M. Chudnovsky and A. B. Kuklov, arXiv:cond-mat/0211246.

  20. 75 FR 5537 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2010-02-03

    ...://www.nero.noaa.gov . FOR FURTHER INFORMATION CONTACT: Carrie Nordeen, Fishery Policy Analyst, 978-281... of the initial optimum yield (IOY), allowable biological catch (ABC), domestic annual harvest (DAH... Year Specifications Loligo Illex Mackerel Butterfish Max OY 32,000 24,000 N/A 12,175 [[Page 5538

  1. Market Squid Ecology Dataset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains ecological information collected on the major adult spawning and juvenile habitats of market squid off California and the US Pacific Northwest....

  2. Market Squid Population Dynamics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains population dynamics data on paralarvae, juvenile and adult market squid collected off California and the US Pacific Northwest. These data were...

  3. Characteristics of an HTS-SQUID gradiometer with ramp-edge Josephson junctions and its application on robot-based 3D-mobile compact SQUID NDE system

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukade, Y., E-mail: hatukade@ens.tut.ac.jp [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Hayashi, K.; Shinyama, Y.; Kobayashi, Y. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Adachi, S.; Tanabe, K. [International Superconductivity Technology Center/Superconductivity Research Laboratory, 10-13, Shinonome 1-chome, Koto-ku, Tokyo 135-0062 (Japan); Tanaka, S. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2011-11-15

    We investigated behavior of HTS-dc-SQUID gradiometers with ramp-edge Josephson junctions (JJs) in ac and dc magnetic fields. In the both fields, the gradiometers show higher durability against entry of flux vortices than SQUIDs with bicrystal JJs. A robot-based SQUID NDE system utilizing the gradiometer was developed in an unshielded environment. Detectability of the system to detect non-through cracks in double-layer structures was demonstrated. A new excitation coil was applied to detect cracks that oriented vertical and parallel to the baseline of the gradiometer. In this paper, we investigated detailed behavior of novel HTS-dc-SQUID gradiometers with ramp-edge Josephson junctions (JJs) in both an ac magnetic field and a dc magnetic field. In the both fields, the novel gradiometers shows the superior performance to the conventional YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) HTS-dc-SQUID gradiometer and a bare HTS-dc-SQUID ring with bicrystal JJs concerning durability against entry and hopping of flux vortices, probably due to their differential pickup coils without a grain boundary and multilayer structure of the ramp-edge JJs. A robot-based compact HTS-SQUID NDE system utilizing the novel gradiometer was reviewed, and detectability of the system to detect non-through cracks in a carbon fiber reinforced plastic (CFRP)/Al double-layer structure was demonstrated. A new excitation coil in which the supplied currents flowed in the orthogonal directions was applied to detect cracks that oriented vertical and parallel to the baseline of the gradiometer.

  4. High-Tc SQUIDs: Noise and applications

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hsiao-Mei [Univ. of Houston, TX (United States)

    2001-08-01

    A major challenge in the design and operation of high transition temperature (Tc ) Superconducting Quantum Interference Devices (SQUIDs) is their potential to exhibit substantially higher levels of noise at low frequency f when exposed to earth’s magnetic field. To investigate this problem, we studied the noise of high-Tc SQUIDs, directly coupled magnetometers and multilayer magnetometers in both static and changing magnetic fields. The directly coupled magnetometer consists of a dc SQUID connected to a large area pickup loop in parallel. The multilayer magnetometer involves a multiturn flux transformer inductively coupled to a dc SQUID on a separate substrate. All the devices are made of thin films of the high-Tc superconductor YBa2Cu3O7-δ, patterned into 4 μm linewidths. After cooling in a magnetic field, the devices showed no increase in 1/f noise for fields up to threshold values well above the earth’s magnetic field. The devices were also cooled in a magnetic field that was subsequently turned off. The 1/f noise of bare SQUIDs was unchanged for fields up to 12 μT. The addition of the flux transformer containing flux dams increased the sensitivity to magnetic field by a factor of 43 while reducing the threshold field only moderately, to 5 μT. This result implies that the multilayer magnetometer can be rotated in the earth’s magnetic field through an angle of up to 26o without increasing the low frequency noise. The results of these studies were incorporated into a 5-channel high-Tc magnetocardiography system involving two first-derivative SQUID gradiometers and three reference SQUIDs. Each planar gradiometer consists of a directly coupled SQUID magnetometer inductively coupled to the smaller coil of an asymmetric, two-loop flux transformer. The reference SQUIDs are patterned into 4 μm lines. The outputs of the five channels were subtracted in software to form a second-derivative gradiometer. Its

  5. Sensitive YBCO nanoSQUIDs for the investigation of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Benedikt; Schwarz, Tobias; Woelbing, Roman; Martinez-Perez, Maria Jose; Kleiner, Reinhold; Koelle, Dieter [Tuebingen Univ. (Germany). Physikalisches Inst. and Center for Collective Quantum Phenomena in LISA+; Reiche, Christopher F.; Muehl, Thomas; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany)

    2015-07-01

    We report on advances in the realization of dc YBCO nanoSQUIDs for continuous measurement of magnetic nanoparticle magnetization loops in strong magnetic fields up to the Tesla range, applied in the plane of the SQUID loop at temperatures of 4 K and below. Our grain boundary junction based YBCO SQUIDs are patterned by focused ion beam milling and feature a constriction next to the SQUID loop, allowing for on-chip SQUID modulation and bias reversal readout schemes. Using numerical simulations based on London theory, the spin sensitivity S{sub μ}{sup 1/2} = S{sub Φ}{sup 1/2} / φ{sub μ} was improved by optimizing both the flux noise S{sub Φ}{sup 1/2} and the coupling factor φ{sub μ} = Φ / μ (Φ is the magnetic flux coupled into the SQUID loop by a particle with magnetic moment μ). For optimized experimental devices, flux noise levels down to 50 nΦ{sub 0} / Hz{sup 1/2} in the white noise limit have been achieved, corresponding to a calculated spin sensitivity of only a few μ{sub B} / Hz{sup 1/2}. Further, the magnetization reversal of a Fe filled carbon nanotube attached to a YBCO nanoSQUID was traced out.

  6. Trophic niche of squids: Insights from isotopic data in marine systems worldwide

    Science.gov (United States)

    Navarro, Joan; Coll, Marta; Somes, Christoper J.; Olson, Robert J.

    2013-10-01

    Cephalopods are an important prey resource for fishes, seabirds, and marine mammals, and are also voracious predators on crustaceans, fishes, squid and zooplankton. Because of their high feeding rates and abundance, squids have the potential to exert control on the recruitment of commercially important fishes. In this review, we synthesize the available information for two intrinsic markers (δ15N and δ13C isotopic values) in squids for all oceans and several types of ecosystems to obtain a global view of the trophic niches of squids in marine ecosystems. In particular, we aimed to examine whether the trophic positions and trophic widths of squid species vary among oceans and ecosystem types. To correctly compare across systems, we adjusted squid δ15N values for the isotopic variability of phytoplankton at the base of the food web provided by an ocean circulation-biogeochemistry-isotope model. Studies that focused on the trophic ecology of squids using isotopic techniques were few, and most of the information on squids was from studies on their predators. Our results showed that squids occupy a large range of trophic positions and exploit a large range of trophic resources, reflecting the versatility of their feeding behavior and confirming conclusions from food-web models. Clear differences in both trophic position and trophic width were found among oceans and ecosystem types. The study also reinforces the importance of considering the natural variation in isotopic values when comparing the isotopic values of consumers inhabiting different ecosystems.

  7. SQUIDs De-fluxing Using a Decaying AC Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Matlashov, Andrei Nikolaevich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Semenov, Vasili Kirilovich [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Anderson, Bill [Senior Scientific, LLC, Albuquerque, NM (United States)

    2016-06-08

    Flux trapping is the Achilles’ heel of all superconductor electronics. The most direct way to avoid flux trapping is a prevention of superconductor circuits from exposure to magnetic fields. Unfortunately this is not feasible if the circuits must be exposed to a strong DC magnetic field even for a short period of time. For example, such unavoidable exposures take place in superparamagnetic relaxation measurements (SPMR) and ultra-low field magnetic resonance imaging (ULF MRI) using unshielded thin-film SQUID-based gradiometers. Unshielded SQUIDs stop working after being exposed to DC magnetic fields of only a few Gauss in strength. In this paper we present experimental results with de-fluxing of planar thin-film LTS SQUID-based gradiometers using a strong decaying AC magnetic field. We used four commercial G136 gradiometers for SPMR measurements with up to a 10 mT magnetizing field. Strong 12.9 kHz decaying magnetic field pulses reliably return SQUIDs to normal operation 50 ms after zeroing the DC magnetizing field. This new AC de-fluxing method was also successfully tested with seven other different types of LTS SQUID sensors and has been shown to dissipate extremely low energy.

  8. Summer at the beach: spatio-temporal patterns of white shark occurrence along the inshore areas of False Bay, South Africa.

    Science.gov (United States)

    Kock, Alison A; Photopoulou, Theoni; Durbach, Ian; Mauff, Katya; Meÿer, Michael; Kotze, Deon; Griffiths, Charles L; O'Riain, M Justin

    2018-01-01

    Understanding white shark ( Carcharodon carcharias ) habitat use in coastal areas adjacent to large cities, is an important step when formulating potential solutions to the conservation conflict that exists between humans and large predatory sharks. In this study, we present the findings of a 2.5-year study of white shark occurrence and movement patterns adjacent to the City of Cape Town in False Bay, South Africa, with a focus on spring and summer months. Fifty-one white sharks were monitored annually at three offshore and twelve inshore sites by VR2 acoustic receivers, over 975 days from 1 May 2005 to 31 December 2007. Occurrence patterns at inshore sites during spring and summer were analysed using a generalized additive mixed model (GAMM) with a spatial term (longitude, latitude), time of day and year included as explanatory variables for site use. We found that sharks occurred more frequently at inshore sites along the northern and northwestern shores, compared to the rest of the bay, and they transitioned most frequently between four adjacent beach sites that encompass the most popular recreational water use areas in Cape Town. There was significant diel variation, with higher shark occurrence around midday, and a peak in shark occurrence in 2005, when human-shark interactions also peaked. However, we found no effect of shark size on occurrence patterns at inshore sites. White sharks showed the highest levels of occurrence at specific inshore sites between Muizenberg and Strandfontein beach, and thus inclusion of these sites within False Bay's marine protected area (MPA) network or recognition as Ecological or Biological Significant Areas (EBSAs) should be a future consideration. These insights into white shark habitat use at inshore sites in False Bay are important for successfully applying the principles of marine spatial planning (MSP) and for making science-based policy decisions. Furthermore, this information can be used to reduce potential shark

  9. Inshore small-mesh trawling survey of the Cape south coast. Part 5 ...

    African Journals Online (AJOL)

    Inshore small-mesh trawling survey of the Cape south coast. Part 5. Crustacea, Stomatopoda, Isopoda and. Decapoda. B. Kensley and C.D. Buxton. Port Elizabeth Museum, Port Elizabeth. Forty-six species of Crustacea from the shallow marine waters of the southern Cape coast are listed. Five new records for the area.

  10. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    International Nuclear Information System (INIS)

    Chesca, Boris; John, Daniel; Mellor, Christopher J.

    2015-01-01

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise S Φ 1/2 decreases as 1/N 1/2 . Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa 2 Cu 3 O 7 . Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for S Φ 1/2 between (0.25 and 0.44) μΦ 0 /Hz 1/2 for temperatures in the range (77–83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10–17) mV and (0.3–2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications

  11. Mismatch between the eye and the optic lobe in the giant squid.

    Science.gov (United States)

    Liu, Yung-Chieh; Liu, Tsung-Han; Yu, Chun-Chieh; Su, Chia-Hao; Chiao, Chuan-Chin

    2017-07-01

    Giant squids ( Architeuthis ) are a legendary species among the cephalopods. They live in the deep sea and are well known for their enormous body and giant eyes. It has been suggested that their giant eyes are not adapted for the detection of either mates or prey at distance, but rather are best suited for monitoring very large predators, such as sperm whales, at distances exceeding 120 m and at a depth below 600 m (Nilsson et al. 2012 Curr. Biol. 22 , 683-688. (doi:10.1016/j.cub.2012.02.031)). However, it is not clear how the brain of giant squids processes visual information. In this study, the optic lobe of a giant squid ( Architeuthis dux , male, mantle length 89 cm), which was caught by local fishermen off the northeastern coast of Taiwan, was scanned using high-resolution magnetic resonance imaging in order to examine its internal structure. It was evident that the volume ratio of the optic lobe to the eye in the giant squid is much smaller than that in the oval squid ( Sepioteuthis lessoniana ) and the cuttlefish ( Sepia pharaonis ). Furthermore, the cell density in the cortex of the optic lobe is significantly higher in the giant squid than in oval squids and cuttlefish, with the relative thickness of the cortex being much larger in Architeuthis optic lobe than in cuttlefish. This indicates that the relative size of the medulla of the optic lobe in the giant squid is disproportionally smaller compared with these two cephalopod species. This morphological study of the giant squid brain, though limited only to the optic lobe, provides the first evidence to support that the optic lobe cortex, the visual information processing area in cephalopods, is well developed in the giant squid. In comparison, the optic lobe medulla, the visuomotor integration centre in cephalopods, is much less developed in the giant squid than other species. This finding suggests that, despite the giant eye and a full-fledged cortex within the optic lobe, the brain of giant

  12. Robotic 3D SQUID imaging system for practical nondestructive evaluation applications

    International Nuclear Information System (INIS)

    Isawa, K.; Nakayama, S.; Ikeda, M.; Takagi, S.; Tosaka, S.; Kasai, N.

    2005-01-01

    A robotic three-dimensional (3D) scanning superconducting quantum interference device (SQUID) imaging system was developed for practical nondestructive evaluation (NDE) applications. The major feature of this SQUID-NDE system is that the SQUID sensor itself scans in 3D by traveling over the surface of an object during testing without the need for magnetic shielding. This imaging system consists of (i) DC-SQUID gradiometer for effective movement of the sensor, (ii) SQUID sensor manipulator utilizing an articulated-type robot used in industry, (iii) laser charge-coupled-device (CCD) displacement sensor to measure the 3D coordinates of points on the surface of the object, and (iv) computer-aided numerical interpolation scheme for 3D surface reconstruction of the object. The applicability of this system for NDE was demonstrated by successfully detecting artificial damage of cylindrical-shaped steel tubes

  13. Temperature dependence of the effective sensing area of high-Tc dc SQUIDs

    International Nuclear Information System (INIS)

    Brake, H.J.M. ter; Aarnink, W.A.M.; Bosch, P.J. van den; Hilgenkamp, J.W.M.; Flokstra, J.; Rogalla, H.

    1997-01-01

    The effective sensing area of a high-T c dc SQUID depends on temperature. As a consequence, fluctuations in the operating temperature result in apparent magnetic field noise if the SQUID is placed in a background magnetic field. An analysis of this effect for two SQUID types, the square-washer 'Ketchen' type and the inductively shunted type, is performed. For magnetocardiography, the temperature fluctuations (peak to peak) of the latter SQUID type should be below w 0.3 mK at 77 K, and below 2 mK at 55 K, with an earth's field suppression of 40 dB. For the square-washer SQUID the requirements are about 8 times less stringent. (author)

  14. Fundamental characteristics of the QFP measured by the dc SQUID

    International Nuclear Information System (INIS)

    Shimizu, N.; Harada, Y.; Miyamoto, N.; Hosoya, M.; Goto, E.

    1989-01-01

    This paper describes the fundamental characteristics of the Quantum Flux Parametron (QFP) measured by a new method in which the output signals of the QFP are detected with a dc SQUID. The dc SQUID linearly and continuously converts the output current of the QFP to voltage, allowing the output signal of the QFP to be measured as the voltage of the dc SQUID. Thus, the fundamental characteristics of the QFP have been experimentally confirmed in detail

  15. Observations on inshore and pelagic Dolphins on the South-Eastern Cape coast of South Africa

    Directory of Open Access Journals (Sweden)

    G. S Saayman

    1972-12-01

    Full Text Available The occurrence, size and seaward distribution of schools of inshore and pelagic dolphins is described for three study areas on the south-eastern Cape coast (Algoa Bay; the Tsitsikama Coastal National Park and Plettenberg Bay. Inshore dolphins {Tursiops and Sousa sp. frequented the coastline in relatively small schools whereas pelagic dolphins {Delphinus delphis and Stenella caeruleoalba occurred in very large schools far out to sea. Different ecological zones were used by Sousa for feeding and for social behaviour and maintenance activities. The frequency of occurrence of Sousa at Plettenberg Bay was not affected by seasonal fluctuations in sea surface temperatures. The role of dolphins as predators and their implication in the regulation of the ecosystem of the Tsitsikama Coastal National Park is discussed.

  16. A SQUID Bootstrap Circuit with a Large Parameter Tolerance

    International Nuclear Information System (INIS)

    Zhang Guo-Feng; Kong Xiang-Yan; Xie Xiao-Ming; Zhang Yi; Krause Hans-Joachim; Offenhäusser Andreas

    2013-01-01

    The voltage biased (SQUID) bootstrap circuit (SBC) was recently introduced as an effective means to reduce the preamplifier noise contribution. We analyze the tolerances of the SBC noise suppression performance to spreads in SQUID and SBC circuit parameters. It is found that the tolerance to spread mainly caused by the integrated circuit fabrication process could be extended by a one-time adjustable current feedback. A helium-cooled niobium SQUID with a loop inductance of 350 pH is employed to experimentally verify the analysis. From this work, design criteria for fully integrated SBC devices with a high yield can be derived

  17. 76 FR 45742 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-08-01

    ... mackerel; an update to essential fish habitat (EFH) designations for all life stages of mackerel, Loligo... limited access fisheries; Establish a 10-percent maximum volumetric fish hold upgrade for Tier 1 and Tier... fishery that occurs prior to June 1, vessels issued a mackerel permit may not fish for, possess, or land...

  18. Measurements of the dynamic input impedance of a dc SQUID

    International Nuclear Information System (INIS)

    Hilbert, C.; Clarke, J.

    1985-01-01

    The impedance of a circuit coupled magnetically via a mutual inductance M/sub i/ to a dc SQUID of geometric inductance L is modified by the dynamic input impedance of the SQUID, which can be characterized by the flux-to-current transfer function J/sub Phi/approx. =partialJ/partialPhi; J is the current circulating in the SQUID loop and ∫ is the flux applied to the loop. At the same time, the SQUID is modified by the presence of the input circuit in the lumped circuit approximation, one expects its inductance to be reduced to L'(1-α/sub e/ 2 )L, where α/sub e/ is an effective coupling coefficient. Calculations of J/sub Phi/ using an analog simulator are described and presented in the form of a dynamic inductance L and a dynamic resistance R versus bias current I and Phi. Experimental measurements of L and R were made on a planar, thin-film SQUID tightly coupled to a spiral input coil that was connected in series with a capacitor C/sub i/ to form a resonant circuit. Thus, J/sub Phi/ was determined from the change in the resonant frequency and quality factor of this circuit as a function of I and Phi. At low bias currents (low Josephson frequencies) the measured values of L were in reasonable agreement with values simulated for the reduced SQUID, while at higher bias currents (higher Josephson frequencies) the measured values were in better agreement with values simulated for the unscreened SQUID. Similar conclusions were reached in the comparison of the experimental and simulated values of the flux-to-voltage transfer function V/sub Phi/

  19. A SQUID gradiometer module with wire-wound pickup antenna and integrated voltage feedback circuit

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Guofeng [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yi, E-mail: y.zhang@fz-juelich.de [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Zhang Shulin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Krause, Hans-Joachim [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); and others

    2012-10-15

    The performance of the direct readout schemes for dc SQUID, Additional Positive Feedback (APF), noise cancellation (NC) and SQUID bootstrap circuit (SBC), have been studied in conjunction with planar SQUID magnetometers. In this paper, we examine the NC technique applied to a niobium SQUID gradiometer module with an Nb wire-wound antenna connecting to a dual-loop SQUID chip with an integrated voltage feedback circuit for suppression of the preamplifier noise contribution. The sensitivity of the SQUID gradiometer module is measured to be about 1 fT/(cm {radical}Hz) in the white noise range in a magnetically shielded room. Using such gradiometer, both MCG and MEG signals are recorded.

  20. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    Energy Technology Data Exchange (ETDEWEB)

    Chesca, Boris, E-mail: B.Chesca@lboro.ac.uk; John, Daniel [Department of Physics, Loughborough University, Loughborough LE11 3TU (United Kingdom); Mellor, Christopher J. [School of Physics and Astronomy, Nottingham University, Nottingham NG7 2RD (United Kingdom)

    2015-10-19

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise S{sub Φ}{sup 1/2} decreases as 1/N{sup 1/2}. Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa{sub 2}Cu{sub 3}O{sub 7}. Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for S{sub Φ}{sup 1/2} between (0.25 and 0.44) μΦ{sub 0}/Hz{sup 1/2} for temperatures in the range (77–83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10–17) mV and (0.3–2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications.

  1. On the structure of the inshore fish community of England and Wales

    International Nuclear Information System (INIS)

    Henderson, P.A.

    1988-12-01

    Records of fish captures on power station intake screens were used to analyse the structure of the English and Welsh inshore fish community. The study was undertaken as part of a programme to predict fish captures at future power station sites. It was found that 118 of the 122 fish species known to live inshore were recorded from the screens of only 12 coastal power stations. The minimum number of species at one site was about 80, found at fully marine localities along the English Channel coast. This number declined with increasing latitude and decreasing salinity. On average, 28 species were present simultaneously and these would include four pelagic, eight demersal and 16 benthic species. There was found to be 31 dominant species which comprised greater than 96% of the total catch by weight or number at all of the sites. These can be considered as the key species through which most of the energy and nutrients in the ecosystem must travel. The major factors determining the abundance of these species were salinity, degree of shelter, summer temperatures and winter temperatures. (author)

  2. A method of background noise cancellation for SQUID applications

    International Nuclear Information System (INIS)

    He, D F; Yoshizawa, M

    2003-01-01

    When superconducting quantum inference devices (SQUIDs) operate in low-cost shielding or unshielded environments, the environmental background noise should be reduced to increase the signal-to-noise ratio. In this paper we present a background noise cancellation method based on a spectral subtraction algorithm. We first measure the background noise and estimate the noise spectrum using fast Fourier transform (FFT), then we subtract the spectrum of background noise from that of the observed noisy signal and the signal can be reconstructed by inverse FFT of the subtracted spectrum. With this method, the background noise, especially stationary inferences, can be suppressed well and the signal-to-noise ratio can be increased. Using high-T C radio-frequency SQUID gradiometer and magnetometer, we have measured the magnetic field produced by a watch, which was placed 35 cm under a SQUID. After noise cancellation, the signal-to-noise ratio could be greatly increased. We also used this method to eliminate the vibration noise of a cryocooler SQUID

  3. Symposium on applications of superconducting quantum interference devices (SQUIDS)

    International Nuclear Information System (INIS)

    1978-01-01

    The abstracts are given of thirteen papers presented at a ''SQUID Symposium'' organized by the Division of Materials Sciences of the U.S. Department of Energy and held March 23--25, 1978, at the University of Virginia. Since SQUID systems have already been utilized in feasibility demonstration in geothermal reservoir exploration, it was recognized that these devices also hold great potential for many other important scientific measurements. Many of these are energy-related, and others include forefront investigations in a diverse group of scientific areas, from biomedical to earthquake monitoring. Research in SQUIDs has advanced so rapidly in recent years that it was felt that a symposium to review the current status and future prospects of the devices would be timely. The abstracts given present an overview of work in this area and hopefully provide an opportunity to increase awareness among basic and applied scientists of the inherent implications of the extreme measurement sensitivity in advanced SQUID systems

  4. The low fault HTSL-SQUID cooling system. Final report; Stoerarmes HTSL-SQUID-Kuehlsystem. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Binneberg, A.; Spoerl, G.; Buschmann, H.

    1997-03-01

    In the context of the research project, work was done for HTSL-SQUID on (1) the development of a thermo-siphon cooler (low fault and continuously working) and (2) the development of a latent storage cooler (low fault and discontinuously working). Two development versions of the latent storage cooler were followed up, the development of a spherical latent storage cooler and the development of an annular vessel latent storage cooler. A further precondition for the construction of the cooler was the use of split Stirling refrigerators as units producing the cold. The experimental sample was built up with refrigerators which could produce a nominal cooling output of 1.2 W at 80 K. Two samples of the thermo-siphon cooler were built, tested and improved. The second sample was developed further as a demonstration model, introduced at meetings and prepared for testing the cooling of HTSL-SQUIDs. The thermo-siphon cooler can be designed for cooling output up to about 2 W at 80 K and can be used controlled for a temperature range of 90 K to 66 K. (orig./MM) [Deutsch] Im Rahmen des Forschungsvorhabens wurde fuer HTSL-SQUID`s an der (1) Entwicklung eines Thermosiphon-Kuehlers (stoerarm und kontinuierlich arbeitend) und (2) Entwicklung eines Latentspeicher-Kuehlers (stoerfrei und diskontinuierlich arbeitend) gearbeitet. Bei dem Latentspeicher-Kuehler wurden zwei Entwicklungsversionen verfolgt, und zwar Entwicklung eines Kugel-Latentspeicher-Kuehlers und Entwicklung eines Ringgefaess-Latentspeicher-Kuehlers. Eine weitere Praemisse zum Aufbau der Kuehler war der Einsatz von Split-Stirling-Kaeltemaschinen als kaelteerzeugende Baugruppe. Die Versuchsmuster wurden mit Kaeltemaschinen aufgebaut, die eine Nennkuehlleistung von 1,2 W bei 80 K erzeugen konnten. Der Thermosiphon-Kuehler wurde in zwei Musterexemplaren aufgebaut, erprobt und verbessert. Das Zweitmuster wurde als Demonstrator weiterentwickelt, zu Fachtagungen vorgestellt und zur Testung der Kuehlung von HTSL-SQUIDs

  5. SQUID-based measuring systems

    Indian Academy of Sciences (India)

    field produced by a given two-dimensional current density distribution is inverted using the Fourier transform technique. Keywords ... Superconducting quantum interference devices (SQUIDs) are the most sensitive detectors for measurement of ... omagnetic prospecting, detection of gravity waves etc. Judging the importance ...

  6. Scanning SQUID susceptometers with sub-micron spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Kirtley, John R., E-mail: jkirtley@stanford.edu; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A. [Department of Applied Physics, Stanford University, Stanford, California 94305-4045 (United States); Paulius, Lisa [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States); Spanton, Eric M. [Department of Physics, Stanford University, Stanford, California 94305-4045 (United States); Schiessl, Daniel [Attocube Systems AG, Königinstraße 11A, 80539 Munich (Germany); Jermain, Colin L.; Gibbons, Jonathan [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Fung, Y.-K.K.; Gibson, Gerald W. [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Huber, Martin E. [Department of Physics, University of Colorado Denver, Denver, Colorado 80217-3364 (United States); Ralph, Daniel C. [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States); Ketchen, Mark B. [OcteVue, Hadley, Massachusetts 01035 (United States)

    2016-09-15

    Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ{sub 0}/Hz{sup 1/2}. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

  7. Scanning SQUID susceptometers with sub-micron spatial resolution

    International Nuclear Information System (INIS)

    Kirtley, John R.; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A.; Paulius, Lisa; Spanton, Eric M.; Schiessl, Daniel; Jermain, Colin L.; Gibbons, Jonathan; Fung, Y.-K.K.; Gibson, Gerald W.; Huber, Martin E.; Ralph, Daniel C.; Ketchen, Mark B.

    2016-01-01

    Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ_0/Hz"1"/"2. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

  8. Review of Magneto cardiography Technology based on SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Kwon, H.; Kim, J. M.; Kim, K.; Yu, K. K.; Park, Y. K. [Brain and Cognition Measurement Lab, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2012-04-15

    Electric activity of cardiac muscles generates magnetic fields. Magnetocardiography (or MCG) technology, measuring these magnetic signals, can provide useful information for the diagnosis of heart diseases. It is already about 40 years ago that the first measurement of MCG signals was done by D. Cohen using SQUID (superconducting quantum interference device) sensor inside a magnetically shielded room. In the early period of MCG history, bulky point-contact RF-SQUID was used as the magnetic sensor. Thanks to the development of Nb-based Josephson junction technology in mid 1980s and new design of tightly-coupled DC-SQUID, low-noise SQUID sensors could be developed in late 1980s. In around 1990, several groups developed multi-channel MCG systems and started clinical study. However, it is quite recent years that the true usefulness of MCG was verified in clinical practice, for example, in the diagnosis of coronary artery disease. For the practical MCG system, technical elements of MCG system should be optimized in terms of performance, fabrication cost and operation cost. In this review, development history, technical issue, and future development direction of MCG technology are described.

  9. Correlation between fluxgate and SQUID magnetometer data sets for geomagnetic storms

    Directory of Open Access Journals (Sweden)

    Matladi Thabang

    2014-01-01

    Full Text Available There has always been a need to monitor the near Earth's magnetic field, as this monitoring provides understanding and possible predictions of Space Weather events such as geomagnetic storms. Conventional magnetometers such as fluxgates have been used for decades for Space Weather research. The use of highly sensitive magnetometers such as Superconducting QUantum Interference Devices (SQUIDs, promise to give more insight into Space Weather. SQUIDs are relatively recent types of magnetometers that exploit the superconductive effects of flux quantization and Josephson tunneling to measure magnetic flux. SQUIDs have a very broad bandwidth compared to most conventional magnetometers and can measure magnetic flux as low as a few femtotesla. Since SQUIDs have never been used in Space Weather research, unshielded, it is necessary to investigate if they can be reliable Space Weather instruments. The validation is performed by comparing the frequency content of the SQUID and fluxgate magnetometers, as reported by Phiri.

  10. Noise characteristics of a dc SQUID with a resistively shunted inductance

    International Nuclear Information System (INIS)

    Enpuku, K.; Muta, T.; Yoshida, K.; Irie, F.

    1985-01-01

    Noise characteristics of a dc SQUID with an inductance shunted by a damping resistance are studied numerically. It is shown that the damping resistance improves considerably the resolution of the SQUID in the case of large β, where β = 2LI 0 /Phi 0 , I 0 is a critical current, L is a loop inductance and Phi 0 is the flux quantum. The energy resolutions for β = 4 and β = 10 are only about 2 and 4 times larger than that for β = 1, respectively. Furthermore, the ranges of both the bias current and the external flux, where good resolution is obtained, become very wide compared with the conventional SQUID. Therefore, the SQUID with the damping resistance can be used for large β (or L) without the significant degradation of the resolution, and will much improve the coupling properties between the SQUID and the input circuitry. The numerical simulation results are also compared with analytical ones, and a reasonable agreement is obtained

  11. RF SQUID in the nonhysteretic regime with k2Ql>1

    International Nuclear Information System (INIS)

    Dmitrenko, I.M.; Tsoi, G.M.; Shnyrkov, V.I.; Kartsovnik, V.V.

    1982-01-01

    Experimental measurements of current-voltage, current-phase, amplitude-frequency, phase-frequency, and signal characteristics of an rf SQUID operating at a frequency of 30 MHz in the nonhysteretic regime (1 = 2πL 0 I 0 /phi/sub o/ 2 Ql>1. Here I 0 is the critical current of the weak link, L 0 is the SQUID ring inductance, k is the coefficient of coupling of the SQUID ring to a resonant tank circuit of quality Q, and phi 0 is the magnetic flux quantum. A numerical analysis of the above characteristics for all relevant parameter values close to those occurring under experimental conditions was performed for qualitative comparison with theory. The main difference from the traditional nonhysteretic regime of SQUID operation (k 2 Q1 12 V/Wb for the single-valued region of the signal characteristics. The results suggest that considerable improvement of rf SQUID resolution is possible in the regime k 2 Ql>1

  12. Magnetic shield effect simulation of superconducting film shield covering directly coupled HTS dc-SQUID magnetometer

    International Nuclear Information System (INIS)

    Terauchi, N.; Noguchi, S.; Igarashi, H.

    2011-01-01

    A superconducting film shield over a SQUID ring improves the robustness of the SQUID with respect to magnetic noise. Supercurrent in the SQUID magnetometer and the superconducting film shield were simulated. The superconducting film shield reduces the influence of the external magnetic field on the SQUID ring. An HTS SQUID is a high sensitive magnetic sensor. In recent years, the HTS SQUID is widely used in various applications. In some applications, high robustness with respect to magnetic noise is required to realize stable operation at outside of a magnetic shielding room. The target of this paper is a directly coupled HTS dc-SQUID magnetometer. To enhance the robustness of the SQUID magnetometer, use of a superconducting thin film shield has been proposed. The magnetic field directly penetrating the SQUID ring causes the change of the critical current of Josephson junction, and then the SQUID magnetometer transitions into inoperative state. In order to confirm the magnetic shield effect of the superconducting film shield, electromagnetic field simulation with 3D edge finite element method was performed. To simulate the high temperature superconductor, E-J characteristics and c-axis anisotropy are considered. To evaluate the effect of the superconducting film shield, an external magnetic field which is supposed to be a magnetic noise is applied. From the simulation results, the time transition of the magnetic flux penetrating the SQUID ring is investigated and the effect of the superconducting film shield is confirmed. The amplitude of the magnetic flux penetrating the SQUID ring can be reduced to about one-sixth since the superconducting film shield prevents the magnetic noise from directly penetrating the SQUID ring.

  13. Analysis of Squid Net Fisheries Business Production

    Directory of Open Access Journals (Sweden)

    Herna Octivia Damayanti

    2017-03-01

    Full Text Available Squid net is one of alternatives to replace trawl net in Pati regency. The purposes of the research are 1 to determine the influence factors, 2 to analyze the return to scale, 3 to analyze cost and return.The research location in Juwana Subdistrict particularly Bakaran Kulon, Dukutalit, Bajomulyo and Bendar Villages. The research conducted on October 2015 to June 2016. The number of final samples was 36, while the formulation of management strategies used 15 samples by snowball sampling. Data analysis techniques used 1 Cobb Douglas production function, 2 revenue-cost ratio analysis. The results of the research are 1 significant inputs for production factor are long trip, Solar fuel, the number of crew and lights. 2 the return to scale of squid net bussiness in Juwana subdistrict Pati regency is -0.231 means decreasing to scale. 3 the R/C ratio of scenario II more profitable for squid net crews than  scenario I.

  14. A study of feeding in some inshore reef fish of the Natal Coast, South ...

    African Journals Online (AJOL)

    A detailed quantitative investigation of the feeding habits of seven important Natal inshore ... limits of influence of the surf zone or shore break. The physical features of .... There is a tendency for juvenile N. JithophiJus to form larger shoals than ...

  15. The biomass and ecology of chokka squid Loligo vulgaris reynaudii ...

    African Journals Online (AJOL)

    1991-01-22

    Jan 22, 1991 ... Figure 1 The study area off the West Coast of South Africa. Depth and latitudinal ...... ground in the south of the srudy area unfOrblnately does not allow the .... school segregation between the sexes, and similar sizes schooling ...

  16. Fabrication and characterization of hybrid Nb-YBCO dc SQUIDs

    International Nuclear Information System (INIS)

    Frack, E.K.; Drake, R.E.; Patt, R.; Radparvar, M.

    1991-01-01

    This paper reports on the fabrication of hybrid low T c /high T c dc SQUIDs of two flavors. The first kind utilizes niobium tunnel junctions and a YBCO film strip as the most inductive portion of the SQUID loop. This configuration allows a direct measurement of the inductance of the YBCO microstrip from which the effective penetration depth can be calculated. The successful fabrication of these SQUIDs has required 1. superconducting Nb-to-YBCO contacts, 2. deposition and patterning of an SiO 2 insulation layer over YBCO, and 3. selective patterning of niobium and SiO 2 relative to YBCO. All these process steps are pertinent to the eventual use of YBCO thin films in electronic devices

  17. Integrated de SQUID magnetometer with high dV/dB

    International Nuclear Information System (INIS)

    Drung, D.; Cantor, R.; Peters, M.; Ryhanen, T.; Kochi, H.

    1991-01-01

    This paper presents a directly coupled dc SQUID magnetometer with very simple feedback electronics. The magnetometer has been integrated on a 7.2 x 7.2 mm 2 chip and fabricated using a four-level Nb/Si x N v /Nb process. Eight pick-up loops are connected in parallel to directly form the SQUID inductance of about 0.4 nH which leads to a high sensitivity B/Φ = 0.47 nT/Φ. An Additional Positive Feedback (APF) circuit on the magnetometer chip has been used to increase the gradient of the V-μ characteristic to dV/dΦ ≅ 300 μV/Φ 0 at the SQUID operating point. The resulting gradient of the transfer function of dV/dB ≅ 640 μV/nT makes it possible to directly read out the SQUID without helium temperature impedance matching circuits or flux modulation techniques

  18. Step edge Josephson junctions and high temperature superconducting quantum interference device (SQUID) gradiometers

    International Nuclear Information System (INIS)

    Millar, Alasdair J.

    2002-01-01

    This thesis is concerned with the development of Superconducting Quantum Interference Device (SQUID) gradiometers based on the high temperature superconductor YBa 2 Cu 3 O 7-δ (YBCO). A step-edge Josephson junction fabrication process was developed to produce sufficiently steep (>60 deg) step-edges such that junctions exhibited RSJ-like current-voltage characteristics. The mean I C R N product of a sample of twenty step-edge junctions was 130μV. Step-edge dc SQUIDs with inductances between 67pH and 114pH were fabricated. Generally the SQUIDs had an intrinsic white flux noise in the 10-30μΦ 0 /√Hz range, with the best device, a 70pH SQUID, exhibiting a white flux noise of 5μΦ 0 /√Hz. Different first-order SQUID gradiometer designs were fabricated from single layers of YBCO. Two single-layer gradiometer (SLG) designs were fabricated on 10x10mm 2 substrates. The best balance and lowest gradient sensitivity measured for these devices were 1/300 and 308fT/cm√Hz (at 1 kHz) respectively. The larger baseline and larger flux capture area of the pick-up loops in a large area SLG design, fabricated on 30x10mm 2 substrates, resulted in significant improvements in the balance and gradient field sensitivity with 1/1000 and 50fT/cm√Hz (at 1kHz) measured respectively. To reduce the uniform field effective area of SLOs and therefore reduce the direct pick-up of environmental field noise when operated unshielded, a novel gradiometric SQUID (G-SQUID) device was developed. Fabricated from a single layer of YBCO, the G-SQUIDs with inductances of 67pH, had small uniform field effective areas of approximately 2μm 2 - more than two orders of magnitude smaller than the uniform field effective areas of conventional narrow linewidth SQUIDs of similar inductance. Two designs of G-SQUID were fabricated on 10x10mm 2 substrates. Due to their small effective areas, when cooled unshielded these devices showed no increase in their white flux noise. The best balance achieved for a G-SQUID

  19. Coherent arrays of planar dc-SQUIDS based on thin-film Josephson microbridges

    International Nuclear Information System (INIS)

    Hansen, J.B.

    1982-01-01

    Phase-locking and voltage-locking in systems consisting of two planar dc-SQUIDs located close together in the same superconducting film have been investigated. The locking strength was found to be strongly dependent on the fluxoid state of both SQUIDs. A simple model for the inductive coupling between two such dc-SQUIDs is presented and the prediction of the model is compared with the experimental results. (Auth.)

  20. Site-specific assessments of the abundance of three inshore dolphin species to inform conservation and management

    Directory of Open Access Journals (Sweden)

    Alexander Mark Brown

    2016-02-01

    Full Text Available Assessing the abundance of wildlife populations is essential to their effective conservation and management. Concerns have been raised over the vulnerability of tropical inshore dolphins in waters off northern Australia to anthropogenic impacts on local populations, yet a lack of abundance data precludes assessment of their conservation status and the management of threats. Using small vessels as cost-effective research platforms, photo-identification surveys and capture-recapture models were applied to provide the first quantitative abundance data for Australian snubfin (Orcaella heinsohni, Australian humpback (Sousa sahulensis, and Indo-Pacific bottlenose dolphins (Tursiops aduncus at five sites in the Kimberley region of north-western Australia. The abundance of each species was highly variable between different sites, likely reflecting species-specific habitat preferences. Within the c. 130 km2 study sites, the estimated abundance of most species was ≤ 60 individuals (excluding calves, and fewer than 20 humpback dolphins were identified at each site in any one 3-5 week sampling period. However, larger estimates of c. 130 snubfin and c. 160 bottlenose dolphins were obtained at two different sites. Several local populations showed evidence of site fidelity, particularly snubfin dolphins. By implementing a standardized, multi-site approach, data on local populations were provided within a broader, regional context, and indicated that each species is patchily distributed in the region. This highlights the need for site-specific baseline data collection using appropriate survey techniques to quantitatively assess the potential impacts of threatening activities to local populations. These findings further illustrate the need to gain a greater understanding of known and potential threats to inshore dolphin populations, their relative impacts, and to mitigate where necessary. In particular, the level of interactions with inshore gillnet fisheries

  1. Hot electron effect in the dc SQUID

    International Nuclear Information System (INIS)

    Wellstood, F.C.; Clarke, J.; Urbina, C.

    1989-01-01

    The authors have investigated the temperature dependence of the noise in thin-film dc Superconducting Quantum Interference Devices (SQUIDs) down to 20 mK. The white noise measured in the early versions of our SQUIDs did not decrease as the bath temperature was lowered below 150 mK. They have attributed this saturation to a hot electron effect in the thin-film AuCu resistors shunting the Josephson junctions. A theoretical investigation showed that the temperature of the electrons in the shunts should be given by T/sub e/ = (P/ΣΩ)/sup 1/5/, where P is the power dissipated in the shunts, Ω is the shunt volume, and Σ is a proportionality constant. Experimentally, the authors found Σ=(2.4+-0.6)X10/sup 9/WK/sup -5/m/sup -3/. They have redesigned the shunts, adding large thin-film cooling fins, to increase their volume substantially. This technique has reduced T/sub e/ to about 50 mK, with a corresponding improvement in the sensitivity of the SQUIDs

  2. Directly coupled YBCO dc SQUID magnetometers

    International Nuclear Information System (INIS)

    Petersen, P.R.E.; Shen, Y.Q.; Holst, T.; Larsen, B.H.; Sager, M.P.; Bindslev Hansen, J.

    1999-01-01

    YBa 2 Cu 3 O 7- x magnetometers have been made on 10mmx10mm MgO substrates by directly coupling the magnetometer pick-up loop to a dc SQUID with narrow strip lines. The dc SQUIDs were made with YBa 2 Cu 3 O 7-x step-edge Josephson junctions. The layout of the magnetometer pick-up loop was chosen as a compromise between maximizing the loop effective area and minimizing the loop inductance. The SQUID was designed to have L S ∼100 pH in order to obtain β L =2I 0 L S /Φ 0 approx.= 1 with the single-junction critical current I 0 ∼10 μA. We have made magnetometers with white noise levels down to 55 fT Hz -1/2 and a 1/f knee at 1 Hz (ac biased). Noise measurements were made on a field-cooled magnetometer. The noise measured at 1 Hz when cooled in 'zero field' was 175 fT Hz -1/2 . When cooled in magnetic fields of B = 50 μT and B = 100 μT we measured the noise at 1 Hz to be 430 fT Hz -1 2 and 1.3 pT Hz -1/2 , respectively. (author)

  3. Identification of four squid species by quantitative real-time polymerase chain reaction.

    Science.gov (United States)

    Ye, Jian; Feng, Junli; Liu, Shasha; Zhang, Yanping; Jiang, Xiaona; Dai, Zhiyuan

    2016-02-01

    Squids are distributed worldwide, including many species of commercial importance, and they are often made into varieties of flavor foods. The rapid identification methods for squid species especially their processed products, however, have not been well developed. In this study, quantitative real-time PCR (qPCR) systems based on specific primers and TaqMan probes have been established for rapid and accurate identification of four common squid species (Ommastrephes bartramii, Dosidicus gigas, Illex argentinus, Todarodes pacificus) in Chinese domestic market. After analyzing mitochondrial genes reported in GenBank, the mitochondrial cytochrome b (Cytb) gene was selected for O. bartramii detection, cytochrome c oxidase subunit I (COI) gene for D. gigas and T. Pacificus detection, ATPase subunit 6 (ATPase 6) gene for I. Argentinus detection, and 12S ribosomal RNA (12S rDNA) gene for designing Ommastrephidae-specific primers and probe. As a result, all the TaqMan systems are of good performance, and efficiency of each reaction was calculated by making standard curves. This method could detect target species either in single or mixed squid specimen, and it was applied to identify 12 squid processed products successfully. Thus, it would play an important role in fulfilling labeling regulations and squid fishery control. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. NANO-SQUIDs based on niobium Dayem bridges for nanoscale applications

    Energy Technology Data Exchange (ETDEWEB)

    Granata, C; Esposito, E; Nappi, C; Ruggiero, B; Russo, M [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, 80078 Pozzuoli (Napoli) (Italy); Vettoliere, A; Walke, P [Also Universita degli Studi di Napoli ' Federico II' , Napoli (Italy); Silvestrini, P, E-mail: c.granata@cib.na.cnr.i [Dipartimento di Ingegneria dell' Informazione, Seconda Universita degli Studi di Napoli, Aversa(Caserta) (Italy)

    2010-06-01

    We report on the design, the fabrication and the performance of an integrated magnetic nano-sensor based on niobium dc-SQUID (Superconducting QUantum Interference Device) for nanoscale applications is presented. The nano-sensors are based on nanometric niobium constrictions (Dayem bridges) inserted in a square loop having a side length of 200 nm. Measurements of voltage-flux characteristic, flux to voltage transfer factor and noise performances are reported. In small signal mode, the sensors have shown a magnetic flux noise spectral density of 1.5 {mu}{Phi}{sub 0}/Hz{sup 1/2} corresponding to a spin sensitivity in unit of Bohr magneton of 60 spin/Hz{sup 1/2}. Supercurrent decay measurements of these devices are also reported. Such measurements provide useful information for applications which employ the SQUID as a trigger where the sensor works on the zero voltage state. The experimental data, have shown an intrinsic current fluctuation less than 0.2% of the critical current at liquid helium temperature, corresponding to an intrinsic sensor magnetic flux resolution of a few m{Phi}{sub 0}. In view of the nano-SQUID employments in the detection of small spin populations, the authors calculated the spin sensitivity and the magnetic response relative to the single spin, as a function of its position within the SQUID hole. The results show that the SQUID response depends strongly on the spin position.

  5. Low-frequency flux noise in YBCO dc SQUIDs cooled in static magnetic fields

    International Nuclear Information System (INIS)

    Sager, M.P.; Bindslev Hansen, J.; Petersen, P.R.E.; Holst, T.; Shen, Y.Q.

    1999-01-01

    The low-frequency flux noise in bicrystal and step-edge YBa 2 Cu 3 O x dc SQUIDs has been investigated. The width, w, of the superconducting strips forming the SQUID frame was varied from 4 to 42 μm. The SQUIDs were cooled in static magnetic fields up to 150 μT. Two types of low-frequency noise dominated, namely 1/f-like noise and random telegraph noise giving a Lorentzian frequency spectrum. The 1/f noise performance of the w = 4, 6 and 7 μm SQUIDs was almost identical, while the SQUIDs with w = 22 and 42 μm showed an order of magnitude higher noise level. Our analysis of the data suggests an exponential increase of the 1/f noise versus the cooling field, exhibiting a characteristic magnetic field around 40 μT. (author)

  6. SQUIDs in biomagnetism: a roadmap towards improved healthcare

    Science.gov (United States)

    Körber, Rainer; Storm, Jan-Hendrik; Seton, Hugh; Mäkelä, Jyrki P.; Paetau, Ritva; Parkkonen, Lauri; Pfeiffer, Christoph; Riaz, Bushra; Schneiderman, Justin F.; Dong, Hui; Hwang, Seong-min; You, Lixing; Inglis, Ben; Clarke, John; Espy, Michelle A.; Ilmoniemi, Risto J.; Magnelind, Per E.; Matlashov, Andrei N.; Nieminen, Jaakko O.; Volegov, Petr L.; Zevenhoven, Koos C. J.; Höfner, Nora; Burghoff, Martin; Enpuku, Keiji; Yang, S. Y.; Chieh, Jen-Jei; Knuutila, Jukka; Laine, Petteri; Nenonen, Jukka

    2016-11-01

    Globally, the demand for improved health care delivery while managing escalating costs is a major challenge. Measuring the biomagnetic fields that emanate from the human brain already impacts the treatment of epilepsy, brain tumours and other brain disorders. This roadmap explores how superconducting technologies are poised to impact health care. Biomagnetism is the study of magnetic fields of biological origin. Biomagnetic fields are typically very weak, often in the femtotesla range, making their measurement challenging. The earliest in vivo human measurements were made with room-temperature coils. In 1963, Baule and McFee (1963 Am. Heart J. 55 95-6) reported the magnetic field produced by electric currents in the heart (‘magnetocardiography’), and in 1968, Cohen (1968 Science 161 784-6) described the magnetic field generated by alpha-rhythm currents in the brain (‘magnetoencephalography’). Subsequently, in 1970, Cohen et al (1970 Appl. Phys. Lett. 16 278-80) reported the recording of a magnetocardiogram using a Superconducting QUantum Interference Device (SQUID). Just two years later, in 1972, Cohen (1972 Science 175 664-6) described the use of a SQUID in magnetoencephalography. These last two papers set the scene for applications of SQUIDs in biomagnetism, the subject of this roadmap. The SQUID is a combination of two fundamental properties of superconductors. The first is flux quantization—the fact that the magnetic flux Φ in a closed superconducting loop is quantized in units of the magnetic flux quantum, Φ0 ≡ h/2e, ≈ 2.07 × 10-15 Tm2 (Deaver and Fairbank 1961 Phys. Rev. Lett. 7 43-6, Doll R and Näbauer M 1961 Phys. Rev. Lett. 7 51-2). Here, h is the Planck constant and e the elementary charge. The second property is the Josephson effect, predicted in 1962 by Josephson (1962 Phys. Lett. 1 251-3) and observed by Anderson and Rowell (1963 Phys. Rev. Lett. 10 230-2) in 1963. The Josephson junction consists of two weakly coupled superconductors

  7. Squid-derived chitin oligosaccharides are a chemotactic signal during colonization by Vibrio fischeri.

    Science.gov (United States)

    Mandel, Mark J; Schaefer, Amy L; Brennan, Caitlin A; Heath-Heckman, Elizabeth A C; Deloney-Marino, Cindy R; McFall-Ngai, Margaret J; Ruby, Edward G

    2012-07-01

    Chitin, a polymer of N-acetylglucosamine (GlcNAc), is noted as the second most abundant biopolymer in nature. Chitin serves many functions for marine bacteria in the family Vibrionaceae ("vibrios"), in some instances providing a physical attachment site, inducing natural genetic competence, and serving as an attractant for chemotaxis. The marine luminous bacterium Vibrio fischeri is the specific symbiont in the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes. The bacterium provides the squid with luminescence that the animal uses in an antipredatory defense, while the squid supports the symbiont's nutritional requirements. V. fischeri cells are harvested from seawater during each host generation, and V. fischeri is the only species that can complete this process in nature. Furthermore, chitin is located in squid hemocytes and plays a nutritional role in the symbiosis. We demonstrate here that chitin oligosaccharides produced by the squid host serve as a chemotactic signal for colonizing bacteria. V. fischeri uses the gradient of host chitin to enter the squid light organ duct and colonize the animal. We provide evidence that chitin serves a novel function in an animal-bacterial mutualism, as an animal-produced bacterium-attracting synomone.

  8. Performance of a novel SQUID-based superconducting imaging-surface magnetoencephalography system

    Science.gov (United States)

    Kraus, R. H.; Volegov, P.; Maharajh, K.; Espy, M. A.; Matlashov, A. N.; Flynn, E. R.

    2002-03-01

    Performance for a recently completed whole-head magnetoencephalography system using a superconducting imaging surface (SIS) surrounding an array of 150 SQUID magnetometers is reported. The helmet-like SIS is hemispherical in shape with a brim. Conceptually, the SIS images nearby sources onto the SQUIDs while shielding sensors from distant “noise” sources. A finite element method (FEM) description using the as-built geometry was developed to describe the SIS effect on source fields by imposing B⊥( surface)=0 . Sensors consist of 8×8 mm 2 SQUID magnetometers with 0.84 nT/ Φ0 sensitivity and positions and orientations was found. Good agreement was found between modeled and measured shielding of the SQUIDs from sources external to the array showing significant frequency-independent shielding. Phantom localization precision was better than 0.5 mm at all locations with a mean of better than 0.3 mm.

  9. Non-destructive inspection using HTS-SQUID on aluminum liner covered by CFRP

    International Nuclear Information System (INIS)

    Hatsukade, Y.; Yotsugi, K.; Sakaguchi, Y.; Tanaka, S.

    2007-01-01

    An eddy-current-based SQUID non-destructive inspection (NDI) system to detect deep-lying cracks in multi-layer composite-Al vessels was developed taking advantage of the uncontested sensitivity of HTS-SQUID in low-frequency range. An HTS-SQUID gradiometer was mounted in a pulse tube cryocooler. A pair of differential coils with C-shaped ferrite cores was employed to induce an enhanced eddy current in an Al vessel wrapped in a carbon fiber reinforced plastic (CFRP) cover. Ellipsoidal dome-shaped Al liners containing through cracks, which were made by pressure cycle tests, in the CFRP covers with total thickness of 6 mm (CFPR 3 mm, and Al 3 mm) were inspected by the system. While inducing eddy currents in the vessels with excitation fields at 100 Hz or 7 kHz, the vessels were rotated under the HTS-SQUID. Above the cracks, anomalous signals due to the cracks were clearly detected at both frequencies. These results suggested the SQUID-NDI technique would be a possible candidate for inspection of high-pressure multi-layer composite-Al vessels

  10. Non-destructive inspection using HTS-SQUID on aluminum liner covered by CFRP

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukade, Y. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)], E-mail: hatukade@eco.tut.ac.jp; Yotsugi, K. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Sakaguchi, Y. [SAMTECH Corporation, 1000-18 Enmyo-cho, Kashiwara City, Osaka 582-0027 (Japan); Tanaka, S. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2007-10-01

    An eddy-current-based SQUID non-destructive inspection (NDI) system to detect deep-lying cracks in multi-layer composite-Al vessels was developed taking advantage of the uncontested sensitivity of HTS-SQUID in low-frequency range. An HTS-SQUID gradiometer was mounted in a pulse tube cryocooler. A pair of differential coils with C-shaped ferrite cores was employed to induce an enhanced eddy current in an Al vessel wrapped in a carbon fiber reinforced plastic (CFRP) cover. Ellipsoidal dome-shaped Al liners containing through cracks, which were made by pressure cycle tests, in the CFRP covers with total thickness of 6 mm (CFPR 3 mm, and Al 3 mm) were inspected by the system. While inducing eddy currents in the vessels with excitation fields at 100 Hz or 7 kHz, the vessels were rotated under the HTS-SQUID. Above the cracks, anomalous signals due to the cracks were clearly detected at both frequencies. These results suggested the SQUID-NDI technique would be a possible candidate for inspection of high-pressure multi-layer composite-Al vessels.

  11. An Ecological Perspective on Inshore Fisheries in the Main Hawaiian Islands

    OpenAIRE

    Smith, M. Kimberly

    1993-01-01

    A description of fisheries within a depth of 100 fathoms is provided for the eight southeastern-most islands of the Hawaiian Archipelago, known as the main Hawaiian Islands (MHI). These are the inhabited islands of the State of Hawaii and are those most subject to inshore fishing pressure, because of their accessibility. Between 1980 and 1990, an average of 1,300 short tons of fishes and invertebrates were reported annually within 100 fm by commercial fishermen. Total landings may be signific...

  12. jSquid: a Java applet for graphical on-line network exploration.

    Science.gov (United States)

    Klammer, Martin; Roopra, Sanjit; Sonnhammer, Erik L L

    2008-06-15

    jSquid is a graph visualization tool for exploring graphs from protein-protein interaction or functional coupling networks. The tool was designed for the FunCoup web site, but can be used for any similar network exploring purpose. The program offers various visualization and graph manipulation techniques to increase the utility for the user. jSquid is available for direct usage and download at http://jSquid.sbc.su.se including source code under the GPLv3 license, and input examples. It requires Java version 5 or higher to run properly. erik.sonnhammer@sbc.su.se Supplementary data are available at Bioinformatics online.

  13. Properties of high temperature SQUIDS

    International Nuclear Information System (INIS)

    Falco, C.M.; Wu, C.T.

    1978-01-01

    A review is given of the present status of weak links and dc and rf biased SQUIDs made with high temperature superconductors. A method for producing reliable, reproducible devices using Nb 3 Sn is outlined, and comments are made on directions future work should take

  14. Macroscopic quantum tunneling in a dc SQUID

    International Nuclear Information System (INIS)

    Chen, Y.C.

    1986-01-01

    The theory of macroscopic quantum tunneling is applied to a current-biased dc SQUID whose dynamics can be described by a two-dimensional mechanical system with a dissipative environment. Based on the phenomenological model proposed by Caldeira and Leggett, the dissipative environment is represented by a set of harmonic oscillators coupling to the system. After integrating out the environmental degrees of freedom, an effective Euclidean action is found for the two-dimensional system. The action is used to provide the quantum tunneling rate formalism for the dc SQUID. Under certain conditions, the tunneling rate reduces to that of a single current-biased Josephson junction with an adjustable effective critical current

  15. Development and testing of high temperature-vector-SQUID conductor-magnetometers for the electro-magnetic exploration of our deposits. Final report; SQUID-Anwendungen - Entwicklung und Erprobung von Hochtemperatur-Vektor-Supraleiter SQUID-Magnetometern fuer die elektromagnetische Exploration von Lagerstaetten. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Matzander, U.; Friedrichs, B.

    2000-03-01

    Aim of the was the development of a prototype of a 3 axis HTc SQUID magnetometer for the geophysical exploration. The prototype was tested during the project in Germany and in China. Metronix task was the supervision of the development with the direction that the sensor can be used for field measurements and that the manufacturing costs will be acceptable. For magnetotelluric measurements (MT/CSAMT) further development is required to enhance the drift and noise properties of the sensor. The advantages in the geophysical TEM exploration are: greater sounding depth and good conductors (ore bodies) can be penetrated completely; the thickness of the resource can be estimated this way. At the same time the measuring time can be reduced tremendously because of the better signal to noise ratio. The productivity of the measuring campaign increases. If due to further developments coils systems can be replaced in total by the SQUID, SQUID systems will dominate the TEM market. (orig.) [German] Ziel des Projektes war es, einen Prototyp eines 3-achsigen HTc SQUIDS zur Verfuegung zu haben, welcher die Anforderungen fuer geophysikalische Messungen erfuellt. Dieser Prototyp wurde im Laufe des Projektes in Deutschland und China getestet. Die Rolle der Firma Metronix in diesem Projekt war die Einflussnahme auf die Entwicklung in der Form, dass zum einen die aus der Feldmesstechnik resultierenden Anforderungen beruecksichtigt werden, zum anderen auf eine spaetere kostenguenstige Herstellung geachtet wird. Bei magnetotellurischen Messungen (MT/CSAMT) besteht weiterer Bedarf an Verbesserungen hinsichtlich der Drift- und Rauscheigenschaften des Sensors. Fuer die geophysikalische Exploration in der TEM ergeben sich folgende Vorteile: die Erkundungstiefe ist groesser und gute Leiter (Erzkoerper) koennen vollstaendig durchteuft werden; damit kann die Maechtigkeit des Vorkommens bestimmt werden. Gleichzeitig kann auf Grund des besseren Signal / Rauschverhaeltnisses die Messzeit deutlich

  16. Nondestructive evaluation of metallic structures using a SQUID magnetometer

    International Nuclear Information System (INIS)

    Weinstock, H.; Nisenoff, M.

    1985-01-01

    We present one of the first reports of the use of SQUID instrumentation for nondestructive evaluation of electrically conducting and ferromagnetic specimens. We report preliminary experiments on the use of SQUIDs for the detection of defects (such as cracks, holes, weld seams, variations in wall thickness, effects of corrosion, etc.) in the walls of a hollow pipe, and for monitoring the magnetic state of a ferromagnetic sample under stress-strain loading conditions. (orig./BUD)

  17. Mobile HTS-SQUID NDE system with robot arm and active shielding using fluxgate

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukade, Y. [Department of Ecological Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)], E-mail: hatukade@eco.tut.ac.jp; Yotsugi, K.; Tanaka, S. [Department of Ecological Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2008-09-15

    A robot-arm-based mobile HTS-SQUID NDE system was developed for inspection of advanced structures such as hydrogen fuel cell tanks. In order to realize stable operation of HTS-SQUID exposed in Earth's field and robot arm's noise without flux trapping, flux jumping and unlocking during motion, a new active magnetic shielding (AMS) technique using fluxgate was introduced. The high sensitive fluxgate, which could measure magnetic field of up to several 10 {mu}T, was mounted near an HTS-SQUID gradiometer on the robot arm to measure the ambient noise and feed back its output to a compensation coil, which surrounded both SQUID and fluxgate to cancel the ambient noise around them. The AMS technique successfully enabled the HTS-SQUID gradiometer to be moved at 10 mm/s by the robot arm in unshielded environment without flux trapping, jumping and unlocking. Detection of hidden slots in multi-layer composite-metal structures imitating the fuel cell tank was demonstrated.

  18. Squids: applications outside the laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Falco, C M

    1978-07-01

    Originally thought to be rather esoteric, SQUIDS (superconducting quantum interference devices) have moved from the realms of theory to practical application since 1962. The promise for the not-too-distant future is a superconducting computer, with 10/sup 5/ logic elements in a 1cm cube.

  19. Improved Algorithms for Accurate Retrieval of UV - Visible Diffuse Attenuation Coefficients in Optically Complex, Inshore Waters

    Science.gov (United States)

    Cao, Fang; Fichot, Cedric G.; Hooker, Stanford B.; Miller, William L.

    2014-01-01

    Photochemical processes driven by high-energy ultraviolet radiation (UVR) in inshore, estuarine, and coastal waters play an important role in global bio geochemical cycles and biological systems. A key to modeling photochemical processes in these optically complex waters is an accurate description of the vertical distribution of UVR in the water column which can be obtained using the diffuse attenuation coefficients of down welling irradiance (Kd()). The Sea UV Sea UVc algorithms (Fichot et al., 2008) can accurately retrieve Kd ( 320, 340, 380,412, 443 and 490 nm) in oceanic and coastal waters using multispectral remote sensing reflectances (Rrs(), Sea WiFS bands). However, SeaUVSeaUVc algorithms are currently not optimized for use in optically complex, inshore waters, where they tend to severely underestimate Kd(). Here, a new training data set of optical properties collected in optically complex, inshore waters was used to re-parameterize the published SeaUVSeaUVc algorithms, resulting in improved Kd() retrievals for turbid, estuarine waters. Although the updated SeaUVSeaUVc algorithms perform best in optically complex waters, the published SeaUVSeaUVc models still perform well in most coastal and oceanic waters. Therefore, we propose a composite set of SeaUVSeaUVc algorithms, optimized for Kd() retrieval in almost all marine systems, ranging from oceanic to inshore waters. The composite algorithm set can retrieve Kd from ocean color with good accuracy across this wide range of water types (e.g., within 13 mean relative error for Kd(340)). A validation step using three independent, in situ data sets indicates that the composite SeaUVSeaUVc can generate accurate Kd values from 320 490 nm using satellite imagery on a global scale. Taking advantage of the inherent benefits of our statistical methods, we pooled the validation data with the training set, obtaining an optimized composite model for estimating Kd() in UV wavelengths for almost all marine waters. This

  20. Second order gradiometer and dc SQUID integrated on a planar substrate

    Science.gov (United States)

    van Nieuwenhuyzen, G. J.; de Waal, V. J.

    1985-02-01

    An integrated system of a thin-film niobium dc superconducting quantum interference device (SQUID) and a second order gradiometer on a planar substrate is described. The system consists of a dc SQUID with eight loops in parallel, each sensitive to the second derivative ∂2Bz/∂x2 of the magnetic field. The calculated SQUID inductance is 1.3 nH. With an overall size of 16×16.5 mm2 a sensitivity of 1.5×10-9 Tm-2 Hz-1/2 is obtained. The measured transfer function for uniform fields perpendicular to the plane of the gradiometer is 2.1×10-7 T Φ-10.

  1. Prospects on the application of HTS SQUID magnetometry to nondestructive evaluation (NDE)

    Science.gov (United States)

    Weinstock, H.

    1993-04-01

    In light of recent advances in the fabrication of low-noise HTS SQUIDs, a review is presented on the use of LTS SQUID magnetometry for nondestructive evaluation (NDE). Examples are given on applications relating to defects in steel, subsurface cracks in aircraft frames, and voids in non-metallic structures. HTS SQUIDs may make a significant difference in the acceptance of these applications because sensing coils will be closer to a sample under test, there will be greater instrument portability and the problem of bringing liquid helium to remote locations will be eliminated.

  2. Compact integrated dc SQUID gradiometer

    Science.gov (United States)

    de Waal, V. J.; Klapwijk, T. M.

    1982-10-01

    An all-niobium integrated system of first-order gradiometer and dc suprconducting quantum interference device (SQUID) has been developed. It is relatively simple to fabricate, has an overall size of 17×12 mm and a sensitivity of 3.5×10-12 T m-1 Hz-1/2.

  3. Technology for SQUID systems for the application in magnetically disturbed environment. Final report

    International Nuclear Information System (INIS)

    Schultze, V.; Fritzsch, L.; Thrum, F.; Stolz, R.; Chwala, A.

    1996-06-01

    International available SQUID systems, as used for example in biomagnetic research, obtain high sensitivities for magnetic fields or magnetic fieldgradients. However, these systems were optimised for operation in magnetically shielded rooms. Goal of this project was to develop SQUIDs suppressing the external noise and therefore are able to operate without external shielding in normal environments. As a consequence, the required Nb/AlO x /Nb technology has also been developed. The resulting planar SQUID gradiometers as produced at the IPHT, reached a suppression of homogeneous fields up to 5 x 10 4 for a magnetic field sensitivity c , project. SQUID gradiometers, produced using YBCO technology, were successfully operated in non shielded eddy current NDE measurements in the lab. (orig.) [de

  4. New version of toroidal SQUID sensor

    International Nuclear Information System (INIS)

    Zarembinski, S.; Kachniarz, J.

    1983-01-01

    A report is given on the design and fabrication of a mechanically stable and thermal shock resistant SQUID sensor. The sensor is vacuum sealed while the access to the adjustment of its point contact is left open

  5. Identifying Pelagic Habitat Hotspots of Neon Flying Squid in the Temperate Waters of the Central North Pacific.

    Science.gov (United States)

    Alabia, Irene D; Saitoh, Sei-Ichi; Mugo, Robinson; Igarashi, Hiromichi; Ishikawa, Yoichi; Usui, Norihisa; Kamachi, Masafumi; Awaji, Toshiyuki; Seito, Masaki

    2015-01-01

    We identified the pelagic habitat hotspots of the neon flying squid (Ommastrephes bartramii) in the central North Pacific from May to July and characterized the spatial patterns of squid aggregations in relation to oceanographic features such as mesoscale oceanic eddies and the Transition Zone Chlorophyll-a Front (TZCF). The data used for the habitat model construction and analyses were squid fishery information, remotely-sensed and numerical model-derived environmental data from May to July 1999-2010. Squid habitat hotspots were deduced from the monthly Maximum Entropy (MaxEnt) models and were identified as regions of persistent high suitable habitat across the 12-year period. The distribution of predicted squid habitat hotspots in central North Pacific revealed interesting spatial and temporal patterns likely linked with the presence and dynamics of oceanographic features in squid's putative foraging grounds from late spring to summer. From May to June, the inferred patches of squid habitat hotspots developed within the Kuroshio-Oyashio transition zone (KOTZ; 37-40°N) and further expanded north towards the subarctic frontal zone (SAFZ; 40-44°N) in July. The squid habitat hotspots within the KOTZ and areas west of the dateline (160°W-180°) were likely influenced and associated with the highly dynamic and transient oceanic eddies and could possibly account for lower squid suitable habitat persistence obtained from these regions. However, predicted squid habitat hotspots located in regions east of the dateline (180°-160°W) from June to July, showed predominantly higher squid habitat persistence presumably due to their proximity to the mean position of the seasonally-shifting TZCF and consequent utilization of the highly productive waters of the SAFZ.

  6. Compact integrated dc SQUID gradiometer

    Energy Technology Data Exchange (ETDEWEB)

    de Waal, V.J.; Klapwijk, T.M.

    1982-10-01

    An all-niobium integrated system of first-order gradiometer and dc suprconducting quantum interference device (SQUID) has been developed. It is relatively simple to fabricate, has an overall size of 17 x 12 mm and a sensitivity of 3.5 x 10/sup -12/ T m/sup -1/ Hz/sup -1/2/.

  7. High-T /SUB c/ Superconducting integrated circuit: a dc SQUID with input coil

    International Nuclear Information System (INIS)

    Di Iorio, M.S.; Beasley, M.R.

    1985-01-01

    We have fabricated a high transition temperature superconducting integrated circuit consisting of a dc SQUID and an input coupling coil. The purpose is to ascertain the generic problems associated with constructing a high-T /SUB c/ circuit as well as to fabricate a high performance dc SQUID. The superconductor used for both the SQUID and the input coil is Nb 3 Sn which must be deposited at 800 0 C. Importantly, the insulator separating SQUID and input coil maintains its integrity at this elevated temperature. A hole in the insulator permits contact to the innermost winding of the coil. This contact has been achieved without significant degradation of the superconductivity. Consequently, the device operates over a wide temperature range, from below 4.2 K to near T /SUB c/

  8. Cryostats for SQUID magnetometers

    International Nuclear Information System (INIS)

    Testard, O.A.; Locatelli, M.

    1982-05-01

    A non metallic and non magnetic cryostat, with a very low thermal budget and a container type autonomy was developed, to condition S.Q.U.I.D. magnetometers which maximum sensitivity reaches 10 -14 Tesla Hertzsup(-1/2). This instrumentation puts in hand new concepts of composite materials, thermal shock and vibration resistant, multilayer thermal radiative insulation also to the prouve of vibrations with thermal equivalent emissivity lower than 10 -3

  9. Analysis of the ac SQUID with low inductance and low critical current

    DEFF Research Database (Denmark)

    Sørensen, O. H.

    1976-01-01

    The properties of the ac SQUID magnetometer has been analyzed. The results are valid in the low-inductance low-critical-current regime, where the Lri0 producted is belowthe value at which the relation between the enclosed and externally applied magnetic dc flux becomes reentrant. The effects...... of the screening current circulating in the SQUID ring as well as of the SQUID-ring time constant, tau-Lr/R9 are taken into account. Here LR IS THE SQUID-ring inductance, and R is the shunt resistance in the shunted junction model assumed to describe the weak link. It is shown that for finite values of omegatau...... constriuctively with the result that the optimal response occurs at a definite and finite value of omegatau. If omegatau is increased beyond this optimal value the weak link behavior is dominated by the Ohmic current channel implying that only if the shunt conductance contains a term depending...

  10. Flicker (1/f) noise in tunnel junction DC SQUIDS

    International Nuclear Information System (INIS)

    Koch, R.H.; Clarke, J.; Goubau, W.M.; Martinis, J.M.; Pegrum, C.M.; Van Harlingen, D.J.

    1983-01-01

    We have measured the spectral density of the 1/f voltage noise in current-biased resistively shunted Josephson tunnel junctions and dc SQUIDs. A theory in which fluctuations in the temperature give rise to fluctuations in the critical current and hence in the voltage predicts the magnitude of the noise quite accurately for junctions with areas of about 2 x 10 4 μm 2 , but significantly overestimates the noise for junctions with areas of about 6 μm 2 . DC SQUIDs fabricated from these two types of junctions exhibit substantially more 1/f voltage noise than would be predicted from a model in which the noise arises from critical current fluctuations in the junctions. This result was confirmed by an experiment involving two different bias current and flux modulation schemes, which demonstrated that the predominant 1/f voltage noise arises not from critical current fluctuations, but from some unknown source that can be regarded as an apparent 1/f flux noise. Measurements on five different configurations of dc SQUIDs fabricated with thin-film tunnel junctions and with widely varying areas, inductances, and junction capacitances show that the spectral density of the 1/f equivalent flux noise is roughtly constant, within a factor of three of (10 -10 /f)phi 2 0 Hz -1 . It is emphasized that 1/f flux noise may not be the predominant source of 1/f noise in SQUIDS fabricated with other technologies

  11. SQUID sensor application for small metallic particle detection

    International Nuclear Information System (INIS)

    Tanaka, Saburo; Hatsukade, Yoshimi; Ohtani, Takeyoshi; Suzuki, Shuichi

    2009-01-01

    High-Tc superconducting quantum interference device (SQUID) is an ultra-sensitive magnetic sensor. Since the performance of the SQUID is improved and stabilized, now it is ready for application. One strong candidate for application is a detection system of magnetic foreign matters in industrial products or beverages. There is a possibility that ultra-small metallic foreign matter has been accidentally mixed with industrial products such as lithium ion batteries. If this happens, the manufacturer of the product suffers a great loss recalling products. The outer dimension of metallic particles less than 100 μm cannot be detected by an X-ray imaging, which is commonly used for the inspection. Ionization of the material is also a big issue for beverages in the case of the X-ray imaging. Therefore a highly sensitive and safety detection system for small foreign matters is required. We developed detection systems based on high-Tc SQUID with a high-performance magnetic shield. We could successfully measure small iron particles of 100 μm on a belt conveyer and stainless steel balls of 300 μm in water. These detection levels were hard to be achieved by a conventional X-ray detection or other methods

  12. Thermoelectric SQUID method for the detection of segregations

    Science.gov (United States)

    Hinken, Johann H.; Tavrin, Yury

    2000-05-01

    Aero engine turbine discs are most critical parts. Material inhomogeneities can cause disc fractures during the flight with fatal air disasters. Nondestructive testing (NDT) of the discs in various machining steps is necessary and performed as well as possible. Conventional NDT methods, however, like eddy current testing and ultrasonic testing have unacceptable limits. For example, subsurface segregations often cannot be detected directly but only indirectly in such cases when cracks already have developed from them. This may be too late. A new NDT method, which we call the Thermoelectric SQUID Method, has been developed. It allows for the detection of metallic inclusions within non-ferromagnetic metallic base material. This paper describes the results of a feasibility study on aero engine turbine discs made from Inconel® 718. These contained segregations that had been detected before by anodic etching. With the Thermoelectric SQUID Method, these segregations were detected again, and further segregations below the surfaces have been found, which had not been detected before. For this new NDT method the disc material is quasi-transparent. The Thermoelectric SQUID Method is also useful to detect distributed and localized inhomogeneities in pure metals like niobium sheets for particle accelerators.

  13. The abundance of herbivorous fish on an inshore Red Sea reef following a mass coral bleaching event

    KAUST Repository

    Khalil, Maha T.; Cochran, Jesse; Berumen, Michael L.

    2013-01-01

    and scarine labrids) were comparatively studied for an inshore reef that was severely impacted by a mass coral bleaching event in 2010 and an unaffected reef within the same region. Densities were found to be significantly higher on the affected reef, most

  14. [Effects of Long-term Implementation of the Flow-Sediment Regulation Scheme on Grain and Clay Compositions of Inshore Sediments in the Yellow River Estuary].

    Science.gov (United States)

    Wang, Miao-miao; Sun, Zhi-gao; Lu, Xiao-ning; Wang, Wei; Wang, Chuan-yuan

    2015-04-01

    Based on the laser particle size and X-ray diffraction (XRD) analysis, 28 sediment samples collected from the inshore region of the Yellow River estuary in October 2013 were determined to discuss the influence of long-term implementation of the flow-sediment regulation scheme (FSRS, initiated in 2002) on the distributions of grain size and clay components (smectite, illite, kaolinite and chlorite) in sediments. Results showed that, after the FSRS was implemented for more than 10 years, although the proportion of sand in inshore sediments of the Yellow River estuary was higher (average value, 23.5%) than those in sediments of the Bohai Sea and the Yellow River, silt was predominated (average value, 59.1%) and clay components were relatively low (average value, 17.4%). The clay components in sediments of the inshore region in the Yellow River estuary were close with those in the Yellow River. The situation was greatly changed due to the implementation of FSRS since 2002, and the clay components were in the order of illite > smectite > chlorite > kaolinite. This study also indicated that, compared to large-scale investigation in Bohai Sea, the local study on the inshore region of the Yellow River estuary was more favorable for revealing the effects of long-term implementation of the FSRS on sedimentation environment of the Yellow River estuary.

  15. Application of squids in the Iwate create project

    International Nuclear Information System (INIS)

    Yoshizawa, M.; He, D.F.; Nakai, K.; Kobayashi, K.; Nakamura, Y.; Yaegashi, M.; Ito, M.; Yashiro, H.; Daibo, M.; Simizu, T.; Uchikawa, Y.; Noto, K.

    2005-01-01

    We have developed a 64-channel magnetocardiograph (MCG) system for the diagnosis of heart disease. The MCG is characterized by its display of a unique three-dimensional image of bio-currents flowing inside the human body. The outline of the heart can be displayed without use of MRI. A mobile SQUID-based non-distractive evaluation apparatus was realized by the active shielding technique. The system can offer information from beneath the surface of the specimen by using a saw-wave excitation method. This mobile technology enables us to inspect ferromagnetic materials, whose high magnetic field rules out the use of a conventional SQUID apparatus near them

  16. Scanning high-Tc SQUID imaging system for magnetocardiography

    International Nuclear Information System (INIS)

    Yang, H-C; Wu, T-Y; Horng, H-E; Wu, C-C; Yang, S Y; Liao, S-H; Wu, C-H; Jeng, J T; Chen, J C; Chen, Kuen-Lin; Chen, M J

    2006-01-01

    A scanning magnetocardiography (MCG) system constructed from SQUID sensors offers potential to basic or clinical research in biomagnetism. In this work, we study a first order scanning electronic high-T c (HTS) SQUID MCG system for biomagnetic signals. The scanning MCG system was equipped with an x-y translation bed powered by step motors. Using noise cancellation and μ-metal shielding, we reduced the noise level substantially. The established scanning HTS MCG system was used to study the magnetophysiology of hypercholesterolaemic (HC) rabbits. The MCG data of HC rabbits were analysed. The MCG contour map of HC rabbits provides experimental models for the interpretation of human cardiac patterns

  17. Second order gradiometer and dc SQUID integrated on a planar substrate

    Energy Technology Data Exchange (ETDEWEB)

    van Nieuwenhuyzen, G.J.; de Waal, V.J.

    1985-02-15

    An integrated system of a thin-film niobium dc superconducting quantum interference device (SQUID) and a second order gradiometer on a planar substrate is described. The system consists of a dc SQUID with eight loops in parallel, each sensitive to the second derivative partial/sup 2/B/sub z//partialx/sup 2/ of the magnetic field. The calculated SQUID inductance is 1.3 nH. With an overall size of 16 x 16.5 mm/sup 2/ a sensitivity of 1.5 x 10/sup -9/ Tm/sup -2/ Hz/sup -1//sup ///sup 2/ is obtained. The measured transfer function for uniform fields perpendicular to the plane of the gradiometer is 2.1 x 10/sup -7/ T Phi/sup -1//sub 0/.

  18. Cross-shelf transport of sub-thermocline nitrate by the internal tide and rapid (3-6 h) incorporation by an inshore macroalga

    Science.gov (United States)

    Ladah, Lydia B.; Filonov, Anatoliy; Lavín, Miguel F.; Leichter, James J.; Zertuche-González, José A.; Pérez-Mayorga, Diana M.

    2012-07-01

    During summer in shallow waters off Baja California, Mexico, the internal tide is a dominant thermal feature of the water column. However, its importance for sub-thermocline nutrient provision to benthic macroalgae is unknown. In order to determine if internal motions provide nutrients to macroalgae in summer, Ulva lactuca was outplanted at inshore stations for short (3 and 6 h) intervals, at the surface, 5 and 10 m depth, and tissue nitrogen content was measured before and after each deployment. Concurrently temperature, currents, and nutrients were measured using moored thermistors, current profilers, CTDs, Niskin bottles, and an in-situ UV absorbance nitrate sensor (ISUS). Discrete pulses of cool, nutrient-rich water were horizontally displaced at least 4 km on the shelf and shoaled more than 20 m depth at the semidiurnal frequency, resulting in more than a 10-fold change in the concentration of nitrate. Inshore, tissue nitrogen of Ulva outplants increased significantly during longer exposures to this cool water. At this site, the semidiurnal signal dominates water column temperature fluctuations from April to November, with summer showing the greatest cooling (up to 5 °C) in a one-hour period. We estimated that 11% of the days of a year show internal waves that would cause a significant change in nutrient availability to macroalgae at 5 m depth. This study supports the hypothesis that nitrate can reach and be rapidly incorporated by inshore macroalgae such as Ulva through transport forced by the internal tide, and that even very short (internal tide provides a significant, yet understudied, high frequency nutrient source to inshore primary producers, particularly in summer.

  19. Dipole location using SQUID based measurements: Application to magnetocardiography

    Science.gov (United States)

    Mariyappa, N.; Parasakthi, C.; Sengottuvel, S.; Gireesan, K.; Patel, Rajesh; Janawadkar, M. P.; Sundar, C. S.; Radhakrishnan, T. S.

    2012-07-01

    We report a method of inferring the dipole location using iterative nonlinear least square optimization based on Levenberg-Marquardt algorithm, wherein, we use different sets of pseudo-random numbers as initial parameter values. The method has been applied to (i) the simulated data representing the calculated magnetic field distribution produced by a point dipole placed at a known position, (ii) the experimental data from SQUID based measurements of the magnetic field distribution produced by a source coil carrying current, and (iii) the actual experimentally measured magnetocardiograms of human subjects using a SQUID based system.

  20. Cephalopods and cetaceans as indicators of offshore bioavailability of cadmium off Central South Brazil Bight

    Energy Technology Data Exchange (ETDEWEB)

    Dorneles, Paulo Renato [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil) and Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: dorneles@biof.ufrj.br; Lailson-Brito, Jose [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil) and Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: lailson@uerj.br; Aguiar dos Santos, Roberta [Centro de Pesquisa e Gestao de Recursos Pesqueiros do Litoral Sudeste e Sul, IBAMA, 88301-700 Itajai, SC (Brazil)]. E-mail: gibteuthis@yahoo.com.br; Silva da Costa, Paulo Alberto [Laboratorio de Dinamica de Populacoes Marinhas, UNIRIO, 22290-240 Rio de Janeiro, RJ (Brazil)]. E-mail: pauloascosta@uol.com.br; Malm, Olaf [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil)]. E-mail: olaf@biof.ufrj.br; Azevedo, Alexandre Freitas [Laboratorio de Mamiferos Aquaticos, Dept. Oceanografia, UERJ, 20550-013 Rio de Janeiro, RJ (Brazil)]. E-mail: azevedo.alex@uol.com.br; Machado Torres, Joao Paulo [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-900 Rio de Janeiro, RJ (Brazil)]. E-mail: jptorres@biof.ufrj.br

    2007-07-15

    Regarding Brazilian coast, industrial and urban developments are concentrated along Central South Brazil Bight. Samples from inshore and offshore species from the concerned area were analyzed, comprising 24 cetaceans (9 species) and 32 squids (2 species). Cadmium was determined by GFAAS and our results were in agreement with certified values (DOLT-2, NRCC). Mean cadmium concentration (in {mu}g/g, wet weight) observed in the digestive gland of sexually mature Argentine short-finned squids (Illex argentinus) was 1002.9. To our knowledge this is the highest cadmium level ever reported for a cephalopod. Concerning cetaceans, our results include one of the highest renal cadmium concentrations described for striped dolphins (71.29 {mu}g/g, wet weight). Anthropogenic action, upwelling and cannibalism of Argentine short-finned squid on the studied area are possible reasons for such remarkable cadmium concentrations. - Cd levels in ommastrephid squids from Brazil are the highest ever reported for cephalopods.

  1. Cephalopods and cetaceans as indicators of offshore bioavailability of cadmium off Central South Brazil Bight

    International Nuclear Information System (INIS)

    Dorneles, Paulo Renato; Lailson-Brito, Jose; Aguiar dos Santos, Roberta; Silva da Costa, Paulo Alberto; Malm, Olaf; Azevedo, Alexandre Freitas; Machado Torres, Joao Paulo

    2007-01-01

    Regarding Brazilian coast, industrial and urban developments are concentrated along Central South Brazil Bight. Samples from inshore and offshore species from the concerned area were analyzed, comprising 24 cetaceans (9 species) and 32 squids (2 species). Cadmium was determined by GFAAS and our results were in agreement with certified values (DOLT-2, NRCC). Mean cadmium concentration (in μg/g, wet weight) observed in the digestive gland of sexually mature Argentine short-finned squids (Illex argentinus) was 1002.9. To our knowledge this is the highest cadmium level ever reported for a cephalopod. Concerning cetaceans, our results include one of the highest renal cadmium concentrations described for striped dolphins (71.29 μg/g, wet weight). Anthropogenic action, upwelling and cannibalism of Argentine short-finned squid on the studied area are possible reasons for such remarkable cadmium concentrations. - Cd levels in ommastrephid squids from Brazil are the highest ever reported for cephalopods

  2. SQUID magnetometer using sensitivity correction signal for non-magnetic metal contaminants detection

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Toshifumi, E-mail: sakuta.k@usp.ac.jp; Ohashi, Masaharu; Sakuta, Ken

    2016-11-15

    Highlights: • A high-frequency excitation is necessary to detect nonmagnetic metals using SQUID. • It is possible to detect a high-frequency magnetic field using the open loop technique. • Open loop operation leads to a change in the conversion factor. • Conversion between voltage and magnetic field for open loop operation are examined. - Abstract: Measurement methods with SQUID can accurately detect small magnetic metal contaminants based on their magnetic remanence. But, a high-frequency excitation is necessary to detect nonmagnetic metals, on the base of contrasts in electric conductivity. In this work, an open loop technique is introduced to facilitate this. The SQUID is negative feedback controlled (flux locked loop (FLL) operation) for the low frequency range, which includes significant noise due to the movement of the magnetic body or the change of the ambient magnetic field composed of the geomagnetic field and technical signals, and it operates in an open loop configuration for the high frequency range. When using the open loop technique, negative feedback is not applied to the high frequency range. Consequently, the V–Φ characteristic changes due to various causes, which leads to variations in the conversion factor between the SQUID output voltage and the magnetic field. In this study, conversion techniques for the magnetic field for open loop operation of SQUID in the high frequency range are examined.

  3. SQUID magnetometer using sensitivity correction signal for non-magnetic metal contaminants detection

    International Nuclear Information System (INIS)

    Yagi, Toshifumi; Ohashi, Masaharu; Sakuta, Ken

    2016-01-01

    Highlights: • A high-frequency excitation is necessary to detect nonmagnetic metals using SQUID. • It is possible to detect a high-frequency magnetic field using the open loop technique. • Open loop operation leads to a change in the conversion factor. • Conversion between voltage and magnetic field for open loop operation are examined. - Abstract: Measurement methods with SQUID can accurately detect small magnetic metal contaminants based on their magnetic remanence. But, a high-frequency excitation is necessary to detect nonmagnetic metals, on the base of contrasts in electric conductivity. In this work, an open loop technique is introduced to facilitate this. The SQUID is negative feedback controlled (flux locked loop (FLL) operation) for the low frequency range, which includes significant noise due to the movement of the magnetic body or the change of the ambient magnetic field composed of the geomagnetic field and technical signals, and it operates in an open loop configuration for the high frequency range. When using the open loop technique, negative feedback is not applied to the high frequency range. Consequently, the V–Φ characteristic changes due to various causes, which leads to variations in the conversion factor between the SQUID output voltage and the magnetic field. In this study, conversion techniques for the magnetic field for open loop operation of SQUID in the high frequency range are examined.

  4. Characterization of thermal aging of duplex stainless steel by SQUID

    International Nuclear Information System (INIS)

    Isobe, Y.; Kamimura, A.; Aoki, K.; Nakayasu, F.

    1995-01-01

    Thermal aging is a growing concern for long-term-aged duplex stainless steel piping in nuclear power plants. Superconducting QUantum Interference Device (SQUID) was used for the detection of thermal aging of SUS329 rolled duplex stainless steel and SCS16 cast duplex stainless steel. It was found that the SQUID output signal pattern in the presence of AC magnetic field applied to the specimen was sensitive to the changes in electromagnetic properties due to thermal aging

  5. Opportunistic acoustic recordings of (potential) orangeback flying squid Sthenoteuthis pteropus in the Central Eastern Atlantic

    Science.gov (United States)

    Peña, Marian; Villanueva, Roger; Escánez, Alejandro; Ariza, Alejandro

    2018-03-01

    Squids are fast swimmers that are difficult to catch by nets and to record with echosounders in the open ocean. A rare detection of orangeback flying squid Sthenoteuthis pteropus in the Central Eastern Atlantic Ocean off the coast of Senegal was accomplished during the MAFIA oceanographic survey carried out between Brazil and the Canary Islands in April 2015. Although net sampling did not yield any subadult or adult individuals, dozens were visually detected from the vessel jumping out of the water at night and displaying their characteristic dorsal photophore patch. A few squids were caught with fishing lines and identified at the species level. The acoustic echograms revealed distinctive previously unobserved acoustic echotraces that seemed to be caused by those squids, which were the only new species detected at that station (over a bottom depth ranging from 4010 to 5215 m, between 10° 45‧ N 22° 41‧ W and 10° 53‧ N 22° 40‧ W). The acoustic response and swimming behaviour shown by those echotraces reinforced this hypothesis. The (potentially) squid recordings dove rapidly (0.19 m/s to 0.48 m/s) from around 10 m below the mesopelagic fish layer, which had migrated to the subsurface at night (35 m depth), to depths of 70-95 m, and swam upward, apparently attacking fish from below. The morning squid migration to deeper waters (250-300 m) was also recorded acoustically. Downward movements of squid swimming at speeds of 0.22 m/s were calculated from the echogram, while the mesopelagic migrating fish swam at 0.27 m/s reaching 250 m depth. Sv120 - Sv38 averaged 2.7 ± 3.2 dB for the squid echotraces while the mesopelagic layer showed values of -8.8 ± 0.9 dB. These ranges agreed with values in the literature and from theoretical models. This study provides more insight into the migrating behaviour of oceanic squids, a species group that is poorly represented in the acoustic literature due to challenges in studying them.

  6. On-site detection of packaged squid freshness

    Science.gov (United States)

    Ahmad, Noor Azizah; Heng, Lee Yook; Salam, Faridah; Hanifah, Sharina Abu

    2018-04-01

    The development of indicator label for detection of total volatile basic nitrogen (TVB-N) is described. Dye extract from edible plants containing anthocyanins was immobilized onto iota-carrageenan as polymer matrix. TVB-N detection worked based on pH increase as the basic deterioration volatile amines generated in the package headspace. Results showed that the indicator label has changed color from blue to green after 12 hours of storage at ambient conditions. The TVB-N value was 38.9648 mg /100 g which is exceeded of acceptability level for seafood products. The pH value of squid flesh has also increased during storage. The colour values of L * and a * negative increases while b* negative decrease with increasing storage time. The indicator label is potentially used as freshness indicator for squid at ambient conditions.

  7. Squid Dissection: From Pen to Ink.

    Science.gov (United States)

    Brown, Cindy; Kisiel, Jim

    2003-01-01

    Introduces students to dissection, which is an important part of scientific discovery. Students not only gain an understanding of the anatomy of a squid, but also develop a sense of responsibility and respect for the animal that they are using as a learning tool. (Author/SOE)

  8. Reducing systematic errors in measurements made by a SQUID magnetometer

    International Nuclear Information System (INIS)

    Kiss, L.F.; Kaptás, D.; Balogh, J.

    2014-01-01

    A simple method is described which reduces those systematic errors of a superconducting quantum interference device (SQUID) magnetometer that arise from possible radial displacements of the sample in the second-order gradiometer superconducting pickup coil. By rotating the sample rod (and hence the sample) around its axis into a position where the best fit is obtained to the output voltage of the SQUID as the sample is moved through the pickup coil, the accuracy of measuring magnetic moments can be increased significantly. In the cases of an examined Co 1.9 Fe 1.1 Si Heusler alloy, pure iron and nickel samples, the accuracy could be increased over the value given in the specification of the device. The suggested method is only meaningful if the measurement uncertainty is dominated by systematic errors – radial displacement in particular – and not by instrumental or environmental noise. - Highlights: • A simple method is described which reduces systematic errors of a SQUID. • The errors arise from a radial displacement of the sample in the gradiometer coil. • The procedure is to rotate the sample rod (with the sample) around its axis. • The best fit to the SQUID voltage has to be attained moving the sample through the coil. • The accuracy of measuring magnetic moment can be increased significantly

  9. Non-destructive testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, D.F.; Fan, C.; Ruan, J.Z. [Midwest Superconductivity Inc., Lawrence, KS (United States)] [and others

    1994-12-31

    A SQUID is the most sensitive device to detect change in magnetic field. A non-destructive testing (NDT) device using high temperature SQUIDs and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUIDs. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology.

  10. Non-destructive testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    International Nuclear Information System (INIS)

    Lu, D.F.; Fan, C.; Ruan, J.Z.

    1994-01-01

    A SQUID is the most sensitive device to detect change in magnetic field. A non-destructive testing (NDT) device using high temperature SQUIDs and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUIDs. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology

  11. Development of Nb nanoSQUIDs based on SNS junctions for operation in high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Morosh, Viacheslav; Kieler, Oliver; Weimann, Thomas; Zorin, Alexander [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany); Mueller, Benedikt; Martinez-Perez, Maria Jose; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany)

    2016-07-01

    Investigation of the magnetization reversal of single magnetic nanoparticles requires SQUIDs with high spatial resolution, high spin sensitivity (a few Bohr magneton μ{sub B}) and at the same time sufficient stability in high magnetic fields. We fabricated dc nanoSQUIDs comprising overdamped SNS sandwich-type (Nb/HfTi/Nb) Josephson junctions using optimized technology based on combination of electron beam lithography and chemical-mechanical polishing. Our nanoSQUIDs have Josephson junctions with lateral dimensions ≤ 150 nm x 150 nm, effective loop areas < 0.05 μm{sup 2} and the distance between the Josephson junctions ≤ 100 nm. The feeding strip lines of the width ≤ 200 nm have been realized. The nanoSQUIDs have shown stable operation in external magnetic fields at least up to 250 mT. Sufficiently low level of flux noise resulting in spin sensitivity of few tens μ{sub B}/Hz{sup 1/2} has been demonstrated. A further reduction of the nanoSQUID size using our technology is possible.

  12. 33 CFR 334.1170 - San Pablo Bay, Calif.; gunnery range, Naval Inshore Operations Training Center, Mare Island...

    Science.gov (United States)

    2010-07-01

    ... range, Naval Inshore Operations Training Center, Mare Island, Vallejo. 334.1170 Section 334.1170... Operations Training Center, Mare Island, Vallejo. (a) The Danger Zone. A sector in San Pablo Bay delineated..., Vallejo, California, will conduct gunnery practice in the area during the period April 1 through September...

  13. How the SQUID was born

    International Nuclear Information System (INIS)

    Silver, Arnold H

    2006-01-01

    I was asked to speak about the discovery and invention of the SQUID at the International Superconducting Electronics Conference (ISEC) 2005 banquet. This narrative is based on my personal recollections of the sequence of events and the motivations. I have edited the text and added figures for clarity. Although it is an old story, it may contain some useful lessons

  14. How the SQUID was born

    Energy Technology Data Exchange (ETDEWEB)

    Silver, Arnold H [Northrop Grumman Space Technology, One Space Park, Redondo Beach, CA 90278 (United States)

    2006-05-15

    I was asked to speak about the discovery and invention of the SQUID at the International Superconducting Electronics Conference (ISEC) 2005 banquet. This narrative is based on my personal recollections of the sequence of events and the motivations. I have edited the text and added figures for clarity. Although it is an old story, it may contain some useful lessons.

  15. Effects of Gamma Irradiation on Shelf-Life and Sensory Scores of Squid Sundae under Accelerated Storage Conditions

    International Nuclear Information System (INIS)

    Kim, H.J.; Kim, K.B.W.R.; Kim, D.H.; Sunwoo, C.; Jung, S.A.; Jeong, D.H.; Jung, H.Y.; Ahn, D.H.; Kim, J.H.; Lee, J.W.; Do, S.R.; Byun, M.W.

    2012-01-01

    This study was conducted to examine the effects of gamma irradiation on the shelf-life and sensory scores of squid Sundae under accelerated storage conditions. Squid Sundae was stored at 37°C for 35 days following gamma irradiation at doses of 0, 10, and 20 kGy. For total viable cell counts, control and gamma-irradiated (GI) (10 kGy) squid Sundae were already spoiled in 4 days, whereas GI (20 kGy) squid Sundae showed complete suppression of bacterial growth during storage. There were no significant changes in pH values compared to the control. The VBN and TBARS (thiobarbituric acid reactive substance) values of GI (20 kGy) squid Sundae were significantly lower than those of the control. In addition, the induction period of GI (20 kGy) squid Sundae as measured by a Rancimat showed a higher level compared to that of the control. In the sensory evaluation, there were no significant changes between the control and GI samples. These results suggest that a dose of 20 kGy is the optimum and effective dose for preservation of squid Sundae. (author)

  16. Imaging of current density distributions with a Nb weak-link scanning nano-SQUID microscope

    Science.gov (United States)

    Shibata, Yusuke; Nomura, Shintaro; Kashiwaya, Hiromi; Kashiwaya, Satoshi; Ishiguro, Ryosuke; Takayanagi, Hideaki

    2015-10-01

    Superconducting quantum interference devices (SQUIDs) are accepted as one of the highest magnetic field sensitive probes. There are increasing demands to image local magnetic fields to explore spin properties and current density distributions in a two-dimensional layer of semiconductors or superconductors. Nano-SQUIDs have recently attracting much interest for high spatial resolution measurements in nanometer-scale samples. Whereas weak-link Dayem Josephson junction nano-SQUIDs are suitable to miniaturization, hysteresis in current-voltage (I-V) characteristics that is often observed in Dayem Josephson junction is not desirable for a scanning microscope. Here we report on our development of a weak-link nano-SQUIDs scanning microscope with small hysteresis in I-V curve and on reconstructions of two-dimensional current density vector in two-dimensional electron gas from measured magnetic field.

  17. Frequency-domain multiplex with eight-input SQUID and readout electronics over 1MHz

    International Nuclear Information System (INIS)

    Masui, K.; Takei, Y.; Ikeda, H.; Kimura, S.; Mitsuda, K.; Yamasaki, N.Y.

    2006-01-01

    In a magnetic summation method, TES and SQUID driving circuits are isolated and thus small crosstalk and stray impedance are expected. Since a FLL circuit with a large bandwidth and a small noise level is required for a SQUID, we designed and produced an electronics to meet our design of multiplexing with an 8-input SQUID. The FLL circuit achieved an open loop-gain bandwidth product of 8MHz with 1m wire length, which is enough for a TES to be operated with a bias current of 70μA, and a noise level of 30pA/Hz

  18. Routine clinical heart examinations using SQUID magnetocardiography at University of Tsukuba Hospital

    Science.gov (United States)

    Inaba, T.; Nakazawa, Y.; Yoshida, K.; Kato, Y.; Hattori, A.; Kimura, T.; Hoshi, T.; Ishizu, T.; Seo, Y.; Sato, A.; Sekiguchi, Y.; Nogami, A.; Watanabe, S.; Horigome, H.; Kawakami, Y.; Aonuma, K.

    2017-11-01

    A 64-channel Nb-based DC-SQUID magnetocardiography (MCG) system was installed at the University of Tsukuba Hospital (UTH) in March 2007 after obtaining Japanese pharmaceutical approval and insurance reimbursement approval. In the period between 2008 and 2016, the total number of patients was 10 085. The heart diseases diagnosed in fetuses as well as adults are mainly atrial arrhythmia, abnormal repolarization, ventricular arrhythmia, and fetal arrhythmia. In most cases of insufficient diagnostic accuracy with electrocardiography, SQUID MCG precisely revealed these heart diseases as an abnormal electrical current distribution. Based on success in routine examinations, SQUID MCG is now an indispensable clinical instrument with diagnostic software tuned up during routine use at UTH.

  19. Low-frequency noise in high-(Tc) superconductor Josephson junctions, SQUIDs, and magnetometers

    Science.gov (United States)

    Miklich, A. H.

    1994-05-01

    Design and performance of high-T(sub c) dc superconducting quantum interference devices (SQUID's), junctions that comprise them, and magnetometers made from them are described, with attention to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUID's; this suggests a poorly connected interface at the grain boundary junction. SQUID's from bicrystal junctions have levels of critical current noise controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5 x 10(exp -30) J Hz(exp -1) at 1 Hz is reported. Magnetometers in which a (9 mm)(exp 2) pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz(exp -1/2) down to frequencies below 1 Hz, improving to 39 fT Hz(exp -1/2) at 1 Hz with the addition of a 50mm-diameter single-turn flux transformer. Poor coupling to pickup loop makes it difficult to satisfy competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz(exp -1/2) in the white noise region is reported with a (10 mm)(exp 2) pickup loop. However, additional 1/f noise from processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz(exp -1/2). High-T(sub c) SQUID's exhibit additional 1/f noise when cooled in a nonzero static magnetic field because of additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution of 9.2 pV Hz(exp -1/2) at 10 Hz (24 pV Hz(exp -1/2) at 1 Hz) is described.

  20. Low-Frequency Noise in High-T Superconductor Josephson Junctions, Squids, and Magnetometers.

    Science.gov (United States)

    Miklich, Andrew Hostetler

    The design and performance of high-T_ {rm c} dc superconducting quantum interference devices (SQUIDs), the junctions that comprise them, and magnetometers made from them are described, with special attention paid to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUIDs. This noise suggests a poorly connected interface at the grain boundary junction. SQUIDs from bicrystal junctions, in contrast, have levels of critical current noise that are controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5times 10^{-30} J Hz^ {-1} at 1 Hz is reported. Magnetometers in which a (9 mm)^2 pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz^{-1/2} down to frequencies below 1 Hz, improving to 39 fT Hz^{-1/2} at 1 Hz with the addition of a 50 mm-diameter single-turn flux transformer. Although the performance of these devices is sufficient for single -channel biomagnetometry or geophysical studies, their relatively poor coupling to the pickup loop makes it difficult to satisfy the competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz^{-1/2} in the white noise region is reported with a (10 mm) ^2 pickup loop. However, additional 1/f noise from the processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz^ {-1/2}. High-T_{ rm c} SQUIDs are shown to exhibit additional 1/f noise when they are cooled in a nonzero static magnetic field because of the additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05 mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution

  1. The bases for the development of high-temperature integrated squid-systems

    International Nuclear Information System (INIS)

    Polushkin, V.N.

    1992-01-01

    The current state of high-Tc superconducting thinfilm Josepson junctions and SQUIDs developing is reviewed. The prospects of application of new devices in supersensitive measurement apparatus are analyzed. It is shown that high T c SQUIDs are able seriously to influence further development of information and measurement engineering as on their base the series of microelectronic elements and devices of new generation can be built. 84 refs.; 16 figs.; 3 tabs

  2. SQUID-based noise thermometer for sub-Millikelvin refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Marco; Beyer, Joern; Klemm, Monique [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Alivaliollahi, Sassan; Barthelmess, Henry [Magnicon GmbH, Barkhausenweg 11, 22339 Hamburg (Germany)

    2015-07-01

    The magnetic field fluctuation thermometer (MFFT) is a high-accuracy SQUID-based noise thermometer suitable for sub-Kelvin thermometry. A highly sensitive low-Tc SQUID magnetometer detects inductively the magnetic field fluctuation above a metal surface. The fluctuations are generated by the thermal activated noise currents inside the metal body that is thermally anchored to the temperature stage to be measured. The spectral shape is independent of temperature as the electrical conductivity is constant and the geometry is fixed. The magnetic noise power spectral amplitudes at any frequencies are directly proportional to temperature. Hence, only one reference measurement at a known temperature is required for calibration. A complete MFFT thermometer system for the temperature range of ca. 4 K down to <10 mK is commercially available. We have now developed an integrated MFFT with an extended range of operation down to <1 mK. For this purpose the sensitivity of the SQUID sensor has been increased, the metal body geometry modified and the magnetic shielding of the MFFT module improved. These modifications make it possible to obtain a thermometer noise temperature of <10 μK. We discuss the rationale for our MFFT configuration and present numerical simulations and experimental results.

  3. Rotational population patterns and searches for the nuclear SQUID (Superconducting Quantum Interference Device)

    International Nuclear Information System (INIS)

    Canto, L.F.; Donangelo, R.J.; Farhan, A.R.; Guidry, M.W.; Rasmussen, J.O.; Ring, P.; Stoyer, M.A.

    1989-11-01

    This paper presents new theoretical results for rotational population patterns in the nuclear SQUID effect. (The term nuclear SQUID is in analogy to the solid-state Superconducting Quantum Interference Devices.) The SQUID effect is an interesting new twist to an old quest to understand Coriolis anti-pairing (CAP) effects in nuclear rotational bands. Two-neutron transfer reaction cross sections among high-spin states have long been touted as more specific CAP probes than other nuclear properties. Heavy projectiles like Sn or Pb generally are recommended to pump the deformed nucleus to as high spin as possible for transfer. The interference and sign reversal of 2n transfer amplitudes at high spin, as predicted in the early SQUID work imposes the difficult requirement of Coulomb pumping to near back-bending spins at closest approach. For Pb on rare earths we find a dramatic departure from sudden-approximation, so that the population depression occurs as low as final spin 10h. 14 refs., 8 figs

  4. Ocean Warming Enhances Malformations, Premature Hatching, Metabolic Suppression and Oxidative Stress in the Early Life Stages of a Keystone Squid

    Science.gov (United States)

    Rosa, Rui; Pimentel, Marta S.; Boavida-Portugal, Joana; Teixeira, Tatiana; Trübenbach, Katja; Diniz, Mário

    2012-01-01

    Background The knowledge about the capacity of organisms’ early life stages to adapt to elevated temperatures is very limited but crucial to understand how marine biota will respond to global warming. Here we provide a comprehensive and integrated view of biological responses to future warming during the early ontogeny of a keystone invertebrate, the squid Loligo vulgaris. Methodology/Principal Findings Recently-spawned egg masses were collected and reared until hatching at present day and projected near future (+2°C) temperatures, to investigate the ability of early stages to undergo thermal acclimation, namely phenotypic altering of morphological, behavioural, biochemical and physiological features. Our findings showed that under the projected near-future warming, the abiotic conditions inside the eggs promoted metabolic suppression, which was followed by premature hatching. Concomitantly, the less developed newborns showed greater incidence of malformations. After hatching, the metabolic burst associated with the transition from an encapsulated embryo to a planktonic stage increased linearly with temperature. However, the greater exposure to environmental stress by the hatchlings seemed to be compensated by physiological mechanisms that reduce the negative effects on fitness. Heat shock proteins (HSP70/HSC70) and antioxidant enzymes activities constituted an integrated stress response to ocean warming in hatchlings (but not in embryos). Conclusions/Significance The stressful abiotic conditions inside eggs are expected to be aggravated under the projected near-future ocean warming, with deleterious effects on embryo survival and growth. Greater feeding challenges and the lower thermal tolerance limits of the hatchlings are strictly connected to high metabolic demands associated with the planktonic life strategy. Yet, we found some evidence that, in the future, the early stages might support higher energy demands by adjusting some cellular functional properties

  5. Size increment of jumbo flying squid Dosidicus gigas mature females in Peruvian waters, 1989-2004

    Science.gov (United States)

    Argüelles, Juan; Tafur, Ricardo; Taipe, Anatolio; Villegas, Piero; Keyl, Friedeman; Dominguez, Noel; Salazar, Martín

    2008-10-01

    Changes in population structure of the jumbo flying squid Dosidicus gigas in Peruvian waters were studied based on size-at-maturity from 1989 to 2004. From 1989 to 1999, mature squid belonging to the medium-sized group prevailed, but from 2001 on, mature squids were larger. This change is not related to the changes in sea surface temperature and we hypothesized that it was caused by the population increase of mesopelagic fishes as prey.

  6. Biodiversity Patterns on an Inshore to Offshore Gradient Using Metabarcoding and Barcoding Molecular Tools

    KAUST Repository

    Villalobos Vazquez de la Parra, Rodrigo

    2015-12-01

    It has been estimated that coral reefs shelter 830 000 species. Well-studied biodiversity patterns provide tools for better representation of species in marine protected areas. A cross-shelf gradient in biodiversity exists for fishes, corals, and macroalgae. Here, an inshore to offshore gradient in biodiversity on the Saudi Arabian coast of the Red Sea was sampled using Autonomous Reef Monitoring Structures (ARMS) with barcoding and metabarcoding techniques. It was hypothesized that differences in community structure would be driven by an increase in habitat area. The difference was attributed to the greater accumulation of sediments close to shore that increases the area habitable for sediment dwelling organisms and favors macroalgal cover. Macroalgae are inhabited by a greater number of species than live coral. Only 10% of the sequences of the barcoded fraction and <1% of the metabarcoded fraction had a BLAST hit on the NCBI database with a previously identified species sequence. In addition, the rarefaction curves for all fractions did not plateau. The ARMS community composition changed from inshore to offshore and was significantly correlated with the percentage of algal and bryozoan plate cover. The differences in community composition were related to changes in habitat but not to sediments retrieved from the ARMS.

  7. Recent advancements in the SQUID magnetospinogram system

    Science.gov (United States)

    Adachi, Yoshiaki; Kawai, Jun; Haruta, Yasuhiro; Miyamoto, Masakazu; Kawabata, Shigenori; Sekihara, Kensuke; Uehara, Gen

    2017-06-01

    In this study, a new superconducting quantum interference device (SQUID) biomagnetic measurement system known as magnetospinogram (MSG) is developed. The MSG system is used for observation of a weak magnetic field distribution induced by the neural activity of the spinal cord over the body surface. The current source reconstruction for the observed magnetic field distribution provides noninvasive functional imaging of the spinal cord, which enables medical personnel to diagnose spinal cord diseases more accurately. The MSG system is equipped with a uniquely shaped cryostat and a sensor array of vector-type SQUID gradiometers that are designed to detect the magnetic field from deep sources across a narrow observation area over the body surface of supine subjects. The latest prototype of the MSG system is already applied in clinical studies to develop a diagnosis protocol for spinal cord diseases. Advancements in hardware and software for MSG signal processing and cryogenic components aid in effectively suppressing external magnetic field noise and reducing the cost of liquid helium that act as barriers with respect to the introduction of the MSG system to hospitals. The application of the MSG system is extended to various biomagnetic applications in addition to spinal cord functional imaging given the advantages of the MSG system for investigating deep sources. The study also includes a report on the recent advancements of the SQUID MSG system including its peripheral technologies and wide-spread applications.

  8. The bases for the development of high-temperature integrated SQUID-systems

    International Nuclear Information System (INIS)

    Polushkin, V.N.

    1992-01-01

    The current state of high-T c superconducting thin-film Josephson junctions and SQUIDs developing is reviewed. The prospects of application of new devices in supersensitive measurement apparatus are analyzed. It is shown that high T c SQUIDs are able seriously to influence further development of information and measurement engineering as on their base the series of microelectronic elements and devices of new generation can be built. 55 refs.; 7 figs.; 2 tabs

  9. A SQUID magnetometry system for a cryogenic neutron electric dipole moment experiment

    Energy Technology Data Exchange (ETDEWEB)

    Henry, S., E-mail: s.henry@physics.ox.ac.uk; Clarke, C.; Cottle, A.; Lynch, A.; Pipe, M.

    2014-11-01

    Precision magnetometry is an essential component of any neutron electric dipole moment experiment in order to correct shifts in the neutron precession frequency due to changes in the magnetic field. We have developed a magnetometry system using 12 SQUID sensors, designed to operate in 0.5 K superfluid helium. The pick-up loops located near the neutron cell are connected to the SQUID sensors by ∼2 m twisted wire pairs. The SQUID readout cables are run via an intermediate stage at 4.2 K. The system has been installed and tested in the cryoEDM apparatus at the ILL, Grenoble, and used to characterise the magnetic environment. Further tests in a suitable low noise environment confirm it meets our requirements.

  10. ULF-NMR system using HTS-SQUID and permanent magnet

    Energy Technology Data Exchange (ETDEWEB)

    Fukumoto, Shohei, E-mail: hatukade@ens.tut.ac.jp [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Tsunaki, Shingo; Chigasaki, Takumi; Hatsukade, Yoshimi; Tanaka, Saburo [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2013-01-15

    Highlights: ► A permanent magnet was introduced into a ULF SQUID-NMR system for polarization. ► An instrument to transfer a sample in the magnet to under a SQUID was implemented. ► An AC pulse coil was also introduced to apply a π/2 pulse to obtain an NMR signal. ► A {sup 1}H NMR signal was measured while applying a static field of 45 μT. ► The signal to noise ratio of the {sup 1}H NMR signal was about 100. -- Abstract: We have constructed an ultra-low field (ULF) nuclear magnetic resonance (NMR)/magnetic resonance imaging (MRI) system using an HTS-rf-SQUID and room-temperature electromagnets in a magnetically shielded room (MSR). In this study, in order to improve the signal to noise ratio (S/N) of the system, we introduced a permanent magnet instead of the electromagnet for pre-polarizing the sample to enhance the pre-polarizing field (B{sub p}). The cylindrical permanent magnet of 270 mT was used to magnetize a water sample for several seconds outside the MSR and about 1.5 m away from the SQUID. We constructed an instrument to transfer the magnetized sample from the permanent magnet to under the SQUID in 0.5 s. Since the non-adiabatic condition cannot be kept in such sample transfer scheme, an AC pulse coil to apply an AC pulse field B{sub AC} to rotate the magnetization moments for π/2 was introduced to measure a free induction decay (FID) signal from the sample. By this system, we obtained an NMR signal from the water sample of 10 ml while applying a static field of 45 μT and π/2 pulse after the transfer. The S/N of the NMR spectrum was about 100 by a single shot, which was 10 times larger than that obtained with the electromagnet of 32 mT. In addition, we demonstrated the measurements of the longitudinal relaxation time (T{sub 1}) and the spin echo signal of the water sample by the system.

  11. Reorganization of a marine trophic network along an inshore-offshore gradient due to stronger pelagic-benthic coupling in coastal areas

    Science.gov (United States)

    Kopp, Dorothée; Lefebvre, Sébastien; Cachera, Marie; Villanueva, Maria Ching; Ernande, Bruno

    2015-01-01

    Recent theoretical considerations have highlighted the importance of the pelagic-benthic coupling in marine food webs. In continental shelf seas, it was hypothesized that the trophic network structure may change along an inshore-offshore gradient due to weakening of the pelagic-benthic coupling from coastal to offshore areas. We tested this assumption empirically using the eastern English Channel (EEC) as a case study. We sampled organisms from particulate organic matter to predatory fishes and used baseline-corrected carbon and nitrogen stable isotope ratios (δ13C and δ15N) to determine their trophic position. First, hierarchical clustering on δ13C and δ15N coupled to bootstrapping and estimates of the relative contribution of pelagic and benthic carbon sources to consumers' diet showed that, at mesoscale, the EEC food web forms a continuum of four trophic levels with trophic groups spread across a pelagic and a benthic trophic pathway. Second, based on the same methods, a discrete approach examined changes in the local food web structure across three depth strata in order to investigate the inshore-offshore gradient. It showed stronger pelagic-benthic coupling in shallow coastal areas mostly due to a reorganization of the upper consumers relative to the two trophic pathways, benthic carbon sources being available to pelagic consumers and, reciprocally, pelagic sources becoming accessible to benthic species. Third a continuous approach examined changes in the mean and variance of upper consumers' δ13C and δ15N with depth. It detected a significant decrease in δ13C variance and a significant increase in δ15N variance as depth increases. A theoretical two-source mixing model showed that an inshore-offshore decrease in the pelagic-benthic coupling was a sufficient condition to produce the δ13C variance pattern, thus supporting the conclusions of the discrete approach. These results suggest that environmental gradients such as the inshore-offshore one should

  12. Can understanding squid life-history strategies and recruitment ...

    African Journals Online (AJOL)

    Can understanding squid life-history strategies and recruitment improve management? ... range of potentially limiting conditions in different years, they store genetic diversity and stabilize recruitment in time. ... AJOL African Journals Online.

  13. Reactive probing of macroscopically quantum mechanical SQUID rings

    International Nuclear Information System (INIS)

    Prance, R.J.; Clark, T.D.; Whiteman, R.; Diggins, J.; Ralph, J.F.; Prance, H.; Spiller, T.P.; Widom, A.; Srivastava, Y.

    1994-01-01

    In this paper we demonstrate that the energy level structure of ultra small capacitance SQUID rings can be probed adiabatically at radio frequency using both dynamical and quasistatic reactive techniques. ((orig.))

  14. Double-barrier junction based dc SQUID

    NARCIS (Netherlands)

    Bartolomé, M.E.; Brinkman, Alexander; Flokstra, Jakob; Golubov, Alexandre Avraamovitch; Rogalla, Horst

    2000-01-01

    dc SQUIDs based on double-barrier Nb/Al/AlOx/Al/AlOx/Al/Nb junctions (DBSQs) have been fabricated and tested for the first time. The current–voltage curves have been measured at temperatures down to 1.4 K. The critical current, Ic, dependence on the temperature T is partially described by the

  15. High-Tc SQUID Application for Roll to Roll Metallic Contaminant Detector

    International Nuclear Information System (INIS)

    Tanaka, S.; Kitamura, Y.; Uchida, Y.; Hatsukade, Y.; Ohtani, T.; Suzuki, S.

    2012-01-01

    A sensitive eight-channel high-Tc Superconducting Interference Device (SQUID) detection system for magnetic contaminant in a lithium ion battery anode was developed. Finding ultra-small metallic foreign matter is an important issue for a manufacturer because metallic contaminants carry the risk of an internal short. When contamination occurs, the manufacturer of the product suffers a great loss from recalling the tainted product. Metallic particles with outer dimensions smaller than 100 microns cannot be detected using a conventional X-ray imaging system. Therefore, a highly sensitive detection system for small foreign matter is required. We have already developed a detection system based on a single-channel SQUID gradiometer and horizontal magnetization. For practical use, the detection width of the system should be increased to at least 65 mm by employing multiple sensors. In this paper, we present an 8-ch high-Tc SQUID roll-to-roll system for inspecting a lithium-ion battery anode with a width of 65 mm. A special microscopic type of a cryostat was developed upon which eight SQUID gradiometers were mounted. As a result, small iron particles of 35 microns on a real lithium-ion battery anode with a width of 70 mm were successfully detected. This system is practical for the detection of contaminants in a lithium ion battery anode sheet.

  16. SiGe Integrated Circuit Developments for SQUID/TES Readout

    Science.gov (United States)

    Prêle, D.; Voisin, F.; Beillimaz, C.; Chen, S.; Piat, M.; Goldwurm, A.; Laurent, P.

    2018-03-01

    SiGe integrated circuits dedicated to the readout of superconducting bolometer arrays for astrophysics have been developed since more than 10 years at APC. Whether for Cosmic Microwave Background (CMB) observations with the QUBIC ground-based experiment (Aumont et al. in astro-ph.IM, 2016. arXiv:1609.04372) or for the Hot and Energetic Universe science theme with the X-IFU instrument on-board of the ATHENA space mission (Barret et al. in SPIE 9905, space telescopes & instrumentation 2016: UV to γ Ray, 2016. https://doi.org/10.1117/12.2232432), several kinds of Transition Edge Sensor (TES) (Irwin and Hilton, in ENSS (ed) Cryogenic particle detection, Springer, Berlin, 2005) arrays have been investigated. To readout such superconducting detector arrays, we use time or frequency domain multiplexers (TDM, FDM) (Prêle in JINST 10:C08015, 2016. https://doi.org/10.1088/1748-0221/10/08/C08015) with Superconducting QUantum Interference Devices (SQUID). In addition to the SQUID devices, low-noise biasing and amplification are needed. These last functions can be obtained by using BiCMOS SiGe technology in an Application Specific Integrated Circuit (ASIC). ASIC technology allows integration of highly optimised circuits specifically designed for a unique application. Moreover, we could reach very low-noise and wide band amplification using SiGe bipolar transistor either at room or cryogenic temperatures (Cressler in J Phys IV 04(C6):C6-101, 1994. https://doi.org/10.1051/jp4:1994616). This paper discusses the use of SiGe integrated circuits for SQUID/TES readout and gives an update of the last developments dedicated to the QUBIC telescope and to the X-IFU instrument. Both ASIC called SQmux128 and AwaXe are described showing the interest of such SiGe technology for SQUID multiplexer controls.

  17. SQUIDs as detectors in a new experiment to measure the neutron electric dipole moment

    International Nuclear Information System (INIS)

    Espy, M.A.; Cooper, M.; Lamoreaux, S.; Kraus, R.H. Jr.; Matlachov, A.; Ruminer, P.

    1998-01-01

    A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4x10 -28 ecm, a factor of 250 times better than the current experimental limit. Such a measure of the neutron EDM would challenge the theories of supersymmetry and time reversal violation as the origin of the observed cosmological asymmetry in the ratio of baryons to antibaryons. One possible design for this new experiment includes the use of LTC SQUIDs coupled to large (∼100 cm 2 ) pick-up coils to measure the precision frequency of the spin-polarized 3 He atoms that act as polarizer, spin analyzer, detector, and magnetometer for the ultra-cold neutrons used in the experiment. The method of directly measuring the 3 He precession signal eliminates the need for very uniform magnetic fields (a major source of systematic error in these types of experiments). It is estimated that a flux of ∼2x10 -16 Tm 2 (0.1 Φ 0 ) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of dΦ SQ = 2x10 -6 Φ 0 /√Hz at 10 Hz. While this is close to the sensitivity available in commercial devices, the effects of coupling to such a large pick-up coil and flux noise from other sources in the experiment still need to be understood. To determine the feasibility of using SQUIDs in such an application the authors designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and they developed a two-SQUID readout system that will reduce SQUID noise in the experiment. They present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. The authors also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique

  18. Ultra-sensitive sensors for weak electromagnetic fields using high-Tc SQUIDS for biomagnetism, NDE, and corrosion currents

    International Nuclear Information System (INIS)

    Kraus, R.H. Jr.; Flynn, E.R.; Espy, M.; Jia, Q.X.; Wu, X.D.; Reagor, D.

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The research has directly contributed to a new DOE supported project, three patents (one granted and two submitted), and several potential opportunities for new program funding at the Laboratory. The authors report significant developments extending from basic understanding of and fabrication techniques for high critical-temperature (high-T c ) SQUID devices to the development of high-level applications such as the SQUID Microscope. The development of ramp edge geometry and silver-doped YBa 2 Cu 3 O 7-x (YBCO) electrodes has tremendously improved the performance of high-T c SQUIDS. Recent experiments have proven and quantified the LANL-patented superconducting imaging plane gradiometry concept. A SQUID microscope, developed largely under this project, has recently acquired data that demonstrated exceptional sensitivity and resolution. New techniques for background noise suppression, needed to use the extraordinarily sensitive SQUID sensors in unshielded environments, have also been developed. Finally, initial investigations to use SQUIDs in a basic physics experiment to measure the electric dipole moment of the neutron were very successful

  19. Chronic Treatment with Squid Phosphatidylserine Activates Glucose Uptake and Ameliorates TMT-Induced Cognitive Deficit in Rats via Activation of Cholinergic Systems

    Directory of Open Access Journals (Sweden)

    Hyun-Jung Park

    2012-01-01

    Full Text Available The present study examined the effects of squid phosphatidylserine (Squid-PS on the learning and memory function and the neural activity in rats with TMT-induced memory deficits. The rats were administered saline or squid derived Squid-PS (Squid-PS 50 mg kg−1, p.o. daily for 21 days. The cognitive improving efficacy of Squid-PS on the amnesic rats, which was induced by TMT, was investigated by assessing the passive avoidance task and by performing choline acetyltransferase (ChAT and acetylcholinesterase (AchE immunohistochemistry. 18F-Fluorodeoxyglucose and performed a positron emission tomography (PET scan was also performed. In the passive avoidance test, the control group which were injected with TMT showed a markedly lower latency time than the non-treated normal group (P<0.05. However, treatment of Squid-PS significantly recovered the impairment of memory compared to the control group (P<0.05. Consistent with the behavioral data, Squid-PS significantly alleviated the loss of ChAT immunoreactive neurons in the hippocampal CA3 compared to that of the control group (P<0.01. Also, Squid-PS significantly increased the AchE positive neurons in the hippocampal CA1 and CA3. In the PET analysis, Squid-PS treatment increased the glucose uptake more than twofold in the frontal lobe and the hippocampus (P<0.05, resp.. These results suggest that Squid-PS may be useful for improving the cognitive function via regulation of cholinergic enzyme activity and neural activity.

  20. Direct readout flux locked loop circuit with automatic tuning of bias current and bias flux for high-Tc SQUID

    International Nuclear Information System (INIS)

    Hirano, T.; Nagaishi, T.; Itozaki, H.

    1999-01-01

    Measurement of high-frequency magnetic signals has been required from some SQUID applications. We fabricated a high-T c SQUID magnetic sensor system that can treat high-frequency signals. This system is composed of a SQUID, a preamplifier circuit, a flux locked loop (FLL) circuit with I/O and a personal computer and a PC card. We used the FLL circuit with no modulation to treat the high-frequency signal and to simplify the circuit. This system can treat a signal from dc to 1 MHz. All the sequence from tuning the SQUID to data acquisition can be done by a personal computer. This system successfully realized easy operation of SQUID measurement. (author)

  1. Expression of squid iridescence depends on environmental luminance and peripheral ganglion control.

    Science.gov (United States)

    Gonzalez-Bellido, P T; Wardill, T J; Buresch, K C; Ulmer, K M; Hanlon, R T

    2014-03-15

    Squid display impressive changes in body coloration that are afforded by two types of dynamic skin elements: structural iridophores (which produce iridescence) and pigmented chromatophores. Both color elements are neurally controlled, but nothing is known about the iridescence circuit, or the environmental cues, that elicit iridescence expression. To tackle this knowledge gap, we performed denervation, electrical stimulation and behavioral experiments using the long-fin squid, Doryteuthis pealeii. We show that while the pigmentary and iridescence circuits originate in the brain, they are wired differently in the periphery: (1) the iridescence signals are routed through a peripheral center called the stellate ganglion and (2) the iridescence motor neurons likely originate within this ganglion (as revealed by nerve fluorescence dye fills). Cutting the inputs to the stellate ganglion that descend from the brain shifts highly reflective iridophores into a transparent state. Taken together, these findings suggest that although brain commands are necessary for expression of iridescence, integration with peripheral information in the stellate ganglion could modulate the final output. We also demonstrate that squid change their iridescence brightness in response to environmental luminance; such changes are robust but slow (minutes to hours). The squid's ability to alter its iridescence levels may improve camouflage under different lighting intensities.

  2. Characterization of single-core magnetite nanoparticles for magnetic imaging by SQUID relaxometry

    International Nuclear Information System (INIS)

    Adolphi, Natalie L; Huber, Dale L; Monson, Todd C; Provencio, Paula P; Bryant, Howard C; Fegan, Danielle L; Tessier, Trace E; Flynn, Edward R; Lim, JitKang; Majetich, Sara A; Trujillo, Jason E; Lovato, Debbie M; Butler, Kimberly S; Larson, Richard S; Hathaway, Helen J

    2010-01-01

    Optimizing the sensitivity of SQUID (superconducting quantum interference device) relaxometry for detecting cell-targeted magnetic nanoparticles for in vivo diagnostics requires nanoparticles with a narrow particle size distribution to ensure that the Neel relaxation times fall within the measurement timescale (50 ms-2 s, in this work). To determine the optimum particle size, single-core magnetite nanoparticles (with nominal average diameters 20, 25, 30 and 35 nm) were characterized by SQUID relaxometry, transmission electron microscopy, SQUID susceptometry, dynamic light scattering and zeta potential analysis. The SQUID relaxometry signal (detected magnetic moment/kg) from both the 25 nm and 30 nm particles was an improvement over previously studied multi-core particles. However, the detected moments were an order of magnitude lower than predicted based on a simple model that takes into account the measured size distributions (but neglects dipolar interactions and polydispersity of the anisotropy energy density), indicating that improved control of several different nanoparticle properties (size, shape and coating thickness) will be required to achieve the highest detection sensitivity. Antibody conjugation and cell incubation experiments show that single-core particles enable a higher detected moment per cell, but also demonstrate the need for improved surface treatments to mitigate aggregation and improve specificity.

  3. Characterization of single-core magnetite nanoparticles for magnetic imaging by SQUID relaxometry

    Energy Technology Data Exchange (ETDEWEB)

    Adolphi, Natalie L [Department of Biochemistry and Molecular Biology, University of New Mexico, Albuquerque, NM 87131 (United States); Huber, Dale L; Monson, Todd C; Provencio, Paula P [Sandia National Laboratories, P. O. Box 5800, Albuquerque, NM 87185 (United States); Bryant, Howard C; Fegan, Danielle L; Tessier, Trace E; Flynn, Edward R [Senior Scientific, LLC, 11109 Country Club NE, Albuquerque, NM 87111 (United States); Lim, JitKang; Majetich, Sara A [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Trujillo, Jason E; Lovato, Debbie M; Butler, Kimberly S; Larson, Richard S [Department of Pathology, Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Hathaway, Helen J, E-mail: NAdolphi@salud.unm.ed [Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM 87131 (United States)

    2010-10-07

    Optimizing the sensitivity of SQUID (superconducting quantum interference device) relaxometry for detecting cell-targeted magnetic nanoparticles for in vivo diagnostics requires nanoparticles with a narrow particle size distribution to ensure that the Neel relaxation times fall within the measurement timescale (50 ms-2 s, in this work). To determine the optimum particle size, single-core magnetite nanoparticles (with nominal average diameters 20, 25, 30 and 35 nm) were characterized by SQUID relaxometry, transmission electron microscopy, SQUID susceptometry, dynamic light scattering and zeta potential analysis. The SQUID relaxometry signal (detected magnetic moment/kg) from both the 25 nm and 30 nm particles was an improvement over previously studied multi-core particles. However, the detected moments were an order of magnitude lower than predicted based on a simple model that takes into account the measured size distributions (but neglects dipolar interactions and polydispersity of the anisotropy energy density), indicating that improved control of several different nanoparticle properties (size, shape and coating thickness) will be required to achieve the highest detection sensitivity. Antibody conjugation and cell incubation experiments show that single-core particles enable a higher detected moment per cell, but also demonstrate the need for improved surface treatments to mitigate aggregation and improve specificity.

  4. Image processing for HTS SQUID probe microscope

    International Nuclear Information System (INIS)

    Hayashi, T.; Koetitz, R.; Itozaki, H.; Ishikawa, T.; Kawabe, U.

    2005-01-01

    An HTS SQUID probe microscope has been developed using a high-permeability needle to enable high spatial resolution measurement of samples in air even at room temperature. Image processing techniques have also been developed to improve the magnetic field images obtained from the microscope. Artifacts in the data occur due to electromagnetic interference from electric power lines, line drift and flux trapping. The electromagnetic interference could successfully be removed by eliminating the noise peaks from the power spectrum of fast Fourier transforms of line scans of the image. The drift between lines was removed by interpolating the mean field value of each scan line. Artifacts in line scans occurring due to flux trapping or unexpected noise were removed by the detection of a sharp drift and interpolation using the line data of neighboring lines. Highly detailed magnetic field images were obtained from the HTS SQUID probe microscope by the application of these image processing techniques

  5. Radio frequency interference noise reduction using a field programmable gate array for SQUID applications

    International Nuclear Information System (INIS)

    Sakuta, K; Narita, Y; Itozaki, H

    2007-01-01

    It is important to remove large environmental noise in superconducting quantum interference device (SQUID) measurement without magnetic shielding. Active noise control (ANC) is one of the effective methods to reduce environmental noise. Recently, SQUIDs have been used in various applications at high frequencies, such as nuclear quadrupole resonance (NQR). The NQR frequency from explosives is in the range 0.5-5 MHz. In this case, an NQR sensor is exposed to AM radio frequency interference (RFI). The feasibility of the ANC system for RFI that used digital signal processing was studied. Our investigation showed that this digital ANC system can be applied to SQUID measurements for RFI suppression

  6. One Period of Exploration with the Squid.

    Science.gov (United States)

    Bradley, James V.; Ng, Andrew

    1997-01-01

    Presents a lab that can be offered after students have learned the basic anatomy and physiology of the various phyla, the primary objective of which is to explore and apply their acquired knowledge to a new situation. Involves exploring the anatomy and life-style of the squid. (JRH)

  7. Loligo gahi, the Patagonian longfin squid, has been the subject of a ...

    African Journals Online (AJOL)

    spamer

    the FIFD by the Renewable Resources Assessment. Group (RRAG) at Imperial College, London (FIFD. 1989). Assessments of Illex argentinus around the. Falkland Islands made using Delury depletion models have proved to be complex but tractable (Beddington et al. 1990, Rosenberg et al. 1990, Basson et al. 1996).

  8. Rapid Associative Learning and Stable Long-Term Memory in the Squid Euprymna scolopes.

    Science.gov (United States)

    Zepeda, Emily A; Veline, Robert J; Crook, Robyn J

    2017-06-01

    Learning and memory in cephalopod molluscs have received intensive study because of cephalopods' complex behavioral repertoire and relatively accessible nervous systems. While most of this research has been conducted using octopus and cuttlefish species, there has been relatively little work on squid. Euprymna scolopes Berry, 1913, a sepiolid squid, is a promising model for further exploration of cephalopod cognition. These small squid have been studied in detail for their symbiotic relationship with bioluminescent bacteria, and their short generation time and successful captive breeding through multiple generations make them appealing models for neurobiological research. However, little is known about their behavior or cognitive ability. Using the well-established "prawn-in-the-tube" assay of learning and memory, we show that within a single 10-min trial E. scolopes learns to inhibit its predatory behavior, and after three trials it can retain this memory for at least 12 d. Rapid learning and very long-term retention were apparent under two different training schedules. To our knowledge, this study is the first demonstration of learning and memory in this species as well as the first demonstration of associative learning in any squid.

  9. A three-axis SQUID-based absolute vector magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Schönau, T.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, H.-G. [Department of Quantum Detection, Leibniz Institute of Photonic Technology, Jena 07745 (Germany); Zakosarenko, V.; Meyer, M. [Supracon AG, An der Lehmgrube 11, Jena 07751 (Germany)

    2015-10-15

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz{sup 1/2}. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  10. Fishery biology of jumbo flying squid Dosidicus gigas off Costa Rica Dome

    Science.gov (United States)

    Chen, Xinjun; Li, Jianghua; Liu, Bilin; Li, Gang; Lu, Huajie

    2014-06-01

    The jumbo flying squid ( Dosidicus gigas) population was surveyed with the help of Chinese squid jigging vessels off the Costa Rica Dome (4°-11°N, 90°-100°W) in 2009 and 2010. The daily catch of D. gigas in the two survey cruises ranged from 0 to 5.5 t and was mostly obtained from the areas bounded by 6°-9°N and 91°-94°W and by 6°30'-7°30'N and 96°-97°W. The sea surface temperature in the areas yielding the most catch ranged from 27.5 to 29°C. The sex ratio of the total catch was 3.75:1 (female: male). The mantle length of the squid ranged from 211 to 355 mm (male) and from 204 to 429 mm (female) with an average of 297.9 and 306.7 mm, respectively. In the relationship of the mantle length (mm) and body weight (g) of the squid, there was no significant difference between sexes. The female and male were at a similar maturity, and most individuals are maturing or have matured with a few females being spent. The size (mantle length) and age at the first sexual maturity were 297 mm and 195 d in females, and less than 211 mm and 130 d in males, respectively. Most of the sampled stomachs (70.6%) had no food remains. The major preys of the squids were fish, cephalopods and crustaceans, with the most abundant Myctophum orientale and D. gigas. The preys in more than 65% of the non-empty sampled stomachs evidenced the cannibalism of D. gigas. The results improved current understanding of the fishery biology of D. gigas off the Costa Rica Dome, which may facilitate the assessment and management of relative fishery resources.

  11. Influence of gamma irradiation and low temperature storage on the quality and shelf life of squid (Doryteuthis sibogae

    Directory of Open Access Journals (Sweden)

    Manjanaik, B.

    2017-08-01

    Full Text Available Irradiation is considered as an efficient method for the reduction of microorganisms in food. It has been used to improve the safety and shelf life of food products. The present investigation is aimed at studying the influence of gamma irradiation (3 and 5 kGy and subsequent storage at refrigeration temperature (4oC on the chemical, microbial qualities and extended shelf life of squid (Doryteuthis sibogae. The total volatile base nitrogen (TVB-N and trimethyl amine nitrogen values (TMA-N of the irradiated squid samples significantly decreased in comparison with the control (non-irradiated stored at 4oC. The thiobarbituric acid values for the irradiated squid was significantly lower than of the non-irradiated samples stored at 4oC (p<0.05. The pH value of the squid was affected significantly by both, irradiation dose and storage temperature (p<0.05. The total microbial load for the non-irradiated squid samples was higher than those of irradiated samples at 4oC temperature. The results revealed that the combination of irradiation and refrigerated storage resulted in a significant reduction of microbial growth and stabilized the biochemical characteristics of squid.

  12. Inshore craft traditional working vessels of the british isles

    CERN Document Server

    Greenhill, Basil

    2013-01-01

    This comprehensive reference work describes and illustrates some 200 types of inshore craft that once fished and traded, under oar and sail, around the coasts of the British Isles. The types are arranged by coastal area and each is described in terms of its shape and design, fitness for location and purpose, build, evolution and geographical distribution. Details of dimensions, rig, building materials, seamanship and the survival of examples are given where known, while hundreds of line drawings and photographs show the vessels in their original forms.A team of twelve experts describe all these boat types and, in addition, there are introductions to the main geographic areas outlining the physical environments, fisheries and other uses of the sea that have influenced boat design; maps of all the areas show ports and physical features.At the beginning of the last century sail and oar dominated fisheries and local trade: one hundred years later those craft have all but vanished. This book brings alive for marit...

  13. HTS-SQUID NDE Technique for Pipes based on Ultrasonic Guided Wave

    International Nuclear Information System (INIS)

    Hatsukade, Y; Masutani, N; Teranishi, S; Masamoto, K; Kanenaga, S; Adachi, S; Tanabe, K

    2017-01-01

    This article describes research on the novel high-temperature superconductor (HTS) superconducting quantum interference device (SQUID) non-destructive evaluation (NDE) technique for metallic pipes based on ultrasonic guided waves. We constructed HTS-SQUID NDE system for pipes based on ultrasonic guided waves, which were generated and received by means of the magnetostrictive effects. Using the system, we measured magnetic signals due to T (0, 1) mode ultrasonic guided waves that transmitted on aluminium pipe, and investigated influences of measurement parameters to the magnetic signals, such as direction of a HTS-SQUID gradiometer, lift-off distance, and intensity and frequency of input current fed to a magnetostrictive transmitter. With the gradiometer oriented parallel to the pipe axis, more than 10 times larger signals were measured compared with that oriented perpendicular to the pipe axis. Magnetic signals measured by the gradiometer were inverse proportional to the power of the list- off distance, and proportional to the intensity of the input current up to 1 A pp . Relation between the frequency of the input current and the measured signal was shown and discussed. (paper)

  14. HTS-SQUID NDE Technique for Pipes based on Ultrasonic Guided Wave

    Science.gov (United States)

    Hatsukade, Y.; Masutani, N.; Teranishi, S.; Masamoto, K.; Kanenaga, S.; Adachi, S.; Tanabe, K.

    2017-07-01

    This article describes research on the novel high-temperature superconductor (HTS) superconducting quantum interference device (SQUID) non-destructive evaluation (NDE) technique for metallic pipes based on ultrasonic guided waves. We constructed HTS-SQUID NDE system for pipes based on ultrasonic guided waves, which were generated and received by means of the magnetostrictive effects. Using the system, we measured magnetic signals due to T (0, 1) mode ultrasonic guided waves that transmitted on aluminium pipe, and investigated influences of measurement parameters to the magnetic signals, such as direction of a HTS-SQUID gradiometer, lift-off distance, and intensity and frequency of input current fed to a magnetostrictive transmitter. With the gradiometer oriented parallel to the pipe axis, more than 10 times larger signals were measured compared with that oriented perpendicular to the pipe axis. Magnetic signals measured by the gradiometer were inverse proportional to the power of the list- off distance, and proportional to the intensity of the input current up to 1 App. Relation between the frequency of the input current and the measured signal was shown and discussed.

  15. Low-frequency nuclear quadrupole resonance with a dc SQUID

    International Nuclear Information System (INIS)

    Chang, J.W.

    1991-07-01

    Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs

  16. The squid-Vibrio symbioses: from demes to genes.

    Science.gov (United States)

    Kimbell, Jennifer R; McFall-Ngai, Margaret J

    2003-04-01

    The monospecific light organ association between the Hawaiian sepiolid squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri has been used as a model for the study of the most common type of coevolved animal-bacterial interaction; i.e., the association of Gram-negative bacteria with the extracellular apical surfaces of polarized epithelia. Analysis of the squid-vibrio symbiosis has ranged from characterizations of the harvesting mechanisms by which the host ensures colonization by the appropriate symbiont to identification of bacteria-induced changes in host gene expression that accompany the establishment and maintenance of the relationship. Studies of this model have been enhanced by extensive collaboration with microbiologists, who are able to manipulate the genetics of the bacterial symbiont. The results of our studies have indicated that initiation and persistence of the association requires a complex, reciprocal molecular dialogue between these two phylogenetically distant partners.

  17. Apparatus and method for detecting a magnetic anomaly contiguous to remote location by SQUID gradiometer and magnetometer systems

    Science.gov (United States)

    Overton, W.C. Jr.; Steyert, W.A. Jr.

    1981-05-22

    A superconducting quantum interference device (SQUID) magnetic detection apparatus detects magnetic fields, signals, and anomalies at remote locations. Two remotely rotatable SQUID gradiometers may be housed in a cryogenic environment to search for and locate unambiguously magnetic anomalies. The SQUID magnetic detection apparatus can be used to determine the azimuth of a hydrofracture by first flooding the hydrofracture with a ferrofluid to create an artificial magnetic anomaly therein.

  18. Thermodynamics of a closed-cycle gas flow system for cooling a HTc dc-SQUID magnetometer

    NARCIS (Netherlands)

    van den Bosch, P.J.; van den Bosch, P.J.; ter Brake, Hermanus J.M.; van den Eijkel, G.C.; Boelens, J.P.; Holland, Herman J.; Verberne, J.F.C.; Rogalla, Horst

    1994-01-01

    A multichannel high-Tc dc-SQUID based heart-magnetometer is currently under development in our laboratory. The system is cooled by a cooler that, due to its magnetic interference, has to be separated from the SQUID unit. In the present prototype system a closed-cycle gas flow was chosen as the

  19. Conversion of Squid Pens to Chitosanases and Proteases via Paenibacillus sp. TKU042

    Directory of Open Access Journals (Sweden)

    Chien Thang Doan

    2018-03-01

    Full Text Available Chitosanases and proteases have received much attention due to their wide range of applications. Four kinds of chitinous materials, squid pens, shrimp heads, demineralized shrimp shells and demineralized crab shells, were used as the sole carbon and nitrogen (C/N source to produce chitosanases, proteases and α-glucosidase inhibitors (αGI by four different strains of Paenibacillus. Chitosanase productivity was highest in the culture supernatants using squid pens as the sole C/N source. The maximum chitosanase activity of fermented squid pens (0.759 U/mL was compared to that of fermented shrimp heads (0.397 U/mL, demineralized shrimp shells (0.201 U/mL and demineralized crab shells (0.216 U/mL. A squid pen concentration of 0.5% was suitable for chitosanase, protease and αGI production via Paenibacillus sp. TKU042. Multi-purification, including ethanol precipitation and column chromatography of Macro-Prep High S as well as Macro-Prep DEAE (diethylaminoethyl, led to the isolation of Paenibacillus sp. TKU042 chitosanase and protease with molecular weights of 70 and 35 kDa, respectively. For comparison, 16 chitinolytic bacteria, including strains of Paenibacillus, were investigated for the production of chitinase, exochitinase, chitosanase, protease and αGI using two kinds of chitinous sources.

  20. Potential use of stable isotope and fatty acid analyses for traceability of geographic origins of jumbo squid (Dosidicus gigas).

    Science.gov (United States)

    Gong, Yi; Li, Yunkai; Chen, Xinjun; Chen, Ling

    2018-04-15

    Squid is an important seafood resource for Asian and European countries. With the continuous development of processed squid products, an effective traceability system has become increasingly prominent. Here, we attempt to trace the fishery products of the main target species, jumbo squid (Dosidicus gigas), by using biochemical tracers. Carbon and nitrogen isotope ratios (δ 13 C and δ 15 N values) and fatty acid profiles were identified in squid from three harvest locations in the eastern Pacific Ocean by isotope ratio mass spectrometry and gas chromatography/mass spectrometry, respectively. Comparative analysis was used to evaluate the geographic variations in tracers and to identify the suitable discriminatory variables among origins. Significant spatial variations were found in isotopic values and fatty acid profiles in squid muscle tissues, possibly because of different food availability and/or oceanographic conditions that each group experiences at a given location. The stepwise discriminant analysis indicated that δ 15 N, C16:1n7, C17:1n7, C18:2n6, C20:1 and C20:4n6 were effective variables at differentiating origin. Combined use of stable isotope ratios and fatty acid analyses could trace geographic origins of jumbo squid. This study provides an alternative approach for improving authenticity evaluation of commercial squid products. Copyright © 2018 John Wiley & Sons, Ltd.

  1. Magnetic evaluation of a solar panel using HTS-SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Kiwa, Toshihiko, E-mail: kiwa@okayama-u.ac.jp; Fukudome, Yohei; Miyazaki, Shingo; Saari, Mohd Mawardi; Sakai, Kenji; Tsukada, Keiji

    2013-11-15

    Highlights: •The magnetic evaluation system of a solar panel using HTS-SQUID has been developed. •The electric circuits made by the discrete devices on the circuit board were visualized. •The electric properties of the commercial solar panels were demonstrated. -- Abstract: The magnetic evaluation system of a solar panel using HTS-SQUID has been proposed and developed. A normal pick-up coil was applied to detect the tangential magnetic field to the panel surface. Since the detected field could be related to the currents of the solar panels, the electric properties of the solar panels could be evaluated. In this work, the evaluation of the electric properties of the commercial solar panels as well as the electric circuits made by the discrete devices on the circuit board was visualized.

  2. Magnetic evaluation of a solar panel using HTS-SQUID

    International Nuclear Information System (INIS)

    Kiwa, Toshihiko; Fukudome, Yohei; Miyazaki, Shingo; Saari, Mohd Mawardi; Sakai, Kenji; Tsukada, Keiji

    2013-01-01

    Highlights: •The magnetic evaluation system of a solar panel using HTS-SQUID has been developed. •The electric circuits made by the discrete devices on the circuit board were visualized. •The electric properties of the commercial solar panels were demonstrated. -- Abstract: The magnetic evaluation system of a solar panel using HTS-SQUID has been proposed and developed. A normal pick-up coil was applied to detect the tangential magnetic field to the panel surface. Since the detected field could be related to the currents of the solar panels, the electric properties of the solar panels could be evaluated. In this work, the evaluation of the electric properties of the commercial solar panels as well as the electric circuits made by the discrete devices on the circuit board was visualized

  3. Natural mortality estimation and rational exploitation of purpleback flying squid Sthenoteuthis oualaniensis in the southern South China Sea

    Science.gov (United States)

    Wang, Xuehui; Qiu, Yongsong; Zhang, Peng; Du, Feiyan

    2017-07-01

    Based on the biological data of purpleback flying squid ( Sthenoteuthis oualaniensis) collected by light falling-net in the southern South China Sea (SCS) during September to October 2012 and March to April 2013, growth and mortality of `Medium' and `Dwarf' forms of squid are derived using the Powell-Wetherall, ELEFAN methods and length-converted catch curves (FiSAT package). Given a lack of commercial exploitation, we assume total mortality to be due entirely to natural mortality. We estimate these squid have fast growth, with growth coefficients ( k) ranging from 1.42 to 2.39, and high natural mortality ( M), with estimates ranging from 1.61 to 2.92. To sustainably exploit these squid stocks, yield per recruitment based on growth and natural mortality was determined using the Beverton-Holt dynamic pool model. We demonstrate squid stocks could sustain high fishing mortality and low ages at first capture, with an optimal fishing mortality >3.0, with the optimal age at first capture increased to 0.4-0.6 years when fishing mortality approached optimal levels. On the basis of our analyses and estimates of stock biomass, we believe considerable potential exists to expand the squid fishery into the open SCS, relieving fishing pressure on coastal waters.

  4. Simulation and optimization of a dc SQUID with finite capacitance

    Energy Technology Data Exchange (ETDEWEB)

    de Waal, V.J.; Schrijner, P.; Llurba, R.

    1984-02-01

    This paper deals with the calculations of the noise an the optimization of the energy resolution of a dc SQUID with finite junction capacitance. Up to now noise calculations of dc SQUIDs were performed using a model without parasitic capacitances across the Josephson junctions. As the capacitances limit the performance of the SQUID, for a good optimization one must take them into account. The model consists of two coupled nonlinear second-order differential equations. The equations are very suitable for simulation with an analog circuit. We implemented the model on a hybrid computer. The noise spectrum from the model is calculated with a fast Fourier transform. A calculation of the energy resolution for one set of parameters takes about 6 min of computer time. Detailed results of the optimization are given for products of inductance and temperature of LT = 1.2 and 5 nHK. Within a range of ..beta.. and ..beta../sub c/ between 1 and 2, which is optimum, the energy resolution is nearly independent of these variables. In this region the energy resolution is near the value calculated without parasitic capacitances. Results of the optimized energy resolution are given as a function of LT between 1.2 and 10 nHK.

  5. Simulation and optimization of a dc SQUID with finite capacitance

    Science.gov (United States)

    de Waal, V. J.; Schrijner, P.; Llurba, R.

    1984-02-01

    This paper deals with the calculations of the noise and the optimization of the energy resolution of a dc SQUID with finite junction capacitance. Up to now noise calculations of dc SQUIDs were performed using a model without parasitic capacitances across the Josephson junctions. As the capacitances limit the performance of the SQUID, for a good optimization one must take them into account. The model consists of two coupled nonlinear second-order differential equations. The equations are very suitable for simulation with an analog circuit. We implemented the model on a hybrid computer. The noise spectrum from the model is calculated with a fast Fourier transform. A calculation of the energy resolution for one set of parameters takes about 6 min of computer time. Detailed results of the optimization are given for products of inductance and temperature of LT=1.2 and 5 nH K. Within a range of β and β c between 1 and 2, which is optimum, the energy resolution is nearly independent of these variables. In this region the energy resolution is near the value calculated without parasitic capacitances. Results of the optimized energy resolution are given as a function of LT between 1.2 and 10 mH K.

  6. Studies on the effect of low dose gamma irradiation on the chemical, microbial quality and shelf life of squid

    International Nuclear Information System (INIS)

    Bojayanaik, Manjanaik; Naroth, Kavya; Shetty, Veena; Hiriyur, Somashekarappa

    2014-01-01

    The present investigation was carried out to study the combined effect of low dose gamma irradiation (1, 3 and 5 kGy) and storage at refrigeration (+4℃) and frozen (-18℃) temperatures, on the shelf life extension of fresh squid. The study was based on microbiological and physico-chemical changes occurring in the squid samples. The biochemical parameters such as total volatile base nitrogen and trimethyl amine nitrogen values for irradiated squid samples were significantly lower than non-irradiated samples at both storage temperatures and the rate of decrease was more pronounced in samples irradiated at the higher dose of 3 and 5 kGy (p<0.05). pH values of squid samples were affected by both irradiation dose and storage temperature (p<0.05). Total microbial load for non- irradiated (control) squid samples were higher than the respective irradiated samples at both storage temperatures. The results revealed that the combination of irradiation and low temperature storage resulted in a significant reduction of microbial growth and extend the shelf life of squid at refrigeration and frozen temperature to about 12 and 90 days respectively. (author)

  7. Influence of inductance induced noise in an YBa2Cu3O7 dc-SQUID at high operation temperatures

    DEFF Research Database (Denmark)

    Nilsson, P. Å.; Claeson, T.; Hansen, J. B.

    1994-01-01

    The voltage modulation depth of a high T(c) dc-SQUID was measured at temperatures close to T(c) and compared to a model by Enpuku et al. where the flux noise from the SQUID inductance is taken into account. The device was an YBa2Cu3O7 dc-SQUID made on a bicrystal substrate of SrTiO3. The design w...

  8. Dynamics of d-wave YBa{sub 2}Cu{sub 3}O{sub 7-x} dc SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Bauch, T [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Cedergren, K [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Johansson, J [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Rotoli, G [Dipartimento di Ingeneria Meccanica, Energetica e Gestionale, Universita of L' Aquila, Localita Moneluco, L' Aquila (Italy); Tafuri, F [Dipartimento Ingeneria dell' Informatione, INFM, Seconda Universita di Napoli, Aversa (Italy); Lombardi, F [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden)

    2007-02-15

    The predominant d-wave pairing symmetry in high temperature superconductors leads to an unconventional current-phase relation in Josephson junctions. This circumstance may induce new effects in the dynamics of dc SQUIDs. In this contribution we report on the measurements of the dependence of the SQUID Josephson current on the external magnetic field taken at very low temperatures, down to 20 mK. Different grain boundaries have been fabricated by using the biepitaxial and the bicrystal technique. Some of the effects which are induced by a nonsinusoidal current-phase relation can be clearly identified in the dynamics of the SQUIDs. The experimental data are also compared with theoretical simulations taking into account the inductance of the loop. The data show that, in specific conditions, a non-negligible inductance of the loop can induce effects similar to an unconventional current-phase relation, with a pronounced second harmonic sin(2{psi}) term. This fact has to be taken into account when designing d-wave SQUIDs for quantum circuitry.

  9. Squid measurement of the Verwey transition on epitaxial (1 0 0) magnetite thin films

    International Nuclear Information System (INIS)

    Dediu, V.; Arisi, E.; Bergenti, I.; Riminucci, A.; Solzi, M.; Pernechele, C.; Natali, M.

    2007-01-01

    We report results on epitaxial magnetite (Fe 3 O 4 ) thin films grown by electron beam ablation on (1 0 0) MgAl 2 O 4 substrates. At 120 K magnetite undergoes a structural and electronic transition, the so-called Verwey transition, at which magnetic and conducting properties of the material change. We observed the Verwey transition on epitaxial films with a thickness of 50 nm by comparing zero-field cooling (ZFC) and field cooling (FC) curves measured with a superconducting quantum interference device (SQUID) magnetometer. Observation of the Verwey transition by SQUID measurements in the films is sign of their high crystalline quality. Room temperature ferromagnetism has also been found by magneto-optical Kerr rotation (MOKE) and confirmed by SQUID measurements, with a hysteresis loop showing a coercive field of hundreds of Oe

  10. 76 FR 68642 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-11-07

    ... update to essential fish habitat designations for all life stages of mackerel, longfin squid, Illex squid... issued a mackerel permit may not fish for, possess, or land more than 20,000 lb (9.08 mt) of mackerel per trip, and that, during any closure that occurs after June 1, vessels may not fish for, possess, or land...

  11. SQUID magnetometry and magneto-optics of epitaxial EuS

    International Nuclear Information System (INIS)

    Rumpf, K.; Granitzer, P.; Krenn, H.; Kellner, W.; Pascher, H.; Kirchschlager, R.; Janecek, S.

    2004-01-01

    The complicated (H,T)-magnetic phase diagram of EuS is caused by the critical balance between nearest and next nearest neighbour exchange interaction (J NN = 0.119 K and J NNN =-0.1209 K) and leads to various spin arrangements NNSS..., NSN..., NNS, NNN... [NS denotes opposite ferromagnetic order in adjacent (111) planes]. Beside the subtle local exchange of 5d-t 2g electrons and localized holes with neighbouring Eu-4f spins, obviously also the strain status influences the occurrence of these different phases. We investigate the magnetic ordering phenomenon in a strained 2.5 μm EuS film on BaF 2 substrate by SQUID magnetometry and magneto-optics like spectral Faraday- and Kerr-effect measurements for temperatures from 2 K up to 200 K and for magnetic field up to 5 T. The magneto-optical probe monitors the local environment of the photoexcited electron-hole pair, called magnetic exciton, located within a ferromagnetic surrounding (photoinduced magnetic polaron), whereas the integral magnetization measured by SQUID is most sensitive to long-range magnetic ordering. In spite of the dissimilarity of measurement techniques we find an influence of the long-range magnetic order (e.g. of the NNS- or NNN-matrix) on the non-resonant Kerr reflection. The complementarity of SQUID and magneto-optical methods is stringent only in the (resonant) spectral range, where magnetic polarons are formed. (author)

  12. Plan for SQUID microscope at ASRC: Vision, purposes and the present status

    International Nuclear Information System (INIS)

    Kadowaki, K.; Kakeya, I.; Suzuki, J.; Hata, Y.; Hojyo, K

    2001-01-01

    A new research plan to develop SQUID microscope and apply it to advanced science and technology research was started in the year of 2000 at the Advanced Science Research Center (ASRC) of JAERI (Japan Atomic Energy Research Institute). This plan was made to develop 'research of ultrafine magnetic structures with magnetic microscope' and is scheduled to continue five years. Principle of SQUID magnetic microscope is to observe changes of magnetic field in microscopic space using SQUID element as the magnetic probe. At present this type of instrument is fabricated by Seiko Instruments Inc. in Japan and is commercially available. Therefore, this plan is being promoted in collaboration with Seiko Instruments Inc. One of the main issues of the present plan is to raise the spatial resolution to the extremity. As of magnetic microscopes, 'magnetic force microscope' and 'scanning Hall probe microscope' also exist. They have different characteristics of their own. The present plan needs challenging technical developments in various fields. Supposed the spatial resolution be made very high, for example, by making very fine SQUID loop with ultrafine processing, critical technologies like sensitivity, electronics, quantum size effect and so on are to be solved at the same time. Characteristics of the existing instrument are being examined from various aspects. At present, the following three issues are taken up and being studied. (1) High resolution and related technical developments. (2) High sensitivity. (3) High performance of cooling system. Among them, the high resolution is the most serious problem. Completely new design of the SQUID system may be needed. By using the existing instrument, magnetic fluxes trapped on YBCO films are observed and the image quality is being examined. Some of the issues which are considered to be taken up now are listed as follows. (1) Magnetic domain structures on thin film magnetic materials. (2) Observation of structures of Josephson magnetic

  13. High-Tc SQUID gradiometer system for magnetocardiography in an unshielded environment

    International Nuclear Information System (INIS)

    Liao, S H; Hsu, S C; Lin, C C; Horng, H E; Chen, J C; Chen, M J; Wu, C H; Yang, H C

    2003-01-01

    We set up an electronic gradiometer for magnetocardiography (MCG) in an unshielded environment. The electronically balanced gradiometer consists of high-temperature radio-frequency superconducting quantum interference device (rf SQUID) magnetometers. The rf SQUID magnetometers are arranged to form the electronic first-order, four-vector gradiometer, or second-order gradiometer. The output of the MCG signal was filtered by a band pass (1-30 Hz) and power line filters. We can reduce the noise to ∼1 pT Hz -1/2 at 1 Hz for second-order or four-vector gradiometers. Two-dimensional MCG imaging is demonstrated. The results are discussed with data measured in the moderate magnetically shielded environment

  14. Effect of thermal processing and canning on cadmium and lead levels in California market squid: the role of metallothioneins.

    Science.gov (United States)

    Galitsopoulou, A; Georgantelis, D; Kontominas, M G

    2013-01-01

    The effects of two common seafood preparation practices (roasting and industrial canning) on the heavy metal content--cadmium (Cd) and lead (Pb)--of various tissues of California market squid were studied. Emphasis was placed on the role of metallothioneins (MT) in Cd and Pb behaviour during processing. Cd and Pb analysis was conducted by a Zeeman GTA-AAS atomic absorption spectrometry system; MT analysis was performed by a mercury saturation assay. Results showed that Cd levels in the mantle and whole squid were considerably affected by both processing practices, reaching a 240% increase in mantle and a 40% increase in whole squid. Interestingly, Cd behaviour was associated with MT changes during squid processing. On the other hand, Pb content was not affected from either processing or associated with MT content in the raw or processed squid. Therefore, processing operations may affect Cd and Pb content differently due to the specific metal bioaccumulation and chemical features of each heavy metal type.

  15. The male reproductive strategy of a deep-sea squid : sperm allocation, continuous production, and long-term storage of spermatophores in Histioteuthis miranda

    NARCIS (Netherlands)

    Hoving, Hendrik Jan T.; Lipinski, Marek R.; Dam, Lammertjan

    2010-01-01

    Squid are semelparous organisms. Much of what we know about squid reproduction relates to females, because few studies have addressed males and, although males are similarly challenged by semelparity, it remains virtually unknown what tactics squid have evolved to allocate sperm to spermatophores.

  16. Ultraviolet Laser SQUID Microscope for GaN Blue Light Emitting Diode Testing

    International Nuclear Information System (INIS)

    Daibo, M; Kamiwano, D; Kurosawa, T; Yoshizawa, M; Tayama, N

    2006-01-01

    We carried out non-contacting measurements of photocurrent distributions in GaN blue light emitting diode (LED) chips using our newly developed ultraviolet (UV) laser SQUID microscope. The UV light generates the photocurrent, and then the photocurrent induces small magnetic fields around the chip. An off-axis arranged HTS-SQUID magnetometer is employed to detect a vector magnetic field whose typical amplitude is several hundred femto-tesla. Generally, it is difficult to obtain Ohmic contacts for p-type GaN because of the low hole concentration in the p-type epitaxial layer and the lack of any available metal with a higher work function compared with the p-type GaN. Therefore, a traditional probecontacted electrical test is difficult to conduct for wide band gap semiconductors without an adequately annealed electrode. Using the UV-laser SQUID microscope, the photocurrent can be measured without any electrical contact. We show the photocurrent vector map which was reconstructed from measured magnetic fields data. We also demonstrate how we found the position of a defect of the electrical short circuits in the LED chip

  17. Seasonal Habitat Patterns of Japanese Common Squid (Todarodes Pacificus Inferred from Satellite-Based Species Distribution Models

    Directory of Open Access Journals (Sweden)

    Irene D. Alabia

    2016-11-01

    Full Text Available The understanding of the spatio-temporal distributions of the species habitat in the marine environment is central to effectual resource management and conservation. Here, we examined the potential habitat distributions of Japanese common squid (Todarodes pacificus in the Sea of Japan during a four-year period. The seasonal patterns of preferential habitat were inferred from species distribution models, built using squid occurrences detected from night-time visible images and remotely-sensed environmental factors. The predicted squid habitat (i.e., areas with high habitat suitability revealed strong seasonal variability, characterized by a reduction of potential habitat, confined off of the southern part of the basin during the winter–spring period (December–May. Apparent expansion of preferential habitat occurred during summer–autumn months (June–November, concurrent with the formation of highly suitable habitat patches in certain regions of the Sea of Japan. These habitat distribution patterns were in response to changes in oceanographic conditions and synchronous with seasonal migration of squid. Moreover, the most important variables regulating the spatio-temporal patterns of suitable habitat were sea surface temperature, depth, sea surface height anomaly, and eddy kinetic energy. These variables could affect the habitat distributions through their impacts on growth and survival of squid, local nutrient transport, and the availability of favorable spawning and feeding grounds.

  18. Bathymetry of NPS's Virgin Islands Coral Reef National Monument (Inshore), St. John, US Virgin Islands 2005, 1M Grid, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Grid with 1 meter cell size representing the bathymetry of an inshore portion of the NPS's Virgin Islands Coral Reef National Monument,...

  19. Characterization and demonstration results of a SQUID magnetometer system developed for geomagnetic field measurements

    Science.gov (United States)

    Kawai, J.; Miyamoto, M.; Kawabata, M.; Nosé, M.; Haruta, Y.; Uehara, G.

    2017-08-01

    We characterized a low temperature superconducting quantum interference device (SQUID) magnetometer system developed for high-sensitivity geomagnetic field measurement, and demonstrated the detection of weak geomagnetic signals. The SQUID magnetometer system is comprised of three-axis SQUID magnetometers housed in a glass fiber reinforced plastic cryostat, readout electronics with flux locked loop (FLL), a 24-bit data logger with a global positioning system and batteries. The system noise was approximately 0.2 pT √Hz- 1/2 in the 1-50 Hz frequency range. This performance was determined by including the thermal noise and the shielding effect of the copper shield, which covered the SQUID magnetometers to eliminate high-frequency interference. The temperature drift of the system was ˜0.8 pT °C- 1 in an FLL operation. The system operated for a month using 33 l liquid helium. Using this system, we performed the measurements of geomagnetic field in the open-air, far away from the city. The system could detect weak geomagnetic signals such as the Schumann resonance with sixth harmonics, and the ionospheric Alfvén resonance appearing at night, for the north-south and east-west components of the geomagnetic field. We confirm that the system was capable of high-sensitivity measurement of the weak geomagnetic activities.

  20. SQUID-Detected Magnetic Resonance Imaging in MicroteslaFields

    Energy Technology Data Exchange (ETDEWEB)

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2006-08-14

    amplitude in MRI using laser polarized noble gases such as {sup 3}He or {sup 129}Xe (10-12). Hyperpolarized gases were used successfully to image the human lung in fields on the order of several mT (13-15). To overcome the sensitivity loss of Faraday detection at low frequencies, ultrasensitive magnetometers based on the Superconducting QUantum Interference Device (SQUID) (16) are used to detect NMR and MRI signals (17-24). Recently, SQUID-based MRI systems capable of acquiring in vivo images have appeared. For example, in the 10-mT system of Seton et al. (18) signals are coupled to a SQUID via a superconducting tuned circuit, while Clarke and coworkers (22, 25, 26) developed a system at 132 {micro}T with an untuned input circuit coupled to a SQUID. In a quite different approach, atomic magnetometers have been used recently to detect the magnetization (27) and NMR signal (28) of hyperpolarized gases. This technique could potentially be used for low-field MRI in the future. The goal of this review is to summarize the current state-of-the-art of MRI in microtesla fields detected with SQUIDs. The principles of SQUIDs and NMR are briefly reviewed. We show that very narrow NMR linewidths can be achieved in low magnetic fields that are quite inhomogeneous, with illustrative examples from spectroscopy. After describing our ultralow-field MRI system, we present a variety of images. We demonstrate that in microtesla fields the longitudinal relaxation T{sub 1} is much more material dependent than is the case in high fields; this results in a substantial improvement in 'T{sub 1}-weighted contrast imaging'. After outlining the first attempts to combine microtesla NMR with magnetoencephalography (MEG) (29), we conclude with a discussion of future directions.

  1. Trophic relationships between the jumbo squid (Dosidicus gigas and the lightfish (Vinciguerria lucetia in the Humboldt Current System off Peru

    Directory of Open Access Journals (Sweden)

    Rigoberto Rosas-Luis

    2011-04-01

    Full Text Available Acoustic surveys for assessing the biomass and distribution of the jumbo squid (Dosidicus gigas and the lightfish (Vinciguerria lucetia were carried out in the Humboldt Current System of Peru in 2007 and 2008. At the same time, 937 jumbo squid were caught and their stomach contents analyzed. The diet of the jumbo squid was dominated by mesopelagic fish. The first component of their fish diet was V. lucetia and the second component was the myctophid fish Diogenichthys laternatus. Acoustic biomass estimates of these species show that V. lucetia is an important component in aggregative structures in the Humboldt Current System of Peru and its distribution and movements are closely related to the migratory movements of the jumbo squid. The trophic relationship observed between D. gigas and V. lucetia promotes an increase in jumbo squid biomass and, has a positive trophic effect on the ocean ecosystem.

  2. Can understanding squid life-history strategies and recruitment ...

    African Journals Online (AJOL)

    Current views of the links between life-history strategies and recruitment processes in fish are contrasted with the pattern emerging for squid. A general perspective is that the roles of space and time are reversed in the two groups, suggesting that management strategies also should differ. The space/time reversal appears to ...

  3. Verification of the weak equivalence principle of supports and heavy masses using SQUIDs; Ueberpruefung des schwachen Aequivalenzprinzips von Traegern und schwerer Masse mittels Squids

    Energy Technology Data Exchange (ETDEWEB)

    Vodel, W.; Nietzsche, S.; Neubert, R. [Friedrich-Schiller-Universitaet Jena (Germany). Inst. fuer Festkoerperphysik; Dittus, H. [Univ. Bremen (Germany). Zentrum fuer angewandte Raumfahrttechnologie und Mikrogravitation

    2003-07-01

    The weak equivalence principle is one of the fundamental hypotheses of general relativity and one of the key elements of our physical picture of the world, but since Galileo there has been no satisfactory way of verifying it. The new SQUID technology may offer a solution. The contribution presents the experiments of Jena University. Applications are envisaged, e.g., in the STEP space mission of the NASA/ESA. [German] Das Schwache Aequivalenzprinzip ist eine der grundlegenden Hypothesen der Allgemeinen Relativitaetstheorie und damit einer der Grundpfeiler unseres physikalischen Weltbildes. Obwohl es seit den ersten Experimenten von Galileo Galilei am Schiefen Turm zu Pisa im Jahre 1638 bis heute schon zahlreiche und immer praeziser werdende Messungen zur Ueberpruefung der Aequivalenz von schwerer und traeger Masse gegeben hat, ist die strenge Gueltigkeit dieses fundamentalen Prinzips experimentell vergleichsweise unzureichend bestimmt. Neuere Methoden, wie der Einsatz SQUID-basierter Messtechnik und die Durchfuehrung von Experimenten auf Satelliten, lassen Verbesserungen schon in naher Zukunft erwarten, so dass theoretische Ueberlegungen zur Vereinigung aller uns bekannten physikalischen Wechselwirkungen, die eine Verletzung des Schwachen Aequivalenzprinzips voraussagen, experimentell eingegrenzt werden koennten. Der Beitrag gibt einen Ueberblick ueber die an der Universitaet Jena entwickelte SQUID-basierte Messtechnik zum Test des Aequivalenzprinzips und fasst die bisher bei Freifallversuchen am Fallturm Bremen erzielten experimentellen Ergebnisse zusammen. Ein Ausblick auf die geplante Raumfahrtmission STEP der NASA/ESA zum Praezisionstest des Schwachen Aequivalenzprinzips schliesst den Beitrag ab. (orig.)

  4. Disease outbreaks, bleaching and a cyclone drive changes in coral assemblages on an inshore reef of the Great Barrier Reef

    Science.gov (United States)

    Haapkylä, J.; Melbourne-Thomas, J.; Flavell, M.; Willis, B. L.

    2013-09-01

    Coral disease is a major threat to the resilience of coral reefs; thus, understanding linkages between disease outbreaks and disturbances predicted to increase with climate change is becoming increasingly important. Coral disease surveys conducted twice yearly between 2008 and 2011 at a turbid inshore reef in the central Great Barrier Reef spanned two disturbance events, a coral bleaching event in 2009 and a severe cyclone (cyclone `Yasi') in 2011. Surveys of coral cover, community structure and disease prevalence throughout this 4-yr study provide a unique opportunity to explore cumulative impacts of disturbance events and disease for inshore coral assemblages. The principal coral disease at the study site was atramentous necrosis (AtN), and it primarily affected the key inshore, reef-building coral Montipora aequituberculata. Other diseases detected were growth anomalies, white syndrome and brown band syndrome. Diseases affected eight coral genera, although Montipora was, by far, the genus mostly affected. The prevalence of AtN followed a clear seasonal pattern, with disease outbreaks occurring only in wet seasons. Mean prevalence of AtN on Montipora spp. (63.8 % ± 3.03) was three- to tenfold greater in the wet season of 2009, which coincided with the 2009 bleaching event, than in other years. Persistent wet season outbreaks of AtN combined with the impacts of bleaching and cyclone events resulted in a 50-80 % proportional decline in total coral cover. The greatest losses of branching and tabular acroporids occurred following the low-salinity-induced bleaching event of 2009, and the greatest losses of laminar montiporids occurred following AtN outbreaks in 2009 and in 2011 following cyclone Yasi. The shift to a less diverse coral assemblage and the concomitant loss of structural complexity are likely to have long-term consequences for associated vertebrate and invertebrate communities on Magnetic Island reefs.

  5. Greatly improved cache update times for conditions data with Frontier/Squid

    International Nuclear Information System (INIS)

    Dykstra, Dave; Lueking, Lee

    2009-01-01

    The CMS detector project loads copies of conditions data to over 100,000 computer cores worldwide by using a software subsystem called Frontier. This subsystem translates database queries into HTTP, looks up the results in a central database at CERN, and caches the results in an industry-standard HTTP proxy/caching server called Squid. One of the most challenging aspects of any cache system is coherency, that is, ensuring that changes made to the underlying data get propagated out to all clients in a timely manner. Recently, the Frontier system was enhanced to drastically reduce the time for changes to be propagated everywhere without heavily loading servers. The propagation time is now as low as 15 minutes for some kinds of data and no more than 60 minutes for the rest of the data. This was accomplished by taking advantage of an HTTP and Squid feature called If-Modified-Since. In order to use this feature, the Frontier server sends a Last-Modified timestamp, but since modification times are not normally tracked by Oracle databases, a PL/SQL program was developed to track the modification times of database tables. We discuss the details of this caching scheme and the obstacles overcome including database and Squid bugs.

  6. Greatly improved cache update times for conditions data with Frontier/Squid

    Energy Technology Data Exchange (ETDEWEB)

    Dykstra, Dave; Lueking, Lee, E-mail: dwd@fnal.go [Computing Division, Fermilab, Batavia, IL (United States)

    2010-04-01

    The CMS detector project loads copies of conditions data to over 100,000 computer cores worldwide by using a software subsystem called Frontier. This subsystem translates database queries into HTTP, looks up the results in a central database at CERN, and caches the results in an industry-standard HTTP proxy/caching server called Squid. One of the most challenging aspects of any cache system is coherency, that is, ensuring that changes made to the underlying data get propagated out to all clients in a timely manner. Recently, the Frontier system was enhanced to drastically reduce the time for changes to be propagated everywhere without heavily loading servers. The propagation time is now as low as 15 minutes for some kinds of data and no more than 60 minutes for the rest of the data. This was accomplished by taking advantage of an HTTP and Squid feature called If-Modified-Since. In order to use this feature, the Frontier server sends a Last-Modified timestamp, but since modification times are not normally tracked by Oracle databases, a PL/SQL program was developed to track the modification times of database tables. We discuss the details of this caching scheme and the obstacles overcome including database and Squid bugs.

  7. Reduction of environmental MHz noise for SQUID application

    Energy Technology Data Exchange (ETDEWEB)

    Araya, T. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: araya@sup.ee.es.osaka-u.ac.jp; Kitamura, Y. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Kamishiro, M. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Sakuta, K. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Itozaki, H. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: itozaki@ee.es.osaka-u.ac.jp

    2006-10-01

    It is important to remove large environmental noise in measurement using SQUIDs without magnetic shielding. Active noise control (ANC) is an effective method to remove the environmental noise. The environmental noise has been reduced by the ANC system in the radio frequency region around MHz. The anti-phase waves of the environmental noise should be generated by this system. The ANC system including the phase and amplitude control circuit was developed to make the anti-phase waves in the MHz region. In this paper, sinusoidal waves with a MHz frequency were used as the environmental noise. When a coil antenna was used for a receiver antenna, this ANC system suppressed these sinusoidal waves to the white noise level about 40 dB. When we used a SQUID as a receiver antenna, we also cancelled sinusoidal waves to the white noise level by this system. This shows that the ANC system is useful to reduce an environmental noise when this ANC system is developed to cancel multi-frequency noise.

  8. Reduction of environmental MHz noise for SQUID application

    International Nuclear Information System (INIS)

    Araya, T.; Kitamura, Y.; Kamishiro, M.; Sakuta, K.; Itozaki, H.

    2006-01-01

    It is important to remove large environmental noise in measurement using SQUIDs without magnetic shielding. Active noise control (ANC) is an effective method to remove the environmental noise. The environmental noise has been reduced by the ANC system in the radio frequency region around MHz. The anti-phase waves of the environmental noise should be generated by this system. The ANC system including the phase and amplitude control circuit was developed to make the anti-phase waves in the MHz region. In this paper, sinusoidal waves with a MHz frequency were used as the environmental noise. When a coil antenna was used for a receiver antenna, this ANC system suppressed these sinusoidal waves to the white noise level about 40 dB. When we used a SQUID as a receiver antenna, we also cancelled sinusoidal waves to the white noise level by this system. This shows that the ANC system is useful to reduce an environmental noise when this ANC system is developed to cancel multi-frequency noise

  9. Preparation and characterisation of irradiated crab chitosan and New Zealand Arrow squid pen chitosan

    International Nuclear Information System (INIS)

    Shavandi, Amin; Bekhit, Adnan A.; Bekhit, Alaa El-Din A.; Sun, Zhifa; Ali, M. Azam

    2015-01-01

    The properties of chitosan from Arrow squid (Nototodarus sloanii) pen (CHS) and commercial crab shell (CHC) were investigated using FTIR, DSC, SEM and XRD before and after irradiation at the dose of 28 kGy in the presence or absence of 5% water. Also, the viscosity, deacetylation degree, water and oil holding capacities, colour and antimicrobial activities of the chitosan samples were determined. Irradiation decreased (P < 0.05) the viscosity of CHC from 0.21 to 0.03 Pa s and of CHS from 1.71 to 0.23 Pa s. The inclusion of water had no effect on the viscosity of irradiated chitosan. Irradiation did not affect the degree of deacetylation of CHC, but increased the deacetylation degree of CHS from 72.78 to 82.29% in samples with 5% water. Water and oil holding capacities of CHS (1197.30% and 873.3%, respectively) were higher (P < 0.05) than those found in CHC (340.70% and 264.40%, respectively). The water and oil holding capacities were decreased for both types of chitosan irradiation, but were not affected by the addition of water. Squid pen chitosan was whiter in colour (White Index = 90.06%) compared to CHC (White Index = 83.70%). Generally, the CHC samples (control and irradiated) exhibited better antibacterial activity compared to CHS, but the opposite was observed with antifungal activity. - Highlights: • Chitosan prepared from Arrow squid pens (Nototodarus sloanii). • Chitosan samples were gamma irradiated at 28 kGy. • Squid pen chitosan showed high fat and water uptake capacities compared to crab shell chitosan. • Gamma irradiation enhanced the DDA of squid pen chitosan but not crab shell chitosan.

  10. Design and Performance of the Multiplexed SQUID/TES Array at Ninety Gigahertz

    Science.gov (United States)

    Stanchfield, Sara; Ade, Peter; Aguirre, James; Brevik, Justus A.; Cho, Hsiao-Mei; Datta, Rahul; Devlin, Mark; Dicker, Simon R.; Dober, Bradley; Duff, Shannon M.; Egan, Dennis; Ford, Pam; Hilton, Gene; Hubmayr, Johannes; Irwin, Kent; Knowles, Kenda; Marganian, Paul; Mason, Brian Scott; Mates, John A. B.; McMahon, Jeff; Mello, Melinda; Mroczkowski, Tony; Romero, Charles; Sievers, Jonathon; Tucker, Carole; Vale, Leila R.; Vissers, Michael; White, Steven; Whitehead, Mark; Ullom, Joel; Young, Alexander

    2018-01-01

    We present the array performance and astronomical images from early science results from MUSTANG-2, a 90 GHz feedhorn-coupled, microwave SQUID-multiplexed TES bolometer array operating on the Robert C. Byrd Green Bank Telescope (GBT). MUSTANG-2 was installed on the GBT on December 2, 2016 and immediately began commissioning efforts, followed by science observations, which are expected to conclude June 2017. The feedhorn and waveguide-probe-coupled detector technology is a mature technology, which has been used on instrument including the South Pole Telescope, the Atacama Cosmology Telescope, and the Atacama B-mode Search telescope. The microwave SQUID readout system developed for MUSTANG-2 currently reads out 66 detectors with a single coaxial cable and will eventually allow thousands of detectors to be multiplexed. This microwave SQUID multiplexer combines the proven abilities of millimeterwave TES detectors with the multiplexing capabilities of KIDs with no degradation in noise performance of the detectors. Each multiplexing device is read out using warm electronics consisting of a commercially available ROACH board, a DAC/ADC card, and an Intermediate Frequency mixer circuit. The hardware was originally developed by the UC Berkeley Collaboration for Astronomy Signal Processing and Electronic Research (CASPER) group, whose primary goal is to develop scalable FPGA-based hardware with the flexibility to be used in a wide range of radio signal processing applications. MUSTANG-2 is the first on-sky instrument to use microwave SQUID multiplexing and is available as a shared-risk/PI instrument on the GBT. In MUSTANG-2's first season 7 separate proposals were awarded a total of 230 hours of telescope time.

  11. Optimization of a digital SQUID magnetometer in terms of noise and distortion

    International Nuclear Information System (INIS)

    Haverkamp, I; Toepfer, H; Wetzstein, O; Kunert, J; Stolz, R; Meyer, H-G; Ortlepp, T

    2012-01-01

    The digital SQUID magnetometer takes advantage of flux quantization in a superconducting loop in order to measure magnetic fields. The core element of the digital SQUID is a Josephson comparator with a superconducting antenna loop attached to one of its junctions. Evaluation of the circuit from the system’s point of view requires an analysis in the frequency domain. In order to obtain a high-resolution fast Fourier transform, large datasets are necessary which are difficult to generate with transient simulation tools. In this work we derive a behavioural model for the digital SQUID in order to overcome restrictions imposed by transient simulation. By means of this model the influence of the comparator grey zone and the input loop inductance on the system performance was analysed. In order to assess the system, evaluation criteria based on the power spectral density were applied, which are commonly used for characterization of semiconductor analogue to digital converters. As a result of this study, design guidelines for an optimum antenna inductance depending on the comparator grey zone are derived, allowing us to achieve an optimum system performance in terms of noise and distortion. (paper)

  12. SQUID-based Nondestructive Testing Instrument of Dished Niobium Sheets for SRF Cavities

    International Nuclear Information System (INIS)

    Q. S. Shu; I. Ben-Zvi; G. Cheng; I. M. Phipps; J. T. Susta; P. Kneisel; G. Myneni; J. Mast; R. Selim

    2007-01-01

    Currently available technology can only inspect flat sheets and allow the elimination of defective flat sheets before the expensive forming and machining of the SRF cavity half-cells, but it does not eliminate the problem of remaining or uncovered surface impurities after partial chemical etching of the half-cells, nor does it detect any defects that may have been added during the fabrication of the half-cells. AMAC has developed a SQUID scanning system based on eddy current technique that allows the scanning of curved Nb samples that are welded to make superconducting RF cavity half-cells. AMAC SQUID scanning system successfully located the defects (Ta macro particles about 100 mm diameter) in a flat Nb sample (top side) and was able to also locate the defects in a cylindrical surface sample (top side). It is more significant that the system successfully located the defects on the backside of the flat sample and curved sample or 3-mm from the top surface. The 3-D SQUID-based Nondestructive instrument will be further optimized and improved in making SRF cavities and allow inspection and detection during cavity manufacturing for achieving highest accelerating fields

  13. Transfer of 60Co from midwater squid to sperm whales

    International Nuclear Information System (INIS)

    Umezu, Takeshi; Minamisako, Yoko; Ebihara, Hiroshi; Watanabe, Hiroshi.

    1984-01-01

    Sperm whales are notable squid-eaters. They feed mainly on medium to large-sized cephalopods at midwater levels and defecate near the surface. This suggests the existence of an upward transport of 60 Co by sperm whales from the mesopelagic zone (150-1,200m). To elucidate this squid-whale route for this artificial radionuclide, 60 Co content was determined in squid and in predator whales captured by commercial whaling. In the Cephalopoda livers 60 Co levels of 30-500 mBq kg -1 wet were found and in the viscera of Odontoceti (toothed whales) 15-40 mBq kg -1 wet. About 0.3% of 60 Co ingested was estimated to be retained in a 23-year-old male sperm whale. In the livers of Bryde's whales, 60 Co levels of 40-80 mBq kg -1 wet were detected, but not in euphausiids and sardines, their possible prey. The level of Co in sperm whales was nearly the same as in Bryde's whales. Specific radioactivity 60 Co/ 59 Co in mBq μg -1 was several times higher in sperm whale (1.1-1.6) than in cephalopods (0.19-0.77). Eating prey with a high content of 60 Co in the 1960's may have contributed to the present body burden in sperm whales with a long-life span. However, the origin of 60 Co in Bryde's whales is unknown. (author)

  14. Extreme plasticity in life-history strategy allows a migratory predator (jumbo squid) to cope with a changing climate.

    Science.gov (United States)

    Hoving, Henk-Jan T; Gilly, William F; Markaida, Unai; Benoit-Bird, Kelly J; -Brown, Zachary W; Daniel, Patrick; Field, John C; Parassenti, Liz; Liu, Bilin; Campos, Bernardita

    2013-07-01

    Dosidicus gigas (jumbo or Humboldt squid) is a semelparous, major predator of the eastern Pacific that is ecologically and commercially important. In the Gulf of California, these animals mature at large size (>55 cm mantle length) in 1-1.5 years and have supported a major commercial fishery in the Guaymas Basin during the last 20 years. An El Niño event in 2009-2010, was accompanied by a collapse of this fishery, and squid in the region showed major changes in the distribution and life-history strategy. Large squid abandoned seasonal coastal-shelf habitats in 2010 and instead were found in the Salsipuedes Basin to the north, an area buffered from the effects of El Niño by tidal upwelling and a well-mixed water column. The commercial fishery also relocated to this region. Although large squid were not found in the Guaymas Basin from 2010 to 2012, small squid were abundant and matured at an unusually small mantle-length (adapt to and cope with El Niño. This ability is likely to be an important factor in conjunction with longerterm climate-change and the potential ecological impacts of this invasive predator on marine ecosystems. © 2013 Blackwell Publishing Ltd.

  15. Research on Intelligent Control System of DC SQUID Magnetometer Parameters for Multi-channel System

    Science.gov (United States)

    Chen, Hua; Yang, Kang; Lu, Li; Kong, Xiangyan; Wang, Hai; Wu, Jun; Wang, Yongliang

    2018-03-01

    In a multi-channel SQUID measurement system, adjusting device parameters to optimal condition for all channels is time-consuming. In this paper, an intelligent control system is presented to determine the optimal working point of devices which is automatic and more efficient comparing to the manual one. An optimal working point searching algorithm is introduced as the core component of the control system. In this algorithm, the bias voltage V_bias is step scanned to obtain the maximal value of the peak-to-peak current value I_pp of the SQUID magnetometer modulation curve. We choose this point as the optimal one. Using the above control system, more than 30 weakly damped SQUID magnetometers with area of 5 × 5 mm^2 or 10 × 10 mm^2 are adjusted and a 36-channel magnetocardiography system perfectly worked in a magnetically shielded room. The average white flux noise is 15 μΦ_0/Hz^{1/2}.

  16. Development of non-destructive evaluation system using an HTS-SQUID gradiometer for magnetized materials

    Science.gov (United States)

    Kawano, J.; Tsukamoto, A.; Adachi, S.; Oshikubo, Y.; Hato, T.; Tanabe, K.; Okamura, T.

    We have developed a new eddy-current non-destructive evaluation (NDE) system using an HTS SQUID gradiometer with the aim of applying it to practical materials with magnetization. The new NDE system employs a LN2-cooled external Cu pickup coil and an HTS SQUID chip placed in a magnetic shield made of HTS material. The HTS SQUID chip consists of an HTS planar gradiometer manufactured by using a ramp-edge junction technology and a multi-turn HTS thin film input coil coupled with the flip-chip configuration. The first-order coaxial gradiometric Cu pickup coil with a diameter of 16 mm and the baseline of 5.6 mm was used in the present NDE experiments. By using this NDE system, we could observe defect-induced magnetic signals without an appreciable influence of magnetization up to 10 mT. We also examined the ability of detecting deep-lying defects and compared with the results obtained using our previous NDE system.

  17. Effect of electron beam on the microbiological and sensory characteristics of squid jeotkal and its ingredients

    International Nuclear Information System (INIS)

    Liu Xiande; Piao Linghua

    2012-01-01

    A seasoned squid Jeotkal, Koran traditional fermented seafood, and its ingredients for manufacturing, including red hot pepper powder and ground garlic were irradiated by 0, 0.5, 1, 2 and 5 kGy electron beam and stored at 4 ℃ for 4 weeks to determine the changes of microorganisms and sensory characteristics. The initial contamination of squid Jeotkal such as total aerobic bacteria, yeast and mold, and coliform bacterial were at the levels of 2.88, 3.04 and 4.20 logCFU/g, respectively. However, 5 kGy electron beam irradiation reduced the total aerobic bacteria about 1 logCFU/g. Yeast and mold and coliform bacterial were reduced 1 ∼ 2 logCFU/g after 2 kGy irradiation and reached to undetected level when the sample was irradiated at 5 kGy and following storage at 4 ℃ for 4 weeks. Sensory characteristics showed that 5 kGy electron beam irradiation did not adversely affect overall acceptability of squid Jeotkal and its ingredients during 4 ℃ storage. Therefore, electron beam irradiation is one of the possible methods to improve storage stability of seasoned squid Jeotkal. (authors)

  18. Ultra-Low Field SQUID-NMR using LN2 Cooled Cu Polarizing Field coil

    Science.gov (United States)

    Demachi, K.; Kawagoe, S.; Ariyoshi, S.; Tanaka, S.

    2017-07-01

    We are developing an Ultra-Low Field (ULF) Magnetic Resonance Imaging (MRI) system using a High-Temperature Superconductor superconducting quantum interference device (HTS rf-SQUID) for food inspection. The advantages of the ULF-NMR (Nuclear Magnetic Resonance) / MRI as compared with a conventional high field MRI are that they are compact and of low cost. In this study, we developed a ULF SQUID-NMR system using a polarizing coil to measure fat of which relaxation time T1 is shorter. The handmade polarizing coil was cooled by liquid nitrogen to reduce the resistance and accordingly increase the allowable current. The measured decay time of the polarizing field was 40 ms. The measurement system consisted of the liquid nitrogen cooled polarizing coil, a SQUID, a Cu wound flux transformer, a measurement field coil for the field of 47 μT, and an AC pulse coil for a 90°pulse field. The NMR measurements were performed in a magnetically shielded room to reduce the environmental magnetic field. The size of the sample was ϕ35 mm × L80 mm. After applying a polarizing field and a 90°pulse, an NMR signal was detected by the SQUID through the flux transformer. As a result, the NMR spectra of fat samples were obtained at 2.0 kHz corresponding to the measurement field Bm of 47 μT. The T1 relaxation time of the mineral oil measured in Bm was 45 ms. These results suggested that the ULF-NMR/MRI system has potential for food inspection.

  19. Y1Ba2Cu3O(7-delta) thin film dc SQUIDs (superconducting quantum interference device)

    Science.gov (United States)

    Racah, Daniel

    1991-03-01

    Direct current superconducting quantum interferometers (SQUIDs) based on HTSC thin films have been measured and characterized. The thin films used were of different quality: (1) Granular films on Sapphire substrates, prepared either by e-gun evaporation, by laser ablation or by MOCVD (metal oxide chemical vapor deposition), (2) Epitaxial films on MgO substrates. Modulations of the voltage on the SQUIDs as a function of the applied flux have been observed in a wide range of temperatures. The nature of the modulation was found to be strongly dependent on the morphology of the film and on its critical current. The SQUIDs based on granular films were relatively noisy, hysteretic and with a complicated V-phi shape. Those devices based on low quality (lowIc) granular films could be measured only at low temperatures (much lower than 77 K). While those of higher quality (granular films with high Ic) could be measured near to the superconductive transition. The SQUID based on high quality epitaxial film was measured near Tc and showed an anomalous, time dependent behavior.

  20. Electronics for a Next-Generation SQUID-Based Time-Domain Multiplexing System

    International Nuclear Information System (INIS)

    Reintsema, C. D.; Doriese, W. R.; Hilton, G. C.; Irwin, K. D.; Krinsky, J. W.; Adams, J. S.; Baker, R.; Bandler, S. R.; Kelly, R. L.; Kilbourne, C. A.; Porter, F. S.; Figueroa-Feliciano, E.; Wikus, P.

    2009-01-01

    A decade has elapsed since the design, development and realization of a SQUID-based time-division multiplexer at NIST. During this time the system has been used extensively for low-temperature-detector-array measurements. Concurrently, there have been substantial advancements both in detector array and commercial electronic component technology. The relevance and applicability of the technology has blossomed as well, often accompanied by more demanding measurement requirements. These factors have motivated a complete redesign of the NIST room-temperature read-out electronics. The redesign has leveraged advancements in component technology to achieve new capabilities better suited to the SQUID multiplexers and detector arrays being realized today. As examples of specific performance enhancements, the overall system bandwidth has been increased by a factor of four (a row switching rate of 6.24 MHz), the compactness has been increased by over a factor of two (a higher number of detector columns and rows per circuit board), and there are two high speed outputs per column (allowing fast switching of SQUID offsets in addition to digital feedback). The system architecture, design implementations, and performance advantages of the new system will be discussed. As an application example, the science chain flight electronics for the Micro-X High Resolution Microcalorimeter X-ray Imaging Rocket will be described as both a motivation for, and a direct implementation of the new system.

  1. Solid state characterization of α-chitin from Vanessa cardui Linnaeus wings

    International Nuclear Information System (INIS)

    Schiffman, Jessica D.; Schauer, Caroline L.

    2009-01-01

    Material properties of the painted lady butterfly, Vanessa cardui Linnaeus were investigated using typical material science techniques. The examined butterflies were raised and hatched from the larvae stage and their chemical and crystalline structure evaluated and compared to that of crab shell (α-chitin) and squid pens from Notodarus sloanii and Loligo pealei (β-chitin). Fourier transmission infrared spectroscopy (FTIR) and X-ray diffraction (XRD) revealed that the painted lady butterflies are composed of α-chitin. Additionally, macro- and microstructure characterization of the chitins was conducted utilizing digital photography and field emission scanning electron microscopy (FESEM). This work demonstrates that common characterization techniques combined with simple sample preparation of biological materials can yield successful material characterization, which could aide the fabrication of biomimetic materials.

  2. Solid state characterization of {alpha}-chitin from Vanessa cardui Linnaeus wings

    Energy Technology Data Exchange (ETDEWEB)

    Schiffman, Jessica D. [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA (United States); Schauer, Caroline L., E-mail: cschauer@coe.drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA (United States)

    2009-05-05

    Material properties of the painted lady butterfly, Vanessa cardui Linnaeus were investigated using typical material science techniques. The examined butterflies were raised and hatched from the larvae stage and their chemical and crystalline structure evaluated and compared to that of crab shell ({alpha}-chitin) and squid pens from Notodarus sloanii and Loligo pealei ({beta}-chitin). Fourier transmission infrared spectroscopy (FTIR) and X-ray diffraction (XRD) revealed that the painted lady butterflies are composed of {alpha}-chitin. Additionally, macro- and microstructure characterization of the chitins was conducted utilizing digital photography and field emission scanning electron microscopy (FESEM). This work demonstrates that common characterization techniques combined with simple sample preparation of biological materials can yield successful material characterization, which could aide the fabrication of biomimetic materials.

  3. SQUID readout multiplexers for transition-edge sensor arrays

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Adrian T. [Physics Department, University of California, Berkeley, CA 94720 (United States) and Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)]. E-mail: atl@physics.berkeley.edu

    2006-04-15

    Two classes of SQUID multiplexer are being developed for large arrays of cryogenic sensors, distinguished by their operation in either the time domain or frequency domain. Several systems optimized for use with Transition-Edge Sensors (TES) are reaching a high level of maturity, and will be deployed on funded astrophysics experiments in the next several years. A useful technical figure of merit is the product of the number of detectors multplexed multipled by the bandwidth of the detectors, which can be termed the 'total signal bandwidth' of a multiplexer system. This figure of merit is comparable within a factor of two for the mature systems. Several new concepts for increasing the total bandwidth are being developed in the broad class of frequency domain multiplexers. Another notable area of progress is in the level of integration of muliplexer and detector array. The time domain system for SCUBA-II is a sophisticated bump-bonded sandwich structure, and the Jena/MPI group is integrating detectors and a time domain multiplexer on one substrate. Finally, the Kinetic Inductance Detectors (KID)/HEMT (non-SQUID) detector/multiplexer system, will be discussed briefly.

  4. 76 FR 3044 - Fisheries of the Exclusive Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the...

    Science.gov (United States)

    2011-01-19

    ..., Squid, and Octopus in the Gulf of Alaska AGENCY: National Marine Fisheries Service (NMFS), National... prohibiting directed fishing for sculpins, sharks, squid, and octopus in the Gulf of Alaska (GOA). This action..., and octopus in the GOA. DATES: Effective 1200 hrs, Alaska local time (A.l.t.), January 13, 2011...

  5. SQUID developments for the gravitational wave antenna MiniGRAIL

    NARCIS (Netherlands)

    Pleikies, J.; Usenko, O.; Kuit, K.H.; Flokstra, Jakob; de Waard, A.; de Waard, A.; Frossati, G.

    2007-01-01

    We designed two different sensor SQUIDs for the readout of the resonant mass gravitational wave detector MiniGRAIL. Both designs have integrated input inductors in the order of 1.5 muH and are planned for operation in the mK temperature range. Cooling fins were added to the shunt resistors. The

  6. High-resolution imaging of magnetic fields using scanning superconducting quantum interference device (SQUID) microscopy

    Science.gov (United States)

    Fong de Los Santos, Luis E.

    Development of a scanning superconducting quantum interference device (SQUID) microscope system with interchangeable sensor configurations for imaging magnetic fields of room-temperature (RT) samples with sub-millimeter resolution. The low-critical-temperature (Tc) niobium-based monolithic SQUID sensor is mounted in the tip of a sapphire rod and thermally anchored to the cryostat helium reservoir. A 25 mum sapphire window separates the vacuum space from the RT sample. A positioning mechanism allows adjusting the sample-to-sensor spacing from the top of the Dewar. I have achieved a sensor-to-sample spacing of 100 mum, which could be maintained for periods of up to 4 weeks. Different SQUID sensor configurations are necessary to achieve the best combination of spatial resolution and field sensitivity for a given magnetic source. For imaging thin sections of geological samples, I used a custom-designed monolithic low-Tc niobium bare SQUID sensor, with an effective diameter of 80 mum, and achieved a field sensitivity of 1.5 pT/Hz1/2 and a magnetic moment sensitivity of 5.4 x 10-18 Am2/Hz1/2 at a sensor-to-sample spacing of 100 mum in the white noise region for frequencies above 100 Hz. Imaging action currents in cardiac tissue requires higher field sensitivity, which can only be achieved by compromising spatial resolution. I developed a monolithic low-Tc niobium multiloop SQUID sensor, with sensor sizes ranging from 250 mum to 1 mm, and achieved sensitivities of 480 - 180 fT/Hz1/2 in the white noise region for frequencies above 100 Hz, respectively. For all sensor configurations, the spatial resolution was comparable to the effective diameter and limited by the sensor-to-sample spacing. Spatial registration allowed us to compare high-resolution images of magnetic fields associated with action currents and optical recordings of transmembrane potentials to study the bidomain nature of cardiac tissue or to match petrography to magnetic field maps in thin sections of

  7. SQUID Based Cryogenic Current Comparator for Measurements of the Dark Current of Superconducting Cavities

    CERN Document Server

    Vodel, W; Neubert, R; Nietzsche, S

    2005-01-01

    This contribution presents a LTS-SQUID based Cryogenic Current Comparator (CCC) for detecting dark currents, generated e.g. by superconducting cavities for the upcoming X-FEL project at DESY. To achieve the maximum possible energy the gradients of the superconducting RF cavities should be pushed close to the physical limit of 50 MV/m. The measurement of the undesired field emission of electrons (the so-called dark current) in correlation with the gradient will give a proper value to compare and classify the cavities. The main component of the CCC is a high performance LTS-DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the extracted dark current. For this reason the input coil of the SQUID is connected across a special designed toroidal niobium pick-up coil (inner diameter: about 100 mm) for the passing electron beam. A noise limited current resolution of nearly 2 pA/√(Hz) with a measurement bandwidth of up to 70 kHz was achieved without the pick-up coil. Now, ...

  8. Growth of juvenile shrimp Metapenaeus monoceros fed with squid and mussel

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Nair, S.R.S.; Krishnakumari, L.

    Small juveniles of both sexes and females of large juveniles of Metapenaeus monoceros attained faster growth with squid diet. Males of large juveniles registered better growth with mussel diet. No significant difference was observed in moult weights...

  9. Emulsifying and gelling properties of weakfish myofibrillar proteins as affected by squid mantle myofibrillar proteins in a model system

    Directory of Open Access Journals (Sweden)

    Daniela Mariel Suarez

    2014-03-01

    Full Text Available The aim of the present work was to investigate the physicochemical, biochemical and functional characteristics of both the myofibrils (MF and actomyosin (AM of squid mantle (Illex argentinus and weakfish (Cynoscion guatucupa muscles, and evaluate the influence of the addition of myofibrilar proteins from the squid mantle on the physicochemical and functional properties of those of the weakfish. After extraction, purification and characterization of the MF and AM of both species, emulsions of each protein fraction from each muscle were formulated. Mixtures of the MF or AM of both species were also analyzed. The emulsifying properties were monitoring using the Emulsifying Activity Index (EAI and Emulsion Stability (ES. In addition, gel pastes were formulated from the squid mantle, weakfish muscle and the mixture of both species, and the following functional properties of the gels assessed: water holding capacity, colour, textural profile analysis (TPA (hardness, elasticity, cohesiveness, gumminess and gel strength. The EAI values of emulsions formulated with the MF of the mantle were significantly (p<0.05 higher than those formulated from those of weakfish. The incorporation of squid MF in the mixture increased the EAI values. Conversely, the highest ES values were obtained with weakfish MF, and the incorporation of MF weakfish in the mixture increased the ES values. Similar EAI and ES behaviours were observed for the AM of the corresponding species. Irrespective of the thermal treatment, the gel strength of the gelled paste of squid muscle was significantly (p<0.05 lower than that of weakfish muscle and of those obtained with the different mixtures. The behaviours of the expressible moisture (EM from the gelled pastes were similar to those of gel strength. Irrespective of the thermal treatment, the pastes formulated with a high weakfish: mantle ratio showed less water loss. The gelled pastes of squid mantle showed the highest values for whiteness

  10. A Decision Mixture Model-Based Method for Inshore Ship Detection Using High-Resolution Remote Sensing Images.

    Science.gov (United States)

    Bi, Fukun; Chen, Jing; Zhuang, Yin; Bian, Mingming; Zhang, Qingjun

    2017-06-22

    With the rapid development of optical remote sensing satellites, ship detection and identification based on large-scale remote sensing images has become a significant maritime research topic. Compared with traditional ocean-going vessel detection, inshore ship detection has received increasing attention in harbor dynamic surveillance and maritime management. However, because the harbor environment is complex, gray information and texture features between docked ships and their connected dock regions are indistinguishable, most of the popular detection methods are limited by their calculation efficiency and detection accuracy. In this paper, a novel hierarchical method that combines an efficient candidate scanning strategy and an accurate candidate identification mixture model is presented for inshore ship detection in complex harbor areas. First, in the candidate region extraction phase, an omnidirectional intersected two-dimension scanning (OITDS) strategy is designed to rapidly extract candidate regions from the land-water segmented images. In the candidate region identification phase, a decision mixture model (DMM) is proposed to identify real ships from candidate objects. Specifically, to improve the robustness regarding the diversity of ships, a deformable part model (DPM) was employed to train a key part sub-model and a whole ship sub-model. Furthermore, to improve the identification accuracy, a surrounding correlation context sub-model is built. Finally, to increase the accuracy of candidate region identification, these three sub-models are integrated into the proposed DMM. Experiments were performed on numerous large-scale harbor remote sensing images, and the results showed that the proposed method has high detection accuracy and rapid computational efficiency.

  11. Long-term temporal and spatial changes in the richness and relative abundance of the inshore fish community of the British North Sea Coast

    Science.gov (United States)

    Henderson, Peter A.

    2017-09-01

    Changes in temporal and spatial composition of the British inshore North Sea fish community are reviewed. Sampling from the cooling water filter screens of power stations bordering the North Sea commenced in the early 1960s. To date, a total of 112 marine fish species have been recorded, a high proportion of the total inshore fish species complement of shallow North Sea British waters. The unrecorded top predators, such as large sharks, swordfish and tuna are not regularly observed in waters fish diversity and abundance in large industrialised estuaries such as the Thames and the Firth of Forth. Linked to spawning and nursery habitat gain, smelt, Osmerus eperlangus, and bass, Dicentrarchus labrax, have greatly increased in abundance. There is no evidence for a decline in species richness since the 1970s. However, elasmobranch species number has declined while two species Raja clavata and Scyliorhinus canicula have remained abundant and one, Mustelus asterias, has increased in abundance. It is argued that overexploitation and habitat destruction remain, as they have been for the last 300 years, the most serious threats to the health of North Sea inshore fish communities. There are no clear signs that climate change is causing species loss, although it may be influencing relative species abundance as species at the southern edge of their range such as the viviparous blenny, Zoarces viviparous, have declined in the southern British North Sea. Power station water temperature records do not show a warming trend, in some estuarine locations temperature has declined with reduced thermal pollution; the temperature record cannot explain the observed major changes in fish relative abundance observed since the 1970s.

  12. A contribution to the biology of the ommastrephid squid Martialia ...

    African Journals Online (AJOL)

    Updated knowledge on the distribution and biology of the ommastrephid squid Martialia hyadesi in the South-West Atlantic Ocean is presented. Although the species has an Antarctic circumpolar distribution, its most frequent area of appearance is in the South-West Atlantic, where commercial catches have been made.

  13. The magnapinnidae, a newly discovered family of oceanic Squid ...

    African Journals Online (AJOL)

    A peculiar squid paralarva from Hawaiian waters was described by Young (1991, Bull. mar. Sci. 49(1–2): 162–185), but it could not be assigned to any known family. Two larger juvenile specimens have now been obtained, one collected near the surface in the eastern Pacific Ocean and the other rehydrated from a dried ...

  14. Effect of single- and two-cycle high hydrostatic pressure treatments on water properties, physicochemical and microbial qualities of minimally processed squids (todarodes pacificus).

    Science.gov (United States)

    Zhang, Yifeng; Jiao, Shunshan; Lian, Zixuan; Deng, Yun; Zhao, Yanyun

    2015-05-01

    This study investigated the effect of single- and two-cycle high hydrostatic pressure (HHP) treatments on water properties, physicochemical, and microbial qualities of squids (Todarodes pacificus) during 4 °C storage for up to 10 d. Single-cycle treatments were applied at 200, 400, or 600 MPa for 20 min (S-200, S-400, and S-600), and two-cycle treatments consisted of two 10 min cycles at 200, 400, or 600 MPa, respectively (T-200, T-400, and T-600). HHP-treated samples had higher (P pressure level caused no significant difference in water state of squids. The two-cycle HHP treatment was more effective in controlling total volatile basic nitrogen, pH, and total plate counts (TPC) of squids during storage, in which TPC of S-600 and T-600 was 2.9 and 1.8 log CFU/g at 10 d, respectively, compared with 7.5 log CFU/g in control. HHP treatments delayed browning discoloration of the squids during storage, and the higher pressure level and two-cycle HHP were more effective. Water properties highly corresponded with color and texture indices of squids. This study demonstrated that the two-cycle HHP treatment was more effective in controlling microbial growth and quality deterioration while having similar impact on the physicochemical and water properties of squids in comparison with the single-cycle treatment, thus more desirable for extending shelf-life of fresh squids. © 2015 Institute of Food Technologists®

  15. The biology and ecology of the jumbo squid Dosidicus gigas (Cephalopoda in Chilean waters: a review

    Directory of Open Access Journals (Sweden)

    Christian M Ibáñez

    2015-07-01

    Full Text Available ABSTRACT. The jumbo squid Dosidicus gigas is the most abundant cephalopod species in the southeastern Pacific Ocean, which supports the biggest cephalopod fishery in the world. Due to its growing economic importance, the population growth and distributional expansion of this squid is being increasingly studied. Nevertheless, some basic features of the biology of D. gigas are still unknown or have been poorly investigated. In this review we summarize the known information regarding the biology and ecology of this species in the southeastern Pacific Ocean; we focus on the Chilean region in order to propose hypotheses and research lines for a better understanding the life history of this organism. Available data on the size structure, reproduction and genetics of D. gigas allows us to propose hypotheses related to the squid's life history traits. Based on the current literature and publications of colleagues, we propose two hypotheses regarding the effect of spatial variation on the life history of D. gigas. Hypothesis 1: Squids mature at large sizes and spawn in oceanic waters with warm temperatures where paralarvae and juveniles develop. Immature squids migrate near shore to feed, grow and mature, and then return to the offshore sites to spawn. Hypothesis 2: Alternatively, juvenile D. gigas in the oceanic zone do not migrate to coastal waters and mature at small sizes compared to individuals living near the coast that mature at larger size and migrate to oceanic waters to spawn. We provide background information about the feeding behavior and parasitism of this species, suggesting that D. gigas is an important trophic link in the southeastern Pacific marine ecosystem. However, more studies on the feeding habits, reproduction and parasite load are needed not only to test hypotheses proposed in this study, but also to advance the overall knowledge of this species.

  16. Design and Characterization of Low-noise Dewar for High-sensitivity SQUID Operation

    International Nuclear Information System (INIS)

    Yu, K. K.; Lee, Y. H.; Kim, K.; Kwon, H.; Kim, J. M.

    2010-01-01

    We have fabricated the low noise liquid helium(LHe) dewar with a different shape of thermal shield to apply the 64-channel SQUID(Superconducting Quantum Interference Device) gradiometer. The first shape of thermal shield was made of an aluminum plate with a wide width of 100 mm slit and the other shape was modified with a narrow width of 20 mm slit. The two types of dewars were estimated by comparing the thermal noise and the signal-to-noise ratio(SNR) of magnetocardiography(MCG) using the 1st order SQUID gradiometer system cooled each dewar. The white noise was different as a point of the dewar. The noise was increased as close as the edge of dewar, and also increased at the thermal shield with the more wide width slit. The white noise of the dewar with thermal shield of 100 mm slit was 6.5 fT/Hz 1/2 at the center of dewar and 25 fT/Hz 1/2 at the edge, and the white noise of the other one was 3.5 - 7 fT/Hz 1/2 . We measured the MCG using 64-channel SQUID gradiometer cooled at each LHe dewar and compared the SNR of MCG signal. The SNR was improved of 10 times at the LHe dewar with a modified thermal shield.

  17. A mass stranding of the squid martialia hyadesi Rochebrune and ...

    African Journals Online (AJOL)

    1997-02-11

    Feb 11, 1997 ... All animals were immature, with females in lower stages of maturity than males. No predatory marine mammals were seen in the area during or after the stranding event. An interpretation of the stranding is presented with reference to historical reports of squid strandings worldwide. Evidence suggests some ...

  18. Scanning SQUID microscope with an in-situ magnetization/demagnetization field for geological samples

    Science.gov (United States)

    Du, Junwei; Liu, Xiaohong; Qin, Huafeng; Wei, Zhao; Kong, Xiangyang; Liu, Qingsong; Song, Tao

    2018-04-01

    Magnetic properties of rocks are crucial for paleo-, rock-, environmental-magnetism, and magnetic material sciences. Conventional rock magnetometers deal with bulk properties of samples, whereas scanning microscope can map the distribution of remanent magnetization. In this study, a new scanning microscope based on a low-temperature DC superconducting quantum interference device (SQUID) equipped with an in-situ magnetization/demagnetization device was developed. To realize the combination of sensitive instrument as SQUID with high magnetizing/demagnetizing fields, the pick-up coil, the magnetization/demagnetization coils and the measurement mode of the system were optimized. The new microscope has a field sensitivity of 250 pT/√Hz at a coil-to-sample spacing of ∼350 μm, and high magnetization (0-1 T)/ demagnetization (0-300 mT, 400 Hz) functions. With this microscope, isothermal remanent magnetization (IRM) acquisition and the according alternating field (AF) demagnetization curves can be obtained for each point without transferring samples between different procedures, which could result in position deviation, waste of time, and other interferences. The newly-designed SQUID microscope, thus, can be used to investigate the rock magnetic properties of samples at a micro-area scale, and has a great potential to be an efficient tool in paleomagnetism, rock magnetism, and magnetic material studies.

  19. Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones

    Institute of Scientific and Technical Information of China (English)

    LIU Bilin; CHEN Xinjun; CHEN Yong; TIAN Siquan; LI Jianhua; FANG Zhou; YANG Mingxia

    2013-01-01

    Age,maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones (EEZ) during 2008-2010.Estimated ages ranged from 144 to 633 days,confirming that the squid is a short-lived species with longevity no longer than 2 years.Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round.Back-calculated hatching dates for the samples were from January 22nd,2008 to April 22nd,2010 with a peak between January and March.Two size-based and two hatching date-based populations could be defined from mantle length (ML) at maturity and back-calculated hatching dates,respectively.Females matured at a larger size than males,and there was a significant difference in ML at maturity between the two hatching groups (P<0.05).The waters adjacent to 11°S off the Peruvian EEZ may be a potential spawning ground.This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ,which should be considered in the assessment and management of this important resource.

  20. PENGARUH ILUMINASI ATRAKTOR CAHAYA TERHADAP HASIL TANGKAPAN IKAN PADA BAGAN APUNG PELABUHAN RATU

    Directory of Open Access Journals (Sweden)

    Regi Fiji Anggawangsa

    2016-04-01

    Full Text Available Atraktor cahaya sebagai alat bantu penangkapan banyak digunakan untuk mengumpulkan ikan pada alat tangkap bagan apung. Tiga macam atraktor cahaya, yaitu petromaks minyak tanah (dengan iluminasi maksimal 80 lux, petromaks gas (dengan iluminasi maksimal 60 lux, dan lampu genset (dengan iluminasi maksimal 500 lux digunakan pada bagan apung di Palabuhanratu. Penelitian ini bertujuan untuk mengetahui pengaruh perbedaan iluminasi cahaya pada ketiga macam sumber cahaya tersebut terhadap hasil tangkapan bagan apung. Metode yang digunakan adalah eksperimen penangkapan ikan dengan menggunakan tiga jenis atraktor cahaya pada bagan apung. Hasil penelitian menunjukkan perbedaan iluminasi atraktor cahaya pada bagan apung berpengaruh terhadap komposisi hasil tangkapan. Hasil tangkapan bagan pada saat menggunakan atraktor cahaya petromaks minyak tanah (80 lux didominasi oleh ikan layur (Trichiurus spp. yang mencapai lebih dari 50%, petromaks gas (60 lux didominasi oleh ikan layur (Trichiurus spp. dan cumi-cumi (Loligo spp. sedangkan untuk atraktor lampu genset (500 lux didominasi oleh layur dan cumi-cumi.   Light attractor has been used as a fishing device to gather fish schooling on lift net. There are three types of light attractors i.e. kerosene pressure lamp, gas pressure lamp and genset lamp used by Palabuhanratu’s lift net. The aim of this research is to investigate the effect of those light attractors on the lift net catches. The experimental fishing method was used. The results show that illumination produced by genset lamp was higher (500 lux than the two other light attractors at all observation positions with maximum illumination obtained of 80 lux for kerosene pressure lamp and 60 lux for gas pressure lamp. Catch of lift net when using kerosene pressure lamp attractor (80 lux was dominated by hairtail fish (Trichiurus spp. that reaches more than 50%, gas kerosene lamps attractor (60 lux was dominated by fish Layur (Trichiurus spp. and squid

  1. Hypoxia tolerance and antioxidant defense system of juvenile jumbo squids in oxygen minimum zones

    Science.gov (United States)

    Trübenbach, Katja; Teixeira, Tatiana; Diniz, Mário; Rosa, Rui

    2013-10-01

    Jumbo squid (Dosidicus gigas) is a large oceanic squid endemic off the Eastern Tropical Pacific that undertakes diel vertical migrations into mesopelagic oxygen minimum zones. One of the expected physiological effects of such migration is the generation of reactive oxygen species (ROS) at the surface, promoted by the transition between hypoxia and reoxygenation states. The aim of this study was to investigate the energy expenditure rates and the antioxidant stress strategies of juvenile D. gigas under normoxia and hypoxia, namely by quantifying oxygen consumption rates, antioxidant enzyme activities [including superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST)], heat shock protein expression (Hsp70/Hsc70), and lipid peroxidation [malondialdehyde (MDA) levels]. A high significant decrease (68%) in squid's metabolic rates was observed during hypoxia (p0.05), with the latter indicating no enhancement of lipid peroxidation (i.e. cellular damage) at the warmer and normoxic surface waters. The understanding of such physiological strategies that are linked to oxygen deprivation and reoxygenation phases may provide valuable information about how this species is quickly responding to the impacts of environmental stressors coupled with global climate change.

  2. Spawning pattern of the neon flying squid Ommastrephes bartramii (Cephalopoda: Oegopsida around the Hawaiian Islands

    Directory of Open Access Journals (Sweden)

    Dharmamony Vijai

    2014-12-01

    Full Text Available The neon flying squid, Ommastrephes bartramii, is an oceanic squid species that is widely distributed in the North Pacific, with the winter-spring cohort spawning around the Hawaiian Islands. Here, we investigated the spawning characteristics of O. bartramii by analyzing various reproductive parameters of individuals (622 males, 108 females collected in this region. Female spawning status was determined from the somatic indices and histological characteristics of the ovaries. At all developmental stages, the ovaries of spawned females contained oocytes, and oviduct fullness was not correlated with body size. Thus, because the eggs mature asynchronously, with multiple filling and evacuation events, this species is considered an intermittent spawner. Mature males with developed accessory glands were also present within the distribution range of healthy spawned females, indicating that mating occurs between spawning events. Our data indicate that the first spawning event occurs at a mantle length of ~520-540 mm for Hawaiian O. bartramii. Subsequently, the squid forage and grow, and refill the oviducts, before the second spawning event occurs.

  3. Macroalgal diversity along an inshore-offshore environmental gradient in the Jakarta Bay - Thousand Islands reef complex, Indonesia

    Science.gov (United States)

    Draisma, Stefano G. A.; Prud'homme van Reine, Willem F.; Herandarudewi, Sekar M. C.; Hoeksema, Bert W.

    2018-01-01

    The Jakarta Bay - Thousand Islands reef complex extends to more than 80 km in northwest direction from the major conurbation Jakarta (Indonesia) along a pronounced inshore to offshore environmental gradient. The present study aims to determine to what extent environmental factors can explain the composition of macroalgal communities on the reefs off Jakarta. Therefore, the presence-absence of 67 macroalgal taxa was recorded for 27 sampling sites along the inshore-offshore disturbance gradient and analysed with substrate variables and water quality variables. The macroalgal richness pattern matches the pattern of other reef taxa. The 27 sites could be assigned to one of four geographical zones with 85% certainty based on their macroalgal taxon assemblages. These four zones (i.e., Jakarta Bay and, respectively, South, Central, and North Thousand Islands) had significantly different macroalgal assemblages, except for the North and South zones. Along the nearshore gradient there was a greater shift in taxon composition than within the central Thousand Islands. The patterns of ten habitat and water quality variables resembled the macroalgal diversity patterns by 56%. All ten variables together explained 69% of the variation in macroalgal composition. Shelf depth, % sand cover, gelbstoff/detrital material, chlorophyll a concentration, seawater surface temperature, and % dead coral cover were the best predictors of seaweed flora composition. Furthermore, 44 macroalgal species represented new records for the area. The present study provides important baseline data of macroalgae in the area for comparison in future biodiversity assessments in the area and elsewhere in the region.

  4. Site-specific variation in gene expression from Symbiodinium spp. associated with offshore and inshore Porites astreoides in the lower Florida Keys is lost with bleaching and disease stress.

    Science.gov (United States)

    Salas, Briana Hauff; Haslun, Joshua A; Strychar, Kevin B; Ostrom, Peggy H; Cervino, James M

    2017-01-01

    Scleractinian coral are experiencing unprecedented rates of mortality due to increases in sea surface temperatures in response to global climate change. Some coral species however, survive high temperature events due to a reduced susceptibility to bleaching. We investigated the relationship between bleaching susceptibility and expression of five metabolically related genes of Symbiodinium spp. from the coral Porites astreoides originating from an inshore and offshore reef in the Florida Keys. The acclimatization potential of Symbiodinium spp. to changing temperature regimes was also measured via a two-year reciprocal transplant between the sites. Offshore coral fragments displayed significantly higher expression in Symbiodinium spp. genes PCNA, SCP2, G3PDH, PCP and psaE than their inshore counterparts (pzooxanthellae observed under conditions of chronic moderate stress is lost under the acute extreme conditions studied here.

  5. Symplectin evolved from multiple duplications in bioluminescent squid

    DEFF Research Database (Denmark)

    Francis, Warren R.; Christianson, Lynne M.; Haddock, Steven H.D.

    2017-01-01

    The squid Sthenoteuthis oualaniensis, formerly Symplectoteuthis oualaniensis, generates light using the luciferin coelenterazine and a unique enzyme, symplectin. Genetic information is limited for bioluminescent cephalopod species, so many proteins, including symplectin, occur in public databases...... functioning is conserved across essentially all members of the protein family, even those unlikely to be used for bioluminescence. Conversely, active site residues involved in pantetheinase catalysis are also conserved across essentially all of these proteins, suggesting that symplectin may have multiple...

  6. Detecting damage in steel with scanning SQUID microscopy

    International Nuclear Information System (INIS)

    Lee, Tae-Kyu; Clatterbuck, D.M.; Morris, J.W. Jr.; Shaw, T.J.; Lee, Seungkyun; Clarke, John

    2002-01-01

    A 'Holy Grail' of NDE research is a non-destructive method for measuring fatigue damage prior to crack initiation. High-Tc scanning SQUID microscopy may be a useful tool. Because of the exceptional magnetic sensitivity of this technique, fatigue damage can be detected well before microcrack initiation, and in the absence of other obvious microstructure or property changes. Given the spatial resolution of the technique, undamaged material can be located and used to set internal standards

  7. Detecting damage in steel with scanning SQUID microscopy

    International Nuclear Information System (INIS)

    Lee, Tae-Kyu; Clatterbuck, David; Morris Jr., J.W.; Shaw, T.J.; McDermott R.; Clarke, John

    2001-01-01

    A ''Holy Grail'' of NDE research is a non-destructive method for measuring fatigue damage prior to crack initiation. High-Tc scanning SQUID microscopy may be a useful tool. Because of the exceptional magnetic sensitivity of this technique, fatigue damage can be detected well before microcrack initiation, and in the absence of other obvious microstructure or property changes. Given the spatial resolution of the technique, undamaged material can be located and used to set internal standards

  8. Magnetorelaxometry of few Fe3O4 nanoparticles at 77 K employing a self-compensated SQUID magnetometer

    International Nuclear Information System (INIS)

    Guillaume, Alexander; Scholtyssek, Jan M.; Lak, Aidin; Kassner, Alexander; Ludwig, Frank; Schilling, Meinhard

    2016-01-01

    Magnetic nanoparticles (MNPs) are of great interest for industrial and medical applications. Therefore, the properties of the particles have to be well controlled. Several magnetic measurement schemes have been developed in order to determine particle parameters such as size distribution and structural properties. In general, systems are designed either for the analysis of large amounts of MNP (≫1000) or for single particle investigation. Up to now, the region in between has been less studied. However, small and well defined amounts of MNPs are of high interest, e.g. for the systematic investigation of particle–particle interactions. In this paper, we present a method using electron beam lithographic preparation of small amounts of MNPs directly on a self-compensating high-temperature superconducting quantum interference device (SQUID) with micrometer dimensions which is insensitive to homogeneous fields and first order gradients but very sensitive to internal magnetic dipole fields. Magnetorelaxometry (MRX) measurements were carried out at 77 K sample temperature in a magnetically shielded room in order to analyze the dynamic behavior of MNP samples and to evaluate the detection limit of our SQUID sensors. Calculations based on the magnetic moment superposition model (MSM) and finite element simulations (FEM) indicate that the MNP samples can be fabricated in a well-defined way by the presented method. Based on MRX measurements of a sample with 200 single-core magnetite MNPs with core diameters of 12 nm, we estimate the detection limit of our SQUID MRX setup as 70 MNPs. - Highlights: • Novel self-compensated superconducting quantum interference device (SQUID). • Electron-beam lithographical patterning of magnetic nanoparticles directly on SQUID. • Magnetorelaxometric detection of 200 nanoparticles with diameter of 12 nm at 77 K. • FEM simulations provide detection limit of less than 100 nanoparticles.

  9. Squids old and young: Scale-free design for a simple billboard

    Science.gov (United States)

    Packard, Andrew

    2011-03-01

    Squids employ a large range of brightness-contrast spatial frequencies in their camouflage and signalling displays. The 'billboard' of coloured elements ('spots'=chromatophore organs) in the skin is built autopoietically-probably by lateral inhibitory processes-and enlarges as much as 10,000-fold during development. The resulting two-dimensional array is a fractal-like colour/size hierarchy lying in several layers of a multilayered network. Dynamic control of the array by muscles and nerves produces patterns that recall 'half-tone' processing (cf. ink-jet printer). In the more sophisticated (loliginid) squids, patterns also combine 'continuous tones' (cf. dye-sublimation printer). Physiologists and engineers can exploit the natural colour-coding of the integument to understand nerve and muscle system dynamics, examined here at the level of the ensemble. Integrative functions of the whole (H) are analysed in terms of the power spectrum within and between ensembles and of spontaneous waves travelling through the billboard. Video material may be obtained from the author at the above address.

  10. Halide peroxidase in tissues that interact with bacteria in the host squid Euprymna scolopes.

    Science.gov (United States)

    Small, A L; McFall-Ngai, M J

    1999-03-15

    An enzyme with similarities to myeloperoxidase, the antimicrobial halide peroxidase in mammalian neutrophils, occurs abundantly in the light organ tissue of Euprymna scolopes, a squid that maintains a beneficial association with the luminous bacterium Vibrio fischeri. Using three independent assays typically applied to the analysis of halide peroxidase enzymes, we directly compared the activity of the squid enzyme with that of human myeloperoxidase. One of these methods, the diethanolamine assay, confirmed that the squid peroxidase requires halide ions for its activity. The identification of a halide peroxidase in a cooperative bacterial association suggested that this type of enzyme can function not only to control pathogens, but also to modulate the interactions of host animals with their beneficial partners. To determine whether the squid peroxidase functions under both circumstances, we examined its distribution in a variety of host tissues, including those that typically interact with bacteria and those that do not. Tissues interacting with bacteria included those that have specific cooperative associations with bacteria (i.e., the light organ and accessory nidamental gland) and those that have transient nonspecific interactions with bacteria (i.e., the gills, which clear the cephalopod circulatory system of invading microorganisms). These bacteria-associated tissues were compared with the eye, digestive gland, white body, and ink-producing tissues, which do not typically interact directly with bacteria. Peroxidase enzyme assays, immunocytochemical localization, and DNA-RNA hybridizations showed that the halide-dependent peroxidase is consistently expressed in high concentration in tissues that interact bacteria. Elevated levels of the peroxidase were also found in the ink-producing tissues, which are known to have enzymatic pathways associated with antimicrobial activity. Taken together, these data suggest that the host uses a common biochemical response to

  11. Growth and optical development of the ocular lens of the squid (Sepioteuthis lessoniana).

    Science.gov (United States)

    Sivak, J G; West, J A; Campbell, M C

    1994-09-01

    Lens focal properties (spherical aberration), diameter and relative anterior/posterior proportions were measured photographically for Japanese squid (Sepioteuthis lessoniana) at ages 4-6 weeks, 7-9 weeks and 7-8 months. The measures involved photographing the refractive effects of lenses in a physiological solution, with and without an index matching fluid (polyvinylpyrroloidone solution), on a parallel array of fine helium-neon laser beams. Spherical aberration was determined from measurement of back vertex distance. Similar measurements were made on lenses from the eyes of cuttlefish (Sepia officinalis). The cephalopod lens develops as hemispheric halves from separate ectodermal sources. The posterior component contributes, on average, about 60% of axial lens diameter in S. lessoniana of all ages and 55% in S. officinalis. However, these proportions vary widely in both species. All lenses of both species show that spherical aberration is neutralized, although small variations in back vertex distance (positive and negative spherical aberration) were measured. Preliminary measures indicate that the refractive index distribution within the cephalopod lens varies in a manner reminiscent of teleost lenses. Squid lenses from animals 7-9 weeks of age were optimally corrected for spherical aberration. Some squid of this age, from a separate tank, showed a high incidence of cataract development. In each case, lens opacification was caused by deterioration of the posterior lens component.

  12. Preparation and evaluation of squid ink polysaccharide-chitosan as a wound-healing sponge.

    Science.gov (United States)

    Huang, Na; Lin, Jiali; Li, Sidong; Deng, Yifeng; Kong, Songzhi; Hong, Pengzhi; Yang, Ping; Liao, Mingneng; Hu, Zhang

    2018-01-01

    A new type of wound healing agent was developed using two marine biomaterials (squid ink polysaccharide and chitosan) as carriers and calcium chloride as an initiator for coagulation. Based on central composite design-response surface methodology, comprehensive evaluation of appearance quality for composite sponges and water absorbency were used as evaluation indices to identify the optimized preparation conditions and further evaluate the performance of the squid ink polysaccharide-chitosan sponge (SIP-CS). The optimized formulation of SIP-CS was as follows: chitosan concentration, 2.29%; squid ink polysaccharide concentration, 0.55%; and calcium chloride concentration, 2.82%, at a volume ratio of 15:5:2. SIP-CS was conducive to sticking on the wound, characterized by the spongy property, strong absorptivity, and tackiness. Rabbit ear arterial, hepatic, and femoral artery hemorrhage experiments indicated that, compared with chitosan dressings and absorbable gelatin, the hemostatic times were shorter and the bleeding volume was smaller. Furthermore, SIP-CS absorbed a large amount of hemocytes, leading to rapid hemostasis. The healing areas and wound pathological sections in scalded New Zealand rabbits indicated that SIP-CS promoted wound healing more rapidly than chitosan and better than commercially available burn cream. Thus, SIP-CS is a good wound healing agent for rapid hemostasis, promoting burn/scalded skin healing, and protecting from wound infection. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Squid based beam current meter

    International Nuclear Information System (INIS)

    Kuchnir, M.

    1983-01-01

    A SQUID based beam current meter has the capability of measuring the current of a beam with as little as 30 x 155 antiprotons (with a signal to noise ratio of 2). If low noise dc current is used to cancel most of the beam or an up-down counter is used to count auto-resets this sensitivity will be available at any time in the acumulation process. This current meter will therefore be a unique diagnostic tool for optimizing the performance of several Tev I components. Besides requiring liquid helium it seems that its only drawback is not to follow with the above sensitivity a sudden beam change larger than 16 μA, something that could be done using a second one in a less sensitive configuration

  14. Absolute calibration and beam background of the Squid Polarimeter

    International Nuclear Information System (INIS)

    Blaskiewicz, M.M.; Cameron, P.R.; Shea, T.J.

    1996-01-01

    The problem of beam background in Squid Polarimetry is not without residual benefits. The authors may deliberately generate beam background by gently kicking the beam at the spin tune frequency. This signal may be used to accomplish a simple and accurate absolute calibration of the polarimeter. The authors present details of beam background calculations and their application to polarimeter calibration, and suggest a simple proof-of-principle accelerator experiment

  15. Exposure of inshore corals to suspended sediments due to wave-resuspension and river plumes in the central Great Barrier Reef: A reappraisal

    Science.gov (United States)

    Orpin, Alan R.; Ridd, Peter V.

    2012-09-01

    Suspended sediment in the coastal zone is an important limiting factor for the growth and health of inshore coral reefs. The Great Barrier Reef (GBR) lagoon receives sediment from a number of tropical rivers and the physical and biological effects of riverine discharge and turbidity within the lagoon are of considerable scientific and public interest. Published data from two inshore regions of the GBR are reviewed herein to evaluate the relative influence of river plumes and wave resuspension on suspended sediment concentration (SSC) around coral communities over a range of timescales. Data from Cleveland Bay and from other sites near the mouth of the Tully River show that wave resuspension is the most dominant mechanism controlling SSC at inshore reefs. At many nearshore areas today fine-grained bed sediment is abundant, consistent with millennial-scale geological evidence of sediment dispersal prior to European settlement and catchment impacts. Flocculation, particle settling and dilution occurs within the river plume, and riverine sediment concentrations at reefs directly attributable to individual flood inputs is significantly reduced, suggesting that the plume component is a relatively small contribution to the total suspended sediment mass balance over inter-annual timescales. Resuspension events can generate higher ambient SSC than that measured in flood waters (e.g. Tully River). In addition, while visually spectacular, satellite and aerial images offer limited quantitative information of total sediment load carried by hypopycnal plumes, as many of these plumes may contain algal blooms but relatively low concentrations of suspended sediment (ca. processes common to many continental shelves globally. Despite the examples examined in detail herein, the role of frequency, magnitude and duration in determining the impact or exposure of corals to elevated SSCs is poorly constrained by limited quantitative measurements during events, and our ability to place

  16. Fishing ground distribution of neon flying squid ( Ommastrephes bartramii) in relation to oceanographic conditions in the Northwest Pacific Ocean

    Science.gov (United States)

    Yu, Wei; Chen, Xinjun; Yi, Qian

    2017-12-01

    Neon flying squid, Ommastrephes bartramii, is a squid species of the North Pacific Ocean, which plays an important economical role in the international fishery. Logbook data for Chinese squid-jigging fishery over 2004-2011 were used to evaluate the relationship between the fishing grounds of the squid and the convergent frontal areas, which were defined by the contour lines of specific sea surface temperature (SST) and chlorophyll- a (Chl- a) concentration. Our results indicate that the SST in the range of 15 to 19°C and the Chl- a concentration in the range of 0.1 to 0.4 mg m-3 are the favorable conditions for the aggregation of the squid. Additionally, we deduced that the SST at 17.5°C and the Chl- a concentration at 0.25 mg m-3 are the optimal environmental conditions for the aggregation of O. bartramii. In August, the annual CPUE is positively correlated with the proportion of the fishing grounds with favorable SST and Chl- a concentration, as well as the combination of the two variables, implying that the abundance of the squid annually is largely depending on the presence of the favorable environmental conditions for fishery in August. Minor spatial difference between mean latitudinal location of the 17.5°C SST and 0.25 mg m-3 Chl- a fronts can increase the CPUEs of O. bartramii. Furthermore, the monthly latitudinal gravity centers of the CPUE closely followed the mean latitudinal position of the contour lines of the 17.5°C SST and the 0.25 mg m-3 Chl- a concentration. Our findings suggest the convergent oceanographic features (fronts) play significant roles in regulating the distribution and abundance of the western stock of the winter-spring cohort of O. bartramii, which can help people to improve their ability to discover the O. bartramii fishing grounds with higher productivity.

  17. Imaging, manipulation and flux noise of single Abrikosov vortices in YBa2Cu3O7-δ dc SQUIDs

    International Nuclear Information System (INIS)

    Bailer, Matthias

    2013-01-01

    The thesis deals with the imaging and investigation of single Abrikosov vortices in grain boundary dc SQUIDs1 from the high-temperature superconductor YBa 2 Cu 3 O 7-δ . The low temperature scanning electron microscopy (LTSEM) was used for the measurements, which makes a local, spatially resolved investigation of the electrical properties of materials at low temperatures possible. The advantage over other flux quantum imaging methods is the facility to determine the low-frequency flux noise in the SQUID in the process. Special SQUID designs were created, which allow a reproducible cooling of single flux quanta. Electrical transport and noise measurements were carried out to precharacterise the SQUIDs. Within the scope of the thesis it was the first time that antivortices were imaged with the LTSEM. The possibilities of a manipulation of flux quanta (with the electron beam) were investigated and illustrated. By the averaged measurement of the waveform of a single vortex, linescans with unprecedented resolution could be obtained. This allowed the outstanding comparison of the measured, virtual vortex displacement with various theoretically determined waveforms. The experiments to flux noise provided new insights into the noise behaviour of single flux quanta, which exhibit the typical single fluctuators random telegraph signal, and enabled the analysis of the associated hopping processes. Thus concrete values of the spectral noise power density S r ∼ 196 nm 2 /root(Hz) - 0,28 μm 2 /root(Hz) radially to the SQUID hole could be determined by different, pinned vortices. An influence of the hopping behaviour and therefore of the flux noise succeeded by varying an applied magnetic field. Through tilting the potential course of a vortex, the course of the pinning potential by different hopping processes could be reconstructed using stochastic analysis of the time trace data. With the thesis could be shown convincingly that the vortex imaging method of the LTSEM in

  18. A simple method for checking the balance of gradiometers used with squids

    International Nuclear Information System (INIS)

    Eghrari, I.R.; Ribeiro, P.C.

    1978-11-01

    A simple technique for detecting the degree of balance of first order gradiometers before connecting them to the SQUID is described. The effect of thermal cycling on this balance is given for different materials used in the construction of the gradiometers [pt

  19. Microfossil evidence for a mid-Jurassic squid egg-laying area in association with the Christian Malford Lagerstätte

    Science.gov (United States)

    Hart, Malcolm; de Jonghe, Alex; Duff, Keith; Page, Kevin; Price, Gregory; Smart, Christopher; Wilby, Philip

    2010-05-01

    In the 1840s, during the construction of the Great Western Railway west of Swindon, a number of beautifully preserved coleoids (belemnites and squid-like cephalopods) were found. These famous specimens of Belemnoteuthis and Mastigophora, as well as a number of fish, were eventually described as a fossil lagerstätte under the name of the "Christian Malford Squid Bed". Many of these specimens, which come from the Phaeinum Zone (Callovian) of the Oxford Clay Formation, contain soft tissue, muscle fibres and the content of their ink sacs. In October 2007 the British Geological Survey funded an excavation of the site some ~100 m from the original borrow pits alongside the railway. This pit yielded some new coleoid specimens as well as many ammonites, bivalves and gastropods, all of which are exquisitely preserved. Some of the bedding surfaces recovered are plastered with monospecific assemblages of foraminifera (In the 1840s, during the construction of the Great Western Railway west of Swindon, a number of beautifully preserved coleoids (belemnites and squid-like cephalopods) were found. These famous specimens of Belemnoteuthis and Mastigophora, as well as a number of fish, were eventually described as a fossil lagerstätte under the name of the "Christian Malford Squid Bed". Many of these specimens, which come from the Phaeinum Zone (Callovian) of the Oxford Clay Formation, contain soft tissue, muscle fibres and the content of their ink sacs. In October 2007 the British Geological Survey funded an excavation of the site some ~100 m from the original borrow pits alongside the railway. This pit yielded some new coleoid specimens as well as many ammonites, bivalves and gastropods, all of which are exquisitely preserved. Some of the bedding surfaces recovered are plastered with monospecific assemblages of foraminifera (Epistomina spp.). Our work on borehole core No. 10 (from the same location) has recovered exceptionally large numbers of statoliths, otoliths (fish

  20. AFSC/REFM: Inshore research surveys in the eastern and central Gulf of Alaska, 2010-2013, conducted by the middle trophic level component of the GOA Integrated Ecosystem Research Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains the results of a series of inshore research surveys that took place during 2010-2013 as part of the Gulf of Alaska Integrated Ecosystem...

  1. Phylogeographical patterns among Mediterranean sepiolid squids and their Vibrio symbionts: environment drives specificity among sympatric species.

    Science.gov (United States)

    Zamborsky, D J; Nishiguchi, M K

    2011-01-01

    Bobtail squid from the genera Sepiola and Rondeletiola (Cephalopoda: Sepiolidae) form mutualistic associations with luminous Gram-negative bacteria (Gammaproteobacteria: Vibrionaceae) from the genera Vibrio and Photobacterium. Symbiotic bacteria proliferate inside a bilobed light organ until they are actively expelled by the host into the surrounding environment on a diel basis. This event results in a dynamic symbiont population with the potential to establish the symbiosis with newly hatched sterile (axenic) juvenile sepiolids. In this study, we examined the genetic diversity found in populations of sympatric sepiolid squid species and their symbionts by the use of nested clade analysis with multiple gene analyses. Variation found in the distribution of different species of symbiotic bacteria suggests a strong influence of abiotic factors in the local environment, affecting bacterial distribution among sympatric populations of hosts. These abiotic factors include temperature differences incurred by a shallow thermocline, as well as a lack of strong coastal water movement accompanied by seasonal temperature changes in overlapping niches. Host populations are stable and do not appear to have a significant role in the formation of symbiont populations relative to their distribution across the Mediterranean Sea. Additionally, all squid species examined (Sepiola affinis, S. robusta, S. ligulata, S. intermedia, and Rondeletiola minor) are genetically distinct from one another regardless of location and demonstrate very little intraspecific variation within species. These findings suggest that physical boundaries and distance in relation to population size, and not host specificity, are important factors in limiting or defining gene flow within sympatric marine squids and their associated bacterial symbionts in the Mediterranean Sea.

  2. Detection of thermal aging degradation and plastic strain damage for duplex stainless steel using SQUID sensor

    International Nuclear Information System (INIS)

    Otaka, M.; Evanson, S.; Hesegawa, K.; Takaku, K.

    1991-01-01

    An apparatus using a SQUID sensor is developed for nondestructive inspection. The measurements are obtained with the SQUID sensor located approximately 150 mm from the specimen. The degradation of thermal aging and plastic strain for duplex stainless steel is successfully detected independently from the magnetic characterization measurements. The magnetic flux density under high polarizing field is found to be independent of thermal aging. Coercive force increases with thermal aging time. On the other hand, the magnetic flux density under high field increases with the plastic strain. Coercive force is found to be independent of the plastic strain. (author)

  3. A nitrogen triple-point thermal storage unit for cooling a SQUID magnetometer

    NARCIS (Netherlands)

    Rijpma, A.P.; Meenderink, D.J.; Reincke, H.A.; Venhorst, G.C.F.; Holland, H.J.; Brake, ter H.J.M.

    2005-01-01

    In order to achieve turnkey operation, the use is planned of cryocoolers to cool a SQUID magnetometer system. To minimize the magnetical and mech. interference from the coolers, they are switched off during the actual measurements. Consequently, a thermal storage unit (TSU) is required with

  4. Squid-inspired vehicle design using coupled fluid-solid analytical modeling

    Science.gov (United States)

    Giorgio-Serchi, Francesco; Weymouth, Gabriel

    2017-11-01

    The need for enhanced automation in the marine and maritime fields is fostering research into robust and highly maneuverable autonomous underwater vehicles. To address these needs we develop design principles for a new generation of soft-bodied aquatic vehicles similar to octopi and squids. In particular, we consider the capability of pulsed-jetting bodies to boost thrust by actively modifying their external body-shape and in this way benefit of the contribution from added-mass variation. We present an analytical formulation of the coupled fluid-structure interaction between the elastic body and the ambient fluid. The model incorporates a number of new salient contributions to the soft-body dynamics. We highlight the role of added-mass variation effects of the external fluid in enhancing thrust and assess how the shape-changing actuation is impeded by a confinement-related unsteady inertial term and by an external shape-dependent fluid stiffness contribution. We show how the analysis of these combined terms has guided us to the design of a new prototype of a squid-inspired vehicle tuning of the natural frequency of the coupled fluid-solid system with the purpose of optimizing its actuation routine.

  5. SQUID multiplexing using baseband feedback for space application of transition-edge sensor microcalorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Takei, Y; Yamasaki, N Y; Hirakoso, W; Kimura, S; Mitsuda, K, E-mail: takei@astro.isas.jaxa.j [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, 229-8510 (Japan)

    2009-11-15

    A microcalorimeter array based on a transition-edge sensor (TES) thermometer is a promising imaging spectrometer for use in future x-ray astronomy missions. A TES microcalorimeter achieves {approx}<5 eV energy resolution and an array of >100 pixels also provides a moderate imaging capability. For a large format array, signal multiplexing at the low temperature stage is mandatory in order to reduce heat loads from cold stage preamplifiers and through wirings. We are developing frequency division multiplexing (FDM). In FDM, each TES is ac-biased with a different carrier frequency. Signals from several pixels are summed and then read out by one dc SQUID (superconducting quantum interference device). The maximum number of multiplexed pixels is limited by the bandwidth of a SQUID in a flux-locked loop. Assuming 1 m cable length between the room temperature and the cold stage, the bandwidth is only <1 MHz with a standard flux-locked loop, due to the delay and phase shift of wirings. We report our development of baseband feedback, a new feedback scheme that overcomes the bandwidth limitation. In baseband feedback, the signal ({approx}<10 kHz) from the TES is sent back to the SQUID after the phase of carrier frequency ({approx}1 MHz) has been adjusted. We demonstrated open-loop gain of 8 for 10 kHz signal at 5 MHz carrier frequency, which indicates the possibility of {approx}40-pixel multiplexing of the TES signal.

  6. Impact of SQUIDs on functional imaging in neuroscience

    International Nuclear Information System (INIS)

    Penna, Stefania Della; Pizzella, Vittorio; Romani, Gian Luca

    2014-01-01

    This paper provides an overview on the basic principles and applications of magnetoencephalography (MEG), a technique that requires the use of many SQUIDs and thus represents one of the most important applications of superconducting electronics. Since the development of the first SQUID magnetometers, it was clear that these devices could be used to measure the ultra-low magnetic signals associated with the bioelectric activity of the neurons of the human brain. Forty years on from the first measurement of magnetic alpha rhythm by David Cohen, MEG has become a fundamental tool for the investigation of brain functions. The simple localization of cerebral sources activated by sensory stimulation performed in the early years has been successively expanded to the identification of the sequence of neuronal pool activations, thus decrypting information of the hierarchy underlying cerebral processing. This goal has been achieved thanks to the development of complex instrumentation, namely whole head MEG systems, allowing simultaneous measurement of magnetic fields all over the scalp with an exquisite time resolution. The latest trends in MEG, such as the study of brain networks, i.e. how the brain organizes itself in a coherent and stable way, are discussed. These sound applications together with the latest technological developments aimed at implementing systems able to record MEG signals and magnetic resonance imaging (MRI) of the head with the same set-up pave the way to high performance systems for brain functional investigation in the healthy and the sick population. (paper)

  7. NOAA ESRI Geotiff- 1m Multibeam Bathymetry of NPS's Virgin Islands Coral Reef National Monument (Inshore), St. John, US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Geotiff with 1 meter cell size representing the bathymetry of an inshore portion of the NPS's Virgin Islands Coral Reef National...

  8. TlCu1.73Fe0.27Se2 studied by means of Moessbauer spectroscopy and SQUID magnetometry

    International Nuclear Information System (INIS)

    Kamali-M, S; Ericsson, T; Haeggstroem, L; Berger, R; Ronneteg, S; Felton, S

    2006-01-01

    TlCu 2-x Fe x Se 2 is a p-type metal for x c is 55(5) K as found from both SQUID and Moessbauer spectra. At T c the magnetic hyperfine fields are distributed with a maximum at about 30 T, which are compared to the measured magnetic moment per iron atom, which is 0.97 μ B /Fe as found from SQUID measurements. The experimental results are compared to results using other methods on isostructural Tl selenides

  9. A nitrogen triple-point thermal storage unit for cooling a SQUID magnetometer

    NARCIS (Netherlands)

    Rijpma, A.P.; Meenderink, D.J.; Reincke, H.A.; Venhorst, G.C.F.; Venhorst, G.C.F.; Holland, Herman J.; ter Brake, Hermanus J.M.

    2005-01-01

    In order to achieve turnkey operation, we plan to use cryocoolers to cool a SQUID magnetometer system. To minimize the magnetical and mechanical interference from the coolers, we intend to switch them off during the actual measurements. Consequently, a thermal storage unit (TSU) is required with

  10. Issues relating to airborne applications of HTS SQUIDs

    International Nuclear Information System (INIS)

    Foley, C P; Leslie, K E; Binks, R A; Lam, S H K; Du, J; Tilbrook, D L; Mitchell, E E; Macfarlane, J C; Lee, J B; Turner, R; Downey, M; Maddever, A

    2002-01-01

    Airborne application of HTS SQUIDs is the most difficult environment for their successful deployment. In order to operate with the sensitivity required for a particular application, there are many issues to be addressed such as the need for very wide dynamic range electronics, motion noise elimination, immunity to large changing magnetic fields and cultural noise sources. This paper reviews what is necessary to achieve an airborne system giving examples in geophysical mineral exploration. It will consider issues relating to device design and fabrication, electronics, dewar design, suspension system requirements and noise elimination methods

  11. Issues relating to airborne applications of HTS SQUIDs

    CERN Document Server

    Foley, C P; Binks, R A; Lam, S H K; Du, J; Tilbrook, D L; Mitchell, E E; MacFarlane, J C; Lee, J B; Turner, R; Downey, M; Maddever, A

    2002-01-01

    Airborne application of HTS SQUIDs is the most difficult environment for their successful deployment. In order to operate with the sensitivity required for a particular application, there are many issues to be addressed such as the need for very wide dynamic range electronics, motion noise elimination, immunity to large changing magnetic fields and cultural noise sources. This paper reviews what is necessary to achieve an airborne system giving examples in geophysical mineral exploration. It will consider issues relating to device design and fabrication, electronics, dewar design, suspension system requirements and noise elimination methods.

  12. 3D Inversion of SQUID Magnetic Tensor Data

    DEFF Research Database (Denmark)

    Zhdanov, Michael; Cai, Hongzhu; Wilson, Glenn

    2012-01-01

    Developments in SQUID-based technology have enabled direct measurement of magnetic tensor data for geophysical exploration. For quantitative interpretation, we introduce 3D regularized inversion for magnetic tensor data. For mineral exploration-scale targets, our model studies show that magnetic...... tensor data have significantly improved resolution compared to magnetic vector data for the same model. We present a case study for the 3D regularized inversion of magnetic tensor data acquired over a magnetite skarn at Tallawang, Australia. The results obtained from our 3D regularized inversion agree...

  13. Specific accumulation of polychlorinated biphenyls and organochlorine pesticides in Japanese common squid as a bioindicator

    International Nuclear Information System (INIS)

    Ueno, D.; Inoue, S.; Ikeda, K.; Tanaka, H.; Yamada, H.; Tanabe, S.

    2003-01-01

    Japanese common squid is a suitable bioindicator for monitoring organochlorines pollution in waters around Japan. - Organochlorines (OCs) representing Persistent Organic Pollutants (POPs) such as PCBs (polychlorinated biphenyls), DDTs (DDT and its metabolites), CHLs (chlordane compounds), HCHs (hexachlorocyclohexane isomers) and HCB (hexachlorobenzene) were determined in the liver of Japanese common squid (Todarodes pacificus) collected from the waters around Japan (Japan Sea and western North Pacific Ocean). Among OCs concentrations, PCBs (upto 5600 ng/g lipid wt.) were the highest, and those of other OCs were in the order of DDT> CHLs > HCHs > HCB. Studies on growth trend and seasonal variation of OCs in this species suggest a rapid reflection of the pollution levels in seawater where and when they were collected, regardless of body-length and time of collection. These results indicate that Japanese common squid is a suitable bioindicator for monitoring OCs pollution in waters around Japan. With regard to the geographical distribution of OCs in this species collected from waters around Japan, OCs concentrations in specimens from Japan Sea were higher than those from the Pacific Ocean. This result might reflect some existing of local pollution sources of OCs around Japan Sea, and slower water exchange between Japan Sea and open ocean

  14. Body Size Regression Formulae, Proximate Composition and Energy Density of Eastern Bering Sea Mesopelagic Fish and Squid.

    Science.gov (United States)

    Sinclair, Elizabeth H; Walker, William A; Thomason, James R

    2015-01-01

    The ecological significance of fish and squid of the mesopelagic zone (200 m-1000 m) is evident by their pervasiveness in the diets of a broad spectrum of upper pelagic predators including other fishes and squids, seabirds and marine mammals. As diel vertical migrators, mesopelagic micronekton are recognized as an important trophic link between the deep scattering layer and upper surface waters, yet fundamental aspects of the life history and energetic contribution to the food web for most are undescribed. Here, we present newly derived regression equations for 32 species of mesopelagic fish and squid based on the relationship between body size and the size of hard parts typically used to identify prey species in predator diet studies. We describe the proximate composition and energy density of 31 species collected in the eastern Bering Sea during May 1999 and 2000. Energy values are categorized by body size as a proxy for relative age and can be cross-referenced with the derived regression equations. Data are tabularized to facilitate direct application to predator diet studies and food web models.

  15. Environmental pH, O2 and Capsular Effects on the Geochemical Composition of Statoliths of Embryonic Squid Doryteuthis opalescens

    Directory of Open Access Journals (Sweden)

    Michael O. Navarro

    2014-07-01

    Full Text Available Spawning market squid lay embryo capsules on the seafloor of the continental shelf of the California Current System (CCS, where ocean acidification, deoxygenation and intensified upwelling lower the pH and [O2]. Squid statolith geochemistry has been shown to reflect the squid’s environment (e.g., seawater temperature and elemental concentration. We used real-world environmental levels of pH and [O2] observed on squid-embryo beds to test in the laboratory whether or not squid statolith geochemistry reflects environmental pH and [O2]. We asked whether pH and [O2] levels might affect the incorporation of element ratios (B:Ca, Mg:Ca, Sr:Ca, Ba:Ca, Pb:Ca, U:Ca into squid embryonic statoliths as (1 individual elements and/or (2 multivariate elemental signatures, and consider future applications as proxies for pH and [O2] exposure. Embryo exposure to high and low pH and [O2] alone and together during development over four weeks only moderately affected elemental concentrations of the statoliths, and uranium was an important element driving these differences. Uranium:Ca was eight-times higher in statoliths exposed to low pHT (7.57–7.58 and low [O2] (79–82 µmol·kg−1 than those exposed to higher ambient pHT (7.92–7.94 and [O2] (241–243 µmol·kg−1. In a separate experiment, exposure to low pHT (7.55–7.56 or low [O2] (83–86 µmol·kg−1 yielded elevated U:Ca and Sr:Ca in the low [O2] treatment only. We found capsular effects on multiple elements in statoliths of all treatments. The multivariate elemental signatures of embryonic statoliths were distinct among capsules, but did not reflect environmental factors (pH and/or [O2]. We show that statoliths of squid embryos developing inside capsules have the potential to reflect environmental pH and [O2], but that these “signals” are generated in concert with the physiological effects of the capsules and embryos themselves.

  16. Characteristics regarding the consumer of giant squid from Baja California Sur, Mexico

    Directory of Open Access Journals (Sweden)

    Liliana Enriqueta Montaño Méndez

    2015-01-01

    Full Text Available The catch of the giant squid (Dosidicus gigas, represents de second fishing activity most important in volume in Baja California Sur, Mexico; is an essential specie not only at the state level but at the pacific and even the national level. Mexico occupies in the world the eight level in the production of squid, but the national consumption, even though the low price of the product and the high nutritional level, is approximately 0.53 kg per year, very low compared to countries like Japan, Korea and Spain (average consumption per capita is of 3.5 kg . In this context, the objective of this article is to caracterize the sudcalifornia consumer preference; determine the buying habits and the consumption; and also to establish the market areas of the squid in Baja California Sur, which allows the introduction of actions for its commercialization, in order to strengthen the market of this product and its general activity. This is why in 2012 a questioner of 1066 consumers was distribute around the five counties of the state, according to the population density. The results indicate that the principal motive why there is not consumption is the difficulty to find places where to buy it, together with the problems of cooking it. Also, it can be seen the high level of ignorance the consumer has regarding the nutritional level this food has. For this reason, future strategies for the commercialization must be focus on better distribution and new form of presenting this product which facilitates its preparation and consumption, and at the same time create campaign which increase awareness of the nutrition level this product has.

  17. Development of a Flow-Through SQUID System for Non-Destructive Evaluation of MRI Wire

    National Research Council Canada - National Science Library

    Wellstood, Frederick C

    2007-01-01

    ...) superconducting quantum interference device (SQUID) system. The ability to detect small defects in km-long sections of NbTi magnet wire could improve the production yield of high-field magnets for power and medical applications...

  18. The effects of jig color and lunar bright on coastal squid jigging ...

    African Journals Online (AJOL)

    Squid jigging experiments were carried out to determine whether differences occurred between different colors and lunar brightness in Middle Eastern coast of Aegean Sea. Five different colors of jigs (red, blue, green, orange and white) were used together in same angle. According to one-way analysis of variance results, ...

  19. Analysis of metal catalyst content in magnetically filtered SWCNTs by SQUID magnetometry

    Czech Academy of Sciences Publication Activity Database

    Pacáková, Barbara; Komínková, Zuzana; Vejpravová, Jana; Kalbáč, Martin

    2015-01-01

    Roč. 50, č. 6 (2015), s. 2544-2553 ISSN 0022-2461 R&D Projects: GA ČR GAP204/10/1677 Institutional support: RVO:68378271 ; RVO:61388955 Keywords : single-wall carbon nanotubes * nanoparticles * magnetic filtration * SQUID Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.302, year: 2015

  20. Closed-cycle gas flow system for cooling a HTc dc-SQUID magnetometer

    NARCIS (Netherlands)

    Bosch, van den P.J.; Holland, H.J.; Brake, ter H.J.M.; Rogalla, H.

    1994-01-01

    A closed-cycle gas flow system for cooling a high-crit. temp. d.c.-superconducting quantum interference device (SQUID) magnetometer by means of a cryocooler has been designed, constructed and tested. The magnetometer is aimed to measure heart signals with a sensitivity of 0.1 pT/Hz1/2. The required

  1. K+/Na+-triggered bioluminescence in the oceanic squid Symplectoteuthis oualaniensis

    OpenAIRE

    Tsuji, Frederick I.; Leisman, Gary B.

    1981-01-01

    A distinctive type of luminescent system present in the large dorsal luminous organ of the oceanic squid Symplectoteuthis oualaniensis is described. The organ produces an intense blue flash of light followed by a rapid decay in light intensity. Luminescence originates from numerous oval granules present in the luminous organ. The essential light-emitting components are membrane bound. Intact granules or washed homogenates of the granules are triggered to emit light by monovalent cations such ...

  2. rf SQUID system as tunable flux qubit

    Energy Technology Data Exchange (ETDEWEB)

    Ruggiero, B. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy)]. E-mail: b.ruggiero@cib.na.cnr.it; Granata, C. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Vettoliere, A. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Rombetto, S. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Russo, R. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Russo, M. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Corato, V. [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-81031 Aversa (Italy); Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Silvestrini, P. [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-81031 Aversa (Italy); Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy)

    2006-08-21

    We present a fully integrated rf SQUID-based system as flux qubit with a high control of the flux transfer function of the superconducting transformer modulating the coupling between the flux qubit and the readout system. The control of the system is possible by including into the superconducting flux transformer a vertical two-Josephson-junctions interferometer (VJI) in which the Josephson current is precisely modulated from a maximum to zero by a transversal magnetic field parallel to the flux transformer plane. The proposed system can be also used in a more general configuration to control the off-diagonal terms in the Hamiltonian of the flux qubit and to turn on and off the coupling between two or more qubits.

  3. High critical current density YBCO films and fabrication of dc-SQUIDs

    CERN Document Server

    Kuriki, S; Kawaguchi, Y; Matsuda, M; Otowa, T

    2002-01-01

    In order to improve the sensitivity of SQUID magnetometers made of high-T sub c films, we have studied the conditions of pulsed-laser deposition of YBCO films. Among the different deposition parameters examined, extensive degassing of the vacuum chamber before and precise control of the substrate temperature during the film deposition were found effective for obtaining high critical temperature T sub c and high critical current density J sub c. It was also found that the residual-resistance ratio has a clear correlation with J sub c , indicating that it can be a good, and easy to measure, index of the film quality. Films having T sub c approx 89-90 K and J sub c >= 5x10 sup 6 A cm sup - sup 2 at 77 K were used to fabricate SQUIDs without a pickup loop. Grain-boundary junctions formed on bicrystal substrates with a 30 deg. misorientation angle exhibited I sub c R sub n values of more than 100 mu V at 77 K. The well-known scaling behaviour of the relation I sub c R sub n propor to (J sup G sup B sub c) sup 1 su...

  4. YBCO nanoSQUIDs applied to the investigation of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Perez, Maria Jose; Schwarz, Tobias; Woelbing, Roman; Mueller, Benedikt; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut and Center for Collective Quantum Phenomena in LISA" +, Universitaet Tuebingen (Germany); Reiche, Christopher F.; Muehl, Thomas; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Sese, Javier [Instituto de Nanociencia de Aragon and Advanced Microscopy Laboratory, Zaragoza (Spain)

    2015-07-01

    We present the realization of ultra-sensitive YBCO nanoSQUIDs based on submicron grain boundary junctions patterned by focused ion beam milling. White flux noise down to ∝ 50nΦ{sub 0}/Hz{sup 1/2} has been achieved, yielding spin sensitivities of down to a few μ{sub B}/Hz{sup 1/2} at T=4.2 K. Moreover, we demonstrate that magnetic fields up to the tesla range can be applied, fulfilling a fundamental condition for the study of small spin systems. As a proof-of-principle we present the successful deposition of a Fe-filled carbon nanotube (∝ 40 nm in diameter and ∝ 14 μm in length) and an individual Co nanopillar (base diameter of ∝ 50 nm and height ∝ 10 nm) close to the nanoSQUID loop. We show that sub-micrometric control over the particle position lead to large magnetic coupling factors between the nano-loop and the spin system. Together with the possibility of applying large magnetic fields, the latter has allowed us to directly observe the magnetization reversal of these spin systems at different temperatures.

  5. Variability of Suitable Habitat of Western Winter-Spring Cohort for Neon Flying Squid in the Northwest Pacific under Anomalous Environments.

    Directory of Open Access Journals (Sweden)

    Wei Yu

    Full Text Available We developed a habitat suitability index (HSI model to evaluate the variability of suitable habitat for neon flying squid (Ommastrephes bartramii under anomalous environments in the Northwest Pacific Ocean. Commercial fisheries data from the Chinese squid-jigging vessels on the traditional fishing ground bounded by 35°-45°N and 150°-175°E from July to November during 1998-2009 were used for analyses, as well as the environmental variables including sea surface temperature (SST, chlorophyll-a (Chl-a concentration, sea surface height anomaly (SSHA and sea surface salinity (SSS. Two empirical HSI models (arithmetic mean model, AMM; geometric mean model, GMM were established according to the frequency distribution of fishing efforts. The AMM model was found to perform better than the GMM model. The AMM-based HSI model was further validated by the fishery and environmental data in 2010. The predicted HSI values in 1998 (high catch, 2008 (average catch and 2009 (low catch indicated that the squid habitat quality was strongly associated with the ENSO-induced variability in the oceanic conditions on the fishing ground. The La Niña events in 1998 tended to yield warm SST and favorable range of Chl-a concentration and SSHA, resulting in high-quality habitats for O. bartramii. While the fishing ground in the El Niño year of 2009 experienced anomalous cool waters and unfavorable range of Chl-a concentration and SSHA, leading to relatively low-quality squid habitats. Our findings suggest that the La Niña event in 1998 tended to result in more favorable habitats for O. bartramii in the Northwest Pacific with the gravity centers of fishing efforts falling within the defined suitable habitat and yielding high squid catch; whereas the El Niño event in 2009 yielded less favorable habitat areas with the fishing effort distribution mismatching the suitable habitat and a dramatic decline of the catch of O. bartramii. This study might provide some potentially

  6. Thermodynamic analysis of the squid mantle muscles and giant axon during slow swimming and jet escape propulsion

    International Nuclear Information System (INIS)

    Yalçınkaya, Bahar Hazal; Erikli, Şükrü; Özilgen, Burak Arda; Olcay, Ali Bahadır; Sorgüven, Esra; Özilgen, Mustafa

    2016-01-01

    Squids have two substantially different types of muscle fibers: superficial mitochondria rich fibers, which perform aerobic respiration during slow swimming, and central mitochondria poor fibers, which perform anaerobic respiration during jet escape. A detailed thermodynamic analysis shows that during slow swimming, 3.82 J/(kg s) of chemical exergy is consumed, and a total muscle work of 0.28 J/(kg s) is produced. 0.27 J/(kg s) of this is produced by the fin to generate lift, and the rest by the mantle volume contraction. During the jet escape at a speed of 3 mantle length/s, squid consumes an exergy of 9.97 J/(kg s) and produces a muscle work of 0.16 J/(kg s). Exergy destruction rates during slow swimming and jet escape modes are 3.54 and 9.81 J/(kg s), respectively. Exergy destroyed because of the action potential propagation in the squid giant axon is calculated as 0.03 and 0.10 J/(kg s) for the slow and fast swimming modes, respectively. - Highlights: • Slow and fast swimming modes of a squid is thermodynamically analyzed. • As swimming speed increases, respiration mode switches from aerobic to anaerobic, and respiration efficiency decreases. • During fast swimming ca. 2.6 times more chemical exergy is consumed. • Both muscles and giant axon destroy nearly 3 times more exergy during jet escape. • Contraction efficiency decreases from 36.8% to 4.7% as the volume of the passive tissue increases from 5% to 95%.

  7. Limits to the observation of coherent oscillations in a SQUID ring

    International Nuclear Information System (INIS)

    Diggins, J.

    1995-01-01

    Using the quantum mechanical, lumped component model of a SQUID ring we compute the onset of tunnelling and macroscopic superposition behaviour in the parameter space of the ring. In addition, we make a quantitative estimate of the stability required in the environmental flux to sustain a superposition state. Both these features are of crucial importance to the realisation of experiments aimed at revealing such behaviour. (orig.)

  8. Projected near-future CO2 levels increase activity and alter defensive behaviours in the tropical squid Idiosepius pygmaeus

    Directory of Open Access Journals (Sweden)

    Blake L. Spady

    2014-10-01

    Full Text Available Carbon dioxide (CO2 levels projected to occur in the oceans by the end of this century cause a range of behavioural effects in fish, but whether other highly active marine organisms, such as cephalopods, are similarly affected is unknown. We tested the effects of projected future CO2 levels (626 and 956 µatm on the behaviour of male two-toned pygmy squid, Idiosepius pygmaeus. Exposure to elevated CO2 increased the number of active individuals by 19–25% and increased movement (number of line-crosses by nearly 3 times compared to squid at present-day CO2. Squid vigilance and defensive behaviours were also altered by elevated CO2 with >80% of individuals choosing jet escape responses over defensive arm postures in response to a visual startle stimulus, compared with 50% choosing jet escape responses at control CO2. In addition, more escape responses were chosen over threat behaviours in body pattern displays at elevated CO2 and individuals were more than twice as likely to use ink as a defence strategy at 956 µatm CO2, compared with controls. Increased activity could lead to adverse effects on energy budgets as well as increasing visibility to predators. A tendency to respond to a stimulus with escape behaviours could increase survival, but may also be energetically costly and could potentially lead to more chases by predators compared with individuals that use defensive postures. These results demonstrate that projected future ocean acidification affects the behaviours of a tropical squid species.

  9. Extraction and characterization of collagen from Antarctic and Sub-Antarctic squid and its potential application in hybrid scaffolds for tissue engineering.

    Science.gov (United States)

    Coelho, Rui C G; Marques, Ana L P; Oliveira, Sara M; Diogo, Gabriela S; Pirraco, Rogério P; Moreira-Silva, Joana; Xavier, José C; Reis, Rui L; Silva, Tiago H; Mano, João F

    2017-09-01

    Collagen is the most abundant protein found in mammals and it exhibits a low immunogenicity, high biocompatibility and biodegradability when compared with others natural polymers. For this reason, it has been explored for the development of biologically instructive biomaterials with applications for tissue substitution and regeneration. Marine origin collagen has been pursued as an alternative to the more common bovine and porcine origins. This study focused on squid (Teuthoidea: Cephalopoda), particularly the Antarctic squid Kondakovia longimana and the Sub-Antarctic squid Illex argentinus as potential collagen sources. In this study, collagen has been isolated from the skins of the squids using acid-based and pepsin-based protocols, with the higher yield being obtained from I. argentinus in the presence of pepsin. The produced collagen has been characterized in terms of physicochemical properties, evidencing an amino acid profile similar to the one of calf collagen, but exhibiting a less preserved structure, with hydrolyzed portions and a lower melting temperature. Pepsin-soluble collagen isolated from I. argentinus was selected for further evaluation of biomedical potential, exploring its incorporation on poly-ε-caprolactone (PCL) 3D printed scaffolds for the development of hybrid scaffolds for tissue engineering, exhibiting hierarchical features. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. NOAA ESRI Geotiff- 1m Multibeam Bathymetry of NPS's Virgin Islands Coral Reef National Monument (Inshore), St. John, US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Geotiff with 1 meter cell size representing the bathymetry of an inshore portion of the NPS's Virgin Islands Coral Reef National...

  11. 76 FR 66260 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-10-26

    ...) of scup, 184,280 lb (83,588 kg) of black sea bass, and 200,000 lb (90,718 kg) of bluefish. Project... summer flounder, scup, black sea bass, longfin squid, butterfish, and Atlantic bluefish, and assessment...

  12. Dimorphic ejaculates and sperm release strategies associated with alternative mating behaviors in the squid.

    Science.gov (United States)

    Apostólico, Lígia H; Marian, José E A R

    2017-11-01

    Sperm competition is a powerful postcopulatory selective force influencing male adaptations associated with increasing fertilization success, and it is usually related to the evolution of different strategies of ejaculate expenditure between individuals. Ejaculates may also be influenced by additional selective pressures associated with sperm competition, such as timing between insemination and fertilization, female reproductive tract morphology, and fertilization environment. Also, males that adopt alternative mating tactics may face distinct sperm competition pressures, which may lead to the evolution of intraspecific diversity in ejaculates. In loliginid squids, males with alternative reproductive tactics (sneakers and consorts) differ not only in mating behavior, but also transfer spermatophores into two distinct sites within the female. Here, we compared structure and functioning of spermatophores between sneakers and consorts in the squid Doryteuthis plei applying microscopy techniques and in vitro experiments. Sneakers and consorts exhibit differences in spermatophore structure that lead to distinct spermatophoric reactions and spermatangium morphologies. Moreover, in sneakers, sperm release lasts longer and their sperm show an aggregative behavior not detected in consorts. Slow sperm release may be a strategy to guarantee longer sperm provision, given the wide interval between sneaker mating and egg release. For consorts, in turn, intense and quick sperm discharge may be advantageous, as timing between mating and egg-laying is relatively short. Within the complex squid mating system, factors such as (i) different fertilization sites and (ii) interval between mating and egg release may also influence sperm competition, and ultimately shape the evolution of divergent ejaculates between dimorphic males. © 2017 Wiley Periodicals, Inc.

  13. Digitally controlled high-performance dc SQUID readout electronics for a 304-channel vector magnetometer

    Science.gov (United States)

    Bechstein, S.; Petsche, F.; Scheiner, M.; Drung, D.; Thiel, F.; Schnabel, A.; Schurig, Th

    2006-06-01

    Recently, we have developed a family of dc superconducting quantum interference device (SQUID) readout electronics for several applications. These electronics comprise a low-noise preamplifier followed by an integrator, and an analog SQUID bias circuit. A highly-compact low-power version with a flux-locked loop bandwidth of 0.3 MHz and a white noise level of 1 nV/√Hz was specially designed for a 304-channel low-Tc dc SQUID vector magnetometer, intended to operate in the new Berlin Magnetically Shielded Room (BMSR-2). In order to minimize the space needed to mount the electronics on top of the dewar and to minimize the power consumption, we have integrated four electronics channels on one 3 cm × 10 cm sized board. Furthermore we embedded the analog components of these four channels into a digitally controlled system including an in-system programmable microcontroller. Four of these integrated boards were combined to one module with a size of 4 cm × 4 cm × 16 cm. 19 of these modules were implemented, resulting in a total power consumption of about 61 W. To initialize the 304 channels and to service the system we have developed software tools running on a laptop computer. By means of these software tools the microcontrollers are fed with all required data such as the working points, the characteristic parameters of the sensors (noise, voltage swing), or the sensor position inside of the vector magnetometer system. In this paper, the developed electronics including the software tools are described, and first results are presented.

  14. A novel squid pen chitosan/hydroxyapatite/β-tricalcium phosphate composite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Shavandi, Amin, E-mail: amin.shavandi@postgrad.otago.ac.nz [Department of Food Sciences, University of Otago, Dunedin (New Zealand); Department of Applied Sciences, University of Otago, Dunedin (New Zealand); Bekhit, Alaa El-Din A. [Department of Food Sciences, University of Otago, Dunedin (New Zealand); Sun, Zhifa; Ali, Azam [Department of Physics, University of Otago, Dunedin (New Zealand); Gould, Maree [Department of Anatomy, University of Otago, Dunedin (New Zealand)

    2015-10-01

    Squid pen chitosan was used in the fabrication of biocomposite scaffolds for bone tissue engineering. Hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) obtained from waste mussel shells were used as the calcium phosphate source. The composite was prepared using 2.5% tripolyphosphate (TPP) and 1% glycerol as a cross-linker and plasticizer, respectively. The weight percent (wt.%) ratios of the ceramic components in the composite were 20/10/70, 30/20/50 and 40/30/30 (HA/β-TCP/Chi). The biodegradation rate and structural properties of the scaffolds were investigated. Scanning electron microscopy (SEM) and microCT(μCT) results indicated that the composites have a well defined lamellar structure with an average pore size of 200 μm. The porosity of the composites decreased from 88 to 56% by increasing the ratio of HA/β-TCP from 30 to 70%. After 28 days of incubation in a physiological solution, the scaffolds were degraded by approximately 30%. In vitro investigations showed that the composites were cytocompatible and supported the growth of L929 and Saos-2 cells. The obtained data suggests that the squid pen chitosan composites are potential candidates for bone regeneration. - Highlights: • Biocomposite scaffolds were made from mussel shells HA and β-TCP, and squid pin chitosan. • The porosity of the composites decreased with an increase in HA/β-TCP ratio. • Composites were cytocompatible and supported the growth of L929 and Saos-2 cells. • Composite containing 50% HA and β-TCP had the best mechanical properties.

  15. Bacterial bioluminescence regulates expression of a host cryptochrome gene in the squid-Vibrio symbiosis.

    Science.gov (United States)

    Heath-Heckman, Elizabeth A C; Peyer, Suzanne M; Whistler, Cheryl A; Apicella, Michael A; Goldman, William E; McFall-Ngai, Margaret J

    2013-04-02

    The symbiosis between the squid Euprymna scolopes and its luminous symbiont, Vibrio fischeri, is characterized by daily transcriptional rhythms in both partners and daily fluctuations in symbiont luminescence. In this study, we sought to determine whether symbionts affect host transcriptional rhythms. We identified two transcripts in host tissues (E. scolopes cry1 [escry1] and escry2) that encode cryptochromes, proteins that influence circadian rhythms in other systems. Both genes cycled daily in the head of the squid, with a pattern similar to that of other animals, in which expression of certain cry genes is entrained by environmental light. In contrast, escry1 expression cycled in the symbiont-colonized light organ with 8-fold upregulation coincident with the rhythms of bacterial luminescence, which are offset from the day/night light regime. Colonization of the juvenile light organ by symbionts was required for induction of escry1 cycling. Further, analysis with a mutant strain defective in light production showed that symbiont luminescence is essential for cycling of escry1; this defect could be complemented by presentation of exogenous blue light. However, blue-light exposure alone did not induce cycling in nonsymbiotic animals, but addition of molecules of the symbiont cell envelope to light-exposed animals did recover significant cycling activity, showing that light acts in synergy with other symbiont features to induce cycling. While symbiont luminescence may be a character specific to rhythms of the squid-vibrio association, resident microbial partners could similarly influence well-documented daily rhythms in other systems, such as the mammalian gut.

  16. Digitally controlled high-performance dc SQUID readout electronics for a 304-channel vector magnetometer

    International Nuclear Information System (INIS)

    Bechstein, S; Petsche, F; Scheiner, M; Drung, D; Thiel, F; Schnabel, A; Schurig, Th

    2006-01-01

    Recently, we have developed a family of dc superconducting quantum interference device (SQUID) readout electronics for several applications. These electronics comprise a low-noise preamplifier followed by an integrator, and an analog SQUID bias circuit. A highly-compact low-power version with a flux-locked loop bandwidth of 0.3 MHz and a white noise level of 1 nV/√Hz was specially designed for a 304-channel low-T c dc SQUID vector magnetometer, intended to operate in the new Berlin Magnetically Shielded Room (BMSR-2). In order to minimize the space needed to mount the electronics on top of the dewar and to minimize the power consumption, we have integrated four electronics channels on one 3 cm x 10 cm sized board. Furthermore we embedded the analog components of these four channels into a digitally controlled system including an in-system programmable microcontroller. Four of these integrated boards were combined to one module with a size of 4 cm x 4 cm x 16 cm. 19 of these modules were implemented, resulting in a total power consumption of about 61 W. To initialize the 304 channels and to service the system we have developed software tools running on a laptop computer. By means of these software tools the microcontrollers are fed with all required data such as the working points, the characteristic parameters of the sensors (noise, voltage swing), or the sensor position inside of the vector magnetometer system. In this paper, the developed electronics including the software tools are described, and first results are presented

  17. Digitally controlled high-performance dc SQUID readout electronics for a 304-channel vector magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Bechstein, S [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Petsche, F [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Scheiner, M [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Drung, D [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Thiel, F [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Schnabel, A [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Schurig, Th [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany)

    2006-06-01

    Recently, we have developed a family of dc superconducting quantum interference device (SQUID) readout electronics for several applications. These electronics comprise a low-noise preamplifier followed by an integrator, and an analog SQUID bias circuit. A highly-compact low-power version with a flux-locked loop bandwidth of 0.3 MHz and a white noise level of 1 nV/{radical}Hz was specially designed for a 304-channel low-T{sub c} dc SQUID vector magnetometer, intended to operate in the new Berlin Magnetically Shielded Room (BMSR-2). In order to minimize the space needed to mount the electronics on top of the dewar and to minimize the power consumption, we have integrated four electronics channels on one 3 cm x 10 cm sized board. Furthermore we embedded the analog components of these four channels into a digitally controlled system including an in-system programmable microcontroller. Four of these integrated boards were combined to one module with a size of 4 cm x 4 cm x 16 cm. 19 of these modules were implemented, resulting in a total power consumption of about 61 W. To initialize the 304 channels and to service the system we have developed software tools running on a laptop computer. By means of these software tools the microcontrollers are fed with all required data such as the working points, the characteristic parameters of the sensors (noise, voltage swing), or the sensor position inside of the vector magnetometer system. In this paper, the developed electronics including the software tools are described, and first results are presented.

  18. Site-specific variation in gene expression from Symbiodinium spp. associated with offshore and inshore Porites astreoides in the lower Florida Keys is lost with bleaching and disease stress.

    Directory of Open Access Journals (Sweden)

    Briana Hauff Salas

    Full Text Available Scleractinian coral are experiencing unprecedented rates of mortality due to increases in sea surface temperatures in response to global climate change. Some coral species however, survive high temperature events due to a reduced susceptibility to bleaching. We investigated the relationship between bleaching susceptibility and expression of five metabolically related genes of Symbiodinium spp. from the coral Porites astreoides originating from an inshore and offshore reef in the Florida Keys. The acclimatization potential of Symbiodinium spp. to changing temperature regimes was also measured via a two-year reciprocal transplant between the sites. Offshore coral fragments displayed significantly higher expression in Symbiodinium spp. genes PCNA, SCP2, G3PDH, PCP and psaE than their inshore counterparts (p<0.05, a pattern consistent with increased bleaching susceptibility in offshore corals. Additionally, gene expression patterns in Symbiodinium spp. from site of origin were conserved throughout the two-year reciprocal transplant, indicating acclimatization did not occur within this multi-season time frame. Further, laboratory experiments were used to investigate the influence of acute high temperature (32°C for eight hours and disease (lipopolysaccharide of Serratia marcescens on the five metabolically related symbiont genes from the same offshore and inshore P. astreoides fragments. Gene expression did not differ between reef fragments, or as a consequence of acute exposure to heat or heat and disease, contrasting to results found in the field. Gene expression reported here indicates functional variation in populations of Symbiodinium spp. associated with P. astreoides in the Florida Keys, and is likely a result of localized adaptation. However, gene expression patterns observed in the lab imply that functional variation in zooxanthellae observed under conditions of chronic moderate stress is lost under the acute extreme conditions studied here.

  19. Growth and flagellation of Vibrio fischeri during initiation of the sepiolid squid light organ symbiosis.

    Science.gov (United States)

    Ruby, E G; Asato, L M

    1993-01-01

    A pure culture of the luminous bacterium Vibrio fischeri is maintained in the light-emitting organ of the sepiolid squid Euprymna scolopes. When the juvenile squid emerges from its egg it is symbiont-free and, because bioluminescence is part of an anti-predatory behavior, therefore must obtain a bacterial inoculum from the surrounding environment. We document here the kinetics of the process by which newly hatched juvenile squids become infected by symbiosis-competent V. fischeri. When placed in seawater containing as few as 240 colony-forming-units (CFU) per ml, the juvenile became detectably bioluminescent within a few hours. Colonization of the nascent light organ was initiated with as few as 1 to 10 bacteria, which rapidly began to grow at an exponential rate until they reached a population size of approximately 10(5) cells by 12 h after the initial infection. Subsequently, the number of bacteria in the established symbiosis was maintained essentially constant by a combination of both a > 20-fold reduction in bacterial growth rate, and an expulsion of excess bacteria into the surrounding seawater. While V. fischeri cells are normally flagellated and motile, these bacteria did not elaborate these appendages once the symbiosis was established; however, they quickly began to synthesize flagella when they were removed from the light organ environment. Thus, two important biological characteristics, growth rate and flagellation, were modulated during establishment of the association, perhaps as part of a coordinated series of symbiotic responses.

  20. Chitinolytic Bacteria-Assisted Conversion of Squid Pen and Its Effect on Dyes and Pigments Adsorption

    Directory of Open Access Journals (Sweden)

    Tzu-Wen Liang

    2015-07-01

    Full Text Available The aim of this work was to produce chitosanase by fermenting from squid pen, and recover the fermented squid pen for dye removal by adsorption. One chitosanase induced from squid pen powder (SPP-containing medium by Bacillus cereus TKU034 was purified in high purification fold (441 and high yield of activity recovery (51% by ammonium sulfate precipitation and combined column chromatography. The SDS-PAGE results showed its molecular mass to be around 43 kDa. The TKU034 chitosanase used for the chitooligomers preparation was studied. The enzyme products revealed that the chitosanase could degrade chitosan with various degrees of polymerization, ranging from 3 to 9, as well as the chitosanase in an endolytic manner. Besides, the fermented SPP was recovered and displayed a better adsorption rate (up to 99.5% for the disperse dyes (red, yellow, blue, and black than the water-soluble food colorants, Allura Red AC (R40 and Tartrazine (Y4. The adsorbed R40 on the unfermented SPP and the fermented SPP was eluted by distilled water and 1 M NaOH to confirm the dye adsorption mechanism. The fermented SPP had a slightly higher adsorption capacity than the unfermented, and elution of the dye from the fermented SPP was easier than from the unfermented. The main dye adsorption mechanism of fermented SPP was physical adsorption, while the adsorption mechanism of unfermented SPP was chemical adsorption.

  1. Chitinolytic Bacteria-Assisted Conversion of Squid Pen and Its Effect on Dyes and Pigments Adsorption.

    Science.gov (United States)

    Liang, Tzu-Wen; Lo, Bo-Chang; Wang, San-Lang

    2015-07-23

    The aim of this work was to produce chitosanase by fermenting from squid pen, and recover the fermented squid pen for dye removal by adsorption. One chitosanase induced from squid pen powder (SPP)-containing medium by Bacillus cereus TKU034 was purified in high purification fold (441) and high yield of activity recovery (51%) by ammonium sulfate precipitation and combined column chromatography. The SDS-PAGE results showed its molecular mass to be around 43 kDa. The TKU034 chitosanase used for the chitooligomers preparation was studied. The enzyme products revealed that the chitosanase could degrade chitosan with various degrees of polymerization, ranging from 3 to 9, as well as the chitosanase in an endolytic manner. Besides, the fermented SPP was recovered and displayed a better adsorption rate (up to 99.5%) for the disperse dyes (red, yellow, blue, and black) than the water-soluble food colorants, Allura Red AC (R40) and Tartrazine (Y4). The adsorbed R40 on the unfermented SPP and the fermented SPP was eluted by distilled water and 1 M NaOH to confirm the dye adsorption mechanism. The fermented SPP had a slightly higher adsorption capacity than the unfermented, and elution of the dye from the fermented SPP was easier than from the unfermented. The main dye adsorption mechanism of fermented SPP was physical adsorption, while the adsorption mechanism of unfermented SPP was chemical adsorption.

  2. Chitinolytic Bacteria-Assisted Conversion of Squid Pen and Its Effect on Dyes and Pigments Adsorption

    Science.gov (United States)

    Liang, Tzu-Wen; Lo, Bo-Chang; Wang, San-Lang

    2015-01-01

    The aim of this work was to produce chitosanase by fermenting from squid pen, and recover the fermented squid pen for dye removal by adsorption. One chitosanase induced from squid pen powder (SPP)-containing medium by Bacillus cereus TKU034 was purified in high purification fold (441) and high yield of activity recovery (51%) by ammonium sulfate precipitation and combined column chromatography. The SDS-PAGE results showed its molecular mass to be around 43 kDa. The TKU034 chitosanase used for the chitooligomers preparation was studied. The enzyme products revealed that the chitosanase could degrade chitosan with various degrees of polymerization, ranging from 3 to 9, as well as the chitosanase in an endolytic manner. Besides, the fermented SPP was recovered and displayed a better adsorption rate (up to 99.5%) for the disperse dyes (red, yellow, blue, and black) than the water-soluble food colorants, Allura Red AC (R40) and Tartrazine (Y4). The adsorbed R40 on the unfermented SPP and the fermented SPP was eluted by distilled water and 1 M NaOH to confirm the dye adsorption mechanism. The fermented SPP had a slightly higher adsorption capacity than the unfermented, and elution of the dye from the fermented SPP was easier than from the unfermented. The main dye adsorption mechanism of fermented SPP was physical adsorption, while the adsorption mechanism of unfermented SPP was chemical adsorption. PMID:26213948

  3. Enhancements to a Superconducting Quantum Interference Device (SQUID) Multiplexer Readout and Control System

    Science.gov (United States)

    Forgione, J.; Benford, D. J.; Buchanan, E. D.; Moseley, S. H.; Rebar, J.; Shafer, R. A.

    2004-01-01

    Far-infrared detector arrays such as the 16x32 superconducting bolometer array for the SAFIRE instrument (flying on the SOFIA airborne observatory) require systems of readout and control electronics to provide translation between a user-driven, digital PC and the cold, analog world of the cryogenic detector. In 2001, the National Institute of Standards and Technology (NIST) developed their Mark III electronics for purposes of control and readout of their 1x32 SQUID Multiplexer chips. We at NASA s Goddard Space Flight Center acquired a Mark 111 system and subsequently designed upgrades to suit our and our collaborators purposes. We developed an arbitrary, programmable multiplexing system that allows the user to cycle through rows in a SQUID array in an infinite number of combinations. We provided hooks in the Mark III system to allow readout of signals from outside the Mark 111 system, such as telescope status information. Finally, we augmented the heart of the system with a new feedback algorithm implementation, flexible diagnostic tools, and informative telemetry.

  4. Depressed light emission by symbiotic Vibrio fischeri of the sepiolid squid Euprymna scolopes.

    Science.gov (United States)

    Boettcher, K J; Ruby, E G

    1990-07-01

    Bioluminescent marine bacteria of the species Vibrio fischeri are the specific light organ symbionts of the sepiolid squid Euprymna scolopes. Although they share morphological and physiological characteristics with other strains of V. fischeri, when cultured away from the light organ association the E. scolopes symbionts depress their maximal luminescence over 1,000-fold. The primary cause of this reduced luminescence is the underproduction by these bacteria of luciferase autoinducer, a molecule involved in the positive transcriptional regulation of the V. fischeri lux operon. Such an absence of visible light production outside of the symbiotic association has not been previously reported among light organ symbionts of this or any other species of luminous bacteria. Levels of luminescence approaching those of the E. scolopes bacteria in the intact association can be restored by the addition of exogenous autoinducer to bacteria in laboratory culture and are affected by the presence of cyclic AMP. We conclude that some condition(s) specific to the internal environment of the light organ is necessary for maximal autoinduction of luminescence in the symbionts of this squid-bacterial association.

  5. Detection of Rapid Atrial Arrhythmias in SQUID Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Woong; Kwon, Hyuk Chan; Kim, Ki Dam; Lee, Yong Ho; Kim, Jin Mok; Kim, In Seon; Lim, Hyun Kyoon; Park, Yong Ki [Biomagnetism Research, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kim, Doo Sang [Seoul Veterans Hospital, Seoul (Korea, Republic of); Lim, Seung Pyung [Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2005-10-15

    We propose a method to measure atrial arrhythmias (AA) such as atrial fibrillation (Afb) and atrial flutter (Afl) with a SQUID magnetocardiograph (MCG) system. To detect AA is one of challenging topics in MCG. As the AA generally have irregular rhythm and atrio-ventricular conduction, the MCG signal cannot be improved by QRS averaging; therefore a SQUID MCG system having a high SNR is required to measure informative atrial excitation with a single scan. In the case of Afb, diminished f waves are much smaller than normal P waves because the sources are usually located on the posterior wall of the heart. In this study, we utilize an MCG system measuring tangential field components, which is known to be more sensitive to a deeper current source. The average noise spectral density of the whole system in a magnetic shielded room was 10 fT/Hz(a) 1 Hz and 5 fT/Hz(a) 100 Hz. We measured the MCG signals of patients with chronic Afb and Afl. Before the AA measurement, the comparison between the measurements in supine and prone positions for P waves has been conducted and the experiment gave a result that the supine position is more suitable to measure the atrial excitation. Therefore, the AA was measured in subject's supine position. Clinical potential of AA measurement in MCG is to find an aspect of a reentry circuit and to localize the abnormal stimulation noninvasively. To give useful information about the abnormal excitation, we have developed a method, separative synthetic aperture magnetometry (sSAM). The basic idea of sSAM is to visualize current source distribution corresponding to the atrial excitation, which are separated from the ventricular excitation and the Gaussian sensor noises. By using sSAM, we localized the source of an Afl successfully.

  6. Magnetic properties of thin Ni films measured by a dc SQUID-based magnetic microscope

    DEFF Research Database (Denmark)

    Snigirev, O.V.; Andreev, K.E.; Tishin, A.M.

    1997-01-01

    We have applied a scanning HTS (high-temperature superconductor) de SQUID (superconducting quantum interference device) -based magnetic microscope to study the magnetic properties of Au/Ni/Si(100) films in the thickness range from 8 to 200 Angstrom at T = 77 K. A one-domain structure with in...

  7. Natural waste materials containing chitin as adsorbents for textile dyestuffs: batch and continuous studies.

    Science.gov (United States)

    Figueiredo, S A; Loureiro, J M; Boaventura, R A

    2005-10-01

    In this work three natural waste materials containing chitin were used as adsorbents for textile dyestuffs, namely the Anodonta (Anodonta cygnea) shell, the Sepia (Sepia officinalis) and the Squid (Loligo vulgaris) pens. The selected dyestuffs were the Cibacron green T3G-E (CI reactive green 12), and the Solophenyl green BLE 155% (CI direct green 26), both from CIBA, commonly used in cellulosic fibres dyeing, the most used fibres in the textile industry. Batch equilibrium studies showed that the materials' adsorption capacities increase after a simple and inexpensive chemical treatment, which increases their porosity and chitin relative content. Kinetic studies suggested the existence of a high internal resistance in both systems. Fixed bed column experiments performed showed an improvement in adsorbents' behaviour after chemical treatment. However, in the column experiments, the biodegradation was the main mechanism of dyestuff removal, allowing the materials' bioregeneration. The adsorption was strongly reduced by the pore clogging effect of the biomass. The deproteinised Squid pen (grain size 0.500-1.41 mm) is the adsorbent with highest adsorption capacity (0.27 and 0.037 g/g, respectively, for the reactive and direct dyestuffs, at 20 degrees C), followed by the demineralised Sepia pen and Anodonta shell, behaving like pure chitin in all experiments, but showing inferior performances than the granular activated carbon tested in the column experiments.

  8. Magnetic imaging of unconventional superconductors by scanning SQUID microscopy

    International Nuclear Information System (INIS)

    Hykel, D.

    2011-01-01

    We present the development of a scanning SQUID/AFM microscope and measurements performed on different samples. The microscope can take topographic and magnetic images simultaneously. The magnetic resolution is of the order of 10 -4 Φ 0 √Hz and the spatial resolution of the SQUIDs used in this thesis goes up to 600 nm. The scanning range is 70 μm * 85 μm. The temperature range accessible is between 200 mK and 10 K at the time of writing. Measurements on a thin rhenium film (80 nm) give an estimate of the minimal pinning force of a vortex of about 3.9 * 10 -16 N. Furthermore, the penetration depth λ on this sample was determined as a function of temperature. For T → 0, λ →79 nm. We have for the first time shown local measurements of the domain structure of the superconducting ferromagnet UCoGe and determined the average domain size in the virgin state (10 μm). By magnetic imaging we were capable of determining the magnetic field difference above opposite domains along the c-axis to be 45 G and 16 G along the b-axis. Due to these magnetic field measurements we were able to give an upper limit for the domain wall width (∼ 1μm) and domain reconstruction depth (100 nm). This is supported by simple calculations leading to a domain wall width of several angstroms. Thus UCoGe can be considered an ideal Ising ferromagnet. Different possible domain structures for an Ising ferromagnet have been discussed. The complicated domain structure found in the zero field cooled virgin state corresponds to up domains embedded in larger down domains and vice versa. We have shown evidence for coexistence of superconductivity and ferromagnetism. The weak Meissner effect can be explained by a spontaneous vortex state, put forward by other groups. Numerical simulations suggest that the strong magnetic background signal and the limited spatial and magnetic resolution of the used SQUID made it difficult to resolve the expected spontaneous vortex state. The relaxation of the

  9. Nuclear magnetic resonance with dc SQUID [Super-conducting QUantum Interference Device] preamplifiers

    International Nuclear Information System (INIS)

    Fan, N.Q.; Heaney, M.B.; Clark, J.; Newitt, D.; Wald, L.; Hahn, E.L.; Bierlecki, A.; Pines, A.

    1988-08-01

    Sensitive radio-frequency (rf) amplifiers based on dc Superconducting QUantum Interface Devices (SQUIDS) are available for frequencies up to 200 MHz. At 4.2 K, the gain and noise temperature of a typical tuned amplifier are 18.6 +- 0.5 dB and 1.7 +- 0.5 K at 93 MHz. These amplifiers are being applied to a series of novel experiments on nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR). The high sensitivity of these amplifiers was demonstrated in the observation of ''nuclear spin noise'', the emission of photons by 35 Cl nuclei in a state of zero polarization. In the more conventional experiments in which one applies a large rf pulse to the spins, a Q-spoiler, consisting of a series array of Josephson junctions, is used to reduce the Q of the input circuit to a very low value during the pulse. The Q-spoiler enables the circuit to recover quickly after the pulse, and has been used in an NQR experiment to achieve a sensitivity of about 2 /times/ 10 16 nuclear Bohr magnetons in a single free precession signal with a bandwidth of 10 kHz. In a third experiment, a sample containing 35 Cl nuclei was placed in a capacitor and the signal detected electrically using a tuned SQUID amplifier and Q-spoiler. In this way, the electrical polarization induced by the precessing Cl nuclear quadrupole moments was detected: this is the inverse of the Stark effect in NQR. Two experiments involving NMR have been carried out. In the first, the 30 MHz resonance in 119 Sn nuclei is detected with a tuned amplifier and Q-spoiler, and a single pulse resolution of 10 18 nuclear Bohr magnetons in a bandwidth of 25 kHz has been achieved. For the second, a low frequency NMR system has been developed that uses an untuned input circuit coupled to the SQUID. The resonance in 195 Pt nuclei has been observed at 55 kHz in a field of 60 gauss. 23 refs., 11 figs

  10. Detection and quantification of Vibrio fischeri autoinducer from symbiotic squid light organs.

    Science.gov (United States)

    Boettcher, K J; Ruby, E G

    1995-02-01

    Vibrio fischeri is the specific light organ symbiont of the sepiolid squid species Euprymna scolopes and Euprymna morsei. Both species of squid are luminescent by virtue of their bacterial symbionts, but the natural symbionts of E. scolopes do not produce visible luminescence in laboratory culture. The primary cause of this depressed luminescence by E. scolopes symbionts in culture was found to be the production of relatively low levels of V. fischeri autoinducer, a positive transcriptional coregulator of the lux regulon, identified as N-(3-oxohexanoyl) homoserine lactone. Concentrations of autoinducer activity produced by these symbionts in culture were quantified and found to be at least 10-fold lower than those produced by E. morsei isolates (which are visibly luminous outside the association) and perhaps 10,000-fold lower than those of the brightest V. fischeri strains. Despite the differences in their symbiont strains, the intact light organs of the two species of squid contained comparable amounts of extractable autoinducer activity (between 100 and 200 pg per adult animal). The chromatographic behavior of this autoinducer activity on reverse-phase high-performance liquid chromatography was consistent with its presumptive identification as V. fischeri autoinducer. Within the 5-microliter volume of the epithelial core of the light organ in which the symbiotic V. fischeri strains are housed, these amounts would result in an effective autoinducer concentration of at least 100 nM. Because these levels are over 40-fold higher than the concentration needed for the induction of luminescence of bacteria in culture, we conclude that the inherent degree of autoinducer production by strains of V. fischeri may not influence their effectiveness as light organ symbionts. Furthermore, this study provides the first direct evidence that the phenomenon of cell density-dependent autoinduction, discovered and described first for laboratory cultures of V. fischeri but believed to

  11. Highly balanced gradiometer systems based on HTS-SQUIDs for the use in magnetically unshielded environment

    NARCIS (Netherlands)

    Borgmann, H.J.R.; Rijpma, A.P.; ter Brake, Hermanus J.M.; Rogalla, Horst; David, P.

    1999-01-01

    Two different concepts for gradiometer formation were tested applying high-temperature rf SQUIDs operated at 77 K in liquid nitrogen. All gradiometer systems are fully based on magnetometers. The first concept applies a compensating magnetometer at different positions to actively cancel the magnetic

  12. Ocean acidification responses in paralarval squid swimming behavior using a novel 3D tracking system

    KAUST Repository

    Zakroff, Casey J.; Mooney, T. Aran; Wirth, Colin

    2017-01-01

    . pealeii from eggs reared under chronic OA demonstrated measurable impairments to swimming activity and control. This required the development of a novel, cost-effective, and robust method for 3D motion tracking and analysis. Squid eggs were reared in pCO2

  13. SQUID-magnetometry on Fe monolayers on GaAs(001) in UHV

    Energy Technology Data Exchange (ETDEWEB)

    Kebe, T

    2006-12-11

    This thesis deals with the characterization of the growth and of the magnetic properties of ultrathin Fe films on GaAs(001). In particular, a scanning SQUID (superconducting quantum interference device) magnetometer was used in ultrahigh vacuum (UHV), whose performance has been improved within the scope of this thesis. By probing the magnetic stray field of a magnetized film, the absolute remanent magnetization can be determined with submonolayer sensitivity. In the context of this thesis the magnetic stray field has been calculated analytically. The combined use of SQUID and ferromagnetic resonance (FMR) on the same film in UHV allows for the independent determination of the magnetization and the magnetic anisotropy constants as a function of temperature, film thickness, topography of the substrate and oxygen exposure. The results of this thesis are: 1. The thickness dependent remanent magnetization from 2 to 20 monolayer (ML) Fe on GaAs(001) without cap layer was measured as a function of temperature. 2. The continuous in-plane reorientation of the magnetization (from [1 1 0] to [1 0 0]) of Fe films with increasing film thickness was observed using the scanning SQUID technique and showed good agreement with FMR measurements. 3. The influence of controlled oxygen exposure on the remanent magnetization and the magnetic anisotropy constants of 5 to 16 ML Fe was investigated. A faster reduction of the magnetization is found for the thinner Fe films when the volume of the Fe oxide is taken into consideration. At low oxygen exposure (<10 Langmuir), the perpendicular uniaxial anisotropy constant K{sub 2} {sub perpendicular} {sub to} is reduced by about 40% whereas other anisotropy contributions remain virtually unchanged. In addition, structural investigations using IV-LEED during the oxygen exposure were carried out. 4. An 8.6 ML Fe/GaAs(001) film which was exposed to 25000 L O{sub 2} exhibits a spontaneous magnetization perpendicular to the film plane at low

  14. Diet and stable isotope analyses reveal the feeding ecology of the orangeback squid Sthenoteuthis pteropus (Steenstrup 1855 (Mollusca, Ommastrephidae in the eastern tropical Atlantic.

    Directory of Open Access Journals (Sweden)

    Véronique Merten

    Full Text Available In the eastern tropical Atlantic, the orangeback flying squid Sthenoteuthis pteropus (Steenstrup 1855 (Cephalopoda, Ommastrephidae is a dominant species of the epipelagic nekton community. This carnivore squid has a short lifespan and is one of the fastest-growing squids. In this study, we characterise the role of S. pteropus in the pelagic food web of the eastern tropical Atlantic by investigating its diet and the dynamics of its feeding habits throughout its ontogeny and migration. During three expeditions in the eastern tropical Atlantic in 2015, 129 specimens were caught by hand jigging. Stomach content analyses (via visual identification and DNA barcoding were combined with stable isotope data (∂15N and ∂13C of muscle tissue to describe diet, feeding habits and trophic ecology of S. pteropus. Additionally, stable isotope analyses of incremental samples along the squid's gladius-the chitinous spiniform structure supporting the muscles and organs-were carried out to explore possible diet shifts through ontogeny and migration. Our results show that S. pteropus preys mainly on myctophid fishes (e.g. Myctophum asperum, Myctophum nitidulum, Vinciguerria spp., but also on other teleost species, cephalopods (e.g. Enoploteuthidae, Bolitinidae, Ommastrephidae, crustaceans and possibly on gelatinous zooplankton as well. The squid shows a highly opportunistic feeding behaviour that includes cannibalism. Our study indicates that the trophic position of S. pteropus may increase by approximately one trophic level from a mantle length of 15 cm to 47 cm. The reconstructed isotope-based feeding chronologies of the gladii revealed high intra- and inter-individual variability in the squid's trophic position and foraging area. These findings are not revealed by diet or muscle tissue stable isotope analysis. This suggests a variable and complex life history involving individual variation and migration. The role of S. pteropus in transferring energy and

  15. Diet and stable isotope analyses reveal the feeding ecology of the orangeback squid Sthenoteuthis pteropus (Steenstrup 1855) (Mollusca, Ommastrephidae) in the eastern tropical Atlantic.

    Science.gov (United States)

    Merten, Véronique; Christiansen, Bernd; Javidpour, Jamileh; Piatkowski, Uwe; Puebla, Oscar; Gasca, Rebeca; Hoving, Henk-Jan T

    2017-01-01

    In the eastern tropical Atlantic, the orangeback flying squid Sthenoteuthis pteropus (Steenstrup 1855) (Cephalopoda, Ommastrephidae) is a dominant species of the epipelagic nekton community. This carnivore squid has a short lifespan and is one of the fastest-growing squids. In this study, we characterise the role of S. pteropus in the pelagic food web of the eastern tropical Atlantic by investigating its diet and the dynamics of its feeding habits throughout its ontogeny and migration. During three expeditions in the eastern tropical Atlantic in 2015, 129 specimens were caught by hand jigging. Stomach content analyses (via visual identification and DNA barcoding) were combined with stable isotope data (∂15N and ∂13C) of muscle tissue to describe diet, feeding habits and trophic ecology of S. pteropus. Additionally, stable isotope analyses of incremental samples along the squid's gladius-the chitinous spiniform structure supporting the muscles and organs-were carried out to explore possible diet shifts through ontogeny and migration. Our results show that S. pteropus preys mainly on myctophid fishes (e.g. Myctophum asperum, Myctophum nitidulum, Vinciguerria spp.), but also on other teleost species, cephalopods (e.g. Enoploteuthidae, Bolitinidae, Ommastrephidae), crustaceans and possibly on gelatinous zooplankton as well. The squid shows a highly opportunistic feeding behaviour that includes cannibalism. Our study indicates that the trophic position of S. pteropus may increase by approximately one trophic level from a mantle length of 15 cm to 47 cm. The reconstructed isotope-based feeding chronologies of the gladii revealed high intra- and inter-individual variability in the squid's trophic position and foraging area. These findings are not revealed by diet or muscle tissue stable isotope analysis. This suggests a variable and complex life history involving individual variation and migration. The role of S. pteropus in transferring energy and nutrients from

  16. Stable isotopes document the trophic structure of a deep-sea cephalopod assemblage including giant octopod and giant squid.

    Science.gov (United States)

    Cherel, Y; Ridoux, V; Spitz, J; Richard, P

    2009-06-23

    Although deep-sea cephalopods are key marine organims, their feeding ecology remains essentially unknown. Here, we report for the first time the trophic structure of an assemblage of these animals (19 species) by measuring the isotopic signature of wings of their lower beaks, which accumulated in stomachs of stranded sperm whales. Overall, the species encompassed a narrow range in delta(13)C values (1.7 per thousand), indicating that they lived in closely related and overlapping habitats. delta(13)C values can be interpreted in terms of distribution with the more (13)C-depleted species (e.g. Stigmatoteuthis arcturi, Vampyroteuthis infernalis) having a more pelagic habitat than the more (13)C-enriched, bathyal species (e.g. Todarodes sagittatus and the giant squid Architeuthis dux). The cephalopods sampled had delta(15)N values ranging 4.6 per thousand, which is consistent with the species spanning approximately 1.5 trophic levels. Neither the giant octopod (Haliphron atlanticus) nor the giant squid reached the highest trophic position. Species delta(15)N was independent of body size, with large squids having both the highest (Taningia danae) and lowest (Lepidoteuthis grimaldii) delta(15)N values. Their trophic position indicates that some species share the top of the food web, together with other megacarnivores such as the sperm whale.

  17. Sneaker Male Squid Produce Long-lived Spermatozoa by Modulating Their Energy Metabolism

    OpenAIRE

    Hirohashi, Noritaka; Tamura-Nakano, Miwa; Nakaya, Fumio; Iida, Tomohiro; Iwata, Yoko

    2016-01-01

    Spermatozoa released by males should remain viable until fertilization. Hence, sperm longevity is governed by intrinsic and environmental factors in accordance with the male mating strategy. However, whether intraspecific variation of insemination modes can impact sperm longevity remains to be elucidated. In the squid Heterololigo bleekeri, male dimorphism (consort and sneaker) is linked to two discontinuous insemination modes that differ in place and time. Notably, only sneaker male spermato...

  18. Morphological beak differences of loliginid squid, Uroteuthis chinensis and Uroteuthis edulis, in the northern South China Sea

    Science.gov (United States)

    Jin, Yue; Liu, Bilin; Chen, Xinjun; Staples, Kevin

    2018-03-01

    The mitre squid ( Uroteuthis chinensis) and the swordtip squid ( U. edulis) are Indo-Pacific cephalopod species that are abundant in the western Pacific Ocean. They are currently exploited in the East and South China Seas and make up a significant portion of the Chinese neritic squid catch. Beaks, the feeding organs of squid, are important for individual size and biomass estimation because of their high resistance to degradation in predator stomachs and consistent dimensions. In this study, 104 U. chinensis and 143 U. edulis individuals were sampled from northern South China Sea with mantle length from 70 to 260 mm and 96 to 284 mm, respectively. The results indicated that morphological beak values were greater for U. edulis, compared to U. chinensis, for upper hood length (UHL), upper crest length (UCL), upper lateral wall length (ULWL), lower crest length (LCL), and lower lateral wall length (LLWL). According to principal component analysis, UHL/ML, UCL/ML, ULWL/ML, LCL/ML, LLWL/ML and LWL/ML could represent the characteristics of beaks for U. chinensis, while UHL/ML, UCL/ML, ULWL/ML, LHL/ML, LCL/ML and LLWL/ML could represent it for U. edulis. According to Akaike's information criterion (AIC) values, a power function was the most suitable model for U. chinensis, while a linear function was the most suitable model for U. edulis. The beak variable-mantle length ratio (beak variable/mantle length) declined with the increasing of mantle length and declined sharply at the early stage of growth in both beaks and species. The ratio changed quickly after achieving the mantle length of 140 mm for U. chinensis, while the ratio changed quickly after 170 mm for U. edulis. Beaks in both species experienced sharper changes through maturity stage I to II than other maturity stages. This study gives us basic beak morphology information for U. chinensis and U. edulis in the East and South China Seas. Geometric morphological methods combined with dietary analysis should be used

  19. Comparison live adult Artemia and squid meat on the growth of Penaeid shrimp Metapenaeus dobsoni (Miers)

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Achuthankutty, C.T.; Royan, J.P.

    An experiment lasting 14 weeks was conducted to compare the efficiency of live adult Artemia with fresh squid meat on growth of penaeid shrimp Metapenaeus dobsoni. The shrimps were found actively feeding on live Artemia and grew 84% more than those...

  20. Induced electric currents in the Alaska oil pipeline measured by gradient, fluxgate, and SQUID magnetometers

    Science.gov (United States)

    Campbell, W. H.; Zimmerman, J. E.

    1979-01-01

    The field gradient method for observing the electric currents in the Alaska pipeline provided consistent values for both the fluxgate and SQUID method of observation. These currents were linearly related to the regularly measured electric and magnetic field changes. Determinations of pipeline current were consistent with values obtained by a direct connection, current shunt technique at a pipeline site about 9.6 km away. The gradient method has the distinct advantage of portability and buried- pipe capability. Field gradients due to the pipe magnetization, geological features, or ionospheric source currents do not seem to contribute a measurable error to such pipe current determination. The SQUID gradiometer is inherently sensitive enough to detect very small currents in a linear conductor at 10 meters, or conversely, to detect small currents of one amphere or more at relatively great distances. It is fairly straightforward to achieve imbalance less than one part in ten thousand, and with extreme care, one part in one million or better.

  1. Polarization sensitivity and retinal topography of the striped pyjama squid (Sepioloidea lineolata - Quoy/Gaimard 1832).

    Science.gov (United States)

    Talbot, Christopher M; Marshall, Justin

    2010-10-01

    Coleoid cephalopods (octopus, cuttlefish and squid) potentially possess polarization sensitivity (PS) based on photoreceptor structure, but this idea has rarely been tested behaviourally. Here, we use a polarized, striped optokinetic stimulus to demonstrate PS in the striped pyjama squid, Sepioloidea lineolata. This species displayed strong, consistent optokinetic nystagmic eye movements in response to a drum with stripes producing e-vectors set to 0 deg, 45 deg, 90 deg and 135 deg that would only be visible to an animal with PS. This is the first behavioural demonstration of a polarized optokinetic response in any species of cephalopod. This species, which typically sits beneath the substrate surface looking upwards for potential predators and prey, possesses a dorsally shifted horizontal pupil slit. Accordingly, it was found to possess a horizontal strip of high-density photoreceptors shifted ventrally in the retina, suggesting modifications such as a change in sensitivity or resolution to the dorsal visual field.

  2. NOAA TIFF Image - 1 m Backscatter Mosaic of an inshore portion of the NPS's Virgin Islands Coral Reef National Monument, south of St. John, US Virgin Islands, Project NF-05-05, 2005, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the inshore portion of the NPS's Virgin Islands Coral Reef National Monument, south of St. John, US...

  3. Multichannel DC SQUID sensor array for biomagnetic applications

    International Nuclear Information System (INIS)

    Hoenig, H.E.; Daalmans, G.M.; Bar, L.; Bommel, F.; Paulus, A.; Uhl, D.; Weisse, H.J.; Schneider, S.; Seifert, H.; Reichenberger, H.; Abraham-Fuchs, K.

    1991-01-01

    This paper reports on a biomagnetic multichannel system for medical diagnosis of brain and heart KRENIKON has been developed. 37 axial 2st order gradiometers - manufactured as flexible superconducting printed circuits - are arranged in a circular flat array of 19 cm diameter. Additionally, 3 orthogonal magnetometers are provided. The DC SQUIDs are fabricated in all-Nb technology, ten on a chip. The sensor system is operated in a shielded room with two layers of soft magnetic material and one layer of Al. The every day noise level is 10 fT/Hz 1/2 at frequencies above 10 Hz. Within 2 years of operation in a normal urban surrounding, useful clinical applications have been demonstrated (e.g. for epilepsy and heart arrhythmias)

  4. Detection of fine magnetic particles coated on a thread using an HTS-SQUID

    International Nuclear Information System (INIS)

    Kawagishi, K.; Itozaki, H.; Kondo, T.; Komori, K.; Koetitz, R.

    2004-01-01

    Polymer-coated magnetic particles, which contain superparamagnetic ferrite nanoparticles, were attached to a nylon thread of 0.35 mm in diameter and were detected by an HTS-SQUID. The length of the sample attached into the thread was within 3 mm and its interval was 30 mm. The particles were magnetized by a coil applied dc field or by a magnet of 1.4 T. The thread ran 2 mm under the SQUID with 20-100 mm/s of the rate. Signals of magnetic beads were detected and the peak-to-peak amplitude of the signals was directly proportional to the applied field and the weight of the magnetic particles. Obtained peak-to-peak amplitude for 20 ng of magnetite particles was 350 pT at 0.25 mT of applied dc field with noise of 18 pT, and estimated detection limit was 10 ng. S/N ratio was improved by the remanence measurement using the magnet and 5.8 ng of detection limit was obtained. This measurement has been proved to be promising for the continuous analysis of ultra dilute DNA solution

  5. CO2-level Dependent Effects of Ocean Acidification on Squid, Doryteuthis pealeii, Early Life History

    KAUST Repository

    Zakroff, Casey J.

    2013-12-01

    Ocean acidification is predicted to lead to global oceanic decreases in pH of up to 0.3 units within the next 100 years. However, those levels are already being reached currently in coastal regions due to natural CO2 variability. Squid are a vital component of the pelagic ecosystem, holding a unique niche as a highly active predatory invertebrate and major prey stock for upper trophic levels. This study examined the effects of a range of ocean acidification regimes on the early life history of a coastal squid species, the Atlantic longfin squid, Doryteuthis pealeii. Eggs were raised in a flow-through ocean acidification system at CO2 levels ranging from ambient (400ppm) to 2200ppm. Time to hatching, hatching efficiency, and hatchling mantle lengths, yolk sac sizes, and statoliths were all examined to elucidate stress effects. Delays in hatching time of at least a day were seen at exposures above 1300ppm in all trials under controlled conditions. Mantle lengths were significantly reduced at exposures above 1300 ppm. Yolk sac sizes varied between CO2 treatments, but no distinct pattern emerged. Statoliths were increasingly porous and malformed as CO2 exposures increased, and were significantly reduced in surface area at exposures above 1300ppm. Doryteuthis pealeii appears to be able to withstand acidosis stress without major effects up to 1300ppm, but is strongly impacted past that threshold. Since yolk consumption did not vary among treatments, it appears that during its early life stages, D. pealeii reallocates its available energy budget away from somatic growth and system development in order to mitigate the stress of acidosis.

  6. Squid pen-inspired chitinous functional materials: Hierarchical chitin fibers by centrifugal jet-spinning and transparent chitin fiber-reinforced composite

    Science.gov (United States)

    Jeong, Seung-Hwan; Kim, Joong-Kwon; Lim, Young-Woo; Hwang, Hyun-Bin; Kwon, Hee-Young; Bae, Byeong-Soo; Jin, Jungho

    2018-01-01

    Here, inspired by the fibrous composite structure of a squid pen, we introduce hierarchical chitin fibers (herein, termed "Chiber") and their transparent composites and demonstrate the potential of these chitinous functional materials as a sustainable separation-membrane and reinforcing filler for composites. We employ a centrifugal jet-spinning process to fabricate Chiber with aligned chitin nanofibrillar architectures, for which we discuss the processing-morphology relationship. A nonwoven fiber-mat made of Chiber exhibits excellent adsorbing performance for a toxic ionic dye (Congo Red), and has a low coefficient of thermal expansion comparable to that of glass fibers. Finally, we demonstrate a squid pen-mimetic transparent composite using Chiber and investigate its optical property.

  7. Effects of colonization, luminescence, and autoinducer on host transcription during development of the squid-vibrio association.

    Science.gov (United States)

    Chun, Carlene K; Troll, Joshua V; Koroleva, Irina; Brown, Bartley; Manzella, Liliana; Snir, Einat; Almabrazi, Hakeem; Scheetz, Todd E; Bonaldo, Maria de Fatima; Casavant, Thomas L; Soares, M Bento; Ruby, Edward G; McFall-Ngai, Margaret J

    2008-08-12

    The light-organ symbiosis between the squid Euprymna scolopes and the luminous bacterium Vibrio fischeri offers the opportunity to decipher the hour-by-hour events that occur during the natural colonization of an animal's epithelial surface by its microbial partners. To determine the genetic basis of these events, a glass-slide microarray was used to characterize the light-organ transcriptome of juvenile squid in response to the initiation of symbiosis. Patterns of gene expression were compared between animals not exposed to the symbiont, exposed to the wild-type symbiont, or exposed to a mutant symbiont defective in either of two key characters of this association: bacterial luminescence or autoinducer (AI) production. Hundreds of genes were differentially regulated as a result of symbiosis initiation, and a hierarchy existed in the magnitude of the host's response to three symbiont features: bacterial presence > luminescence > AI production. Putative host receptors for bacterial surface molecules known to induce squid development are up-regulated by symbiont light production, suggesting that bioluminescence plays a key role in preparing the host for bacteria-induced development. Further, because the transcriptional response of tissues exposed to AI in the natural context (i.e., with the symbionts) differed from that to AI alone, the presence of the bacteria potentiates the role of quorum signals in symbiosis. Comparison of these microarray data with those from other symbioses, such as germ-free/conventionalized mice and zebrafish, revealed a set of shared genes that may represent a core set of ancient host responses conserved throughout animal evolution.

  8. A decadal analysis of bioeroding sponge cover on the inshore Great Barrier Reef.

    Science.gov (United States)

    Ramsby, Blake D; Hoogenboom, Mia O; Whalan, Steve; Webster, Nicole S; Thompson, Angus

    2017-06-02

    Decreasing coral cover on the Great Barrier Reef (GBR) may provide opportunities for rapid growth and expansion of other taxa. The bioeroding sponges Cliona spp. are strong competitors for space and may take advantage of coral bleaching, damage, and mortality. Benthic surveys of the inshore GBR (2005-2014) revealed that the percent cover of the most abundant bioeroding sponge species, Cliona orientalis, has not increased. However, considerable variation in C. orientalis cover, and change in cover over time, was evident between survey locations. We assessed whether biotic or environmental characteristics were associated with variation in C. orientalis distribution and abundance. The proportion of fine particles in the sediments was negatively associated with the presence-absence and the percent cover of C. orientalis, indicating that the sponge requires exposed habitat. The cover of corals and other sponges explained little variation in C. orientalis cover or distribution. The fastest increases in C. orientalis cover coincided with the lowest macroalgal cover and chlorophyll a concentration, highlighting the importance of macroalgal competition and local environmental conditions for this bioeroding sponge. Given the observed distribution and habitat preferences of C. orientalis, bioeroding sponges likely represent site-specific - rather than regional - threats to corals and reef accretion.

  9. SQUID-detected magnetic resonance imaging in microtesla magnetic fields

    International Nuclear Information System (INIS)

    McDermott, Robert; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Mueck, Michael; Myers, Whittier; Haken, Bernard ten; Seton, H.C.; Trabesinger, Andreas H.; Pines, Alex; Clarke, John

    2003-01-01

    We describe studies of nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) of liquid samples at room temperature in microtesla magnetic fields. The nuclear spins are prepolarized in a strong transient field. The magnetic signals generated by the precessing spins, which range in frequency from tens of Hz to several kHz, are detected by a low-transition temperature dc SQUID (Superconducting QUantum Interference Device) coupled to an untuned, superconducting flux transformer configured as an axial gradiometer. The combination of prepolarization and frequency-independent detector sensitivity results in a high signal-to-noise ratio and high spectral resolution (∼1 Hz) even in grossly inhomogeneous magnetic fields. In the NMR experiments, the high spectral resolution enables us to detect the 10-Hz splitting of the spectrum of protons due to their scalar coupling to a 31P nucleus. Furthermore, the broadband detection scheme combined with a non-resonant field-reversal spin echo allows the simultaneous observation of signals from protons and 31P nuclei, even though their NMR resonance frequencies differ by a factor of 2.5. We extend our methodology to MRI in microtesla fields, where the high spectral resolution translates into high spatial resolution. We demonstrate two-dimensional images of a mineral oil phantom and slices of peppers, with a spatial resolution of about 1 mm. We also image an intact pepper using slice selection, again with 1-mm resolution. In further experiments we demonstrate T1-contrast imaging of a water phantom, some parts of which were doped with a paramagnetic salt to reduce the longitudinal relaxation time T1. Possible applications of this MRI technique include screening for tumors and integration with existing multichannel SQUID systems for brain imaging

  10. Operational Prediction of the Habitat Suitability Index (HSI) Distribution for Neon Flying Squid in Central North Pacific by Using FORA Dataset and a New Data Assimilation System SKUIDS

    Science.gov (United States)

    Igarashi, H.; Ishikawa, Y.; Wakamatsu, T.; Tanaka, Y.; Nishikawa, S.; Nishikawa, H.; Kamachi, M.; Kuragano, T.; Takatsuki, Y.; Fujii, Y.; Usui, N.; Toyoda, T.; Hirose, N.; Sakai, M.; Saitoh, S. I.; Imamura, Y.

    2016-02-01

    The neon flying squid (Ommastrephes bartramii) has a wide-spread distribution in subtropical and temperate waters in the North Pacific, which plays an important role in the pelagic ecosystem and is one of the major targets in Japanese squid fisheries. The main fishing areas for Japanese commercial vessels are located in the central North Pacific (35-45N, around the date line) in summer. In this study, we have developed several kinds of habitat suitability index (HSI) models of the neon flying squid for investigating the relationship between its potential habitat and the ocean state variations in the target area. For developing HSI models, we have used a new ocean reanalysis dataset FORA (4-dimensional variational Ocean Re-Analysis) produced by JAMSTEC/CEIST and MRI-JMA. The horizontal resolution is 0.1*0.1 degree of latitude and longitude with 54 vertical levels, which can provide realistic fields of 3-dimensional ocean circulation and environmental structures including meso-scale eddies. In addition, we have developed a new 4D-VAR (4-dimensional variational) ocean data assimilation system for predicting ocean environmental changes in the main fishing grounds. We call this system "SKUIDS" (Scalable Kit of Under-sea Information Delivery System). By using these prediction fields of temperature, salinity, sea surface height, horizontal current velocity, we produced daily HSI maps of the neon flying squid, and provided them to the Japanese commercial vessels in operation. Squid fishermen can access the web site for delivering the information of ocean environments in the fishing ground by using Inmarsat satellite communication on board, and show the predicted fields of subsurface temperatures and HSI. Here, we present the details of SKUIDS and the web-delivery system for squid fishery, and some preliminary results of the operational prediction.

  11. A squid-based beam current monitor for FAIR/CRYRING

    International Nuclear Information System (INIS)

    Geithner, Rene; Stöhlker, Thomas; Kurian, Febin; Reeg, Hansjörg; Schwickert, Marcus; Neubert, Ralf; Seidel, Paul

    2015-01-01

    A SQUID-based beam current monitor was developed for the upcoming FAIR-Project, providing a non-destructive online monitoring of the beam currents in the nA-range. The cryogenic current comparator (CCC) was optimized for lowest possible noise-limited current resolution together with a high system bandwidth. This CCC is foreseen to be installed in the CRYRING facility (CRYRING@ESR: A study group report www.gsi.de/fileadmin/SPARC/documents/Cryring/ReportCryring-40ESR.PDF), working as a test bench for FAIR. In this contribution we present results of the completed CCC for FAIR/CRYRING and also arrangements that have been done for the installation of the CCC at CRYRING, regarding the cryostat design. (paper)

  12. Depressed light emission by symbiotic Vibrio fischeri of the sepiolid squid Euprymna scolopes.

    OpenAIRE

    Boettcher, K J; Ruby, E G

    1990-01-01

    Bioluminescent marine bacteria of the species Vibrio fischeri are the specific light organ symbionts of the sepiolid squid Euprymna scolopes. Although they share morphological and physiological characteristics with other strains of V. fischeri, when cultured away from the light organ association the E. scolopes symbionts depress their maximal luminescence over 1,000-fold. The primary cause of this reduced luminescence is the underproduction by these bacteria of luciferase autoinducer, a molec...

  13. Magnetic characterization by SQUID and FMR of a biocompatible ferrofluid based on Fe3O4

    International Nuclear Information System (INIS)

    Gamarra, L F; Amaro Jr, E; Pontuschka, W M; Mamani, J B; Cornejo, D R; Oliveira, T R; Vieira, E D; Costa-Filho, A J

    2009-01-01

    Biocompatible superparamagnetic iron oxide nanoparticles of magnetite coated with dextran were magnetically characterized using the techniques of SQUID (superconducting quantum interference device) magnetometry and ferromagnetic resonance (FMR). The SQUID magnetometry characterization was performed by isothermal measurements under applied magnetic field using the methods of zero-field-cooling (ZFC) and field-cooling (FC). The magnetic behavior of the nanoparticles indicated their superparamagnetic nature and it was assumed that they consisted exclusively of monodomains. The transition to a blocked state was observed at the temperature T B = (43 ± 1) K for frozen ferrofluid and at (52 ± 1) K for the lyophilized ferrofluid samples. The FMR analysis showed that the derivative peak-to-peak linewidth (ΔH PP ), gyromagnetic factor (g), number of spins (N S ), and spin-spin relaxation time (T 2 ) were strongly dependent on both temperature and super-exchange interaction. This information is important for possible nanotechnological applications, mainly those which are strongly dependent on the magnetic parameters.

  14. The oculomotor system of decapod cephalopods: eye muscles, eye muscle nerves, and the oculomotor neurons in the central nervous system.

    Science.gov (United States)

    Budelmann, B U; Young, J Z

    1993-04-29

    Fourteen extraocular eye muscles are described in the decapods Loligo and Sepioteuthis, and thirteen in Sepia; they are supplied by four eye muscle nerves. The main action of most of the muscles is a linear movement of the eyeball, only three muscles produce strong rotations. The arrangement, innervation and action of the decapod eye muscles are compared with those of the seven eye muscles and seven eye muscle nerves in Octopus. The extra muscles in decapods are attached to the anterior and superior faces of the eyes. At least, the anterior muscles, and presumably also the superior muscles, are concerned with convergent eye movements for binocular vision during fixation and capture of prey by the tentacles. The remaining muscles are rather similar in the two cephalopod groups. In decapods, the anterior muscles include conjunctive muscles; these cross the midline and each presumably moves both eyes at the same time during fixation. In the squids Loligo and Sepioteuthis there is an additional superior conjunctive muscle of perhaps similar function. Some of the anterior muscles are associated with a narrow moveable plate, the trochlear cartilage; it is attached to the eyeball by trochlear membranes. Centripetal cobalt fillings showed that all four eye muscle nerves have fibres that originate from somata in the ipsilateral anterior lateral pedal lobe, which is the oculomotor centre. The somata of the individual nerves show different but overlapping distributions. Bundles of small presumably afferent fibres were seen in two of the four nerves. They do not enter the anterior lateral pedal lobe but run to the ventral magnocellular lobe; some afferent fibres enter the brachio-palliovisceral connective and run perhaps as far as the palliovisceral lobe.

  15. A comparison of fishery biology of jumbo flying squid,Dosidicus gigas outside three Exclusive Economic Zones in the Eastern Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    LIU Bilin; CHEN Xinjun; YI Qian

    2013-01-01

    Although many studies on the fishery biology of jumbo flying squid,Dosidicus gigas,have been conducted in the coastal areas within Exclusive Economic Zones (EEZs) of various countries due to its commercial and ecological importance,limited biological information is available from waters outside these EEZs.In this paper,we examined D.gigas fishery biology from waters outside Chilean,Peruvian and Costa Rican EEZs,based on the fishery data collected by Chinese jigging vessels during 2006 to 2010.The dominant mantle lengths of D.gigas were 350-450 mm,250-400 mm and 250-350 mm outside Chilean,Peruvian and Costa Rican EEZs,respectively.Size structure analysis show that a medium-sized group existed mostly in the waters outside the Chilean and Peruvian EEZs,whereas a small-sized group occurred mainly in the waters outside the Costa Rican EEZ.The longevity of the squid outside the Costa Rican EEZ was less than 10 months,while most of those outside Chilean and Peruvian EEZs were about 1-1.5 years and very few large individuals were 1.5-2 years old.A higher percentage of mature individuals existed outside Costa Rican EEZ implying the region as a potential spawning ground,while lower proportions of mature squid outside the Peruvian and Chilean EEZs indicated that spawning may be occurring outside our study area.Spatial differences in sizes at maturity of the squid are thought to be result from different environmental factors especially different temperature and nutrition among the three areas.Stomach-content analysis showed that cannibalism was important in the diet of D.gigas.Stress generated by jigging may increase the incidence of cannibalism.

  16. Lateral line analogue aids vision in successful predator evasion for the brief squid, Lolliguncula brevis.

    Science.gov (United States)

    York, Carly A; Bartol, Ian K

    2014-07-15

    Cephalopods have visual and mechanoreception systems that may be employed to sense and respond to an approaching predator. While vision presumably plays the dominant role, the importance of the lateral line analogue for predator evasion has not been examined in cephalopods. To test the respective roles of vision and the lateral line analogue, brief squid, Lolliguncula brevis, were observed in the presence of summer flounder, Paralichthys dentatus, under light and dark conditions with their lateral line analogue intact and ablated. Hair cell ablation was achieved through a pharmacological technique used for the first time on a cephalopod. The proportion of predator-prey interactions survived was significantly higher in the light non-ablated and light ablated groups compared with the dark ablated group. The mean number of interactions survived varied across treatment groups with the light non-ablated group having significantly more success than the light ablated, dark non-ablated and dark ablated groups. These findings demonstrate that although vision is the primary sense, the lateral line analogue also contributes to predator evasion in squid. © 2014. Published by The Company of Biologists Ltd.

  17. Detection of nuclear magnetic resonance in the microtesla range using a high Tc dc-SQUID

    International Nuclear Information System (INIS)

    Wang Ning; Jin Yirong; Li Shao; Ren Yufeng; Tian Ye; Chen Yingfei; Li Jie; Chen Genghua; Zheng Dongning

    2012-01-01

    We have detected the ultra-low field nuclear magnetic resonance signal from water samples using a high-T c dc-SQUID sensor. The measurements were carried out in a homemade magnetically shielded room. Resonance spectra of 1 H from tap water and other substance samples were obtained in the field range from 7-110μT corresponding to resonance frequency 300-4.68kHz. Two kind of experimental systems were built, the first one is a directly coupled system, its signal to noise ratio in a single-shot measurement is around 4 for about 15 ml water. The second one used a Cu coil to transfer the flux to the SQUID sensor. Signal to noise ratio was improved to about 20 in a single-shot measurement for 5ml water, which benefits from the improvement of coupling efficiency. The effect of residual gradient in the magnetically shielded room was also investigated. J-coupling of 2,2,2-Trifluoroethyl alcohol was measured, the peaks are consistent with high field results.

  18. Detection of nuclear magnetic resonance in the microtesla range using a high Tc dc-SQUID

    Science.gov (United States)

    Wang, Ning; Jin, Yirong; Li, Shao; Ren, Yufeng; Tian, Ye; Chen, Yingfei; Li, Jie; Chen, Genghua; Zheng, Dongning

    2012-12-01

    We have detected the ultra-low field nuclear magnetic resonance signal from water samples using a high-Tc dc-SQUID sensor. The measurements were carried out in a homemade magnetically shielded room. Resonance spectra of 1H from tap water and other substance samples were obtained in the field range from 7-110μT corresponding to resonance frequency 300-4.68kHz. Two kind of experimental systems were built, the first one is a directly coupled system, its signal to noise ratio in a single-shot measurement is around 4 for about 15 ml water. The second one used a Cu coil to transfer the flux to the SQUID sensor. Signal to noise ratio was improved to about 20 in a single-shot measurement for 5ml water, which benefits from the improvement of coupling efficiency. The effect of residual gradient in the magnetically shielded room was also investigated. J-coupling of 2,2,2-Trifluoroethyl alcohol was measured, the peaks are consistent with high field results.

  19. NOAA TIFF Image - 1 m Backscatter Mosaic of an inshore portion of the NPS's Virgin Islands Coral Reef National Monument, south of St. John, US Virgin Islands, Project NF-05-05, 2005, UTM 20 WGS84 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the inshore portion of the NPS's Virgin Islands Coral Reef National Monument, south of St. John, US...

  20. Quantum versus thermally excited fluxoid transitions in a SQUID ring

    International Nuclear Information System (INIS)

    Kurkijaervi, J.

    1980-01-01

    The possibility of quantum tunneling as a mechanism for fluxoid transitions in a SQUID ring is carefully considered neglecting, however, dissipation arising from the quasiparticle current. The tunneling rates are compared with the thermally excited transition rates. The type of experiment Jackel et al. carried out in order to observe the thermal process is analyzed for observing the quantum tunneling. We find the expected result that the temperature at which the quantum process should begin to dominate depends essentially on ω 0 = 1/√LC of the ring. If an underdamped junction with C -13 F can be made the quantum tunneling temperature range should be easy to attain. (orig.)

  1. Thermal activation and macroscopic quantum tunneling in a DC SQUID

    International Nuclear Information System (INIS)

    Sharifi, F.; Gavilano, J.L.; VanHarlingen, D.J.

    1989-01-01

    The authors report measurements of the transition rate from metastable minima in the two-dimensional 1 of a dc SQUID as a function of applied flux temperature. The authors observe a crossover from energy-activated escape to macroscopic quantum tunneling at a critical temperature. The macroscopic quantum tunneling rate is substantially reduced by damping, and also broadens the crossover region. Most interestingly, the authors observe thermal rates that are suppressed from those predicted by the two-dimensional thermal activation model. The authors discuss possible explanations for this based on the interaction of the macroscopic degree of freedom in the device and energy level effects

  2. Reproducible fabrication and characterization of YBa2Cu3O7 Josephson junctions and SQUIDs on SrTiO3 bi-crystal substrates

    International Nuclear Information System (INIS)

    Kromann, R.; Vase, P.; Shen, Y.Q.; Freltoft, T.

    1993-01-01

    The fabrication of Josephson junctions and SQUIDs using ceramic high T c superconductors continues to be a subject of great interest and activity. In the case of the YBCO family of superconductors, most of the research effort has been concentrated on the grain boundary junctions. This type of junction can be fabricated in a controlled way by a variety of approaches, such as the bi-crystal technique, the bi-epitaxial technique or the step-edge technique. From a fabrication point of view, the bi-crystal technique is by far the simplest of the three. The availability of (100) SrTiO 3 bi-crystals on a commercial basis has lead to the possibility of making Josephson junctions by a simple process involving only one deposition and one patterning step. Reproducibility of the junction parameters between junctions on the same chip is a key point for electronic applications of Josephson junctions requiring a large amount of Josephson junctions working at the same time, as for example in the voltage standard. Another key point is the uniformity of the barrier, i.e. the extent to which the junction behaves as an ideal SIS junction. In this work junction uniformity has been studied by Frauenhofer diffraction patterns. The Josephson junctions have also been used in the fabrication of dc SQUIDs. In this work we have tried to optimize the magnitude of the voltage modulation from the SQUID by varying the design parameters. The SQUIDs have been characterized in terms of I c , R n , voltage modulation and noise properties. (orig.)

  3. Magnetic properties of Fe/ZnSe and Fe/GaAs heterostructures investigated by ferromagnetic resonance and SQUID measurements

    Czech Academy of Sciences Publication Activity Database

    Meckenstock, R.; Spodding, D.; Himmelbauer, K.; Krenn, H.; Doi, M.; Keune, W.; Frait, Zdeněk; Pelzl, J.

    2002-01-01

    Roč. 240, - (2002), s. 410-413 ISSN 0304-8853 Institutional research plan: CEZ:AV0Z1010914 Keywords : ferromagnetic resonance * squid * anisotropy-growth-induced * relaxation-magnetic Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.046, year: 2002

  4. Development of N-layer materials for SNS junction and SQUID applications

    International Nuclear Information System (INIS)

    Zhou, J.P.; McDevitt, J.T.; Jia, Q.

    1997-01-01

    Materials characteristics including water reactivity, oxygen loss, electromigration of oxide ions, and interfacial reactivity problems have plagued attempts to produce reliable and reproducible cuprate SNS superconductor junctions. In an effort to solve some of these formidable problems, new N-layer compounds from the family of R 1-x Ca x Ba 2-y La y Cu 3-z M z O 7-δ (R = Y, Gd and Pr; M = Co, Ni and Zn; 0 2 Cu 3 O 7-δ phase and the modified materials exhibit enhanced durability properties. The compounds have been utilized to make both SNS junctions and SQUID devices

  5. Optical extinction of size-controlled aerosols generated from squid chromatophore pigments

    Directory of Open Access Journals (Sweden)

    Sean R. Dinneen

    2017-10-01

    Full Text Available Nanophotonic granules populate the interior of cephalopod chromatophores, contributing to their visible color by selectively absorbing and scattering light. Inspired by the performance of these granules, we fabricated nanostructured aerosols by nebulizing a pigment solution extracted from native squid chromatophores. We determined their optical extinction using cavity ring-down spectroscopy and show how extinction cross section is dependent on both particle concentration and size. This work not only advances the fundamental knowledge of the optical properties of chromatophore pigments but also serves as a proof-of-concept method that can be adapted to develop coatings derived from these pigmentary aerosols.

  6. Mapping of Ambient Magnetic Fields within Liquid Helium Dewar for Testing of a DC SQUID Magnetometer

    International Nuclear Information System (INIS)

    Newhouse, Randal

    2003-01-01

    In an effort to explore the cavity lights phenomenon, Experimental Facilities Department at SLAC is testing a DC SQUID magnetometer. Due to the nature of the SQUID magnetometer and the intended tests, the earth's magnetic field must be negated. It is proposed to reduce ambient fields using bucking coils. First, however, an accurate map of the magnetic field inside the liquid helium Dewar where the experiment is going to take place needed to be made. This map was made using a three-axis fluxgate magnetometer mounted on a 3D positioning device made for this purpose. A ten inch tall volume within the Dewar was measured at data points approximately an inch from each other in all three axes. A LabVEIW program took readings from the magnetometer at 2 ms intervals for 1000 readings in such a way as to eliminate any ambient 60 Hz signals that may be present in the data. This data was stored in spreadsheet format and was analyzed to determine how the magnetic field within the Dewar was changing as a function of position

  7. NCBI nr-aa BLAST: CBRC-TTRU-01-1187 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-1187 ref|YP_002970996.1| NADH dehydrogenase subunit 6 [Loligo opalesce...ns] gb|ACS12932.1| NADH dehydrogenase subunit 6 [Loligo opalescens] YP_002970996.1 0.12 23% ...

  8. Effect of Bovine Plasma Protein on Autolysis and Gelation of Protein Extracted from Giant Squid (Dosidicus gigas Mantle

    Directory of Open Access Journals (Sweden)

    Laura Raquel Marquez-Alvarez

    2015-01-01

    Full Text Available The effect of bovine plasma protein (BPP on the inhibition of autolytic activity and its effect on the gelling properties of a protein concentrate (PC obtained from jumbo squid (Dosidicus gigas mantle were investigated. Sols and gels were prepared from the PC by adding different amounts of BPP (0, 1, and 2%. Dynamic oscillatory measurements indicated that systems with 1% BPP had a higher elastic modulus (G′, in which hydrophobic interactions were favored. Concerning the technological and textural quality of the gels, BPP caused a greater water holding capacity (WHC, force, cohesiveness, and elasticity, probably due to improvement of the electrostatic and hydrophobic interactions during gel formation. Scanning electron microscopy (SEM allowed visualization of the formation of more rigid and ordered gels with less porosity when BPP was added. Therefore, the addition of BPP improved the gelling capacity of proteins extracted from giant squid.

  9. Sensory, chemical and bacteriological changes during storage of iced squid ( Todaropsis eblanae )

    DEFF Research Database (Denmark)

    Paarup, T.; Sanchez, J.A.; Moral, A.

    2002-01-01

    Aims: To relate sensory shelf-life of iced whole and gutted squid to bacterial growth and chemical changes. Methods and Results: Cooked mantles from whole and gutted individuals were rejected after 10 and 12 days of storage, respectively, due to ammoniacal off-odours. Rate of production of both...... to spoilage through activity in the digestive gland, followed by diffusion of volatile compounds and amines to the mantle. Significance and Impact of the Study: Due to the psychrophilic nature of P. phosphoreum and Pseudoalteromonas sp., spread- plating and low temperature incubation are recommended...

  10. Characterizing the host and symbiont proteomes in the association between the Bobtail squid, Euprymna scolopes, and the bacterium, Vibrio fischeri.

    Directory of Open Access Journals (Sweden)

    Tyler R Schleicher

    Full Text Available The beneficial symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium, Vibrio fischeri, provides a unique opportunity to study host/microbe interactions within a natural microenvironment. Colonization of the squid light organ by V. fischeri begins a lifelong association with a regulated daily rhythm. Each morning the host expels an exudate from the light organ consisting of 95% of the symbiont population in addition to host hemocytes and shed epithelial cells. We analyzed the host and symbiont proteomes of adult squid exudate and surrounding light organ epithelial tissue using 1D- and 2D-polyacrylamide gel electrophoresis and multidimensional protein identification technology (MudPIT in an effort to understand the contribution of both partners to the maintenance of this association. These proteomic analyses putatively identified 1581 unique proteins, 870 proteins originating from the symbiont and 711 from the host. Identified host proteins indicate a role of the innate immune system and reactive oxygen species (ROS in regulating the symbiosis. Symbiont proteins detected enhance our understanding of the role of quorum sensing, two-component signaling, motility, and detoxification of ROS and reactive nitrogen species (RNS inside the light organ. This study offers the first proteomic analysis of the symbiotic microenvironment of the adult light organ and provides the identification of proteins important to the regulation of this beneficial association.

  11. SQUID measurements of remanent magnetisation in refillable 3He spin-filter cells (SFC)

    Science.gov (United States)

    Hutanu, V.; Rupp, A.; Sander-Thömmes, T.

    2007-07-01

    A strong influence of external magnetic fields on the relaxation time constant T1 of glass cells serving as reservoirs for polarised 3He, observed for various alkali metal-coated cells made of different glass types, was initially associated with the presence of a large number of ferromagnetic clusters on the glass surface. Later experiments showed the presence of the so-called “ T1 hysteresis” phenomenon with a similar distinctiveness also in uncoated cells made of pure synthetic quartz glass. It suggests that the origin of such a relaxation is a macroscopic magnetisation in the bulk of the cell. We present the results of a multi-SQUID system investigation on magnetised and non-magnetised quartz glass cells, Cs coated as well as bare wall, to be used as neutron spin filters at HMI Berlin. The presence of a macroscopic remanent magnetic moment in the cells after their exposition to external magnetic fields has been experimentally shown. More than 80% of the remanent magnetic moment of the magnetised cells was found to be concentrated in the region of the glass valves. SQUID measurements reveal the existence of some remanent magnetisation in all valve parts and also in the vacuum grease, but most magnetic are the plastic parts and the O-ring. Different valve and sealing types have been compared in order to find the less magnetisable one.

  12. Reproductive behavior in the squid Sepioteuthis australis from South Australia: interactions on the spawning grounds.

    Science.gov (United States)

    Jantzen, Troy M; Havenhand, Jon N

    2003-06-01

    Squid behavior is synonymous with distinctive body patterns, postures, and movements that constitute a complex visual communication system. These communications are particularly obvious during reproduction. They are important for sexual selection and have been identified as a potential means of species differentiation. Here we present a detailed account of copulation, mating, and egg deposition behaviors from in situ observations of the squid Sepioteuthis australis from South Australia. We identified four mating types from 85 separate mating attempts: "Male-upturned mating" (64% of mating attempts); "Sneaker mating" (33%); "Male-parallel" (2%); and "Head-to-head" (1%). Intervals between successive egg deposition behaviors were clearly bimodal, with modes at 2.5 s and 70.0 s. Ninety-three percent of egg capsules contained 3 or 4 eggs (mean = 3.54), and each egg cluster contained between 218 and 1922 egg capsules (mean = 893.9). The reproductive behavior of S. australis from South Australia was different from that described for other cephalopod species. More importantly, comparison between these results and those for other populations of S. australis suggests that behavior may differ from one population to another.

  13. A Transient Exposure to Symbiosis-Competent Bacteria Induces Light Organ Morphogenesis in the Host Squid.

    Science.gov (United States)

    Doino, J A; McFall-Ngai, M J

    1995-12-01

    Recent studies of the symbiotic association between the Hawaiian sepiolid squid Euprymna scolopes and the luminous bacterium Vibrio fischeri have shown that colonization of juvenile squid with symbiosis-competent bacteria induces morphogenetic changes of the light organ. These changes occur over a 4-day period and include cell death and tissue regression of the external ciliated epithelium. In the absence of bacterial colonization, morphogenesis does not occur. To determine whether the bacteria must be present throughout the morphogenetic process, we used the antibiotic chloramphenicol to clear the light organ of bacteria at various times during the initial colonization. We provide evidence in this study that a transient, 12-hour exposure to symbiosis-competent bacteria is necessary and sufficient to induce tissue regression in the light organ over the next several days. Further, we show that successful entrance into the light organ is necessary to induce morphogenesis, suggesting that induction results from bacterial interaction with internal crypt cells and not with the external ciliated epithelium. Finally, no difference in development was observed when the light organ was colonized by a mutant strain of V. fischeri that did not produce autoinducer, a potential light organ morphogen.

  14. Transcriptome analysis of the white body of the squid Euprymna tasmanica with emphasis on immune and hematopoietic gene discovery.

    Directory of Open Access Journals (Sweden)

    Karla A Salazar

    Full Text Available In the mutualistic relationship between the squid Euprymna tasmanica and the bioluminescent bacterium Vibrio fischeri, several host factors, including immune-related proteins, are known to interact and respond specifically and exclusively to the presence of the symbiont. In squid and octopus, the white body is considered to be an immune organ mainly due to the fact that blood cells, or hemocytes, are known to be present in high numbers and in different developmental stages. Hence, the white body has been described as the site of hematopoiesis in cephalopods. However, to our knowledge, there are no studies showing any molecular evidence of such functions. In this study, we performed a transcriptomic analysis of white body tissue of the Southern dumpling squid, E. tasmanica. Our primary goal was to gain insights into the functions of this tissue and to test for the presence of gene transcripts associated with hematopoietic and immune processes. Several hematopoiesis genes including CPSF1, GATA 2, TFIID, and FGFR2 were found to be expressed in the white body. In addition, transcripts associated with immune-related signal transduction pathways, such as the toll-like receptor/NF-κβ, and MAPK pathways were also found, as well as other immune genes previously identified in E. tasmanica's sister species, E. scolopes. This study is the first to analyze an immune organ within cephalopods, and to provide gene expression data supporting the white body as a hematopoietic tissue.

  15. Population structure of Vibrio fischeri within the light organs of Euprymna scolopes squid from Two Oahu (Hawaii) populations.

    Science.gov (United States)

    Wollenberg, M S; Ruby, E G

    2009-01-01

    We resolved the intraspecific diversity of Vibrio fischeri, the bioluminescent symbiont of the Hawaiian sepiolid squid Euprymna scolopes, at two previously unexplored morphological and geographical scales. These scales ranged from submillimeter regions within the host light organ to the several kilometers encompassing two host populations around Oahu. To facilitate this effort, we employed both novel and standard genetic and phenotypic assays of light-organ symbiont populations. A V. fischeri-specific fingerprinting method and five phenotypic assays were used to gauge the genetic richness of V. fischeri populations; these methods confirmed that the symbiont population present in each adult host's light organ is polyclonal. Upon statistical analysis of these genetic and phenotypic population data, we concluded that the characteristics of symbiotic populations were more similar within individual host populations than between the two distinct Oahu populations of E. scolopes, providing evidence that local geographic symbiont population structure exists. Finally, to better understand the genesis of symbiont diversity within host light organs, the process of symbiosis initiation in newly hatched juvenile squid was examined both experimentally and by mathematical modeling. We concluded that, after the juvenile hatches, only one or two cells of V. fischeri enter each of six internal epithelium-lined crypts present in the developing light organ. We hypothesize that the expansion of different, crypt-segregated, clonal populations creates the polyclonal adult light-organ population structure observed in this study. The stability of the luminous-bacterium-sepiolid squid mutualism in the presence of a polyclonal symbiont population structure is discussed in the context of contemporary evolutionary theory.

  16. Compensation for longitudinal chromatic aberration in the eye of the firefly squid, Watasenia scintillans.

    Science.gov (United States)

    Kröger, Ronald H H; Gislén, Anna

    2004-01-01

    The camera eyes of fishes and cephalopods have come forth by convergent evolution. In a variety of vertebrates capable of color vision, longitudinal chromatic aberration (LCA) of the optical system is corrected for by the exactly tuned longitudinal spherical aberration (LSA) of the crystalline lens. The LSA leads to multiple focal lengths, such that several wavelengths can be focused on the retina. We investigated whether that is also the case in the firefly squid (Watasenia scintillans), a cephalopod species that is likely to have color vision. It was found that the lens of W. scintillans is virtually free of LSA and uncorrected for LCA. However, the eye does not suffer from LCA because of a banked retina. Photoreceptors sensitive to short and long wavelengths are located at appropriate distances from the lens, such that they receive well-focused images. Such a design is an excellent solution for the firefly squid because a large area of the retina is monochromatically organized and it allows for double use of the surface area in the dichromatically organized part of the retina. However, it is not a universal solution since compensation for LCA by a banked retina requires that eye size and/or spectral separation between photopigments is small.

  17. Single-layer 2nd-order high-Tc SQUID gradiometer for use in unshielded environments

    International Nuclear Information System (INIS)

    Lee, Soon-Gul; Park, Seung Moon; Kang, Chan Seok; Kim, In-Seon; Kim, Sang-Jae

    2006-01-01

    We have studied the fabrication of second-order SQUID gradiometers from single-layer high-T c film and the feasibility of using those gradiometers in magnetocardiography. The gradiometer contains three parallel-connected pickup loops that are directly coupled to a step-edge junction SQUID with the coupling polarity of the center loop opposite to those of the two side loops. For a well-balanced gradiometer with a balancing factor of 10 3 , we achieved an unshielded gradient noise of 0.84 pT/cm 2 /Hz 1/2 at 1 Hz, which corresponds to an equivalent field noise of 280 fT/Hz 1/2 . A gradiometer with a 5.8-mm baseline successfully recorded the magnetocardic signals of a human subject, demonstrating the feasibility of using the device in biomagnetism. We have also studied the use of submicron YBCO bridges as Josephson elements of long-baseline gradiometers. The bridges were fabricated from 3-μm-wide, 300-nm-thick YBCO lines with a thin layer of Au on top by using a focused-ion-beam (FIB) patterning method. The temperature-dependent critical currents, I c (T), and the normal state resistances, R N (T), showed SIS-type behaviors, which are believed to be due to naturally formed grain boundaries.

  18. Detection of spatial hot spots and variation for the neon flying squid Ommastrephes bartramii resources in the northwest Pacific Ocean

    Science.gov (United States)

    Feng, Yongjiu; Chen, Xinjun; Liu, Yan

    2017-07-01

    With the increasing effects of global climate change and fishing activities, the spatial distribution of the neon flying squid ( Ommastrephes bartramii) is changing in the traditional fishing ground of 150°-160°E and 38°-45°N in the northwest Pacific Ocean. This research aims to identify the spatial hot and cold spots (i.e. spatial clusters) of O. bartramii to reveal its spatial structure using commercial fishery data from 2007 to 2010 collected by Chinese mainland squid-jigging fleets. A relatively strongly-clustered distribution for O. bartramii was observed using an exploratory spatial data analysis (ESDA) method. The results show two hot spots and one cold spot in 2007 while only one hot and one cold spots were identified each year from 2008 to 2010. The hot and cold spots in 2007 occupied 8.2% and 5.6% of the study area, respectively; these percentages for hot and cold spot areas were 5.8% and 3.1% in 2008, 10.2% and 2.9% in 2009, and 16.4% and 11.9% in 2010, respectively. Nearly half (>45%) of the squid from 2007 to 2009 reported by Chinese fleets were caught in hot spot areas while this percentage reached its peak at 68.8% in 2010, indicating that the hot spot areas are central fishing grounds. A further change analysis shows the area centered at 156°E/43.5°N was persistent as a hot spot over the whole period from 2007 to 2010. Furthermore, the hot spots were mainly identified in areas with sea surface temperature (SST) in the range of 15-20°C around warm Kuroshio Currents as well as with the chlorophyll- a (chl- a) concentration above 0.3 mg/m3. The outcome of this research improves our understanding of spatiotemporal hotspots and its variation for O. bartramii and is useful for sustainable exploitation, assessment, and management of this squid.

  19. Interference characterisation of a commercial Joule-Thomson cooler to be used in a SQUID-based heart monitor

    NARCIS (Netherlands)

    Bangma, M.R.; Bangma, M.R.; Rijpma, A.P.; de Vries, E.; Reincke, H.A.; Holland, Herman J.; ter Brake, Hermanus J.M.; Rogalla, Horst

    2001-01-01

    At the University of Twente, a foetal heart monitor based on a high-TC SQUID magnetometer system is under development. The purpose of this system is to measure a foetal heart signal in a clinical environment. For cooling a first demonstrator version, a closed-cycle Joule–Thomson cooler from APD

  20. Phospholipid synthesis in the squid giant axon: incorporation of lipid precursors

    Energy Technology Data Exchange (ETDEWEB)

    Gould, R.M.; Pant, H.; Gainer, H.; Tytell, M.

    1983-05-01

    The squid giant axon and extruded axoplasm from the giant axon were used to study the capacity of axoplasm for phospholipid synthesis. Extruded axoplasm, suspended in chemically defined media, catalyzed the synthesis of phospholipids from all of the precursors tested. /sup 32/P-Labeled inorganic phosphate and gamma-labeled ATP were actively incorporated into phosphatidylinositol phosphate, while (2-/sup 3/H)myo-inositol and L-(/sup 3/H(G))serine were actively incorporated into phosphatidylinositol and phosphatidylserine, respectively. Though less well utilized. (2-/sup 3/H)glycerol was incorporated into phosphatidic acid, phosphatidylinositol, and triglyceride, and methyl-3H)choline and (1-/sup 3/H)ethanolamine were incorporated into phosphatidylcholine and phosphatidylethanolamine, respectively. Isolated squid giant axons were incubated in artificial seawater containing the above precursors. The axoplasm was extruded following the incubations. Although most of the product lipids were recovered in the sheath (composed of cortical axoplasm, axolemma, and surrounding satellite cells), significant amounts (4-20%) were present in the extruded axoplasm. With tritiated choline and myo-inositol, the major labeled phospholipids found in both the extruded axoplasm and the sheath were phosphatidylcholine and phosphatidylinositol, respectively. With both glycerol and phosphate, phosphatidylethanolamine was a major labeled lipid in both axoplasm and sheath. These findings demonstrate that all classes of phospholipids are formed by endogenous synthetic enzymes in axoplasm. In addition, we feel that the different patterns of incorporation by intact axons and extruded axoplasm indicate that surrounding sheath cells contribute lipids to axoplasm. A comprehensive picture of axonal lipid metabolism should include axoplasmic synthesis and glial-axon transfer as pathways complementing the axonal transport of perikaryally formed lipids.

  1. Volumetric flow imaging reveals the importance of vortex ring formation in squid swimming tail-first and arms-first.

    Science.gov (United States)

    Bartol, Ian K; Krueger, Paul S; Jastrebsky, Rachel A; Williams, Sheila; Thompson, Joseph T

    2016-02-01

    Squids use a pulsed jet and fin movements to swim both arms-first (forward) and tail-first (backward). Given the complexity of the squid multi-propulsor system, 3D velocimetry techniques are required for the comprehensive study of wake dynamics. Defocusing digital particle tracking velocimetry, a volumetric velocimetry technique, and high-speed videography were used to study arms-first and tail-first swimming of brief squid Lolliguncula brevis over a broad range of speeds [0-10 dorsal mantle lengths (DML) s(-1)] in a swim tunnel. Although there was considerable complexity in the wakes of these multi-propulsor swimmers, 3D vortex rings and their derivatives were prominent reoccurring features during both tail-first and arms-first swimming, with the greatest jet and fin flow complexity occurring at intermediate speeds (1.5-3.0 DML s(-1)). The jet generally produced the majority of thrust during rectilinear swimming, increasing in relative importance with speed, and the fins provided no thrust at speeds >4.5 DML s(-1). For both swimming orientations, the fins sometimes acted as stabilizers, producing negative thrust (drag), and consistently provided lift at low/intermediate speeds (swimming orientation, and η for swimming sequences with clear isolated jet vortex rings was significantly greater (η=78.6±7.6%, mean±s.d.) than that for swimming sequences with clear elongated regions of concentrated jet vorticity (η=67.9±19.2%). This study reveals the complexity of 3D vortex wake flows produced by nekton with hydrodynamically distinct propulsors. © 2016. Published by The Company of Biologists Ltd.

  2. Population Structure of Vibrio fischeri within the Light Organs of Euprymna scolopes Squid from Two Oahu (Hawaii) Populations▿ †

    Science.gov (United States)

    Wollenberg, M. S.; Ruby, E. G.

    2009-01-01

    We resolved the intraspecific diversity of Vibrio fischeri, the bioluminescent symbiont of the Hawaiian sepiolid squid Euprymna scolopes, at two previously unexplored morphological and geographical scales. These scales ranged from submillimeter regions within the host light organ to the several kilometers encompassing two host populations around Oahu. To facilitate this effort, we employed both novel and standard genetic and phenotypic assays of light-organ symbiont populations. A V. fischeri-specific fingerprinting method and five phenotypic assays were used to gauge the genetic richness of V. fischeri populations; these methods confirmed that the symbiont population present in each adult host's light organ is polyclonal. Upon statistical analysis of these genetic and phenotypic population data, we concluded that the characteristics of symbiotic populations were more similar within individual host populations than between the two distinct Oahu populations of E. scolopes, providing evidence that local geographic symbiont population structure exists. Finally, to better understand the genesis of symbiont diversity within host light organs, the process of symbiosis initiation in newly hatched juvenile squid was examined both experimentally and by mathematical modeling. We concluded that, after the juvenile hatches, only one or two cells of V. fischeri enter each of six internal epithelium-lined crypts present in the developing light organ. We hypothesize that the expansion of different, crypt-segregated, clonal populations creates the polyclonal adult light-organ population structure observed in this study. The stability of the luminous-bacterium-sepiolid squid mutualism in the presence of a polyclonal symbiont population structure is discussed in the context of contemporary evolutionary theory. PMID:18997024

  3. A high-resolution mK-calorimeter applying SQUID-thermometry

    Energy Technology Data Exchange (ETDEWEB)

    Reifenberger, Andreas; Leps, Norman; Fleischmann, Andreas; Pies, Christian; Enss, Christian; Klingeler, Ruediger [Kirchhoff-Institut fuer Physik, Universitaet Heidelberg, INF 227,69120 Heidelberg (Germany)

    2012-07-01

    A new calorimeter for measuring single-crystalline samples of mg-size at ultra-low temperatures is described. Thermometry is done by means of a paramagnetic sensor material (Er-doped Au) in a low magnetic field. A temperature change results in a magnetization change which can be read out as change in magnetic flux by a superconducting quantum interference device (SQUID). This enables measurements in a wide temperature range (theoretically from 1 mK-1 K) with very high sensitivities. The bolometric design exhibits low addenda heat capacity and allows measurements of heat capacities from nJ/K to {mu}J/K by means of a temperature-relaxation method. The performance of the device is compared to a commercially available Quantum Design calorimeter in elsewise unchanged experimental settings in the temperature range from 15 mK to 500 mK.

  4. Description of plastic remains found in the stomach contents of the jumbo squid Dosidicus gigas landed in Ecuador during 2014.

    Science.gov (United States)

    Rosas-Luis, Rigoberto

    2016-12-15

    Squids are active and opportunistic predators that feed on a wide range of prey. Their active movements in the water column and their voracity promote a high consumption of food. In the pelagic environment off Ecuador, marine pollution is characterized by plastic debris with a mainland origin, including plastics trash of fishing gears. The objective of this work was to describe the presence of plastic remains in the stomach contents of Dosidicus gigas caught off the coast of Ecuador. Results demonstrated that 12% of the stomachs contained plastic remains. These plastics were identified as multifilament of polyethylene lines and polyvinyl chloride remains. Findings of this work could be related to an increase in the discharge of solid materials in the water column, increasing the probability to be ingested by the jumbo squid. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. The complete mitochondrial genome of the cryptic "lineage B" big-fin reef squid, Sepioteuthis lessoniana (Cephalopoda: Loliginidae) in Indo-West Pacific.

    Science.gov (United States)

    Shen, Kang-Ning; Yen, Ta-Chi; Chen, Ching-Hung; Ye, Jeng-Jia; Hsiao, Chung-Der

    2016-05-01

    In this study, the complete mitogenome sequence of the cryptic "lineage B" big-fin reef squid, Sepioteuthis lessoniana (Cephalopoda: Loliginidae) has been sequenced by next-generation sequencing method. The assembled mitogenome consisting of 16,694 bp, includes 13 protein coding genes, 25 transfer RNAs, 2 ribosomal RNAs genes. The overall base composition of "lineage B" S. lessoniana is 36.7% for A, 18.9 % for C, 34.5 % for T and 9.8 % for G and show 90% identities to "lineage C" S. lessoniana. It is also exhibits high T + A content (71.2%), two non-coding regions with TA tandem repeats. The complete mitogenome of the cryptic "lineage B" S. lessoniana provides essential and important DNA molecular data for further phylogeography and evolutionary analysis for big-fin reef squid species complex.

  6. Interference characterisation of a commercial Joule-Thomson cooler to be used in a SQUID-based foetal heart monitor

    NARCIS (Netherlands)

    Bangma, M.R.; Rijpma, A.P.; Vries, de E.; Reincke, H.A.; Holland, H.J.; Brake, ter H.J.M.; Rogalla, H.

    2001-01-01

    At the University of Twente, a fetal heart monitor based on a high-TC SQUID magnetometer system is under development. The purpose of this system is to measure a fetal heart signal in a clin. environment. For cooling a first demonstrator version, a closed-cycle Joule-Thomson cooler from APD

  7. Spatial variability of initial 230Th/ 232Th in modern Porites from the inshore region of the Great Barrier Reef

    Science.gov (United States)

    Clark, Tara R.; Zhao, Jian-xin; Feng, Yue-xing; Done, Terry J.; Jupiter, Stacy; Lough, Janice; Pandolfi, John M.

    2012-02-01

    The main limiting factor in obtaining precise and accurate uranium-series (U-series) ages of corals that lived during the last few hundred years is the ability to constrain and correct for initial thorium-230 ( 230Th 0), which is proportionally much higher in younger samples. This is becoming particularly important in palaeoecological research where accurate chronologies, based on the 230Th chronometer, are required to pinpoint changes in coral community structure and the timing of mortality events in recent time (e.g. since European settlement of northern Australia in the 1850s). In this study, thermal ionisation mass spectrometry (TIMS) U-series dating of 43 samples of known ages collected from living Porites spp. from the far northern, central and southern inshore regions of the Great Barrier Reef (GBR) was performed to spatially constrain initial 230Th/ 232Th ( 230Th/ 232Th 0) variability. In these living Porites corals, the majority of 230Th/ 232Th 0 values fell within error of the conservative bulk Earth 230Th/ 232Th atomic value of 4.3 ± 4.3 × 10 -6 (2 σ) generally assumed for 230Th 0 corrections where the primary source is terrestrially derived. However, the results of this study demonstrate that the accuracy of 230Th ages can be further improved by using locally determined 230Th/ 232Th 0 values for correction, supporting the conclusion made by Shen et al. (2008) for the Western Pacific. Despite samples being taken from regions adjacent to contrasting levels of land modification, no significant differences were found in 230Th/ 232Th 0 between regions exposed to varying levels of sediment during river runoff events. Overall, 39 of the total 43 230Th/ 232Th 0 atomic values measured in samples from inshore reefs across the entire region show a normal distribution ranging from 3.5 ± 1.1 to 8.1 ± 1.1 × 10 -6, with a weighted mean of 5.76 ± 0.34 × 10 -6 (2 σ, MSWD = 8.1). Considering the scatter of the data, the weighted mean value with a more

  8. Identifying the cellular mechanisms of symbiont-induced epithelial morphogenesis in the squid-Vibrio association.

    Science.gov (United States)

    Koropatnick, Tanya; Goodson, Michael S; Heath-Heckman, Elizabeth A C; McFall-Ngai, Margaret

    2014-02-01

    The symbiotic association between the Hawaiian bobtail squid Euprymna scolopes and the luminous marine bacterium Vibrio fischeri provides a unique opportunity to study epithelial morphogenesis. Shortly after hatching, the squid host harvests bacteria from the seawater using currents created by two elaborate fields of ciliated epithelia on the surface of the juvenile light organ. After light organ colonization, the symbiont population signals the gradual loss of the ciliated epithelia through apoptosis of the cells, which culminates in the complete regression of these tissues. Whereas aspects of this process have been studied at the morphological, biochemical, and molecular levels, no in-depth analysis of the cellular events has been reported. Here we describe the cellular structure of the epithelial field and present evidence that the symbiosis-induced regression occurs in two steps. Using confocal microscopic analyses, we observed an initial epithelial remodeling, which serves to disable the function of the harvesting apparatus, followed by a protracted regression involving actin rearrangements and epithelial cell extrusion. We identified a metal-dependent gelatinolytic activity in the symbiont-induced morphogenic epithelial fields, suggesting the involvement of Zn-dependent matrix metalloproteinase(s) (MMP) in light organ morphogenesis. These data show that the bacterial symbionts not only induce apoptosis of the field, but also change the form, function, and biochemistry of the cells as part of the morphogenic program.

  9. Ocean acidification responses in paralarval squid swimming behavior using a novel 3D tracking system

    KAUST Repository

    Zakroff, Casey J.

    2017-08-22

    Chronic embryonic exposure to ocean acidification (OA) has been shown to degrade the aragonitic statolith of paralarval squid, Doryteuthis pealeii, a key structure for their swimming behavior. This study examined if day-of-hatching paralarval D. pealeii from eggs reared under chronic OA demonstrated measurable impairments to swimming activity and control. This required the development of a novel, cost-effective, and robust method for 3D motion tracking and analysis. Squid eggs were reared in pCO2 levels in a dose-dependent manner ranging from 400 to 2200 ppm. Initial 2D experiments showed paralarvae in higher acidification environments spent more time at depth. In 3D experiments, velocity, particularly positive and negative vertical velocities, significantly decreased from 400 to 1000 ppm pCO2, but showed non-significant decreases at higher concentrations. Activity and horizontal velocity decreased linearly with increasing pCO2, indicating a subtle impact to paralarval energetics. Patterns may have been obscured by notable individual variability in the paralarvae. Responses were also seen to vary between trials on cohort or potentially annual scales. Overall, paralarval swimming appeared resilient to OA, with effects being slight. The newly developed 3D tracking system provides a powerful and accessible method for future studies to explore similar questions in the larvae of aquatic taxa.

  10. Effects of cholinergic compounds on the axon-Schwann cell relationship in the squid nerve fiber.

    Science.gov (United States)

    Villegas, J

    1975-04-01

    The effects of acetylcholine, carbamylcholine, D-tubocurarine, eserine, and alpha-bungarotoxin on the Schwann cell electrical potential of resting and stimulated squid nerve fibers were studied. Acetylcholine (10-7 M) and barbamylcholine (10-6 M) induce a prolonged hyper polarization in the Schwann cells of the unstimulated nerve fiber. In the presence of carbamylcholine (10-6 M) the behavior of the Schwann cell membrane to changes in the external potassium concentration approximates the behavior of an ideal potassium electrode. D-Tubocurarine (10-9 M) blocks the hyperpolarizing effects of nerve impulse trains and carbamylcholine (10-6 M), whereas at the same concentration eserine prolongs the Schwann cell hyperpolarizations induced by axon stimulation or by acetylcholine (10-7 M). alpha-Bungarotoxin (10-9M) also blocks the hyperpolarizing effect of nerve impulse trains and of carbamylcholine. D-Tubocurarine (10-5M) protects the Schwann cells against the irreversible action of alpha-bungarotoxin. These results show the existence of acetylcholine receptors in the Schwann cell membrane. Preliminary measurements of the binding of 125I-alpha bungarotoxin to the plasma membranes isolated from squid nerves also indicate the presence of acetylcholine receptors. These findings support the involvement of cholinergic mechanisms in the axon-Schwann cell relationship previously described.

  11. Reappraisal of the Trophic Ecology of One of the World's Most Threatened Spheniscids, the African Penguin.

    Directory of Open Access Journals (Sweden)

    Maëlle Connan

    Full Text Available Many species of seabirds, including the only penguin species breeding on the African continent, are threatened with extinction. The world population of the endangered African penguin Spheniscus demersus has decreased from more than 1.5 million individuals in the early 1900s to c.a. 23 000 pairs in 2013. Determining the trophic interactions of species, especially those of conservation concern, is important when declining numbers are thought to be driven by food limitation. By and large, African penguin dietary studies have relied on the identification of prey remains from stomach contents. Despite all the advantages of this method, it has well known biases. We therefore assessed the African penguin's diet, using stable isotopes, at two colonies in Algoa Bay (south-east coast of South Africa. These represent over 50% of the world population. Various samples (blood, feathers, egg membranes were collected for carbon and nitrogen stable isotope analyses. Results indicate that the trophic ecology of African penguins is influenced by colony, season and age class, but not adult sex. Isotopic niches identified by standard Bayesian ellipse areas and convex hulls, highlighted differences among groups and variability among individual penguins. Using Bayesian mixing models it was for the first time shown that adults target chokka squid Loligo reynaudii for self-provisioning during particular stages of their annual cycle, while concurrently feeding their chicks primarily with small pelagic fish. This has important ramifications and means that not only pelagic fish, but also squid stocks, need to be carefully managed in order to allow population recovery of African penguin.

  12. Managing small-scale commercial fisheries for adaptive capacity: insights from dynamic social-ecological drivers of change in Monterey Bay.

    Science.gov (United States)

    Aguilera, Stacy E; Cole, Jennifer; Finkbeiner, Elena M; Le Cornu, Elodie; Ban, Natalie C; Carr, Mark H; Cinner, Joshua E; Crowder, Larry B; Gelcich, Stefan; Hicks, Christina C; Kittinger, John N; Martone, Rebecca; Malone, Daniel; Pomeroy, Carrie; Starr, Richard M; Seram, Sanah; Zuercher, Rachel; Broad, Kenneth

    2015-01-01

    Globally, small-scale fisheries are influenced by dynamic climate, governance, and market drivers, which present social and ecological challenges and opportunities. It is difficult to manage fisheries adaptively for fluctuating drivers, except to allow participants to shift effort among multiple fisheries. Adapting to changing conditions allows small-scale fishery participants to survive economic and environmental disturbances and benefit from optimal conditions. This study explores the relative influence of large-scale drivers on shifts in effort and outcomes among three closely linked fisheries in Monterey Bay since the Magnuson-Stevens Fisheries Conservation and Management Act of 1976. In this region, Pacific sardine (Sardinops sagax), northern anchovy (Engraulis mordax), and market squid (Loligo opalescens) fisheries comprise a tightly linked system where shifting focus among fisheries is a key element to adaptive capacity and reduced social and ecological vulnerability. Using a cluster analysis of landings, we identify four modes from 1974 to 2012 that are dominated (i.e., a given species accounting for the plurality of landings) by squid, sardine, anchovy, or lack any dominance, and seven points of transition among these periods. This approach enables us to determine which drivers are associated with each mode and each transition. Overall, we show that market and climate drivers are predominantly attributed to dominance transitions. Model selection of external drivers indicates that governance phases, reflected as perceived abundance, dictate long-term outcomes. Our findings suggest that globally, small-scale fishery managers should consider enabling shifts in effort among fisheries and retaining existing flexibility, as adaptive capacity is a critical determinant for social and ecological resilience.

  13. Reappraisal of the Trophic Ecology of One of the World's Most Threatened Spheniscids, the African Penguin.

    Science.gov (United States)

    Connan, Maëlle; Hofmeyr, G J Greg; Pistorius, Pierre A

    2016-01-01

    Many species of seabirds, including the only penguin species breeding on the African continent, are threatened with extinction. The world population of the endangered African penguin Spheniscus demersus has decreased from more than 1.5 million individuals in the early 1900s to c.a. 23 000 pairs in 2013. Determining the trophic interactions of species, especially those of conservation concern, is important when declining numbers are thought to be driven by food limitation. By and large, African penguin dietary studies have relied on the identification of prey remains from stomach contents. Despite all the advantages of this method, it has well known biases. We therefore assessed the African penguin's diet, using stable isotopes, at two colonies in Algoa Bay (south-east coast of South Africa). These represent over 50% of the world population. Various samples (blood, feathers, egg membranes) were collected for carbon and nitrogen stable isotope analyses. Results indicate that the trophic ecology of African penguins is influenced by colony, season and age class, but not adult sex. Isotopic niches identified by standard Bayesian ellipse areas and convex hulls, highlighted differences among groups and variability among individual penguins. Using Bayesian mixing models it was for the first time shown that adults target chokka squid Loligo reynaudii for self-provisioning during particular stages of their annual cycle, while concurrently feeding their chicks primarily with small pelagic fish. This has important ramifications and means that not only pelagic fish, but also squid stocks, need to be carefully managed in order to allow population recovery of African penguin.

  14. Reappraisal of the Trophic Ecology of One of the World’s Most Threatened Spheniscids, the African Penguin

    Science.gov (United States)

    Connan, Maëlle; Hofmeyr, G. J. Greg; Pistorius, Pierre A

    2016-01-01

    Many species of seabirds, including the only penguin species breeding on the African continent, are threatened with extinction. The world population of the endangered African penguin Spheniscus demersus has decreased from more than 1.5 million individuals in the early 1900s to c.a. 23 000 pairs in 2013. Determining the trophic interactions of species, especially those of conservation concern, is important when declining numbers are thought to be driven by food limitation. By and large, African penguin dietary studies have relied on the identification of prey remains from stomach contents. Despite all the advantages of this method, it has well known biases. We therefore assessed the African penguin’s diet, using stable isotopes, at two colonies in Algoa Bay (south-east coast of South Africa). These represent over 50% of the world population. Various samples (blood, feathers, egg membranes) were collected for carbon and nitrogen stable isotope analyses. Results indicate that the trophic ecology of African penguins is influenced by colony, season and age class, but not adult sex. Isotopic niches identified by standard Bayesian ellipse areas and convex hulls, highlighted differences among groups and variability among individual penguins. Using Bayesian mixing models it was for the first time shown that adults target chokka squid Loligo reynaudii for self-provisioning during particular stages of their annual cycle, while concurrently feeding their chicks primarily with small pelagic fish. This has important ramifications and means that not only pelagic fish, but also squid stocks, need to be carefully managed in order to allow population recovery of African penguin. PMID:27434061

  15. Optical parameters of the tunable Bragg reflectors in squid.

    Science.gov (United States)

    Ghoshal, Amitabh; Demartini, Daniel G; Eck, Elizabeth; Morse, Daniel E

    2013-08-06

    Cephalopods (e.g. octopus, squid and cuttlefish) dynamically tune the colour and brightness of their skin for camouflage and communication using specialized skin cells called iridocytes. We use high-resolution microspectrophotometry to investigate individual tunable Bragg structures (consisting of alternating reflectin protein-containing, high-refractive index lamellae and low-refractive index inter-lamellar spaces) in live and chemically fixed iridocytes of the California market squid, Doryteuthis opalescens. This subcellular, single-stack microspectrophotometry allows for spectral normalization, permitting use of a transfer-matrix model of Bragg reflectance to calculate all the parameters of the Bragg stack-the refractive indices, dimensions and numbers of the lamellae and inter-lamellar spaces. Results of the fitting analyses show that eight or nine pairs of low- and high-index layers typically contribute to the observed reflectivity in live cells, whereas six or seven pairs of low- and high-index layers typically contribute to the reflectivity in chemically fixed cells. The reflectin-containing, high-index lamellae of live cells have a refractive index proportional to the peak reflectivity, with an average of 1.405 ± 0.012 and a maximum around 1.44, while the reflectin-containing lamellae in fixed tissue have a refractive index of 1.413 ± 0.015 suggesting a slight increase of refractive index in the process of fixation. As expected, incremental changes in refractive index contribute to the greatest incremental changes in reflectivity for those Bragg stacks with the most layers. The excursions in dimensions required to tune the measured reflected wavelength from 675 (red) to 425 nm (blue) are a decrease from ca 150 to 80 nm for the high-index lamellae and from ca 120 to 50 nm for the low-index inter-lamellar spaces. Fixation-induced dimensional changes also are quantified, leading us to suggest that further microspectrophotometric analyses of this iridocyte

  16. Pygmy squids and giant brains: mapping the complex cephalopod CNS by phalloidin staining of vibratome sections and whole-mount preparations

    DEFF Research Database (Denmark)

    Wollesen, T; Loesel, R; Wanninger, A

    2009-01-01

    experiments are less time-consuming and allow a high throughput of samples. Besides other advantages summarized here, phalloidin reliably labels the entire neuropil of the CNS of all squids, cuttlefish and octopuses investigated. This facilitates high-resolution in toto reconstructions of the CNS...

  17. Reconstructing 3D profiles of flux distribution in array of unshunted Josephson junctions from 2D scanning SQUID microscope images

    International Nuclear Information System (INIS)

    Nascimento, F.M.; Sergeenkov, S.; Araujo-Moreira, F.M.

    2012-01-01

    By using a specially designed algorithm (based on utilizing the so-called Hierarchical Data Format), we report on successful reconstruction of 3D profiles of local flux distribution within artificially prepared arrays of unshunted Nb-AlO x -Nb Josephson junctions from 2D surface images obtained via the scanning SQUID microscope. The analysis of the obtained results suggest that for large sweep areas, the local flux distribution significantly deviates from the conventional picture and exhibits a more complicated avalanche-type behavior with a prominent dendritic structure. -- Highlights: ► The penetration of external magnetic field into an array of Nb-AlO x -Nb Josephson junctions is studied. ► Using Scanning SQUID Microscope, 2D images of local flux distribution within array are obtained. ► Using specially designed pattern recognition algorithm, 3D flux profiles are reconstructed from 2D images.

  18. On the occurrence of egg masses of the diamond-shaped squid Thysanoteuthis rhombus Troschel, 1857 in the subtropical eastern Atlantic (Canary Islands. A potential commercial species?

    Directory of Open Access Journals (Sweden)

    Alejandro Escanez

    2012-09-01

    Full Text Available Data on opportunistic sightings of diamond-shaped squid Thysanoteuthis rhombus egg masses in the Canary Islands (Atlantic Ocean are presented. A total of 16 egg masses of this species were recorded and photographed from 2000 to 2010 around the western islands of the archipelago (El Hierro, Tenerife and La Gomera. These data reveal the existence of an important spawning area for diamond-shaped squid around the Canary Islands, in subtropical east Atlantic waters. We provide preliminary data for the potential development of an artisanal fishery focused on this species, and a discussion on its potential impacts on the marine ecosystem.

  19. Fluctuations in coral health of four common inshore reef corals in response to seasonal and anthropogenic changes in water quality.

    Science.gov (United States)

    Browne, Nicola K; Tay, Jason K L; Low, Jeffrey; Larson, Ole; Todd, Peter A

    2015-04-01

    Environmental drivers of coral condition (maximum quantum yield, symbiont density, chlorophyll a content and coral skeletal growth rates) were assessed in the equatorial inshore coastal waters of Singapore, where the amplitude of seasonal variation is low, but anthropogenic influence is relatively high. Water quality variables (sediments, nutrients, trace metals, temperature, light) explained between 52 and 83% of the variation in coral condition, with sediments and light availability as key drivers of foliose corals (Merulina ampliata, Pachyseris speciosa), and temperature exerting a greater influence on a branching coral (Pocillopora damicornis). Seasonal reductions in water quality led to high chlorophyll a concentrations and maximum quantum yields in corals, but low growth rates. These marginal coral communities are potentially vulnerable to climate change, hence, we propose water quality thresholds for coral growth with the aim of mitigating both local and global environmental impacts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. The complete mitochondrial genome of the cryptic "lineage A" big-fin reef squid, Sepioteuthis lessoniana (Cephalopoda: Loliginidae) in Indo-West Pacific.

    Science.gov (United States)

    Hsiao, Chung-Der; Shen, Kang-Ning; Ching, Tzu-Yun; Wang, Ya-Hsien; Ye, Jeng-Jia; Tsai, Shiou-Yi; Wu, Shan-Chun; Chen, Ching-Hung; Wang, Chia-Hui

    2016-07-01

    In this study, the complete mitogenome sequence of the cryptic "lineage A" big-fin reef squid, Sepioteuthis lessoniana (Cephalopoda: Loliginidae) has been sequenced by the next-generation sequencing method. The assembled mitogenome consists of 16,605 bp, which includes 13 protein-coding genes, 22 transfer RNAs, and 2 ribosomal RNAs genes. The overall base composition of "lineage A" S. lessoniana is 37.5% for A, 17.4% for C, 9.1% for G, and 35.9% for T and shows 87% identities to "lineage C" S. lessoniana. It is also noticed by its high T + A content (73.4%), two non-coding regions with TA tandem repeats. The complete mitogenome of the cryptic "lineage A" S. lessoniana provides essential and important DNA molecular data for further phylogeography and evolutionary analysis for big-fin reef squid species complex.

  1. Study on the Formulation of Squid (Loligosp) Nugget Added with Yellow Pumpkin (Curcubitamoschata) Flour

    OpenAIRE

    Nurharyati, Lisa; ', Suparmi; Sari, N Ira

    2017-01-01

    This study aimed to determine the squid nugget formulation with the addition of pumpkin flour. It was evaluated for the organoleptic value and the proximate composition. The method used was an experimental method and designed as non-factorial completely randomized design (CRD). The treatments were addition of pumpkin flour into the mix, consisting of four levels, namely: N0 (without the addition of pumpkin flour), N1 (pumpkin flour 50 g), N2 (pumpkin flour 75 g) and N3 (pumpkin flour 100 g).B...

  2. Reproductive system and the spermatophoric reaction of the mesopelagic squid Octopoteuthis sicula (Ruppell 1844) (Cephalopoda : Octopoteuthidae) from southern African waters

    NARCIS (Netherlands)

    Hoving, H. J. T.; Lipinski, M. R.; Videler, J. J.

    2008-01-01

    Reproductive features of the poorly known oceanic squid Octopoteuthis sicula are described and quantified to gain insight into the reproductive biology of the species. The data are based on 39 complete and partial specimens from southern African waters, collected between 1975 and 2005. The specimens

  3. Development of a highly sensitive current and position monitor with HTS squids and an HTS magnetic shield

    International Nuclear Information System (INIS)

    Watanabe, T.; Ikeda, T.; Kase, M.; Yano, Y.; Watanabe, S.; Sasaki, Y.; Kawaguchi, T.

    2005-01-01

    A highly sensitive current and position monitor with HTS (High-Temperature Superconducting) SQUIDs (Superconducting QUantum Interference Device) and an HTS magnetic shield for the measurement of the intensity of faint beams, such as a radioisotope beam, has been developed for the RIKEN RI beam factory project. The HTS magnetic shield and the HTS current sensor including the HTS SQUID are cooled by a low-vibration pulse-tube refrigerator. Both the HTS magnetic shield and the HTS current sensor were fabricated by dip-coating a thin Bi 2 -Sr 2 -Ca 2 -Cu 3 -O x (Bi-2223) layer on 99.9% MgO ceramic substrates. The HTS technology enables us to develop a system equipped with a downsized and highly sensitive current monitor. Recently, a prototype system was completed and installed in the beam transport line of the RIKEN Ring Cyclotron to measure the DC-current of high-energy heavy-ion beams. As a result, we succeeded in measuring the intensity of the 600 nA 40 Ar 17+ beam (95 MeV/u). We describe the present status of the monitor system and the results of the beam measurements. (author)

  4. Nondestructive evaluation of braided carbon fiber composites with artificial defect using HTS-SQUID gradiometer

    International Nuclear Information System (INIS)

    Shinyama, Y.; Yamaji, T.; Hatsukade, Y.; Takai, Y.; Aly-Hassan, M.S.; Nakai, A.; Hamada, H.; Tanaka, S.

    2011-01-01

    We applied a current-injection-based NDE method using a HTS-SQUID gradiometer to a braided CFRP with artificial cracks. Current distributions in the braided CFRP were estimated from measured field gradient distributions. A small crack, in which a few carbon-fiber bundles were cut, was well detected from the current distributions. A cross-section of the CFRP showed that a density of the bundles at edges is higher than the other part. The experimental results demonstrated the capability of the method to detect sub-mm cracks. Braided carbon fiber reinforced plastics (CFRPs) are one of multifunctional materials with superior properties such as mechanical strength to normal CFRPs since the braided CFRPs have continuous fiber bundles. In this paper, we applied the current-injection-based nondestructive evaluation (NDE) method using a HTS-SQUID gradiometer to the braided CFRP for the detection of the breakage of the bundles. We prepared planar braided CFRP samples with and without artificial cracks of 1 and 2 mm lengths, and measured the current density distribution above the samples using the NDE method. In the measurement results, not only a few completely-cut bundles but also the additional partially-cut bundles were detected from decrease in the measured current density along the cut bundle around the cracks. From these results, we showed that it is possible to inspect a few partially-cut bundles in the braided CFRPs by the NDE method.

  5. Predation on larval Atlantic herring (Clupea harengus) in inshore waters of the Baltic Sea

    Science.gov (United States)

    Kotterba, Paul; Moll, Dorothee; von Nordheim, Lena; Peck, Myron A.; Oesterwind, Daniel; Polte, Patrick

    2017-11-01

    In fishery science, early life-stage survival and development are regarded as major factors driving the population dynamics of marine fishes. During the last century, the main research focus has been on the spatio-temporal match of larval fish and appropriate food (bottom-up processes). However, these field studies are often criticised for their limited capability to disentangle their results from mortality caused by predation since these top-down mechanisms are rarely studied. We examined the predation on herring (Clupea harengus) larvae in a Baltic inshore lagoon by investigating the spatio-temporal overlap of larval herring and their potential predators such as the dominant threespine stickleback (Gasterosteus aculeatus) in distinct habitats (sublittoral and littoral areas) using a set of different gears and sampling techniques. Despite significant spatial and temporal predator-prey overlap, stomach analyses suggested that very few larvae were consumed by sticklebacks, even if projected to the entire study area and season. Other well-known predators of clupeid larvae such as gelatinous plankton occur later in the year after young herring have migrated out of the system. The observed predation on herring larvae was much less than expected and appears being a minor factor in determining herring reproduction success in our study area, particularly if compared to other causes of mortality such as egg predation. Providing a relatively good shelter from predation might be a key element making transitional waters valuable nursery grounds for the offspring of migrating marine fish species.

  6. Development of Contaminant Detection System using HTS SQUIDs

    International Nuclear Information System (INIS)

    Ohtani, T.; Tanaka, S.; Narita, Y.; Ariyoshi, S.; Suzuki, S.

    2015-01-01

    In terms of food safety, mixture of contaminants in food is a serious problem for not only consumers but also manufacturers. In general, the target size of the metallic contaminant to be removed is 0.5 mm. However, it is a difficult task for manufacturers to achieve this target, because of lower system sensitivity. Therefore, we developed a food contaminant detection system based on high-Tc RF superconducting quantum interference devices (SQUIDs), which are highly sensitive magnetic sensors. This study aims to improve the signal to noise ratio (SNR) of the system and detect a 0.5 mm diameter steel ball. Using a real time digital signal processing technique along with analog band-pass filters, we improved the SNR of the system. Owing to the improved SNR, a steel ball with a diameter as small as 0.3 mm, with stand-off distance of 117 mm was successfully detected. These results suggest that the proposed system is a promising candidate for the detection of metallic contaminants in food products

  7. An interchangeable scanning Hall probe/scanning SQUID microscope

    International Nuclear Information System (INIS)

    Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin; Chen, Tse-Jun; Wang, M. J.; Ling, D. C.; Chi, C. C.; Chen, Jeng-Chung

    2014-01-01

    We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10 −7 T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La 2/3 Ca 1/3 MnO 3 thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K

  8. Dynamic Characteristics of S-band DC SQUID Amplifier

    DEFF Research Database (Denmark)

    Prokopenko, G. V.; Shitov, S. V.; Koshelets, I. L. L. V. P.

    2003-01-01

    A low-noise rf amplifier based on a de SQUID (SQA) has been tested in the frequency range 3.0-4.6 GHz in the open-loop configuration. The following parameters have been measured for the single-stage balanced type SQA at 4.0 GHz: gain (12 +/- 1) dB, 3 dB bandwidth of 500 MHz and noise temperature (1.......0 +/- 0.25) K. For the nonbalanced type SQA at 4.0 GHz gain was (15 +/-1) dB, 3 dB bandwidth 200 MHz and noise temperature (0.5 +/- 0.25) K. The improved performance is obtained due to the increased characteristic voltage (approximate to 420 muV) of the small-area (down to 0.7-0.9 mum(2)) high-quality Nb......-AlOx-Nb SIS junctions. The saturation power (normalized to 1 GHz) referred to the input at 1 dB gain compression is estimated as approximate to55 K*GHz at a bias voltage of 60 muV. The reasons for saturation of the SQA are discussed....

  9. Microbiological Quality of Some Major Fishery Products Exported from India

    Energy Technology Data Exchange (ETDEWEB)

    Kamat, A. S.; Bandekar, J. R.M.; Karani, S.; Jadhav, R.; Shashidhar, A.; Kakatkar, S.; Pingulkar, K.; Ghadge, N; Warrier, S. B.R.; Venugopal, V. [Bhabha Atomic Research Centre, Mumbai (India); Panda, K. [Central Institute of Fisheries Education, Mumbai (India); Bhat, A. [Vikram University, Ujjain (India)

    2005-01-15

    The export quality marine and aquaculture fish and fishery products were collected from European Union Approved (EUA) and EU-non-approved (EUN) plants located at east and west coast of India and were analysed for the presence of human bacterial pathogens using standard bacteriological techniques. A total of 126 samples comprising of 26 marine shrimp (Penaeus indicus), 18 freshwater prawn, scampi (Macrobrachium rosenbergii), 40 squid (Loligo sp.), six cuttle fish (Sepia sp.), 30 rohu (Lobia rohita) and six long fin herring (Citrocentrus sp.) were analysed. The samples were screened for aerobic plate count (APC) and pathogens including Salmonella spp., Vibrio cholerae, Vibrio parahaemolyticus, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, and Yersinia enterocolitica. It was observed that the marine products from EUN plants were of poorer microbiological quality as compared with products from EUA plants. Samples of squid (40%) and shrimp (28.5%) from EUN plants were found to be contaminated with Salmonella. However, V. cholerae, L. monocytogenes, and, Y. enterocolitica were not detected in any of the samples tested. Shrimp samples (28%) from EUN plants were positive for Vibrio parahaemolyticus. Shrimp (14.3%) and squid (40%) were also contaminated with coagulase positive S. aureus. Salmonella contamination was observed in 16.7% of the cuttle fish samples from EUN plants. Whole herring samples were of acceptable microbiological quality. Of the freshwater items analyzed, whole rohu samples had higher microbial load as compared to processed rohu samples. All the rohu samples were free from the pathogens, however, 25% of the rohu steak samples had E. coli exceeding the limit of 20 cfu/g. Both whole as well as headless scampi harboured higher microbial load; whole (50%) and headless (41%) scampi samples were contaminated with Salmonella spp. The results suggested a need for implementation of better hygienic practices for the improvement of microbial

  10. The effect of sampling methods on the apparent constituents of ink from the squid Sepioteuthis australis.

    Science.gov (United States)

    Madaras, F; Gerber, J P; Peddie, F; Kokkinn, M J

    2010-11-01

    Results of experiments conducted on ink recovered from the squid Sepioteuthis australis indicate that there is no epinephrine or protein naturally present in the ink as it would be ejected in vivo. Protein content was effectively zero when ink was syringed from the duct end of the ink sac of freshly killed animals. By contrast, there were proteins in samples collected from dead specimens where ink was collected by a stripping method. From these samples, a single large molecular weight protein was identified as having tyrosinase activity. Digestion of syringed ink did not yield signs of melanin-bound proteins. Analysis of supernatants after centrifugation of squid ink consistently revealed the presence of DOPA, dopamine, and taurine, whereas epinephrine and nor-epinephrine were recorded from what was believed to be contaminated ink. Histological investigations of the ink sac revealed a compartmentalised glandular structure distal to the duct end. Closer observation of the glandular tissue showed that compartments increased in size as they matured and moved further into the lumen. It was concluded that the presence of epinephrine and tyrosinase (or a related protein) in the ink of S. australis could be attributed to rupturing of basal glandular compartments or contamination from other sources during the extraction process.

  11. The abundance of herbivorous fish on an inshore Red Sea reef following a mass coral bleaching event

    KAUST Repository

    Khalil, Maha T.

    2013-01-08

    A healthy herbivore community is critical for the ability of a reef to resist and recover from severe disturbances and to regain lost coral cover (i.e., resilience). The densities of the two major herbivorous fish groups (the family Acanthuridae and scarine labrids) were comparatively studied for an inshore reef that was severely impacted by a mass coral bleaching event in 2010 and an unaffected reef within the same region. Densities were found to be significantly higher on the affected reef, most likely due to the high algal densities on that reef. However, densities of herbivores on both reefs were found to be on average about 1-2 orders of magnitude lower than previously published reports from some Pacific reefs and from Red Sea reefs in the Gulf of Aqaba and only slightly higher than Caribbean reefs. Thus, it is predicted that recovery for this reef and similarly affected reefs may be very slow. The protection of herbivores from overfishing and the introduction of other management strategies that maximize reef resilience in Saudi Arabian waters are highly recommended. © 2013 Springer Science+Business Media Dordrecht.

  12. Current distribution evaluation of dye-sensitized solar cell using HTS-SQUID-based magnetic measurement system

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Kenji, E-mail: Sakai-k@okayama-u.ac.jp; Tanaka, Kohei; Kiwa, Toshihiko; Tsukada, Keiji

    2016-11-15

    Highlights: • Current distribution and direction of dye-sensitized solar cell (DSSC) was measured. • Electrical current flowing in the indium tin oxide (ITO) glass substrate was uniform. • The distribution of electrical current depended on I–V characteristic. • Current direction changed when the performance of DSSC is low. - Abstract: The current flowing inside a dye-sensitized solar cell (DSSC) was measured using a high-temperature superconductor superconducting quantum interference device (HTS-SQUID)-based magnetic measurement system. Further, a new evaluation method of the DSSC, which is difficult to measure using the conventional method, was investigated to improve the characteristics of the DSSC. The tangential components of the magnetic field generated from the DSSC were measured using two HTS-SQUIDs, and the intensity and direction related to the electrical current were obtained by the measured magnetic field. The DSSCs prepared with different dyes and catalytic substances showed different current-intensity mapping. The current direction was different for the DSSC with low performance. In addition, the current flowing in the ITO layer of the ITO glass substrate was also measured and the results confirmed that it had uniform distribution. These results show that the current mapping and the direction of the electrical current depend on the internal factors of the DSSC, and the detection of the magnetic field distribution generated from it is expected to lead to its new evaluation method.

  13. Coral skeletal geochemistry as a monitor of inshore water quality

    International Nuclear Information System (INIS)

    Saha, Narottam; Webb, Gregory E.; Zhao, Jian-Xin

    2016-01-01

    Coral reefs maintain extraordinary biodiversity and provide protection from tsunamis and storm surge, but inshore coral reef health is degrading in many regions due to deteriorating water quality. Deconvolving natural and anthropogenic changes to water quality is hampered by the lack of long term, dated water quality data but such records are required for forward modelling of reef health to aid their management. Reef corals provide an excellent archive of high resolution geochemical (trace element) proxies that can span hundreds of years and potentially provide records used through the Holocene. Hence, geochemical proxies in corals hold great promise for understanding changes in ancient water quality that can inform broader oceanographic and climatic changes in a given region. This article reviews and highlights the use of coral-based trace metal archives, including metal transported from rivers to the ocean, incorporation of trace metals into coral skeletons and the current ‘state of the art’ in utilizing coral trace metal proxies as tools for monitoring various types of local and regional source-specific pollution (river discharge, land use changes, dredging and dumping, mining, oil spills, antifouling paints, atmospheric sources, sewage). The three most commonly used coral trace element proxies (i.e., Ba/Ca, Mn/Ca, and Y/Ca) are closely associated with river runoff in the Great Barrier Reef, but considerable uncertainty remains regarding their complex biogeochemical cycling and controlling mechanisms. However, coral-based water quality reconstructions have suffered from a lack of understanding of so-called vital effects and early marine diagenesis. The main challenge is to identify and eliminate the influence of extraneous local factors in order to allow accurate water quality reconstructions and to develop alternate proxies to monitor water pollution. Rare earth elements have great potential as they are self-referencing and reflect basic terrestrial input

  14. Coral skeletal geochemistry as a monitor of inshore water quality

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Narottam, E-mail: n.saha@uq.edu.au; Webb, Gregory E.; Zhao, Jian-Xin

    2016-10-01

    Coral reefs maintain extraordinary biodiversity and provide protection from tsunamis and storm surge, but inshore coral reef health is degrading in many regions due to deteriorating water quality. Deconvolving natural and anthropogenic changes to water quality is hampered by the lack of long term, dated water quality data but such records are required for forward modelling of reef health to aid their management. Reef corals provide an excellent archive of high resolution geochemical (trace element) proxies that can span hundreds of years and potentially provide records used through the Holocene. Hence, geochemical proxies in corals hold great promise for understanding changes in ancient water quality that can inform broader oceanographic and climatic changes in a given region. This article reviews and highlights the use of coral-based trace metal archives, including metal transported from rivers to the ocean, incorporation of trace metals into coral skeletons and the current ‘state of the art’ in utilizing coral trace metal proxies as tools for monitoring various types of local and regional source-specific pollution (river discharge, land use changes, dredging and dumping, mining, oil spills, antifouling paints, atmospheric sources, sewage). The three most commonly used coral trace element proxies (i.e., Ba/Ca, Mn/Ca, and Y/Ca) are closely associated with river runoff in the Great Barrier Reef, but considerable uncertainty remains regarding their complex biogeochemical cycling and controlling mechanisms. However, coral-based water quality reconstructions have suffered from a lack of understanding of so-called vital effects and early marine diagenesis. The main challenge is to identify and eliminate the influence of extraneous local factors in order to allow accurate water quality reconstructions and to develop alternate proxies to monitor water pollution. Rare earth elements have great potential as they are self-referencing and reflect basic terrestrial input

  15. Magnetic moment oscillation in ammonium perchlorate in a DC SQUID-based magnetic resonance experiment

    International Nuclear Information System (INIS)

    Montero, V.; Cernicchiaro, G.

    2008-01-01

    In this work we describe experimental results in which a DC SQUID (superconducting quantum interference device) is used as free induction decay detector. Measurements of a solid ammonium perchlorate (NH 4 ClO 4 ) sample were performed, in zero field, at 4.2 K. Unexpected magnetic moment oscillations were detected at 1.5 kHz. The computation of the magnetic fields suggests that the proton nuclear magnetic resonance may explain the measured resonance, considering reorientation of the ammonium group by quantum tunneling of protons and a magnetic proton dipole-dipole intermolecular interaction model

  16. High-Tc dc-SQUID gradiometers in flip-chip configuration

    International Nuclear Information System (INIS)

    Peiselt, K; Schmidl, F; Linzen, S; Anton, A S; Huebner, U; Seidel, P

    2003-01-01

    We describe a new design of a gradiometric flip-chip antenna, which is inductively coupled to a dc-SQUID gradiometer. Both components are patterned out of thin films of the high-T c superconductor YBa 2 Cu 3 O 7-x (YBCO). For the flip-chip antenna, a 40 mm x 10 mm SrTiO 3 single crystalline substrate is used, while the gradiometer sensors are prepared on 10 mm x 10 mm SrTiO 3 bicrystal substrates. Special attention is paid to the inductive coupling between the flip-chip antenna and the read-out gradiometer antenna. We investigate different designs of coupling loops in order to optimize the coupling inductance between both components of the sensor. With optimized coupling the sensor achieves a field-gradient resolution of 12 fT cm -1 Hz -1/2 in the white noise region and of 310 fT cm -1 Hz -1/2 at 1 Hz in the unshielded laboratory environment

  17. High-Tc dc-SQUID gradiometers in flip-chip configuration

    Science.gov (United States)

    Peiselt, K.; Schmidl, F.; Linzen, S.; Anton, A. S.; Hübner, U.; Seidel, P.

    2003-12-01

    We describe a new design of a gradiometric flip-chip antenna, which is inductively coupled to a dc-SQUID gradiometer. Both components are patterned out of thin films of the high-Tc superconductor YBa2Cu3O7-x (YBCO). For the flip-chip antenna, a 40 mm × 10 mm SrTiO3 single crystalline substrate is used, while the gradiometer sensors are prepared on 10 mm × 10 mm SrTiO3 bicrystal substrates. Special attention is paid to the inductive coupling between the flip-chip antenna and the read-out gradiometer antenna. We investigate different designs of coupling loops in order to optimize the coupling inductance between both components of the sensor. With optimized coupling the sensor achieves a field-gradient resolution of 12 fT cm-1 Hz-1/2 in the white noise region and of 310 fT cm-1 Hz-1/2 at 1 Hz in the unshielded laboratory environment.

  18. UHV-cluster-tool for fabrication of thin film structures and transport- and noise properties of YBa2Cu3O7-δ grain boundary-SQUIDs

    International Nuclear Information System (INIS)

    Back, Christoph

    2007-01-01

    A UHV-thin-film-deposition system for the fabrication of thin film structures of metals and oxides was designed and optimized. For oxide materials, Pulsed Laser Deposition (PLD) was implemented. Epitaxial thin film growth can be analyzed during the PLD process by high-pressure RHEED (Reflection High-Energy Electron Diffraction). Furthermore layer-by-layer growth can be triggered by Pulsed Laser Intervall Deposition (PLiD). Heteroepitaxial multilayers can be fabricated automatically. Metal thin films can be grown by planar magnetron sputtering and by electron beam evaporation. Furthermore the system contains an rf-plasma source for surface cleaning and Ion Beam Etching (IBE). The three different deposition techniques are located in separate vacuum chambers which are connected by a central handling chamber allowing to combine all these processes in-situ. Furthermore superconducting quantum interference devices (SQUIDs) were fabricated out of epitaxially grown high-temperature superconducting YBa 2 Cu 3 O 7 -films on bicrystals. The SQUIDs were structured using a combined process of ion milling and chemical wet etching. By this combined etching process, edge signals that appear during imaging of flux quanta by low temperature scanning microscopy can be avoided. The transport- and noise properties of the SQUIDs were investigated. (orig.)

  19. Evaluation of jumbo squid (Dosidicus gigas byproduct hydrolysates obtained by acid-enzymatic hydrolysis and by autohydrolysis in practical diets for Pacific white shrimp (Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Mayra Lizett González-Félix

    2014-09-01

    Full Text Available The marine bioprocessing industry offers great potential to utilize byproducts for fish meal replacement in aquafeeds. Jumbo squid is an important fishery commodity in Mexico, but only the mantle is marketed. Head, fins, guts and tentacles are discarded in spite of being protein-rich byproducts. This study evaluated the use of two jumbo squid byproduct hydrolysates obtained by acid-enzymatic hydrolysis (AEH and by autohydrolysis (AH as ingredients in practical diets for shrimp. The hydrolysates were included at levels of 2.5 and 5.0% of the diet dry weight in four practical diets, including a control diet without hydrolysate. Shrimp growth and survival were not significantly affected by the dietary treatments. Postharvest quality of abdominal muscle was evaluated in terms of proximate composition and sensory evaluation. Significantly higher crude protein was observed in the muscle of shrimp fed the highest hydrolysate levels, AH 5% (204.8 g kg- 1 or AEH 5% (201.3 g kg- 1. Sensory analysis of cooked muscle showed significant differences for all variables evaluated: color, odor, flavor, and firmness. It was concluded that Jumbo squid byproducts can be successfully processed by autohydrolysis or acid-enzymatic hydrolysis, and that up to 5.0% of the hydrolysates can be incorporated into shrimp diets without affecting growth or survival.

  20. Highly Sensitive Measurements of the Dark Current of Superconducting Cavities for TESLA Using a SQUID Based Cryogenic Current Comparator

    CERN Document Server

    Vodel, W; Nietzsche, S

    2004-01-01

    This contribution presents a Cryogenic Current Comparator (CCC) as an excellent tool for detecting dark currents generated, e.g. by superconducting cavities for the upcoming TESLA project (X-FEL) at DESY. To achieve the maximum possible energy the gradient of the superconducting RF cavities should be pushed close to the physical limit of 50 MV/m. The undesired field emission of electrons (so-called dark current) of the superconducting RF cavities at strong fields may limit the maximum gradient. The absolute measurement of the dark current in correlation with the gradient will give a proper value to compare and classify the cavities. The main component of the CCC is a highly sensitive LTS-DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the dark current. For this reason the input coil of the SQUID is connected across a special designed toroidal niobium pick-up coil for the passing electron beam. A noise limited current resolution of nearly 2 pA/√(Hz) with a measu...

  1. Ion implantation in superconducting niobium and Nb3 Sn thin films: adjustment of Josephson microbridges and SQUID devices

    International Nuclear Information System (INIS)

    Robic, J.Y.; Piaguet, J.; Duret, D.; Veler, J.C.; Veran, J.L.; Zenatti, D.

    1978-01-01

    The principles of operation of Josephson junctions and SQUIDS are resumed. An ion implantation technique for the adjustment of the critical current is presented. High quality superconducting thin films were obtained by electron gun evaporation of niobium on heated substrates. Polycrystalline Nb 3 Sn was made by annealing (1000 K, 10 -6 Torr) a multilayer structure of successively evaporated niobium and thin films. Selected ions (helium, neon, argon) were implanted at doses ranging from 10 13 to 10 17 cm -2 . After implantation the critical temperature, the critical current and the normal resistivity were measured on special photoetched geometries. The variations of these electrical properties depend on the nuclear energy loss. The critical temperature of Nb 3 Sn is decreased by ion implantation and can be increased again by a new annealing. The parameters of the ion implantation were defined in order to obtain a critical temperature slightly higher than the operating temperature. The geometries of the microbridges and the implanted areas where then chosen to obtain appropriate criticals currents (approximately 10 μA) at the operating temperature. The obtained microbridges were used as junction elements in superconducting quantum interference devices (SQUID)

  2. Squids, snakes, and polarimeters: A new technique for measuring the magnetic moments of polarized beams

    International Nuclear Information System (INIS)

    Cameron, P.R.; Luccio, A.U.; Shea, T.J.; Tsoupas, N.; Goldberg, D.A.

    1997-01-01

    Effective polarimetry at high energies in hadron and lepton synchrotrons has been a long-standing and difficult problem. In synchrotrons with polarized beams it is possible to cause the direction of the polarization vector of a given bunch to alternate at a frequency which is some subharmonic of the rotation frequency. This can result in the presence of lines in the beam spectrum which are due only to the magnetic moment of the beam and which are well removed from the various lines due to the charge of the beam. The magnitude of these lines can be calculated from first principles. They are many orders of magnitude weaker than the Schottky signals. Measurement of the magnitude of one of these lines would be an absolute measurement of beam polarization. For measuring magnetic field, the Superconducting Quantum Interference Device, or squid, is about five orders of magnitude more sensitive than any other transducer. Using a squid, such a measurement might be accomplished with the proper combination of shielding, pickup loop design, and filtering. The resulting instrument would be fast, non-destructive, and comparatively cheap. In addition, techniques developed in the creation of such an instrument could be used to measure the Schottky spectrum in unprecedented detail. We present specifics of a polarimeter design for the Relativistic Heavy Ion Collider (RHIC) and briefly discuss the possibility of using this technique to measure polarization at high-energy electron machines like LEP and HERA. copyright 1997 American Institute of Physics

  3. An interchangeable scanning Hall probe/scanning SQUID microscope

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Tse-Jun; Wang, M. J. [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Ling, D. C. [Department of Physics, Tamkang University, Tamsui Dist., New Taipei City 25137, Taiwan (China); Chi, C. C.; Chen, Jeng-Chung [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2014-08-15

    We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10{sup −7} T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La{sub 2/3}Ca{sub 1/3}MnO{sub 3} thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K.

  4. SQUID biosusceptometry in the measurement of hepatic iron

    International Nuclear Information System (INIS)

    Sheth, Sujit

    2003-01-01

    Individuals with primary or secondary abnormalities of iron metabolism, such as hereditary hemochromatosis and transfusional iron loading, may develop potentially lethal systemic iron overload. Over time, this excess iron is progressively deposited in the liver, heart, pancreas, and other organs, resulting in cirrhosis, heart disease, diabetes and other disorders. Unless treated, death usually results from cardiac failure. The amount of iron in the liver is the best indicator of the amount of iron in the whole body. At present, the only sure way to measure the amount of iron in the liver is to remove a sample of the liver by biopsy. Iron stored in the liver can be magnetized to a small degree when placed in a magnetic field. The amount of magnetization is measured by our instrument, called a superconducting quantum interference device (SQUID) susceptometer. In patients with iron overload, our previous studies have shown that magnetic measurements of liver iron in patients with iron overload are quantitatively equivalent to biochemical determinations on tissue obtained by biopsy. The safety, ease, rapidity, and comfort of magnetic measurements make frequent, serial studies technically feasible and practically acceptable to patients. (orig.)

  5. Characterization of the cell polarity gene crumbs during the early development and maintenance of the squid-vibrio light organ symbiosis.

    Science.gov (United States)

    Peyer, Suzanne M; Heath-Heckman, Elizabeth A C; McFall-Ngai, Margaret J

    2017-11-01

    The protein Crumbs is a determinant of apical-basal cell polarity and plays a role in apoptosis of epithelial cells and their protection against photodamage. Using the squid-vibrio system, a model for development of symbiotic partnerships, we examined the modulation of the crumbs gene in host epithelial tissues during initiation and maintenance of the association. The extracellular luminous symbiont Vibrio fischeri colonizes the apical surfaces of polarized epithelia in deep crypts of the Euprymna scolopes light organ. During initial colonization each generation, symbiont harvesting is potentiated by the biochemical and biophysical activity of superficial ciliated epithelia, which are several cell layers from the crypt epithelia where the symbionts reside. Within hours of crypt colonization, the symbionts induce the cell death mediated regression of the remote superficial ciliated fields. However, the crypt cells directly interacting with the symbiont are protected from death. In the squid host, we characterized the gene and encoded protein during light organ morphogenesis and in response to symbiosis. Features of the protein sequence and structure, phylogenetic relationships, and localization patterns in the eye supported assignment of the squid protein to the Crumbs family. In situ hybridization revealed that the crumbs transcript shows opposite expression at the onset of symbiosis in the two different regions of the light organ: elevated levels in the superficial epithelia were attenuated whereas low levels in the crypt epithelia were turned up. Although a rhythmic association in which the host controls the symbiont population over the day-night cycle begins in the juvenile upon colonization, cycling of crumbs was evident only in the adult organ with peak expression coincident with maximum symbiont population and luminescence. Our results provide evidence that crumbs responds to symbiont cues that induce developmental apoptosis and to symbiont population

  6. Enlightenment of old ideas from new investigations: more questions regarding the evolution of bacteriogenic light organs in squids

    OpenAIRE

    Nishiguchi, M. K.; Lopez, J. E.; Boletzky, S. v.

    2004-01-01

    Bioluminescence is widespread among many different types of marine organisms. Metazoans contain two types of luminescence production, bacteriogenic (symbiotic with bacteria) or autogenic, via the production of a luminous secretion or the intrinsic properties of luminous cells. Several species in two families of squids, the Loliginidae and the Sepiolidae (Mollusca: Cephalopoda) harbor bacteriogenic light organs that are found central in the mantle cavity. These light organs are exceptional in ...

  7. SQUID-Detected MRI in the Limit of Zero Static Field

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, Nathan Dean [Univ. of California, Berkeley, CA (United States)

    2009-12-14

    This thesis describes an implementation of the so-called"zero-field MRI" (ZFMRI) pulse sequence, which allows for imaging in an arbitrarily low B0 field. The ZFMRI sequence created an effective unidirectional gradient field by using a train of pi pulses to average out the concomitant gradient components during encoding. The signals were acquired using a low-transition temperature dc Superconducting QUantum Interference Device (low-Tc dc SQUID) coupled to a first-order axial gradiometer. The experiments were carried out in a liquid helium dewar which was magnetically shielded with a single-layer mu-metal can around the outside and a superconducting Pb can contained within the helium space. We increased the filling factor of the custom-made, double-walled Pyrex insert by placing the liquid alcohol sample, at a temperature of approximately -50 degrees C, at the center of one loop of the superconducting gradiometer, which was immersed in the helium bath.

  8. Development of improved superconductive axial gradiometers for biomagnetic SQUID applications

    Science.gov (United States)

    Budnyk, M. M.; Minov, Yu. D.; Lyakhno, V. Yu.; Desnenko, V. A.; Linnik, A. S.; Shopen, O. B.

    2018-03-01

    SQUID magnetometers for biomagnetic measurements are equipped with superconductive gradiometers which are required to provide a high signal-to-noise ratio at low frequencies, sufficient mechanical strength and sustained performance under repeated thermal cycles, as well as a low level of intrinsic magnetic noise. This paper describes the design of a gradiometer made with a carbon-fiber reinforced composite material for magnetic cardiography measurements. The thermal coefficient of linear expansion (TCLE) of the carbon fiber composite can be precisely adjusted to match that of the superconducting detector coil wire. This is achieved thanks to the difference in the TCLE of carbon fibers in the longitudinal and transverse directions and is realized by varying the laying directions of the fiber in the composite. The data of magnetic susceptibility measurements on carbon fiber composite are reported, showing the magnetic susceptibility about six times smaller than that of graphite. The presented gradiometer design provides a high degree of balancing and is patented along side other specific techniques.

  9. EFFECT OF DETERGENT ON ELECTRICAL PROPERTIES OF SQUID AXON MEMBRANE.

    Science.gov (United States)

    KISHIMOTO, U; ADELMAN, W J

    1964-05-01

    The effects of detergents on squid giant axon action and resting potentials as well as membrane conductances in the voltage clamp have been studied. Anionic detergents (sodium lauryl sulfate, 0.1 to 1.0 mM; dimethyl benzene sulfonate, 1 to 20 mM, pH 7.6) cause a temporary increase and a later decrease of action potential height and the value of the resting potential. Cationic detergent (cetyl trimethyl ammonium chloride, 6 x 10(-5)M or more, pH 7.6) generally brings about immediate and irreversible decreases in the action and resting potentials. Non-ionic detergent (tween 80, 0.1 M, pH 7.6) causes a slight reversible reduction of action potential height without affecting the value of the resting potential. Both anionic and cationic detergents generally decrease the sodium and potassium conductances irreversibly. The effect of non-ionic detergent is to decrease the sodium conductance reversibly, leaving the potassium conductance almost unchanged.

  10. K/Na-triggered bioluminescence in the oceanic squid Symplectoteuthis oualaniensis.

    Science.gov (United States)

    Tsuji, F I; Leisman, G B

    1981-11-01

    A distinctive type of luminescent system present in the large dorsal luminous organ of the oceanic squid Symplectoteuthis oualaniensis is described. The organ produces an intense blue flash of light followed by a rapid decay in light intensity. Luminescence originates from numerous oval granules present in the luminous organ. The essential light-emitting components are membrane bound. Intact granules or washed homogenates of the granules are triggered to emit light by monovalent cations such as, in decreasing order of effectiveness, potassium, rubidium, sodium, cesium, ammonium, and lithium. Calcium, magnesium, and strontium ions do not trigger light emission. Analysis of the kinetics of the decay of light intensity suggests that two light-emitting components are involved, one decaying faster than the other. The light-emitting reaction has an absolute requirement for molecular oxygen. The optimum KCl or NaCl concentration is approximately 0.6 M and the optimum pH is approximately 7.8. A free sulfhydryl group is essential for activity.

  11. Development of contaminant detection system based on ultra-low field SQUID-NMR/MRI

    International Nuclear Information System (INIS)

    Tsunaki, S; Yamamoto, M; Hatta, J; Hatsukade, Y; Tanaka, S

    2014-01-01

    We have developed an ultra-low field (ULF) NMR/MRI system using an HTS-rf-SQUID and evaluated performance of the system as a contaminant detection system for foods and drinks. In this work, we measured 1D MRIs from water samples with or without various contaminants, such as aluminum and glass balls using the system. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. We measured 2D MRIs from food samples with and without a hole. In the 2D MRIs, the hole position in the sample was well visualized. These results show that the feasibility of the system to detect and localize contaminants in foods and drinks.

  12. First observations of the bigfin squid Magnapinna sp. in the Colombian Southern Caribbean.

    Science.gov (United States)

    Guerrero-Kommritz, Jurgen; Cantera, Jaime; Puentes, Vladimir; Leon, Jorge

    2018-01-01

    Herein, first observations are reported of Magnapinna squids in the Colombian Southern Caribbean. Two specimens were observed by Remote Operated Vehicles (ROV) during exploratory drilling surveys for hydrocarbons at 1,883 and 2,294 m depth. These are the first observations of specimens of Magnapinna in the Southern Caribbean. Resumen La primera observación del calamar Magnapinna sp. en el caribe sur colombiano. Dos especímenes de calamares de aleta grande fueron observados con submarino de operación remota (ROV) durante un proyecto de perforación exploratoria de hidrocaburos a profundidades de 1,883 y de 2,294 m, respectivamente. Estas son las primeras observaciones de especímenes de Magnapinna en el Caribe Sur.

  13. Distribution of squid and fish in the pelagic zone of the Cosmonaut Sea and Prydz Bay region during the BROKE-West campaign

    NARCIS (Netherlands)

    Van de Putte, Anton P.; Jackson, George D.; Pakhomov, Evgeny; Flores, Hauke; Volckaert, Filip A. M.

    The composition and distribution of squid and fish collected by Rectangular Midwater Trawls in the upper 200 m were investigated during the BROKE-West (Baseline Research on Oceanography, Krill and the Environment-West) survey (January-March 2006) in CCAMLR Subdivision 58.4.2 of the Southern Ocean. A

  14. Distribution of squid and fish in the pelagic zone of the Cosmonaut Sea and Prydz Bay region during the BROKE-West campaign

    NARCIS (Netherlands)

    Putte, van de A.P.; Jackson, G.D.; Pakhomov, E.; Florentino De Souza Silva, A.P.; Volckaert, F.A.M.

    2010-01-01

    The composition and distribution of squid and fish collected by Rectangular Midwater Trawls in the upper 200 m were investigated during the BROKE-West (Baseline Research on Oceanography, Krill and the Environment-West) survey (January-March 2006) in CCAMLR Subdivision 58.4.2 of the Southern Ocean. A

  15. The different types of sperm morphology and behavior within a single species

    Science.gov (United States)

    Hirohashi, Noritaka; Iwata, Yoko

    2013-01-01

    Some coastal squids exhibit male dimorphism (large and small body size) that is linked to mating behaviors. Large “consort” males compete with other, rival males to copulate with a female, and thereby transfer their spermatophores to her internal site around the oviduct. Small “sneaker” males rush to a single female or copulating pair and transfer spermatophores to her external body surface around the seminal receptacle near the mouth. We previously found that in Loligo bleekeri, sneaker sperm are ~50% longer than consort sperm, and only the sneaker sperm, once ejaculated from the spermatophore (sperm mass), form a cluster because of chemoattraction toward their own respiratory CO2. Here, we report that sperm clusters are able to move en masse. Because a fraction of ejaculated sperm from a sneaker’s spermatophore are eventually located in the female’s seminal receptacle, we hypothesize that sperm clustering facilitates collective migration to the seminal receptacle or an egg micropyle. Sperm clustering is regarded as a cooperative behavior that may have evolved by sperm competition and/or physical and physiological constraints imposed by male mating tactics. PMID:24567779

  16. The diet of the South American sea lion (Otaria flavescens at Río Negro, Patagonia, Argentina, during the winter-spring period

    Directory of Open Access Journals (Sweden)

    Raimundo L. Bustos

    2012-12-01

    Full Text Available The South American sea lion, Otaria flavescens (Shaw, 1800 population is steadily expanding along the Patagonian coast of Argentina in the last decades. However, little is known about the feeding ecology of the species in the area. The aim of this study was to analyze the food habits of O. flavescens from 91 scats collected at Río Negro province, during the winter and spring of 2005. Fish occurred in 96% of scats containing prey remains, followed by cephalopods (26%. Raneya brasiliensis (Kaup, 1856 was the most frequent and abundant species occurring in 58.6% of samples and constituting almost 50% of fish predated. Second in importance were Porichthys porosissimus (Cuvier, 1829 and Cynoscion guatucupa (Cuvier, 1830 in terms of occurrence (%FO 20.7 and numbers (29.6% respectively. The squid Loligo gahi (d'Orbigny, 1835 was the most frequent cephalopod prey (42.1%, whereas Octopus tehuelchus (d'Orbigny, 1834 was the most abundant (77%. The higher amount and diversity of prey found in the spring in comparison with the winter season might be related to a higher feeding activity of seals or to a seasonal increase in food availability in the area.

  17. Conversion of Squid Pen to Homogentisic Acid via Paenibacillus sp. TKU036 and the Antioxidant and Anti-Inflammatory Activities of Homogentisic Acid

    Directory of Open Access Journals (Sweden)

    San-Lang Wang

    2016-10-01

    Full Text Available The culture supernatant of Paenibacillus sp. TKU036, a bacterium isolated from Taiwanese soils, showed high antioxidant activity (85% when cultured in a squid pen powder (SPP-containing medium at 37 °C for three days. Homogentisic acid (2,5-dihydroxyphenylacetic acid, HGA was isolated and found to be the major antioxidant in the culture supernatant of the SPP-containing medium fermented by Paenibacillus sp. TKU036. Tryptophan was also present in the culture supernatant. The results of high-performance liquid chromatography (HPLC fingerprinting showed that HGA and tryptophan were produced via fermentation but did not pre-exist in the unfermented SPP-containing medium. Neither HGA nor tryptophan was found in the culture supernatants obtained from the fermentation of nutrient broth or other chitinous material, i.e., medium containing shrimp head powder, by Paenibacillus sp. TKU036. The production of HGA via microorganisms has rarely been reported. In this study, we found that squid pen was a potential carbon and nitrogen source for Paenibacillus sp. Tryptophan (105 mg/L and HGA (60 mg/L were recovered from the culture supernatant. The isolated HGA was found to have higher antioxidant activity (IC50 = 6.9 μg/mL than α-tocopherol (IC50 = 17.6 μg/mL. The anti-inflammatory activity of the isolated HGA (IC50 = 10.14 μg/mL was lower than that of quercetin (IC50 = 1.14 μg/mL. As a result, squid pen, a fishery processing byproduct, is a valuable material for the production of tryptophan and the antioxidant and anti-inflammatory HGA via microbial conversion.

  18. SQUID: sensorized shirt with smartphone interface for exercise monitoring and home rehabilitation.

    Science.gov (United States)

    Farjadian, Amir B; Sivak, Mark L; Mavroidis, Constantinos

    2013-06-01

    Stroke is a leading cause of serious long-term disability in the United States. There is a need for new technological adjuncts to expedite patients' scheduled discharge from hospital and pursue rehabilitation procedure at home. SQUID is a low-cost, smart shirt that incorporates a six-channel electromyography (EMG) and heart rate data acquisition module to deliver objective audiovisual and haptic biofeedback to the patient. The sensorized shirt is interfaced with a smartphone application, for the subject's usage at home, as well as the online database, for the therapist's remote supervision from hospital. A single healthy subject was recruited to investigate the system functionality during improperly performed exercise. The system can potentially be used in automated, remote monitoring of variety of physical therapy exercises, rooted in strength or coordination training of specific muscle groups.

  19. Marine mammal fauna of potential OTEC sites in the Gulf of Mexico and Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Payne, S.F.

    1979-05-01

    Twenty-seven marine mammal species have been recorded for the Gulf of Mexico, including 7 Mysticetes or baleen whales, 17 Odontocetes or toothed whales, 1 Sirenian (manatee), and 1 or 2 Pinnipeds or seals. The most common species in the Gulf is the bottlenosed dolphin, an inshore species. Offshore, the spotted dolphin, is fairly common. Most other species are recorded from very few sightings or strandings. None of the endangered species is common in potential OTEC sites in the Gulf of Mexico. Twenty-two marine mammals may occur in Hawaii; 2 Mystecetes, 19 Odonotocetes, and the endemic monk seal. The monk seal, an endangered species, lives in the extreme northwestern island chain away from potential OTEC sites. Among the most common cetaceans in Hawaii is the endangered humpback whale. The spinner dolphin and the bottlenosed dolphin are also fairly common. The baleen whales feed on zooplankton during the summer in polar waters, and are migratory, while the toothed whales feed mainly on fish and squid, and are found in temperate or tropical regions year-round. The manatee is vegetarian and the pinnipeds are fish- or squid-eaters. Environmental effects of OTEC which may affect mammals are: toxic effects of biocide release or ammonia spill, biostimulating effects of seawater redistribution, oil spills, or effects of the physical presence of OTEC plants.

  20. Population Structure of Vibrio fischeri within the Light Organs of Euprymna scolopes Squid from Two Oahu (Hawaii) Populations▿ †

    OpenAIRE

    Wollenberg, M. S.; Ruby, E. G.

    2008-01-01

    We resolved the intraspecific diversity of Vibrio fischeri, the bioluminescent symbiont of the Hawaiian sepiolid squid Euprymna scolopes, at two previously unexplored morphological and geographical scales. These scales ranged from submillimeter regions within the host light organ to the several kilometers encompassing two host populations around Oahu. To facilitate this effort, we employed both novel and standard genetic and phenotypic assays of light-organ symbiont populations. A V. fischeri...