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Sample records for neon flying squid

  1. [Trace elements in the statoliths of neon flying squid, Ommastrephes bartramii in the Northwest Pacific Ocean].

    PubMed

    Lu, Hua-Jie; Chen, Xin-Jun; Ma, Jin

    2014-08-01

    Statolith is one of the most important hard tissues of cephalopods which is widely used in the research of fisheries ecology including population structure, life history reconstruction and so on. Trace elements of 18 statoliths of neon flying squid Ommastrephes bartramii collected in the Northwest Pacific Ocean in 2007 by Chinese jigging fishing fleets were analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The results indicated that the statoliths of O. bartramii mainly contained 55 elements, and calcium (Ca), strontium (Sr), sodium (Na), phosphorus (P), potassium (K), silicon (Si), magnesium (Mg), boron (B), iron (Fe), barium (Ba) were the 10 most abundant elements. The analysis of variance showed that there was no significant difference in each element distribution between different sexual squid except for P, Si and B. Significant differences existed in the contents of Sr and Na but no significant difference was found in the contents of Ca, P, K, Si, Mg, B, Fe and Ba between different hatching populations. There were significant differences in the contents of Ca, Sr, Na, P, Mg and Ba, but no significant difference was found in the contents of K, Fe, B and Si in the statoliths among different growth zones. This study presented Sr and Na could be the best two trace elements used in the research on the population structure and life history reconstruction for O. bartramii. PMID:25509097

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

    PubMed

    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; 37-40N) and further expanded north towards the subarctic frontal zone (SAFZ; 40-44N) in July. The squid habitat hotspots within the KOTZ and areas west of the dateline (160W-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 (180-160W) 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. PMID:26571118

  3. The study on fishing ground of neon flying squid, Ommastrephes bartrami, and ocean environment based on remote sensing data in the Northwest Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Fan, Wei; Wu, Yumei; Cui, Xuesen

    2009-05-01

    The relationships between the neon flying squid, Ommastrephes bartrami, and the relative ocean environmental factors are analyzed. The environmental factors collected are sea surface temperature (SST), chlorophyll concentration (Chl- a) and sea surface height (SSH) from NASA, as well as the yields of neon flying squid in the North Pacific Ocean. The results show that the favorable temperature for neon flying squid living is 10°C-22°C and the favorite temperature is between 15°C-17°C. The Chl- a concentration is 0.1-0.6 mg/m3. When Chl- a concentration changes to 0.12-0.14 mg/m3, the probability of forming fishing ground becomes very high. In most fishing grounds, the SSH is higher than the mean SSH. The generalized additive model (GAM) was applied to analyze the correlations between neon flying squid and ocean environmental factors. Every year, squids migrate northward from June to August and return southward during October-November, and the characteristics of the both migrations are very different. When squids migrate to the north, most relationships between the yields and SST are positive. The relationships are negative when squids move to southward. The relationships between the yields and Chl- a concentrations are negative from June to October, and insignificant in November. There is no obvious correlation between the catches of squid and longitude, but good with latitude.

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

    PubMed Central

    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. PMID:26571118

  5. Characteristic of lipids and fatty acid compositions of the neon flying squid, Ommastrephes bartramii.

    PubMed

    Saito, Hiroaki; Ishikawa, Satoru

    2012-01-01

    The lipids and fatty acids of the neon flying squid (Ommastrephes bartramii) were an-alyzed to clarify its lipid physiology and health benefit as marine food. Triacylglycerols were the only major component in the digestive gland (liver). In all other organs (mantle, arm, integument, and ovary), sterols and phospholipids were the major components with noticeable levels of ceramide aminoethyl phosphonate and sphingomyelin. The significant levels of sphingolipids suggest the O. bartramii lipids is a useful source for cosmetics. Although the lipid content between the liver and all other tissues markedly differed from each other, the same nine dominant fatty acids in the triacylglycerols were found in all organs; 14:0, 16:0, 18:0, 18:1n-9, 20:1n-9, 20:1n-11, 22:1n-11, 20:5n-3 (icosapentaenoic acid, EPA), and 22:6n-3 (docosahexaenoic acid, DHA). Unusually high 20:1n-11 levels in the O. bartramii triacylglycerols were probably characteristic for western Pacific animal depot lipids, compared with non-detectable levels of 20:1n-11 reported in other marine animals. O. bartramii concurrently has high levels of DHA in their triacylglycerols. The major fatty acids in the phospholipids were 16:0, 18:0, 20:1n-9, EPA, and DHA without 20:1n-11. Markedly high levels of both EPA and DHA were observed in phosphatidylethanolamine, while only DHA was found as the major one in phosphatidylcholine. In particular, high levels of DHA were found both in its depot triacylglycerols and tissue phospholipids in all organs of O. bartramii, similar to that in highly migratory fishes. The high DHA levels in all its organs suggest that O. bartramii lipids is a healthy marine source for DHA supplements. PMID:23018852

  6. A review of interaction between neon flying squid ( Ommastrephes bartramii) and oceanographic variability in the North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Yu, Wei; Chen, Xinjun; Yi, Qian; Tian, Siquan

    2015-08-01

    The neon flying squid ( Ommastrephes bartramii) is a short-lived opportunistic species widely distributed in subtropical and temperate waters in the North Pacific Ocean. The life cycle of O. bartramii from planktonic eggs to nektonic adults is closely linked to oceanographic conditions. The fluctuations in O. bartramii abundance and distribution tend to increase and widen continuously due to the heavy influences of ocean-climate events on various spatio-temporal scales. In this study, we reviewed the interaction between O. bartramii and oceanography variability in the North Pacific with respect to large-scale climatic-oceanic phenomena including El Niño, La Niña, Kuroshio, Oyashio and Pacific Decadal Oscillation (PDO), as well as regional environmental variables such as sea surface temperature (SST), sea surface height (SSH), sea surface salinity (SSS), chlorophyll-a (Chl- a) concentration, and plankton density. The population dynamics of O. bartramii is mediated mainly by meso- and large-scale climatic-oceanic events ( e.g., Kuroshio and Oyashio Currents) rather than other local environmental conditions ( e.g., SST and Chl- a concentration), because all of the oceanographic influences are imposed on the context of large-scale climate changes ( e.g., PDO). An unstructured-grid finite-volume coastal ocean model coupled with an individual-based model is proposed to simulate relevant physical-biological oceanographic processes for identifying ocean-climate influence and predicting O. bartramii distribution and abundance in the North Pacific. Future research needs to be focused on improving the knowledge about early life history of O. bartramii and evaluating the relationship between marine physical environment and two separate passive drifting life stages of O. bartramii including free-floating eggs and planktonic paralarvae.

  7. Variability of Suitable Habitat of Western Winter-Spring Cohort for Neon Flying Squid in the Northwest Pacific under Anomalous Environments

    PubMed Central

    Yu, Wei; Chen, Xinjun; Yi, Qian; Chen, Yong; Zhang, Yang

    2015-01-01

    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 valuable insights into exploring the relationship between the underlying squid habitat and the inter-annual environmental change. PMID:25923519

  8. Variability of Suitable Habitat of Western Winter-Spring Cohort for Neon Flying Squid in the Northwest Pacific under Anomalous Environments.

    PubMed

    Yu, Wei; Chen, Xinjun; Yi, Qian; Chen, Yong; Zhang, Yang

    2015-01-01

    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 valuable insights into exploring the relationship between the underlying squid habitat and the inter-annual environmental change. PMID:25923519

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Influence of oceanological conditions on the distribution and biological features of the mass squid species in the South Kuril region

    NASA Astrophysics Data System (ADS)

    Novikov, Yu. V.; Slobodskoy, E. V.; Shevtsov, G. A.

    2007-04-01

    The distribution of the three mass commercial cephalopod species (the Japanese common squid Todarodes pacificus, the neon flying squid Ommastrephes bartramii, and the boreal clubhook squid Onychoteuthis borealijaponica) on the Pacific side of the South Kuril Islands is analyzed in relation to oceanological conditions using the data of scientific catches of squids and oceanographic observations obtained by Japanese and Russians research vessels in August September of 1994 1999. With respect to the extension of the waters of subtropical origin, three types of oceanological conditions are distinguished: the conventionally cold (1996, 1997), conventionally warm (1998, 1999) and conventionally normal (1994, 1995) conditions. It is shown that conventionally cold years are more favorable for the fishery of the Japanese common squid and the boreal clubhook squid and conventionally normal years are favorable for the fishery of all three squid species, while conventionally cold years are only favorable for the fishery of the neon flying squid. Particular features of the distribution and biology of each of the squid species considered are discussed.

  11. A comparison of fishery biology of jumbo flying squid, Dosidicus gigas outside three Exclusive Economic Zones in the Eastern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Liu, Bilin; Chen, Xinjun; Yi, Qian

    2013-05-01

    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.

  12. A Comparative Study of Clam and Squid. Biting Flies of the Coastal Region. Diatoms: Nature's Aquatic Gems. Learning Experiences for Coastal and Oceanic Awareness Studies, Nos. 227, 231, 232. [Project COAST].

    ERIC Educational Resources Information Center

    Delaware Univ., Newark. Coll. of Education.

    Included are three units related to coastal and oceanic awareness. The units are: (1) A Comparative Study of Clam and Squid; (2) Biting Flies of the Coastal Region; and (3) Diatoms: Nature's Aquatic Gems. All three units were designed for secondary school students. Each unit contains teacher background materials, student activity materials,

  13. A Comparative Study of Clam and Squid. Biting Flies of the Coastal Region. Diatoms: Nature's Aquatic Gems. Learning Experiences for Coastal and Oceanic Awareness Studies, Nos. 227, 231, 232. [Project COAST].

    ERIC Educational Resources Information Center

    Delaware Univ., Newark. Coll. of Education.

    Included are three units related to coastal and oceanic awareness. The units are: (1) A Comparative Study of Clam and Squid; (2) Biting Flies of the Coastal Region; and (3) Diatoms: Nature's Aquatic Gems. All three units were designed for secondary school students. Each unit contains teacher background materials, student activity materials,…

  14. First SQUIDs

    NASA Astrophysics Data System (ADS)

    Silver, Arnold

    2014-03-01

    The Superconducting QUantum Interference Device (SQUID) is the most sensitive magnetic flux sensor and the most widely applied superconductor electronic device, whose applications range from magnetocardiography to picovoltmeters, from digital logic to quantum computing, and from non-destructive testing to Gravity Probe B, a spaceborne test of Einstein's theory of gravity. In this presentation, I describe the initial experiments and device modeling at the Ford Scientific Laboratory that produced the early versions of the SQUID during the 1960's. That history originated in an anomalous observation during microwave ENDOR experiments and led to the first report of macroscopic quantum interference in superconductors in 1964 [Phys. Rev. Letters 12 (1964)]. The SQUID is based on London's electrodynamic theory of multiply-connected superconductors [Superfluids Wiley, New York (1950)], the magnetic flux quantum (h/2e=2.07E-15 Wb), and Josephson's theory of weakly-connected superconductors [Phys. Lett. 1 (1962)]. Physically, it incorporates Josephson tunnel junctions in a low inductance, superconducting ring. Two distinct types of SQUIDs were demonstrated: first the ``dc SQUID'' and then the ``rf SQUID.'' The former has two Josephson junctions and produces a dc frequency response; the latter has only one junction and responds only at rf and microwave frequencies. The first phase, conducted by Lambe, Jaklevic, Mercereau, and Silver, used type I thin film superconductors and Josephson tunnel junctions. The second phase, conducted by Silver and Zimmerman, used bulk niobium structures with ``cat whisker'' junction technology [Phys.Rev. 157 (1967)].

  15. Squid rocket science: How squid launch into air

    NASA Astrophysics Data System (ADS)

    O'Dor, Ron; Stewart, Julia; Gilly, William; Payne, John; Borges, Teresa Cerveira; Thys, Tierney

    2013-10-01

    Squid not only swim, they can also fly like rockets, accelerating through the air by forcefully expelling water out of their mantles. Using available lab and field data from four squid species, Sthenoteuthis pteropus, Dosidicus gigas, Illex illecebrosus and Loligo opalescens, including sixteen remarkable photographs of flying S. pteropus off the coast of Brazil, we compared the cost of transport in both water and air and discussed methods of maximizing power output through funnel and mantle constriction. Additionally we found that fin flaps develop at approximately the same size range as flight behaviors in these squids, consistent with previous hypotheses that flaps could function as ailerons whilst aloft. S. pteropus acceleration in air (265 body lengths [BL]/s2; 24.5m/s2) was found to exceed that in water (79BL/s2) three-fold based on estimated mantle length from still photos. Velocities in air (37BL/s; 3.4m/s) exceed those in water (11BL/s) almost four-fold. Given the obvious advantages of this extreme mode of transport, squid flight may in fact be more common than previously thought and potentially employed to reduce migration cost in addition to predation avoidance. Clearly squid flight, the role of fin flaps and funnel, and the energetic benefits are worthy of extended investigation.

  16. FLIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flies constitute a major group of nuisance species world wide in rural and urban situations. The public and health care officials can become more aware of the potential risks from flies and other urban pests by compiling the available information into an easily readable book form. Scientists from ...

  17. Portable neon purification system

    SciTech Connect

    Richardson, R.A.; Schmitt, R.L.

    1995-08-01

    This paper describes the principle design features of a portable neon purification system and the results of the system performance testing. Neon gas replaces air in the Ring Imaging Cherenkov detector without using vacuum, in experiment E781(SELEX) at Fermilab. The portable neon purification system purifies neon gas by, first purging air with CO{sub 2}, freezing the CO{sub 2}, then cryoadsorbing the remaining contaminants. The freezer removes carbon dioxide from a neon gas mixture down to a maximum concentration of 500 parts-per-million (ppm). The charcoal bed adsorber removes nitrogen from neon gas down to a maximum concentration of 100 ppm. The original RICH vessel was designed to hold vacuum but its photomultiplier tube plates were not.

  18. The Squid Challenge.

    ERIC Educational Resources Information Center

    Guillaume, Andrea M.

    1997-01-01

    Describes an approach to the study of squid that helps students of all ages develop richer ideas about the structure of living things, how living things are adapted to their habitats, and how they interact with other organisms. Highlights include the external and internal features of the squid, squid statements and statistics, and writing…

  19. Chimeras in SQUID metamaterials

    NASA Astrophysics Data System (ADS)

    Lazarides, N.; Neofotistos, G.; Tsironis, G. P.

    2015-02-01

    Regular lattices comprising superconducting quantum interference devices (SQUIDs) form magnetic metamaterials exhibiting extraordinary properties, including tunability, dynamic multistability, and negative magnetic permeability. The SQUIDs in a metamaterial interact through nonlocal, magnetic dipole-dipole forces that makes it possible for counterintuitive dynamic states referred to as chimera states to appear; the latter feature clusters of SQUIDs with synchronous dynamics which coexist with clusters exhibiting asynchronous behavior. The spontaneous appearance of chimera states is demonstrated numerically for one-dimensional SQUID metamaterials driven by an alternating magnetic field in which the fluxes threading the SQUID rings are randomly initialized; then, chimera states appear generically for sufficiently strong initial excitations, which exhibit relatively long lifetimes. The synchronization and metastability levels of the chimera states are discussed in terms of appropriate measures. Given that both one- and two-dimensional SQUID metamaterials have been already fabricated and investigated in the laboratory, the presence of a chimera state could in principle be detected with presently available experimental setups.

  20. High pressure neon arc lamp

    DOEpatents

    Sze, Robert C.; Bigio, Irving J.

    2003-07-15

    A high pressure neon arc lamp and method of using the same for photodynamic therapies is provided. The high pressure neon arc lamp includes a housing that encloses a quantity of neon gas pressurized to about 500 Torr to about 22,000 Torr. At each end of the housing the lamp is connected by electrodes and wires to a pulse generator. The pulse generator generates an initial pulse voltage to breakdown the impedance of the neon gas. Then the pulse generator delivers a current through the neon gas to create an electrical arc that emits light having wavelengths from about 620 nanometers to about 645 nanometers. A method for activating a photosensitizer is provided. Initially, a photosensitizer is administered to a patient and allowed time to be absorbed into target cells. Then the high pressure neon arc lamp is used to illuminate the target cells with red light having wavelengths from about 620 nanometers to about 645 nanometers. The red light activates the photosensitizers to start a chain reaction that may involve oxygen free radicals to destroy the target cells. In this manner, a high pressure neon arc lamp that is inexpensive and efficiently generates red light useful in photodynamic therapy is provided.

  1. Subranging scheme for SQUID sensors

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor)

    2008-01-01

    A readout scheme for measuring the output from a SQUID-based sensor-array using an improved subranging architecture that includes multiple resolution channels (such as a coarse resolution channel and a fine resolution channel). The scheme employs a flux sensing circuit with a sensing coil connected in series to multiple input coils, each input coil being coupled to a corresponding SQUID detection circuit having a high-resolution SQUID device with independent linearizing feedback. A two-resolution configuration (course and fine) is illustrated with a primary SQUID detection circuit for generating a fine readout, and a secondary SQUID detection circuit for generating a course readout, both having feedback current coupled to the respective SQUID devices via feedback/modulation coils. The primary and secondary SQUID detection circuits function and derive independent feedback. Thus, the SQUID devices may be monitored independently of each other (and read simultaneously) to dramatically increase slew rates and dynamic range.

  2. Low-noise SQUID

    DOEpatents

    Dantsker, Eugene (Torrance, CA); Clarke, John (Berkeley, CA)

    2000-01-01

    The present invention comprises a high-transition-temperature superconducting device having low-magnitude low-frequency noise-characteristics in magnetic fields comprising superconducting films wherein the films have a width that is less than or equal to a critical width, w.sub.C, which depends on an ambient magnetic field. For operation in the Earth's magnetic field, the critical width is about 6 micrometers (.mu.m). When made with film widths of about 4 .mu.m an inventive high transition-temperature, superconducting quantum interference device (SQUID) excluded magnetic flux vortices up to a threshold ambient magnetic field of about 100 microTesla (.mu.T). SQUIDs were fabricated having several different film strip patterns. When the film strip width was kept at about 4 .mu.m, the SQUIDs exhibited essentially no increase in low-frequency noise, even when cooled in static magnetic fields of magnitude up to 100 .mu.T. Furthermore, the mutual inductance between the inventive devices and a seven-turn spiral coil was at least 85% of that for inductive coupling to a conventional SQUID.

  3. SQUIDs: Then and Now

    NASA Astrophysics Data System (ADS)

    Clarke, John

    2014-03-01

    In 1964, Jaklevic, Lambe, Silver and Mercereau demonstrated quantum interference in a superconducting ring containing two Josephson tunnel junctions. This observation marked the birth of the SQUID--Superconducting QUantum Interference Device. The following year saw the appearance of the SLUG (Superconducting Low-inductance Undulatory Galvanometer)--a blob of solder frozen around a length of niobium wire--that was used as a voltmeter with femtovolt resolution. Although extremely primitive by today's standards, the SLUG was used successfully in a number of ultrasensitive experiments. Today, the square washer dc SQUID, fabricated on a wafer-scale from thin films with an integrated input coil, finds a wide range of applications. One example is the use of a SQUID amplifier to read out ADMX--Axion Dark Matter eXperiment--at the University of Washington, Seattle. This experiment, which involves a cooled microwave cavity surrounded by a superconducting magnet, searches for the axion, a candidate for cold dark matter. In the presence of a magnetic field the axion is predicted to decay into a photon, which is detected by the SQUID. In another example, the combination of a SQUID with prepolarized proton spins enables one to perform magnetic resonance imaging (MRI) in magnetic fields of the order of 0.1 mT, four orders of magnitude lower than in conventional MRI systems. In vivo images of the human brain acquired at these ultralow fields are able distinguish brain tissue, blood, cerebrospinal fluid and scalp fat using a combination of inversion recovery and multiple echo sequences. Potential clinical applications are briefly discussed.

  4. SQUID With Integral Flux Concentrator

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Sisk, Robert C.

    1989-01-01

    In improved superconducting quantum interference device (SQUID), change in size and shape of superconducting ring improves coupling to external signal coil and eases coil-positioning tolerances. More rugged and easier to manufacture than conventional SQUID's with comparable electrical characteristics. Thin-film superconducting flux concentrator utilizes Meissner effect to deflect magnetic field of signal coil into central hole of SQUID. Used in magnetometers, ammeters, analog-to-digital converters, and related electronic applications in which high signal-to-noise ratios required.

  5. Dissect Your Squid and Eat It Too!

    ERIC Educational Resources Information Center

    McGinnis, Patricia

    2001-01-01

    Introduces a science lab activity in which students dissect fresh squids in groups of four and observe the anatomy. Parent volunteers cook the squid mantle for kids to taste. Includes directions for squid dissection. (YDS)

  6. Biomagnetic susceptometer with SQUID instrumentation

    SciTech Connect

    Paulson, D.N.; Fagaly, R.L.; Toussaint, R.M. ); Fisher, R. )

    1991-03-01

    This paper discusses the use of a new SQUID magnetometer for noninvasive measurements of hepatic (liver) iron stores. Placement of the SQUID, detection coil, and magnetie in the dewar vacuum region significantly reduced system noise. In addition, the system incorporates multiple magnets and detection coils which may allow the discrimination of the surface skin layer from the deeper (weaker signal) true liver iron concentration. Measurements indicate an instrumental noise level {lt} 20 {mu}g/g of equivalent iron concentration.

  7. Demonstrating Fluorescence with Neon Paper and Plastic

    ERIC Educational Resources Information Center

    Birriel, Jennifer J.; Roe, Clarissa

    2015-01-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and…

  8. Demonstrating Fluorescence with Neon Paper and Plastic

    ERIC Educational Resources Information Center

    Birriel, Jennifer J.; Roe, Clarissa

    2015-01-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and

  9. Paleomagnetic Analysis Using SQUID Microscopy

    NASA Technical Reports Server (NTRS)

    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.

  10. High Performance 16 MHz SQUID Feedback Electronics.

    NASA Astrophysics Data System (ADS)

    Koch, R. H.; Rozen, J. R.; Wltgens, P.; Picunko, T.; Goss, W. J.; Lathrop, D. K.; Matthews, R.

    1996-03-01

    We have constructed a dc SQUID feedback circuit operating at a modulation frequency of 16 ; MHz. Using a wideband superconducting thin film transformer to impedance match the SQUID to a high frequency amplifier allows the system to operate at the SQUID noise level for most types of low-Tc SQUIDs. This system has a closed loop bandwidth exceeding 3 ; MHz and a slew rate of greater than 1 10 ^ 6 ? 0 /sec at frequencies upto 1 ; MHz . High-Tc SQUIDs have also been operated using a wirewound toroidal transformer with similar results. We will present a simple model of the maximum obtainable bandwidth and slew rate of a dc SQUID when operating in a feedback circuit. This system's bandwidth and slew rate as well as its very high dynamic range and low harmonic distortion allows SQUID magnetometers and gradiometers to be operated totally unshielded without unlocking in the dc, 60 Hz, and RFI electromagnetic fields typical of most SQUID applications.

  11. SQUID holder with high magnetic shielding

    NASA Technical Reports Server (NTRS)

    Rigby, K. W.; Marek, D.; Chui, T. C. P.

    1990-01-01

    A SQUID holder designed for high magnetic shielding is discussed. It is shown how to estimate the attenuation of the magnetic field from the normal magnetic modes for an approximate geometry. The estimate agrees satisfactorily with the attenuation measured with a commercial RF SQUID installed in the holder. The holder attenuates external magnetic fields by more than 10 to the 9th at the SQUID input. With the SQUID input shorted, the response to external fields is 0.00001 Phi(0)/G.

  12. SQUIDs: some limits to measurement

    NASA Astrophysics Data System (ADS)

    Gallop, John

    2003-12-01

    SQUIDs are used extensively across the world of precision measurement in physics and many other sciences, including earth science studies and medicine, providing some of the most precise measurements possible. The paper will discuss some of the limits to SQUID measurements which emerge in these various fields. One of the newer areas of interest is the use of SQUIDs to measure the properties of nanomagnetic particles or even single spins. This is driven by the needs of future ultra high density magnetic storage and quantum information processing. The paper will focus on this issue and will propose some hard limits as well as some means by which the present state-of-the-art may be extended towards those limits. This work is supported in part by the UK Department of Trade and Industry under project FQM131 of the Quantum Metrology Programme.

  13. Tracking Electromagnetic Energy With SQUIDs

    NASA Technical Reports Server (NTRS)

    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.

  14. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food... DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices 868.1670 Neon gas analyzer. (a) Identification. A neon gas analyzer is a device intended to measure the concentration of neon in a gas mixture exhaled by...

  15. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food... DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices 868.1670 Neon gas analyzer. (a) Identification. A neon gas analyzer is a device intended to measure the concentration of neon in a gas mixture exhaled by...

  16. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food... DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices 868.1670 Neon gas analyzer. (a) Identification. A neon gas analyzer is a device intended to measure the concentration of neon in a gas mixture exhaled by...

  17. 21 CFR 868.1670 - Neon gas analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neon gas analyzer. 868.1670 Section 868.1670 Food... DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices 868.1670 Neon gas analyzer. (a) Identification. A neon gas analyzer is a device intended to measure the concentration of neon in a gas mixture exhaled by...

  18. Small scale demand type neon liquefaction plant

    NASA Technical Reports Server (NTRS)

    Dube, W. P.; Slifka, A. J.; Bitsy, R. M.; Sparks, L. L.; Johnson, K. B.

    1990-01-01

    Low-temperature measurement of the thermal conductivity of insulating materials is generally made using a boil-off calorimetry technique involving liquid hydrogen (LH2). Liquid neon (LNe) has nearly the same normal boiling point as LH2, but has a much larger heat of vaporization, allowing extended run times. The main drawback of using LNe has been its excessive cost; $170.00 versus $1.50/l for LH2 (1989 prices). A neon liquefaction plant has been designed and constructed to capture, purify, and refrigerate the neon boil-off from calorimetry experiments. Recycling the neon reduces operating costs to approximately $20/l. The system consists of a purification section, a heat exchanger, LNe and LH2 storage dewars, and a fully automated control system. After purification, neon is liquified in the heat exchanger by LH2 flowing countercurrently through stainless steel cooling coils. Hydrogen flow is automatically adjusted to keep the neon at its normal saturation temperature, 27 K. The liquid neon is then stored in a dewar placed directly below the heat exchanger.

  19. Demonstrating Fluorescence with Neon Paper and Plastic

    NASA Astrophysics Data System (ADS)

    Birriel, Jennifer J.; Roe, Clarissa

    2015-09-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and office supply stores. We also employ violet-blue and green laser pointers as excitation sources. We conclude with a brief discussion of neon pigments in terms of the "day glow" or "daylight fluorescence" phenomenon.

  20. NEON Citizen Science: Planning and Prototyping

    NASA Astrophysics Data System (ADS)

    Newman, S. J.; Henderson, S.; Gardiner, L. S.; Ward, D.; Gram, W.

    2011-12-01

    The National Ecological Observatory Network (NEON) will be a national resource for ecological research and education. NEON citizen science projects are being designed to increase awareness and educate citizen scientists about the impacts of climate change, land-use change, and invasive species on continental-scale ecological processes as well as expand NEON data collection capacity by enabling laypersons to collect geographically distributed data. The citizen science area of the NEON web portal will enable citizen scientists to collect, contribute, interpret, and visualize scientific data, as well as access training modules, collection protocols and targeted learning experiences related to citizen science project topics. For NEON, citizen science projects are a means for interested people to interact with and contribute to NEON science. Investigations at vast spatial and temporal scales often require rapid acquisition of large amounts of data from a geographically distributed population of "human sensors." As a continental-scale ecological observatory, NEON is uniquely positioned to develop strategies to effectively integrate data collected by non-scientists into scientific databases. Ultimately, we plan to work collaboratively to transform the practice of science to include "citizens" or non-scientists in the process. Doing science is not limited to scientists, and breaking down the barriers between scientists and citizens will help people better understand the power of using science in their own decision making. In preparation for fully developing the NEON citizen science program, we are partnering with Project BudBurst (PBB), a citizen science project focused on monitoring plant phenology. The educational goals of PBB are to: (1) increase awareness of climate change, (2) educate citizen scientists about the impacts of climate change on plants and the environment, and (3) increase science literacy by engaging participants in the scientific process. Phenology was chosen as the focus of this citizen science campaign because it is a visible and comprehensible way of demonstrating the effects of climate change. In addition, plants are readily accessible in nearly every neighborhood and park, and wild area across the continent, so people can make observations whether they live near an inner city park or in the rural countryside. Recently, NEON developed data visualization tools for Project BudBurst to engage citizen science participants in "doing science" beyond data collection. By prototyping NEON citizen science through Project BudBurst, NEON is developing a better understanding of how to build a citizen science program that addresses areas of awareness, mastery, and leadership of scientific information like that which NEON will produce over the next 30 years.

  1. Cold SQUIDs and hot samples

    SciTech Connect

    Lee, T.S.C.

    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.

  2. Improved Sensing Coils for SQUIDs

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin; Hahn, Inseob; Eom, Byeong Ho

    2007-01-01

    An improvement in the design and fabrication of sensing coils of superconducting quantum interference device (SQUID) magnetometers has been proposed to increase sensitivity. It has been estimated that, in some cases, it would be possible to increase sensitivity by about half or to reduce measurement time correspondingly. The pertinent aspects of the problems of design and fabrication can be summarized as follows: In general, to increase the sensitivity of a SQUID magnetometer, it is necessary to maximize the magnetic flux enclosed by the sensing coil while minimizing the self-inductance of this coil. It is often beneficial to fabricate the coil from a thicker wire to reduce its self-inductance. Moreover, to optimize the design of the coil with respect to sensitivity, it may be necessary to shape the wire to other than a commonly available circular or square cross-section. On the other hand, it is not practical to use thicker superconducting wire for the entire superconducting circuit, especially if the design of a specific device requires a persistent-current loop enclosing a remotely placed SQUID sensor. It may be possible to bond a thicker sensing-coil wire to thinner superconducting wires leading to a SQUID sensor, but it could be difficult to ensure reliable superconducting connections, especially if the bonded wires are made of different materials. The main idea is to mold the sensing coil in place, to more nearly optimum cross sectional shape, instead of making the coil by winding standard pre-fabricated wire. For this purpose, a thin superconducting wire loop that is an essential part of the SQUID magnetometer would be encapsulated in a form that would serve as a mold. A low-melting-temperature superconducting metal (e.g., indium, tin, or a lead/tin alloy) would be melted into the form, which would be sized and shaped to impart the required cross section to the coil thus formed.

  3. Solar helium and neon in the Earth

    NASA Technical Reports Server (NTRS)

    Honda, M.; Mcdougall, I.; Patterson, D. B.

    1994-01-01

    Neon isotopic compositions in mantle-derived samples commonly are enriched in (20)Ne and (21)Ne relative to (22)Ne compared with atmospheric neon ((20)Ne/(22)Ne and (21)Ne/(22)Ne ratios in atmospheric neon are 9.8 and 0.029, respectively), together with significant primordial (3)He. Such results have been obtained on MORB's, intraplate plume-related oceanic island basalts, backarc basin basalts, mantle xenoliths, ancient diamonds and CO2 well gases (e.g., 1 - 8). The highest (20)Ne/(22)Ne ratio observed in MORB glasses (= 13.6 plus or minus 1.3 is close to the solar value (= 13.6, as observed in solar wind). In order to explain the enrichment of (20)Ne and (21)Ne relative to atmospheric neon for samples derived from the mantle, it is necessary to postulate the presence of at least two distinct non-atmospheric components. The two most likely candidates are solar and nucleogenic ((20)Ne/(22)Ne solar = 13.6 (21)Ne/(22)Ne solar = 0.032, (20)Ne/(22)Ne nucleogenic = 2.5 and (21)Ne/(22)Ne nucleogenic = 32). This is because solar neon is the only known component with a (20)Ne/(22)Ne ratio greater than both the atmospheric value and that observed in samples derived from the mantle. Nucleogenic neon is well known to elevate (21)Ne/(22)Ne ratios. Neon isotopic signatures observed in mantle-derived samples can be accounted for by mixing of the three neon end members: solar, nucleogenic and atmospheric.

  4. NEON Citizen Science: Planning and Prototyping (Invited)

    NASA Astrophysics Data System (ADS)

    Gram, W.

    2010-12-01

    The National Ecological Observatory Network (NEON) will be a national resource for ecological research and education. NEON citizen science projects are being designed to increase awareness and educate citizen scientists about the impacts of climate change, land-use change, and invasive species on continental-scale ecological processes as well as expand NEON data collection capacity by enabling laypersons to collect geographically distributed data. The citizen science area of the NEON web portal will enable citizen scientists to collect, contribute, interpret, and visualize scientific data, as well as access training modules, collection protocols and targeted learning experiences related to citizen science project topics. For NEON, citizen science projects are a means for interested people to interact with and contribute to NEON science. Investigations at vast spatial and temporal scales often require rapid acquisition of large amounts of data from a geographically distributed population of human sensors. As a continental-scale ecological observatory, NEON is uniquely positioned to develop strategies to effectively integrate data collected by non-scientists into scientific databases. Ultimately, we plan to work collaboratively to transform the practice of science to include citizens or non-scientists in the process. Doing science is not limited to scientists, and breaking down the barriers between scientists and citizens will help people better understand the power of using science in their own decision making. In preparation for fully developing the NEON citizen science program, we are partnering with Project BudBurst (PBB), a citizen science project focused on monitoring plant phenology. The educational goals of PBB are to: (1) increase awareness of climate change, (2) educate citizen scientists about the impacts of climate change on plants and the environment, and (3) increase science literacy by engaging participants in the scientific process. Phenology was chosen as the focus of this citizen science campaign because it is a visible and comprehensible way of demonstrating the effects of climate change. In addition, plants are readily accessible in nearly every neighborhood and park, and wild areas across the continent, so people can make observations whether they live near an inner city park or in the rural countryside. Recently, NEON built 3 web tools that enable users to visualize PBB data. The tools include a mapping function that displays selected PBB distributional data on a map, an animated map that shows green up through time and space, and a graphing tool that compares number of species flowering or leafing out with day length. This prototyping will help NEON better understand how to engage citizen science participants in doing science beyond data collection.

  5. Flying wings / flying fuselages

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Bauer, Steven X. S.

    2001-01-01

    The present paper has documented the historical relationships between various classes of all lifting vehicles, which includes the flying wing, all wing, tailless, lifting body, and lifting fuselage. The diversity in vehicle focus was to ensure that all vehicle types that map have contributed to or been influenced by the development of the classical flying wing concept was investigated. The paper has provided context and perspective for present and future aircraft design studies that may employ the all lifting vehicle concept. The paper also demonstrated the benefit of developing an understanding of the past in order to obtain the required knowledge to create future concepts with significantly improved aerodynamic performance.

  6. SQUID magnetometers for low-frequency applications

    SciTech Connect

    Ryhaenen, T.; Seppae, H. ); Ilmoniemi, R.; Knuutila, J. )

    1989-09-01

    The authors present a novel formulation for SQUID operation, which enables them to evaluate and compare the sensitivity and applicability of different devices. SQUID magnetometers for low-frequency applications are analyzed, taking into account the coupling circuits and electronics. They discuss nonhysteretic and hysteretic single-junction rf SQUIDs, but the main emphasis is on the dynamics, sensitivity, and coupling considerations of dc-SQUID magnetometers. A short review of current ideas on thin-film, dc-SQUID design presents the problems in coupling and the basic limits of sensitivity. The fabrication technology of tunnel-junction devices is discussed with emphasis on how it limits critical current densities, specific capacitances of junctions, minimum linewidths, conductor separations, etc. Properties of high-temperature superconductors are evaluated on the basis of recently published results on increased flux creep, low density of current carriers, and problems in fabricating reliable junctions. The optimization of electronics for different types of SQUIDs is presented. Finally, the most important low-frequency applications of SQUIDs in biomagnetism, metrology, geomagnetism, and some physics experiments demonstrate the various possibilities that state-of-the-art SQUIDs can provide.

  7. UHF SQUID-magnetometer at 77 K

    NASA Astrophysics Data System (ADS)

    Timofeev, Valery P.; Khvostov, Sergej S.; Tsoi, Georgy M.; Shnyrkov, Vladimir I.

    Using an interferometer made of the bulk YBaCuO ceramics a SQUID-based magnetometer has been designed. Magnetic flux sensitivity of the nitrogen-cooled UHF SQUID pumped at 390 MHz is found to be 510 -5? o/ Hz1/2 in the quasiwhite noise region. The energy sensitivity of the SQUID is about 2.610 -29 J/Hz which is by an order of magnitude higher than that of available HTS commercial SQUIDs. The receiving area of the quantization loop is 0.8mm in diameter resulting in the field sensitivity as high as 610 -14T/Hz1/2. On the basis of the device constructed, it is expected to design SQUID-magnetometers for nondestructive control, geophysical and biomagnetic researches.

  8. Biofunctional properties of enzymatic squid meat hydrolysate.

    PubMed

    Choi, Joon Hyuk; Kim, Kyung-Tae; Kim, Sang Moo

    2015-03-01

    Squid is one of the most important commercial fishes in the world and is mainly utilized or consumed as sliced raw fish or as processed products. The biofunctional activities of enzymatic squid meat hydrolysate were determined to develop value-added products. Enzymatic squid hydrolysate manufactured by Alcalase effectively quenched 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and hydrogen peroxide radical with IC50 values of 311, 3,410, and 111.5 ?g/mL, respectively. Angiotensin I-converting enzyme inhibitory activity of squid hydrolysate was strong with an IC50 value of 145.1 ?g/mL, while tyrosinase inhibitory activity with an IC50 value of 4.72 mg/mL was moderately low. Overall, squid meat hydrolysate can be used in food or cosmetic industries as a bioactive ingredient and possibly be used in the manufacture of seasoning, bread, noodle, or cosmetics. PMID:25866752

  9. Biofunctional Properties of Enzymatic Squid Meat Hydrolysate

    PubMed Central

    Choi, Joon Hyuk; Kim, Kyung-Tae; Kim, Sang Moo

    2015-01-01

    Squid is one of the most important commercial fishes in the world and is mainly utilized or consumed as sliced raw fish or as processed products. The biofunctional activities of enzymatic squid meat hydrolysate were determined to develop value-added products. Enzymatic squid hydrolysate manufactured by Alcalase effectively quenched 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and hydrogen peroxide radical with IC50 values of 311, 3,410, and 111.5 μg/mL, respectively. Angiotensin I-converting enzyme inhibitory activity of squid hydrolysate was strong with an IC50 value of 145.1 μg/mL, while tyrosinase inhibitory activity with an IC50 value of 4.72 mg/mL was moderately low. Overall, squid meat hydrolysate can be used in food or cosmetic industries as a bioactive ingredient and possibly be used in the manufacture of seasoning, bread, noodle, or cosmetics. PMID:25866752

  10. SQUID Multiplexers for Cryogenic Detector Arrays

    NASA Technical Reports Server (NTRS)

    Irwin, Kent; Beall, James; Deiker, Steve; Doriese, Randy; Duncan, William; Hilton, Gene; Moseley, S. Harvey; Reintsema, Carl; Stahle, Caroline; Ullom, Joel; Vale, Leila

    2004-01-01

    SQUID multiplexers make it possible to build arrays of thousands of cryogenic detectors with a manageable number of readout channels. We are developing time-division SQUID multiplexers based on Nb trilayer SQUIDs to read arrays of superconducting transition-edge sensors. Our first-generation, 8-channel SQUID multiplexer was used in FIBRE, a one-dimensional TES array for submillimeter astronomy. Our second-generation 32-pixel multiplexer, based on an improved architecture, has been developed for instruments including Constellation-X, SCUBA-2, and solar x-ray astronomy missions. SCUBA-2, which is being developed for the James Clerk Maxwell Telescope, will have more than 10,000 pixels. We are now developing a third-generation architecture based on superconducting hot-electron switches. The use of SQUID multiplexers in instruments operating at above 2 K will also be discussed.

  11. Low field electron paramagnetic resonance imaging with SQUID detection

    NASA Technical Reports Server (NTRS)

    Hahn, Inseob (Inventor); Day, Peter K. (Inventor); Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Cohen, Mark S. (Inventor)

    2012-01-01

    In one embodiment, a flux transformer with a gradiometer pickup coil is magnetically coupled to a SQUID, and a SQUID array amplifier comprising a plurality of SQUIDs, connected in series, is magnetically coupled to the output of the SQUID. Other embodiments are described and claimed.

  12. First demonstration of transcontinental SQUID magnetometry (Invited)

    NASA Astrophysics Data System (ADS)

    Fourie, C.; Febvre, P.; Pozzo di Borgo, E.; Waysand, G.; Gouws, D.; Saunderson, E.; Henry, S.; Gaffet, S.; Janse van Vuuren, L.; Lochner, E. T.; Matladi, T.; Kwisanga, C.

    2013-12-01

    We present the first simultaneous measurements from an ultra-sensitive dual-node transcontinental SQUID magnetometer network, available in real time on the internet. A three-axis low temperature SQUID sensor at LSBB Underground Research Laboratory, Rustrel, France (43.841 N, 5.484 E) and a two-axis high temperature SQUID sensor at SANSA Space Science in Hermanus, South Africa (34.424 S, 19.223 E), form the sensitive nodes of the network. Data are measured and GPS time stamped continuously at 125 Hz. The low-Tc SQUID at LSBB URL (known as a [SQUID]2 system) is inside a shielded steel capsule underneath 500 meters of karstic rock, which allows a low magnetic noise floor. The less sensitive high-Tc SQUID at SANSA Space Science is completely unshielded, and housed only in a magnetically neutral hut, 50 metres from a calibrated fluxgate node of the INTERMAGNET network, to protect it against the weather. The network, which is more sensitive than observatory fluxgate magnetometers, detects Earth's magnetosphere pulsations, Schumann waves, mesopause resonance, breathing modes of the Earth and oceanic swell. Our goal is further to extract directional or polarization information if earthquake precursors are observed again, as with the Sichuan-Wenchuan earthquake on 12 May 2008. In the medium term, we are exploring the possibility to extend the network with more spatially distributed SQUID sensors, such as at the South African National Antarctic Expedition's SANAE IV base in Antarctica.

  13. Aperture effects in squid jet propulsion.

    PubMed

    Staaf, Danna J; Gilly, William F; Denny, Mark W

    2014-05-01

    Squid are the largest jet propellers in nature as adults, but as paralarvae they are some of the smallest, faced with the inherent inefficiency of jet propulsion at a low Reynolds number. In this study we describe the behavior and kinematics of locomotion in 1 mm paralarvae of Dosidicus gigas, the smallest squid yet studied. They swim with hop-and-sink behavior and can engage in fast jets by reducing the size of the mantle aperture during the contraction phase of a jetting cycle. We go on to explore the general effects of a variable mantle and funnel aperture in a theoretical model of jet propulsion scaled from the smallest (1 mm mantle length) to the largest (3 m) squid. Aperture reduction during mantle contraction increases propulsive efficiency at all squid sizes, although 1 mm squid still suffer from low efficiency (20%) because of a limited speed of contraction. Efficiency increases to a peak of 40% for 1 cm squid, then slowly declines. Squid larger than 6 cm must either reduce contraction speed or increase aperture size to maintain stress within maximal muscle tolerance. Ecological pressure to maintain maximum velocity may lead them to increase aperture size, which reduces efficiency. This effect might be ameliorated by nonaxial flow during the refill phase of the cycle. Our model's predictions highlight areas for future empirical work, and emphasize the existence of complex behavioral options for maximizing efficiency at both very small and large sizes. PMID:24501132

  14. Dispersive Microwave Readout of NanoSQUIDs

    NASA Astrophysics Data System (ADS)

    Vijay, R.; Fathalizadeh, Aidin; Siddiqi, Irfan; Hatridge, Michael; Clarke, John

    2009-03-01

    Superconducting quantum interference devices (SQUIDs) based on Josephson tunnel junctions have long been used as sensitive magnetic flux detectors. NanoSQUIDs, which use submicron weak link junctions for enhanced flux coupling, are attractive candidates for magnetic measurements of molecules. We present a novel method for nanoSQUID readout which involves embedding the SQUID in a superconducting transmission line cavity operating at microwave frequency. The magnetic flux dependence of the total SQUID inductance modulates the cavity resonant frequency; these frequency changes are determined using microwave reflectometry. This dispersive microwave measurement allows detection of changes in magnetic flux at submicrosecond timescales without creating dissipation in the vicinity of the molecule. Moreover, we can exploit the Josephson nonlinearity of the nanoSQUID for bifurcation amplification to enhance sensitivity. Optimization of the nanoSQUID design and cavity parameters for maximizing detector sensitivity and bandwidth is discussed. We also discuss the various sources of noise in this measurement scheme and how to minimize their impact. This work is supported by AFOSR and USDOE.

  15. 1 MHz bandwidth true NMR SQUID amplifier

    NASA Astrophysics Data System (ADS)

    Thomasson, S. L.; Gould, C. M.

    1995-10-01

    We have developed an integrated dc SQUID magnetometer with additional positive feedback (APF) for low frequency true NMR applications. The APF scheme allows direct coupled read out from the SQUID to room temperature electronics and eliminates the need for the conventional modulation scheme, thereby greatly simplifying the flux-locked loop electronics. We have configured our SQUID system for the specific needs of sensitive NMR measurements which include large bandwidth and high slew rate. We have achieved a bandwidth of 1.2 MHz and a slew rate greater than 105?0/s for frequencies above 10 kHz.

  16. ASA's Chandra Neon Discovery Solves Solar Paradox

    NASA Astrophysics Data System (ADS)

    2005-07-01

    NASA's Chandra X-ray Observatory survey of nearby sun-like stars suggests there is nearly three times more neon in the sun and local universe than previously believed. If true, this would solve a critical problem with understanding how the sun works. "We use the sun to test how well we understand stars and, to some extent, the rest of the universe," said Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "But in order to understand the sun, we need to know exactly what it is made of," he added. It is not well known how much neon the sun contains. This is critical information for creating theoretical models of the sun. Neon atoms, along with carbon, oxygen and nitrogen, play an important role in how quickly energy flows from nuclear reactions in the sun's core to its edge, where it then radiates into space. Chandra X-ray Spectrum of II Pegasi Chandra X-ray Spectrum of II Pegasi The rate of this energy flow determines the location and size of a crucial stellar region called the convection zone. The zone extends from near the sun's surface inward approximately 125,000 miles. The zone is where the gas undergoes a rolling, convective motion much like the unstable air in a thunderstorm. "This turbulent gas has an extremely important job, because nearly all of the energy emitted at the surface of the sun is transported there by convection," Drake said. The accepted amount of neon in the sun has led to a paradox. The predicted location and size of the solar convection zone disagree with those deduced from solar oscillations. Solar oscillations is a technique astronomers previously relied on to probe the sun's interior. Several scientists have noted the problem could be fixed if the abundance of neon is in fact about three times larger than currently accepted. Attempts to measure the precise amount of neon in the Sun have been frustrated by a quirk of nature; neon atoms in the Sun give off no signatures in visible light. However, in a gas heated to millions of degrees, neon shines brightly in X-rays. Stars like the sun are covered in this super-heated gas that is betrayed by the white corona around them during solar eclipses. However, observations of the sun's corona are very difficult to analyze. Labeled Illustration of Convection in Sun-like Star Labeled Illustration of Convection in Sun-like Star To probe the neon content, Drake and his colleague Paola Testa of the Massachusetts Institute of Technology in Cambridge, Mass., observed 21 sun-like stars within a distance of 400 light years from Earth. These local stars and the sun should contain about the same amount of neon when compared to oxygen. However, these close stellar kin were found to contain on average almost three times more neon than is believed for the sun. "Either the sun is a freak in its stellar neighborhood, or it contains a lot more neon than we think," Testa said. These Chandra results reassured astronomers the detailed physical theory behind the solar model is secure. Scientists use the model of the sun as a basis for understanding the structure and evolution of other stars, as well as many other areas of astrophysics. "If the higher neon abundance measured by Drake and Testa is right, then it is a simultaneous triumph for Chandra and for the theory of how stars shine," said John Bahcall of the Institute for Advanced Study, Princeton, N.J. Bahcall is an expert in the field who was not involved in the Chandra study. Drake is lead author of the study published in this week's issue of the journal Nature. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

  17. Reef Squid at USGS Monitoring Station

    USGS Multimedia Gallery

    A curious reef squid hovers over a calcification-monitoring station used to measure calcification rates to determine impact of ocean acidification on coral growth at Fowey Rocks Light Reef in Biscayne National Park.  ...

  18. Genetic identification of a rare record of Ommastrephes Bartramii (Cephalopoda: Ommastrephidae) from the Eastern Adriatic Sea.

    PubMed

    Franjevi?, Damjan; Skaramuca, Daria; Katavi?, Vedran; Rajevi?, Nives; Skaramuca, Boko

    2015-01-01

    The neon flying squid Ommastrephes bartramii Lesueur, 1821 belongs to the Ommastrephidae, Cephalopoda family. The family Ommastrephidae (Mollusca: Cephalopoda) includes many commercially important species, dispersed around the world. The Ommastrephidae family is conventionally divided into three subfamilies (Illicinae, Todarodinae, and Ommastrephinae). We report a specimen of neon flying squid caught in the winter 2013 at Luka ipanska, Island of ipan, Croatia and identified at the genetic level using the standard mitochondrial COI barcode region. This record represents the first genetic identification of a neon flying squid from the Adriatic Sea. PMID:26103681

  19. Ultralow Temperature Operation of dc SQUID Amplifiers

    NASA Astrophysics Data System (ADS)

    Thomasson, S. L.; Gould, C. M.

    1998-03-01

    Nuclear magnetic resonance (NMR) experiments at ultralow temperatures place high demands on superconducting quantum interference device (SQUID) amplifiers. We have developed a suitable direct-coupled readout SQUID electronics system, which utilizes additional positive feedback (APF), and have achieved a system bandwidth of 5 MHz, maximum slew rate of 1.3 x 10^7 ?_0/s at 14 kHz, and a white noise level of 3.4 ? ?0 / ? ( Hz ). High coupling efficiencies for our NMR system are difficult to achieve owing to the requisite large physical separation in our cryostats between the SQUID at 4.2 K and the experiment at T ~= 1 mK. We have investigated improving the signal to noise ratio by using a low noise series array of dc SQUIDs, and by placing the SQUID amplifier closer to the ultralow temperature experiment, thereby reducing parasitic lead inductances. We will discuss how we have configured our SQUID amplifiers for operation at T << 1 K.

  20. Muon transfer from hot muonic hydrogen atoms to neon

    SciTech Connect

    Jacot-Guillarmod, R. . Inst. de Physique); Bailey, J.M. ); Beer, G.A.; Knowles, P.E.; Mason, G.R.; Olin, A. ); Beveridge, J.L.; Marshall, G.M.; Brewer, J.H.; Forster, B.M. ); Huber, T.M. ); Kammel, P.; Zmeskal, J.

    1992-01-01

    A negative muon beam has been directed on adjacent solid layers of hydrogen and neon. Three targets differing by their deuterium concentration were investigated. Muonic hydrogen atoms can drift to the neon layer where the muon is immediately transferred. The time structure of the muonic neon X-rays follows the exponential law with a disappearance rate corresponding to the one of [mu][sup [minus]p] atoms in each target. The rates [lambda][sub pp[mu

  1. 40 K Liquid Neon Energy Storage Unit

    NASA Astrophysics Data System (ADS)

    Martins, D.; Sousa, P. Borges de; Catarino, I.; Bonfait, G.

    A thermal Energy Storage Unit (ESU) could be used to attenuate inherent temperature fluctuations of a cold finger, either from a cryocooler working or due to suddenly incoming heat bursts. An ESU directly coupled to the cold source acts as a thermal buffer temporarily increasing its cooling capacity and providing a better thermal stability of the cold finger ("Power Booster mode"). The energy storage units presented here use an enthalpy reservoir based on the high latent heat of the liquid-vapour transition of neon in the temperature range 38 - 44 K to store up to 900 J, and that uses a 6 liters expansion volume at room temperature in order to work as a closed system. Experimental results in the power booster mode are described: in this case, the liquid neon cell was directly coupled to the cold finger of the working cryocooler, its volume (?12 cm3) allowing it to store 450 J at around 40 K. 10 W heat bursts were applied, leading to liquid evaporation, with quite reduced temperature changes. The liquid neon reservoir can also work as a temporary cold source to be used after stopping the cryocooler, allowing for a vibration-free environment. In this case the enthalpy reservoir implemented (?24 cm3) was linked to the cryocooler cold finger through a gas-gap heat switch for thermal coupling/decoupling of the cold finger. We show that, by controlling the enthalpy reservoir's pressure, 900 Jcan be stored at a constant temperature of 40 K as in a triple-point ESU.

  2. Visually guided eye growth in the squid.

    PubMed

    Turnbull, Philip R K; Backhouse, Simon; Phillips, John R

    2015-09-21

    Eyes with refractive error have reduced visual acuity and are rarely found in the wild. Vertebrate eyes possess a visually guided emmetropisation process within the retina which detects the sign of defocus, and regulates eye growth to align the retina at the focal plane of the eye's optical components to avoid the development of refractive error, such as myopia, an increasing problem in humans. However, the vertebrate retina is complex, and it is not known which of the many classes of retinal neurons are involved. We investigated whether the camera-type eye of an invertebrate, the squid, displays visually guided emmetropisation, despite squid eyes having a simple photoreceptor-only retina. We exploited inherent longitudinal chromatic aberration (LCA) to create disparate focal lengths within squid eyes. We found that squid raised under orange light had proportionately longer eyes and more myopic refractions than those raised under blue light, and when switched between wavelengths, eye size and refractive status changed appropriately within a few days. This demonstrates that squid eye growth is visually guided, and suggests that the complex retina seen in vertebrates may not be required for emmetropisation. PMID:26394098

  3. Dietary protein source and level alters growth in neon tetras.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutritional studies for aquarium fish like the neon tetra are sparse in comparison with those for food fish. To determine the optimum dietary protein level and source for growth of neon tetras, diets were formulated to contain 25, 35, 45 and 55% dietary protein from either marine animal protein or ...

  4. Flux modulation scheme for direct current SQUID readout revisited

    NASA Astrophysics Data System (ADS)

    Hong, Tao; Wang, Hai; Zhang, Yi; Krause, Hans-Joachim; Braginski, Alex I.; Xie, Xiaoming; Offenhäusser, Andreas; Jiang, Mianheng

    2016-02-01

    The flux modulation scheme (FMS) is the standard readout technique of dc SQUIDs, where a step-up transformer links the SQUID to the preamplifier. The transformer's primary winding shunts the SQUID via a large capacitor while the secondary winding connects it to the preamplifier. A modulation flux having a frequency of typically 100 kHz generates an ac voltage across the SQUID, stepped up by the transformer. The SQUID with FMS is customarily operated in the current bias mode, because a constant dc bias current flows only through the SQUID due to the capacitor isolation. With FMS, however, the transformer ac shunts the SQUID so that in reality the operating mode is neither purely current-biased nor voltage-biased but rather nominal current-biased or "mixed biased." Our objective is to experimentally investigate the consequences of ac shunting of the dc SQUID in FMS and the transformer's transfer characteristics. For different shunt values we measure the change in the SQUID bias current due to the ac shunt using another SQUID in the two-stage readout scheme, and simultaneously monitor the SQUID output voltage signal. We then explain our measurements by a simplified graphic analysis of SQUID intrinsic current-voltage (I-V) characteristics. Since the total current flowing through the SQUID is not constant due to the shunting effect of the transformer, the amplitude of SQUID flux-to-voltage characteristics V(Φ) is less as compared to the direct readout scheme (DRS). Furthermore, we analyze and compare V(Φ) obtained by DRS and FMS. We show that in FMS, the transfer characteristics of the SQUID circuit also depend on the isolation capacitance and the dynamic resistance of the SQUID.

  5. Genetic determinants of swimming motility in the squid light-organ symbiont Vibrio fischeri

    PubMed Central

    Brennan, Caitlin A; Mandel, Mark J; Gyllborg, Mattias C; Thomasgard, Krista A; Ruby, Edward G

    2013-01-01

    Abstract Bacterial flagellar motility is a complex cellular behavior required for the colonization of the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes, by the beneficial bioluminescent symbiont Vibrio fischeri. We characterized the basis of this behavior by performing (i) a forward genetic screen to identify mutants defective in soft-agar motility, as well as (ii) a transcriptional analysis to determine the genes that are expressed downstream of the flagellar master regulator FlrA. Mutants with severe defects in soft-agar motility were identified due to insertions in genes with putative roles in flagellar motility and in genes that were unexpected, including those predicted to encode hypothetical proteins and cell divisionrelated proteins. Analysis of mutants for their ability to enter into a productive symbiosis indicated that flagellar motility mutants are deficient, while chemotaxis mutants are able to colonize a subset of juvenile squid to light-producing levels. Thirty-three genes required for normal motility in soft agar were also downregulated in the absence of FlrA, suggesting they belong to the flagellar regulon of V.fischeri. Mutagenesis of putative paralogs of the flagellar motility genes motA motB, and fliL revealed that motA1 motB1, and both fliL1 and fliL2, but not motA2 and motB2, likely contribute to soft-agar motility. Using these complementary approaches, we have characterized the genetic basis of flagellar motility in V.fischeri and furthered our understanding of the roles of flagellar motility and chemotaxis in colonization of the juvenile squid, including identifying 11 novel mutants unable to enter into a productive light-organ symbiosis. PMID:23907990

  6. Squid Pax-6 and eye?development

    PubMed Central

    Tomarev, Stanislav I.; Callaerts, Patrick; Kos, Lidia; Zinovieva, Rina; Halder, Georg; Gehring, Walter; Piatigorsky, Joram

    1997-01-01

    Pax-6 in vertebrates and its homolog eyeless in Drosophila are known to be essential for eye development. Here we investigate the role of Pax-6 in eye development in another major systematic group, molluscs. We demonstrate that alternatively spliced RNAs derived from a single Pax-6 gene in the squid (Loligo opalescens) are expressed in the embryonic eye, olfactory organ, brain, and arms. Despite significant sequence differences between squid Pax-6 and Drosophila eyeless in the region outside the paired- and homeodomains, squid Pax-6 is able to induce the formation of ectopic eyes in Drosophila. Our results support the idea that Pax-6 related genes are necessary for eye and olfactory system formation throughout the animal kingdom. PMID:9122210

  7. Damage accumulation in neon implanted silicon

    SciTech Connect

    Oliviero, E.; Peripolli, S.; Amaral, L.; Fichtner, P. F. P.; Beaufort, M. F.; Barbot, J. F.; Donnelly, S. E.

    2006-08-15

    Damage accumulation in neon-implanted silicon with fluences ranging from 5x10{sup 14} to 5x10{sup 16} Ne cm{sup -2} has been studied in detail. As-implanted and annealed samples were investigated by Rutherford backscattering spectrometry under channeling conditions and by transmission electron microscopy in order to quantify and characterize the lattice damage. Wavelength dispersive spectrometry was used to obtain the relative neon content stored in the matrix. Implantation at room temperature leads to the amorphization of the silicon while a high density of nanosized bubbles is observed all along the ion distribution, forming a uniform and continuous layer for implantation temperatures higher than 250 deg.C. Clusters of interstitial defects are also present in the deeper part of the layer corresponding to the end of range of ions. After annealing, the samples implanted at temperatures below 250 deg.C present a polycrystalline structure with blisters at the surface while in the other samples coarsening of bubbles occurs and nanocavities are formed together with extended defects identified as (311) defects. The results are discussed in comparison to the case of helium-implanted silicon and in the light of radiation-enhanced diffusion.

  8. Diffusion of neon in white dwarf stars.

    PubMed

    Hughto, J; Schneider, A S; Horowitz, C J; Berry, D K

    2010-12-01

    Sedimentation of the neutron rich isotope 22Ne may be an important source of gravitational energy during the cooling of white dwarf stars. This depends on the diffusion constant for 22Ne in strongly coupled plasma mixtures. We calculate self-diffusion constants D(i) from molecular dynamics simulations of carbon, oxygen, and neon mixtures. We find that D(i) in a mixture does not differ greatly from earlier one component plasma results. For strong coupling (coulomb parameter Γ> few), D(i) has a modest dependence on the charge Z(i) of the ion species, D(i)∝Z(i)(-2/3). However, D(i) depends more strongly on Z(i) for weak coupling (smaller Γ). We conclude that the self-diffusion constant D(Ne) for 22Ne in carbon, oxygen, and neon plasma mixtures is accurately known so that uncertainties in D(Ne) should be unimportant for simulations of white dwarf cooling. PMID:21230741

  9. Three-Junction SQUID Rocking Ratchet

    NASA Astrophysics Data System (ADS)

    Sterck, A.; Kleiner, R.; Koelle, D.

    2005-10-01

    We investigate three-junction SQUIDs which show voltage rectification if biased with an ac current drive with zero mean value. The Josephson phase across the SQUID experiences an effective ratchet potential, and the device acts as an efficient rocking ratchet, as demonstrated experimentally for adiabatic and nonadiabatic drive frequencies. For high-frequency drives the rectified voltage is quantized due to synchronization of the phase dynamics with the external drive. The experimental data are in excellent agreement with numerical simulations including thermal fluctuations.

  10. Flying Cars

    NASA Technical Reports Server (NTRS)

    Crow, Steven

    1996-01-01

    Flying cars have nearly mythical appeal to nonpilots, a group that includes almost the whole human race. The appeal resides in the perceived utility of flying cars, vehicles that offer portal-to-portal transportation, yet break the bonds of road and traffic and travel freely through the sky at the drivers will. Part of the appeal is an assumption that flying cars can be as easy to fly as to drive. Flying cars have been part of the dream of aviation since the dawn of powered flight. Glenn Curtiss built, displayed, and maybe even flew a flying car in 1917, the Curtiss Autoplane. Many roadable airplanes were built in the 1930's, like the Waterman Arrowbile and the Fulton Airphibian. Two flying cars came close to production in the early 1950's. Ted Hall built a series of flying cars culminating in the Convaircar, sponsored by Consolidated Vultee, General Motors, and Hertz. Molt Taylor built and certified his Aerocar, and Ford came close to producing them. Three Aerocars are still flyable, two in museums in Seattle and Oshkosh, and the third owned and flown by Ed Sweeny. Flying cars do have problems, which so far have prevented commercial success. An obvious problem is complexity of the vehicle, the infrastructure, or both. Another is the difficulty of matching low power for normal driving with high power in flight. An automobile uses only about 20 hp at traffic speeds, while a personal airplane needs about 160 hp at speeds typical of flight. Many automobile engines can deliver 160 hp, but not for very long. A more subtle issue involves the drag of automobiles and airplanes. A good personal airplane can fly 30 miles per gallon of fuel at 200 mph. A good sports car would need 660 hp at the same speed and would travel only 3 miles per gallon. The difference is drag area, about 4.5 sq ft for the automobile and 1.4 sq ft for the airplane. A flying car better have the drag area of the airplane, not the car!

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

    NASA Astrophysics Data System (ADS)

    Tabatabaei, Mahdi; Bahadır Olcay, Ali; Gokçen, Gökhan; Heperkan, Hasan A.

    2015-05-01

    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.

  12. Multichannel SQUID systems for brain research

    SciTech Connect

    Ahonen, A.I.; Hamalainen, M.S.; Kajola, M.J.; Knuutila, J.E.F.; Lounasmaa, O.V.; Simola, J.T.; Vilkman, V.A. . Low Temperature Lab.); Tesche, C.D. . Thomas J. Watson Research Center)

    1991-03-01

    This paper reviews basis principles of magnetoencephalography (MEG) and neuromagnetic instrumentation. The authors' 24-channel system, based on planar gradiometer coils and dc-SQUIDs, is then described. Finally, recent MEG-experiments on human somatotopy and focal epilepsy, carried out in the authors' laboratory, are presented.

  13. Scanning SQUID susceptometry of a paramagnetic superconductor

    NASA Astrophysics Data System (ADS)

    Kirtley, J. R.; Kalisky, B.; Bert, J. A.; Bell, C.; Kim, M.; Hikita, Y.; Hwang, H. Y.; Ngai, J. H.; Segal, Y.; Walker, F. J.; Ahn, C. H.; Moler, K. A.

    2012-06-01

    Scanning SQUID susceptometry images the local magnetization and susceptibility of a sample. By accurately modeling the SQUID signal we can determine physical properties such as the penetration depth and permeability of superconducting samples. We calculate the scanning SQUID susceptometry signal for a superconducting slab of arbitrary thickness with isotropic London penetration depth ? on a nonsuperconducting substrate, where both slab and substrate can have a paramagnetic response that is linear in the applied field. We derive analytical approximations to our general expression in a number of limits. Using our results, we fit experimental susceptibility data as a function of the sample-sensor spacing for three samples: (1) ?-doped SrTiO3, which has a predominantly diamagnetic response, (2) a thin film of LaNiO3, which has a predominantly paramagnetic response, and (3) the two-dimensional electron layer at a SrTiO3/LaAlO3 interface, which exhibits both types of response. These formulas will allow the determination of the concentrations of paramagnetic spins and superconducting carriers from fits to scanning SQUID susceptibility measurements.

  14. Squid Dissection: From Pen to Ink.

    ERIC Educational Resources Information Center

    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)

  15. One Period of Exploration with the Squid.

    ERIC Educational Resources Information Center

    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)

  16. Practical dc SQUID system: Devices and electronics

    NASA Astrophysics Data System (ADS)

    Zhang, Guofeng; Zhang, Yi; Hong, Tao; Wang, Hai; Krause, Hans-Joachim; Xie, Xiaoming

    2015-11-01

    In order to set up a liquid helium-cooled practical dc SQUID system with acceptable noise figure, we employ a weakly damped dc SQUID with a large flux-to-voltage transfer coefficient ∂V/∂V in a direct readout scheme (DRS) without flux modulation. Two preamplifiers are utilized: (1) AD 797 for a so-called "single chip readout electronics" (SCRE); (2) 6 parallel-connected bipolar transistors (PCBT). The latter reduces the preamplifier voltage noise Vn but increases its current noise In, which plays a leading role in the system low-frequency noise. We introduce a current feedback circuit (CFC) consisting of an inductor Li coupled to the SQUID with mutual inductance Mi to improve the noise performance. In this work, the preamplifier In contribution and CFC are analyzed. To evaluate the In suppression with CFC, two criteria are presented. Furthermore, we establish a dimensionless parameter ξ to describe CFC quantitatively. The system noise is compared with and without CFC using the two preamplifiers. For a dc SQUID with a loop inductance of 350 pH, an intrinsic noise of about 5 μV0/√Hz and a corner frequency at 2 Hz are measured using PCBT with CFC.

  17. The prospects of a subnanometer focused neon ion beam.

    PubMed

    Rahman, F H M; McVey, Shawn; Farkas, Louis; Notte, John A; Tan, Shida; Livengood, Richard H

    2012-01-01

    The success of the helium ion microscope has encouraged extensions of this technology to produce beams of other ion species. A review of the various candidate ion beams and their technical prospects suggest that a neon beam might be the most readily achieved. Such a neon beam would provide a sputtering yield that exceeds helium by an order of magnitude while still offering a theoretical probe size less than 1-nm. This article outlines the motivation for a neon gas field ion source, the expected performance through simulations, and provides an update of our experimental progress. PMID:21796647

  18. Muon transfer from hot muonic hydrogen atoms to neon

    SciTech Connect

    Jacot-Guillarmod, R.; Bailey, J.M.; Beer, G.A.; Knowles, P.E.; Mason, G.R.; Olin, A.; Beveridge, J.L.; Marshall, G.M.; Brewer, J.H.; Forster, B.M.; Huber, T.M.; Kammel, P.; Zmeskal, J.; Kunselman, A.R.; Petitjean, C.

    1992-12-31

    A negative muon beam has been directed on adjacent solid layers of hydrogen and neon. Three targets differing by their deuterium concentration were investigated. Muonic hydrogen atoms can drift to the neon layer where the muon is immediately transferred. The time structure of the muonic neon X-rays follows the exponential law with a disappearance rate corresponding to the one of {mu}{sup {minus}p} atoms in each target. The rates {lambda}{sub pp{mu}} and {lambda}{sub pd} can be extracted.

  19. Collision induced light scattering by gaseous neon

    NASA Astrophysics Data System (ADS)

    Rachet, F.; Chrysos, M.; Lothon, G.; Moszynski, R.; Milet, A.

    2002-12-01

    Binary collision induced light scattering by gaseous room temperature neon has been both experimentally and theoretically studied. Our experimental scattering cross sections have been calibrated on an absolute scale. The anisotropic spectrum and the depolarization ratio have been measured over the 5-300 cm-1 frequency domain, whereas the isotropic spectrum has been recorded over the domain 125-300 cm-1. In comparison with any previous work in the topic, our measurements provide a substantial extension of the probed far wing. An exhaustive study of the light scattering process has been made from the theoretical/numerical viewpoint also. This has been made possible by quantum mechanically computing scattering intensities via a rigorous numerical treatment (previously developed by the authors) accounting both for free Ne pairs and for stable Ne2 diatoms, which has been coupled to a novel ab initio incremental polarizability model based on Symmetry Adapted Perturbation Theory.

  20. Choreography of the squid's "nuptial dance".

    PubMed

    Sauer, W H; Roberts, M J; Lipinski, M R; Smale, M J; Hanlon, R T; Webber, D M; O'Dor, R K

    1997-04-01

    A mass spawning of squid resembles, at first glance, a chaotic "nuptial dance" (1). But for the first time, we have applied 3-D, radio-linked acoustic positioning (RAP) to this confusing process, and our early results now reveal a choreography that is, in fact, well organized in time and space. Remote tracking with RAP of individual Loligo vulgaris reynaudii off South Africa has provided insights into the daily sequence of behaviours that lead these animals to aggregate for sexual selection. Each dawn, the squid navigate for several kilometers, towards the shore, to small, well-defined zones near egg beds on the substrate. After several hours of circling above the egg beds, a pelagic, 3-D lek-like aggregation of large males forms: females are drawn in, and the aggregation condenses as the females and males pair, mate, and lay eggs. Smaller "sneaker males" remain on the periphery of the mating arena and, from this station, attempt extra-pair copulations (EPCs). The mating system of squids is thus unexpectedly complex, rivaling those of mammals and birds (2, 3). Commercial squid-jigging fishermen in South Africa have recently been attracted to the spawning grounds, and they have been successful. Moreover, their activities may be selective for large males. Thus, attention should be devoted to ensuring that such targeted fishing does not alter the characteristics of squid population genetics. Remote tracking and video observations, in combination with genetic analyses, may offer a new opportunity to monitor mating effort and reproductive success, and thus to manage the fishery. PMID:9145496

  1. Chromogenic behaviors of the Humboldt squid (Dosidicus gigas) studied in situ with an animal-borne video package.

    PubMed

    Rosen, Hannah; Gilly, William; Bell, Lauren; Abernathy, Kyler; Marshall, Greg

    2015-01-15

    Dosidicus gigas (Humboldt or jumbo flying squid) is an economically and ecologically influential species, yet little is known about its natural behaviors because of difficulties in studying this active predator in its oceanic environment. By using an animal-borne video package, National Geographic's Crittercam, we were able to observe natural behaviors in free-swimming D. gigas in the Gulf of California with a focus on color-generating (chromogenic) behaviors. We documented two dynamic displays without artificial lighting at depths of up to 70 m. One dynamic pattern, termed 'flashing' is characterized by a global oscillation (2-4 Hz) of body color between white and red. Flashing was almost always observed when other squid were visible in the video frame, and this behavior presumably represents intraspecific signaling. Amplitude and frequency of flashing can be modulated, and the phase relationship with another squid can also be rapidly altered. Another dynamic display termed 'flickering' was observed whenever flashing was not occurring. This behavior is characterized by irregular wave-like activity in neighboring patches of chromatophores, and the resulting patterns mimic reflections of down-welled light in the water column, suggesting that this behavior may provide a dynamic type of camouflage. Rapid and global pauses in flickering, often before a flashing episode, indicate that flickering is under inhibitory neural control. Although flashing and flickering have not been described in other squid, functional similarities are evident with other species. PMID:25609785

  2. Acceleration of neon pellets to high speeds for fusion applications

    SciTech Connect

    Combs, S.K.; Love, T.L.; Jernigan, T.C.; Milora, S.L.; Frattolillo, A.; Migliori, S.

    1996-03-01

    The injection of impurity pellets into the plasmas of tokamak fusion reactors has been proposed as a technique to lessen the deleterious effects of plasma disruptions. Equipment and techniques that were previously developed for pneumatic hydrogen pellet injection systems and used for plasma fueling applications were employed for a limited experimental study with neon pellets. Isotopic hydrogen pellets doped with neon have previously been used for injection into fusion plasmas to study impurity particle transport, and pure neon pellets are applicable for disruption studies. Using a repeating pneumatic injector in the laboratory, it was found that the formation and acceleration of 2.7-mm-diam neon pellets were relatively straightforward; reliable operation was demonstrated with both a single- and a two-stage light gas gun, including velocities of {approximately}700 m/s with a single-stage injector and up to 1740 m/s with a two-stage injector. Based on the operating sequences and successful tests demonstrated in the laboratory experiments, a three-barrel repeating pneumatic injector installed on the DIII-D tokamak was equipped with the necessary components for neon operation and has been used in initial disruption experiments with 1.8-mm-diam neon pellets. {copyright} {ital 1996 American Institute of Physics.}

  3. Practical SQUID Instrument for Nondestructive Testing

    NASA Technical Reports Server (NTRS)

    Tralshawala, N.; Claycomb, J. R.; Miller, John H., Jr.

    1997-01-01

    We report on the development of a scanning eddy-current imaging system designed to detect deep subsurface flaws in conducting materials. A high transition temperature (high-T c) superconducting quantum interference device (SQUID) magnetometer is employed to provide the required sensitivity at low frequencies, while a combination of small cylindrical high-Tc superconducting and A-metal shields enable the instrument to be scanned in a magnetically noisy environment, rather than the object under test. The shields are arranged to prevent unwanted excitation and ambient noise fields from reaching the SQUID, and to enhance spatial resolution and minimize undesirable edge effects. Thus far, the instrument has successfully detected cracks and pits through 10 layers of aluminum, with a combined thickness of 5 cm at room temperature.

  4. Low Temperature SQUID for NDE Applications

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz (Technical Monitor); Selim, Raouf

    2003-01-01

    We have developed a low temperature SuperConducting Quantum Interference Device - SQUID measurement system for detection of defects deep under the surface of aluminum structures using eddy current techniques. The system uses a two dimensional planar inducer with two different excitation frequencies to induce a current in the sample. We have developed a data analysis software program that enabled us to distinguish between round defects (holes), straight defects (slots) and slots close to holes simulating cracks starting from rivets in aluminum structures. We were able to detect defects that are 8mm below the surface. We have also measured the change in phase of the detected signal as a function of depth of the defect. This relationship can be used to determine the depth of hidden flaws. Using this analysis software with the high temperature SQUID system at NASA Langley we were able to detect slots close to holes in layered aluminum sample.

  5. Supersensitive SQUID/magnetostrictor detecting system

    SciTech Connect

    Golovashkin, Aleksander I; Zherikhina, L N; Tskhovrebov, Andrei M; Izmailov, G N

    2012-12-31

    It is shown that using the state-of-the-art quantum interferometer (SQUID) with the resolution 10{sup -6} {Phi}{sub 0} Hz{sup -1/2} = 2.07 Multiplication-Sign 10{sup -21} Wb Hz{sup -1/2}, coupled to a magnetostrictor, playing the role of tensomagnetic transducer, it is possible to construct a system for detecting pressure variations with the ultimate sensitivity of 10{sup -13} Pa Hz{sup -1/2} and for measuring specific elongation with the sensitivity of 10{sup -24} Hz{sup -1/2}. The analysis of physical grounds of the inverse magnetostriction effect demonstrates concrete ways to essentially higher efficiency of tensomagnetic conversion. The estimates performed demonstrate the possibility of using the SQUID/magnetostrictor system as a detector of gravitational waves. Other possibilities of using this system for solving both fundamental and applied problems are also considered. (experimental techniques)

  6. Light-curve Analysis of Neon Novae

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Kato, Mariko

    2016-01-01

    We analyzed light curves of five neon novae, QU Vul, V351 Pup, V382 Vel, V693 CrA, and V1974 Cyg, and determined their white dwarf (WD) masses and distance moduli on the basis of theoretical light curves composed of free-free and photospheric emission. For QU Vul, we obtained a distance of d ˜ 2.4 kpc, reddening of E(B - V) ˜ 0.55, and WD mass of MWD = 0.82-0.96 {M}⊙ . This suggests that an oxygen-neon WD lost a mass of more than ˜ 0.1 {M}⊙ since its birth. For V351 Pup, we obtained d˜ 5.5 {{kpc}}, E(B-V)˜ 0.45, and {M}{{WD}}=0.98-1.1 {M}⊙ . For V382 Vel, we obtained d˜ 1.6 {{kpc}}, E(B-V)˜ 0.15, and {M}{{WD}}=1.13-1.28 {M}⊙ . For V693 CrA, we obtained d˜ 7.1 {{kpc}}, E(B-V)˜ 0.05, and {M}{{WD}}=1.15-1.25 {M}⊙ . For V1974 Cyg, we obtained d˜ 1.8 {{kpc}}, E(B-V)˜ 0.30, and {M}{{WD}}=0.95-1.1 {M}⊙ . For comparison, we added the carbon-oxygen nova V1668 Cyg to our analysis and obtained d˜ 5.4 {{kpc}}, E(B-V)˜ 0.30, and {M}{{WD}}=0.98-1.1 {M}⊙ . In QU Vul, photospheric emission contributes 0.4-0.8 mag at most to the optical light curve compared with free-free emission only. In V351 Pup and V1974 Cyg, photospheric emission contributes very little (0.2-0.4 mag at most) to the optical light curve. In V382 Vel and V693 CrA, free-free emission dominates the continuum spectra, and photospheric emission does not contribute to the optical magnitudes. We also discuss the maximum magnitude versus rate of decline relation for these novae based on the universal decline law.

  7. Coupled Serial and Parallel Non-uniform SQUIDs

    NASA Astrophysics Data System (ADS)

    Longhini, Patrick; Berggren, Susan; Palacios, Antonio; de Escobar, Anna Leese; In, Visarath

    2011-04-01

    In this work we numerical model series and parallel non-uniform superconducting quantum interference device (SQUID) array. Previous work has shown that series SQUID array constructed with a random distribution of loop sizes, (i.e. different areas for each SQUID loop) there exists a unique `anti-peak' at the zero magnetic field for the voltage versus applied magnetic field (V-B). Similar results extend to a parallel SQUID array where the difference lies in the arrangement of the Josephson junctions. Other system parameter such as bias current, the number of loops, and mutual inductances are varied to demonstrate the change in dynamic range and linearity of the V-B response. Application of the SQUID array as a low noise amplifier (LNA) would increase link margins and affect the entire communication system. For unmanned aerial vehicles (UAVs), size, weight and power are limited, the SQUID array would allow use of practical `electrically small' antennas that provide acceptable gain.

  8. Scanning SQUID microscopy with single electron spin sensitivity

    NASA Astrophysics Data System (ADS)

    Vasyukov, Denis

    2014-03-01

    Superconducting interference devices (SQUIDs) have been traditionally used for studying fundamental properties of magnetic materials and superconductors. Although widely used in scanning magnetic microscopy, their progress towards detection of small magnetic moments was stagnating of late due to limitations imposed by conventional designs of planar SQUIDs and contemporary lithography techniques, restricting sample-to-sensor distance smaller than ~ 0.5 micron and SQUIDs diameters smaller than ~ 200 nm. These limitations were overcome by the invention of a SQUID-on-tip device, subsequent realization of a SQUID-on-tip microscope, and by creation of an ultra-small sensor with spatial resolution of 20 nm and sensitivity to a single electron spin per 1 Hz bandwidth. In this talk I will describe the principles of scanning SQUID magnetometry, its applications to study superconductors and its potential for magnetic nano-scale imaging of novel materials.

  9. Coupled Serial and Parallel Non-uniform SQUIDs

    SciTech Connect

    Longhini, Patrick; In, Visarath; Berggren, Susan; Palacios, Antonio; Leese de Escobar, Anna

    2011-04-19

    In this work we numerical model series and parallel non-uniform superconducting quantum interference device (SQUID) array. Previous work has shown that series SQUID array constructed with a random distribution of loop sizes, (i.e. different areas for each SQUID loop) there exists a unique 'anti-peak' at the zero magnetic field for the voltage versus applied magnetic field (V-B). Similar results extend to a parallel SQUID array where the difference lies in the arrangement of the Josephson junctions. Other system parameter such as bias current, the number of loops, and mutual inductances are varied to demonstrate the change in dynamic range and linearity of the V-B response. Application of the SQUID array as a low noise amplifier (LNA) would increase link margins and affect the entire communication system. For unmanned aerial vehicles (UAVs), size, weight and power are limited, the SQUID array would allow use of practical 'electrically small' antennas that provide acceptable gain.

  10. A method for simulating a flux-locked DC SQUID

    NASA Technical Reports Server (NTRS)

    Gutt, G. M.; Kasdin, N. J.; Condron, M. R., II; Muhlfelder, B.; Lockhart, J. M.; Cromar, M. W.

    1993-01-01

    The authors describe a computationally efficient and accurate method for simulating a dc SQUID's V-Phi (voltage-flux) and I-V characteristics which has proven valuable in evaluating and improving various SQUID readout methods. The simulation of the SQUID is based on fitting of previously acquired data from either a real or a modeled device using the Fourier transform of the V-Phi curve. This method does not predict SQUID behavior, but rather is a way of replicating a known behavior efficiently with portability into various simulation programs such as SPICE. The authors discuss the methods used to simulate the SQUID and the flux-locking control electronics, and present specific examples of this approach. Results include an estimate of the slew rate and linearity of a simple flux-locked loop using a characterized dc SQUID.

  11. Digital filter design approach for SQUID gradiometers

    SciTech Connect

    Bruno, A.C.; Ribeiro, P.C.

    1988-04-15

    A review of the traditional method for designing gradiometers is made. A nonrecursive digital filter model for the gradiometer is presented, giving a new set of parameters for the gradiometer identification. Some designs are analyzed using the proposed set. As an example, a true differentiator is designed to be used as the SQUID input coil. It is shown that the differentiator has the same noise rejection as the conventional gradiometer but provides more signal sensitivity.

  12. Odorant Responsiveness of Squid Olfactory Receptor Neurons

    PubMed Central

    Mobley, Arie Sitthichai; Michel, William C.; Lucero, Mary T.

    2008-01-01

    In the olfactory organ of the squid, Lolliguncula brevis there are five morphological types of olfactory receptor neurons (ORNs). Previous work to characterize odor sensitivity of squid ORNs was performed on only two of the five types in dissociated primary cell cultures. Here we sought to establish the odorant responsiveness of all five types. We exposed live squid or intact olfactory organs to excitatory odors plus the activity marker, agmatine (AGB), an arginine derivative that enters cells through non-selective cation channels. An antibody against AGB was used to identify odorant-activated neurons. We were able to determine the ORN types of AGB-labeled cells based on their location in the epithelium, morphology and immunolabeling by a set of metabolites: arginine, aspartate, glutamate, glycine and glutathione. Of 389 neurons identified from metabolite-labeled tissue, 3% were type 1, 32% type 2, 33% type 3, 15% type 4 and 17% type 5. Each ORN type had different odorant specificity with type 3 cells showing the highest percentages of odorant-stimulated AGB labeling. Type 1 cells were rare and none of the identified type 1 cells responded to the tested odorants, which included glutamate, alanine and AGB. Glutamate is a behaviorally attractive odorant and elicited AGB labeling in types 2 and 3. Glutamate-activated AGB labeling was significantly reduced in the presence of the adenylate cyclase inhibitor, SQ22536 (80 ?M). These data suggest that the five ORN types differ in their relative abundance and odor responsiveness and that the adenylate cyclase pathway is involved in squid olfactory transduction. PMID:18484602

  13. Ceramic HTSC SQUID-based galvanometer

    SciTech Connect

    Uchaikin, S.V.; Hiep, L.H. )

    1992-06-01

    A highly sensitive galvanometer operating at liquid-nitrogen temperature for direct and low-frequency current measurements was developed on the basis of a HTSC SQUID. The direct-current sensitivity of the galvanometer is approximately 0.5 nA at an internal resistance of about 20 ohms. Its energy resolution in the white noise region is 2 x 10 exp 21 J/Hz. 11 refs.

  14. Dynamics of a spinor atom-SQUID

    NASA Astrophysics Data System (ADS)

    Mathew, Ranchu; Tiesinga, Eite

    2015-05-01

    Over the past few years, there has been a concerted effort at NIST studying the atomic analogue of a superconducting quantum interference device (SQUID). The atom-SQUID consists of a Bose-Einstein condensate in a ring trap with a rotating external weak link. The phenomena of persistent current and hysteresis have been experimentally observed in this system. We investigate the effect of the spin degree of freedom on the stability of persistent-current states and hysteresis in a spin-1 atom-SQUID. Inter-atomic interactions now allow coherent oscillations between the spin projections while conserving total magnetisation. We study the mean-field states of a spin-1 system within a two-mode approximation, where the two spatial modes are plane-wave modes with winding number zero and one. Furthermore, we calculate the Bogoliubov spectrum to study the combined effect of an external magnetic field and rotation rate on the stability and coupling of the spin and mass current.

  15. Compartment-Specific Phosphorylation of Squid Neurofilaments.

    PubMed

    Grant, Philip; Pant, Harish C

    2016-01-01

    Studies of the giant axon and synapse of third-order neurons in the squid stellate ganglion have provided a vast literature on neuronal physiology and axon transport. Large neuronal size also lends itself to comparative biochemical studies of cell body versus axon. These have focused on the regulation of synthesis, assembly, posttranslational modification and function of neuronal cytoskeletal proteins (microtubules (MTs) and neurofilaments (NFs)), the predominant proteins in axoplasm. These contribute to axonal organization, stability, transport, and impulse transmission responsible for rapid contractions of mantle muscles underlying jet propulsion. Studies of vertebrate NFs have established an extensive literature on NF structure, organization, and function; studies of squid NFs, however, have made it possible to compare compartment-specific regulation of NF synthesis, assembly, and function in soma versus axoplasm. Since NFs contain over 100 eligible sites for phosphorylation by protein kinases, the compartment-specific patterns of phosphorylation have been a primary focus of biochemical studies. We have learned that NF phosphorylation is tightly compartmentalized; extensive phosphorylation occurs only in the axonal compartment in squid and in vertebrate neurons. This extensive phosphorylation plays a key role in organizing NFs, in association with microtubules (MTs), into a stable, dynamic functional lattice that supports axon growth, diameter, impulse transmission, and synaptic activity. To understand how cytoskeletal phosphorylation is topographically regulated, the kinases and phosphatases, bound to NFs isolated from cell bodies and axoplasm, have also been studied. PMID:26795486

  16. Laying the groundwork for NEON's continental-scale ecological research

    NASA Astrophysics Data System (ADS)

    Dethloff, G.; Denslow, M.

    2013-12-01

    The National Ecological Observatory Network (NEON) is designed to examine a suite of ecological issues. Field-collected data from 96 terrestrial and aquatic sites across the U.S. will be combined with remotely sensed data and existing continental-scale data sets. Field collections will include a range of physical and biological types, including soil, sediment, surface water, groundwater, precipitation, plants, animals, insects, and microbes as well as biological sub-samples such as leaf material, blood and tissue samples, and DNA extracts. Initial data analyses and identifications of approximately 175,000 samples per year will occur at numerous external laboratories when all sites are fully staffed in 2017. Additionally, NEON will archive biotic and abiotic specimens at collections facilities where they will be curated and available for additional analyses by the scientific community. The number of archived specimens is currently estimated to exceed 130,000 per year by 2017. We will detail how NEON is addressing the complexities and challenges around this set of analyses and specimens and how the resulting high-quality data can impact ecological understanding. The raw data returned from external laboratories that is quality checked and served by NEON will be the foundation for many NEON data products. For example, sequence-quality nucleic acids extracted from surface waters, benthic biofilms, and soil samples will be building blocks for data products on microbial diversity. The raw sequence data will also be available for uses such as evolutionary investigations, and the extracts will be archived so others can acquire them for additional research. Currently, NEON is establishing contracts for the analysis and archiving of field-collected samples through 2017. During this period, NEON will gather information on the progress and success of this large-scale effort in order to determine the most effective course to pursue with external facilities. Two areas that NEON already knows to evaluate are the need for geographic expertise in taxonomic identifications and the capacity necessary to handle the volume of samples. NEON is also addressing challenges associated with external entities and the logistics of sample movement, data formatting, data ingestion, and reporting. For example, NEON is considering tools, such as web APIs, which could allow efficient transfer of data from external facilities. Having a standard format in place for that data will be critical to transfer success and quality assessment. NEON is also working on the implementation of quality control measures for diverse analytical and taxonomic processes across laboratories, and is developing an external audit process. Additionally, given NEON's open access approach, the Network is focused on selecting a sample identification protocol that aids in tracking samples with more involved analytical needs and also allows maximum utility for the scientific community. Given the complex nature and breadth of the project, NEON will be developing novel sample management systems as well as metadata schemas. These efforts insure integrity and quality from field to external facility to archive for each sample taken, providing high-quality data now and confidence in future research stemming from raw data generated by NEON and its collection specimens.

  17. Single SQUID frequency-domain multiplexer for large bolometer arrays

    SciTech Connect

    Yoon, Jongsoo; Clarke, John; Gildemeister, J.M.; Lee, Adrian T.; Myers, M.J.; Skidmore, J.T.; Richards, P.L.; Spieler, H.G.

    2001-08-20

    We describe the development of a frequency-domain superconducting quantum interference device (SQUID) multiplexer which monitors a row of low-temperature sensors simultaneously with a single SQUID. Each sensor is ac biased with a unique frequency and all the sensor currents are added in a superconducting summing loop. A single SQUID measures the current in the summing loop, and the individual signals are lock-in detected after the room temperature SQUID electronics. The current in the summing loop is nulled by feedback to eliminate direct crosstalk. We have built an eight-channel prototype and demonstrated channel separation and signal recovery.

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

    PubMed Central

    2013-01-01

    Background 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. Results 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. Conclusions 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. PMID:23418818

  19. A nanoscale SQUID operating at high magnetic fields

    SciTech Connect

    Lam, Simon K. H.; Clem, John R.; Yang, Wenrong

    2011-10-13

    A washer-free Nb nanoSQUID has been developed for measuring magnetization changes from nanoscale objects. The SQUID loop is etched into a 250 nm wide Au/Nb bilayer track and the diameter of the SQUID hole is {approx} 70 nm. In the presence of a magnetic field perpendicular to the plane of the SQUID, vortex penetration into the 250 nm wide track can be observed via the critical current-applied field characteristic and the value at which vortex first penetrates is consistent with the theoretical prediction. Upon removing the applied field, the penetrated vortices escape the track and the critical current at zero field is restored.

  20. A nanoscale SQUID operating at high magnetic fields

    SciTech Connect

    Lam, Simon K. H.; Clem, John R.; Yang, Wenrong

    2011-10-13

    A washer-free Nb nanoSQUID has been developed for measuring magnetization changes from nanoscale objects. The SQUID loop is etched into a 250 nm wide Au/Nb bilayer track and the diameter of the SQUID hole is ~ 70 nm. In the presence of a magnetic field perpendicular to the plane of the SQUID, vortex penetration into the 250 nm wide track can be observed via the critical current–applied field characteristic and the value at which vortex first penetrates is consistent with the theoretical prediction. Upon removing the applied field, the penetrated vortices escape the track and the critical current at zero field is restored.

  1. Low field SQUID MRI devices, components and methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H (Inventor); Hahn, Inseob (Inventor)

    2010-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  2. Low Field Squid MRI Devices, Components and Methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2014-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  3. Low field SQUID MRI devices, components and methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2011-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  4. Low Field Squid MRI Devices, Components and Methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2013-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  5. Electron Impact Excitation and Ionization of Neon

    NASA Astrophysics Data System (ADS)

    Zatsarinny, Oleg; Bartschat, Klaus

    2012-10-01

    We have further developed the B-Spline R-matrix (BSR) code [1] to allow for a large number of pseudo-states in the close-coupling expansion. In the present work, the BSRMPS approach [2] was employed to perform semi-relativistic (Breit-Pauli) close-coupling calculations for elastic scattering, excitation, and ionization of neon from both the ground state and the metastable excited states. Coupling to the ionization continuum through the pseudo-states is important for low-energy elastic scattering (to represent polarizability effects), for excitation in the ``intermediate'' energy regime of about 1-5 times the ionization potential, and to allow for the calculation of ionization processes by transforming the results obtained for excitation of the positive-energy pseudo-states. The current results represent a significant extension of our earlier near-threshold work [3] and previous non-relativistic RMPS calculations [4,5].[4pt] [1] O. Zatsarinny, Comp. Phys. Commun. 174 (2006) 273.[0pt] [2] O. Zatsarinny and K. Bartschat, Phys. Rev. Lett. 107 (2011) 023203.[0pt] [3] O. Zatsarinny and K. Bartschat, J. Phys. B 37 (2004) 2173.[0pt] [4] C. P. Ballance and D. C. Griffin, J. Phys. B 37 (2004) 2943.[0pt] [5] C. P. Ballance et al., J. Phys. B 37 (2004) 4779.

  6. Multistage Zeeman deceleration of metastable neon

    SciTech Connect

    Wiederkehr, Alex W.; Motsch, Michael; Hogan, Stephen D.; Andrist, Markus; Schmutz, Hansjuerg; Lambillotte, Bruno; Agner, Josef A.; Merkt, Frederic

    2011-12-07

    A supersonic beam of metastable neon atoms has been decelerated by exploiting the interaction between the magnetic moment of the atoms and time-dependent inhomogeneous magnetic fields in a multistage Zeeman decelerator. Using 91 deceleration solenoids, the atoms were decelerated from an initial velocity of 580 m/s to final velocities as low as 105 m/s, corresponding to a removal of more than 95% of their initial kinetic energy. The phase-space distribution of the cold, decelerated atoms was characterized by time-of-flight and imaging measurements, from which a temperature of 10 mK was obtained in the moving frame of the decelerated sample. In combination with particle-trajectory simulations, these measurements allowed the phase-space acceptance of the decelerator to be quantified. The degree of isotope separation that can be achieved by multistage Zeeman deceleration was also studied by performing experiments with pulse sequences generated for {sup 20}Ne and {sup 22}Ne.

  7. Neon color spreading in dynamic displays: temporal factors.

    PubMed

    Cicchini, Marco; Spillmann, Lothar

    2013-01-01

    When a red star is placed in the middle of an Ehrenstein figure so as to be collinear with the surrounding black rays, a reddish veil is perceived to fill the white center. This is called neon color spreading. To better understand the processes that give rise to this phenomenon, we studied the temporal properties of the effect. Specifically, we presented a "sustained" black Ehrenstein figure (rays) for 600 ms and a "transient" red star for 48 ms, or the converse pattern, at various stimulus onset asynchronies (-100-700 ms) and asked subjects to compare the strength of the neon color in the test stimulus to that of a reference pattern in which the transient star had an onset asynchrony of 300 ms. Additional exposure durations of 24 and 96 ms were used for each transient stimulus in order to study the effect of temporal integration. Simultaneity of the on- and off-transients of the star and the Ehrenstein rays were found to optimize neon color spreading, especially when both stimuli terminated together. Longer exposure durations of the transient stimulus up to 96 ms further improved the effect. Neon color spreading was much reduced when the transient stimulus was presented soon after the beginning of the sustained stimulus, with a gradual build-up towards the end. These results emphasize the importance of stimulus onset asynchrony (SOA) and stimulus termination asynchrony (STA) for the perception of neon color spreading. PMID:24097045

  8. Development of airborne remote sensing instrumentations for NEON

    NASA Astrophysics Data System (ADS)

    Johnson, Brian R.; Kampe, Thomas U.; Kuester, Michele

    2010-08-01

    Airborne remote sensing plays a critical role in the scaling strategy underpinning the National Ecological Observatory Network (NEON) design. Airborne spectroscopy and waveform LiDAR will quantify plant species type and function, and vegetation structure and heterogeneity at the scale of individual shrubs and larger plants (1-3 meters) over hundreds of square kilometers. Panchromatic photography at better than 30 cm resolution will retrieve fine-scale information regarding land use, roads, impervious surfaces, and built structures. NEON will build three airborne systems to allow for routine coverage of NEON sites (60 sites nationally) and the capacity to respond to investigator requests for specific projects. The system design achieves a balance between performance, and development cost and risk. The approach takes full advantage of existing commercial airborne LiDAR and camera components. However, requirements for the spectrometer represent a significant advancement in technology. A pushbroom imaging spectrometer design is being proposed to simultaneously achieve high spatial, spectral and signal-to-noise ratio and a high degree of uniformity in response across wavelength and a wide field of view. To reduce risk during NEON construction, a spectrometer design verification unit is under development by the Jet Propulsion Laboratory to demonstrate that the design and component technologies meet operational and performance requirements. This paper presents an overview of system design, key requirements and development status of the NEON airborne instrumentation.

  9. Read-out electronics for DC squid magnetic measurements

    DOEpatents

    Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Independence, MO)

    2002-01-01

    Read-out electronics for DC SQUID sensor systems, the read-out electronics incorporating low Johnson noise radio-frequency flux-locked loop circuitry and digital signal processing algorithms in order to improve upon the prior art by a factor of at least ten, thereby alleviating problems caused by magnetic interference when operating DC SQUID sensor systems in magnetically unshielded environments.

  10. SQUID magnetometry from nanometer to centimeter length scales

    SciTech Connect

    Hatridge, Michael J.

    2010-06-28

    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. NEON INSIGHTS FROM OLD SOLAR X-RAYS: A PLASMA TEMPERATURE DEPENDENCE OF THE CORONAL NEON CONTENT

    SciTech Connect

    Drake, Jeremy J.

    2011-12-10

    An analysis using modern atomic data of fluxes culled from the literature for O VIII and Ne IX lines observed in solar active regions by the P78 and Solar Maximum Mission satellites confirms that the coronal Ne/O abundance ratio varies by a factor of two or more, and finds an increase in Ne/O with increasing active region plasma temperature. The latter is reminiscent of evidence for increasing Ne/O with stellar activity in low-activity coronae that reaches a 'neon saturation' in moderately active stars at approximately twice the historically accepted solar value of about 0.15 by number. We argue that neon saturation represents the underlying stellar photospheric compositions, and that low-activity coronae, including that of the Sun, are generally depleted in neon. The implication would be that the solar Ne/O abundance ratio should be revised upward by a factor of about two to n(Ne)/n(O) {approx} 0.3. Diverse observations of neon in the local cosmos provide some support for such a revision. Neon would still be of some relevance for reconciling helioseismology with solar models computed using recently advocated chemical mixtures with lower metal content.

  12. Helium and neon isotopes in deep Pacific Ocean sediments

    NASA Technical Reports Server (NTRS)

    Nier, A. O.; Schlutter, D. J.; Brownlee, D. E.

    1990-01-01

    Helium and neon concentration measurements, along with isotope ratio determinations, have been made for particles collected in the deep Pacific with a magnetic sled, and they are believed to be of extraterrestrial origin. Analyses were made for samples consisting of composites of many extremely fine particles and for several individual particles large enough to contain sufficient gas for analysis but small enough to escape melting in their passage through the atmosphere. Step-heating was employed to extract the gas. Cosmic-ray spallation products or solar-wind helium and neon, if present, were not abundant enough to account for the isotopic compositions measured. In the case of the samples of magnetic fines, the low temperature extractions provided elemental and isotopic ratios in the general range found for the primordial gas in carbonaceous chondrites and gas-rich meteorites. The isotopic ratios found in the high temperature extractions suggest the presence of solar-flare helium and neon.

  13. Purification and Liquefacttion of Neon Using a Helium Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Boeck, S.

    2010-04-01

    The cryogenic plant developed by Linde Kryotechnik is used to extract neon out of a crude gas flow coming from an air separation plant. The crude gas is cooled down by a two stage helium refrigeration process using the Linde Kryotechnik dynamic gas bearing turbines. After the first cooling stage, nitrogen is liquefied and separated from the crude gas. The Cryogenic adsorbers located at a temperature level below 80 K clean the crude gas from remaining nitrogen traces before the neon-helium mixture enters the final cooling stage. In the second cooling stage neon is liquefied and separated from the helium. The final product quality will be achieved within a rectification column at low pressure level.

  14. Experimental study on neon refrigeration system using commercial helium compressor

    NASA Astrophysics Data System (ADS)

    Ko, Junseok; Kim, Hyobong; Hong, Yong-Ju; Yeom, Hankil; Koh, Deuk-Yong; Park, Seong-Je

    2012-06-01

    In this study, we developed neon refrigeration system using commercial helium compressor which was originally designed for GM cryocooler. We performed this research as precedent study before developing neon refrigeration system for small-scale hydrogen liquefaction system. The developed system is based on precooled Linde-Hampson system with liquid nitrogen as precoolant. Design parameters of heat exchangers are determined from thermodynamic cycle analysis with operating pressure of 2 MPa and 0.4 MPa. Heat exchangers have concentric-tube heat exchanger configuration and orifice is used as Joule- Thomson expansion device. In experiments, pressure, temperature, mass flow rate and compressor input power are measured as charging pressure. With experimental results, the characteristics of heat exchanger, Joule-Thomson expansion and refrigeration effect are discussed. The developed neon refrigeration system shows the lowest temperature of 43.9 K.

  15. SQUID detection of magnetically-tagged microorganisms

    NASA Astrophysics Data System (ADS)

    Grossman, Helene L.

    2001-03-01

    A fast and versatile technique has been developed for detecting small quantities of specific microorganisms or molecules. The target analytes are bound to a substrate and placed in the measurement cell of a ``microscope'' based on a high-transition temperature Superconducting QUantum Interference Device (SQUID). A solution containing nanometer-size magnetite particles, coated with antibodies specific to the target, is added. The particles, which bind to the target via the antibody-antigen interaction, are superparamagnetic with a Nel relaxation time of ~ 1 s. A pulsed magnetic field aligns the dipole moments, and the SQUID measures the magnetic relaxation signal when the field is turned off. Unbound magnetic particles relax rapidly ( ~ 15 ?s) by Brownian rotation and are not detected. On the other hand, particles bound to targets cannot rotate and instead relax slowly by the Nel mechanism. As a result, only bound particles contribute to the signal, allowing for quantification of the number of targets present without the need for a wash step. The current system can reproducibly detect as few as 510^4 magnetic particles - a sensitivity greater than that of the commonly used Enzyme-Linked Immunosorbent Assay (ELISA). A new SQUID microscope has been designed and built, which may improve the sensitivity by up to two orders of magnitude. This technique could be used to detect a wide range of bacteria, viruses, and molecules, with potential applications in the food industry, clinical settings, or research laboratories. Supported by U.S. DOE Contract DE-AC03-76SF00098

  16. Capacitively-Coupled SQUID Bias for Time Division Multiplexing

    NASA Astrophysics Data System (ADS)

    Prle, D.; Voisin, F.; Piat, M.; Martino, J.; Decourcelle, T.; Chapron, C.

    2014-08-01

    The multiplexing scheme presented in this paper is part of the readout chain of the QUBIC instrument devoted to cosmic microwave background polarization observations. It is based on time domain multiplexing using superconducting quantum interference devices (SQUIDs) to read out a large array of superconducting bolometers. The originality of the multiplexer presented here lies in the use of capacitors for the SQUID addressing. Capacitive coupling allows us to bias many SQUIDs in parallel (in a 2D topology), with low crosstalk and low power dissipation of the cryogenic front-end readout. However, capacitors in series with the SQUID require a modification of the addressing strategy. This paper presents a bias reversal technique adopted to sequentially address the SQUIDs through capacitors using a cryogenic SiGe integrated circuit. We further present the different limitations of this technique and how to choose the proper capacitance for a given multiplexing frequency and current source compliance.

  17. A SQUID gradiometer module with large junction shunt resistors

    NASA Astrophysics Data System (ADS)

    Qiu, Yang; Liu, Chao; Zhang, Shu-Lin; Zhang, Guo-Feng; Wang, Yong-Liang; Li, Hua; Zeng, Jia; Kong, Xiang-Yan; Xie, Xiao-Ming

    2014-08-01

    A dual-washer superconducting quantum interference device (SQUID) with a loop inductance of 350 pH and two on-washer integrated input coils is designed according to conventional niobium technology. In order to obtain a large SQUID flux-to-voltage transfer coefficient, the junction shunt resistance is selected to be 33 ?. A vertical SQUID gradiometer module with a baseline of 100 mm is constructed by utilizing such a SQUID and a first-order niobium wire-wound antenna. The sensitivity of this module reaches about 0.2 fT/(cmHz1/2) in the white noise range using a direct readout scheme, i.e., the SQUID is directly connected to an operational amplifier, in a magnetically shielded room. Some magnetocardiography (MCG) measurements with a sufficiently high signal-to-noise ratio (SNR) are demonstrated.

  18. Current - Flux characteristics of a hysteretic asymmetric dc SQUID qubit

    NASA Astrophysics Data System (ADS)

    Paik, Hanhee

    2005-03-01

    We present data and simulations of the behavior of a superconducting qubit, the asymmetric hysteretic dc SQUID or inductively isolated Josephson jucntion. Measurements of the current-flux (I-?) characteristics were taken on an Al/AlOx/Al dc SQUID at 100 mK and compared to analytical and numerical simulations. The SQUID has one junction with twice the critical current of the other junction, and one arm of a relatively large inductance, compared to the other arm of the SQUID. With this configuration, which was first proposed by Martinis et al.[1], the larger junction acts as an inductively isolated qubit, while the smaller junction acts as a detector. From the I-? curve, we extract the SQUID parameters and reveals how well isolated the qubit is from its leads. This work is supported by the Department of Defense, NSF and the Center for Superconductivity Research. [1] Martinis et al. Phys. Rev Lett. 89 117901 (2002)

  19. Planar thin film SQUID with integral flux concentrator

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N. (Inventor); Sisk, Robert C. (Inventor)

    1988-01-01

    A thin film SQUID is disclosed having improved flux concentration combined with simplicity of design and fabrication. The SQUID starts with a wafer like substrate having simple planar geometry. A large area of superconducting film is coated on the substrate, with a small open or uncoated area remaining at its center to define a SQUID loop, and a gap in the film formed, beginning at the outer circumferential edge of the substrate and extending radially inward to the open area. A Josephson junction is formed across the gap near the open area to interrupt the electrical continuity of the SQUID loop. A coil is attached to the surface of the substrate, electrically insulated from the superconducting film, and is energized to induce flux within the SQUID which is concentrated within the open area.

  20. Fast imaging of intact and shattered cryogenic neon pellets

    SciTech Connect

    Wang, Zhehui; Combs, S. K.; Baylor, L. R.; Foust, C. R.; Lyttle, M. S.; Meitner, S. J.; Rasmussen, D. A.

    2014-11-15

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100-µm- and sub-µs-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of µm to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  1. Fast imaging of intact and shattered cryogenic neon pellets.

    PubMed

    Wang, Zhehui; Combs, S K; Baylor, L R; Foust, C R; Lyttle, M S; Meitner, S J; Rasmussen, D A

    2014-11-01

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100-m- and sub-s-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of m to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development. PMID:25430370

  2. Fast Imaging of Intact and Shattered Cryogenic Neon Pellets

    SciTech Connect

    Wang, Zhehui; Combs, Stephen Kirk; Baylor, Larry R; Foust, Charles R; Lyttle, Mark S; Meitner, Steven J; Rasmussen, David A

    2014-01-01

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100- m- and sub- s-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of m to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  3. Peaked density profiles due to neon injection on FTU

    NASA Astrophysics Data System (ADS)

    Mazzotta, C.; Ban Navarro, A.; Gabellieri, L.; Marinucci, M.; Pucella, G.; Told, D.; Tudisco, O.; Apruzzese, G.; Artaserse, G.; Sozzi, C.; the FTU Team

    2015-07-01

    Neon injection in FTU can cause a spontaneous increase of the line-average density by a factor 2. The recent experiments were devoted to characterize the plasma response to the neon injection at different densities and plasma currents. A qualitative estimate from UV spectroscopy measurements indicates that the density behaviour cannot be attributed simply to the stripped electrons from the puffed impurity, but a modification of particle transport should be invoked in order to explain the spontaneous rise and the higher peaking. JETTO transport and GENE gyrokinetic codes analyses, as well as a calculation of the electron diffusion coefficients D and pinch velocity U, contribute to feature the peaking effect.

  4. Boiling incipience and convective boiling of neon and nitrogen

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1977-01-01

    Forced convection and subcooled boiling heat transfer data for liquid nitrogen and liquid neon were obtained in support of a design study for a 30 tesla cryomagnet cooled by forced convection of liquid neon. The cryogen data obtained over a range of system pressures, fluid flow rates, and applied heat fluxes were used to develop correlations for predicting boiling incipience and convective boiling heat transfer coefficients in uniformly heated flow channels. The accuracy of the correlating equations was then evaluated. A technique was also developed to calculate the position of boiling incipience in a uniformly heated flow channel. Comparisons made with the experimental data showed a prediction accuracy of + or - 15 percent.

  5. Fast imaging of intact and shattered cryogenic neon pellets

    NASA Astrophysics Data System (ADS)

    Wang, Zhehui; Combs, S. K.; Baylor, L. R.; Foust, C. R.; Lyttle, M. S.; Meitner, S. J.; Rasmussen, D. A.

    2014-11-01

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100-m- and sub-s-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of m to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  6. Cross-linking chemistry of squid beak.

    PubMed

    Miserez, Ali; Rubin, Daniel; Waite, J Herbert

    2010-12-01

    In stark contrast to most aggressive predators, Dosidicus gigas (jumbo squids) do not use minerals in their powerful mouthparts known as beaks. Their beaks instead consist of a highly sclerotized chitinous composite with incremental hydration from the tip to the base. We previously reported l-3,4-dihydroxyphenylalanine (dopa)-histidine (dopa-His) as an important covalent cross-link providing mechanical strengthening to the beak material. Here, we present a more complete characterization of the sclerotization chemistry and describe additional cross-links from D. gigas beak. All cross-links presented in this report share common building blocks, a family of di-, tri-, and tetra-histidine-catecholic adducts, that were separated by affinity chromatography and high performance liquid chromatography (HPLC) and identified by tandem mass spectroscopy and proton nuclear magnetic resonance ((1)H NMR). The data provide additional insights into the unusually high cross-link density found in mature beaks. Furthermore, we propose both a low molecular weight catechol, and peptidyl-dopa, to be sclerotization agents of squid beak. This appears to represent a new strategy for forming hard tissue in animals. The interplay between covalent cross-linking and dehydration on the graded properties of the beaks is discussed. PMID:20870720

  7. Crystallization and crystal properties of squid rhodopsin

    SciTech Connect

    Murakami, Midori; Kitahara, Rei; Gotoh, Toshiaki; Kouyama, Tsutomu

    2007-06-01

    Truncated rhodopsin from the retina of the squid Todarodes pacificus was extracted and crystallized by the sitting-drop vapour-diffusion method. Hexagonal crystals grown in the presence of octylglucoside and ammonium sulfate diffracted to 2.8 resolution. Rhodopsin, a photoreceptor membrane protein in the retina, is a prototypical member of the G-protein-coupled receptor family. In this study, rhodopsin from the retina of the squid Todarodes pacificus was treated with V8 protease to remove the C-terminal extension. Truncated rhodopsin was selectively extracted from the microvillar membranes using alkyl glucoside in the presence of zinc ions and was then crystallized by the sitting-drop vapour-diffusion method. Of the various crystals obtained, hexagonal crystals grown in the presence of octylglucoside and ammonium sulfate diffracted to 2.8 resolution. The diffraction data suggested that the crystal belongs to space group P6{sub 2}, with unit-cell parameters a = b = 122.1, c = 158.6 . Preliminary crystallographic analysis, together with linear dichroism results, suggested that the rhodopsin dimers are packed in such a manner that their transmembrane helices are aligned nearly parallel to the c axis.

  8. Broadband Tunable Transparency in rf SQUID Metamaterial

    NASA Astrophysics Data System (ADS)

    Zhang, Daimeng; Trepanier, Melissa; Mukhanov, Oleg; Jung, Philipp; Butz, Susanne; Ustinov, Alexey; Anlage, Steven

    2015-03-01

    We demonstrate a metamaterial with broadband tunable transparency in microwave electromagnetic fields. This metamaterial is made of Radio Frequency Superconducting QUantum Interference Devices (rf SQUIDs). We show both experimentally and theoretically that the resonance of this metamaterial totally disappears when illuminated with electromagnetic waves of certain power ranges, so that waves can propagate through the metamaterial with little dissipation in a wide frequency spectrum. Unlike traditional electromagnetically induced transparency, high transmission through this metamaterial is due to the intrinsic nonlinearity of the rf SQUID. Transparency occurs when the metamaterial enters its bistability regime. We can control the metamaterial to be transparent or opaque by switching between the two states depending on the initial conditions and signal scanning directions. We also show that the degree of transparency can be tuned by temperature, power of the incident wave, and dc magnetic field and discuss analytical and numerical models that reveal how to systematically control the transparency regime. The metamaterial has potential application in fast tunable digital filter, power limiter and auto-cloaking. This work is supported by the NSF-GOALI and OISE programs through grant # ECCS-1158644, and CNAM.

  9. The curvy photonics of squid camouflage

    NASA Astrophysics Data System (ADS)

    Sweeney, Alison; Holt, Amanda; Daniel, Morse; Stramski, Dariusz

    2013-03-01

    Cephalopods (squids and octopuses) ubiquitously possess reflective structures in their skin composed of ``reflectin'' proteins. Although a few simple laminar, Bragg-stack type optical structures have been known in a handful of common squid species for some time, our extensive survey of optically active tissues of exotic deep-sea species has revealed complex, extended curvatures and topologies in dermal reflectors of these rarely-studied animals. Molecular deep-sequencing has revealed these structures also to be composed of reflectin-like proteins. Here we show a survey of some of these deep-sea reflector structures, and present evidence that each novel structure may be a transform of the radiance in the optical niche in the ocean where each of these species live, such that light reflecting off the sides of these animals in their specific ocean habitat resembles the light that would be transmitted through the animals if they were transparent, from many different viewing angles and possible ocean depths.

  10. Ribosomes in the squid giant axon.

    PubMed

    Bleher, R; Martin, R

    2001-01-01

    Ribosome clusters, referred to as endoaxoplasmic plaques, were documented and quantitatively analyzed in the squid giant axon at the light and electron microscopic levels. The methods included nonspecific high affinity fluorescence staining of RNA by YOYO-1, specific immunofluorescence labeling of ribosomal RNA, electron energy loss spectroscopic mapping of ribosomal phosphorus, and conventional transmission electron microscopy. The endoaxoplasmic plaques were sharply defined, oval in shape, and less than 2 microm in diameter. While they were very numerous in the postsynaptic axonal area of the giant synapse, the frequency of occurrence was much lower in the peripheral giant axon, with a density of about 1 plaque/1000 microm3. Their distribution was random within axoplasm, with no preferential localization near the membrane. The several thousand ribosomes in a plaque usually were not membrane bound, but vesicular structures were observed in or near plaques; plaques were often surrounded by mitochondria. We conclude that ribosomes, a requisite machinery for protein synthesis, are present in the squid giant axon in discrete configurations. PMID:11719007

  11. Cross-linking Chemistry of Squid Beak*

    PubMed Central

    Miserez, Ali; Rubin, Daniel; Waite, J. Herbert

    2010-01-01

    In stark contrast to most aggressive predators, Dosidicus gigas (jumbo squids) do not use minerals in their powerful mouthparts known as beaks. Their beaks instead consist of a highly sclerotized chitinous composite with incremental hydration from the tip to the base. We previously reported l-3,4-dihydroxyphenylalanine (dopa)-histidine (dopa-His) as an important covalent cross-link providing mechanical strengthening to the beak material. Here, we present a more complete characterization of the sclerotization chemistry and describe additional cross-links from D. gigas beak. All cross-links presented in this report share common building blocks, a family of di-, tri-, and tetra-histidine-catecholic adducts, that were separated by affinity chromatography and high performance liquid chromatography (HPLC) and identified by tandem mass spectroscopy and proton nuclear magnetic resonance (1H NMR). The data provide additional insights into the unusually high cross-link density found in mature beaks. Furthermore, we propose both a low molecular weight catechol, and peptidyl-dopa, to be sclerotization agents of squid beak. This appears to represent a new strategy for forming hard tissue in animals. The interplay between covalent cross-linking and dehydration on the graded properties of the beaks is discussed. PMID:20870720

  12. Base distance optimization for SQUID gradiometers

    SciTech Connect

    Garachtchenko, A.; Matlashov, A.; Kraus, R.

    1998-12-31

    The measurement of magnetic fields generated by weak nearby biomagnetic sources is affected by ambient noise generated by distant sources both internal and external to the subject under study. External ambient noise results from sources with numerous origins, many of which are unpredictable in nature. Internal noise sources are biomagnetic in nature and result from muscle activity (such as the heart, eye blinks, respiration, etc.), pulsation associated with blood flow, surgical implants, etc. Any magnetic noise will interfere with measurements of magnetic sources of interest, such as magnetoencephalography (MEG), in various ways. One of the most effective methods of reducing the magnetic noise measured by the SQUID sensor is to use properly designed superconducting gradiometers. Here, the authors optimized the baseline length of SQUID-based symmetric axial gradiometers using computer simulation. The signal-to-noise ratio (SNR) was used as the optimization criteria. They found that in most cases the optimal baseline is not equal to the depth of the primary source, rather it has a more complex dependence on the gradiometer balance and the ambient magnetic noise. They studied both first and second order gradiometers in simulated shielded environments and only second order gradiometers in a simulated unshielded environment. The noise source was simulated as a distant dipolar source for the shielded cases. They present optimal gradiometer baseline lengths for the various simulated situations below.

  13. Enhancements to a Superconducting Quantum Interference Device (SQUID) Multiplexer Readout and Control System

    NASA Technical Reports Server (NTRS)

    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.

  14. Enhancements to a superconducting quantum interference device (SQUID) multiplexer readout and control system

    NASA Astrophysics Data System (ADS)

    Forgione, Joshua B.; Benford, Dominic J.; Buchanan, Ernest D.; Moseley, S. H., Jr.; Rebar, Joyce; Shafer, Richard A.

    2004-10-01

    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 III 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 III 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.

  15. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    ERIC Educational Resources Information Center

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature

  16. NEON Data Products: Enabling Continental-Scale Ecological Science

    NASA Astrophysics Data System (ADS)

    Berukoff, S. J.

    2011-12-01

    The National Ecological Observatory Network (NEON) is a NSF-funded major research and facilities initiative under development, designed to address how climate change, land use change, and invasive species affect ecological science on a continental scale. The standardization of measurement methodologies, engineering practice, and data organization across NEON's sixty sites fosters the creation of ecological data products. These data products are community-approved and Observatory-vetted, and cover the breadth of NEON collection activities, including measurements of physical variables such as air, water, and soil temperature and chemistry, observations and analyses of species and habitats, and airborne spectral and LiDAR remote sensing. Together, these low-level (fundamental measurement and observation data)and high-level (integrative, continental-scale assessments) will be useful for scientists, students, educators, policymakers, and the general public. Here, we discuss the development status of NEON's data product suites, describing how they are constructed and vetted, and provide an example of how one current effort will provide several foundational data products. Further, we discuss and solicit feedback for how stakeholder communities can contribute to their veracity and validation.

  17. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    ERIC Educational Resources Information Center

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature…

  18. Recent Results of a New Microwave SQUID Multiplexer

    NASA Technical Reports Server (NTRS)

    Hahn, Inseob; Limketkai, B.; Bumble, B.; LeDuc, H. G.

    2007-01-01

    We are developing a proof-of-concept microwave SQUID multiplexer containing four SQUIDs coupled to GHz frequency resonant circuits and fed with a single microwave readout line. The resonators are half-wave coplanar waveguide sections and are similar to the structures used for the microwave kinetic inductance detectors developed in our group. Optimal values for the interdigital gap capacitors were determined to maximize the sensitivity of the transmitted and reflected microwave signal with respect to changes in the dynamic resistance of the SQUID. The dc current-bias line for the SQUID has an in-line inductive high frequency filter to minimize coupling between the bias line and resonator. A high frequency modulation scheme is proposed to eliminate the need for individual flux biasing of the SQUIDs, which extends the dynamic range of the readout. In this scheme a common modulation signal is imposed on each SQUID and the received signal is demodulated at one and two times the modulation frequency to maintain sensitivity at any flux state. We present the recent results of the microwave SQUID multiplexer system operating at a readout frequency range of 10 - 11GHz.

  19. The NEON Aquatic Network: Expanding the Availability of Biogeochemical Data

    NASA Astrophysics Data System (ADS)

    Vance, J. M.; Bohall, C.; Fitzgerald, M.; Utz, R.; Parker, S. M.; Roehm, C. L.; Goodman, K. J.; McLaughlin, B.

    2013-12-01

    Aquatic ecosystems are facing unprecedented pressure from climate change and land-use practices. Invasive species, whether plant, animal, insect or microbe present additional threat to aquatic ecosystem services. There are significant scientific challenges to understanding how these forces will interact to affect aquatic ecosystems, as the flow of energy and materials in the environment is driven by multivariate and non-linear biogeochemical cycles. The National Ecological Observatory Network (NEON) will collect and provide observational data across multiple scales. Sites were selected to maximize representation of major North American ecosystems using a multivariate geographic clustering method that partitioned the continental US, AK, HI, and Puerto Rico into 20 eco-climatic domains. The NEON data collection systems and methods are designed to yield standardized, near real-time data subjected to rigorous quality controls prior to public dissemination through an online data portal. NEON will collect data for 30 years to facilitate spatial-temporal analysis of environmental responses and drivers of ecosystem change, ranging from local through continental scales. Here we present the NEON Aquatic Network, a multi-parameter network consisting of a combination of in situ sensor and observational data. This network will provide data to examine biogeochemical, biological, hydrologic and geomorphic metrics at 36 sites, which are a combination of small 1st/2nd order wadeable streams, large rivers and lakes. A typical NEON Aquatic site will host up to two in-stream sensor sets designed to collect near-continuous water quality data (e.g. pH/ORP, temperature, conductivity, dissolved oxygen, CDOM) along with up to 8 shallow groundwater monitoring wells (level, temp., cond.), and a local meteorological station (e.g. 2D wind speed, PAR, barometric pressure, temperature, net radiation). These coupled sensor suites will be complemented by observational data (e.g. water/sediment chemistry, aquatic organisms, geomorphology). The aquatic network will produce ~212 low-level data products for each site. NEON will produce several higher level data products such as measurements of whole-stream metabolism, gross primary productivity, ecosystem respiration, and fluxes of nitrogen, phosphorous and carbon that will enable users to analyze processes on a gross scale. These data may be integrated with NEON's terrestrial and airborne networks to bridge the gap between aquatic and terrestrial biogeochemical research. The NEON Aquatic Network is poised to greatly expand our ability to create more robust biogeochemical models. For example, hydrologic and stable isotope data will allow investigation of terrestrial-aquatic carbon flux. Constraints provided by NEON's terrestrial and atmospheric data concurrent with remotely sensed data will facilitate the scaling to regional and continental scales, potentially leading to greater accuracy in the global carbon budget. The NEON Aquatic Network represents a powerful tool that will give the scientific community access to standardized data over spatiotemporal scales that are needed to answer fundamental questions about natural ecological variability and responses to changes in the environment.

  20. HTS ion damage Josephson junction technology for SQUID arrays

    NASA Astrophysics Data System (ADS)

    Ouanani, S.; Kermorvant, J.; Crt, D.-G.; Lematre, Y.; Mage, J.-C.; Marcilhac, B.; Bergeal, N.; Malnou, M.; Lesueur, J.; Mailly, D.; Ulysse, C.

    2014-05-01

    The high temperature superconducting (HTS) Josephson Junction (JJ) ion damage technology we are developing is well suited for making large SQUID arrays. We have studied arrays of similar SQUIDs together with large SQIFs (Superconducting Quantum Interference Filter) with 2000 SQUIDs of different loop areas. Magnetic field sensitivity has been measured in both types of devices as a function of bias current and temperature. The effects of the barrier thickness (from 20 to 80 nm) and JJ length (2 or 5 ?m) on characteristics have been investigated.

  1. Squid as nutrient vectors linking Southwest Atlantic marine ecosystems

    NASA Astrophysics Data System (ADS)

    Arkhipkin, Alexander I.

    2013-10-01

    Long-term investigations of three abundant nektonic squid species from the Southwest Atlantic, Illex argentinus, Doryteuthis gahi and Onykia ingens, permitted to estimate important population parameters including individual growth rates, duration of ontogenetic phases and mortalities. Using production model, the productivity of squid populations at different phases of their life cycle was assessed and the amount of biomass they convey between marine ecosystems as a result of their ontogenetic migrations was quantified. It was found that squid are major nutrient vectors and play a key role as transient 'biological pumps' linking spatially distinct marine ecosystems. I. argentinus has the largest impact in all three ecosystems it encounters due to its high abundance and productivity. The variable nature of squid populations increases the vulnerability of these biological conveyers to overfishing and environmental change. Failure of these critical biological pathways may induce irreversible long-term consequences for biodiversity, resource abundance and spatial availability in the world ocean.

  2. Multiplexed Phase qubit readout using SQUID-resonators

    NASA Astrophysics Data System (ADS)

    Whittaker, Jed; Allman, Michael; Altomare, Fabio; Cicak, Katarina; Li, Dale; Park, Jae; Sirois, Adam; Strong, Joshua; Simmonds, Raymond

    2009-03-01

    Flux biased phase qubits have traditionally been read out using a critical current switching technique of a coupled DC SQUID. This method has three limitations: it is extremely slow (orders of magnitude longer than typical energy relaxation times), difficult to multiplex, and by exceeding the critical current, it is dissipative and feeds broadband radiation back into the qubit, decohering its state. We are developing a SQUID-resonator readout method that addresses all three of these limitations. By operating the SQUID as a resonator, we can measure the state of the qubit quickly (on the order of its coherence time), we can multiplex resonant readout lines, and we can operate on the SQUID's supercurrent branch eliminating dissipation and decohering radiation. This faster, quieter readout should allow us to use measured results for real-time quantum feedback.

  3. Nonstandard applications of superconducting quantum interferometers: SQUIDS (Review)

    SciTech Connect

    Odegnal, M.

    1985-01-01

    Some applications of superconducting quantum interferometers are studied. The problems of quantum noise in the Josephson junction are discussed, theoretical estimates of their magnitude are given, and ways for achieving the limiting sensitivity of SQUIDs are indicated. Applications of SQUIDs in checking some basic physical laws (Newton's law, the principle of equivalence of inertial and gravitational masses, general relativity), in elementary particle physics (search for quarks and magnetic monopoles), in geophysics (magnetotelluric measurements, gradiometric measurements, gravimetric experiments, etc.), and in ultra-low-temperature physics (nuclear gyroscope, SQUIDs and NMR, ultra-low-temperature thermometry) are described. Both past and future experiments are studied and some further applications of SQUID-based magnetometers are indicated.

  4. Weld quality evaluation using a high temperature SQUID array

    SciTech Connect

    Clark, D. D.; Espy, M. A.; Kraus, Robert H., Jr.; Matlachov, A. N.; Lamb, J. S.

    2002-01-01

    This paper presents preliminary data for evaluating weld quality using high temperature SQUIDS. The SQUIDS are integrated into an instrument known as the SQUID Array Microscope, or SAMi. The array consists of ll SQUIDs evenly distributed over an 8.25 mm baseline. Welds are detected using SAMi by using an on board coil to induce eddy currents in a conducting sample and measuring the resulting magnetic fields. The concept is that the induced magnetic fields will differ in parts of varying weld quality. The data presented here was collected from three stainless steel parts using SAMi. Each part was either solid, included a good weld, or included a bad weld. The induced magnetic field's magnitude and phase relative to the induction signal were measured. For each sample considered, both the magnitude and phase data were measurably different than the other two samples. These results indicate that it is possible to use SAMi to evaluate weld quality.

  5. Development of a colorimetric sensor array for squid spoilage assessment.

    PubMed

    Zaragozá, Patricia; Fuentes, Ana; Ruiz-Rico, María; Vivancos, José-Luis; Fernández-Segovia, Isabel; Ros-Lis, José V; Barat, José M; Martínez-Máñez, Ramón

    2015-05-15

    The aim of this work was to develop and evaluate a rapid, easy-to-use optoelectronic system for the shelf-life assessment of squid in cold storage. For this purpose, an optoelectronic nose was designed, which consisted of an array containing six sensing materials prepared by combining different dyes and two inorganic supports (aluminium oxide and silica gel). Samples were packaged with the colorimetric array and kept in cold storage for 12 days. Squid spoilage was monitored simultaneously by the colorimetric array and by the physico-chemical and microbial analyses during storage. Samples exceeded the acceptability limits for microbial counts on the third day. PCA analysis carried out with CIELab showed that the colorimetric array was able to discriminate between fresh squid fit for consumption and spoiled squid. The statistical models obtained by PLS, with the optoelectronic nose, successfully predicted CO2 and O2 content in the headspace as well as microbial growth. PMID:25577086

  6. Application of a dc SQUID to rf amplification: NQR

    SciTech Connect

    Hilbert, C.; Clarke, J.; Sleator, T.; Hahn, E.L.

    1985-05-01

    Superconducting QUantum Interference Devices (SQUIDs) have been used for more than a decade for the detection of magnetic resonance. Until recently, these devices had mostly been confined to operation in the audiofrequency range, so that experiments have been restricted to measurements of resonance at low frequencies, or of changes in the static susceptibility of a sample induced by rf irradiation at the resonant frequency. However, the recent extension of the operating range of low noise dc SQUIDs to radiofrequencies (rf) allows one to detect magnetic resonance directly at frequencies up to several hundred megahertz. In this paper, we begin by summarizing the properties of dc SQUIDs as tuned rf amplifers. We then describe first, the development of a SQUID system for the detection of pulsed nuclear quadrupole resonance (NQR) at about 30 MHz and second, a novel technique for observing magnetic resonances in the absence of any externally applied rf fields.

  7. High-T(c) squid application in medicine and geophysics

    NASA Technical Reports Server (NTRS)

    Polushkin, V. N.; Uchaikin, S. V.; Vasiliev, B. V.

    1991-01-01

    In our laboratory of high-T(sub c), a one-hole squid was built from Y1Ba2Cu3O(7-x) ceramics obtained by a standard procedure of solid state reaction. The ceramics with critical current density J(sub c) is greater than 100 A/sq cm was selected. In the middle of a 10 x 10 x 2 mm ceramics pellet, a 0.8 mm hole was drilled in which the superconducting loop of the squid was located. Between the hole and the edge of the pellet, a cut was mechanically filed out with a bridge inside it connecting the superconducting ring. A scheme of the magnetometer is presented. The resonant frequency shift of the tank circuit, the connection of the squid with this circuit, and the squid inductance are evaluated. One of the most interesting fields of the squid-based magnetometer application is biomagnetism, particularly, the human heart magnetocardiogram measuring. The low-temperature squids were used in this area and many interesting and important scientific results have been obtained. The observations have shown that the main noise contribution was not due to the squid but to the Earth's magnetic field variations, industrial inductions, and mainly to the vibrations caused by liquid nitrogen boiling and by vibrations of the box. Further attempts are needed to reduce the magnetic noise inductions. Nevertheless, the estimations promise the maximum signal/noise relation of the high-T(sub c) squid-magnetocardiometer to be not less than 10:1 in a bandwidth of 60 Hz. Apparently, such resolution would be enough not only for steady cardiogram reading but even for thin structure investigation at average technique application.

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

    SciTech Connect

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

    1995-08-01

    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.

  9. High transition-temperature SQUID magnetometers and practical applications

    SciTech Connect

    Dantsker, E

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}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{sub 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{sup {minus}1/2} at 1 Hz and 8.5 fT Hz{sup {minus}1/2} at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz{sup {minus}1/2} at 1 Hz and 18 fT Hz{sup {minus}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.

  10. Fractionation of terrestrial neon by hydrodynamic hydrogen escape from ancient steam atmospheres

    NASA Technical Reports Server (NTRS)

    Zahnle, K.

    1991-01-01

    Atmospheric neon is isotopically heavier than mantle neon. By contrast, nonradiogenic mantle Ar, Kr, and Xe are not known to differ from the atmosphere. These observations are most easily explained by selective neon loss to space; however, neon is much too massive to escape from the modern atmosphere. Steam atmospheres are a likely, if intermittent, feature of the accreting Earth. They occur because, on average, the energy liberated during accretion places Earth above the runaway greenhouse threshold, so that liquid water is not stable at the surface. It is found that steam atmospheres should have lasted some ten to fifty million years. Hydrogen escape would have been vigorous, but abundant heavy constituents would have been retained. There is no lack of plausible candidates; CO2, N2, or CO could all suffice. Neon can escape because it is less massive than any of the likely pollutants. Neon fractionation would have been a natural byproduct. Assuming that the initial Ne-20/Ne-22 ratio was solar, it was found that it would have taken some ten million years to effect the observed neon fractionation in a 30 bar steam atmosphere fouled with 10 bars of CO. Thicker atmospheres would have taken longer; less CO, shorter. This mechanism for fractionating neon has about the right level of efficiency. Because the lighter isotope escapes much more readily, total neon loss is pretty minimal; less than half of the initial neon endowment escapes.

  11. A scanning SQUID microscope with 200 MHz bandwidth

    NASA Astrophysics Data System (ADS)

    Talanov, Vladimir V.; Lettsome, Nesco M., Jr.; Borzenets, Valery; Gagliolo, Nicolas; Cawthorne, Alfred B.; Orozco, Antonio

    2014-04-01

    We developed a scanning DC SQUID microscope with novel readout electronics capable of wideband sensing of RF magnetic fields from 50 to 200 MHz and simultaneously providing closed-loop response at kHz frequencies. To overcome the 20 MHz bandwidth limitation of traditional closed-loop SQUIDs, a flux-modulated closed-loop simultaneously locks the SQUID quasi-static flux and flux-biases the SQUID for amplification of the RF flux up to ?0/4 in amplitude. Demodulating the SQUID voltage with a double lock-in technique yields a signal representative of both the amplitude and phase of the RF flux. This provides 80 dB of a linear dynamic range with a flux noise density of 4 ??0 Hz-1/2 at 200 MHz for a Y Ba2Cu3O7 bi-crystal SQUID at 77 K. We describe the electronics performance and present images for RF magnetic field of the travelling wave in a coplanar waveguide, the standing wave in an open-circuited microstrip, and a surface mounted device antenna.

  12. An investigation of pinch welds using HTS SQUIDs

    NASA Astrophysics Data System (ADS)

    Carr, Chris; Espy, Michelle A.; Urbaitis, Algis V.; Kraus, Robert H., Jr.

    2006-05-01

    To contain high-pressure gases inside a pressure vessel a seal is often made in a thin-walled tube, known as the stem tube, that connects the gas reservoir and the vessel. This seal can be achieved through the use of a resistance pinch weld that forms with only a limited amount of melting occurring. The lack of melting makes applying traditional post-weld nondestructive evaluation (NDE) techniques extremely difficult. The welds of interest here are made from 304L stainless steel (typically 3.8 mm diameter and 38 mm long) and have a non-uniform geometry that does not inherently lend itself to either eddy current or static field SQUID-based measurement techniques. We perform these NDE measurements with both the sample and the SQUID located inside local electromagnetic shielding. SQUID data are presented as individual time series traces for a set of welds that were fabricated using a broad range of fabrication parameters, and a comparison is made between the SQUID-based results and the known parameters. With the limited spatial resolution offered by our present SQUID system, it is not clear if weld quality can be evaluated from purely SQUID-based results.

  13. Discovery of solar wind neon in the Allende meteorite

    NASA Technical Reports Server (NTRS)

    Heymann, D.; Palma, R. L.

    1986-01-01

    Insert gases have been measured in seven sieve fractions of a disaggregated sample of the Allende meteorite. The disaggregation was done by ultrasonic treatment in water and by freeze-thawing. This sample consititutes the first gas-rich portion known to occur in the Allende meteorite. The composition of the trapped neon is solar, i.e., Neon-B, and the gas-rich samples contain more trapped Ne-20 than Ar-36. The set of sieve fractions show an anticorrelation of Ne-20 content and grain size. Gas-richness seems to be quite common among the CV3 meteorites with Allende added to the earlier known cases of Mokoia, Vigarano, and Efremovka.

  14. Discovery of solar wind neon in the Allende meteorite

    NASA Astrophysics Data System (ADS)

    Heymann, D.; Palma, R. L.

    1986-09-01

    Inert gases have been measured in seven sieve fractions of a disaggregated sample of the Allende meteorite. The disaggregation was done by ultrasonic treatment in water and by freeze-thawing. This sample constitutes the first gas-rich portion known to occur in the Allende meteorite. The composition of the trapped neon is solar, i.e., Neon-B, and the gas-rich samples contain more trapped 20Ne than 36Ar. The set of sieve fractions show an anticorrelation of 20Ne content and grain size. Gas-richness seems to be quite common among the CV3 meteorites with Allende added to the earlier known cases of Mokoia, Vigarano, and Efremovka.

  15. Discovery of solar wind neon in the Allende meteorite

    NASA Astrophysics Data System (ADS)

    Heymann, D.; Palma, R. L.

    1986-03-01

    Insert gases have been measured in seven sieve fractions of a disaggregated sample of the Allende meteorite. The disaggregation was done by ultrasonic treatment in water and by freeze-thawing. This sample consititutes the first gas-rich portion known to occur in the Allende meteorite. The composition of the trapped neon is solar, i.e., Neon-B, and the gas-rich samples contain more trapped Ne-20 than Ar-36. The set of sieve fractions show an anticorrelation of Ne-20 content and grain size. Gas-richness seems to be quite common among the CV3 meteorites with Allende added to the earlier known cases of Mokoia, Vigarano, and Efremovka.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Guofeng; Zhang, Yi; Zhang, Shulin; Krause, Hans-Joachim; Wang, Yongliang; Liu, Chao; Zeng, Jia; Qiu, Yang; Kong, Xiangyan; Dong, Hui; Xie, Xiaoming; Offenhusser, Andreas; Jiang, Mianheng

    2012-10-01

    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 ?Hz) in the white noise range in a magnetically shielded room. Using such gradiometer, both MCG and MEG signals are recorded.

  17. Nuclear magnetic resonance with dc SQUID preamplifiers

    SciTech Connect

    Fan, N.Q.; Heaney, M.B.; Clarke, J.; Newitt, D.; Wald, L.L.; Hahn, E.L.; Bielecki, A.; Pines, A.

    1989-03-01

    Sensitive radio-frequency (rf) amplifiers based on dc Superconducting QUantum Intererference Devices (SQUIDSs) 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 /sup 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 x 10/sup 16/ nuclear Bohr magnetons in a single free precession signal with a bandwidth of 10 kHz. In a third experiment, a sample containing /sup 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 /sup 119/Sn nuclei is detected with a tuned amplifier and Q-spoiler, and a single pulse resolution of 10/sup 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 /sup 195/Pt nuclei has been observed at 55 kHz in a field of 60 gauss.

  18. Helium-neon laser improves skin repair in rabbits.

    PubMed

    Peccin, Maria Stella; Renno, Ana Claudia Muniz; de Oliveira, Flavia; Giusti, Paulo Ricardo; Ribeiro, Daniel Araki

    2012-12-01

    The purpose of this study was to evaluate the influence of helium-neon laser on skin injury in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral skin damage in leg. Helium-neon laser light, at a fluence of 6?J?cm2 and wavelength of 632.8?nm, was applied on the left legs (laser group). The right leg lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections. The results showed little infiltration of inflammatory cells, with proliferation of fibroblasts forming a few fibrous connective tissue after 1 week post-injury. The lesion on the 3rd week was characterized by granulation tissue, which formed from proliferated fibrous connective tissue, congested blood vessels and mild mononuclear cell infiltration. On the 5th week, it was observed that debris material surrounded by a thick layer of connective tissue and dense collage, fibroblasts cells present in the dermis covered by a thick epidermal layer represented by keratinized epithelium. Taken together, our results suggest that helium-neon laser is able to improve skin repair in rabbits at early phases of recovery. PMID:23057697

  19. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    SciTech Connect

    Heaney, M.B. . Dept. of Physics Lawrence Berkeley Lab., CA )

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al{sub 2}O{sub 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 {times} 10{sup 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{sub 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.

  20. Retrapping Current in Bridge-Type Nano-SQUIDs

    NASA Astrophysics Data System (ADS)

    Hazra, D.; Kirtley, J. R.; Hasselbach, K.

    2015-08-01

    It is a challenge to fabricate bridge-type nano-superconducting quantum interference devices (bridge-type nano-SQUIDs) that operate without hysteresis over a broad temperature range. Hysteresis—defined by the difference between switching and retrapping current—is one of the foremost constraints to operating nano-SQUIDs with low noise. The quantum behavior of the switching current has been explored in bridge-type nano-SQUIDs, but studies exploring the parameters ruling the retrapping current are rare. Here, we study the temperature and magnetic-field dependence of the retrapping current in two different kinds of bridge-type nano-SQUID: trilayer aluminum-niobium-tungsten bridge-type nano-SQUIDs and suspended-bridge nano-SQUIDs. Our study confirms previous works showing that the retrapping current decreases as the bath temperature increases and is insensitive to the magnetic field. Using a thermal model originally proposed by Skocpol, Beasley, and Tinkham [J. Appl. Phys. 45, 4054 (1974)], we account for, and suggest a simple formula which describes, the temperature dependence of the retrapping current. Our calculations show that the magnitude of the retrapping current is mainly dependent on the superconducting transition temperature and the effective resistance of the weak link and that the temperature dependence of the retrapping current is ruled by the temperature dependence of the thermal conductivity in the normal and superconducting state. Finally, we apply our calculation to newly fabricated shunted bridge-type nano-SQUIDs, which show nonhysteretic current-voltage characteristics down to at least 250 mK and display systematic voltage modulations as a function of externally applied magnetic fields.

  1. Nuclear magnetic resonance experiments with DC SQUID amplifiers

    NASA Astrophysics Data System (ADS)

    Heaney, M. B.

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting Quantum Interference Devices) with Nb/Al2O3/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(exp 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 NaClO3 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.

  2. SQUID detected NMR in microtesla magnetic fields

    NASA Astrophysics Data System (ADS)

    Matlachov, Andrei N.; Volegov, Petr L.; Espy, Michelle A.; George, John S.; Kraus, Robert H.

    2004-09-01

    We have built an NMR system that employs a superconducting quantum interference device (SQUID) detector and operates in measurement fields of 2-25 μT. The system uses a pre-polarizing field from 4 to 30 mT generated by simple room-temperature wire-wound coils that are turned off during measurements. The instrument has an open geometry with samples located outside the cryostat at room-temperature. This removes constraints on sample size and allows us to obtain signals from living tissue. We have obtained 1H NMR spectra from a variety of samples including water, mineral oil, and a live frog. We also acquired gradient encoded free induction decay (FID) data from a water-plastic phantom in the μT regime, from which simple projection images were reconstructed. NMR signals from samples inside metallic containers have also been acquired. This is possible because the penetration skin depth is much greater at the low operating frequencies of this system than for conventional systems. Advantages to ultra-low field NMR measurements include lower susceptibility artifacts caused by high strength polarizing and measurement fields, and negligible line width broadening due to measurement field inhomogeneity, reducing the burden of producing highly homogeneous fields.

  3. Noise measurements in squid axon membrane.

    PubMed

    Fishman, H M; Poussart, D M; Moore, L E

    1975-12-01

    A small area (10(-4) to 10(-5) cm2 patch) of the external surface of a squid (Loligo pealei) axon was "isolated" electrically by means of a pair of concentric glass pipettes and sucrose solution to achieve a low extraneous noise measurement of spontaneous fluctuations in membrane potential and current. The measured "small-signal" impedance function of the isolated patch in seawater was constant at low frequencies and declined monotonically at frequencies beyond 100Hz. It is shown that the power-density spectrum (PDS) of voltage noise, which generally reflects the current-noise spectrum filtered by the membrane impedance function, is equivalent to the power spectrum of current-noise up to frequencies where the impedance decline is significant (Fishman, 1973a, Proc. Nat. Acad. Sci. USA 70:876). This result is in contrast to an impedance resonance measured under uniform constant-current (internal axial wire) conditions, for which the voltage-noise PDS reflects the impedance resonance. The overdamped resonance in the patch technique is a consequence of the relatively low resistance (1 Momega) pathways through the sucrose solution in the interstitial Schwann cell space which surround and shunt the high resistance (10-100 Momega) membrane patch. Current-noise measurements during patch voltage clamp extend observation of patch ion-conductance fluctuations to 1 kHz. Various tests are presented to demonstrate the temporal and spatial adequacey of patch potential control during current-noise measurements. PMID:1214277

  4. On the mechanism of populating 3p levels of neon under pumping by a hard ioniser

    SciTech Connect

    Khasenov, M U

    2011-03-31

    The effect of quenching additives on the luminescence properties of helium - neon mixtures under pumping by {alpha} particles emitted from {sup 210}Po atoms is considered. It is concluded that, under excitation by a heavy charged particle, the population of the 3p'[1/2]{sub 0} level of neon is not related to the dissociative recombination of molecular ions. It is suggested that the most likely channels for populating the 3p level are the excitation transfer from metastable helium atoms to neon atoms and direct excitation of neon by nuclear particles and secondary electrons. (lasers and active media)

  5. Isotopic effects in the neon fixed point: uncertainty of the calibration data correction

    NASA Astrophysics Data System (ADS)

    Steur, Peter P. M.; Pavese, Franco; Fellmuth, Bernd; Hermier, Yves; Hill, Kenneth D.; Seog Kim, Jin; Lipinski, Leszek; Nagao, Keisuke; Nakano, Tohru; Peruzzi, Andrea; Sparasci, Fernando; Szmyrka-Grzebyk, Anna; Tamura, Osamu; Tew, Weston L.; Valkiers, Staf; van Geel, Jan

    2015-02-01

    The neon triple point is one of the defining fixed points of the International Temperature Scale of 1990 (ITS-90). Although recognizing that natural neon is a mixture of isotopes, the ITS-90 definition only states that the neon should be of natural isotopic composition, without any further requirements. A preliminary study in 2005 indicated that most of the observed variability in the realized neon triple point temperatures within a range of about 0.5?mK can be attributed to the variability in isotopic composition among different samples of natural neon. Based on the results of an International Project (EUROMET Project No. 770), the Consultative Committee for Thermometry decided to improve the realization of the neon fixed point by assigning the ITS-90 temperature value 24.5561?K to neon with the isotopic composition recommended by IUPAC, accompanied by a quadratic equation to take the deviations from the reference composition into account. In this paper, the uncertainties of the equation are discussed and an uncertainty budget is presented. The resulting standard uncertainty due to the isotopic effect (k = 1) after correction of the calibration data is reduced to (4 to 40)??K when using neon of natural isotopic composition or to 30??K when using 20Ne. For comparison, an uncertainty component of 0.15?mK should be included in the uncertainty budget for the neon triple point if the isotopic composition is unknown, i.e. whenever the correction cannot be applied.

  6. Coupled non-uniform bi-squid: A numerical investigation

    NASA Astrophysics Data System (ADS)

    Longhini, Patrick; Berggren, Susan; Palacios, Antonio; In, Visarath; Leese de Escobar, Anna

    2012-06-01

    This work investigates through numerical simulations a novel device that improvesdynamic range and linearity. The standard DC SQUID can increase in linearity by adding athird junction, changing to a device known as the bi-SQUID. It is known that the dynamicrange can increase by connecting SQUIDs in series, and it has been shown that nonuniformityin the loops sizes in arrays of SQUIDs can produce a unique 'anti'-peak at thezero magnetic flux (device know as a SQIF). Thus, combining these ideas we can improvethe dynamic range and design a highly linear device with a unique 'anti'-peak. Hence, this device can be referred to as a bi-SQIF or non-uniform bi-SQUID array. Results have shown that the maximum voltage swing increase proportional to N, where N is the number of loops connected in series. The spur free dynamic range also improves as N increases, which is directly related to the linearity of the device. Therefore, we have designed a device which can lead to improvements which can be applicable to low noise amplifier (LNA), and provide a platform for creating "electrically" small antennas.

  7. High-sensitivity SQUIDs with dispersive readout for scanning microscopy

    NASA Astrophysics Data System (ADS)

    Mol, J. M.; Foroughi, F.; Arps, J.; Kammerloher, E.; Bethke, P.; Gibson, G. W., Jr.; Fung, Y. K. K.; Klopfer, B.; Nowack, K.; Kratz, P. A.; Huber, M. E.; Moler, K. A.; Kirtley, J. R.; Bluhm, H.

    2014-03-01

    In a scanning SQUID microscope, the high magnetic flux sensitivity is utilized to image magnetic properties of sample surfaces. As an alternative to the widely used DC SQUIDs, we present Nb SQUIDs for scanning with dispersive microwave readout, featuring significantly higher bandwidth and sensitivity. An on-chip shunt capacitor in parallel with the junction and flux pickup loops forms an LC resonator whose resonance depends on the flux in the SQUID. The readout utilizes a phase-sensitive detection of the reflected drive signal at the SQUID's resonance frequency. Highest sensitivities are achieved by making use of the inherent nonlinearity of the device at high excitation powers. We present a study of the characteristics and noise measurements of our sensors at 4 K. Extrapolations from our results to 300 mK indicate that flux sensitivities as low as 50 n?0Hz- 1 / 2 could be possible. Using high-resolution lithography, our sensors promise sub-micron spatial resolution. Integrated into a scanning microscope, they will provide a powerful tool for the study of weak magnetic effects and quantum coherent phenomena. This work was supported by NSF IMR-MIP grant No. 0957616 and the Alfried Krupp von Bohlen und Halbach - Foundation.

  8. Environmental effects on recreational squid jigging fishery catches

    NASA Astrophysics Data System (ADS)

    Cabanellas-Reboredo, Miguel; Als, Josep; Palmer, Miquel; Morales-Nin, Beatriz

    2012-08-01

    Experimental fishing sessions simulating the operating procedures of the recreational fishery for the European squid that operates at inshore Palma Bay (Balearic Islands, Spain) were conducted to investigate the effects of environmental variables on squid catches. The catch per unit of effort (cpue) of recreational-like jigging sessions showed a seasonal pattern (higher cpue during colder months). Two alternative hypotheses can explain such a pattern. First, squid could migrate inshore during colder months to seek spatio-temporal windows within which the sea temperature maximize spawning success. Second, the timing of the seasonal reproductive peak and the growth rate of any given cohort would result in a higher percentage of squid whose body size is greater than the gear-specific vulnerability threshold during the colder months. The combination of environmental variables that maximized cpue was a low sea surface temperature, a low windspeed, low atmospheric pressure, and days close to the new moon. A specific period of the day, narrowly around sunset, favoured the catches. Within this narrow period, the sunlight is still sufficient to allow the recreational fishing lures to be effective, and the squid have already shifted to a more active pattern of movement characteristic of the night-time period.

  9. Stable Fly Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult stable flies feed on the blood of humans, pets and livestock, inflicting painful bites. Stable flies need one and sometimes two bloodmeals each day to develop their eggs. Unlike mosquitoes where only the females bloodfeed, both male and female stable flies require blood to reproduce. Stable fl...

  10. Patch voltage clamp of squid axon membrane.

    PubMed

    Fishman, H M

    1975-12-01

    A small area (patch) of the external surface of a squid axon can be "isolated" electrically from the surrounding bath by means of a pair of concentric glass pipettes. The seawater-filled inner pipette makes contact with the axon and constitutes the external access to the patch. The outer pipette is used to direct flowing sucrose solution over the area surrounding the patch of membrane underlying the inner pipette. Typically, sucrose isolated patches remain in good condition (spike amplitude greater than 90 mV) for periods of approximately one half hour. Patches of axon membrane which had previously been exposed to sucrose solution were often excitable. Membrane survival of sucrose treatment apparently arises from an outflow of ions from the axon and perhaps satellite cells into the interstitial cell space surrounding the exolemma. Estimate of the total access resistance (electrode plus series resistance) to the patch is about 100 komega (7 omega cm2). Patch capacitance ranges from 10-100 pF, which suggests areas of 10(-4) to 10(-5) cm2 and resting patch resistances of 10-100 Momega. Shunt resistance through the interstitial space exposed to sucrose solution, which isolates the patch, is typically 1-2 Momega. These parameters indicate that good potential control and response times can be achieved on a patch. Furthermore, spatial uniformity is demonstrated by measurement of an exoplasmic isopotential during voltage clamp of an axon patch. The method may be useful for other preparations in which limited membrane area is available or in special instances such as in the measurement of membrane conduction noise. PMID:1214276

  11. Channel equalized DC squid flux-locked loop

    NASA Astrophysics Data System (ADS)

    Gershenson, Meir; McDonald, Robert J.

    1995-02-01

    A DC superconductor quantum interference device (i.e. DC SQUID) is used in a flux-looked loop as a sensitive detector of magnetic flux. Prior art devices of this sort had a transfer function which was frequency-limited by the transfer function of impedance matching circuitry which is used to connect the DC SQUID with the first preamplifier, which amplifies the DC SQUID signal before it is applied to a detector circuit. The present invention corrects this frequency limitation by creating a compensating circuit having a transfer function which is the inverse of that of the impedance matching circuitry and inserting it in the system after the first preamplifier and before the detector circuit.

  12. Microwave SQUID Multiplexer for the Readout of Metallic Magnetic Calorimeters

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Gastaldo, L.; Fleischmann, A.; Enss, C.

    2014-06-01

    We have realized a frequency-domain multiplexing technique for the readout of large metallic magnetic calorimeter detector arrays. It is based on non-hysteretic single-junction SQUIDs and allows for a simultaneous readout of hundreds or thousands of detectors by using a single cryogenic high electron mobility transistor amplifier and two coaxial cables that are routed from room-temperature to the detector array. We discuss the working principle of the multiplexer and present details about our prototype multiplexer design. We show that fabricated devices are fully operational and that characteristic SQUID parameters such as the input sensitivity of the SQUID or the resonance frequency of the readout circuit can be predicted with confidence. Our best device so far has shown a magnetic flux white noise level of 1.4 m which can in future be reduced by an optimization of the fabrication processes as well as an improved microwave readout system.

  13. Application of SQUIDs for registration of biomagnetic signals

    NASA Astrophysics Data System (ADS)

    Voitovych, I. D.; Primin, M. A.; Sosnytskyy, V. N.

    2012-04-01

    Supersensitive magnetometric systems based on low-temperature SQUIDs have been designed to conduct research in cardiology (magnetocardiography) and to examine distribution of magnetic nanoparticles in biologic objects. Such SQUID magnetometric systems are distinguished by their noise immunity enabling research in nonscreened rooms. High repeatability of research outcomes has been confirmed. The use of magnetocardiographic systems has permitted a new screening information technology to be developed to diagnose heart diseases at early stages. Magnetic imaging of heart's action currents is an ideal way to test local electrical heterogeneity of myocardium. It is shown that magnetocardiography has a significant potential for both basic science of analysis of heart's biosignals and clinical cardiologic practice. A SQUID magnetometric system measuring magnetic signals radiated by the organs of laboratory animals is described. Information technology for automatic recording and transforming magnetometric data has been developed; the measurement of signals over rats' livers while injecting intravenously the nanoparticles of iron oxides and lead solutions are presented.

  14. Signal detection in l/f noise of SQUID magnetometers

    NASA Technical Reports Server (NTRS)

    Cabrera, B.; Anderson, J. T.

    1978-01-01

    It is shown that the variance on the SQUID power spectrum in the l/f low frequency region is well behaved, i.e., any small frequency band may be treated as white noise in standard power spectrum estimation theory. Specifically a calibration signal is examined at 0.017 Hz with an equivalent energy referred to the SQUID input coil of 1 times 10 to the -30th J and a digitally recorded and analyzed record of 140 hr duration obtained an optimum S/N better than 400. The results are in good agreement with theory. In addition no deviation from the l/f dependence of the noise energy spectrum is seen down to frequencies below 10 to the -5th Hz. A commercially available SQUID and electronics system were used.

  15. NMR/MRI with hyperpolarized gas and high Tc SQUID

    DOEpatents

    Schlenga, Klaus (Eggenstein, DE); de Souza, Ricardo E. (Recife, BR); Wong-Foy, Annjoe (Berkeley, CA); Clarke, John (Berkeley, CA); Pines, Alexander (Berkeley, CA)

    2000-01-01

    A method and apparatus for the detection of nuclear magnetic resonance (NMR) signals and production of magnetic resonance imaging (MRI) from samples combines the use of hyperpolarized inert gases to enhance the NMR signals from target nuclei in a sample and a high critical temperature (Tc) superconducting quantum interference device (SQUID) to detect the NMR signals. The system operates in static magnetic fields of 3 mT or less (down to 0.1 mT), and at temperatures from liquid nitrogen (77K) to room temperature. Sample size is limited only by the size of the magnetic field coils and not by the detector. The detector is a high Tc SQUID magnetometer designed so that the SQUID detector can be very close to the sample, which can be at room temperature.

  16. 77 FR 74159 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    ... Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan (FMP) (75 FR 11441, March 11, 2010) as a... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Framework Adjustment 7 AGENCY... on the longfin squid fishery from a catch cap to a discard cap in Framework Adjustment 7 to...

  17. Improved Readout Scheme for SQUID-Based Thermometry

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin

    2007-01-01

    An improved readout scheme has been proposed for high-resolution thermometers, (HRTs) based on the use of superconducting quantum interference devices (SQUIDs) to measure temperature- dependent magnetic susceptibilities. The proposed scheme would eliminate counting ambiguities that arise in the conventional scheme, while maintaining the superior magnetic-flux sensitivity of the conventional scheme. The proposed scheme is expected to be especially beneficial for HRT-based temperature control of multiplexed SQUIDbased bolometer sensor arrays. SQUID-based HRTs have become standard for measuring and controlling temperatures in the sub-nano-Kelvin temperature range in a broad range of low-temperature scientific and engineering applications. A typical SQUIDbased HRT that utilizes the conventional scheme includes a coil wound on a core made of a material that has temperature- dependent magnetic susceptibility in the temperature range of interest. The core and the coil are placed in a DC magnetic field provided either by a permanent magnet or as magnetic flux inside a superconducting outer wall. The aforementioned coil is connected to an input coil of a SQUID. Changes in temperature lead to changes in the susceptibility of the core and to changes in the magnetic flux detected by the SQUID. The SQUID readout instrumentation is capable of measuring magnetic-flux changes that correspond to temperature changes down to a noise limit .0.1 nK/Hz1/2. When the flux exceeds a few fundamental flux units, which typically corresponds to a temperature of .100 nK, the SQUID is reset. The temperature range can be greatly expanded if the reset events are carefully tracked and counted, either by a computer running appropriate software or by a dedicated piece of hardware.

  18. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John (Berkeley, CA); Pines, Alexander (Berkeley, CA); McDermott, Robert F. (Monona, WI); Trabesinger, Andreas H. (London, GB)

    2008-12-16

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  19. Spins on Metals: Noise in SQUIDs and Spin Glasses

    NASA Astrophysics Data System (ADS)

    Chen, Zhi; Yu, Clare

    2010-03-01

    Recent experiments at Stanford and Wisconsin have found evidence for magnetic defects on the surface of elemental metals like aluminum, niobium, and gold. Fluctuations of these impurities are the source of flux noise in SQUIDs. Flux noise is a major obstacle to the realization of using superconducting qubits to construct quantum computers. To see if flux noise can be described by spin glass noise, we have used Monte Carlo simulations of a 3D Ising spin glass to produce noise. We find that the noise is a maximum at the critical temperature. We compare our results to experimental measurements of the susceptibility, as well as the flux and inductance noise measured in SQUIDs.

  20. Possible physical mechanisms of stochastic oscillations in RF SQUID's

    SciTech Connect

    Dmitrenko, I.M.; Konotop, D.A.; Tsoi, G.M.; Shnyrkov, V.I.

    1985-03-01

    The processes of giant noise generation in RF SQUID's are studied experimentally. It is shown that the appearance of stochastic oscillations is due to different retardation mechanisms in a dynamic system, depending on the characteristics of the Josephson junctions and the external excitation. The retardation times in the SQUID's studied were determined by the recharging of the Josephson-junction capacitance (tau/sub R//sub C/), by quasiparticle relaxation processes (tau/sub epsilon-c/), and by the relaxation time of thermal processes in the junction (tau/sub T/).

  1. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    2006-05-30

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  2. SQUID detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    2006-10-03

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  3. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John (Berkeley, CA); McDermott, Robert (Louisville, CO); Pines, Alexander (Berkeley, CA); Trabesinger, Andreas Heinz (CH-8006 Zurich, CH)

    2007-05-15

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  4. Scanning high-Tc SQUID imaging system for magnetocardiography

    NASA Astrophysics Data System (ADS)

    Yang, Hong-Chang; Wu, Tsung-Yeh; Horng, Herng-Er; Wu, Chau-Chung; Yang, S. Y.; Liao, Shu-Hsien; Wu, Chiu-Hsien; Jeng, J. T.; Chen, J. C.; Chen, Kuen-Lin; Chen, M. J.

    2006-05-01

    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-Tc (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 ?-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.

  5. TOPICAL REVIEW: Radio-frequency amplifiers based on dc SQUIDs

    NASA Astrophysics Data System (ADS)

    Mück, Michael; McDermott, Robert

    2010-09-01

    SQUIDs are an attractive candidate for the amplification of low-level rf and microwave signals. Compared to semiconductor amplifiers, they offer lower noise and much lower power dissipation. Especially at frequencies below 1 GHz, the improvement in noise temperature compared to the best cold semiconductor amplifiers can be as high as 50; noise temperatures only slightly above the quantum limit have been achieved in this frequency range. This article will review the current status of radio-frequency amplifiers based on dc SQUIDs and provide detailed discussions of amplifier noise temperature, input and output impedance, and nonlinearities.

  6. Isolation and characterization of collagen from squid ( Ommastrephes bartrami) skin

    NASA Astrophysics Data System (ADS)

    Yan, Mingyan; Li, Bafang; Zhao, Xue

    2009-06-01

    Collagen of squid ( Ommastrephes bartrami) skin was examined in the present study. Histology showed that collagen fiber in the skin was partially cross-linked with muscle fiber. Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the skin and characterized. The results of amino acid composition and electrophoretic patterns revealed that ASC and PSC were both type I collagen, containing ?1 and ?2 chains. FTIR (fourier transform infrared spectroscopy) investigations confirmed the existence of helical arrangements in PSC of squid skin. The denaturation temperature (Td) and shrinkage temperature (Ts) of PSC were 29.4C and 52.8C, respectively.

  7. Swimming dynamics and propulsive efficiency of squids throughout ontogeny.

    PubMed

    Bartol, Ian K; Krueger, Paul S; Thompson, Joseph T; Stewart, William J

    2008-12-01

    Squids encounter vastly different flow regimes throughout ontogeny as they undergo critical morphological changes to their two locomotive systems: the fins and jet. Squid hatchlings (paralarvae) operate at low and intermediate Reynolds numbers (Re) and typically have rounded bodies, small fins, and relatively large funnel apertures, whereas juveniles and adults operate at higher Re and generally have more streamlined bodies, larger fins, and relatively small funnel apertures. These morphological changes and varying flow conditions affect swimming performance in squids. To determine how swimming dynamics and propulsive efficiency change throughout ontogeny, digital particle image velocimetry (DPIV) and kinematic data were collected from an ontogenetic range of long-finned squid Doryteuthis pealeii and brief squid Lolliguncula brevis swimming in a holding chamber or water tunnel (Re = 20-20 000). Jet and fin wake bulk properties were quantified, and propulsive efficiency was computed based on measurements of impulse and excess kinetic energy in the wakes. Paralarvae relied predominantly on a vertically directed, high frequency, low velocity jet as they bobbed up and down in the water column. Although some spherical vortex rings were observed, most paralarval jets consisted of an elongated vortical region of variable length with no clear pinch-off of a vortex ring from the trailing tail component. Compared with paralarvae, juvenile and adult squid exhibited a more diverse range of swimming strategies, involving greater overall locomotive fin reliance and multiple fin and jet wake modes with better defined vortex rings. Despite greater locomotive flexibility, jet propulsive efficiency of juveniles/adults was significantly lower than that of paralarvae, even when juvenile/adults employed their highest efficiency jet mode involving the production of periodic isolated vortex rings with each jet pulse. When the fins were considered together with the jet for several juvenile/adult swimming sequences, overall propulsive efficiency increased, suggesting that fin contributions are important and should not be overlooked in analyses of the swimming performance of squids. The fins produced significant thrust and consistently had higher propulsive efficiency than did the jet. One particularly important area of future study is the determination of coordinated jet/fin wake modes that have the greatest impact on propulsive efficiency. Although such research would be technically challenging, requiring new, powerful, 3D approaches, it is necessary for a more comprehensive assessment of propulsive efficiency of the squid dual-mode locomotive system. PMID:21669828

  8. Optimizing Sampling Efficiency for Biomass Estimation Across NEON Domains

    NASA Astrophysics Data System (ADS)

    Abercrombie, H. H.; Meier, C. L.; Spencer, J. J.

    2013-12-01

    Over the course of 30 years, the National Ecological Observatory Network (NEON) will measure plant biomass and productivity across the U.S. to enable an understanding of terrestrial carbon cycle responses to ecosystem change drivers. Over the next several years, prior to operational sampling at a site, NEON will complete construction and characterization phases during which a limited amount of sampling will be done at each site to inform sampling designs, and guide standardization of data collection across all sites. Sampling biomass in 60+ sites distributed among 20 different eco-climatic domains poses major logistical and budgetary challenges. Traditional biomass sampling methods such as clip harvesting and direct measurements of Leaf Area Index (LAI) involve collecting and processing plant samples, and are time and labor intensive. Possible alternatives include using indirect sampling methods for estimating LAI such as digital hemispherical photography (DHP) or using a LI-COR 2200 Plant Canopy Analyzer. These LAI estimations can then be used as a proxy for biomass. The biomass estimates calculated can then inform the clip harvest sampling design during NEON operations, optimizing both sample size and number so that standardized uncertainty limits can be achieved with a minimum amount of sampling effort. In 2011, LAI and clip harvest data were collected from co-located sampling points at the Central Plains Experimental Range located in northern Colorado, a short grass steppe ecosystem that is the NEON Domain 10 core site. LAI was measured with a LI-COR 2200 Plant Canopy Analyzer. The layout of the sampling design included four, 300 meter transects, with clip harvests plots spaced every 50m, and LAI sub-transects spaced every 10m. LAI was measured at four points along 6m sub-transects running perpendicular to the 300m transect. Clip harvest plots were co-located 4m from corresponding LAI transects, and had dimensions of 0.1m by 2m. We conducted regression analyses with LAI and clip harvest data to determine whether LAI can be used as a suitable proxy for aboveground standing biomass. We also compared optimal sample sizes derived from LAI data, and clip-harvest data from two different size clip harvest areas (0.1m by 1m vs. 0.1m by 2m). Sample sizes were calculated in order to estimate the mean to within a standardized level of uncertainty that will be used to guide sampling effort across all vegetation types (i.e. estimated within 10% with 95% confidence). Finally, we employed a Semivariogram approach to determine optimal sample size and spacing.

  9. Nonlinear dynamics modulation in a neon glow discharge plasma

    NASA Astrophysics Data System (ADS)

    Miller, Paul M.

    In dynamics modulation, two modes in a driven neon glow discharge alternate as the dominant mode as their response to the driving force alternates between spatiotemporal and temporal periodic pulling. This phenomenon was first noted by Koepke, Weltmann, and Selcher (Bull. Am. Phys. Soc. 40, 1716 (1995)), who saw two limited but representative cases and proposed a mechanism (Phys. Rev. E 62, 2773 (2000)) by which it occurs. The intent of this dissertation is to document experimentally and test the dynamics modulation mechanism they proposed. Using a new extension of a previous mathematical treatment of periodic pulling, the resulting experimental data are used to verify the predicted mechanism. A numerical model is also presented that reproduces the signature of dynamics modulation and further supports the validity of the mechanism. For two pairs of mode frequencies, three complete data series as driving frequency is increased are presented. Each of these data series shows the progression of the system from pure spatiotemporal behavior, through dynamics modulation, and ending at entrainment in the upper mode. Ionization wave modes are examined using time series recorded using a photodiode with a narrow band filter that selectively passes the primary neon spectral line at 640 nm. The system was periodically driven using a narrow-band ring dye laser tuned to a wavelength near the metastable neon transition at 588.35 nm. The amplitude of the driving force was decreased (increased) by tuning the laser away from (nearer to) the center of the neon line, while the driving frequency was controlled by an acousto-optic modulator chopping the laser beam at the desired frequency. Arnol'd tongue boundaries identifying the edges of frequency entrainment regions in the driving amplitude-driving frequency plane were established for four different discharge currents. The (upward) dynamics modulation behavior seen by Koepke, Weltmann, and Selcher was reproduced and additional data were acquired for two additional representative cases of downward modulations, previously undocumented. The upward modulations are used to verify the mechanism, while the downward modulations exhibit qualitatively different behavior. These differences are discussed. Two coupled van der Pol equations were chosen to model the mechanism described by Koepke, Weltmann, and Selcher, and the resulting time series was solved with a Runge-Kutta routine whose parameters could be adjusted as the simulation proceeded. The model successfully reproduces the qualitative behavior of dynamics modulation and reinforces the experimental verification of the proposed mechanism, but lacks sufficient complexity for a complete quantitative comparison.

  10. Noble gases in diamonds - Occurrences of solarlike helium and neon

    NASA Technical Reports Server (NTRS)

    Honda, M.; Reynolds, J. H.; Roedder, E.; Epstein, S.

    1987-01-01

    Seventeen diamond samples from diverse locations were analyzed for the contents of He, Ar, Kr, and Xe, and of their isotopes, using a Reynolds (1956) type glass mass spectrometer. The results disclosed a large spread in the He-3/He-4 ratios, ranging from values below atmospheric to close to the solar ratio. In particular, solarlike He-3/He-4 ratios were seen for an Australian colorless diamond composite and an Arkansas diamond, which also displayed solarlike neon isotopic ratios. Wide variation was also observed in the He-4/Ar-40 ratios, suggesting a complex history for the source regions and the diamond crystallization processes.

  11. Effect of neon plasma pre-irradiation on surface morphology and deuterium retention of tungsten

    NASA Astrophysics Data System (ADS)

    Cheng, L.; De Temmerman, G.; Zeijlmans van Emmichoven, P. A.; Ji, G.; Zhou, H. B.; Wang, B.; Yuan, Y.; Zhang, Y.; Lu, G. H.

    2015-08-01

    Neon and deuterium plasma irradiation of polycrystalline tungsten targets have been performed at high fluxes of ?1024 ions m-2 s-1 to study the interaction of neon with tungsten and the influence of neon on deuterium retention. Tungsten exposure to neon plasma leads to the formation of wavy nanostructures on the surface. Subsequent exposure to high-flux deuterium plasma leads to blister formation of micrometer size on top of the wavy structures. The total deuterium retention is decreased by neon pre-irradiation for all surface temperatures used in the present experiments. It is suggested that a barrier of trapped Ne is formed that interrupts the D transport and reduces D retention.

  12. Atomistic simulations of tungsten surface evolution under low-energy neon implantation

    NASA Astrophysics Data System (ADS)

    Backman, Marie; Hammond, Karl D.; Sefta, Faiza; Wirth, Brian D.

    2016-04-01

    Tungsten is a candidate material for the divertor of fusion reactors, where it will be subject to a high flux of particles coming from the fusion plasma as well as a significant heat load. Under helium plasma exposure in fusion-reactor-like conditions, a nanostructured morphology is known to form on the tungsten surface in certain temperature and incident energy ranges, although the formation mechanism is not fully established. A recent experimental study (Yajima et al 2013 Plasma Sci. Technol. 15 282–6) using neon or argon exposure did not produce similar nanostructure. This article presents molecular dynamics simulations of neon implantation in tungsten aimed at investigating the surface evolution and elucidating the role of noble gas mass in fuzz formation. In contrast to helium, neon impacts can sputter both tungsten and previously implanted neon atoms. The shorter range of neon ions, along with sputtering, limit the formation of large bubbles and likely prevents nanostructure formation.

  13. Fly ash carbon passivation

    DOEpatents

    La Count, Robert B; Baltrus, John P; Kern, Douglas G

    2013-05-14

    A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

  14. Development of a Two-Dimensional Micro-SQUID Array for Investigation of Magnetization Spatial Distribution

    NASA Astrophysics Data System (ADS)

    Sakuma, Daisuke; Shinozaki, Tomoya; Nago, Yusuke; Ishiguro, Ryosuke; Kashiwaya, Satoshi; Nomura, Shintaro; Kono, Kimitoshi; Takayanagi, Hideaki

    2016-03-01

    We developed a two-dimensional array of superconducting quantum interference devices (SQUIDs) for investigation of fine spatial distribution of magnetization in superconducting Sr2 RuO4 . Micrometer-sized SQUIDs based on homogeneously formed Al/AlOx /Al tunnel-type Josephson junctions were fabricated using shadow evaporation technique. Unnecessary electrodes formed by the shadow evaporation were removed by inductively coupled plasma reactive ion etching, in order to realize a dense array of SQUIDs. We measured the magnetic modulation of the maximum Josephson current of each SQUID in the array and evaluated the interaction among the SQUIDs.

  15. Two Methods for a First Order Hardware Gradiometer Using Two HTS SQUID's

    SciTech Connect

    Espy, M.A.; Flynn, E.R.; Kraus, R.H., Jr.; Matlachov, A.

    1998-09-15

    Two different systems for noise cancellation (first order gradiometers) have been developed using two similar high temperature superconducting (HTS) SQUIDs. ''Analog'' gradiometry is accomplished in hardware by either (1) subtracting the signals from the sensor and background SQUIDs at a summing amplifier (parallel technique) or (2) converting the inverted background SQUID signal to a magnetic field at the sensor SQUID (series technique). Balance levels achieved are 2000 and 1000 at 20 Hz for the parallel and series methods respectively. The balance level as a function of frequency is also presented. The effect which time delays in the two sets of SQUID electronics have on this balance level is presented and discussed.

  16. Two methods for a first order hardware gradiometer using two HTS SQUIDs

    SciTech Connect

    Espy, M.A.; Flynn, E.R.; Kraus, R.H. Jr.; Matlachov, A.

    1998-12-31

    Two different systems for noise cancellation (first order gradiometers) have been developed using two similar high temperature superconducting (HTS) SQUIDs. Analog gradiometry is accomplished in hardware by either (1) subtracting the signals from the sensor and background SQUIDs at a summing amplifier (parallel technique) or (2) converting the inverted background SQUID signal to a magnetic field at the sensor SQUID (series technique). Balance levels achieved are 2000 and 1000 at 20 Hz for the parallel and series methods respectively. The balance level as a function of frequency is also presented. The effect which time delays in the two sets of SQUID electronics have on this balance level is presented and discussed.

  17. Observations on the spawning behavior, egg masses and paralarval development of the ommastrephid squid Todarodes pacificus in a laboratory mesocosm.

    PubMed

    Puneeta, Pandey; Vijai, Dharmamony; Yoo, Hae-Kyun; Matsui, Hajime; Sakurai, Yasunori

    2015-12-01

    The spawning behavior of ommastrephid squids has never been observed under natural conditions. Previous laboratory observations of Japanese flying squid (Todarodes pacificus) suggest that pre-spawning females might rest on the continental shelf or slope before they ascend above the pycnocline to spawn, and that the egg masses might settle in the pycnocline. Here, two mesocosm experiments were conducted in a 300 m(3) tank that was 6 m deep to investigate this hypothesis. In the first experiment, a thermocline (2.5-3.5 m) was established in the tank by creating a thermally stratified (17-22°C) water column. In the second experiment, the temperature was uniform (22°C) at all depths. Prior to spawning, females did not rest on the tank floor. In the stratified water column, egg masses remained suspended in the thermocline, but in an unstratified water column, they settled on the tank bottom, collapsed and were infested by microbes, resulting in abnormal or nonviable embryos. Eleven females spawned a total of 18 egg masses (17-80 cm in diameter), indicating that females can spawn more than once when under stress. Paralarvae hatched at stage 30/31 and survived for up to 10 days, allowing us to observe the most advanced stage of paralarvae in captivity. Paralarvae survived after consumption of the inner yolk, suggesting they might have fed in the tank. PMID:26632456

  18. New Design of Neon Refrigerator for Hts Power Machines

    NASA Astrophysics Data System (ADS)

    Yoshida, S.; Hirai, H.; Takaike, A.; Hirokawa, M.; Aizawa, Y.; Kamioka, Y.; Okamoto, H.; Hayashi, H.; Shiohara, Y.

    2010-04-01

    In 2007, we developed a prototype refrigerator with a small turbo-expander to provide adequate cooling power (2 kW at 70 K) for HTS (High Temperature Superconductor) power machines. The reverse-Brayton cycle with neon gas as a working fluid was adopted in the refrigerator. The prototype refrigerator does not have enough COP (Coefficient of Performance) for practical HTS applications, and the purpose of this study is to research the information required for designing a new neon refrigerator with improved performance. We take the same refrigeration cycle and working fluid as the prototype one adopted, but a lower process pressure of 1 MPa/0.5 MPa is chosen instead of 2 MPa/1 MPa. The lower process pressure is required by the turbo-compressor design and the refrigeration process is analyzed by using a newly developed process simulator. Also, a heat-exchanger configuration is studied to make the refrigerator size small. The new refrigerator will have a cooling power of 2.5 kW at 65 K, and a COP of 0.06 at 80 K.

  19. Infrared spectra of small molecular ions trapped in solid neon

    SciTech Connect

    Jacox, Marilyn E.

    2015-01-22

    The infrared spectrum of a molecular ion provides a unique signature for that species, gives information on its structure, and is amenable to remote sensing. It also serves as a comparison standard for refining ab initio calculations. Experiments in this laboratory trap molecular ions in dilute solid solution in neon at 4.2 K in sufficient concentration for observation of their infrared spectra between 450 and 4000 cm{sup !1}. Discharge-excited neon atoms produce cations by photoionization and/or Penning ionization of the parent molecule. The resulting electrons are captured by other molecules, yielding anions which provide for overall charge neutrality of the deposit. Recent observations of ions produced from C{sub 2}H{sub 4} and BF{sub 3} will be discussed. Because of their relatively large possibility of having low-lying excited electronic states, small, symmetric molecular cations are especially vulnerable to breakdown of the Born-Oppenheimer approximation. Some phenomena which can result from this breakdown will be discussed. Ion-molecule reaction rates are sufficiently high that in some systems absorptions of dimer cations and anions are also observed. When H{sub 2} is introduced into the system, the initially-formed ion may react with it. Among the species resulting from such ion-molecule reactions that have recently been studied are O{sub 4}{sup +}, NH{sub 4}{sup +}, HOCO{sup +}, and HCO{sub 2}{sup !}.

  20. NEON: Transforming Environmental Data into Free, Open Information

    NASA Astrophysics Data System (ADS)

    Wee, B.

    2010-12-01

    The National Ecological Observatory Network (NEON) will collect data across the United States on the impacts of climate change, land use change and invasive species on natural resources and biodiversity. NEON is a project of the U.S. National Science Foundation (NSF), with many other U.S. agencies and NGOs cooperating. The Observatory’s construction plans call for 60 sites distributed across 20 ecoclimatic Domains. Data will be collected from strategically selected sites within each Domain and synthesized into information products that can be used to describe changes in the nation’s ecosystem through space and time. Sites are arrayed across different land-use types in order to understand large-scale environmental drivers affect biodiversity, ecohydrology, biogeochemistry, and disease ecology across the US continent. NEON is an instrument that listens to the pulse of the US continental ecosystem: infrastructure deployed at these sites will collect an average of over 500 primary measurements at each site, including annual high-resolution airborne LiDAR and hyperspectral data. These primary measurements will be transformed by a state-of-the-art cyberinfrastruture into over 100 higher-order data products. All measurements, data products, algorithms used to compute the data products, and protocols used to collect the primary measurements will be freely available to the public and assessable over the internet. The information products, including selected socio-economic datasets from cooperating Federal agencies, will be served in standard formats, grid-sizes, and geographical projections. This type of information is anticipated to have a wide range of uses, including ecological forecasting, education, public engagement, socio-economic analyses, decision support for climate-change adaptation and mitigation, resource management, and environmental risk management. Open data, interoperability, an open and integrated observation infrastructure, public engagement, and a deliberate approach to making sure that research data can be repurposed for operational purposes are the cornerstones of the NEON strategy: they facilitate the repurposing of credible, reliable data and information for multiple purposes. Often, the same data is useful in an undergraduate course on correlations as it is for public discourse on the effects of increased precipitation on stream water quality. This suggests a strategy for evolving an ecosystem of institutions whose primary responsibility is contributing to an open information commons that creates and curates credible sources of data and information products with clearly documented provenance, quality protocols, uncertainty estimates, and other qualitative descriptors. This information commons is deliberately designed to be tapped by another ecosystem of institutions whose individual missions revolve around some combination of discovery (e.g. research, forecasting, innovation), learning (e.g. public engagement, informal and formal learning, education research), and solutions (e.g. science and technology policy). This talk explores how the NEON information commons is envisioned to interact with this other community of institutions, and how the cornerstone principles enable that community to better focus their creative capabilities around their respective core missions.

  1. NEON, Establishing a Standardized Network for Groundwater Observations

    NASA Astrophysics Data System (ADS)

    Fitzgerald, M.; Schroeter, N.; Goodman, K. J.; Roehm, C. L.

    2013-12-01

    The National Ecological Observatory Network (NEON) is establishing a standardized set of data collection systems comprised of in-situ sensors and observational sampling to obtain data fundamental to the analysis of environmental change at a continental scale. NEON will be collecting aquatic, terrestrial, and atmospheric data using Observatory-wide standardized designs and methods via a systems engineering approach. This approach ensures a wealth of high quality data, data algorithms, and models that will be freely accessible to all communities such as academic researchers, policy makers, and the general public. The project is established to provide 30 years of data which will enable prediction and forecasting of drivers and responses of ecological change at scales ranging from localized responses through regional gradients and up to the continental scale. The Observatory is a distributed system of sites spread across the United States, including Alaska, Hawaii, and Puerto Rico, which is subdivided into 20 statistically unique domains, based on a set of 18 ecologically important parameters. Each domain contains at least one core aquatic and terrestrial site which are located in unmanaged lands, and up to 2 additional sites selected to study domain specific questions such as nitrogen deposition gradients and responses of land use change activities on the ecosystem. Here, we present the development of NEON's groundwater observation well network design and the timing strategy for sampling groundwater chemistry. Shallow well networks, up to 100 feet in depth, will be installed at NEON aquatic sites and will allow for observation of localized ecohydrologic site conditions, by providing basic spatio-temporal near-real time data on groundwater parameters (level, temperature, conductivity) collected from in situ high-resolution instrumentation positioned in each well; and biannual sampling of geochemical and nutrient (N and P) concentrations in a subset of wells for each site. These data will be used to calculate several higher level data products such as hydrologic gradients which drive nutrient fluxes and their change over time. When coupled with other NEON data products, these data will allow for examining surface water/groundwater interactions as well as additional terrestrial and aquatic linkages, such as riparian vegetation response to changing ecohydrologic conditions (i.e. groundwater withdraw for irrigation, land use change) and natural sources (i.e. drought and changing precipitation patterns). This work will present the well network arrays designed for the different types of aquatic sites (1st/2nd order streams, larger rivers, and lakes) including variations on the well network designs for sites where physical constraints hinder a consistent design due to topographic (steep topography, wetlands) or physical constraints (such as permafrost). A generalized sampling strategy for each type of environment will also be detailed indicating the time of year, largely governed by hydrologic conditions, when sampling should take place to provide consistent groundwater chemistry data to allow for analyzing geochemical trends spatially across the network and through time.

  2. Development of nano and micro SQUIDs based on Al tunnel junctions

    NASA Astrophysics Data System (ADS)

    Ishiguro, Ryosuke; Watanabe, Eiichiro; Sakuma, Daisuke; Shinozaki, Tomoya; Tsuchiya, Shogo; Nago, Yusuke; Osato, Hirotaka; Tsuya, Daiju; Kashiwaya, Hiromi; Kashiwaya, Satoshi; Nomura, Shintaro; Takayanagi, Hideaki; Maeno, Yoshiteru

    2014-12-01

    Superconducting quantum interference devices (SQUIDs) with nano (micro)-meter dimensions are called nano (micro)-SQUIDs. The high sensitivity for flux and position of nano (micro)-SQUIDs can be applied to detect local magnetic fields induced by vortices and the magnetization of mesoscopic superconductors. Nano-SQUIDs based on carbon-nanotube junctions and niobium weak junctions are well known. However, such nano-SQUIDs are not suitable for large-scale integrated circuits and mass production. Therefore, we employ a combination of lithography using the Niemeyer-Dolan technique and the inductively coupled plasma reactive-ion etching technique to fabricate nano-SQUIDs. Here, we report the fabrication of nano (micro)-SQUIDs based on superconducting aluminum tunnel junctions and their application for vortex formation into mesoscopic chiral superconducting Sr2RuO4[1-3].

  3. Scanning SQUID-on-tip microscopy of vortex matter

    NASA Astrophysics Data System (ADS)

    Anahory, Yonathan; Embon, Lior; Vasyukov, Denis; Cuppens, Jo; Lachman, Ella; Halbertal, Dorri; Yaakobi, Elad; Uri, Aviram; Myasoedov, Yuri; Rappaport, Michael L.; Huber, Martin E.; Zeldov, Eli; Weizmann Institute of Science Team; University of Colorado at Denver Team

    2014-03-01

    We present a scanning nanoSQUID microscope with record spatial resolution, spin sensitivity, and operating magnetic fields for the study of vortex matter. The key element of the microscope is the SQUID-on-tip (SOT) device, which is fabricated by pulling a quartz tube into a sharp pipette, followed by three steps of thermal evaporation of a thin superconducting film onto the sides and the apex of the pipette. The devices operate at 4.2 K in applied fields of up to 1T and can be made with diameters down to 50 nm. The SQUIDs-on-tip display an extremely low flux noise of ?n = 50 n?0/Hz1/2 and corresponding spin sensitivity of better than 1 ?B/Hz1/2, which is about two orders of magnitude improvement over any previous SQUID. Using this new tool we have investigated static and dynamic behavior of vortices in superconducting Pb films. By driving ac and dc transport current we can study vortex displacement and the vortex potential landscape with sub-atomic precision. Azrieli and Minerva Foundation, FQRNT(Quebec), ERC (Europe)

  4. HfTi-nanoSQUID gradiometers with high linearity

    NASA Astrophysics Data System (ADS)

    Bechstein, S.; Ruede, F.; Drung, D.; Storm, J.-H.; Kieler, O. F.; Kohlmann, J.; Weimann, T.; Schurig, T.

    2015-02-01

    We have developed a family of HfTi nanoSQUID gradiometers for different applications. These Nb-based nanoSQUIDs contain overdamped superconductor-normal conductor-superconductor (SNS) Josephson junctions with HfTi as a normal conducting barrier. The lateral dimensions of the junctions are about 200 nm × 200 nm, and the barrier thickness is nominally 30 nm. In order to enhance their practical use, the nanoSQUIDs are implemented with gradiometric SQUID and feedback loops, gradiometric transformers, and rf filters. The devices can be operated in an excitation field of up to a few mT with very low levels of nonlinearity. Due to the small loop size and the resulting low loop inductance, a white noise level down to 110 nΦ0/√Hz was achieved. The 1/f noise with a typical corner frequency below 1 kHz is dominated by critical current fluctuations. It can be reduced by applying bias reversal. A noise level of 600 nΦ0/√Hz was achieved at 1 Hz in a two-stage flux locked loop with bias reversal.

  5. Vampire squid: detritivores in the oxygen minimum zone

    PubMed Central

    Hoving, Hendrik J. T.; Robison, Bruce H.

    2012-01-01

    Vampire squid (Vampyroteuthis infernalis) are considered phylogenetic relics with cephalopod features of both octopods and squids. They lack feeding tentacles, but in addition to their eight arms, they have two retractile filaments, the exact functions of which have puzzled scientists for years. We present the results of investigations on the feeding ecology and behaviour of Vampyroteuthis, which include extensive in situ, deep-sea video recordings from MBARI's remotely operated vehicles (ROVs), laboratory feeding experiments, diet studies and morphological examinations of the retractile filaments, the arm suckers and cirri. Vampire squid were found to feed on detrital matter of various sizes, from small particles to larger marine aggregates. Ingested items included the remains of gelatinous zooplankton, discarded larvacean houses, crustacean remains, diatoms and faecal pellets. Both ROV observations and laboratory experiments led to the conclusion that vampire squid use their retractile filaments for the capture of food, supporting the hypothesis that the filaments are homologous to cephalopod arms. Vampyroteuthis' feeding behaviour is unlike any other cephalopod, and reveals a unique adaptation that allows these animals to spend most of their life at depths where oxygen concentrations are very low, but where predators are few and typical cephalopod food is scarce. PMID:23015627

  6. A Numerical Treatment of the Rf SQUID: II. Noise Temperature

    SciTech Connect

    Kleiner, Reinhold; Koelle, Dieter; Clarke, John

    2007-01-15

    We investigate rf SQUIDs (Superconducting QUantum Interference Devices), coupled to a resonant input circuit, a readout tank circuit and a preamplifier, by numerically solving the corresponding Langevin equations and optimizing model parameters with respect to noise temperature. We also give approximate analytic solutions for the noise temperature, which we reduce to parameters of the SQUID and the tank circuit in the absence of the input circuit. The analytic solutions agree with numerical simulations of the full circuit to within 10%, and are similar to expressions used to calculate the noise temperature of dc SQUIDs. The best device performance is obtained when {beta}{sub L}{prime} {triple_bond} 2{pi}LI{sub 0}/{Phi}{sub 0} is 0.6-0.8; L is the SQUID inductance, I{sub 0} the junction critical current and F{sub 0} the flux quantum. For a tuned input circuit we find an optimal noise temperature T{sub N,opt} {approx} 3Tf/f{sub c}, where T, f and f{sub c} denote temperature, signal frequency and junction characteristic frequency, respectively. This value is only a factor of 2 larger than the optimal noise temperatures obtained by approximate analytic theories carried out previously in the limit {beta}{sub L}{prime} << 1. We study the dependence of the noise temperature on various model parameters, and give examples using realistic device parameters of the extent to which the intrinsic noise temperature can be realized experimentally.

  7. A 128 Multiplexing Factor Time-Domain SQUID Multiplexer

    NASA Astrophysics Data System (ADS)

    Prêle, D.; Voisin, F.; Piat, M.; Decourcelle, T.; Perbost, C.; Chapron, C.; Rambaud, D.; Maestre, S.; Marty, W.; Montier, L.

    2016-01-01

    A cryogenic 128:1 Time-Domain Multiplexer (TDM) has been developed for the readout of kilo-pixel Transition Edge Sensor (TES) arrays dedicated to the Q&U Bolometric Interferometer for Cosmology (QUBIC) instrument which aims to measure the B-mode polarization of the Cosmic Microwave Background. Superconducting QUantum Interference Devices (SQUIDs) are usually used to read out TESs. Moreover, SQUIDs are used to build TDM by biasing sequentially the SQUIDs connected together—one for each TES. In addition to this common technique which allows a typical 32 multiplexing factor, a cryogenic integrated circuit provides a 4:1 second multiplexing stage. This cryogenic integrated circuit is one of the original part of our TDM achieving an unprecedented 128 multiplexing factor. We present these two dimension TDM stages: topology of the SQUID multiplexer, operation of the cryogenic integrated circuit, and integration of the full system to read out a TES array dedicated to the QUBIC instrument. Flux-locked loop operation in multiplexed mode is also discussed.

  8. A unique advantage for giant eyes in giant squid.

    PubMed

    Nilsson, Dan-Eric; Warrant, Eric J; Johnsen, Snke; Hanlon, Roger; Shashar, Nadav

    2012-04-24

    Giant and colossal deep-sea squid (Architeuthis and Mesonychoteuthis) have the largest eyes in the animal kingdom [1, 2], but there is no explanation for why they would need eyes that are nearly three times the diameter of those of any other extant animal. Here we develop a theory for visual detection in pelagic habitats, which predicts that such giant eyes are unlikely to evolve for detecting mates or prey at long distance but are instead uniquely suited for detecting very large predators, such as sperm whales. We also provide photographic documentation of an eyeball of about 27 cm with a 9 cm pupil in a giant squid, and we predict that, below 600 m depth, it would allow detection of sperm whales at distances exceeding 120 m. With this long range of vision, giant squid get an early warning of approaching sperm whales. Because the sonar range of sperm whales exceeds 120 m [3-5], we hypothesize that a well-prepared and powerful evasive response to hunting sperm whales may have driven the evolution of huge dimensions in both eyes and bodies of giant and colossal squid. Our theory also provides insights into the vision of Mesozoic ichthyosaurs with unusually large eyes. PMID:22425154

  9. High-Resolution Displacement Sensor Using a SQUID Array Amplifier

    NASA Technical Reports Server (NTRS)

    Chui, Talso; Penanen, Konstantin; Barmatz, M.; Paik, Ho Jung

    2004-01-01

    Improvement in the measurement of displacement has profound implications for both exploration technologies and fundamental physics. For planetary exploration, the new SQUID-based capacitive displacement sensor will enable a more sensitive gravity gradiometer for mapping the interior of planets and moons. A new concept of a superfluid clock to be reported by Penanen and Chui at this workshop is also based on a high-resolution displacement sensor. Examples of high-impact physics projects that can benefit from a better displacement sensor are: detection of gravitational waves, test of the equivalence principle, search for the postulated "axion" particle, and test of the inverse square law of gravity. We describe the concept of a new displacement sensor that makes use of a recent development in the Superconducting Quantum Interference Device (SQUID) technology. The SQUID array amplifier, invented by Welty and Martinis (IEEE Trans. Appl. Superconductivity 3, 2605, 1993), has about the same noise as a conventional SQUID; however, it can work at a much higher frequency of up to 5 MHz. We explain how the higher bandwidth can be translated into higher resolution using a bridge-balancing scheme that can simultaneously balance out both the carrier signal at the bridge output and the electrostatic force acting on the test mass.

  10. A YBCO RF-SQUID magnetometer and its applications

    NASA Technical Reports Server (NTRS)

    Luwei, Zhou; Jingwu, Qiu; Xienfeng, Zhang; Zhiming, Tank; Yongjia, Qian

    1990-01-01

    An applicable RF-superconducting quantum interference detector (SQUID) magnetometer was made using a bulk sintered yttrium barium copper oxide (YBCO). The temperature range of the magnetometer is 77 to 300 K and the field range 0 to 0.1T. At 77 K, the equivalent flux noise of the SQUID is 5 x 10 to minus 4 power theta sub o/square root of Hz at the frequency range of 20 to 200 Hz. The experiments show that the SQUID noise at low-frequency end is mainly from 1/f noise. A coil test shows that the magnetic moment sensitivity delta m is 10 to the minus 6th power emu. The RF-SQUID is shielded in a YBCO cylinder with a shielding ability B sub in/B sub ex of about 10 to the minus 6th power when external dc magnetic field is about a few Oe. The magnetometer is successfully used in characterizing superconducting thin films.

  11. Vampire squid: detritivores in the oxygen minimum zone.

    PubMed

    Hoving, Hendrik J T; Robison, Bruce H

    2012-11-22

    Vampire squid (Vampyroteuthis infernalis) are considered phylogenetic relics with cephalopod features of both octopods and squids. They lack feeding tentacles, but in addition to their eight arms, they have two retractile filaments, the exact functions of which have puzzled scientists for years. We present the results of investigations on the feeding ecology and behaviour of Vampyroteuthis, which include extensive in situ, deep-sea video recordings from MBARI's remotely operated vehicles (ROVs), laboratory feeding experiments, diet studies and morphological examinations of the retractile filaments, the arm suckers and cirri. Vampire squid were found to feed on detrital matter of various sizes, from small particles to larger marine aggregates. Ingested items included the remains of gelatinous zooplankton, discarded larvacean houses, crustacean remains, diatoms and faecal pellets. Both ROV observations and laboratory experiments led to the conclusion that vampire squid use their retractile filaments for the capture of food, supporting the hypothesis that the filaments are homologous to cephalopod arms. Vampyroteuthis' feeding behaviour is unlike any other cephalopod, and reveals a unique adaptation that allows these animals to spend most of their life at depths where oxygen concentrations are very low, but where predators are few and typical cephalopod food is scarce. PMID:23015627

  12. Crystallographic Study of the LUMI Intermediate of Squid Rhodopsin

    PubMed Central

    Murakami, Midori; Kouyama, Tsutomu

    2015-01-01

    Upon absorption of light, the retinal chromophore in rhodopsin isomerizes from the 11-cis to the trans configuration, initiating a photoreaction cycle. The primary photoreaction state, bathorhodopsin (BATHO), relaxes thermally through lumirhodopsin (LUMI) into a photoactive state, metarhodopsin (META), which stimulates the conjugated G-protein. Previous crystallographic studies of squid and bovine rhodopsins have shown that the structural change in the primary photoreaction of squid rhodopsin is considerably different from that observed in bovine rhodopsin. It would be expected that there is a fundamental difference in the subsequent thermal relaxation process between vertebrate and invertebrate rhodopsins. In this work, we performed crystallographic analyses of the LUMI state of squid rhodopsin using the P62 crystal. When the crystal was illuminated at 100 K with blue light, a half fraction of the protein was converted into BATHO. This reaction state relaxed into LUMI when the illuminated crystal was warmed in the dark to 170 K. It was found that, whereas trans retinal is largely twisted in BATHO, it takes on a more planar configuration in LUMI. This relaxation of retinal is accompanied by reorientation of the Schiff base NH bond, the hydrogen-bonding partner of which is switched to Asn185 in LUMI. Unlike bovine rhodopsin, the BATHO-to-LUMI transition in squid rhodopsin was accompanied by no significant change in the position/orientation of the beta-ionone ring of retinal. PMID:26024518

  13. SQUID-detected NMR and MRI in microtesla magnetic fields

    NASA Astrophysics Data System (ADS)

    McDermott, Robert Francis

    A low transition temperature do Superconducting QUantum Interference Device (low-Tc do SQUID) was used to perform liquid-state nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) experiments in magnetic fields from microtesla to tens of microtesla, corresponding to proton Larmor frequencies from tens of Hz to kHz. The spins were polarized in a magnetic field of the order of millitesla. Upon turnoff of the polarizing field, precession was induced in the much weaker measurement field. Because the SQUID magnetometer was operated with an untuned, superconducting, input circuit, the integrated intensity of the NMR lines was independent of the strength of the measurement field. On the other hand, the NMR linewidth scaled linearly with the measurement field strength. Narrowing of the NMR signal bandwidth through reduction of the strength of the measurement field led to an enhancement of both spectral resolution and signal-to-noise ratio (SNR). A novel cryogenic insert was constructed to allow SQUID measurement of NMR signals from room temperature samples with high filling factor. From samples with volume of a few milliliters and thermal polarization of order 10 -8, SNR of a few tens were achieved in a single shot. Heteronuclear scalar couplings were resolved in 1H-31P and 1H-13C systems. Furthermore, the frequency-independent sensitivity of the untuned SQUID magnetometer allowed simultaneous detection of NMR signals from nuclei with different magnetogyric ratios. A system based on a low-Tc SQUID gradiometer was used to acquire MRIs from distilled water and mineral oil phantoms in microtesla fields. The bandwidth-narrowing technique was exploited to enhance spatial resolution for a fixed strength of the encoding gradients. With magnetic field gradients of the order of tens of microtesla per meter, images with spatial resolution of a millimeter were achieved. The techniques described in this thesis could readily be adapted for use with multichannel SQUID systems designed for biomagnetic measurements at low frequency, and represent a first step toward the development of low cost, portable NMR and MRI scanners based on untuned SQUID magnetometers.

  14. Magnetic biosensor using a high transition temperature SQUID

    NASA Astrophysics Data System (ADS)

    Grossman, Helene Lila

    A high transition temperature (Tc) Superconducting QUantum Interference Device (SQUID) is used to detect magnetically-labeled microorganisms. The targets are identified and quantified by means of magnetic relaxation measurements, with no need for unbound magnetic labels to be washed away. The binding rate between antibody-linked magnetic particles and targets can be measured with this technique. Installed in a "SQUID microscope," a YBa2Cu 3O7-delta SQUID is mounted on a sapphire rod thermally linked to a liquid nitrogen can; these components are enclosed in a fiberglass vacuum chamber. A thin window separates the vacuum chamber from the sample, which is at room temperature and atmospheric pressure. In one mode of the experiment, targets are immobilized on a substrate and immersed a suspension of 50 nm diameter superparamagnetic particles, coated with antibodies. A pulsed magnetic field aligns the magnetic dipole moments, and the SQUID measures the magnetic relaxation signal each time the field is turned off. Unbound particles relax within 50 mus by Brownian rotation, too fast for the SQUID system to measure. In contrast, particles bound to targets have their Brownian motion inhibited. These particles relax in 1 s by rotation of the internal dipole moment, and this Neel relaxation process is detected by the SQUID. This assay is demonstrated with a model system of liposomes carrying the FLAG epitope; the detection limit is (2.7 +/- 0.2) x 105 particles. The replacement of the SQUID with a gradiometer improves the detection limit to (7.0 +/- 0.7) x 103 particles. In an alternate mode of the experiment, freely suspended targets (larger than 1 mum diameter) are detected. Since the Brownian relaxation time of the targets is longer than the measurement time, particles bound to targets are effectively immobilized and exhibit Neel relaxation. Listeria monocytogenes are detected using this method; the sensitivity is (1.1 +/- 0.2) x 105 bacteria in 20 muL. For a 1 nL sample volume, the detection limit is expected to be 230 +/- 40 bacteria. Time-resolved measurements, which yield the binding rate between particles and bacteria, are reported. Also, potential improvements to the system and possible applications are discussed.

  15. Paleointensity of the Martian field from SQUID Microscopy

    NASA Astrophysics Data System (ADS)

    Weiss, B. P.; Fong, L. E.; Lima, E. A.; Baudenbacher, F. J.; Vali, H.

    2005-12-01

    Crustal magnetic anomalies in the southern Martian hemisphere have intensities an order of magnitude larger than typical crustal anomalies on Earth. Two possible explanations for this difference are that compared to the present-day Earth, Mars has either (i) larger amounts of crustal ferromagnetic minerals or (ii) the crust was magnetized by a larger paleofield. ALH84001, the only pre-Amazonian Martian meteorite, possesses a stable magnetization dating to 4 Ga or earlier. Previous paleomagnetic studies with SQUID moment magnetometers on bulk ALH84001 grains have estimated that the paleointensity of the field which magnetized the meteorite was between 0.1-1 times that of the Earth's present field. However, these estimates may be lower limits on the true paleointensity because the orientation of the magnetization in ALH84001 is spatially heterogeneous on the submillimeter scale. This complication could have profound implications for hypothesis (ii) above. Here we first demonstrate that superconducting quantum interference device (SQUID) microscopy can recover the same magnetization intensity and direction of a well characterized modern-day terrestrial basalt as that measured with a 2G Enterprises SQUID moment magnetometer. A SQUID microscope paleointensity analysis of this basalt gives the expected present day field intensity of a few tens of microtesla. We further show that our new high resolution SQUID microscopy study of ALH84001, which has mapped its heterogeneous magnetization with the highest resolution yet (0.1 mm), favors the upper range of previous paleointensity estimates for the 4 Ga Martian paleofield (e.g., within a factor of several of that of the present-day Earth). However, this field, were it dynamo in origin, is still too weak to easily explain the intensity of the Martian magnetic anomalies.

  16. Cooling performance of hybrid refrigerant of solid nitrogen and small amount of neon for the purpose of HTS power applications

    NASA Astrophysics Data System (ADS)

    Higashikawa, K.; Nakamura, T.

    2009-11-01

    We have investigated cooling performance of a hybrid refrigerant of solid nitrogen and small amount of neon by using a short sample of Bi-2223/Ag tape as a cooling target. Solid nitrogen is expected as a heat capacitor for HTS applications operated below triple point temperature of nitrogen, and we have proposed in our previous study a method for overcoming the problem of its thermal contact with a cooling target with the aid of small amount of liquid neon. This paper discusses the phase state as well as the quantity of neon required for such an improvement. Nitrogen gas was introduced into a sample chamber through a mass flow controller, and then was liquefied and solidified by a Gifford-McMahon cryocooler. After that, in order to improve thermal contact of the solid nitrogen with the sample, neon gas was also introduced into the chamber at 25 K where neon can be liquefied. Cooling performance of such a hybrid refrigerant with different inputs of neon was evaluated by measuring temperature rise of the sample with the transportation of overcurrent. As a result, neon could suppress the temperature rise even in gas state, and the existence of liquid neon could additionally suppress the temperature rise. Furthermore, the required proportion of the liquid neon to the solid nitrogen was very small. From these results, we concluded that introducing neon until neon can be liquefied was the best way to make the most of the potential of the hybrid refrigerant.

  17. Predicting helium and neon adsorption and separation on carbon nanotubes by Monte Carlo simulation.

    PubMed

    Bolboli Nojini, Zabiollah; Abbas Rafati, Amir; Majid Hashemianzadeh, Seyed; Samiee, Sepideh

    2011-04-01

    The adsorption of helium and neon mixtures on single-walled carbon nanotubes (SWCNTs) was investigated at various temperatures (subcritical and supercritical) and pressures using canonical Monte Carlo (CMC) simulation. Adsorption isotherms were obtained at different temperatures (4, 40, 77 and 130 K) and pressures ranging from 1 to 16 MPa. Separation factors and isosteric enthalpies of adsorption were also calculated. Moreover, the adsorption isotherms were obtained at constant specific temperatures (4 and 40 K) and pressures (0.2 and 1.0 MPa) as a function of the amount adsorbed. All of the adsorption isotherms for an equimolar mixture of helium and neon have a Langmuir shape, indicating that no capillary condensation occurs. Both the helium and the neon adsorption isotherms exhibit similar behavior, and slightly more of the helium and neon mixture is adsorbed on the inner surfaces of the SWCNTs than on their outer surfaces. More neon is adsorbed than helium within the specified pressure range. The data obtained show that the isosteric enthalpies for the adsorption of neon are higher than those for helium under the same conditions, which means that adsorption of neon preferentially occurs by (15, 15) SWCNTs. Furthermore, the isosteric enthalpies of adsorption of both gases decrease with increasing temperature. PMID:20559855

  18. Triple-Point Temperature and the Isotopic Composition of Three Commercial Neon Gases

    NASA Astrophysics Data System (ADS)

    Yang, I.; Gam, K. S.; Joung, W.; Kim, Y.-G.

    2015-08-01

    The triple-point temperature of neon, , is known to have dependence on the isotopic composition. Recently, the Technical Annex for the International Temperature Scale of 1990 was updated to specify the method of correction for the isotopic reference ratio of neon. In this study, to confirm this correction in the Technical Annex independently, the effects of the isotopic composition of neon on for three commercial neon gas sources were studied. For the measurement of the isotopic composition, a gas mass spectrometer was used to compare the sample gases with a reference neon gas whose isotopic composition was known with high precision by a gravimetric method. For the measurement of , an open-cell type cryostat for the realization of low-temperature fixed points was used. The physical cell and the thermal environment around it remained very similar for all measurements with the neon gases due to the nature of the open-cell type system. Therefore, the difference in among different samples could be measured with a relatively low uncertainty, canceling many systematic effects that are common to all measurements. Our result was consistent with the correction in the Technical Annex. Furthermore, because one of the commercial neon gases was the bottle that was used for KRISS measurements in the international comparison CCT-K2, it is now possible to correct the measurement for the reference isotopic ratio and compare it with other measurements for which isotopic composition data are available.

  19. Mechanism of the tunable structural color of neon tetra

    NASA Astrophysics Data System (ADS)

    Yoshioka, Shinya

    2010-03-01

    Many examples of the structural color can be found in butterfly wings, beetle's elytra and bird feathers. Since the color-producing microstructures of these examples mainly consist of stable materials, for example, dried cuticles in insects and keratin and melanin granules in bird feathers, it is impossible to actively change the microstructure. On the other hand, some fish have the tunability in their structural colors. For example, a small tropical fish, neon tetra, has a longitudinal stripe that looks blue-green in the day time, while it changes into deep violet at night. This fact clearly indicates the variability in the microstructure. It is known that the iridophore of the stripe part of neon tetra contains two stacks of thin light-reflecting platelets that are made of guanine crystal. Since the arrangement of the platelets is observed periodic, the stack is thought to cause the structural color through the multilayer thin-film interference. Consequently, the variability in the color is thought to originate from the variation in the distance between the platelets. Two explanations have been proposed so far for the distance variation. Lythoge and Shand considered that the distance is controlled by osmotic pressure that induces the inflow of the water into the iridophore[1]. On the other hand, Nagaishi et al. proposed a different model, called Venetian blind model, in which the inclination angle of the platelets is varied, resulting in the change in the distance[2]. Recently, we have performed detailed optical measurements on the iridophore of neon tetra. We have paid particular attention to the direction of the reflected light, since the Venetian blind model expects that the direction varies with the color change owing to the tilt of the platelets. We present the experimental results and quantitatively discuss the validity of the Venetian blind model. [4pt] [1] J. N. Lythgoe, and J. Shand, J Physiol. 325, 23-34 (1982). [0pt] [2] H. Nagaishi, N. Oshima, and R. Fujii, Comp. Biochem. Physiol. 95A, 337-341 (1990).

  20. On the muon transfer from protium to neon

    NASA Astrophysics Data System (ADS)

    Romanov, S. V.

    2004-01-01

    The rate of the muon transfer from the 1S-state of muonic protium to neon is calculated in the interval of collision energies from 10-4 eV to 15 eV. The basic idea of the present treatment is to describe the entrance channel of the transfer reaction at large interatomic separations as correctly as possible. Accordingly, the three-body Hamiltonian is written in the Jacobi coordinates of the entrance channel, and a problem of the muon motion in the field of two fixed Coulomb centers is formulated in these coordinates. Its eigenstates are used as a basis in which the three-body wavefunction is expanded. Finally, the radial functions describing the relative motion in the entrance and transfer channels satisfy a set of coupled ordinary differential equations. Its solution allows one to find diagonal S-matrix elements corresponding to the entrance channel and, as a result, to obtain the total transfer cross-section and the amplitude of the elastic scattering. In this approach the description of the entrance channel proves to be free of the well-known defects -- incorrect dissociation limits and spurious long-range interactions. These defects are manifested only in the transfer channel. However, their effect seems to be not very significant because of large energies of the relative motion in this channel (a few keV). The calculation made here with four two-center ?-states taken into account reasonably reproduces the experimental transfer rate measured in liquid hydrogen-neon mixtures. The situation at room temperatures is worse: the theoretical value of the transfer rate exceeds the experimental one by a factor of two. However, the calculation clearly indicates the existence of a well pronounced minimum of the transfer rate at thermal energies. This result corresponds qualitatively to the experimental fact of a strong suppression of the muon transfer at room temperatures. At collision energies of 0.3-0.5 eV a resonant peak in the transfer rate is predicted. It is due to a quasi-steady state in the D-wave. The elastic scattering of muonic protium by neon is also treated. The effect of the electron screening in the entrance channel is studied in detail. It is found to be very significant right up to collision energies of 1-2 eV.

  1. Flying and Your Child's Ears

    MedlinePLUS

    ... All About Food Allergies Flying and Your Child's Ears KidsHealth > For Parents > Flying and Your Child's Ears ... a) cuando vuele en avión Flying's Effects on Ears Many of us have felt that weird ear- ...

  2. Flying and Your Child's Ears

    MedlinePLUS

    ... Caring for Your Child Flying and Your Child's Ears KidsHealth > For Parents > Flying and Your Child's Ears ... a) cuando vuele en avin Flying's Effects on Ears Many of us have felt that weird ear- ...

  3. Estimating Orientation of Flying Fruit Flies

    PubMed Central

    Cheng, Xi En; Wang, Shuo Hong; Qian, Zhi-Ming; Chen, Yan Qiu

    2015-01-01

    The recently growing interest in studying flight behaviours of fruit flies, Drosophila melanogaster, has highlighted the need for developing tools that acquire quantitative motion data. Despite recent advance of video tracking systems, acquiring a flying fly’s orientation remains a challenge for these tools. In this paper, we present a novel method for estimating individual flying fly’s orientation using image cues. Thanks to the line reconstruction algorithm in computer vision field, this work can thereby focus on the practical detail of implementation and evaluation of the orientation estimation algorithm. The orientation estimation algorithm can be incorporated into tracking algorithms. We rigorously evaluated the effectiveness and accuracy of the proposed algorithm by running experiments both on simulation data and on real-world data. This work complements methods for studying the fruit fly’s flight behaviours in a three-dimensional environment. PMID:26173128

  4. Use of activated charcoal for the purification of neon in the CLEAN experiment

    NASA Astrophysics Data System (ADS)

    Harrison, M. K.; Lippincott, W. H.; McKinsey, D. N.; Nikkel, J. A.

    2007-01-01

    Passage of neon gas through activated charcoal is planned to be the primary method of removing impurities from the liquid neon scintillator in the CLEAN experiment. In order to quantify this technique, the breakout curves for hydrogen, nitrogen, argon and krypton impurities in neon-saturated activated charcoal were measured. Adsorption coefficients and the number of theoretical stages were measured for hydrogen in the temperature range between 300 and 80 K, nitrogen between 300 and 200 K, and argon between 300 and 190 K. The adsorption coefficient for krypton was measured at 300 K.

  5. Influence of dust particles on ionization and excitation in neon dc discharge

    NASA Astrophysics Data System (ADS)

    Shumova, V. V.; Polyakov, D. N.; Vasilyak, L. M.

    2015-11-01

    The influence of dust particles on the concentration of metastable neon atoms and ionization was investigated using the developed drift/diffusion model for plasma of positive column of glow discharge. The detailed de-excitation in neon was considered. In addition to usual plasma losses in dusty plasmas, the quenching of metastable atoms on dust particle surface was considered. The strong influence of dust particles on the ionization rate and concentration of metastable neon atoms in a positive column of glow discharge is shown to result from the change in the longitudinal electric field strength.

  6. Dynamics of axial plasma jets in neon and argon plasma focus discharges

    NASA Astrophysics Data System (ADS)

    Baronova, E. O.; Vovchenko, E. D.; Maiorov, A. N.; Nikulin, V. Ya; Silin, P. V.; Stepanenko, A. M.; Suslin, S. V.; Vikhrev, V. V.

    2015-11-01

    Axial plasma jets at the final stage of plasma focus discharge filled by neon or argon were studied by the method of shearing interferometry. It was found that neon plasma is more stable than argon one and jets in neon are stronger than in argon. The velocity of current sheath, taken from experiment, is Vsh = (2-3) 106 cm/s, while the velocity of cumulative jet is Vj = (3-4) 107 cm/s. These features are supported by theoretical interpretation given in the frame of 2D MHD model.

  7. Ever Fly a Tetrahedron?

    ERIC Educational Resources Information Center

    King, Kenneth

    2004-01-01

    Few things capture the spirit of spring like flying a kite. Watching a kite dance and sail across a cloud spotted sky is not only a visually appealing experience it also provides a foundation for studies in science and mathematics. Put simply, a kite is an airfoil surface that flies when the forces of lift and thrust are greater than the forces of

  8. Ever Fly a Tetrahedron?

    ERIC Educational Resources Information Center

    King, Kenneth

    2004-01-01

    Few things capture the spirit of spring like flying a kite. Watching a kite dance and sail across a cloud spotted sky is not only a visually appealing experience it also provides a foundation for studies in science and mathematics. Put simply, a kite is an airfoil surface that flies when the forces of lift and thrust are greater than the forces of…

  9. Activation of fly ash

    DOEpatents

    Corbin, David R.; Velenyi, Louis J.; Pepera, Marc A.; Dolhyj, Serge R.

    1986-01-01

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  10. Activation of fly ash

    DOEpatents

    Corbin, D.R.; Velenyi, L.J.; Pepera, M.A.; Dolhyj, S.R.

    1986-08-19

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  11. Solid neon moderated electrostatic or magnetic positron beam

    SciTech Connect

    Weber, M.; Schwab, A.; Becker, D.; Lynn, K.G.

    1991-12-31

    A high intensity variable energy positron beam has been constructed at Brookhaven National Laboratory (BNL). Positrons from a 97mCi {sup 22}Na source are moderated by a thin layer of solid neon. A magnetic guiding system delivered up to 5{times}10{sup 6}e{sup +}/sec to an experiment. Currently tests are under way to facilitate the operation with the magnetic guiding system or -- for other experimental sites -- with an electrostatic beam transport. The electrostatic lenses are fabricated from {mu}-metal. No compensation of the earth magnetic field is required. Several experiments can utilize the beam on a time sharing basis. In the near future the source will be replaced by {sup 64}Cu which has a much higher activity. Beam intensities up to 10{sup 9}e{sup +}/sec are expected.

  12. Solid neon moderated electrostatic or magnetic positron beam

    SciTech Connect

    Weber, M.; Schwab, A. . Fakultaet fuer Physik); Becker, D.; Lynn, K.G. )

    1991-01-01

    A high intensity variable energy positron beam has been constructed at Brookhaven National Laboratory (BNL). Positrons from a 97mCi {sup 22}Na source are moderated by a thin layer of solid neon. A magnetic guiding system delivered up to 5{times}10{sup 6}e{sup +}/sec to an experiment. Currently tests are under way to facilitate the operation with the magnetic guiding system or -- for other experimental sites -- with an electrostatic beam transport. The electrostatic lenses are fabricated from {mu}-metal. No compensation of the earth magnetic field is required. Several experiments can utilize the beam on a time sharing basis. In the near future the source will be replaced by {sup 64}Cu which has a much higher activity. Beam intensities up to 10{sup 9}e{sup +}/sec are expected.

  13. Water depth measurement using an airborne pulsed neon laser system

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.; Frederick, E. B.

    1980-01-01

    The paper presents the water depth measurement using an airborne pulsed neon laser system. The results of initial base-line field test results of NASA airborne oceanographic lidar in the bathymetry mode are given, with water-truth measurements of depth and beam attenuation coefficients by boat taken at the same time as overflights to aid in determining the system's operational performance. The nadir-angle tests and field-of-view data are presented; this laser bathymetry system is an improvement over prior models in that (1) the surface-to-bottom pulse waveform is digitally recorded on magnetic tape, and (2) wide-swath mapping data may be routinely acquired using a 30 deg full-angle conical scanner.

  14. Helium and neon abundances and compositions in cometary matter.

    PubMed

    Marty, Bernard; Palma, Russell L; Pepin, Robert O; Zimmermann, Laurent; Schlutter, Dennis J; Burnard, Peter G; Westphal, Andrew J; Snead, Christopher J; Bajt, Sasa; Becker, Richard H; Simones, Jacob E

    2008-01-01

    Materials trapped and preserved in comets date from the earliest history of the solar system. Particles captured by the Stardust spacecraft from comet 81P/Wild 2 are indisputable cometary matter available for laboratory study. Here we report measurements of noble gases in Stardust material. Neon isotope ratios are within the range observed in "phase Q," a ubiquitous, primitive organic carrier of noble gases in meteorites. Helium displays 3He/4He ratios twice those in phase Q and in Jupiter's atmosphere. Abundances per gram are surprisingly large, suggesting implantation by ion irradiation. The gases are probably carried in high-temperature igneous grains similar to particles found in other Stardust studies. Collectively, the evidence points to gas acquisition in a hot, high ion-flux nebular environment close to the young Sun. PMID:18174437

  15. Helium and Neon Abundances and Compositions in Cometary Matter

    SciTech Connect

    Marty, B; Palma, R L; Pepin, R O; Zimmmermann, L; Schlutter, D J; Burnard, P G; Westphal, A J; Snead, C J; Bajt, S; Becker, R H; Simones, J E

    2007-10-15

    Materials trapped and preserved in comets date from the earliest history of the solar system. Particles captured by the Stardust spacecraft from comet Wild 2 are indisputable cometary matter available for laboratory study. Here they report measurements of noble gases in Stardust material. neon isotope ratios are within the range observed in 'phase Q', a ubiquitous, primitive organic carrier of noble gases in meteorites. Helium displays {sup 3}He/{sup 4}He ratios twice those in phase Q and in Jupiter's atmosphere. Abundances per gram are surprisingly large, suggesting implantation by ion irradiation. The gases are carried in high temperature igneous grains similar to particles found in other Stardust studies. Collectively the evidence points to gas acquisition in a hot, high ion flux nebular environment close to the young Sun.

  16. A Comparison of Detailed Level and Superconfiguration Models of Neon

    SciTech Connect

    Hansen, S B; Fournier, K B; Bauche-Arnoult, C; Bauche, J; Peyrusse, O

    2005-01-03

    The superconfiguration (SC) approach to collisional-radiative modeling can significantly decrease the computational demands of finding non-LTE level populations in complex systems. However, it has not yet been fully determined whether the statistical averaging of SC models leads to a significant loss of accuracy. The present work compares results from two independent models: a detailed-level accounting (DLA) model based on HULLAC data and the SC model MOST. The relatively simple level structures of the K- and L-shell ions of the neon test system ensure a tractable number of levels in the DLA model but challenge the statistical assumptions of the SC approach. Nonetheless, we find fair agreement between the two models for average ion charges, SC populations, and various effective temperatures.

  17. Neon as a Buffer Gas for a Mercury-Ion Clock

    NASA Technical Reports Server (NTRS)

    Prestage, John; Chung, Sang

    2008-01-01

    A developmental miniature mercury-ion clock has stability comparable to that of a hydrogen-maser clock. The ion-handling components are housed in a sealed vacuum tube, wherein a getter pump is used to maintain the partial vacuum, and the evacuated tube is backfilled with mercury vapor in a buffer gas. Neon was determined to be the best choice for the buffer gas: The pressure-induced frequency pulling by neon was found to be only about two-fifths of that of helium. Furthermore, because neon diffuses through solids much more slowly than does helium, the operational lifetime of a tube backfilled with neon could be considerably longer than that of a tube backfilled with helium.

  18. Equation of state of dense neon and krypton plasmas in the partial ionization regime

    NASA Astrophysics Data System (ADS)

    Chen, Q. F.; Zheng, J.; Gu, Y. J.; Li, Z. G.

    2015-12-01

    The compression behaviors of dense neon and krypton plasmas over a wide pressure-temperature range are investigated by self-consistent fluid variational theory. The ionization degree and equation of state of dense neon and krypton are calculated in the density-temperature range of 0.01-10 g/cm3 and 4-50 kK. A region of thermodynamic instability is found which is related to the plasma phase transition. The calculated shock adiabat and principal Hugoniot of liquid krypton are in good agreement with available experimental data. The predicted results of shock-compressed liquid neon are presented, which provide a guide for dynamical experiments or numerical first-principle calculations aimed at studying the compression properties of liquid neon in the partial ionization regime.

  19. Fragmentation dynamics of ionized neon trimer inside helium nanodroplets: a theoretical study.

    PubMed

    Bonhommeau, David; Viel, Alexandra; Halberstadt, Nadine

    2004-06-22

    We report a theoretical study of the fragmentation dynamics of Ne(3) (+) inside helium nanodroplets, following vertical ionization of the neutral neon trimer. The motion of the neon atoms is treated classically, while transitions between the electronic states of the ionic cluster are treated quantum mechanically. A diatomics-in-molecules description of the potential energy surfaces is used, in a minimal basis set consisting of three effective p orbitals on each neon atom for the missing electron. The helium environment is modeled by a friction force acting on the neon atoms when their speed exceeds the Landau velocity. A reasonable range of values for the corresponding friction coefficient is obtained by comparison with existing experimental measurements. PMID:15268166

  20. Establishment of 37 channel SQUID system for magnetocardiography

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    We report the development of a thirty seven channel SQUID based Magnetocardiography (MCG) system for the measurement of biomagnetic fields originating from the human heart. These fields are extremely weak and can be non-invasively measured only by using SQUID sensors. The system can simultaneously record biomagnetic signals at thirty seven spatial locations on the chest with a total coverage area of 300 cm2. The typical noise level of the system is measured to be about 2.5 fTrms/cm/√Hz for most gradiometer channels and around 7.3 fTrms/√Hz for magnetometer channels. The measurement of Magnetocardiogram (MCG) from human heart carried out using this system is shown.

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

    PubMed

    Schnau, T; Zakosarenko, V; Schmelz, M; Stolz, R; Anders, S; Linzen, S; Meyer, M; Meyer, H-G

    2015-10-01

    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(1/2). The width of superconducting strip lines is restricted to less than 6 ?m 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 ?T amplitude without the need for recalibration. PMID:26520976

  2. Energetics of an rf SQUID Coupled to Two Thermal Reservoirs

    PubMed Central

    Gardas, B.; Łuczka, J.; Ptok, A.; Dajka, J.

    2015-01-01

    We study energetics of a Josephson tunnel junction connecting a superconducting loop pierced by an external magnetic flux (an rf SQUID) and coupled to two independent thermal reservoirs of different temperature. In the framework of the theory of quantum dissipative systems, we analyze energy currents in stationary states. The stationary energy flow can be periodically modulated by the external magnetic flux exemplifying the rf SQUID as a quantum heat interferometer. We also consider the transient regime and identify three distinct regimes: monotonic decay, damped oscillations and pulse-type behavior of energy currents. The first two regimes can be controlled by the external magnetic flux while the last regime is robust against its variation. PMID:26641890

  3. Candidate Source of Flux Noise in SQUIDs: Adsorbed Oxygen Molecules

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Shi, Chuntai; Hu, Jun; Han, Sungho; Yu, Clare C.; Wu, R. Q.

    2015-08-01

    A major obstacle to using superconducting quantum interference devices (SQUIDs) as qubits is flux noise. We propose that the heretofore mysterious spins producing flux noise could be O2 molecules adsorbed on the surface. Using density functional theory calculations, we find that an O2 molecule adsorbed on an α-alumina surface has a magnetic moment of ˜1.8 μB . The spin is oriented perpendicular to the axis of the O-O bond, the barrier to spin rotations is about 10 mK. Monte Carlo simulations of ferromagnetically coupled, anisotropic X Y spins on a square lattice find 1 /f magnetization noise, consistent with flux noise in Al SQUIDs.

  4. TES Detector Noise Limited Readout Using SQUID Multiplexers

    NASA Technical Reports Server (NTRS)

    Staguhn, J. G.; Benford, D. J.; Chervenak, J. A.; Khan, S. A.; Moseley, S. H.; Shafer, R. A.; Deiker, S.; Grossman, E. N.; Hilton, G. C.; Irwin, K. D.

    2004-01-01

    The availability of superconducting Transition Edge Sensors (TES) with large numbers of individual detector pixels requires multiplexers for efficient readout. The use of multiplexers reduces the number of wires needed between the cryogenic electronics and the room temperature electronics and cuts the number of required cryogenic amplifiers. We are using an 8 channel SQUID multiplexer to read out one-dimensional TES arrays which are used for submillimeter astronomical observations. We present results from test measurements which show that the low noise level of the SQUID multiplexers allows accurate measurements of the TES Johnson noise, and that in operation, the readout noise is dominated by the detector noise. Multiplexers for large number of channels require a large bandwidth for the multiplexed readout signal. We discuss the resulting implications for the noise performance of these multiplexers which will be used for the readout of two dimensional TES arrays in next generation instruments.

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

    NASA Astrophysics Data System (ADS)

    Schönau, T.; Zakosarenko, V.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, M.; Meyer, H.-G.

    2015-10-01

    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/Hz1/2. 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.

  6. Energetics of an rf SQUID Coupled to Two Thermal Reservoirs

    DOE PAGESBeta

    Gardas, B.; Łuczka, J.; Ptok, A.; Dajka, J.

    2015-12-07

    We study energetics of a Josephson tunnel junction connecting a superconducting loop pierced by an external magnetic flux (an rf SQUID) and coupled to two independent thermal reservoirs of different temperature. In the framework of the theory of quantum dissipative systems, we analyze energy currents in stationary states. The stationary energy flow can be periodically modulated by the external magnetic flux exemplifying the rf SQUID as a quantum heat interferometer. Additionally, we consider the transient regime and identify three distinct regimes: monotonic decay, damped oscillations and pulse-type behavior of energy currents. Furthermore, the first two regimes can be controlled bymore » the external magnetic flux while the last regime is robust against its variation.« less

  7. Energetics of an rf SQUID Coupled to Two Thermal Reservoirs

    SciTech Connect

    Gardas, B.; Łuczka, J.; Ptok, A.; Dajka, J.

    2015-12-07

    We study energetics of a Josephson tunnel junction connecting a superconducting loop pierced by an external magnetic flux (an rf SQUID) and coupled to two independent thermal reservoirs of different temperature. In the framework of the theory of quantum dissipative systems, we analyze energy currents in stationary states. The stationary energy flow can be periodically modulated by the external magnetic flux exemplifying the rf SQUID as a quantum heat interferometer. Additionally, we consider the transient regime and identify three distinct regimes: monotonic decay, damped oscillations and pulse-type behavior of energy currents. Furthermore, the first two regimes can be controlled by the external magnetic flux while the last regime is robust against its variation.

  8. Detecting damage in steel with scanning SQUID microscopy

    SciTech Connect

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

    2001-09-04

    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.

  9. Electromagnetic Field Scattering on rf-SQUID Based Metasurfaces

    NASA Astrophysics Data System (ADS)

    Raputo, J. G.; Gabitov, I. R.; Kudyshev, Zh.; Kupaev, T.; Maimistov, A. I.

    2015-09-01

    Electromagnetic field scattering on a 2D array of rf-SQUIDs is considered. We show that the scattering changes for large amplitudes of the incident electromagnetic wave; above a critical amplitude, two different refraction states occur (bistability). In particular, for these two states, the transmitted wave polarization and angle of refraction are different. One could then switch the direction of propagation of the electromagnetic wave and its polarization with a "thin film", whose thickness is much smaller than the wavelength.

  10. Method and apparatus for cooling high temperature superconductors with neon-nitrogen mixtures

    DOEpatents

    Laverman, Royce J. (South Holland, IL); Lai, Ban-Yen (Hinsdale, IL)

    1993-01-01

    Apparatus and methods for cooling high temperature superconducting materials (HTSC) to superconductive temperatures within the range of 27.degree. K. to 77.degree. K. using a mixed refrigerant consisting of liquefied neon and nitrogen containing up to about ten mole percent neon by contacting and surrounding the HTSC material with the mixed refrigerant so that free convection or forced flow convection heat transfer can be effected.

  11. The origin of the neon isotopes in chondrites and on Earth

    NASA Astrophysics Data System (ADS)

    Moreira, Manuel; Charnoz, Sébastien

    2016-01-01

    We discuss the origin of the neon isotopic signatures in chondrites and in the terrestrial mantle. There are two primary possible origins for neon in the Earth's mantle. One origin is the dissolution of a dense primordial atmosphere with a solar composition of 20Ne/22Ne >13.4 into the mantle in a possible magma ocean stage during Earth's accretion. The second origin, developed in this study, is that mantle neon was already in Earth's parent bodies because of refractory grain irradiation by solar wind. We propose that solar wind implantation occurred early on dust within the accretion disk to allow such irradiation. Because solar wind implantation fractionates neon isotopes, the heavier isotopes are implanted deeper than the lighter ones because of different kinetic energies, and the process of implantation, if coupled with sputtering, leads to a steady state neon isotopic ratio (20Ne/22Ne ∼12.7) that is similar to what is observed in mantle-derived rocks (12.5-12.9), lunar soil grains (∼12.9) and certain gas-rich chondrites from all classes (enstatite, ordinary, rumuruti). Using a dust transport model in a turbulent and irradiated solar nebula, we estimated the equivalent irradiation age of a population of dust particles at three different distances from the sun (0.8, 1, 1.2 AU) and converted these ages into neon concentrations and isotopic ratios. The dust subsequently coagulated to form Earth's parent bodies, which have the mean neon isotopic composition of the irradiated dust (non-irradiated dust is assumed to be free of neon). If this scenario of solar wind implantation coupled with sputtering in the precursors of Earth's parent bodies is correct, it offers a simple alternative to the model of solar nebula gas incorporation by dissolution in a magma ocean.

  12. Emission anomalous optical magnetic resonances in a mixture of even neon isotopes

    SciTech Connect

    Saprykin, E. G.; Sorokin, V. A. Shalagin, A. M.

    2013-04-15

    Unusual resonances have been detected in the dependence of the discharge glow in neon on the longitudinal magnetic field. The resonances appear in fairly high magnetic fields and are observed only at low gas pressures and exclusively in a mixture of {sup 20}Ne and {sup 22}Ne isotopes. This phenomenon is an evidence of collective resonant radiation processes involving atoms of different neon isotopes.

  13. Laser optogalvanic wavelength calibration with a commercial hollow cathode iron - neon discharge lamp

    NASA Technical Reports Server (NTRS)

    Zhu, Xinming; Nur, Abdullahi H.; Misra, Prabhakar

    1994-01-01

    351 optogalvanic transitions have been observed in the 337 - 598 nm wavelength region using an iron - neon hollow cathode discharge lamp and a pulsed tunable dye laser. 223 of these have been identified as transitions associated with neon energy levels. These optogalvanic transitions have allowed, in conjunction with interference fringes recorded concomitantly with an etalon, the calibration of the dye laser wavelength with 0.3/cm accuracy.

  14. Fabrication and characterization of shunted μ-SQUID

    SciTech Connect

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Gupta, Anjan K.

    2014-04-24

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good I{sub c} vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function V{sub Φ} = 7.2mV/Φ{sub 0}. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  15. Tunable Anomalous Supercurrent in a topological tri-junction SQUID

    NASA Astrophysics Data System (ADS)

    Kurter, C.; Finck, A. D. K.; Ghaemi, P.; Hor, Y. S.; van Harlingen, D. J.

    2014-03-01

    There has been intense interest in realizing Majorana fermions (MFs) in solid-state systems. Circuits of Josephson junctions (JJs) made of closely spaced s-wave superconductors on 3D topological insulators have been proposed to host zero energy Andreev bound states (ABSs) that act like MFs. Here, we present signatures of an anomalous supercurrent carried by topologically non-trivial low energy ABSs in a Nb/Bi2Se3/Nb tri-junction SQUID where two of the three superconducting leads are connected by a loop. An electrostatic top gate allows strong modulation of the supercurrent despite a high bulk contribution to the normal state conductance. In response to a magnetic field threading flux within the superconducting loop, we find unconventional SQUID oscillations enclosed by an envelope associated with a clear diffraction pattern, indicating spatially uniform and symmetric JJs. At a critical gate voltage, when the trivial 2DEG at the surface is nearly depleted, we observe a sharp drop in the critical current, signaling a topological phase transition in which the nature of the supercurrent-carrying states is transformed. This transition is accompanied by qualitative changes in the SQUID oscillations, magnetic diffraction pattern, and temperature dependence of the critical current. We acknowledge funding from Microsoft Station-Q.

  16. Hierarchical, Self-Similar Structure in Native Squid Pen

    NASA Astrophysics Data System (ADS)

    Yang, Fei-Chi; Peters, Robert; Dies, Hannah; Rheinstadter, Maikel

    2014-03-01

    Proteins, chitin and keratin form the elementary building blocks of many biomaterials. How these molecules assemble into larger, macroscopic structures with very different properties is the fundamental question we are trying to answer. Squid pen is a transparent backbone inside the squid, which supports the mantle of the squid. The pens show a hierarchical, self-similar structure under the microscope and the AFM with fibers from 500 μm to 0.2 μm in diameter. The chitin molecules form nano-crystallites of monoclinic lattice symmetry surrounded by a protein layer, resulting in β-chitin nano-fibrils. Signals corresponding to the α-coil protein phase and β-chitin were observed in X-ray experiments in-situ. The molecular structure is highly anisotropic with 90% of the α-coils and β-chitin crystallites oriented along the fiber-axis indicating a strong correlation between the structures on millimeters down to the molecular scale. This research was funded by NSERC, NRC, CFI, and the Ontario Ministry of Economic Development and Innovation.

  17. Thermoelectric SQUID method for the detection of segregations

    NASA Astrophysics Data System (ADS)

    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.

  18. Ultra-low field SQUID magnetic resonance for biomedical research

    NASA Astrophysics Data System (ADS)

    Bhupathi, P.; Hahn, I.

    2014-03-01

    We are developing a SQUID (Superconducting QUantum Interference Device)-magnetometer system operating at 4K, for electron paramagnetic resonance (EPR) detection from room temperature samples in magnetic fields of the order of a Gauss. The magnetometer consists of a home-built, a second order gradiometer pick-up coil inductively coupled to the input of a commercially available two-stage dc SQUID amplifier with high bandwidth suitable for EPR, as well as NMR detection at wide range of frequencies up to a few MHz. Preliminary tests were done on samples of Pt powder at 4K and NMR signals have been detected in fields of few tens of gauss, with a minimum system sensitivity for spin concentration of ~1017. We are currently developing an optimal SQUID gradiometer and a low temperature dewar for the EPR measurements. We plan to operate at low EPR excitation frequencies of a few MHz with the advantages of negligible sample heating and high penetration depth in biological systems. We discuss the prospects for in vivo biomedical EPR imaging.

  19. Image and sample geometry effects in SQUID magnetometers

    NASA Astrophysics Data System (ADS)

    Zie̢ba, Andrzej

    1993-12-01

    This review concerns the interpretation of the signal provided by SQUID magnetometers designed for measurements of magnetization and magnetic susceptibility. ``Image effect'' refers to the influence of superconducting elements in the vicinity of the sample and detection coil. Several exact and approximate methods are presented for calculation of how the device sensitivity G(r) varies with position r of a unit dipole sample in the presence of a superconducting shielding tube. In particular, the relative decrease of G(r) is approximately given by the third power of the ratio of the detection coil and shield diameters, and the effect of the shield's finite length is found to be negligible in practical situations. A survey of complex detection coils (Helmholtz, saddle-type, gradiometer, and second derivative coil) includes calculation of the optimum spacing of the Helmholtz pair in the presence of a superconducting cylinder. The image effects due to the properties of the SQUID circuit and the field-dependent effects in high-field SQUID magnetometers are also discussed. Change in the instrument calibration due to sample size, shape, and location is considered for arbitrary samples as well as for specific cases of small, medium, and very long samples. A spherical harmonic expansion of G(r) makes it possible to derive simple formulas describing sample geometry effects for medium-sized samples with regular geometries (thin rod, cylinder, and rectangular parallelepiped). The results are compared to published experimental data.

  20. Design and applications of a scanning SQUID microscope

    SciTech Connect

    Kirtley, J.R.; Ketchen, M.B.; Tsuei, C.C.; Sun, J.Z.; Gallagher, W.J.; Yu-Jahnes, L.S.; Gupta, A.; Stawiasz, K.G.; Wind, S.J.

    1995-11-01

    The scanning SQUID (Superconducting Quantum Interference Device) microscope is an extremely sensitive instrument for imaging local magnetic fields. The authors describe one such instrument which combines a novel pivoting lever mechanism for coarse-scale imaging with a piezoelectric tube scanner for fine-scale scans. The magnetic field sensor is an integrated miniature SQUID magnetometer. This instrument has a demonstrated magnetic field sensitivity of <10{sup {minus}6} gauss/{radical}Hz at a spatial resolution of {approximately}10 {micro}m. The design and operation of this scanning SQUID microscope are described, and several illustrations of the capabilities of this technique are presented. The absolute calibration of this instrument with an ideal point source, a single vortex trapped in a superconducting film, is shown. The use of this instrument for the first observation of half-integer flux quanta, in tricrystal thin-film rings of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}, is described. The half-integer flux quantum effect is a general test of the symmetry of the superconducting order parameter. One such test rules out symmetry-independent mechanisms for the half-integer flux quantum effect, and proves that the order parameter in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} has lobes and nodes consistent with d-wave symmetry.

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

    SciTech Connect

    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.

  2. Transparency and coherence in rf SQUID metamaterials (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Anlage, Steven M.

    2015-09-01

    We have developed active metamaterials based on macroscopic quantum effects capable of quickly tuning their electrical and magnetic responses over a wide frequency range. These metamaterials are based on superconducting elements to form low insertion loss, physically and electrically small, highly tunable structures for the next generation rf electronics. The meta-atoms are rf superconducting quantum interference devices (SQUIDs) that incorporate the Josephson effect. RF SQUIDs have an inductance which includes a contribution from the Josephson inductance of the junction. This inductance is strongly tunable with dc and rf magnetic fields and currents. The rf SQUID metamaterial is a richly nonlinear effective medium introducing qualitatively new macroscopic quantum phenomena into the metamaterials community, namely magnetic flux quantization and the Josephson effect. The coherence of the metamaterials is strongly sensitive to the environment and measurement conditions. The metamaterials also display a unique form of transparency whose development can be manipulated through multiple parametric dependences. Further features such as breathers, superradiance, and self-induced transparency, along with entry into the fully quantum limit, will yield qualitatively new metamaterial phenomena. This work is supported by the NSF-GOALI and OISE Programs through Grant No. ECCS-1158644 and the Center for Nanophysics and Advanced Materials (CNAM).

  3. Apparatus for detecting a magnetic anomaly contiguous to remote location by squid gradiometer and magnetometer systems

    DOEpatents

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

    1984-01-01

    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.

  4. Development of a Neon Cryogenic Turbo-Expander with Magnetic Bearings

    NASA Astrophysics Data System (ADS)

    Hirai, H.; Hirokawa, M.; Yoshida, S.; Kamioka, Y.; Takaike, A.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

    2010-04-01

    A cryogenic turbo-expander with active magnetic bearings was made and tested in a reverse-Brayton cycle refrigerator using neon as working fluid. Turbine isentropic efficiency is a very important factor for the refrigerator since it affects the performance of the refrigerator significantly. Properties of neon are suitable for the working fluid in a refrigerator to cool HTS (High Temperature Superconducting) applications. The neon refrigerator needs a very small and high speed turbo-expander. But there are few studies of isentropic efficiencies of cryogenic turbo-expander using neon gas. Thus the experiment to get the design information was carried out. A prototype of neon refrigerator was made for HTS applications in 2007. Its cooling power was 2 kW at temperature of 70 K and operated in process pressure between 2 MPa and 1 MPa. To improve the performance of the neon refrigerator, the process pressure was changed to 1 MPa0.5 MPa. Under this process pressure, isentropic efficiencies for two types of turbine impellers were obtained. The test results were included in to the turbine design program so that we could predict the isentropic efficiencies of the turbo-expander more accurately. Details of the turbo-expander design and test results are described in this report.

  5. Contribution to the study of neon-nitrogen mixtures at low temperatures

    NASA Astrophysics Data System (ADS)

    Borges de Sousa, P.; Bonfait, G.

    2015-12-01

    Theoretical studies show that neon can influence the phase diagram of nitrogen, lowering its triple-point temperature. The use of a neon-nitrogen mixture that could remain liquid at temperatures below the triple-point of nitrogen (63.15 K) could solve some problems in the temperature range from 44 to 54 K, where no pure cryogenic liquids exist at all. This work consists of a preliminary study of mixtures of neon and nitrogen at low temperatures, in order to assess whether a liquid neon-nitrogen mixture below 63.15 K can be obtained. Indications that there may be a process of neon dilution in solid and liquid nitrogen are shown, as well as evidence of changes in the phase diagram of nitrogen due to the introduction of neon, in comparison to a model that supposes no interaction between the two substances. Evidences of a change in the nitrogen triple-point temperature from 63.15 to 62.5 K are presented and discussed.

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

    NASA Astrophysics Data System (ADS)

    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. SQUID detected NMR and NQR. Superconducting Quantum Interference Device.

    PubMed

    Augustine, M P; TonThat, D M; Clarke, J

    1998-03-01

    The dc Superconducting QUantum Interference Device (SQUID) is a sensitive detector of magnetic flux, with a typical flux noise of the order 1 muphi0 Hz(-1/2) at liquid helium temperatures. Here phi0 = h/2e is the flux quantum. In our NMR or NQR spectrometer, a niobium wire coil wrapped around the sample is coupled to a thin film superconducting coil deposited on the SQUID to form a flux transformer. With this untuned input circuit the SQUID measures the flux, rather than the rate of change of flux, and thus retains its high sensitivity down to arbitrarily low frequencies. This feature is exploited in a cw spectrometer that monitors the change in the static magnetization of a sample induced by radio frequency irradiation. Examples of this technique are the detection of NQR in 27Al in sapphire and 11B in boron nitride, and a level crossing technique to enhance the signal of 14N in peptides. Research is now focused on a SQUID-based spectrometer for pulsed NQR and NMR, which has a bandwidth of 0-5 MHz. This spectrometer is used with spin-echo techniques to measure the NQR longitudinal and transverse relaxation times of 14N in NH4ClO4, 63+/-6 ms and 22+/-2 ms, respectively. With the aid of two-frequency pulses to excite the 359 kHz and 714 kHz resonances in ruby simultaneously, it is possible to obtain a two-dimensional NQR spectrum. As a third example, the pulsed spectrometer is used to study NMR spectrum of 129Xe after polariza-tion with optically pumped Rb. The NMR line can be detected at frequencies as low as 200 Hz. At fields below about 2 mT the longitudinal relaxation time saturates at about 2000 s. Two recent experiments in other laboratories have extended these pulsed NMR techniques to higher temperatures and smaller samples. In the first, images were obtained of mineral oil floating on water at room temperature. In the second, a SQUID configured as a thin film gradiometer was used to detect NMR in a 50 microm particle of 195Pt at 6 mT and 4.2 K. PMID:9650797

  8. Hydrodynamic fin function of brief squid, Lolliguncula brevis.

    PubMed

    Stewart, William J; Bartol, Ian K; Krueger, Paul S

    2010-06-15

    Although the pulsed jet is often considered the foundation of a squid's locomotive system, the lateral fins also probably play an important role in swimming, potentially providing thrust, lift and dynamic stability as needed. Fin morphology and movement vary greatly among squid species, but the locomotive role of the fins is not well understood. To begin to elucidate the locomotive role of the fins in squids, fin hydrodynamics were studied in the brief squid Lolliguncula brevis, a species that exhibits a wide range of fin movements depending on swimming speed. Individual squid were trained to swim in both the arms-first and tail-first orientations against currents in a water tunnel seeded with light-reflective particles. Particle-laden water around the fins was illuminated with lasers and videotaped so that flow dynamics around the fins could be analyzed using digital particle image velocimetry (DPIV). Time-averaged forces generated by the fin were quantified from vorticity fields of the fin wake. During the low swimming speeds considered in this study [<2.5 dorsal mantle lengths (DML) per second], L. brevis exhibited four unique fin wake patterns, each with distinctive vortical structures: (1) fin mode I, in which one vortex is shed with each downstroke, generally occurring at low speeds; (2) fin mode II, an undulatory mode in which a continuous linked chain of vortices is produced; (3) fin mode III, in which one vortex is shed with each downstroke and upstroke, and; (4) fin mode IV, in which a discontinuous chain of linked double vortex structures is produced. All modes were detected during tail-first swimming but only fin modes II and III were observed during arms-first swimming. The fins produced horizontal and vertical forces of varying degrees depending on stroke phase, swimming speed, and swimming orientation. During tail-first swimming, the fins functioned primarily as stabilizers at low speeds before shifting to propulsors as speed increased, all while generating net lift. During arms-first swimming, the fins primarily provided lift with thrust production playing a reduced role. These results demonstrate the lateral fins are an integral component of the complex locomotive system of L. brevis, producing lift and thrust forces through different locomotive modes. PMID:20511514

  9. Helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure: A superior option

    PubMed Central

    XU, QI-HUA; ZHAO, CHEN; ZHU, JIAN-GANG; CHEN, MEI-JUAN; LIU, QING-HUAI

    2015-01-01

    The aim of the present study was to evaluate the efficacy of helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure and compare the results with those of a combined drugs and surgery regimen. A total of 70 patients with hydroxyapatite orbital implant exposure in 70 eyes were randomly divided into two groups: Helium-neon laser therapy (group A) and drugs plus surgery (group B). Each group contained 35 patients. The healing rates and times of the conjunctival wound were recorded and compared following helium-neon laser treatment or the drugs plus surgery regimen. Changes in the hydroxyapatite orbital implant prior to and following helium-neon laser irradiation were analyzed. A similar animal study was conducted using 24 New Zealand white rabbits, which received orbital implants and were then received drug treatment or helium-neon therapy. In the human experiment, the rates for conjunctival wound healing were 97.14% in group A and 74.29% in group B, with a significant difference between the groups (?2=5.71, P<0.05). Patients with mild exposure were healed after 7.222.11 days of helium-neon laser therapy and 14.333.20 days of drugs plus surgery. A statistically significant difference was found between the groups (t=8.97, P<0.05). Patients with moderate to severe exposure were healed after 18.192.12 days of helium-neon laser therapy and 31.254.21 days of drugs plus surgery. The difference between the groups was statistically significant (t=7.91, P<0.05). Enhanced magnetic resonance imaging showed that the helium-neon laser therapy significantly promoted vascularization of the hydroxyapatite orbital implant. These results, combined with pathological findings in animals, which showed that a helium-neon laser promoted vascularization and had anti-inflammatory effects, suggest that helium-neon laser irradiation is an effective method for treating hydroxyapatite orbital implant exposure, thereby avoiding secondary surgery. PMID:26622442

  10. Strange particle production in neutrino-neon charged current interactions

    SciTech Connect

    Plano, R.; Baker, N.J.; Connolly, P.L.; Kahn, S.A.; Murtagh, M.J.; Palmer, R.B.; Samios, N.P.; Tanaka, M.; Baltay, C.; Bregman, M.

    1986-01-01

    Neutral strange particle production in charged-current muon-neutrino interactions have been studied in the Fermilab 15-foot neon bubble chamber. Associated production is expected to be the major source of strange particles in charged-current neutrino interactions. sigma-neutral and xi-minus production by neutrinos was observed. The dependence on various leptonic and hadronic variables is investigated. A fit to single and associated production of s, s/anti-s, and c quarks is described based on the number of single and double strange particle production events. Inclusive neutral strange particle decays (V/sup 0/) production rates as a fraction of all charged-current events are measured and are tabulated. The lambda/K ratio is found to be 0.39 +- 0.04 and the fraction of lambda coming from sigma-neutral is (16 +- 5)%. The single- and double V/sup 0/ production was used to determine the associated s anti-s production rate and single s-quark production rate. 13 refs., 7 figs., 3 tabs. (LEW)

  11. Neon turbo-Brayton cycle refrigerator for HTS power machines

    NASA Astrophysics Data System (ADS)

    Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

    2012-06-01

    We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

  12. Effect of helium-neon laser on musculoskeletal trigger points

    SciTech Connect

    Snyder-Mackler, L.; Bork, C.; Bourbon, B.; Trumbore, D.

    1986-07-01

    Cold lasers have been proposed recently as a therapeutic tool for treating a wide variety of pathological conditions, including wounds, arthritis, orthopedic problems, and pain. These proposed therapeutic effects largely have been unsubstantiated by research. A randomized, double blind study was undertaken to ascertain the effect of a helium-neon (He-Ne) laser on the resistance of areas of skin overlying musculoskeletal trigger points. These areas usually demonstrate decreased skin resistance when compared with the surrounding tissue. Thirty patients with musculoskeletal trigger points were assigned randomly to either an experimental or a placebo group. In addition to standard physical therapy, each patient received three 15-second applications of a He-Ne laser or placebo stimulation from an identical unit that did not emit a laser. The results of a two-way analysis of covariance with one repeated measure showed a statistically significant increase (p less than .007) in skin resistance. This increase in an abnormal skin resistance pattern may accompany the resolution of pathological conditions.

  13. Metal atom (Zn, Cd and Mg) luminescence in solid neon

    NASA Astrophysics Data System (ADS)

    Healy, Brendan; Kerins, Paul; McCaffrey, John G.

    2012-08-01

    Luminescence spectroscopy of the metal atoms Mg, Zn and Cd isolated in solid neon is recorded using pulsed synchrotron radiation excitation of the ns1np1 1P1-ns2 1S0 resonance (n = 3, 4 and 5 respectively) transitions. Two features, a dominant band and a red-shoulder, are identified in the UV absorption spectra of Zn/Ne and Cd/Ne. Excitation of these features yields distinct emission bands with the red-shoulder absorption producing the smaller, Stokes-shifted emission. Nanosecond decaytime measurements, made with the time correlated single photon counting technique indicate the emission bands arise from the spin singlet 1P1?1S0 transition. Hence, it is concluded that the duplication of absorption and emission features in the Cd/Ne and Zn/Ne systems arises from metal atom occupancy in two distinct sites. In contrast, Mg/Ne luminescence consists of single excitation and emission bands, indicative of occupancy in just one site. The occurrence of distinct photophysical characteristics of the linewidths, Stokes shift and lifetimes in the Mg/Ne system, compared with those recorded for Zn/Ne and Cd/Ne, is rationalized in terms of a different site occupancy for atomic Mg. Accurate interaction potentials for the ground states of the M . Ne diatomics are used to analyse site occupancies and interpret this contrasting behavior.

  14. SQUID magnetometry from nanometer to centimeter length scales

    NASA Astrophysics Data System (ADS)

    Hatridge, Michael Jonathan

    Information stored in magnetic fields plays an important role in everyday life. This information exists over a remarkably wide range of sizes, so that magnetometry at a variety of length scales can extract useful information. Examples at centimeter to millimeter length scales include measurement of spatial and temporal character of fields generated in the human brain and heart, and active manipulation of spins in the human body for non-invasive magnetic resonance imaging (MRI). At micron length scales, magnetometry can be used to measure magnetic objects such as flux qubits; at nanometer length scales it can be used to study individual magnetic domains, and even individual spins. The development of Superconducting QUantum Interference Device (SQUID) based magnetometer for two such applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nanoscale magnetometry, are the focus of this thesis. Conventional MRI has developed into a powerful clinical tool for imaging the human body. This technique is based on nuclear magnetic resonance of protons with the addition application of three-dimensional magnetic field gradients to encode spatial information. Most clinical MRI systems involve magnetic fields generated by superconducting magnets, and the current trend is to higher magnetic fields than the widely used 1.5-T systems. Nonetheless, there is ongoing interest in the development of less expensive imagers operating at lower fields. The prepolarized, SQUID detected ultra-low field MRI (ULF MRI) developed by the Clarke group allows imaging in very weak fields (typically 132 muT, corresponding to a resonant frequency of 5.6 kHz). At these low field strengths, there is enhanced contrast in the longitudinal relaxation time of various tissue types, enabling imaging of objects which are not visible to conventional MRI, for instance prostate cancer. We are currently investigating the contrast between normal and cancerous prostate tissue in ex vivo prostate specimens in collaboration with the UCSF Genitourinary Oncology/Prostate SPORE Tissue Core. In characterizing pairs of nominally normal and cancerous tissue, we measure a marked difference in the longitudinal relaxation times, with an average value of cancerous tissue 0.66 times shorter than normal prostate tissue. However, in vivo imaging is required to definitively demonstrate the feasibility of ULF MR imaging of prostate cancer. To that end, we have worked to improve the performance of the system to facilitate human imaging. This is accomplished by increasing the prepolarizing field amplitude, and minimizing magnetic noise in the SQUID detector. We have achieved polarizing fields as high as 150 mT and SQUID effective field noise below 1 fT Hz-1/2, enabling us to demonstrate proof-of-principle in vivo images of the human forearm with 2 x 2 x 10 mm3 resolution in 6 minutes. On a much smaller spatial scale, there is currently fundamental and technological interest in measuring and manipulating nanoscale magnets, particularly in the quantum coherent regime. The observation of the dynamics of such systems requires a magnetometer with not only exceptional sensitivity but also high gain, wide bandwidth and low backaction. We demonstrate a dispersive magnetometer consisting of a two-junction SQUID in parallel with an integrated, lumped-element capacitor. Input flux signals are encoded as a phase modulation of the microwave drive tone applied to the magnetometer, resulting in a single quadrature voltage signal. For strong drive power, the nonlinearity of the resonator results in quantum limited, phase sensitive parametric amplification of this signal. We have achieved a bandwidth of 20 MHz---approximately two orders of magnitude higher than dispersive devices of comparable sensitivity---with an effective flux noise of 0.29 muphi0 Hz-12 . This performance is in excellent agreement with our theoretical model.

  15. 50 CFR 648.22 - Atlantic mackerel, squid, and butterfish specifications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... squid, which, subject to annual review, may be specified for a period of up to 3 years; (2) ACL; ACT... squid fishery for butterfish; which, subject to annual review, may be specified for a period of up to 3... review, may be specified for a period of up to 3 years. The Monitoring Committee may also recommend...

  16. 50 CFR 648.22 - Atlantic mackerel, squid, and butterfish specifications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... squid, which, subject to annual review, may be specified for a period of up to 3 years; (2) ACL; ACT... squid fishery for butterfish; which, subject to annual review, may be specified for a period of up to 3... review, may be specified for a period of up to 3 years. The Monitoring Committee may also recommend...

  17. 50 CFR 648.22 - Atlantic mackerel, squid, and butterfish specifications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... squid, which, subject to annual review, may be specified for a period of up to 3 years; (2) ACL; ACT... squid fishery for butterfish; which, subject to annual review, may be specified for a period of up to 3... review, may be specified for a period of up to 3 years. The Monitoring Committee may also recommend...

  18. Multiplexed Readout of MMC Detector Arrays Using Non-hysteretic rf-SQUIDs

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Wegner, M.; Gastaldo, L.; Fleischmann, A.; Enss, C.

    2014-08-01

    Metallic magnetic calorimeters (MMCs) are widely used for various experiments in fields ranging from atomic and nuclear physics to X-ray spectroscopy, laboratory astrophysics or material science. Whereas in previous experiments single pixel detectors or small arrays have been used, for future applications large arrays are needed. Therefore, suitable multiplexing techniques for MMC arrays are currently under development. A promising approach for the readout of large arrays is the microwave SQUID multiplexer that employs non-hysteretic rf-SQUIDs to create a frequency shift of high resonators that is in accordance with the detector signal and that can be monitored by using standard microwave measurement techniques. In this paper we discuss the design of a recently developed and fabricated 64 pixel detector array with integrated microwave SQUID multiplexer that was produced to test the suitability of this readout technique. The characterization of dc-SQUIDs with virtually identical washer design compared to the rf-SQUIDs of the SQUID multiplexer revealed that the crucial SQUID parameters such as the critical current of the Josephson junctions or the washer inductance are close to the design values and anticipates a successful operation of the SQUID multiplexer.

  19. 76 FR 66260 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... finalized regulations implementing the Omnibus Amendment (76 FR 60606, September 29, 2011), which... Service. For the reasons set out in the preamble, 50 CFR part 648, as amended at 76 FR 60649, September 29...), to allow the use of jigging gear to target longfin squid if the longfin squid fishery is closed...

  20. Ordinary SQUID interferometers and superfluid helium matter wave interferometers: The role of quantum fluctuations

    SciTech Connect

    Golovashkin, A. I.; Zherikhina, L. N. Tskhovrebov, A. M.; Izmailov, G. N.; Ozolin, V. V.

    2010-08-15

    When comparing the operation of a superfluid helium matter wave quantum interferometer (He SQUID) with that of an ordinary direct-current quantum interferometer (dc SQUID), we estimate their resolution limitation that correspond to quantum fluctuations. An alternative mode of operation of the interferometer as a unified macroquantum system is considered.

  1. 76 FR 74724 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-01

    ... November 7, 2011 (76 FR 68642). Details regarding the measures in Amendment 11 are in the final rule and... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Amendment 11 AGENCY: National Marine... implementing Amendment 11 to the Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan...

  2. 75 FR 32745 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-09

    ... meeting dates in a separate Federal Register notice published on May 27, 2010 (75 FR 29725). If the...; Atlantic Mackerel, Squid, and Butterfish Fisheries; Scoping Process AGENCY: National Marine Fisheries...) for Atlantic Mackerel, Squid, and Butterfish (MSB) and to prepare an EIS to analyze the impacts of...

  3. 76 FR 51272 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... Loligo was set at 3,384 mt (76 FR 8306, February 14, 2011). Due to an under harvest of the Trimester 1... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the 2011 Trimester 2 Directed Loligo Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic...

  4. 77 FR 40527 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-10

    ... percent of the quota (8,888 mt) (77 FR 16472, March 21, 2012). Due to an underharvest of quota in... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the 2012 Trimester 2 Directed Longfin Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic...

  5. 77 FR 58507 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-21

    ...-9135. SUPPLEMENTARY INFORMATION: Background Amendment 11 to the MSB FMP (76 FR 68642, November 7, 2011... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Framework Adjustment 5 AGENCY... Adjustment 5 to the Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan (MSB FMP), which...

  6. 77 FR 23635 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-20

    ..., 2011 (77 FR 16472). This action established catch levels for the 2012 fishing year for mackerel and... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management Measures... regulatory text in the final rule for 2012 Specifications for the Atlantic Mackerel, Squid, and...

  7. 75 FR 37739 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ... Butterfish Fisheries in the Federal Register on February 3, 2010 (75 FR 5537). The final rule modified... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Adjustment to the Loligo Trimester 2... Fishing Year (FY) Trimester 2 and 3 Loligo squid quotas. This action complies with the 2010...

  8. 75 FR 51683 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-23

    ... FR 5537, February 3, 2010). Section 648.22 requires NMFS to close the directed butterfish fishery in... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Directed Butterfish..., Squid, and Butterfish Fishery Management Plan (FMP). The procedures for setting the annual...

  9. 75 FR 1024 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-08

    ..., 2003 (68 FR 27516), NMFS published, at the request of the Council, an ANPR indicating that the Council... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Control Date for Loligo and Illex Squid AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric...

  10. A YBCO RF-squid variable temperature susceptometer and its applications

    NASA Technical Reports Server (NTRS)

    Zhou, Luwei; Qiu, Jinwu; Zhang, Xianfeng; Tang, Zhimin; Cai, Yimin; Qian, Yongjia

    1991-01-01

    The Superconducting QUantum Interference Device (SQUID) susceptibility using a high-temperature radio-frequency (rf) SQUID and a normal metal pick-up coil is employed in testing weak magnetization of the sample. The magnetic moment resolution of the device is 1 x 10(exp -6) emu, and that of the susceptibility is 5 x 10(exp -6) emu/cu cm.

  11. 76 FR 39313 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... butterfish is 495 mt (76 FR 8306, February 14, 2011). Section 648.22 requires NMFS to close the directed... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Directed... under the Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan (FMP). The procedures...

  12. Multiplexing of Hot-Electron Nanobolometers Using Microwave SQUIDs

    NASA Technical Reports Server (NTRS)

    Karasik, Boris S.; Day, Peter K.; Kawamura, Jonathan H.; Bumble, Bruce; LeDuc, Henry G.

    2009-01-01

    We have obtained the first data on the multiplexed operation of titanium hot-electron bolometers (HEB). Because of their low thermal conductance and small electron heat capacity nanobolometers are particularly interesting as sensors for far-infrared spectroscopy and mid- and near-IR calorimetry. However, the short time constant of these devices (approximately microseconds at 300-400 mK) makes time domain or audio-frequency domain multiplexing impractical. The Microwave SQUID (MSQUID) approach pursued in this work uses dc SQUIDs coupled to X-band microresonators which are, in turn, coupled to a transmission line. We used a 4-element array of Ti HEBs operated at 415 mK in a He3 dewar with an optical fiber access. The microwave signal exhibited 10-MHz wide resonances at individual MSQUD frequencies between 9 GHz and 10 GHz. The resonance depth is modulated by the current through the bolometer via a change of the SQUID flux state. The transmitted signal was amplified by a cryogenic amplifier and downconverted to baseband using an IQ mixer. A 1-dB per ??/2 responsivity was sufficient for keeping the system noise at the level of 2 pA/Hz1/2. This is more than an order of magnitude smaller than phonon noise in the HEB. The devices were able to detect single near- IR photons (1550 nm) with a time constant of 3.5 ?s. Follow-on work will scale the array to larger size and will address the microwave frequency signal generation and processing using a digital transceiver.

  13. DC SQUID detection of new magnetic resonance phenomena

    SciTech Connect

    Sleator, T.

    1986-01-01

    A dc Superconducting QUantum Interference Device (SQUID) was used as a tuned radio-frequency amplifier at liquid helium temperatures to detect very-low-signal magnetic resonance phenomena. Three experiments were performed. In the first experiment, a dc SQUID was used to detect pulsed nuclear quadrupole resonance at about 30 MHz. At a bath temperature of 4.2K, a total system noise temperature of 6 +/- 1K was achieved, with a quality factor Q of 2500. A novel Q-spoiler, consisting of a series array of Josephson tunnel junction, reduced the ring-down time of the tuned circuit after each pulse. The minimum number of nuclear Bohr magnetons observable from a free-precession signal after a single pulse was about 2 x 10/sup 16/ in a bandwidth of 10 kHz. In the second experiment, a sample of nuclear spins was placed in the inductor of a tuned LCR circuit and the spectral density of current fluctuations in the circuit was measured using a dc SQUID as an rf amplifier. The measurements were made in liquid helium at 1.5K on samples of NaClO/sub 3/ and KClO/sub 3/, each of which exhibit a /sup 35/Cl NQR transition at about 30 MHz. In the third experiment, precessing nuclear quadrupole moments were observed to induce oscillating electric dipole moments in neighboring atoms. The /sup 35/Cl nuclei of a single crystal of NaClO/sub 3/ placed between the plates of a capacitor were excited into precession by a rf pulse.

  14. Cephalopod coloration model. I. Squid chromatophores and iridophores.

    PubMed

    Sutherland, Richard L; Mthger, Lydia M; Hanlon, Roger T; Urbas, Augustine M; Stone, Morley O

    2008-03-01

    We have developed a mathematical model of skin coloration in cephalopods, a class of aquatic animals. Cephalopods utilize neurological and physiological control of various skin components to achieve active camouflage and communication. Specific physical processes of this coloration are identified and modeled, utilizing available biological materials data, to simulate active spectral changes in pigment-bearing organs and structural iridescent cells. Excellent agreement with in vitro measurements of squid skin is obtained. A detailed understanding of the physical principles underlying cephalopod coloration is expected to yield insights into the behavioral ecology of these animals. PMID:18311226

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  16. Issues relating to airborne applications of HTS SQUIDs

    NASA Astrophysics Data System (ADS)

    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.

    2002-12-01

    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.

  17. Optimum ion channel properties in the squid giant axon

    NASA Astrophysics Data System (ADS)

    Adair, Robert K.

    2004-04-01

    Evolutionary pressures are presumed to act so as to maximize the efficiency of biological systems. However, the utility of that premise is marred by the difficulties in defining and evaluating both the efficiency of systems and the character of the available variation space. Following Hodgkin and Adrian, we examine the character of voltage gated ion channels in the nonmyelinated giant axons of the squid and find that both the channel densities and channel transition rates have values that nearly optimize signal sensitivity as well as signal velocity.

  18. Technical and commerical challenges in high Tc SQUIDs and their industrial applications

    NASA Technical Reports Server (NTRS)

    Lu, D. F.

    1995-01-01

    A SQUID is the most sensitive device for measuring changes in magnetic flux. Since its discovery in the sixties, scientists have made consistent efforts to apply SQUID's to various applications. Instruments that are the most sensitive in their respective categories have been built, such as SQUID DC susceptometer that is now manufactured by Quantum Design, pico-voltmeter which could measure 10(exp -14) volts, and gravitational wave detectors. One of the most successful applications of SQUID's is in magnetoencephalography, a non-invasive technique for investigating neuronal activity in the living human brain. This technique employs a multi-channel SQUID magnetometer that maps the weak magnetic field generated by small current when information is processed in brain, and its performance is marvelous.

  19. Noise of dc-SQUIDs with planar sub-micrometer Nb/HfTi/Nb junctions

    NASA Astrophysics Data System (ADS)

    Beyer, J.; Klemm, M.; Storm, J. H.; Kieler, O.; Weimann, T.; Morosh, V.

    2015-08-01

    We have fabricated Nb-based dc-SQUIDs with sub-micrometer planar Nb/HfTi/Nb junctions in order to investigate their noise performance. The SQUIDs are of simple coplanar design, their nominal inductance is ca. 15 pH. Electron beam lithography and chemical-mechanical polishing have been used to realize junctions with cross sections areas as low as about 100 × 100 nm2. The SQUIDs exhibit pronounced excess noise increasing towards lower frequencies. This apparent flux noise arises from fluctuations of the junction critical currents or resistances. The Nb/HfTi/Nb junction critical currents are found to be strongly temperature dependent. Upon cooling below ca. 4 K the SQUIDs start to show current-voltage characteristics with negative differential resistances, and their flux noise increases significantly. Estimation of the HfTi barrier electron temperature indicates that the degradation of the SQUID properties towards lower temperature is caused by self-heating effects.

  20. The fabrication and characterization of nano-SQUIDs based on Nb thin films

    NASA Astrophysics Data System (ADS)

    Liu, Xixi; Liu, Xiaoyu; Wang, Hao; Chen, Lei; Wang, Zhen

    2015-08-01

    SQUIDs with nano-junctions (or nano-SQUIDs) are able to be miniaturized into nanoscale to measure a single Bohr magneton. Here, we reported the development of a fabrication process for Nb (niobium) nano-SQUIDs using the thin film deposition and the electron-beam lithography technology. The developed process started from a high-quality superconducting thin film so that it is compatible with a variety of film growing techniques. The as-fabricated nano-SQUIDs exhibited functional flux modulation depth up to 10.3% at 4.6 K, in agreement with the numerical simulation based on the Ginzburg-Landau equation. By further comparing the results from both experiments and simulations, we found that a small critical current below ∼50 μA played a leading role in order to obtain a decent flux-modulation depth for Nb nano-SQUIDs.

  1. Metallic Magnetic Calorimeters with On-Chip dc-SQUID Readout

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Ferring, A.; Fleischmann, A.; Wegner, M.; Enss, C.

    2015-09-01

    Metallic magnetic calorimeters (MMCs) are low-temperature particle detectors that are typically read out by using superconducting quantum interference devices (SQUIDs). But since MMCs are sensitive to the input circuitry and the noise performance of the SQUID, the energy resolution of MMCs have not yet reached their fundamental limit. A possible solution to overcome present limits is to maximize the flux coupling by minimizing parasitic inductance in the input circuit. To show the suitability of this approach, we realized a 64 pixel MMC detector array with integrated dc-SQUID readout, i.e., detector and SQUID are on the same chip. We observed an influence of the power dissipation of the SQUID on the detector temperature. We achieved a baseline energy resolution of Δ E_{FWHM} = 25 {eV} and Δ E_{FWHM} = 30 {eV} for X-rays with energies up to 6 {keV}.

  2. NEON Data Products: Supporting the Validation of GCOS Essential Climate Variables

    NASA Astrophysics Data System (ADS)

    Petroy, S. B.; Fox, A. M.; Metzger, S.; Thorpe, A.; Meier, C. L.

    2014-12-01

    The National Ecological Observatory Network (NEON) is a continental-scale ecological observation platform designed to collect and disseminate data that contributes to understanding and forecasting the impacts of climate change, land use change, and invasive species on ecology. NEON will collect in-situ and airborne data over 60 sites across the US, including Alaska, Hawaii, and Puerto Rico. The NEON Biomass, Productivity, and Biogeochemistry protocols currently direct the collection of samples from distributed, gradient, and tower plots at each site, with sampling occurring either multiple times during the growing season, annually, or on three- or five-year centers (e.g. for coarse woody debris). These data are processed into a series of field-derived data products (e.g. Biogeochemistry, LAI, above ground Biomass, etc.), and when combined with the NEON airborne hyperspectral and LiDAR imagery, are used support validation efforts of algorithms for deriving vegetation characteristics from the airborne data. Sites are further characterized using airborne data combined with in-situ tower measurements, to create additional data products of interest to the GCOS community, such as Albedo and fPAR. Presented here are a summary of tower/field/airborne sampling and observation protocols and examples of provisional datasets collected at NEON sites that may be used to support the ongoing validation of GCOS Essential Climate Variables.

  3. Effect of combined misonidazole and accelerated neon ions on a human melanoma transplanted into nude mice

    SciTech Connect

    Guichard, M.; Tenforde, T.; Curtis, S.; Malaise, E.P.

    1982-01-01

    The response to accelerated neon ions of human Nall melanomas growing in nude mice was measured by an in vitro colony-forming assay following in situ tumor irradiation in the midposition of a 10-cm extended-peak ionization region. Values of the relative biological effectiveness (RBE) for peak neon ions compared with 60Co gamma radiation were 3.2 and 3.4, respectively, at the 1% and 10% survival levels. Following irradiation with peak neon ions, the repair of potentially lethal damage (PLD) was comparable to that observed after gamma irradiation. When misonidazole (1 mg/g intraperitoneal dose) was administered in combination with extended-peak neon ions, the drug enhancement ratio (ER) at the 1% survival level was 1.5 if the tumors were removed and plated in vitro immediately following irradiation, and 1.9 if tumor excision and plating were delayed for greater than 6 hours. Administration of misonidazole completely inhibited PLD repair following either gamma irradiation or extended-peak neon-ion irradiation.

  4. Effect of combined misonidazole and accelerated neon ions on a human melanoma transplanted into nude mice

    SciTech Connect

    Guichard, M.; Tenforde, T.; Curtis, S.; Malaise, E.P.

    1982-01-01

    The response to accelerated neon ions of human Nall melanomas growing in nude mice was measured by an in vitro colony-forming assay following in situ tumor irradiation in the midposition of a 10-cm extended-peak ionization region. Values of the relative biological effectiveness (RBE) for peak neon ions compared with /sup 60/Co..gamma.. radiation were 3.2 and 3.4, respectively, at the 1% and 10% survival levels. Following irradiation with peak neon ions, the repair of potentially lethal damage (PLD) was comparable to that observed after ..gamma.. irradiation. When misonidazole (1 mg/g intraperitoneal dose) was administered in combination with extended-peak neon ions, the drug enhancement ratio (ER) at the 1% survival level was 1.5 if the tumors were removed and plated in vitro immediately following irradiation, and 1.9 if tumor excision and plating were delayed for greater than or equal to 6 hours. Administration of misonidazole completely inhibited PLD repair following either ..gamma.. irradiation or extended peak neon-ion irradiation.

  5. A strategy to sample nutrient dynamics across the terrestrial-aquatic interface at NEON sites

    NASA Astrophysics Data System (ADS)

    Hinckley, E. S.; Goodman, K. J.; Roehm, C. L.; Meier, C. L.; Luo, H.; Ayres, E.; Parnell, J.; Krause, K.; Fox, A. M.; SanClements, M.; Fitzgerald, M.; Barnett, D.; Loescher, H. W.; Schimel, D.

    2012-12-01

    The construction of the National Ecological Observatory Network (NEON) across the U.S. creates the opportunity for researchers to investigate biogeochemical transformations and transfers across ecosystems at local-to-continental scales. Here, we examine a subset of NEON sites where atmospheric, terrestrial, and aquatic observations will be collected for 30 years. These sites are located across a range of hydrological regimes, including flashy rain-driven, shallow sub-surface (perched, pipe-flow, etc), and deep groundwater, which likely affect the chemical forms and quantities of reactive elements that are retained and/or mobilized across landscapes. We present a novel spatial and temporal sampling design that enables researchers to evaluate long-term trends in carbon, nitrogen, and phosphorus biogeochemical cycles under these different hydrological regimes. This design focuses on inputs to the terrestrial system (atmospheric deposition, bulk precipitation), transfers (soil-water and groundwater sources/chemistry), and outputs (surface water, and evapotranspiration). We discuss both data that will be collected as part of the current NEON design, as well as how the research community can supplement the NEON design through collaborative efforts, such as providing additional datasets, including soil biogeochemical processes and trace gas emissions, and developing collaborative research networks. Current engagement with the research community working at the terrestrial-aquatic interface is critical to NEON's success as we begin construction, to ensure that high-quality, standardized and useful data are not only made available, but inspire further, cutting-edge research.

  6. Flies and the mouth.

    PubMed

    Hassona, Yazan; Scully, Crispian; Aguida, Miranda; de Almeida, Oslei Paes

    2014-05-01

    Oral infections caused by flies are rarely encountered in clinical practice, and consequently, there is a paucity of information in the medical and dental literature about these conditions. In the present article, we present a concise review on oral myiasis or fly-blown disease. A variety of fly species can infest the oral tissues and produce an exotic clinical picture. Oral myiasis is mainly encountered in the tropics and subtropics, but can also be encountered in the western part of the world due to the increase of globalization, immigration, and global warming. Commonly-reported symptoms of oral myiasis include pain, swelling, itchy sensation, and feeling of something moving in the mouth. The surgical debridement of infected tissue with the removal of maggots is the treatment of choice in most cases of oral myiasis. PMID:24574273

  7. Flies without centrioles.

    PubMed

    Basto, Renata; Lau, Joyce; Vinogradova, Tatiana; Gardiol, Alejandra; Woods, C Geoffrey; Khodjakov, Alexey; Raff, Jordan W

    2006-06-30

    Centrioles and centrosomes have an important role in animal cell organization, but it is uncertain to what extent they are essential for animal development. The Drosophila protein DSas-4 is related to the human microcephaly protein CenpJ and the C. elegans centriolar protein Sas-4. We show that DSas-4 is essential for centriole replication in flies. DSas-4 mutants start to lose centrioles during embryonic development, and, by third-instar larval stages, no centrioles or centrosomes are detectable. Mitotic spindle assembly is slow in mutant cells, and approximately 30% of the asymmetric divisions of larval neuroblasts are abnormal. Nevertheless, mutant flies develop with near normal timing into morphologically normal adults. These flies, however, have no cilia or flagella and die shortly after birth because their sensory neurons lack cilia. Thus, centrioles are essential for the formation of centrosomes, cilia, and flagella, but, remarkably, they are not essential for most aspects of Drosophila development. PMID:16814722

  8. Autonomous Flying Controls Testbed

    NASA Technical Reports Server (NTRS)

    Motter, Mark A.

    2005-01-01

    The Flying Controls Testbed (FLiC) is a relatively small and inexpensive unmanned aerial vehicle developed specifically to test highly experimental flight control approaches. The most recent version of the FLiC is configured with 16 independent aileron segments, supports the implementation of C-coded experimental controllers, and is capable of fully autonomous flight from takeoff roll to landing, including flight test maneuvers. The test vehicle is basically a modified Army target drone, AN/FQM-117B, developed as part of a collaboration between the Aviation Applied Technology Directorate (AATD) at Fort Eustis,Virginia and NASA Langley Research Center. Several vehicles have been constructed and collectively have flown over 600 successful test flights.

  9. Swimming mechanics and behavior of the shallow-water brief squid Lolliguncula brevis.

    PubMed

    Bartol, I K; Patterson, M R; Mann, R

    2001-11-01

    Although squid are among the most versatile swimmers and rely on a unique locomotor system, little is known about the swimming mechanics and behavior of most squid, especially those that swim at low speeds in inshore waters. Shallow-water brief squid Lolliguncula brevis, ranging in size from 1.8 to 8.9 cm in dorsal mantle length (DML), were placed in flumes and videotaped, and the data were analyzed using motion-analysis equipment. Flow visualization and force measurement experiments were also performed in water tunnels. Mean critical swimming speeds (U(crit)) ranged from 15.3 to 22.8 cm s(-1), and mean transition speeds (U(t); the speed above which squid swim exclusively in a tail-first orientation) varied from 9.0 to 15.3 cm s(-1). At low speeds, negatively buoyant brief squid generated lift and/or improved stability by positioning the mantle and arms at high angles of attack, directing high-speed jets downwards (angles >50 degrees ) and using fin activity. To reduce drag at high speeds, the squid decreased angles of attack and swam tail-first. Fin motion, which could not be characterized exclusively as drag- or lift-based propulsion, was used over 50-95 % of the sustained speed range and provided as much as 83.8 % of the vertical and 55.1 % of the horizontal thrust. Small squid (<3.0 cm DML) used different swimming strategies from those of larger squid, possibly to maximize thrust benefits from vortex ring formation. Furthermore, brief squid employed various unsteady behaviors, such as manipulating funnel diameter during jetting, altering arm position and swimming in different orientations, to boost swimming performance. These results demonstrate that locomotion in slow-swimming squid is complex, involving intricate spatial and temporal interactions between the mantle, fins, arms and funnel. PMID:11719531

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Type Ia supernovae from exploding oxygen-neon white dwarfs

    NASA Astrophysics Data System (ADS)

    Marquardt, Kai S.; Sim, Stuart A.; Ruiter, Ashley J.; Seitenzahl, Ivo R.; Ohlmann, Sebastian T.; Kromer, Markus; Pakmor, Rdiger; Rpke, Friedrich K.

    2015-08-01

    Context. The progenitor problem of Type Ia supernovae (SNe Ia) is still unsolved. Most of these events are thought to be explosions of carbon-oxygen (CO) white dwarfs (WDs), but for many of the explosion scenarios, particularly those involving the externally triggered detonation of a sub-Chandrasekhar mass WD (sub-MCh WD), there is also a possibility of having an oxygen-neon (ONe) WD as progenitor. Aims: We simulate detonations of ONe WDs and calculate synthetic observables from these models. The results are compared with detonations in CO WDs of similar mass and observational data of SNe Ia. Methods: We perform hydrodynamic explosion simulations of detonations in initially hydrostatic ONe WDs for a range of masses below the Chandrasekhar mass (MCh), followed by detailed nucleosynthetic postprocessing with a 384-isotope nuclear reaction network. The results are used to calculate synthetic spectra and light curves, which are then compared with observations of SNe Ia. We also perform binary evolution calculations to determine the number of SNe Ia involving ONe WDs relative to the number of other promising progenitor channels. Results: The ejecta structures of our simulated detonations in sub-MCh ONe WDs are similar to those from CO WDs. There are, however, small systematic deviations in the mass fractions and the ejecta velocities. These lead to spectral features that are systematically less blueshifted. Nevertheless, the synthetic observables of our ONe WD explosions are similar to those obtained from CO models. Conclusions: Our binary evolution calculations show that a significant fraction (3-10%) of potential progenitor systems should contain an ONe WD. The comparison of our ONe models with our CO models of comparable mass (~1.2 M?) shows that the less blueshifted spectral features fit the observations better, although they are too bright for normal SNe Ia.

  12. Assessing the trophic position and ecological role of squids in marine ecosystems by means of food-web models

    NASA Astrophysics Data System (ADS)

    Coll, Marta; Navarro, Joan; Olson, Robert J.; Christensen, Villy

    2013-10-01

    We synthesized available information from ecological models at local and regional scales to obtain a global picture of the trophic position and ecological role of squids in marine ecosystems. First, static food-web models were used to analyze basic ecological parameters and indicators of squids: biomass, production, consumption, trophic level, omnivory index, predation mortality diet, and the ecological role. In addition, we developed various dynamic temporal simulations using two food-web models that included squids in their parameterization, and we investigated potential impacts of fishing pressure and environmental conditions for squid populations and, consequently, for marine food webs. Our results showed that squids occupy a large range of trophic levels in marine food webs and show a large trophic width, reflecting the versatility in their feeding behaviors and dietary habits. Models illustrated that squids are abundant organisms in marine ecosystems, and have high growth and consumption rates, but these parameters are highly variable because squids are adapted to a large variety of environmental conditions. Results also show that squids can have a large trophic impact on other elements of the food web, and top-down control from squids to their prey can be high. In addition, some squid species are important prey of apical predators and may be keystone species in marine food webs. In fact, we found strong interrelationships between neritic squids and the populations of their prey and predators in coastal and shelf areas, while the role of squids in open ocean and upwelling ecosystems appeared more constrained to a bottom-up impact on their predators. Therefore, large removals of squids will likely have large-scale effects on marine ecosystems. In addition, simulations confirm that squids are able to benefit from a general increase in fishing pressure, mainly due to predation release, and quickly respond to changes triggered by the environment. Squids may thus be very sensitive to the effects of fishing and climate change.

  13. Structural health monitoring of materials by high critical temperature SQUID

    NASA Astrophysics Data System (ADS)

    Valentino, M.; Ruosi, A.; Peluso, G.; Pepe, G. P.

    2002-08-01

    Nowadays, tailoring the material properties is essential for advanced product design in engineering systems. The need to provide key information about micro- and macro-structural behaviour of materials, without destructively sectioning the sample, has spurred the development of nondestructive evaluation methodologies. These techniques are required during material production, quality testing of components during manufacturing, and in-service inspection of structural integrity. To ensure the highest possible operational safety along with an economic efficiency, it is necessary to carry out inspections with a high sensitivity and a proven reliability. Due to its unparalleled magnetic field sensitivity over a wide frequency range and large dynamic range, SQUID-based nondestructive evaluation has unique advantages for materials and structures characterization. We will present an overview of eddy-current nondestructive analysis utilizing high Tc SQUIDs with an emphasis on examples relevant to the aeronautical industry. These include the detection of deep-lying defects in multi-layer structures of Al-Ti alloys and damage of extremely lightweight graphite/epoxy composites. Both of these can be successfully treated by this approach where conventional electromagnetic probes often fail. In addition some results based on the volume integral formulation, successfully developed to simulate the response of the system to different type of flaws in Al-alloy planar structures and to solve the inverse electromagnetic problem, will be shown.

  14. Neural control of tuneable skin iridescence in squid.

    PubMed

    Wardill, T J; Gonzalez-Bellido, P T; Crook, R J; Hanlon, R T

    2012-10-22

    Fast dynamic control of skin coloration is rare in the animal kingdom, whether it be pigmentary or structural. Iridescent structural coloration results when nanoscale structures disrupt incident light and selectively reflect specific colours. Unlike animals with fixed iridescent coloration (e.g. butterflies), squid iridophores (i.e. aggregations of iridescent cells in the skin) produce dynamically tuneable structural coloration, as exogenous application of acetylcholine (ACh) changes the colour and brightness output. Previous efforts to stimulate iridophores neurally or to identify the source of endogenous ACh were unsuccessful, leaving researchers to question the activation mechanism. We developed a novel neurophysiological preparation in the squid Doryteuthis pealeii and demonstrated that electrical stimulation of neurons in the skin shifts the spectral peak of the reflected light to shorter wavelengths (greater than 145 nm) and increases the peak reflectance (greater than 245%) of innervated iridophores. We show ACh is released within the iridophore layer and that extensive nerve branching is seen within the iridophore. The dynamic colour shift is significantly faster (17 s) than the peak reflectance increase (32 s), revealing two distinct mechanisms. Responses from a structurally altered preparation indicate that the reflectin protein condensation mechanism explains peak reflectance change, while an undiscovered mechanism causes the fast colour shift. PMID:22896651

  15. Impact of SQUIDs on functional imaging in neuroscience

    NASA Astrophysics Data System (ADS)

    Della Penna, Stefania; Pizzella, Vittorio; Romani, Gian Luca

    2014-04-01

    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.

  16. NDE of coated-conductor using HTS SQUID array

    NASA Astrophysics Data System (ADS)

    Hato, T.; Adachi, S.; Sutoh, Y.; Hata, K.; Oshikubo, Y.; Machi, T.; Tanabe, K.

    2009-10-01

    We developed a non-destructive evaluation (NDE) system using an HTS SQUID array in order to examine rare-earth (RE)-123 HTS coated conductors striated into multi-filamentary lines. The 5-channel HTS SQUID gradiometer array was composed of ramp-edge junctions with LaErBaCuO and SmBaCuO electrode layers, and fabricated by using an HTS multi layer fabrication technique. The planar gradiometers with 1 1 mm 2 pickup loops and a baseline of 1 mm detected the vertical element of magnetic field gradient induced around defects by an eddy current. The gradiometer array cooled by thermal conduction from a liquid nitrogen bath was placed above the coated conductor on the main stage with a lift-off of about 1.5 mm. A coated conductor was fed from a reel to reel, and cooled blow its Tc by stages connected to Gifford-Mcmahon (GM) coolers. By employing a 3 kHz induction current generating the maximum field of 0.14 mT, we could identify a distribution of defects in a long-length non-striated conductor. Furthermore, we could detect and distinguish three kinds of defects, existence of a spotty normal-state region, electrical short between striated filaments, and delamination of the superconducting layer from the Hastelloy tape for each filamentary superconducting line at a high speed up to 30 m/h.

  17. SQUID-Detected In Vivo MRI at Microtesla Magnetic Fields

    SciTech Connect

    Moble, Michael; Myers, Whittier R; Lee, SeungKyun; Kelso, Nathan; Hatridge, Michael; Pines, Alexander; Clarke, John

    2005-06-01

    We use a low transition temperature (T{sub c}) Super-conducting Quantum Interference Device (SQUID) to perform in vivo magnetic resonance imaging (MRI) at magnetic fields around 100 microtesla, corresponding to proton Larmor frequencies of about 5 kHz. In such low fields, broadening of the nuclear magnetic resonance lines due to inhomogeneous magnetic fields and susceptibility variations of the sample are minimized, enabling us to obtain high quality images. To reduce environmental noise the signal is detected by a second-order gradiometer, coupled to the SQUID, and the experiment is surrounded by a 3-mm thick Al shield. To increase the signal-to-noise ratio (SNR), we prepolarize the samples in a field up to 100 mT. Three-dimensional images are acquired in less than 6 minutes with a standard spin-echo phase-encoding sequence. Using encoding gradients of {approx}100 {micro}T/m we obtain three-dimensional images of bell peppers with a resolution of 2 x 2 x 8 mm{sup 3}. Our system is ideally suited to acquiring images of small, peripheral parts of the human body such as hands and arms. In vivo images of an arm, acquired at 132 {micro}T, show 24-mm sections of the forearm with a resolution of 3 x 3 mm{sup 2} and a SNR of 10. We discuss possible applications of MRI at these low magnetic fields.

  18. Low-noise rf Amplifiers based on dc SQUIDs

    NASA Astrophysics Data System (ADS)

    Mck, M.; Andr, M.-O.; Clarke, John; Gail, J.; Heiden, C.

    1998-03-01

    Low-Tc dc SQUIDs can be used as tuned or broadband radiofrequency (rf) amplifiers by coupling the signal to the superconducting coil fabricated on the square washer loop. Typically, gains of up to 25 dB at 100 MHz can be achieved. As the frequency is raised, however, the gain drops sharply because the input current increasingly flows through the parasitic capacitance between the coil and the washer, rather than through the coil. In a new design, we take advantage of this parasitic capacitance by connecting the input signal between one end of the input coil and the grounded SQUID washer. Thus, the input coil and the ground plane from a microstrip resonator. At the resonant frequency of the microstrip line, the rf current is enhanced, increasing the gain. In preliminary experiments with 90 mm-long input coils we have achieved a gain of 28 dB at about 150 MHz, and a measured noise temperature of about 1 K. We are currently working to increase the resonant frequency by reducing the length of the microstrip line. The amplifier is intended for use on the axion detector at LLNL.

  19. Model of Auctioneer Estimation of Swordtip Squid (Loligo edulis) Quality

    NASA Astrophysics Data System (ADS)

    Nakamura, Makoto; Matsumoto, Keisuke; Morimoto, Eiji; Ezoe, Satoru; Maeda, Toshimichi; Hirano, Takayuki

    The knowledge of experienced auctioneers regarding the circulation of marine products is an essential skill and is necessary for evaluating product quality and managing aspects such as freshness. In the present study, the ability of an auctioneer to quickly evaluate the freshness of swordtip squid (Loligo edulis) at fish markets was analyzed. Evaluation characteristics used by an auctioneer were analyzed and developed using a fuzzy logic model. Forty boxes containing 247 swordtip squid with mantles measuring 220 mm that had been evaluated and assigned to one of five quality categories by an auctioneer were used for the analysis and the modeling. The relationships between the evaluations of appearance, body color, and muscle freshness were statistically analyzed. It was found that a total of four indexes of the epidermis color strongly reflected evaluations of appearance: dispersion ratio of the head, chroma on the head-end mantle and the difference in the chroma and brightness of the mantle. The fuzzy logic model used these indexes for the antecedent-part of the linguistic rules. The results of both simulation and evaluations demonstrate that the model is robust, with the predicted results corresponding with more than 96% of the quality assignments of the auctioneers.

  20. Integrated Directly-Coupled SQUID Magnetometer and Gradiometer

    NASA Astrophysics Data System (ADS)

    Chang, Chan-Yao; Hsu, Chi-Ming; Jeng, Jen-Tzong

    In this work, we investigated the directly-coupled superconducting quantum interference device (SQUID) magnetometer and gradiometer with integrated pickup loops. To prepare the structures, we fabricated the YBa2Cu3O7-x thin films on strontium titanate (SrTiO3) substrates by magnetron rf sputtering. The devices were patterned by ultraviolet photolithography followed by a three-step wet etching process. The circular and differential modulation coils for the magnetometer and gradiometer, respectively, were wound on bakelite frames attached to the back of the chip mount. The voltage-current and voltage-flux characteristics of option SQUIDs on the chip, which was put in a switching-channel electrical cryostat, were characterized by using the low-noise preamplifier, the homemade currentwaveform generator, and the computer-based data acquisition unit. The magnetometer and the gradiometer can be operated simultaneously by independent flux-locked loops. The proposed sensor can be applied to the nondestructive evaluation and biomagnetic imaging, for example, magnetocardiogram.

  1. Neural control of tuneable skin iridescence in squid

    PubMed Central

    Wardill, T. J.; Gonzalez-Bellido, P. T.; Crook, R. J.; Hanlon, R. T.

    2012-01-01

    Fast dynamic control of skin coloration is rare in the animal kingdom, whether it be pigmentary or structural. Iridescent structural coloration results when nanoscale structures disrupt incident light and selectively reflect specific colours. Unlike animals with fixed iridescent coloration (e.g. butterflies), squid iridophores (i.e. aggregations of iridescent cells in the skin) produce dynamically tuneable structural coloration, as exogenous application of acetylcholine (ACh) changes the colour and brightness output. Previous efforts to stimulate iridophores neurally or to identify the source of endogenous ACh were unsuccessful, leaving researchers to question the activation mechanism. We developed a novel neurophysiological preparation in the squid Doryteuthis pealeii and demonstrated that electrical stimulation of neurons in the skin shifts the spectral peak of the reflected light to shorter wavelengths (greater than 145 nm) and increases the peak reflectance (greater than 245%) of innervated iridophores. We show ACh is released within the iridophore layer and that extensive nerve branching is seen within the iridophore. The dynamic colour shift is significantly faster (17 s) than the peak reflectance increase (32 s), revealing two distinct mechanisms. Responses from a structurally altered preparation indicate that the reflectin protein condensation mechanism explains peak reflectance change, while an undiscovered mechanism causes the fast colour shift. PMID:22896651

  2. Evidence for myosin motors on organelles in squid axoplasm.

    PubMed Central

    Bearer, E L; DeGiorgis, J A; Bodner, R A; Kao, A W; Reese, T S

    1993-01-01

    Squid axoplasm has proved a rich source for the identification of motors involved in organelle transport. Recently, squid axoplasmic organelles have been shown to move on invisible tracks that are sensitive to cytochalasin, suggesting that these tracks are actin filaments. Here, an assay is described that permits observation of organelles moving on unipolar actin bundles. This assay is used to demonstrate that axoplasmic organelles move on actin filaments in the barbed-end direction, suggesting the presence of a myosin motor on axoplasmic organelles. Indeed, axoplasm contains actin-dependent ATPase activity, and a pan-myosin antibody recognized at least four bands in Western blots of axoplasm. An approximately 235-kDa band copurified in sucrose gradients with KI-extracted axoplasmic organelles, and the myosin antibody stained the organelle surfaces by immunogold electron microscopy. The myosin is present on the surface of at least some axoplasmic organelles and thus may be involved in their transport through the axoplasm, their movement through the cortical actin in the synapse, or some other aspect of axonal function. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8248236

  3. Defect detection in thick aircraft samples using HTS SQUID magnetometers

    NASA Astrophysics Data System (ADS)

    Kreutzbruck, M. v.; Allweins, K.; Gierelt, G.; Krause, H.-J.; Grtner, S.; Wolf, W.

    2002-03-01

    Although the sensitivity of the magnetic field sensor is important for many applications in electromagnetic testing, SQUID sensors are usually employed for other reasons. For successful defect detection, properties such as high linearity, large dynamic range, and good spatial resolution are required. We present the implementation of a SQUID magnetometer in an eddy current testing system for the measurement of very thick structures of large aircrafts. A three-layer aluminium sample from EADS Airbus was measured, with a total thickness of 62 mm, resembling the projected outer wing splice of the Airbus A-380. The sample has bolted joints and second-layer cracks adjacent to the titanium bolts. The combination of field sensitivities of a few pT/?Hz and a large dynamic range of about 140 dB/?Hz at low frequencies enables us to detect defects at a depth of up to 40 mm in aluminium. For sufficient current penetration into the layered aluminium sample, remarkably low excitation frequencies in the range of 10-40 Hz are required. The small field variations caused by the defects are superimposed on the current distortions and the corresponding field changes in the vicinity of the titanium bolts. Separation of these two contributions requires additional efforts in signal processing and simulations. The measurements were complemented by 3D-FEM calculations in order to find proper excitation frequencies, thus providing an easier separation of flaw signatures from structural background signals.

  4. Optical and mid-infrared neon abundance determinations in star-forming regions

    NASA Astrophysics Data System (ADS)

    Dors, Oli L.; Hgele, Guillermo F.; Cardaci, Mnica V.; Prez-Montero, Enrique; Krabbe, ngela C.; Vlchez, Jos M.; Sales, Dinalva A.; Riffel, Rogrio; Riffel, Rogemar A.

    2013-07-01

    We have used observational spectroscopic data of star-forming regions compiled from the literature and photoionization models to analyse the neon ionic abundances obtained using both optical and mid-infrared emission lines. Comparing Ne++/H+ ionic abundances from distinct methods, we have found that, on average, the abundances obtained via infrared emission lines are higher than those obtained via optical lines, by a factor of 4. Photoionization models with abundance variations along the radius of the hypothetical nebula provide a possible explanation for a large part of the difference between ionic abundances via optical and infrared emission lines. The ionization correction factor (ICF) for the neon is obtained from direct determinations of ionic fractions using infrared emission lines. We derive a constant Ne/O ratio (log Ne/O ? -0.70) for a large range of metallicities, independently of the ICF used to compute the neon total abundance.

  5. Photochemistry of the ozone-water complex in cryogenic neon, argon, and krypton matrixes.

    PubMed

    Tsuge, Masashi; Tsuji, Kazuhide; Kawai, Akio; Shibuya, Kazuhiko

    2013-12-12

    The photochemistry of ozone-water complexes and the wavelength dependence of the reactions were studied by matrix isolation FTIR spectrometry in neon, argon, and krypton matrixes. Hydrogen peroxide was formed upon the irradiation of UV light below 355 nm. Quantitative analyses of the reactant and product were performed to evaluate the matrix cage effect of the photoreaction. In argon and krypton matrixes, a bimolecular O((1)D) + H2O → H2O2 reaction was found to occur to form hydrogen peroxide, where the O((1)D) atom generated by the photolysis of ozone diffused in the cryogenic solids to encounter water. In a neon matrix, hydrogen peroxide was generated through intracage photoreaction of the ozone-water complex, indicating that a neon matrix medium is most appropriate to study the photochemistry of the ozone-water complex. PMID:24252115

  6. NEON: Developing a Platform for Regional to Continental Scale Biological Inquiry

    NASA Astrophysics Data System (ADS)

    Goldman, J.

    2004-05-01

    Climate variation, introductions of alien species, and patterns of land use are some of the important interacting drivers of biological change that are affecting our nation's ecosystems. Many of these drivers operate over large spatial and temporal scales, and our understanding of how these phenomena interact to drive biological change is limited by our inability to link traditionally local and short-term ecological approaches to larger and longer scales. Similarly, our ability to forecast such changes and respond to their consequences is constrained. The National Ecological Observatory Network (NEON) is a proposed shared-use research and education platform intended to improve our capacity to understand and predict biological phenomena operating from regional to continental scales. NEON is envisioned as a system of field and laboratory-based facilities distributed across the United States, which will provide the physical infrastructure and human capabilities necessary to coordinate and integrate research and education campaigns on the following types of issues: (1) biodiversity, species composition, and ecosystem functioning; (2) ecological aspects of biogeochemical cycles; (3) ecological implications of climate change; (4) ecology and evolution of infectious disease; (5) invasive species; and (6) land use and habitat alteration. Themes such as data sharing, multidisciplinary collaboration, and the development of technologies for sensing, forecasting, and visualizing biological information are central to the NEON concept. Development of the NEON science plan and the design of the network itself are proceeding through a variety of workshops and community planning meetings. A national project office is expected to form toward the end of 2004 to lead the development and creation of NEON. Ultimately, the project office will reside within an independent national organization devoted to the coordinated operation of NEON for the scientific community.

  7. Wisdom from the fly.

    PubMed

    Rieder, Leila E; Larschan, Erica N

    2014-11-01

    Arguably, almost all research in Drosophila can be considered basic research, yet many of the most essential and fundamental concepts of human genetics were first decoded in the fly. Although the fly genome, which is organized into only four chromosomes, is approximately one-twentieth the size of the human genome, it contains roughly the same number of genes, and up to 75% of human disease-related genes have Drosophila homologues [1]. The fly was prized for its simplicity and utility even before such compelling homology with humans was apparent. Since Thomas Hunt Morgan began his seminal experiments over a century ago (Table 1), the Drosophila system has revealed countless key mechanisms by which cells function, including the factors that maintain chromatin and the signaling pathways that control cell fate determination and organism development. More recently, the fly has emerged as a critical neurobiological tool and disease model for a range of genetic disorders. In this review, we present a brief retrospective of Drosophila as an indispensable genetic system and discuss some of the many contributions, past and present, of this facile system to human genetics. PMID:25161083

  8. Flying High with Spring.

    ERIC Educational Resources Information Center

    Harrington, Carolyn Lang

    2000-01-01

    Presents an art activity for first grade that uses multicolor scratch paper. Explains that students make scratch-drawings of bird nests, then, as a class, discuss types of birds and bird positions (such as sitting or flying), and finally each creates a bird to add to the nest. (CMK)

  9. Go Fly a Kite

    ERIC Educational Resources Information Center

    Klopack, Ken

    2009-01-01

    This article describes an "art kite" activity. The idea is to construct and decorate a non-flying kite that they could display for an art exhibit. Through the activity, students learn to give and take suggestions from one another, improve the quality of their work and set a wonderful atmosphere of collaboration. (Contains 1 online resource.)

  10. Fly on the Wall

    ERIC Educational Resources Information Center

    Berry, Dave; Korpan, Cynthia

    2009-01-01

    This paper describes the implementation of a peer observation program at the University of Victoria called the Lecture Club. The observers are not interactive during the class--they are the proverbial flies on the wall. The paper identifies the program as self-developmental, discussing the attributes of this learning-to-teach and peer-sharing…

  11. Liquid neon heat transfer as applied to a 30 tesla cryomagnet

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1975-01-01

    A 30-tesla magnet design is studied which calls for forced convection liquid neon heat transfer in small coolant channels. The design also requires suppressing boiling by subjecting the fluid to high pressures through use of magnet coils enclosed in a pressure vessel which is maintained at the critical pressure of liquid neon. This high pressure reduces the possibility of the system flow instabilities which may occur at low pressures. The forced convection heat transfer data presented were obtained by using a blowdown technique to force the fluid to flow vertically through a resistance heated, instrumented tube.

  12. Cooperative lifetime reduction of single acene molecules attached to the surface of neon clusters

    NASA Astrophysics Data System (ADS)

    Mller, Markus; Izadnia, Sharareh; Vlaming, Sebastiaan M.; Eisfeld, Alexander; LaForge, Aaron; Stienkemeier, Frank

    2015-09-01

    Tetracene and pentacene molecules attached to the surface of neon clusters have been spectroscopically investigated. The fluorescence spectra indicate that the molecules are immobilized on the surface and, to a large extent, do not form complexes. By varying the number of attached molecules, laser power, or neon cluster size, we find a systematic fluorescence lifetime reduction up to a factor of 20 indicating a cooperative coupling in our system. For averaged intermolecular distances greater than 33 , we attribute the reduction in fluorescence lifetime to Dicke superradiance, while for smaller intermolecular distances, nonradiative decay mechanisms cause additional lifetime reduction.

  13. A cost-effective approach to microporate mammalian cells with the Neon Transfection System.

    PubMed

    Brees, Chantal; Fransen, Marc

    2014-12-01

    Electroporation is one of the most efficient nonviral methods for transferring exogenous DNA into mammalian cells. However, the relatively high costs of electroporation kits and reagents temper the routine use of this fast and easy to perform technique in many laboratories. Several years ago, a new flexible and easy to operate electroporation device was launched under the name Neon Transfection System. This device uses specialized pipette tips containing gold-plated electrodes as electroporation chamber. Here we report a protocol to regenerate these expensive tips as well as some other Neon kit accessories, thereby reducing the cost of electroporation at least 10-fold. PMID:25172131

  14. Influence of Squid Liver Powder on Accumulation of Cadmium in Serum, Kidney and Liver of Mice

    PubMed Central

    Kim, Byoung-Mok; Lee, Soo-Young; Jeong, In-Hak

    2013-01-01

    In this study, the effect of squid liver powder intake on accumulation of cadmium in mice was investigated. Subjects were divided into 4 groups including the control group (CON), squid liver powder group with lipids not removed (SLP100), and squid liver powder groups with lipids removed (LFSLP50 and LFSLP100). Feed intake and food efficiency ratio of squid liver powder groups was significantly higher than the CON. As a result of investigating cadmium content in hair, serum, liver, and kidney during intake of squid liver powder, all groups showed increase in cadmium accumulation through consistent, long-term intake. Especially, cadmium content in liver and kidney of LFSLP100 was significantly higher than the content of SLP100 and CON. As a result of pathological observation on liver and kidney tissues according to squid liver powder diet, LFSLP100 showed most serious pathological symptoms. In case of kidney tissues, degeneration was significantly more severe in LFSLP100 compared to other groups. Such results suggest that cadmium concentration in human body can be increased by ingestion of whole squid including internal organs and that tissues can be damaged by increased cadmium concentration. More specific and systematic studies are deemed necessary. PMID:24471103

  15. Laboratory evaluation of novaluron for controlling larval horn flies, house flies, and stable flies (Diptera: Muscidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A granular formulation of novaluron (Novaluron 0.2G, 0.2% AI), a newer benzoylphenyl urea insecticide, was evaluated for its efficacy in controlling the larval stage of horn flies, Haematobia irritans (Linnaeus), house flies, Musca domestica Linnaeus, and stable flies, Stomoxys calcitrans (Linnaeus)...

  16. An annotated checklist of the horse flies, deer flies, and yellow flies (Diptera: Tabanidae) of Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The family Tabanidae includes the horse flies, deer flies, and yellow flies and is considered a significant pest of livestock throughout the United States, including Florida. Tabanids can easily become a major pest of man, especially salt marsh species which are known to readily feed on humans and o...

  17. Aminoglycoside-induced damage in the statocyst of the longfin inshore squid, Doryteuthis pealeii.

    PubMed

    Scharr, Alexandra L; Mooney, T Aran; Schweizer, Felix E; Ketten, Darlene R

    2014-08-01

    Squid are a significant component of the marine biomass and are a long-established model organism in experimental neurophysiology. The squid statocyst senses linear and angular acceleration and is the best candidate for mediating squid auditory responses, but its physiology and morphology are rarely studied. The statocyst contains mechano-sensitive hair cells that resemble hair cells in the vestibular and auditory systems of other animals. We examined whether squid statocyst hair cells are sensitive to aminoglycosides, a group of antibiotics that are ototoxic in fish, birds, and mammals. To assess aminoglycoside-induced damage, we used immunofluorescent methods to image the major cell types in the statocyst of longfin squid (Doryteuthis pealeii). Statocysts of live, anesthetized squid were injected with either a buffered saline solution or neomycin at concentrations ranging from 0.05 to 3.0 mmol l(-1). The statocyst hair cells of the macula statica princeps were examined 5 h post-treatment. Anti-acetylated tubulin staining showed no morphological differences between the hair cells of saline-injected and non-injected statocysts. The hair cell bundles of the macula statica princeps in aminoglycoside-injected statocysts were either missing or damaged, with the amount of damage being dose-dependent. The proportion of missing hair cells did not increase at the same rate as damaged cells, suggesting that neomycin treatment affects hair cells in a nonlethal manner. These experiments provide a reliable method for imaging squid hair cells. Further, aminoglycosides can be used to induce hair cell damage in a primary sensory area of the statocyst of squid. Such results support further studies on loss of hearing and balance in squid. PMID:25216502

  18. Detection of small magnetic fields using thick BSCCO film RF squid operating at 77 K

    NASA Astrophysics Data System (ADS)

    Khare, N.; Gupta, A. K.; Chaudhry, S.

    A high Tc RF SQUID fabricated from thick BSCCO film using naturally present grain boundary weak links has been used for measuring small magnetic fields originating from an analogue quartz wrist watch and magnetic rock samples. For these measurements, the samples were kept at ambient temperature at a distance of ?4 cm from the SQUID, which was operated in the 'locked mode' at 77 K. The flux noise density of the SQUID in the white noise region was 5 10 -4 ? 0 Hz - 1/2 at 77 K.

  19. A tuned NMR spectrometer using a DC SQUID for systems of low spin density

    NASA Astrophysics Data System (ADS)

    Dyball, H.; Li, Junyun; Lusher, C. P.; Cowan, B. P.; Saunders, J.; Drung, D.; Schurig, T.

    2000-07-01

    We are using a low Tc DC SQUID as the first-stage amplifier in an NMR spectrometer designed for the study of systems of low spin density. The NMR pickup coil forms part of a series tuned tank circuit attached to the input coil of the SQUID. The tank circuit resonant frequency is close to 1 MHz. The SQUID amplifier uses additional positive feedback (APF) and operates in flux-locked loop mode with a bandwidth of 1.6 MHz. Preliminary measurements on 3He samples are reported.

  20. A SQUID-based microwave cavity search for dark-matter axions

    SciTech Connect

    Asztalos, S J; Carosi, G; Hagmann, C; Kinion, D; van Bibber, K; Hotz, M; Rosenberg, L; Rybka, G; Hoskins, J; Hwang, J; Sikivie, P; Tanner, D B; Bradley, R; Clarke, J

    2009-10-21

    Axions in the {mu}eV mass range are a plausible cold dark matter candidate and may be detected by their conversion into microwave photons in a resonant cavity immersed in a static magnetic field. The first result from such an axion search using a superconducting first-stage amplifier (SQUID) is reported. The SQUID amplifier, replacing a conventional GaAs field-effect transistor amplifier, successfully reached axion-photon coupling sensitivity in the band set by present axion models and sets the stage for a definitive axion search utilizing near quantum-limited SQUID amplifiers.

  1. Magnetic calorimeter with a SQUID for detecting weak radiations and recording the ultralow energy release

    SciTech Connect

    Golovashkin, Aleksander I; Zherikhina, L N; Kuleshova, G V; Tskhovrebov, A M; Izmailov, G N

    2006-12-31

    The scheme of a magnetic calorimeter for recording extremely low energy releases is developed. The calorimeter is activated by the method of adiabatic demagnetisation and its response to the energy release is measured with a superconducting quantum interference device (SQUID). The estimate of the ultimate sensitivity of the calorimeter with the SQUID demonstrates the possibilities of its application for detecting ultralow radiation intensity, recording single X-ray quanta in the proportional regime and other events with ultralow energy releases. The scheme of the calorimeter with the SQUID on matter waves in superfluid {sup 4}He is proposed. (radiation detectors)

  2. Generation of N-qubit W states with rf SQUID qubits by adiabatic passage

    SciTech Connect

    Deng, Z. J.; Gao, K. L.; Feng, M.

    2006-12-15

    A simple scheme is presented to generate N-qubit W states with rf superconducting quantum interference devices (SQUIDs) in cavity QED through adiabatic passage. Because of the achievable strong coupling for rf SQUID qubits embedded in cavity QED, we can get the desired state with high success probability. Furthermore, the scheme is insensitive to the position inaccuracy of the rf SQUID. Numerical simulation shows that, by using present experimental techniques, we can achieve our scheme with very high success probability, and the fidelity could eventually be unity with the help of dissipation.

  3. A SQUID readout system for a superconducting gyroscope. [superconducting quantum interference device

    NASA Technical Reports Server (NTRS)

    Hendricks, J. B.

    1975-01-01

    A design of a read out system for a superconducting gyroscope to be used in an orbiting gyroscope relativity experiment is discussed. The 'London Moment' of the superconducting rotor, which lies along the spin axis of the rotor, will be measured with a SQUID-type magnetometer. The SQUID will be built around the gyro rotor, with a very close spacing to give an inductance between 10 millionths and 1 millionth Hy. A SQUID of this design should resolve 2.07 times 10 to the minus 19th weber. The angular resolution of the gyroscope will then be 0.0035 arc-second, which is sufficient for the intended experiment.

  4. Multichannel DC SQUID sensor array for biomagnetic applications

    SciTech Connect

    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. )

    1991-03-01

    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{sup 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).

  5. Analogues of red and white muscle in squid mantle

    PubMed Central

    Mommsen, T. P.; Ballantyne, J.; MacDonald, D.; Gosline, J.; Hochachka, P. W.

    1981-01-01

    In five species of squid, varying in life-style from fast-swimming pelagic predators to sluggish benthic forms, the circular muscle of the mantle was found to be metabolically and structurally differentiated into inner, middle, and outer zones. In the middle zone, mitochondrial abundance and the ratios of oxidative to glycolytic enzyme activities were low. This zone was sandwiched between thinner bands of muscle lining both the inner and outer edges of the mantle. In these bands, mitochondrial abundance and the ratios of oxidative to glycolytic enzyme activities were high. It is proposed that this metabolic differentiation is analogous to the development of red and white muscles in vertebrates and that it serves a similar function, white muscle mainly supporting burst-type swimming and red muscle sustaining steady-state oxidative work. Images PMID:16593022

  6. The Transition from Stiff to Compliant Materials in Squid Beaks

    NASA Astrophysics Data System (ADS)

    Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W.; Waite, J. Herbert

    2008-03-01

    The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-L-alanine (dopa) and undergo extensive stabilization by histidyl-dopa cross-link formation. These findings may serve as a foundation for identifying design principles for attaching mechanically mismatched materials in engineering and biological applications.

  7. The transition from stiff to compliant materials in squid beaks.

    PubMed

    Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W; Waite, J Herbert

    2008-03-28

    The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-L-alanine (dopa) and undergo extensive stabilization by histidyl-dopa cross-link formation. These findings may serve as a foundation for identifying design principles for attaching mechanically mismatched materials in engineering and biological applications. PMID:18369144

  8. SQUID-Detected Microtesla MRI in the presence of Metal

    SciTech Connect

    Moessle, Michael; Han, Song-I.; Myers, Whittier; Lee, Seung-Kyun; Kelso, Nathan; Hatridge, Michael; Pines, Alexander; Clarke, John

    2006-09-06

    In magnetic resonance imaging (MRI) performed at fields of 1 T and above, the presence of a metal insert can distort the image because of susceptibility differences within the sample and modification of the radiofrequency fields by screening currents. Furthermore, it is not feasible to perform nuclear magnetic resonance (NMR) spectroscopy or acquire a magnetic resonance image if the sample is enclosed in a metal container. Both problems can be overcome by substantially lowering the NMR frequency. Using a microtesla imaging system operating at 2.8 kHz, with a superconducting quantum interference device (SQUID) as the signal detector, we have obtained distortion-free images of a phantom containing a titanium bar and three-dimensional images of an object enclosed in an aluminum can; in both cases high-field images are inaccessible.

  9. Optimization of the leak conductance in the squid giant axon

    NASA Astrophysics Data System (ADS)

    Seely, Jeffrey; Crotty, Patrick

    2010-08-01

    We report on a theoretical study showing that the leak conductance density, GL , in the squid giant axon appears to be optimal for the action potential firing frequency. More precisely, the standard assumption that the leak current is composed of chloride ions leads to the result that the experimental value for GL is very close to the optimal value in the Hodgkin-Huxley model, which minimizes the absolute refractory period of the action potential, thereby maximizing the maximum firing frequency under stimulation by sharp, brief input current spikes to one end of the axon. The measured value of GL also appears to be close to optimal for the frequency of repetitive firing caused by a constant current input to one end of the axon, especially when temperature variations are taken into account. If, by contrast, the leak current is assumed to be composed of separate voltage-independent sodium and potassium currents, then these optimizations are not observed.

  10. Coupling of Retinal, Protein, and Water Dynamics in Squid Rhodopsin

    PubMed Central

    Jardn-Valadez, Eduardo; Bondar, Ana-Nicoleta; Tobias, Douglas J.

    2010-01-01

    The light-induced isomerization of the retinal from 11-cis to all-trans triggers changes in the conformation of visual rhodopsins that lead to the formation of the activated state, which is ready to interact with the G protein. To begin to understand how changes in the structure and dynamics of the retinal are transmitted to the protein, we performed molecular dynamics simulations of squid rhodopsin with 11-cis and all-trans retinal, and with two different force fields for describing the retinal molecule. The results indicate that structural rearrangements in the binding pocket, albeit small, propagate toward the cytoplasmic side of the protein, and affect the dynamics of internal water molecules. The sensitivity of the active-site interactions on the retinal force-field parameters highlights the coupling between the retinal molecule and its immediate protein environment. PMID:20923654

  11. Multimodal transition and stochastic antiresonance in squid giant axons

    NASA Astrophysics Data System (ADS)

    Borkowski, L. S.

    2010-10-01

    The experimental data of Takahashi [Physica D 43, 318 (1990)]10.1016/0167-2789(90)90140-K, on the response of squid giant axons stimulated by periodic sequence of short current pulses is interpreted within the Hodgkin-Huxley model. The minimum of the firing rate as a function of the stimulus amplitude I0 in the high-frequency regime is due to the multimodal transition. Below this singular point only odd multiples of the driving period remain and the system is sensitive to noise. The coefficient of variation has a maximum and the firing rate has a minimum as a function of the noise intensity, which is an indication of the stochastic coherence antiresonance. The model calculations reproduce the frequency of occurrence of the most common modes in the vicinity of the transition. A linear relation of output frequency vs I0 above the transition is also confirmed.

  12. Multimodal transition and stochastic antiresonance in squid giant axons.

    PubMed

    Borkowski, L S

    2010-10-01

    The experimental data of Takahashi [Physica D 43, 318 (1990)], on the response of squid giant axons stimulated by periodic sequence of short current pulses is interpreted within the Hodgkin-Huxley model. The minimum of the firing rate as a function of the stimulus amplitude I0 in the high-frequency regime is due to the multimodal transition. Below this singular point only odd multiples of the driving period remain and the system is sensitive to noise. The coefficient of variation has a maximum and the firing rate has a minimum as a function of the noise intensity, which is an indication of the stochastic coherence antiresonance. The model calculations reproduce the frequency of occurrence of the most common modes in the vicinity of the transition. A linear relation of output frequency vs I0 above the transition is also confirmed. PMID:21230315

  13. Test What You Fly?

    NASA Astrophysics Data System (ADS)

    Margolies, Don

    2002-10-01

    It was the first time on any NASA project I know of that all the instruments on an observatory came off for rework or calibration after the full range of environmental tests, and then were reintegrated at the launch center without the benefit of an observatory environmental retest. Perhaps you've heard the expression, 'Test what you fly, fly what you test'? In theory, it's hard to argue with that. In this case, I was willing to take the risk of not testing what I flew. As the project manager for the Advanced Composition Explorer (ACE) mission, I was the one who ultimately decided what risks to take, just as it was my responsibility to get buy-in from the stakeholders.

  14. Test What You Fly?

    NASA Technical Reports Server (NTRS)

    Margolies, Don

    2002-01-01

    It was the first time on any NASA project I know of that all the instruments on an observatory came off for rework or calibration after the full range of environmental tests, and then were reintegrated at the launch center without the benefit of an observatory environmental retest. Perhaps you've heard the expression, 'Test what you fly, fly what you test'? In theory, it's hard to argue with that. In this case, I was willing to take the risk of not testing what I flew. As the project manager for the Advanced Composition Explorer (ACE) mission, I was the one who ultimately decided what risks to take, just as it was my responsibility to get buy-in from the stakeholders.

  15. Flies With Skin Blisters.

    PubMed

    Simons, Matias

    2015-08-01

    Epidermolysis bullosa simplex (EBS) belongs to a family of genetic conditions that cause the skin to be fragile and to blister easily. Although most of the genes involved are known, the molecular mechanisms underlying keratin aggregation remain obscure. In this issue of the Journal, Bohnekamp et al. report on a novel EBS model that is based on the de novo formation of keratin filaments in "keratin null flies." PMID:26174537

  16. Fly-scan ptychography

    SciTech Connect

    Huang, Xiaojing; Lauer, Kenneth; Clark, Jesse N.; Xu, Weihe; Nazaretski, Evgeny; Harder, Ross; Robinson, Ian K.; Chu, Yong S.

    2015-03-13

    We report an experimental ptychography measurement performed in fly-scan mode. With a visible-light laser source, we demonstrate a 5-fold reduction of data acquisition time. By including multiple mutually incoherent modes into the incident illumination, high quality images were successfully reconstructed from blurry diffraction patterns. This approach significantly increases the throughput of ptychography, especially for three-dimensional applications and the visualization of dynamic systems.

  17. Flying Saucer? Aliens?

    NASA Technical Reports Server (NTRS)

    1961-01-01

    No, it's not a flying saucer, it is the domed top to a 70 foot long vacuum tank at the Lewis Research Center's Electric Propulsion Laboratory, Cleveland, Ohio. The three technicians shown here in protective clothing had just emerged from within the tank where they had been cleaning in the toxic mercury atmosphere, left after ion engine testing in the tank. Lewis has since been renamed the John H. Glenn Research Center.

  18. Fly-scan ptychography

    PubMed Central

    Huang, Xiaojing; Lauer, Kenneth; Clark, Jesse N.; Xu, Weihe; Nazaretski, Evgeny; Harder, Ross; Robinson, Ian K.; Chu, Yong S.

    2015-01-01

    We report an experimental ptychography measurement performed in fly-scan mode. With a visible-light laser source, we demonstrate a 5-fold reduction of data acquisition time. By including multiple mutually incoherent modes into the incident illumination, high quality images were successfully reconstructed from blurry diffraction patterns. This approach significantly increases the throughput of ptychography, especially for three-dimensional applications and the visualization of dynamic systems. PMID:25766519

  19. Light-sensitive motile iridophores and visual pigments in the neon tetra, Paracheirodon innesi.

    PubMed

    Kasai, Akiko; Oshima, Noriko

    2006-09-01

    Although motile iridophores in the longitudinal stripes of neon tetra skin are under control of the sympathetic nervous system, they also respond to light directly and show circadian color changes. Using neon tetra skin, we found that the photoresponse of iridophores depends on light intensity, and that light near 500 nm is most effective. RT-PCR demonstrated the expression of mRNAs encoding rhodopsin and two kinds of cone opsins (Pi-green1 and Pi-green2) in neon tetra skin where the light-sensitive iridophores exist. These mRNAs are also expressed in the lateral eyes. The cone opsin genes, Pi-green1 and Pi-green2, show high similarity with the g101 and g103 genes of unique green cone opsins (belonging to the MWS/LWS group) of the blind Mexican cavefish. These results show that Pi-green1, Pi-green2, and/or rhodopsin may play important roles in the photoresponse of neon tetra iridophores, which are most sensitive to light near 500 nm. PMID:17043404

  20. Building complex heterogeneous measurement and data systems: Combining ecology and systems engineering at NEON

    NASA Astrophysics Data System (ADS)

    Berukoff, S. J.

    2013-12-01

    The National Ecological Observatory Network (NEON) is an NSF-funded facility to enable the understanding of how ecological processes occurring on multiple spatial and temporal scales are inter-related, through the deployment of measurement and observation infrastructure across the continental US, Alaska, Hawaii, and Puerto Rico. Two overriding features of NEON's design are an emphasis on the integration of system engineering principles with this infrastructure deployment, and the deep involvement, since its inception, of the ecological community in helping to define, shape, and realize NEON's potential. This synergy is being leveraged to build a novel, unique facility that will be both nimble and long-lived. We discuss first how traditional systems engineering principles, typically applied only to instrumental systems, are being applied to the wide array of NEON measurement and observation infrastructure, both to achieve construction completion but also to serve as a consistent and informative guide to building infrastructure for ecological and environmental research. We also describe how the scientific and engineering community has contributed to these activities, and derive some important guiding principles within their synergy.

  1. Dielectric Properties of Cryogenic Gas Mixtures Containing Helium, Neon, and Hydrogen

    NASA Astrophysics Data System (ADS)

    Graber, L.; Kim, W. J.; Cheetham, P.; Kim, C. H.; Rodrigo, H.; Pamidi, S. V.

    2015-12-01

    Past efforts of cooling high temperature superconducting (HTS) power cables by gaseous cryogens focused exclusively on helium. The limited dielectric strength of helium gas necessitated alternatives that could be used in the temperature range suitable for HTS power applications. This paper presents the benefits of gas mixtures containing helium with small concentrations of hydrogen or neon to mitigate the limited dielectric strength of pure helium gas. The expectation was that such gas mixtures could improve dielectric characteristics while maintaining the thermal, non-flammable and non-corrosive properties of pure helium gas. The AC breakdown voltage of helium gas mixtures containing 4 mol% neon or 4 mol% hydrogen respectively have been measured and compared to those of pure helium and pure neon. All measurements were performed at 77 K at gas pressure levels between 0.5 and 2.0 MPa. While the 4 mol% neon mixture did not result in any improvement over pure helium, the 4 mol% hydrogen mixture resulted in 80% higher breakdown strength. This is expected to enable higher operating voltages for gas cooled HTS power devices.

  2. Helium-neon laser radiation effect on some teratogenic processes in fish embryos

    NASA Astrophysics Data System (ADS)

    Uzdensky, Anatoly B.; Gorbacheva, Ludmila T.; Vorob'eva, Olga A.; Son, Chor-gun

    2001-07-01

    Helium-neon laser irradiation increased production of normal fish hatchlings as a result of eggs irradiation at gastrulation and embryonal motorics stages and negatively influenced at organogenesis stage. Role of main contributing factors-embryos survival and morphological anomalies in this process is investigated.

  3. The Form and Dimensions of the Giant Synapse of Squids

    NASA Astrophysics Data System (ADS)

    Martin, R.; Miledi, R.

    1986-03-01

    A study was made of the distal giant synapse, and of proximal synapses, in the stellate ganglion of the squid, Loligo vulgaris. For this purpose we injected iontophoretically dyes or cobalt ions into the pre- or postsynaptic axon. The intra-axonal movement of visible dyes was measured. Both presynaptic fibres, the main second order giant axon and the largest accessory axon, branched to make multiple synaptic contacts on the giant motor axons from near the perikarya down to near the exit of the stellar nerves from the ganglion. There were considerable individual variations in the branching patterns of the presynaptic giant axon and in the course and number of the postsynaptic giant axons. More than one accessory axon made contact with the largest motor axon. Fine structural details of the synapse are presented. The size of the contact area made by the main presynaptic axon on the last postsynaptic axon of a medium-sized animal was estimated from low power electron micrographs. We measured and counted synaptic contacts, synaptic vesicles and mitochondria. The fine structure of proximal synapses was found to be very similar to that of the distal synapse. Cobalt- or dye-injected ganglia showed that the perikarya of the axons which fuse to form the postsynaptic giant axons are located in diffuse and overlapping areas of the giant fibre lobe. In freshly hatched larvae the giant synapse was well differentiated; a gradient of differentiation from brain to periphery was detectable. The distal giant synapses of the oegopsid squid Todarodes sagittatus and of Sepia officinalis differed from the Loligo synapse. In Todarodes and Sepia collaterals and processes from both the presynaptic and the postsynaptic giant fibres are shown to meet in numerous contacts in the enlarged sheath surrounding the third order axon. In several respects the Loligo giant fibre system appears to represent in phylogenetical order the more evolved neuronal network.

  4. Colonization of Euprymna scolopes squid by Vibrio fischeri.

    PubMed

    Naughton, Lynn M; Mandel, Mark J

    2012-01-01

    Specific bacteria are found in association with animal tissue. Such host-bacterial associations (symbioses) can be detrimental (pathogenic), have no fitness consequence (commensal), or be beneficial (mutualistic). While much attention has been given to pathogenic interactions, little is known about the processes that dictate the reproducible acquisition of beneficial/commensal bacteria from the environment. The light-organ mutualism between the marine Gram-negative bacterium V. fischeri and the Hawaiian bobtail squid, E. scolopes, represents a highly specific interaction in which one host (E. scolopes) establishes a symbiotic relationship with only one bacterial species (V. fischeri) throughout the course of its lifetime. Bioluminescence produced by V. fischeri during this interaction provides an anti-predatory benefit to E. scolopes during nocturnal activities, while the nutrient-rich host tissue provides V. fischeri with a protected niche. During each host generation, this relationship is recapitulated, thus representing a predictable process that can be assessed in detail at various stages of symbiotic development. In the laboratory, the juvenile squid hatch aposymbiotically (uncolonized), and, if collected within the first 30-60 minutes and transferred to symbiont-free water, cannot be colonized except by the experimental inoculum. This interaction thus provides a useful model system in which to assess the individual steps that lead to specific acquisition of a symbiotic microbe from the environment. Here we describe a method to assess the degree of colonization that occurs when newly hatched aposymbiotic E. scolopes are exposed to (artificial) seawater containing V. fischeri. This simple assay describes inoculation, natural infection, and recovery of the bacterial symbiont from the nascent light organ of E. scolopes. Care is taken to provide a consistent environment for the animals during symbiotic development, especially with regard to water quality and light cues. Methods to characterize the symbiotic population described include (1) measurement of bacterially-derived bioluminescence, and (2) direct colony counting of recovered symbionts. PMID:22414870

  5. Satellite formation flying

    NASA Astrophysics Data System (ADS)

    Yan, Qiguo

    2002-09-01

    The control of Distributed Satellite Formation Flying (DSFF) has attracted the attention of many researchers over the past decade. The increasing stringent performance specifications required for controlling DSFF systems necessitates the accurate maintenance of the relative positions/orientations of the participating satellites. This research focuses on the development of new effective controllers for DSFF system via various linear and nonlinear approaches. Based on the classical Hill's equation, a mathematically rigorous control design framework is proposed for linear control of DSFF with guaranteed closed-loop stability. In particular, a pulse-based, periodic gain, control architectures is developed which utilize intermittent control action. Next, a Lyapunov-based, nonlinear adaptive control law is designed which guarantees global asymptotic convergence of position tracking error. In addition, a nonlinear, output feedback control law for DSFF is presented, which guarantees global uniformly ultimately bounded position and velocity tracking error in the presence of some DSFF system parametric uncertainties. Another contribution of this research consists of the development of the perturbative control of satellite flying around the oblate earth which can pave the way for its direct application of one class of optimal formation flying in polar orbits. Numerical simulations are presented to demonstrate the efficacies of the proposed control design methodologies.

  6. SQUID-Detected Magnetic Resonance Imaging in MicroteslaFields

    SciTech Connect

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2006-08-14

    Magnetic resonance imaging (MRI) has developed into a powerful clinical tool for imaging the human body (1). This technique is based on nuclear magnetic resonance (NMR) of protons (2, 3) in a static magnetic field B{sub 0}. An applied radiofrequency pulse causes the protons to precess about B{sub 0} at their Larmor frequency {nu}{sub 0} = ({gamma}/2{pi})B{sub 0}, where {gamma} is the gyromagnetic ratio; {gamma}/2{pi} = 42.58 MHz/tesla. The precessing protons generate an oscillating magnetic field and hence a voltage in a nearby coil that is amplified and recorded. The application of three-dimensional magnetic field gradients specifies a unique magnetic field and thus an NMR frequency in each voxel of the subject, so that with appropriate encoding of the signals one can acquire a complete image (4). Most clinical MRI systems involve magnetic fields generated by superconducting magnets, and the current trend is to higher magnetic fields than the widely used 1.5-T systems (5). Nonetheless, there is ongoing interest in the development of less expensive imagers operating at lower fields. Commercially available 0.2-T systems based on permanent magnets offer both lower cost and a more open access than their higher-field counterparts, at the expense of signal-to-noise-ratio (SNR) and spatial resolution. At the still lower field of 0.03 mT maintained by a conventional, room-temperature solenoid, Connolly and co-workers (6, 7) obtain good spatial resolution and signal-to-noise ratio (SNR) by prepolarizing the protons in a field B{sub p} of 0.3 T. Prepolarization (8) enhances the magnetic moment of an ensemble of protons over that produced by the lower precession field; after the polarizing field is removed, the higher magnetic moment produces a correspondingly larger signal during its precession in B{sub 0}. Using the same method, Stepisnik et al. (9) obtained MR images in the Earth's magnetic field ({approx} 50 {micro}T). Alternatively, one can enhance the signal 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.

  7. NEON Collaborative Data Collection Campaign at Pacific South West Site in California

    NASA Astrophysics Data System (ADS)

    Kampe, T. U.; Leisso, N.; Krause, K.; Musinsky, J.; Petroy, S. B.; Wasser, L. A.; Cawse-Nicholson, K.; van Aardt, J. A.; Schaaf, C.; Strahler, A. H.; Serbin, S. P.

    2013-12-01

    The National Ecological Observatory Network (NEON) is a continental-scale observatory that will collect biological, chemical and geophysical data over the continental United States in order to study biodiversity, landcover change, climate change and invasive species. In June 2013, a large-scale data collection took place over NEON's Pacific South West (PSW) site 17 in CA, USA. Data were collected in the San Joaquin Experimental Range and the Sierra National Forest. NEON's AOP (Airborne Observation Platform) acquired high spatial resolution hyperspectral data (~1m pixels), waveform lidar, discrete lidar, and RGB imagery over all three sites. A field team simultaneously collected atmospheric and vegetation inventory data, including tree locations, height, diameter-at-breast-height (DBH), species, and spectral data. The NEON collect was centered within a collaboration of multiple research entities, including NASA, Rochester Institute of Technology (RIT), University of Massachusetts (Boston; UMB, and Lowell; UML), Boston University (BU), and the University of Wisconsin, Madison (UWM). NASA's AVIRIS and MASTER sensors were flown over a wider area encompassing the NEON sites, with AVIRIS acquiring hyperspectral data (224 bands) at approximately 30m spatial resolution, and MASTER acquiring multispectral thermal data (50 bands) at approximately 50m spatial resolution. These data will be downscaled to approximate theoretical HyspIRI data (60m spatial resolution) as part of a large collection of preparatory research. Concurrently, a variety of university teams were active in the field: RIT collected ground-based lidar, leaf area index (LAI), herbaceous biomass measurements, wide-angle photographs, and spectral measurements. Data were collected over 20 80x80m sites, centered on existing 20x20m NEON sites. This data set will be used to inform synthetic scene design and to study the impact of sub-pixel structural variation on pixel-level spectral response; The BU, UMB, and UML team surveyed three sites in the Sierras with their terrestrial waveform lidar (DWEL) and collected Trac measurements of LAI, while UMB collected additional discrete ground-based lidar scans and additional forestry measures at San Joaquin and the Sierras; A team from the UWM collected leaf-level reflectance and transmission spectra and measured leaf-level gas exchange and chlorophyll fluorescence. This multifaceted collaboration, funded by the NSF NEON and NASA HyspIRI Preparatory Science programs, will support key scientific developments by combining the expertise from multiple sensing modalities. This experiment highlights the advantages of data and skills sharing in remote sensing applications. An overview of the larger effort and individual early science will be presented.

  8. 50 CFR 648.23 - Mackerel, squid, and butterfish gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... part of the top of the regulated portion of a trawl net. (ii) Jigging exemption. During closures of the... fishing for longfin squid using jigging gear are exempt from the closure possession limit specified...

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26459874

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

    PubMed

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

    2015-01-01

    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. PMID:26459874

  12. NEON: High Frequency Monitoring Network for Watershed-Scale Processes and Aquatic Ecology

    NASA Astrophysics Data System (ADS)

    Vance, J. M.; Fitzgerald, M.; Parker, S. M.; Roehm, C. L.; Goodman, K. J.; Bohall, C.; Utz, R.

    2014-12-01

    Networked high frequency hydrologic and water quality measurements needed to investigate physical and biogeochemical processes at the watershed scale and create robust models are limited and lacking standardization. Determining the drivers and mechanisms of ecological changes in aquatic systems in response to natural and anthropogenic pressures is challenging due to the large amounts of terrestrial, aquatic, atmospheric, biological, chemical, and physical data it requires at varied spatiotemporal scales. The National Ecological Observatory Network (NEON) is a continental-scale infrastructure project designed to provide data to address the impacts of climate change, land-use, and invasive species on ecosystem structure and function. Using a combination of standardized continuous in situ measurements and observational sampling, the NEON Aquatic array will produce over 200 data products across its spatially-distributed field sites for 30 years to facilitate spatiotemporal analysis of the drivers of ecosystem change. Three NEON sites in Alabama were chosen to address linkages between watershed-scale processes and ecosystem changes along an eco-hydrological gradient within the Tombigbee River Basin. The NEON Aquatic design, once deployed, will include continuous measurements of surface water physical, chemical, and biological parameters, groundwater level, temperature and conductivity and local meteorology. Observational sampling will include bathymetry, water chemistry and isotopes, and a suite of organismal sampling from microbes to macroinvertebrates to vertebrates. NEON deployed a buoy to measure the temperature profile of the Black Warrior River from July - November, 2013 to determine the spatiotemporal variability across the water column from a daily to seasonal scale. In July 2014 a series of water quality profiles were performed to assess the contribution of physical and biogeochemical drivers over a diurnal cycle. Additional river transects were performed across our site reach to capture the spatial variability of surface water parameters. Our preliminary data show differing response times to precipitation events and diurnal processes informing our infrastructure designs and sampling protocols aimed at providing data to address the eco-hydrological gradient.

  13. Aquatic Biogeochemical Prototype Activities at the National Ecological Observatory Network (NEON)

    NASA Astrophysics Data System (ADS)

    Goodman, K. J.; Powell, H.; Cilke, T.; Price, A.

    2010-12-01

    NEON is currently prototyping select data collections in order to develop robust protocols and procedures to be used across a gradient of stream systems, evaluating morphological mapping tools, and designing lightweight equipment and secure, stable, non-intrusive sensor installations. Here we present the status of the Aquatic prototype efforts that are occurring at the D15 Candidate Core Aquatic site: Red Butte Creek, Utah. Prototype activities include discharge and reaeration measurements, development of a stream reaeration rating curve, and water chemistry sampling. We are measuring reaeration, a measure of gas exchange across the air-water interface, using a continuous injection of SF6, an inert gas. In addition, Cl-, a conservative tracer, is added to the stream to account for dilution by groundwater inputs. As part of the NEON Prototype effort, we re-designed a lightweight, easy-to- use pump system for the addition of this conservative tracer during reaeration measurements. This pump, which costs a fraction of commercially available pumps, has performed well during field-testing and meets NEONs needs and requirements for the injection of the conservative tracer. The NEON prototype efforts will help ensure that the data collected across the Observatory, including the 36 aquatic sites across 19 ecoclimatic domains, will enable researchers to investigate and model ecosystems response to climate change and landuse change at multiple spatial and temporal scales. The Observatory will collect data from both in-situ sensors and field data collections to produce measurements using consistent and standardized procedures and protocols across the United States. During Observatory Operations, these data will be available to the public on the web in near-real time.

  14. Solar wind helium, neon, and argon in Genesis aluminum collectors

    NASA Astrophysics Data System (ADS)

    Mabry, Jennifer Christine

    2009-11-01

    The Sun contains over 99% of the mass of the solar system and so, to fully develop a model of how the solar system formed and evolved what the starting composition was and how it evolved, it is crucial to know the isotopic composition of the sun. The Genesis mission collected samples of solar wind (SW) for 853 days and returned them to Earth for analysis. Making these measurements on earth-based instruments is currently the only way to get sufficient precision to differentiate between different solar system components, and SW is the only source of solar material available for sampling. However, there are several processes that have the potential to significantly alter the composition between the time when SW ions are accelerated away from the sun, to the time the laboratory measurements are made. This work attempts to constrain these sources of fractionation and present the best estimate of the isotopic composition of SW helium, neon, and argon implanted into two different aluminum SW collectors on board the Genesis Mission, Al on sapphire and polished Al. First, during the collection phase of the Genesis mission, diffusion can alter the initial implantation profiles of the SW ions in the collector targets and cause losses of shallowly implanted species. These losses preferentially affect the lighter isotopes, which in turn means the measured ratios of the remaining reservoir will be heavier, both isotopically and elementally. I have conducted a diffusion experiment on a similar time scale as the Genesis mission to determine the diffusion parameters of the two different aluminum collector materials and to quantify the changes in the measured ratios due to diffusive losses for the light noble gases. The results of this experiment show that the polished Al collector is not sufficiently retentive of the light noble gases to be a reliable collector for the light gases, but that the composition of the light gases implanted in the Al on sapphire collector does not show a measurable effect due to thermal diffusion. Isotopic fractionation can also occur even before implantation of the SW ions, if the processes which accelerate the SW away from the sun are mass-dependent. In an effort to quantify this effect, the Genesis mission collected separate samples of different types ('regimes') of SW: low-speed, high-speed, and coronal mass ejections, in addition to collecting bulk SW. Compositional differences between the different SW regimes (especially the low-speed and high-speed SW) are thought to provide a measure of this fractionation. By making high-precision isotopic measurements on collectors of the three SW regimes, we have put strict upper limits on the difference between the low- speed and high-speed SW regimes: 20 Ne/ 22 Ne < 0.24 0.37% and 36 Ar/ 38 Ar < 0.11 0.26%. Both of these differences are less than 1s statistical errors. Helium isotopes are much more susceptible to modification which prevents us from putting a strict upper limit as for Ne and Ar. And finally we have made isotopic measurements of the light noble gases of the bulk SW (without selective collection of different SW regimes) from the aluminum collectors. Accounting for the sources of fractionation discussed above, I propose the following as the best current bulk SW isotopic values: 20 Ne/ 22 Ne = 13.75 0.02, 21 Ne/ 22 Ne = 0.0329 0.0002, and 36 Ar / 38 Ar = 5.501 0.005 (all errors are 1s).

  15. Foraging ecology and movement patterns of jumbo squid (Dosidicus gigas) in the California Current System

    NASA Astrophysics Data System (ADS)

    Field, John C.; Elliger, Carl; Baltz, Ken; Gillespie, Graham E.; Gilly, William F.; Ruiz-Cooley, R. I.; Pearse, Devon; Stewart, Julia S.; Matsubu, William; Walker, William A.

    2013-10-01

    From 2002 to 2010, the jumbo squid (Dosidicus gigas) has been regularly encountered in large numbers throughout the California Current System (CCS). This species, usually found in subtropical waters, could affect coastal pelagic ecosystems and fisheries as both predator and prey. Neither the abundance of jumbo squid nor the optimal ocean conditions in which they flourish are well known. To understand better the potential impacts of this species on both commercial fisheries and on food-web structure we collected nearly 900 specimens from waters of the CCS, covering over 20 of latitude, over a range of depths and seasons. We used demographic information (size, sex, and maturity state) and analyzed stomach contents using morphological and molecular methods to best understand the foraging ecology of this species in different habitats of the CCS. Squid were found to consume a broad array of prey. Prey in offshore waters generally reflected the forage base reported in previous studies (mainly mesopelagic fishes and squids), whereas in more coastal waters (shelf, shelf break and slope habitats) squid foraged on a much broader mix that included substantial numbers of coastal pelagic fishes (Pacific herring and northern anchovy, as well as osmerids and salmonids in northern waters) and groundfish (Pacific hake, several species of rockfish and flatfish). We propose a seasonal movement pattern, based on size and maturity distributions along with qualitative patterns of presence or absence, and discuss the relevance of both the movement and distribution of jumbo squid over space and time. We find that jumbo squid are a generalist predator, which feeds primarily on small, pelagic or mesopelagic micronekton but also on larger fishes when they are available. We also conclude that interactions with and potential impacts on ecosystems likely vary over space and time, in response to both seasonal movement patterns and highly variable year-to-year abundance of the squid themselves.

  16. Characterization of the bacterial diversity in Indo-West Pacific loliginid and sepiolid squid light organs.

    PubMed

    Guerrero-Ferreira, Ricardo; Gorman, Clayton; Chavez, Alba A; Willie, Shantell; Nishiguchi, Michele K

    2013-01-01

    Loliginid and sepiolid squid light organs are known to host a variety of bacterial species from the family Vibrionaceae, yet little is known about the species diversity and characteristics among different host squids. Here we present a broad-ranging molecular and physiological analysis of the bacteria colonizing light organs in loliginid and sepiolid squids from various field locations of the Indo-West Pacific (Australia and Thailand). Our PCR-RFLP analysis, physiological characterization, carbon utilization profiling, and electron microscopy data indicate that loliginid squid in the Indo-West Pacific carry a consortium of bacterial species from the families Vibrionaceae and Photobacteriaceae. This research also confirms our previous report of the presence of Vibrio harveyi as a member of the bacterial population colonizing light organs in loliginid squid. pyrH sequence data were used to confirm isolate identity, and indicates that Vibrio and Photobacterium comprise most of the light organ colonizers of squids from Australia, confirming previous reports for Australian loliginid and sepiolid squids. In addition, combined phylogenetic analysis of PCR-RFLP and 16S rDNA data from Australian and Thai isolates associated both Photobacterium and Vibrio clades with both loliginid and sepiolid strains, providing support that geographical origin does not correlate with their relatedness. These results indicate that both loliginid and sepiolid squids demonstrate symbiont specificity (Vibrionaceae), but their distribution is more likely due to environmental factors that are present during the infection process. This study adds significantly to the growing evidence for complex and dynamic associations in nature and highlights the importance of exploring symbiotic relationships in which non-virulent strains of pathogenic Vibrio species could establish associations with marine invertebrates. PMID:22885637

  17. Detection of Fatigue Damage Prior to Crack Initiation withScanning SQUID Microscopy

    SciTech Connect

    Lee, Tae-Kyu; Morris Jr., J.W.; Lee, Seungkyun; Clarke, John

    2005-11-07

    The remanence fields of fatigued ferritic steel specimens were measured using a scanning microscope based on a high transition temperature Superconducting Quantum Interference Device (SQUID). The results show an overall increase of remanence until dislocation density saturates and an additional local remanence increase after saturation during cyclic loading. Because of the combined magnetic and spatial resolution of the SQUID microscope, these local changes of dislocation structures can be detected before a crack actually initiates, and identify the sites where crack nucleation will occur.

  18. Trace metal levels in the raw and tinned squid Loligo patagonica.

    PubMed

    Falandysz, J

    1989-01-01

    The cadmium, silver, lead, copper, zinc, manganese, iron and mercury levels in the edible and inedible tissues of raw and tinned Loligo patagonica squid were determined using flame atomic absorption spectrometry (AAS) for Cd, Ag, Pb, Cu, Zn, Mn and Fe and cold-vapour AAS for Hg. The mean values obtained relative to the wet-weight (mg/kg) for the edible parts (skinless mantle, arms and crone and fin) of the raw and tinned (mantle) squid, and in whole raw and tinned squid, were: 0.32, 0.32, 0.31, 4.3, 3.2 and 3.0 for Cd, 1.0, 0.34, 0.77, 0.27, 0.59 and 0.44 for Pb, 7.8, 5.5, 11, 33, 22 and 26 for Cu, 12, 13, 12, 19, 16 and 17 for Zn, 0.38, 0.45, 0.48, 0.75, 0.48 and 0.73 for Mn and 2.7, 2.3, 3.4, 3.4, 2.2 and 9.4 for Fe, respectively. The content of silver and mercury in the mantle of the tinned squid were 0.18 and 0.012 mg/kg, respectively. As a consequence of whole squid processing, highly elevated levels of cadmium, and also somewhat higher levels of some of the other trace metals, were found in the edible parts of the tinned squid. The content of cadmium in the edible parts of the squid in all instances exceed, and for edible parts of the tinned whole squid considerably exceed, the proposed tolerance limit for cadmium in fishery products (0.05 mg/kg). PMID:2792467

  19. Characterization of the Bacterial Diversity in Indo-West Pacific Loliginid and Sepiolid Squid Light Organs

    PubMed Central

    Guerrero-Ferreira, Ricardo; Gorman, Clayton; Chavez, Alba A.; Willie, Shantell

    2013-01-01

    Loliginid and sepiolid squid light organs are known to host a variety of bacterial species from the family Vibrionaceae, yet little is known about the species diversity and characteristics among different host squids. Here we present a broad-ranging molecular and physiological analysis of the bacteria colonizing light organs in loliginid and sepiolid squids from various field locations of the Indo-West Pacific (Australia and Thailand). Our PCR-RFLP analysis, physiological characterization, carbon utilization profiling, and electron microscopy data indicate that loliginid squid in the Indo-West Pacific carry a consortium of bacterial species from the families Vibrionaceae and Photobacteriaceae. This research also confirms our previous report of the presence of Vibrio harveyi as a member of the bacterial population colonizing light organs in loliginid squid. pyrH sequence data were used to confirm isolate identity, and indicates that Vibrio and Photobacterium comprise most of the light organ colonizers of squids from Australia, confirming previous reports for Australian loliginid and sepiolid squids. In addition, combined phylogenetic analysis of PCR-RFLP and 16S rDNA data from Australian and Thai isolates associated both Photobacterium and Vibrio clades with both loliginid and sepiolid strains, providing support that geographical origin does not correlate with their relatedness. These results indicate that both loliginid and sepiolid squids demonstrate symbiont specificity (Vibrionaceae), but their distribution is more likely due to environmental factors that are present during the infection process. This study adds significantly to the growing evidence for complex and dynamic associations in nature and highlights the importance of exploring symbiotic relationships in which non-virulent strains of pathogenic Vibrio species could establish associations with marine invertebrates. PMID:22885637

  20. Molecular identification of anisakid nematodes third stage larvae isolated from common squid ( Todarodes pacificus) in Korea

    NASA Astrophysics Data System (ADS)

    Setyobudi, Eko; Jeon, Chan-Hyeok; Choi, Kwangho; Lee, Sung Il; Lee, Chung Il; Kim, Jeong-Ho

    2013-06-01

    The occurrence of Genus Anisakis nematode larvae in marine fishes and cephalopods is epidemiologically important because Anisakis simplex larval stage can cause a clinical disease in humans when infected hosts are consumed raw. Common squid ( Todarodes pacificus) from Korean waters were investigated for anisakid nematodes infection during 2009˜2011. In total, 1,556 larvae were collected from 615 common squids and 732 of them were subsequently identified by PCR-RFLP analysis of ITS rDNA. Depending on the sampling locations, the nematode larvae from common squid showed different prevalence, intensity and species distribution. A high prevalence (P) and mean intensity (MI) of infection were observed in the Yellow Sea (n = 250, P = 86.0%, MI = 5.99 larvae/host) and the southern sea of Korea (n = 126, P = 57.1%, MI = 3.36 larvae/host). Anisakis pegreffii was dominantly found in common squid from the southern sea (127/ 140, 90.7%) and the Yellow Sea (561/565, 98.9%). In contrast, the P and MI of infection were relatively low in the East Sea (n = 239, P = 8.37%, MI = 1.25 larvae/host). A. pegreffii was not found from the East Sea and 52.0% (13/25) of the nematodes were identified as A. simplex. Most of them were found in the body cavity or digestive tract of common squid, which are rarely consumed raw by humans. Considering the differenences in anisakid nematode species distribution and their microhabitat in common squid, it remains unclear whether common squid plays an important role in the epidemiology of human anisakis infection in Korea. Further extensive identification of anisakid nematodes in common squid, with geographical and seasonal information will be necessary.

  1. High-T(sub c) squid application in medicine and geophysics

    NASA Technical Reports Server (NTRS)

    Polushkin, V. N.; Uchaikin, S. V.; Vasiliev, B. V.

    1990-01-01

    In the Laboratory a high-T(sub c) one-hole squid was built from Y1Ba2Cu3O(7-x) ceramics obtained by a standard procedure of solid state reaction. The ceramics with critical current density J(sub c) is greater than 100 A/sq cm was selected. In the middle of 10 x 10 x 2 mm ceramics pellet a 0.8 mm hole was drilled in which superconducting loop of the squid was located. Between the hole and the edge of the pellet a cut was mechanically filed out with a bridge inside it connecting the superconducting ring. A scheme of the magnetometer is presented. The resonant frequency shift of the tank circuit, the connection of the squid with this circuit, and the squid inductance are evaluated. One of the most interesting fields of the squid-based magnetometer application is biomagnetism, particularly, the human heart magnetocardiogram measuring. The low-temperature squids were used in this area and many interesting and important scientific results have been obtained. The observations have shown that the main noise contribution was not due to the squid but to the Earth's magnetic field variations, industrial inductions, and mainly to the vibrations caused by liquid nitrogen boiling and by vibrations of the box. Further attempts are needed to reduce the magnetic noise inductions. Nevertheless, the estimations promise the maximum signal/noise relation of the high-T(sub c) squid-magnetocardiometer to be not less than 10:1 in a bandwidth of 60 Hz. Apparently, such resolution would be enough not only for steady cardiogram reading but even for thin structure investigation at average technique application.

  2. Gradiometer Using Middle Loops as Sensing Elements in a Low-Field SQUID MRI System

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin; Hahn, Inseob; Ho Eom, Byeong

    2009-01-01

    A new gradiometer scheme uses middle loops as sensing elements in lowfield superconducting quantum interference device (SQUID) magnetic resonance imaging (MRI). This design of a second order gradiometer increases its sensitivity and makes it more uniform, compared to the conventional side loop sensing scheme with a comparable matching SQUID. The space between the two middle loops becomes the imaging volume with the enclosing cryostat built accordingly.

  3. Pest Control on the "Fly"

    NASA Technical Reports Server (NTRS)

    2002-01-01

    FlyCracker(R), a non-toxic and environmentally safe pesticide, can be used to treat and control fly problems in closed environments such as milking sheds, cattle barns and hutches, equine stables, swine pens, poultry plants, food-packing plants, and even restaurants, as well as in some outdoor animal husbandry environments. The product can be applied safely in the presence of animals and humans, and was recently permitted for use on organic farms as livestock production aids. FlyCracker's carbohydrate technology kills fly larvae within 24 hours. By killing larvae before they reach the adult stages, FlyCracker eradicates another potential breeding population. Because the process is physical-not chemical-flies and other insects never develop resistance to the treatment, giving way to unlimited use of product, while still keeping the same powerful effect.

  4. A HTS dc SQUID-NMR: fabrication of the SQUID and application to low-field NMR for fruit quality detection

    NASA Astrophysics Data System (ADS)

    Isingizwe Nturambirwe, J. Frédéric; Perold, Willem J.; Opara, Linus U.

    2014-06-01

    Superconducting Quantum Interference Devices (SQUIDs) have made the detection of low-field (LF) and ultra-low field nuclear magnetic resonance (ULF-NMR) a reality. The latter has been proven to be a potential tool for non-destructive quality testing of horticultural products, amongst many other applications. High-Temperature Superconductor (HTS) dc SQUIDS are likely to allow for the development of not only low-cost NMR systems but also prototypes that are mobile and easily maintainable. A HTS dc SQUID was manufactured on an YBCO thin film, using a novel laser based lithography method. The lithography was implemented by a new laser system developed in-house, as a model of low-cost lithography systems. The junctions of the dc SQUID were tested and displayed normal I-V characteristics in the acceptable range for the application. In order to determine the viability of low-field NMR for non-destructive quality measurement of horticultural products, a commercial HTS dc SQUID-NMR system was used to measure quality parameters of banana during ripening. The trend of color change and sugar increase of the banana during ripening were the most highly correlated attributes to the SQUID-NMR measured parameter, average T1 (spin-lattice relaxation time). Further studies were done, that involved processing of the NMR signal into relaxation time resolved spectra. A spectral signature of banana was obtained, where each peak is a T1 value corresponding to a proton pool, and is reported here. These results will potentially lead to deeper understanding of the quality of the samples under study.

  5. Biodiversity among luminescent symbionts from squid of the genera Uroteuthis, Loliolus and Euprymna (Mollusca: Cephalopoda).

    PubMed

    Guerrero-Ferreira, R C; Nishiguchi, M K

    2007-10-01

    Luminescent bacteria in the family Vibrionaceae (Bacteria: ?-Proteobacteria) are commonly found in complex, bilobed light organs of sepiolid and loliginid squids. Although morphology of these organs in both families of squid is similar, the species of bacteria that inhabit each host has yet to be verified. We utilized sequences of 16S ribosomal RNA, luciferase ?-subunit (luxA) and the glyceraldehyde-3-phosphate dehydrogenase (gapA) genes to determine phylogenetic relationships between 63 strains of Vibrio bacteria, which included representatives from different environments as well as unidentified luminescent isolates from loliginid and sepiolid squid from Thailand. A combined phylogenetic analysis was used including biochemical data such as carbon use, growth and luminescence. Results demonstrated that certain symbiotic Thai isolates found in the same geographic area were included in a clade containing bacterial species phenotypically suitable to colonize light organs. Moreover, multiple strains isolated from a single squid host were identified as more than one bacteria species in our phylogeny. This research presents evidence of species of luminescent bacteria that have not been previously described as symbiotic strains colonizing light organs of Indo-West Pacific loliginid and sepiolid squids, and supports the hypothesis of a non-species-specific association between certain sepiolid and loliginid squids and marine luminescent bacteria. PMID:22707847

  6. Material properties of Pacific hake, Humboldt squid, and two species of myctophids in the California Current.

    PubMed

    Becker, Kaylyn N; Warren, Joseph D

    2015-05-01

    Material properties of the flesh from three fish species (Merluccius productus, Symbolophorus californiensis, and Diaphus theta), and several body parts of the Humboldt squid (Dosidicus gigas) collected from the California Current ecosystem were measured. The density contrast relative to seawater varied within and among taxa for fish flesh (0.9919-1.036), squid soft body parts (mantle, arms, tentacle, braincase, eyes; 1.009-1.057), and squid hard body parts (beak and pen; 1.085-1.459). Effects of animal length and environmental conditions on nekton density contrast were investigated. The sound speed contrast relative to seawater varied within and among taxa for fish flesh (0.986-1.027) and Humboldt squid mantle and braincase (0.937-1.028). Material properties in this study are similar to values from previous studies on species with similar life histories. In general, the sound speed and density of soft body parts of fish and squid were 1%-3% and 1%-6%, respectively, greater than the surrounding seawater. Hard parts of the squid were significantly more dense (6%-46%) than seawater. The material properties reported here can be used to improve target strength estimates from acoustic scattering models, which could increase the accuracy of biomass estimates from acoustic surveys for these nekton. PMID:25994685

  7. Making SQUIDs a practical tool for quantum detection and material characterization in the micro- and nanoscale

    NASA Astrophysics Data System (ADS)

    Schurig, Thomas

    2014-12-01

    The investigation of quantum effects and materials at low and ultra-low temperature often requires very sensitive measurements of weak magnetic signals, small electric currents or voltages. Superconducting Quantum Interference Devices (SQUIDs) have been proven as very attractive tools in this field. However, well established fabrication technology and readout techniques usually fail, particularly, when going to nanoscale magnetic detection where off- the-shelf devices can rarely be used. As an alternative to elaborate nanoSQUID technology, SQUID concepts for nanoscale magnetic detection which are employing conventional, and hence, reliable technology are discussed. Magnetic coupling of nano-sized samples to conventional SQUIDs, e.g. simple gradiometers or more complex devices as fully integrated susceptometers, can be improved significantly by integrating nanoscale detection loops into these devices. Furthermore, appropriate SQUID current sensors are a prerequisite for the readout of micro- and nanoSQUIDs and small-area detection coils. The conventionally made devices are intended for fabrication in moderate numbers to make them available for a broader community.

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

    PubMed

    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. PMID:26772407

  9. A Numerical Treatment of the Rf SQUID: I. General Properties andNoise Energy

    SciTech Connect

    Kleiner, Reinhold; Koelle, Dieter; Clarke, John

    2007-01-15

    We investigate the characteristics and noise performance of rf Superconducting Quantum Interference Devices (SQUIDs) by solving the corresponding Langevin equations numerically and optimizing the model parameters with respect to noise energy. After introducing the basic concepts of the numerical simulations, we give a detailed discussion of the performance of the SQUID as a function of all relevant parameters. The best performance is obtained in the crossover region between the dispersive and dissipative regimes, characterized by an inductance parameter {beta}{prime}{sub L} {triple_bond} 2{pi}LI{sub 0}/{Phi}{sub 0} {approx} 1; L is the loop inductance, I{sub 0} the critical current of the Josephson junction, and {phi}{sub 0} the flux quantum. In this regime, which is not well explored by previous analytical approaches, the lowest (intrinsic) values of noise energy are a factor of about 2 above previous estimates based on analytical approaches. However, several other analytical predictions, such as the inverse proportionality of the noise energy on the tank circuit quality factor and the square of the coupling coefficient between the tank circuit and the SQUID loop, could not be well reproduced. The optimized intrinsic noise energy of the rf SQUID is superior to that of the dc SQUID at all temperatures. Although for technologically achievable parameters this advantage shrinks, particularly at low thermal fluctuation levels, we give an example for realistic parameters that leads to a noise energy comparable to that of the dc SQUID even in this regime.

  10. Single SQUID multiplexer for arrays of voltage-biased superconducting bolometers

    SciTech Connect

    Yoon, Jongsoo; Clarke, John; Gildemeister, J.M.; Lee, Adrian T.; Myers, M.J.; Richards, P.L.; Skidmore, J.T.; Spieler, H.G.

    2001-08-20

    We describe a frequency domain superconducting quantum interference device (SQUID) multiplexer which monitors a row of low-temperature sensors simultaneously with a single SQUID. Each sensor is ac biased with a unique frequency and all the sensor currents are added in a superconducting summing loop. A single SQUID measures the current in the summing loop, and the individual signals are lock-in detected after the room temperature SQUID electronics. The current in the summing loop is nulled by feedback to eliminate direct crosstalk. In order to avoid the accumulation of Johnson noise in the summing loop, a tuned bandpass filter is inserted in series with each sensor. For a 32-channel multiplexer for Voltage-biased Superconducting Bolometer (VSB) with a time constant {approx}1msec, we estimate that bias frequencies in the range from {approx}500kHz to {approx}600kHz are practical. The major limitation of our multiplexing scheme is in the slew rate of a readout SQUID. We discuss a ''carrier nulling'' technique which could be used to increase the number of sensors in a row or to multiplex faster bolometers by reducing the required slew rate for a readout SQUID.

  11. Effect of voltage source internal resistance on the SQUID bootstrap circuit

    NASA Astrophysics Data System (ADS)

    Dong, Hui; Zhang, Guofeng; Wang, Yongliang; Zhang, Yi; Xie, Xiaoming; Krause, Hans-Joachim; Braginski, Alex I.; Offenhusser, Andreas

    2012-01-01

    The voltage-biased SQUID bootstrap circuit (SBC) is suitable for achieving simple and low-noise direct readout of dc SQUIDs. In practice, an ideal voltage bias is difficult to realize because of non-zero internal resistance Rin of the bias voltage source. In order to clearly observe the influence of Rin on the SBC parameters (namely the flux-to-current transfer coefficient (?I/??)SBC and the dynamic resistance Rd(SBC)) and the noise performance, we introduced an additional adjustable resistor Rad at room temperature to simulate a variable Rin between the SQUID and the preamplifier. We found that the measured SQUID flux noise does not rise, even though Rad increases significantly. This result demonstrates that a highly resistive connection can be inserted between the liquid-helium-cooled SQUID and the room-temperature readout electronics in the SBC scheme, thus reducing the conductive heat loss of the system. This work will be significant for developing multichannel SBC readout systems, e.g. for biomagnetism, and systems using SQUIDs as amplifiers, for example, in TES-array readout.

  12. Blood feeding behavior of the stable fly

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stable fly is a fly that looks similar to a house fly but both sexes are blood feeders. Blood is required for successful fertilization and development of eggs. Bites are painful but there is usually no pain after the fly stops feeding. The stable fly is a persistent feeder and will continue trying t...

  13. The FlyBar: Administering Alcohol to Flies

    PubMed Central

    van der Linde, Kim; Fumagalli, Emiliano; Roman, Gregg; Lyons, Lisa C.

    2014-01-01

    Fruit flies (Drosophila melanogaster) are an established model for both alcohol research and circadian biology. Recently, we showed that the circadian clock modulates alcohol sensitivity, but not the formation of tolerance. Here, we describe our protocol in detail. Alcohol is administered to the flies using the FlyBar. In this setup, saturated alcohol vapor is mixed with humidified air in set proportions, and administered to the flies in four tubes simultaneously. Flies are reared under standardized conditions in order to minimize variation between the replicates. Three-day old flies of different genotypes or treatments are used for the experiments, preferably by matching flies of two different time points (e.g., CT 5 and CT 17) making direct comparisons possible. During the experiment, flies are exposed for 1 hrto the pre-determined percentage of alcohol vapor and the number of flies that exhibit the Loss of Righting reflex (LoRR) or sedation are counted every 5 min. The data can be analyzed using three different statistical approaches. The first is to determine the time at which 50% of the flies have lost their righting reflex and use an Analysis of the Variance (ANOVA) to determine whether significant differences exist between time points. The second is to determine the percentage flies that show LoRR after a specified number of minutes, followed by an ANOVA analysis. The last method is to analyze the whole times series using multivariate statistics. The protocol can also be used for non-circadian experiments or comparisons between genotypes. PMID:24895004

  14. [Medical supply of long flies].

    PubMed

    Belevitin, A B; Tsygan, V N; Blagitin, A A; Lizogub, I N

    2010-05-01

    The article presents a characteristics of main negative factors, disimproving a functional condition and working capacity of airmen in long flies: long stay in a working pose, necessity of using of summer form, of defense form and oxygen-breath means, peculiarities of eating in fly, solving of nature-imposed necessity, relative sensor deprivation, sameliness of environment, high level of noise, hypokinesia, high nervous-emotional tension in conditions of air refueling, temperature fall, difference of barometric pressure, desynchronisms. Were given practical recommendations on maintenance of functional and working capacity of members of flying staff, realizing long flies. PMID:20698321

  15. Ameliorative effect of fly ashes

    SciTech Connect

    Bhumbla, D.K.

    1991-01-01

    Agronomic effectiveness and environmental impact of fly ashes used to reclaim pyritic acid mine spoils were investigated in the laboratory and field. Mine spoils at two abandoned sites were amended with three rates of fly ash, three rates of rock phosphate, and seeded with alfalfa and wheat. Application of fly ash decreased bulk density and increased moisture retention capacity of spoils. Fly ash application reduced cation exchange capacity, acidity, toxic levels of Al, Fe, and Mn in soils by buffering soil pH at 6.5, and retarded pyrite oxidation. The reduction in cation exchange capacity was compensated by release of plant nutrients through diffusion and dissolution of plerospheres in fly ash. Improvement of spoil physical, chemical and microbial properties resulted in higher yield, more nitrogen fixation, and utilization of P from rock phosphate by alfalfa. Laboratory investigations demonstrated that neutralization potential and the amounts of amorphous oxides of iron were more important for classifying fly ashes than the total elemental analysis presently used in a taxonomic classification system. Contamination of the food chain through plant removal of Mo and As in fly ash treated mine spoils was observed only for Mo and only for the first year of cropping. Plant available As and Mo decreased with time. Laboratory leaching and adsorption studies and a field experiment showed that trace metals do not leach from fly ashes at near neutral pH and more oxyanions will leach from fly ashes with low neutralization potential and low amounts of amorphous oxides of iron.

  16. Development of Magnetization Measurement Devices Using Micro-dc-SQUIDs and a Sr_2 RuO_4 Microplate

    NASA Astrophysics Data System (ADS)

    Nago, Y.; Shinozaki, T.; Tsuchiya, S.; Ishiguro, R.; Kashiwaya, H.; Kashiwaya, S.; Nomura, S.; Kono, K.; Takayanagi, H.; Maeno, Y.

    2016-02-01

    We developed high-sensitivity magnetization measurement devices composed of micro-dc-SQUIDs and a superconducting Sr_2 RuO_4 microplate, aiming to investigate novel magnetic properties related to a spin-triplet chiral p-wave superconductor with a mesoscopic size. Micron-sized dc-SQUID was fabricated by thin Al electrodes, and the SQUID structure was improved to prevent magnetic fluxes from intruding into SQUID electrodes. A Sr_2 RuO_4 superconducting microplate was fabricated into the size as small as the SQUID loop using a focused ion beam and directly mounted on the SQUID with precise positioning for high-sensitivity magnetization measurements. In the preliminary magnetization measurements of this device, we observed vortices trapped into the plate and thus the lower critical field. The improved magnetization measurement device developed to exclude undesirable flux intrusion successfully enabled high-sensitivity detection of quantized vortex.

  17. Flying wires at Fermilab

    SciTech Connect

    Gannon, J.; Crawford, C.; Finley, D.; Flora, R.; Groves, T.; MacPherson, M.

    1989-03-01

    Transverse beam profile measurement systems called ''Flying Wires'' have been installed and made operational in the Fermilab Main Ring and Tevatron accelerators. These devices are used routinely to measure the emittance of both protons and antiprotons throughout the fill process, and for emittance growth measurements during stores. In the Tevatron, the individual transverse profiles of six proton and six antiproton bunches are obtained simultaneously, with a single pass of the wire through the beam. Essential features of the hardware, software, and system operation are explained in the rest of the paper. 3 refs., 4 figs.

  18. Flying by Titan

    NASA Technical Reports Server (NTRS)

    Pelletier, Frederic J.; Antreasian, Peter G.; Ardalan, Shadan M.; Criddle, Kevin E.; Ionasescu, Rodica; Jacobson, Robert A.; Jones, Jeremy B.; Parcher, Daniel W.; Roth, Duane C.; Thompson, Paul F.; Vaughan, Andrew T.

    2008-01-01

    The Cassini spacecraft encounters the massive Titan about once every month. These encounters are essential to the mission as Titan is the only satellite of Saturn that can provide enough gravity assist to shape the orbit tour and allow outstanding science for many years. From a navigation point of view, these encounters provide many challenges, in particular those that fly close enough to the surface for the atmospheric drag to perturb the orbit. This paper discusses the dynamics models developed to successfully navigate Cassini and determine its trajectory. This includes the moon's gravity pull with its second degree zonal harmonics J2, the attitude thrust control perturbations and the acceleration of drag.

  19. Vision in flying insects.

    PubMed

    Egelhaaf, Martin; Kern, Roland

    2002-12-01

    Vision guides flight behaviour in numerous insects. Despite their small brain, insects easily outperform current man-made autonomous vehicles in many respects. Examples are the virtuosic chasing manoeuvres male flies perform as part of their mating behaviour and the ability of bees to assess, on the basis of visual motion cues, the distance travelled in a novel environment. Analyses at both the behavioural and neuronal levels are beginning to unveil reasons for such extraordinary capabilities of insects. One recipe for their success is the adaptation of visual information processing to the specific requirements of the behavioural tasks and to the specific spatiotemporal properties of the natural input. PMID:12490262

  20. Flying in, Flying out: Offshore Teaching in Higher Education

    ERIC Educational Resources Information Center

    Seah, Wee Tiong; Edwards, Julie

    2006-01-01

    This paper discusses the relatively new phenomenon of university education faculties offering offshore education. The analogy, "flying in, flying out" captures the intensity of such offshore experiences for visiting academics, and contrasts their professional experiences against expatriate academics. This paper reports on case studies of two

  1. A digital flux-locked loop for high temperature SQUID magnetometer and gradiometer systems with field cancellation

    SciTech Connect

    Kraus, R.H. Jr.; Bracht, R.; Flynn, E.R.

    1996-12-01

    The SQUID sensor is typically operated in a null detector mode where an analogue flux-locked-loop, FLL, provides a negative feedback to maintain linear operation. The modulated SQUID signal is amplified, filtered, demodulated, and integrated in the FLL. The resulting analog signal is a measure of the magnetic field and noise at the SQUID and is also fed back to the modulation and feedback (M & F) coil to null the flux at the SQUID to maintain the linear operating point. Thus, the FLL output signal is proportional to the change in magnetic field at the SQUID pickup coil, provided the slew rate and dynamic range of the SQUID and FLL system are not exceeded. The goal of the work is to advance technologies needed for a practical fieldable SQUID biomagnetic sensor. We used HTC SQUIDs to realize the benefits noted above. We also implemented the FLL algorithm on a digital-signal-processor (DSP) to realize a number of benefits including (1) software control of noise filtering and background rejection to enable unshielded use of SQUID sensors, (2) flux quanta countin and resetting SQUID operating point to increase system slew rate and dynamic range, (3) programmable FLL adaptable to numerous specific applications, (4) digital signal output (up to 32-bit precision), and (5) reduced FLL package cost. This paper presents results of external signal rejection for a sensor system using HTC SQUIDs, preamplifier circuit, and DSP FLL designed and built at our laboratory. We also note a companion paper in these proceedings and other references to the use of DSP in SQUID applications.

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

    DOEpatents

    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.

  3. NEON: Contributing continental-scale long-term environmental data for the benefit of society

    NASA Astrophysics Data System (ADS)

    Wee, B.; Aulenbach, S.

    2011-12-01

    The National Ecological Observatory Network (NEON) is a NSF funded national investment in physical and information infrastructure. Large-scale environmental changes pose challenges that straddle environmental, economic, and social boundaries. As we develop climate adaptation strategies at the Federal, state, local, and tribal levels, accessible and usable data are essential for implementing actions that are informed by the best available information. NEON's goal is to enable understanding and forecasting of the impacts of climate change, land use change and invasive species on continental-scale ecology by providing physical and information infrastructure. The NEON framework will take standardized, long-term, coordinated measurements of related environmental variables at each of its 62 sites across the nation. These observations, collected by automated instruments, field crews, and airborne instruments, will be processed into more than 700 data products that are provided freely over the web to support research, education, and environmental management. NEON is envisioned to be an integral component of an interoperable ecosystem of credible data and information sources. Other members of this information ecosystem include Federal, commercial, and non-profit entities. NEON is actively involved with the interoperability community via forums like the Foundation for Earth Science Information Partners and the USGS Community for Data Integration in a collective effort to identify the technical standards, best practices, and organizational principles that enable the emergence of such an information ecosystem. These forums have proven to be effective innovation engines for the experimentation of new techniques that evolve into emergent standards. These standards are, for the most part, discipline agnostic. It is becoming increasingly evident that we need to include socio-economic and public health data sources in interoperability initiatives, because the dynamics of coupled natural-human systems cannot be understood in the absence of data about the human dimension. Another essential element is the community of tool and platform developers who create the infrastructure for scientists, educators, resource managers, and policy analysts to discover, analyze, and collaborate on problems using the diverse data that are required to address emerging large-scale environmental challenges. These challenges are very unlikely to be problems confined to this generation: they are urgent, compelling, and long-term problems that require a sustained effort to generate and curate data and information from observations, models, and experiments. NEON's long-term national physical and information infrastructure for environmental observation is one of the cornerstones of a framework that transforms science and information for the benefit of society.

  4. Shattering the myth of the resonantly photo-pumped neon-like titanium laser

    SciTech Connect

    Nilsen, J.; MacGowan, B.J.; Da Silva, L.B.; Moreno, J.C.; Koch, J.A.

    1993-08-01

    Several years ago neon-like titanium (Z = 22) was made to lase at 326 {angstrom} on the 3p {yields} 3s (J = 0 {yields} 1) transition. At the time it was suggested that the lasing may be due to resonantly photo-pumping the neon-like titanium 2p {yields} 4d lines using 3s {yields} 2p and 3d {yields} 2p lines in carbon-like and nitrogen-like titanium which results in lasing on the 3p {yields} 3s transition in neon-like titanium. The strongest argument for this explanation was that adjacent elements (scandium and vanadium) did not lase while titanium was unique in having the above mentioned resonance. In addition a prepulse was required to make the titanium lase, suggestive of the formation of a low density plasma, and the plasma was very overstripped, so the above mentioned pump lines should be quite strong for photo-pumping. We have reinvestigated this laser system and will present results which show lasing on the 3p {yields} 3s (J = 0 {yields} 1) transition in neon-like chromium (Z = 24), iron (Z = 26), and nickel (Z = 28) at 285, 255, and 231 {angstrom} respectively. This destroys the myth of titanium being unique and makes highly unlikely that the previously mentioned photo-pumping mechanism is playing a significant role in the titanium laser. The chromium, iron, and nickel experiments all require a prepulse in order to lase and our calculations suggest that the prepulse is an exciting new way to create a uniform low density plasma when illuminating a thick slab target. This allows the proper conditions for gain and laser propagation for low Z neon-like ions and may also be applicable to other systems such as low Z nickel-like ions. We also will present experiments done on other low-Z materials and offer an explanation as to how the hyperfine effect is destroying the gain of neon-like ions with odd Z.

  5. Fly ash quality and utilization

    SciTech Connect

    Barta, L.E.; Lachner, L.; Wenzel, G.B.; Beer, M.J.

    1995-12-01

    The quality of fly ash is of considerable importance to fly ash utilizers. The fly ash puzzolanic activity is one of the most important properties that determines the role of fly ash as a binding agent in the cementing process. The puzzolanic activity, however is a function of fly ash particle size and chemical composition. These parameters are closely related to the process of fly ash formation in pulverized coal fired furnaces. In turn, it is essential to understand the transformation of mineral matter during coal combustion. Due to the particle-to-particle variation of coal properties and the random coalescence of mineral particles, the properties of fly ash particles e.g. size, SiO{sub 2} content, viscosity can change considerably from particle to particle. These variations can be described by the use of the probability theory. Since the mean values of these randomly changing parameters are not sufficient to describe the behavior of individual fly ash particles during the formation of concrete, therefore it is necessary to investigate the distribution of these variables. Examples of these variations were examined by the Computer Controlled Scanning Electron Microscopy (CCSEM) for particle size and chemical composition for Texas lignite and Eagel Butte mineral matter and fly ash. The effect of combustion on the variations of these properties for both the fly ash and mineral matter were studied by using a laminar flow reactor. It is shown in our paper, that there are significant variations (about 40-50% around the mean values) of the above-listed properties for both coal samples. By comparing the particle size and chemical composition distributions of the mineral matter and fly ash, it was possible to conclude that for the Texas lignite mineral matter, the combustion did not effect significantly the distribution of these properties, however, for the Eagel Butte coal the combustion had a major impact on these mineral matter parameters.

  6. Nitrogen, Neon and Argon Isotopes in Hypatia, a Diamond Bearing Pebble from the Lybien Desert Glass Strewnfield

    NASA Astrophysics Data System (ADS)

    Marty, B.; Zimmermann, L.; Meier, M. M.; Avice, G.; Kramers, J. D.; Andreoli, M. A. G.; Cartigny, P.; Wieler, R.

    2014-09-01

    We report nitrogen, neon and argon isotope data for Hypatia, a diamond-bearing pebble found in the southwestern part of Lybian desert glass strewnfield. We confirm its ET origin and discuss possible links with solar system reservoirs.

  7. Optical parameters of the tunable Bragg reflectors in squid

    PubMed Central

    Ghoshal, Amitabh; DeMartini, Daniel G.; Eck, Elizabeth; Morse, Daniel E.

    2013-01-01

    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 stackthe 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 system can be used as a model system to quantify the effects of various methods of tissue fixation. The microspectrophotometry technique described can be expected to provide deeper insights into the molecular and physical mechanisms governing other biophotonically active cells and structures. PMID:23740489

  8. Azadirachtin as a larvicide against the horn fly, stable fly, and house fly (Diptera: Muscidae).

    PubMed

    Miller, J A; Chamberlain, W F

    1989-10-01

    Effects of azadirachtin, a triterpenoid extracted from neem seed, Azadirachta indica A. Juss., were similar to those of insect growth regulators against the immature stages of the born fly, Haematobia irritans (L.), the stable fly, Stomoxys calcitrans (L.), and the house fly, Musca domestica L. When an ethanolic extract of ground seed was blended into cow manure, LC50 and LC90's for larval horn flies were 0.096 and 0.133 ppm azadirachtin, respectively. An emulsifiable concentrate (EC) had an LC50 for larval horn flies of 0.151 ppm and an LC90 of 0.268 ppm. For larval stable flies, the EC formulation had an LC50 of 7.7 ppm and an LC90 of 18.7 ppm azadirachtin in manure. Against larval house flies, the LC50 and LC90 were 10.5 and 20.2 ppm, respectively. When the EC formulation was administered orally to cattle at a rate of greater than or equal to 0.03 mg azadirachtin per kg of body weight per day or when ground neem seed was given as a daily supplement of greater than or equal to 10 mg seed per kg body weight, horn fly development in the manure was almost completely inhibited. In contrast, ground seed mixed in cattle feed at the rate of 100-400 mg seed per kg of body weight per day caused less than 50% inhibition of stable flies in the manure. PMID:2600264

  9. Spitzer Finds Cosmic Neon and Sulfur's Sweet Spot

    NASA Astrophysics Data System (ADS)

    Rubin, Robert

    Elemental abundances are the fossil remnants of the life history of a galaxy. Abundance ratios indicate the effects of star formation and the release of nuclear processed heavy elements via planetary nebulae and supernovae, plus other mechanisms. By deriving the elemental abundances and judicious modeling, astronomers are able to determine the relative importance of these processes in the chemical evolution of a galaxy. Modeling requires the input of nucleosynthetic yields from stellar evolution and supernova calculations. Since most fusion reaction rates cannot be measured in any earthly laboratory, the observed elemental ratios provide good tests of fusion reaction rate calculations. This proposal addresses the means by which we determine elemental abundances. H II regions are the prime laboratory for the measurement of the most abundant elements- He, C, N, O, Ne, S, and Ar, (usually with respect to hydrogen)- because these elements have strong lines in the ionization states produced by the Lyman continuum photons from massive O-stars. With Spitzer's Infrared Spectrograph (IRS) Short-High (SH) module (wavelength range 9.9-19.6 microns), we have the unique opportunity to measure lines from the two ions of neon (Ne+ & Ne++) and the two most abundant ions of sulfur (S++ & S+3) that are seen in H II regions: [Ne II] 12.8, [Ne III] 15.6, [S III] 18.7, and [S IV] 10.5 microns. These co-spatial/coeval spectra enable unprecedented accuracy for the measurement of these four lines and the estimate of the Ne/S abundance ratio. In Spitzer Cycles 1, 2, and 4 we measured respectively the Ne/S ratios for the galaxies M83 (a barred spiral), M33 (a local group spiral), and NGC 6822 (a local group dwarf irregular). With other GO programs, in Cycle 1 we measured the abundances in two Milky Way H II regions & the Arched Filaments in the Galactic Center, and in Cycle 5, the Orion Nebula. We propose to estimate the Ne and S abundances in many more H II regions, both extragalactic and Galactic, using archival Spitzer IRS-SH spectra. We wish to determine how much the true Ne/S ratio varies. There is a hint from our prior data that there is some metallicity dependence. We will also measure the abundances of other ions, including Si+, Fe+, and Fe++, for those sources that were also measured with the Spitzer IRS Long-High (LH) module (wavelength range 19-37 microns). The abundant elements Si and Fe are refractory and depleted onto dust grains; we will estimate the depletion from these gas-phase measurements. The LH also covers the [S III] 33.5 micron line that together with the 18.7 line provides a diagnostic of electron density. In addition to the nebular abundances, geometry, and density structure, photoionization models of H II region require input of an ionizing spectral energy distribution (SED) as predicted by stellar atmosphere models. Our four 'major' Spitzer program lines probe ions with ionization potentials 21.6 (Ne+), 41.0 (Ne++), 23.3 (S++), and 34.8 eV (S+3); thus, the ionic ratios derived from the observations are sensitive to this part of the ionizing SED, which often differs considerably between the stellar atmosphere models. In support of this project, Co-I Pauldrach will compute an extensive new set of O-star atmosphere models that use different metallicities than the Solar values used previously. This is a needed advance in order to do more refined comparisons between predictions and observation. The Spitzer-derived ionic ratios we have studied appear to provide a strong discriminant between the various state-of-the-art atmosphere models. Our work will help test/validate which set appears to be most realistic, and provide feedback to that community. Using the best SEDs provides the most reliable photoionization models for H II regions.

  10. Fly-back booster

    NASA Astrophysics Data System (ADS)

    Makino, Takashi

    1992-07-01

    An overview of the results of a quantitative evaluation with staging condition as parameters was conducted on a system composed of a fly-back booster model (methane engine plus jet engine equipped for return) and a elongated H-2 launch vehicle first-stage is presented as follows: (1) payload capacity of the model system is 28 tons (200 km low earth orbit); (2) 100 atm (ranging from 50 to 100 atm) is optimum for gas to gas methane engine combustion pressure; (3) the engine aperture ratio is 20; (4) re-entry aerodynamic heating rate is sufficiently within carbon to carbon composite material heat-resistance; and (5) maximum dynamic pressure is 10 kPa and maximum acceleration is 7G at re-entry. The overall system performance of a launch system with fly-back booster can be optimized by repetitively conducting the following procedures: (1) delta V distribution; (2) weight estimate; (3) aerodynamic characteristics estimate; (4) propulsion performance estimate; and (5) orbit analysis.

  11. Physics of flying

    NASA Astrophysics Data System (ADS)

    Vetrone, Jim

    2015-05-01

    Column editor's note: As the school year comes to a close, it is important to start thinking about next year. One area that you want to consider is field trips. Many institutions require that teachers plan for a field trip well in advance. Keeping that in mind, I asked Jim Vetrone to write an article about the fantastic field trip he takes his AP Physics students on. I had the awesome opportunity to attend a professional development day that Jim arranged at iFLY in the Chicago suburbs. The experience of "flying" in a wind tunnel was fabulous. Equally fun was watching the other physics teachers come up with experiments to have the professional "flyers" perform in the tube. I could envision my students being similarly excited about the experience and about the development of their own experiments. After I returned to school, I immediately began the process of trying to get this field trip approved for the 2015-16 school year. I suggest that you start your process as well if you hope to try a new field trip next year. The key to getting the approval, in my experience, is submitting a proposal early that includes supporting documentation from sources. Often I use NGSS or state standards as justifications for my field trips. I have also quoted College Board expectations for AP Physics 1 and 2 in my documents when requesting an unusual field trip.

  12. The Flying University

    NASA Astrophysics Data System (ADS)

    Friesen, Catherine

    The Flying University is solo theater performance framed as an academic lecture about Marie Curie and her discovery of radium, delivered to a group of women who have gathered in secret to further their education. As the lecture proceeds, the professor brings in her own research based on a study of Esther Horsch (1905-1991) who lived on a farm in central Illinois. She introduces data from Esther's journals, personal memories, and dreams about Esther's life. The professor's investigation of radium plays at the intersections of magical and mundane, decay and the transformation of life, and the place of ambition in these two women's lives. The intention of this piece is to explore these themes, which are full of mystery, through the traces of the daily lives of Mme. Curie and Esther. Their words and photos are used as roots from which to imagine the things that echo beyond their familiar work; elemental and also fantastically radiant. The Flying University was written and performed by Catherine Friesen April 27-29, 2012 in the Center for Performance Experiment at Hamilton College as part of the University of South Carolina MFA Acting Class of 2013 showcase, Pieces of Eight.

  13. Potential enhanced ability of giant squid to detect sperm whales is an exaptation tied to their large body size.

    PubMed

    Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Wainwright, Peter C

    2013-01-01

    It has been hypothesized that sperm whale predation is the driver of eye size evolution in giant squid. Given that the eyes of giant squid have the size expected for a squid this big, it is likely that any enhanced ability of giant squid to detect whales is an exaptation tied to their body size. Future studies should target the mechanism behind the evolution of large body size, not eye size. Reconstructions of the evolutionary history of selective regime, eye size, optical performance, and body size will improve the understanding of the evolution of large eyes in large ocean animals. PMID:24127991

  14. Mechanism study of high browning degree of mantle muscle meat from Japanese common squid Todarodes pacificus during air-drying.

    PubMed

    Geng, Jie-Ting; Kaido, Toshiki; Kasukawa, Masaru; Zhong, Chan; Sun, Le-Chang; Okazaki, Emiko; Osako, Kazufumi

    2015-06-01

    Mantle meat from the Japanese common squid (Todarodes pacificus) browns more than other squid meats during air-drying. The factors contributing to the browning of Japanese common squid, long-finned squid (Photololigo edulis) and bigfin reef squid (Sepioteuthis lessoniana) were studied in boiled and raw meat both before and after air-drying. Dried raw meat from the Japanese common squid browned more than dried boiled meat (b(∗) value, from 4.7 to 28.5). The results from SDS-PAGE showed significant degradation of myosin heavy chain (MHC) suggesting that protease activity in raw Japanese common squid meat was higher than in the other two species. The concentration of arginine (1932.0mg/100g) and ribose (28.8μmol/g) in Japanese common squid meat was higher than in the other two species. These results suggest that high protease activity and high concentrations of arginine and ribose increase the browning discoloration of Japanese common squid during air-drying. PMID:25624219

  15. Atlas of the Spectrum of a Platinum/Neon Hollow-Cathode Lamp in the Region 1130-4330 Å

    National Institute of Standards and Technology Data Gateway

    SRD 112 Atlas of the Spectrum of a Platinum/Neon Hollow-Cathode Lamp in the Region 1130-4330 Å (Web, free access)   Atlas of the Spectrum of a Platinum/Neon Hollow-Cathode Lamp in the Region 1130-4330 Å contains wavelengths and intensities for about 5600 lines in the region 4330 Å. An atlas plot of the spectrum is given, with the spectral lines marked and their intensities, wavelengths, and classifications listed.

  16. Passive Baited Sequential Fly Trap

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sampling fly populations associated with human populations is needed to understand diel behavior and to monitor population densities before and after control operations. Population control measures are dependent on the results of monitoring efforts as they may provide insight into the fly behavior ...

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

    NASA Astrophysics Data System (ADS)

    Hatsukade, Y.; Hayashi, K.; Shinyama, Y.; Kobayashi, Y.; Adachi, S.; Tanabe, K.; Tanaka, S.

    2011-11-01

    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 2Cu 3O 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.

  18. Effects of dietary shrimp, squid and octopus on serum and liver lipid levels in mice.

    PubMed

    Tanaka, K; Sakai, T; Ikeda, I; Imaizumi, K; Sugano, M

    1998-07-01

    The effects of three seafoods, shrimp, squid and octopus, on lipid metabolism were investigated in mice fed on 0.1% and 1.0% cholesterol-supplemented diets in the first experiment. One of each of these seafoods and casein were added to the basal diet at levels of 15% and 5%, respectively, as proteins. Casein served as the sole protein source of the control diet. The serum cholesterol concentration was significantly lower in the mice fed on shrimp and squid in the 0.1% cholesterol diet and on any seafood in the 1.0% cholesterol diet when compared with that in the mice fed on the control diet. The liver cholesterol concentration was significantly lower in all seafood groups given the 0.1% cholesterol diet, and in the squid and octopus groups given the 1.0% cholesterol diet. In the second experiment, the effect of these seafoods on lipid metabolism was compared with that of their defatted products in mice fed on a 0.2% cholesterol diet. Defatting resulted in an increase in the serum cholesterol and triglyceride levels in the shrimp and squid groups. The hepatic cholesterol concentration in all the seafood groups was significantly lower than that in the control group, and defatting did not influence the liver cholesterol concentration. Fecal total steroid excretion was higher in all the seafood groups when compared with that in the control group, and was not modified by the removal of fats. Thus, shrimp, squid and octopus exerted hypolipidemic activity; the serum cholesterol-lowering activity of shrimp and squid was attributed to their lipid fraction, whereas the non-lipid fraction of shrimp, squid and octopus contributed to a reduction of hepatic cholesterol and an increase of fecal steroid excretion. PMID:9720219

  19. Microtransplantation of cellular membranes from squid stellate ganglion reveals ionotropic GABA receptors.

    PubMed

    Conti, Luca; Limon, Agenor; Palma, Eleonora; Miledi, Ricardo

    2013-02-01

    The squid has been the most studied cephalopod, and it has served as a very useful model for investigating the events associated with nerve impulse generation and synaptic transmission. While the physiology of squid giant axons has been extensively studied, very little is known about the distribution and function of the neurotransmitters and receptors that mediate inhibitory transmission at the synapses. In this study we investigated whether ?-aminobutyric acid (GABA) activates neurotransmitter receptors in stellate ganglia membranes. To overcome the low abundance of GABA-like mRNAs in invertebrates and the low expression of GABA in cephalopods, we used a two-electrode voltage clamp technique to determine if Xenopus laevis oocytes injected with cell membranes from squid stellate ganglia responded to GABA. Using this method, membrane patches containing proteins and ion channels from the squid's stellate ganglion were incorporated into the surface of oocytes. We demonstrated that GABA activates membrane receptors in cellular membranes isolated from squid stellate ganglia. Using the same approach, we were able to record native glutamate-evoked currents. The squid's GABA receptors showed an EC(50) of 98 ?mol l(-1) to GABA and were inhibited by zinc (IC(50) = 356 ?mol l(-1)). Interestingly, GABA receptors from the squid were only partially blocked by bicuculline. These results indicate that the microtransplantation of native cell membranes is useful to identify and characterize scarce membrane proteins. Moreover, our data also support the role of GABA as an ionotropic neurotransmitter in cephalopods, acting through chloride-permeable membrane receptors. PMID:23493508

  20. Biology and control of tabanids, stable flies and horn flies.

    PubMed

    Foil, L D; Hogsette, J A

    1994-12-01

    Tabanids are among the most free-living adult flies which play a role as livestock pests. A single blood meal is used as a source of energy for egg production (100-1,000 eggs per meal), and females of certain species can oviposit before a blood meal is obtained (autogeny). Therefore, the maintenance of annual populations requires successful oviposition by only 2% of females. Wild animal blood sources are usually available to maintain annual tabanid populations. Larval habitats are also independent of domestic livestock. Thus, the use of repellents or partial repellents is the only effective chemical strategy to reduce the incidence of tabanids on livestock. Permanent traps (and possibly treated silhouette traps) can be employed to intercept flies. Selective grazing or confinement can also reduce the impact of tabanids. Stable fly adults are dependent on vertebrate blood for survival and reproduction, but the amount of time spent in contact with the host is relatively small. Stable fly larvae develop in manure, spilled feed and decaying vegetation. Management of larval habitats by sanitation is the key to stable fly control. Treatment of animals with residual insecticides can aid in control; thorough application to the lower body parts of livestock is important. Proper use of modified traps, using either treated targets or solar-powered electrocution grids, can be effective in reducing stable fly populations. Adult horn flies spend the major part of their time on the host, and the larvae are confined to bovid manure. Therefore, almost any form of topical insecticide application for livestock is effective against horn flies, in the absence of insecticide resistance. Treatments should be applied when economic benefit is possible; economic gains are associated with increased weaning weights and weight gains of yearling and growing cattle. Oral chemical treatments (insect growth regulators or insecticides) administered at appropriate rates via bolus, water, food or mineral mixtures can inhibit horn fly larval development. However, adult horn fly movement among cattle herds limits the use of larval control for horn fly population management. The augmentation of native parasites, predators and competitors has been attempted and even promoted for horn fly and stable fly control, but evidence for the success of such programmes is equivocal. PMID:7711307

  1. Using fly ash for construction

    SciTech Connect

    Valenti, M.

    1995-05-01

    Each year electrical utilities generate 80 million tons of fly ash, primarily from coal combustion. Typically, utilities dispose of fly ash by hauling it to landfills, but that is changing because of the increasing cost of landfilling, as well as environmental regulations. Now, the Electric Power Research Institute (EPRI), in Palo Alto, Calif., its member utilities, and manufacturers of building materials are finding ways of turning this energy byproduct into the building blocks of roads and structures by converting fly ash into construction materials. Some of these materials include concrete and autoclaved cellular concrete (ACC, also known as aerated concrete), flowable fill, and light-weight aggregate. EPRI is also exploring uses for fly ash other than in construction materials. One of the more high-end uses for the material is in metal matrix composites. In this application, fly ash is mixed with softer metals, such as aluminum and magnesium, to strengthen them, while retaining their lighter weight.

  2. Squid Pen Chitin Chitooligomers as Food Colorants Absorbers

    PubMed Central

    Liang, Tzu-Wen; Huang, Chih-Ting; Dzung, Nguyen Anh; Wang, San-Lang

    2015-01-01

    One of the most promising applications of chitosanase is the conversion of chitinous biowaste into bioactive chitooligomers (COS). TKU033 chitosanase was induced from squid pen powder (SPP)-containing Bacillus cereus TKU033 medium and purified by ammonium sulfate precipitation and column chromatography. The enzyme was relatively more thermostable in the presence of the substrate and had an activity of 93% at 50 °C in a pH 5 buffer solution for 60 min. Furthermore, the enzyme used for the COS preparation was also studied. The enzyme products revealed various mixtures of COS that with different degrees of polymerization (DP), ranging from three to nine. In the culture medium, the fermented SPP was recovered, and it displayed a better adsorption rate (up to 96%) for the disperse dyes than the water-soluble food colorants, Allura Red AC (R40) and Tartrazne (Y4). Fourier transform-infrared spectroscopic (FT-IR) analysis proved that the adsorption of the dyes onto fermented SPP was a physical adsorption. Results also showed that fermented SPP was a favorable adsorber and could be employed as low-cost alternative for dye removal in wastewater treatment. PMID:25608726

  3. Progress towards a metastable RF squid (MRFS) qubit

    NASA Astrophysics Data System (ADS)

    Kamal, Archana; Kerman, Andrew; Gustavsson, Simon; Jin, Xiaoyue; Yan, Fei; Gudmundsen, Ted; Hover, David; Sears, Adam; Yoder, Jonilyn; Orlando, Terry; Oliver, William

    2014-03-01

    The MRFS qubit [1] consists of an RF squid with a very high loop inductance, and whose two lowest quantum states are very well-defined, equal and opposite persistent supercurrents. These states can be strongly decoupled from each other, such that spontaneous electromagnetic decay processes of the excited state are extremely slow. Also, the large loop inductance suppresses the magnetic flux sensitivity of the design. We have realized these large inductances with NbN nanowires whose kinetic inductance is around 0.5 ?H. We will discuss experimental progress in measuring MRFS qubits fabricated using these inductors, and expected improvements in coherence. Future directions include studying the dynamics of quantum phase slips through these nanowires. [1] A. J. Kerman, PRL 104, 027002(2010). This research was funded in part by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA); and by the Asst Secretary of Defense for Research & Engineering under Air Force Contract number FA8721-05-C-0002. All statements of fact, opinion or conclusions contained herein are those of the authors and should not be construed as representing the official views or policies of IARPA, ODNI or the US government

  4. Light-dependent GTP-binding proteins in squid photoreceptors.

    PubMed Central

    Robinson, P R; Wood, S F; Szuts, E Z; Fein, A; Hamm, H E; Lisman, J E

    1990-01-01

    Previous biochemical and electrophysiological evidence suggests that in invertebrate photoreceptors, a GTP-binding protein (G-protein) mediates the actions of photoactivated rhodopsin in the initial stages of transduction. We find that squid photoreceptors contain more than one protein (molecular masses 38, 42 and 46 kDa) whose ADP-ribosylation by bacterial exotoxins is light-sensitive. Several lines of evidence suggest that these proteins represent distinct alpha subunits of G-proteins. (1) Pertussis toxin and cholera toxin react with distinct subsets of these polypeptides. (2) Only the 42 kDa protein immunoreacts with the monoclonal antibody 4A, raised against the alpha subunit of the G-protein of vertebrate rods [Hamm & Bownds (1984) J. Gen. Physiol. 84. 265-280]. (3) In terms of ADP-ribosylation, the 42 kDa protein is the least labile to freezing. (4) Of the 38 kDa and 42 kDa proteins, the former is preferentially extracted with hypo-osmotic solutions, as demonstrated by the solubility of its ADP-ribosylated state and by the solubility of the light-dependent binding of guanosine 5'-[gamma-thio]triphosphate. The specific target enzymes for the observed G-proteins have not been established. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:2124806

  5. Sodium channel permeation in squid axons. I: Reversal potential experiments.

    PubMed Central

    Begenisich, T B; Cahalan, M D

    1980-01-01

    1. Na channel reversal potentials were studied in perfused voltage clamped squid giant axons. The concentration dependence of ion selectivity was determined with both external and internal changes in Na and ammonium concentrations. 2. A tenfold change in the internal ammonium activity results in a 42 mV shift in the reversal potential, rather than the 56 mV shift expected from the Goldman, Hodgkin, Katz equation for a constant PNa/PNH4 ratio. However, changing [Na]o tenfold at constant internal [NH4] gives approximately the expected 56 mV shift. Therefore, the apparent channel selectivity depends upon the internal ammonium concentration but not the external Na concentration. 3. With ammonium outside and Na inside, the calculated permeability ratio is nearly constant, regardless of the permeant ion concentration. 4. Internal Cs ions can alter the Na/K permeability ratio. 5. The results are considered in terms of a three-barrier, two-site ionic permeation model. PMID:6259334

  6. Grayanotoxin opens Na channels from inside the squid axonal membrane.

    PubMed Central

    Seyama, I; Yamada, K; Kato, R; Masutani, T; Hamada, M

    1988-01-01

    External application of alpha-dihydro-grayanotoxin II (alpha-H2-GTX II) to squid giant axon under nonperfused condition caused substantial membrane depolarization. Intracellular perfusion of the fibers retarded this depolarization appreciably. Tritium-labeled alpha-dihydro-grayanotoxin II ([3H]alpha-H2-GTX II) in the external medium can permeate through the cell membrane, but permeation of alpha-H2-GTX II does not occur either with the carrier-mediated system or through the pores of the Na channel. The finding that the most hydrophilic grayanotoxin analogue, desacyl asebotoxin VII, is effective only when applied internally, strongly suggests that the receptor for grayanotoxin does not exist on the external surface of the membrane. The linear relationship between the concentration of [3H]alpha-H2-GTX II in the external medium and the count in the effluent from the perfused axon indicates that GTX II diffuses through the cell membrane's lipid phase and reaches the site of action only approached from the internal medium. PMID:2449919

  7. Metabolic efficiency with fast spiking in the squid axon

    PubMed Central

    Moujahid, Abdelmalik; d'Anjou, Alicia

    2012-01-01

    Fundamentally, action potentials in the squid axon are consequence of the entrance of sodium ions during the depolarization of the rising phase of the spike mediated by the outflow of potassium ions during the hyperpolarization of the falling phase. Perfect metabolic efficiency with a minimum charge needed for the change in voltage during the action potential would confine sodium entry to the rising phase and potassium efflux to the falling phase. However, because sodium channels remain open to a significant extent during the falling phase, a certain overlap of inward and outward currents is observed. In this work we investigate the impact of ion overlap on the number of the adenosine triphosphate (ATP) molecules and energy cost required per action potential as a function of the temperature in a HodgkinHuxley model. Based on a recent approach to computing the energy cost of neuronal action potential generation not based on ion counting, we show that increased firing frequencies induced by higher temperatures imply more efficient use of sodium entry, and then a decrease in the metabolic energy cost required to restore the concentration gradients after an action potential. Also, we determine values of sodium conductance at which the hydrolysis efficiency presents a clear minimum. PMID:23162461

  8. Squid pen chitin chitooligomers as food colorants absorbers.

    PubMed

    Liang, Tzu-Wen; Huang, Chih-Ting; Dzung, Nguyen Anh; Wang, San-Lang

    2015-01-01

    One of the most promising applications of chitosanase is the conversion of chitinous biowaste into bioactive chitooligomers (COS). TKU033 chitosanase was induced from squid pen powder (SPP)-containing Bacillus cereus TKU033 medium and purified by ammonium sulfate precipitation and column chromatography. The enzyme was relatively more thermostable in the presence of the substrate and had an activity of 93% at 50 C in a pH 5 buffer solution for 60 min. Furthermore, the enzyme used for the COS preparation was also studied. The enzyme products revealed various mixtures of COS that with different degrees of polymerization (DP), ranging from three to nine. In the culture medium, the fermented SPP was recovered, and it displayed a better adsorption rate (up to 96%) for the disperse dyes than the water-soluble food colorants, Allura Red AC (R40) and Tartrazne (Y4). Fourier transform-infrared spectroscopic (FT-IR) analysis proved that the adsorption of the dyes onto fermented SPP was a physical adsorption. Results also showed that fermented SPP was a favorable adsorber and could be employed as low-cost alternative for dye removal in wastewater treatment. PMID:25608726

  9. Optimization of the leak conductance in the squid giant axon.

    PubMed

    Seely, Jeffrey; Crotty, Patrick

    2010-08-01

    We report on a theoretical study showing that the leak conductance density, G{L} , in the squid giant axon appears to be optimal for the action potential firing frequency. More precisely, the standard assumption that the leak current is composed of chloride ions leads to the result that the experimental value for G{L} is very close to the optimal value in the Hodgkin-Huxley model, which minimizes the absolute refractory period of the action potential, thereby maximizing the maximum firing frequency under stimulation by sharp, brief input current spikes to one end of the axon. The measured value of G{L} also appears to be close to optimal for the frequency of repetitive firing caused by a constant current input to one end of the axon, especially when temperature variations are taken into account. If, by contrast, the leak current is assumed to be composed of separate voltage-independent sodium and potassium currents, then these optimizations are not observed. PMID:20866836

  10. Optimization of the R-SQUID noise thermometer

    SciTech Connect

    Seppae, H.

    1986-02-01

    The Josephson junction can be used to convert voltage into frequency and thus it can be used to convert voltage fluctuations generated by Johnson noise in a resistor into frequency fluctuations. As a consequence, the temperature of the resistor can be defined by measuring the variance of the frequency fluctuations. Unfortunately, the absolute determination of temperature by this approach is disturbed by several undesirable effects: a rolloff introduced by the bandwidth of the postdetection filter, additional noise caused by rf amplifiers, and a mixed noise effect caused by the nonlinearity of the Josephson junction together with rf noise in the tank circuit. Furthermore, the variance is a statistical quantity and therefore the limited number of frequency counts produces inaccuracy in a temperature measurement. In this work the total inaccuracy of the noise thermometer is analyzed and the optimal choice of the parameters is derived. A practical way to find the optimal conditions for the Josephson junction noise thermometer is discussed. The inspection shows that under the optimal conditions the total error is dependent only on the temperature under determination, the equivalent noise temperature of the preamplifier, the bias frequency of the SQUID, and the total time used for the measurement.

  11. An interchangeable scanning Hall probe/scanning SQUID microscope

    SciTech Connect

    Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin; Chen, Tse-Jun; Wang, M. J.; Ling, D. C.; Chi, C. C.; Chen, Jeng-Chung

    2014-08-15

    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.

  12. Thermal instabilities in micro-SQUIDs with long leads

    NASA Astrophysics Data System (ADS)

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Winkelmann, C. B.; Gupta, Anjan K.

    2015-03-01

    We report on Nb film based micron-size superconducting quantum interference devices (μ-SQUIDs) with long leads and with constrictions as weak-links (WLs). The current-voltage characteristics (IVCs) of these devices are hysteretic at low temperatures (T) with two re-trapping currents, Ir1 and Ir2, arising from thermal instabilities, and a critical-current (Ic) . We see oscillations with magnetic flux in Ic, but not in Ir1 and Ir2, in both the hysteretic and non-hysteretic regimes. We describe a one dimensional model for thermal instability in long-leads to understand re-trapping currents and its T-dependence. The critical-current shows a marked change in behaviour at the crossover temperature when it meets the lower re-trapping current and above this temperature the critical current subsists due to proximity superconductivity. The thermal stability with respect to phase-slips evolves with temperature and only above the crossover temperature the weak-link can cope with the heat generated by phase-slips giving a non-hysteretic behaviour. Keeping other device dimensions same the WLs' dimensions give a control on the hysteresis-free T-range. NK acknowledges the financial support from CSIR, India as well as CNRS-Institute Néel, Grenoble, France.

  13. Design study of steady-state 30-tesla liquid-neon-cooled magnet

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Brown, G. V.

    1976-01-01

    A design for a 30-tesla, liquid-neon-cooled magnet was reported which is capable of continuous operation. Cooled by nonboiling, forced-convection heat transfer to liquid neon flowing at 2.8 cu m/min in a closed, pressurized heat-transfer loop and structurally supported by a tapered structural ribbon, the tape-wound coils with a high-purity-aluminum conductor will produce over 30 teslas for 1 minute at 850 kilowatts. The magnet will have an inside diameter of 7.5 centimeters and an outside diameter of 54 centimeters. The minimum current density at design field will be 15.7 kA/sq cm.

  14. Sensing earth's rotation with a helium-neon ring laser operating at 1.15???m.

    PubMed

    Ulrich Schreiber, K; Thirkettle, Robert J; Hurst, Robert B; Follman, David; Cole, Garrett D; Aspelmeyer, Markus; Wells, Jon-Paul R

    2015-04-15

    We report on the operation of a 2.56??m2 helium-neon based ring laser interferometer at a wavelength of 1.152276?m using crystalline coated intracavity supermirrors. This work represents the first implementation of crystalline coatings in an active laser system and expands the core application area of these low-thermal-noise cavity end mirrors to inertial sensing systems. Stable gyroscopic behavior can only be obtained with the addition of helium to the gain medium as this quenches the 1.152502?m (2s4?2p7) transition of the neon doublet which otherwise gives rise to mode competition. For the first time at this wavelength, the ring laser is observed to readily unlock on the bias provided by the earth's rotation alone, yielding a Sagnac frequency of approximately 59Hz. PMID:25872053

  15. Up to fourth virial coefficients from simple and efficient internal-coordinate sampling: Application to neon

    NASA Astrophysics Data System (ADS)

    Wiebke, Jonas; Pahl, Elke; Schwerdtfeger, Peter

    2012-07-01

    A simple and efficient internal-coordinate importance sampling protocol for the Monte Carlo computation of (up to fourth-order) virial coefficients bar{B}_n of atomic systems is proposed. The key feature is a multivariate sampling distribution that mimics the product structure of the dominating pairwise-additive parts of the bar{B}_n. This scheme is shown to be competitive over routine numerical methods and, as a proof of principle, applied to neon: The second, third, and fourth virial coefficients of neon as well as equation-of-state data are computed from ab initio two- and three-body potentials; four-body contributions are found to be insignificant. Kirkwood-Wigner quantum corrections to first order are found to be crucial to the observed agreement with recent ab initio and experimental reference data sets but are likely inadequate at very low temperatures.

  16. The relative abundance of neon and magnesium in the solar corona

    NASA Technical Reports Server (NTRS)

    Rugge, H. R.; Walker, A. B. C., Jr.

    1976-01-01

    A technique is proposed for specifically determining the relative solar coronal abundance of neon and magnesium. The relative abundance is calculated directly from the relative intensity of the resonance lines of Ne X (12.134A) and Mg XI (9.169A) without the need for the development of a detailed model of the thermal structure of the corona. Moderate resolution Bragg crystal spectrometer results from the OVI-10 satellite were used to determine a coronal neon to magnesium relative abundance of 1.47 + or - 0.38. The application of this technique to a recent higher resolution rocket observation gave an abundance ratio of approximately 0.93 + or - 0.15.

  17. Reducing magnetic zero drift by optimizing proportions of neon dual isotopes in laser gyros

    NASA Astrophysics Data System (ADS)

    Di, Nan; Zhao, Jian-lin

    2012-03-01

    The relationships among the proportions of the neon dual isotopes ratio, scale factor corrections (SFCs), light intensities, environmental magnetic field and magnetic zero drift are discussed in detail by numerical simulations. The results show that the unification of the optimal operating point (OP) and the frequency stabilization operating point (FSP) is achievable by adjusting the proportions of neon dual isotopes accurately and tuning the cavity length with frequency stabilization system exactly. In that case, the left-rotation and right-rotation gyros can obtain the same SFC, which can decrease the magnetic sensitivity of the laser gyro efficiently. The Zeeman effect zero drift and the Faraday bias zero drift are both reduced by two orders of magnitude, while the magnetic shielding requirement of laser tube is decreased by 1-2 orders of magnitude.

  18. Collision-induced light scattering spectra and pair-polarizability trace and anisotropy of gaseous neon

    NASA Astrophysics Data System (ADS)

    El-Kader, M. S. A.

    2009-01-01

    New empirical pair-polarizability trace and anisotropy parameters, consistent with the spectroscopic measurements of neon gas at room temperature are obtained by fitting the calculated lineshapes and their first few even moments to the measured polarized and depolarized light scattering spectra. Good agreement with ab initio results in the literature is obtained and profiles calculated with these models are in excellent agreement with experiments.

  19. Resonances in Muon Transfer from Muonic Hydrogen to Oxygen and Neon

    NASA Astrophysics Data System (ADS)

    Tscherbul, T. V.; Lepetit, B.; Dupays, A.

    2006-06-01

    The influence of resonances on the muon transfer processes from muonic hydrogen to oxygen and neon (p?)1s + O8+ ? p + (?O) nl 7+ and (p?)1s + Ne10+ ? p + (?Ne)nl 9+ is considered using the Smith lifetime matrix formalism. It is shown that the existence of a long lived resonance in the case of Ne induces a stronger dependence on collision energy of the muon transfer cross-section for this system.

  20. Translating the Science of Measuring Ecosystems at a National Scale: Developing NEON's Online Learning Portal

    NASA Astrophysics Data System (ADS)

    Wasser, L. A.; Gram, W.; Goehring, L.

    2014-12-01

    "Big Data" are becoming increasingly common in many fields. The National Ecological Observatory Network (NEON) will be collecting data over the 30 years, using consistent, standardized methods across the United States. These freely available new data provide an opportunity for increased understanding of continental- and global scale processes such as changes in vegetation structure and condition, biodiversity and landuse. However, while "big data" are becoming more accessible and available, integrating big data into the university courses is challenging. New and potentially unfamiliar data types and associated processing methods, required to work with a growing diversity of available data, may warrant time and resources that present a barrier to classroom integration. Analysis of these big datasets may further present a challenge given large file sizes, and uncertainty regarding best methods to properly statistically summarize and analyze results. Finally, teaching resources, in the form of demonstrative illustrations, and other supporting media that might help teach key data concepts, take time to find and more time to develop. Available resources are often spread widely across multi-online spaces. This presentation will overview the development of NEON's collaborative University-focused online education portal. Portal content will include 1) videos and supporting graphics that explain key concepts related to NEON data products including collection methods, key metadata to consider and consideration of potential error and uncertainty surrounding data analysis; and 2) packaged "lab" activities that include supporting data to be used in an ecology, biology or earth science classroom. To facilitate broad use in classrooms, lab activities will take advantage of freely and commonly available processing tools, techniques and scripts. All NEON materials are being developed in collaboration with existing labs and organizations.

  1. Metastable and charged particle decay in neon afterglow studied by the breakdown time delay measurements

    SciTech Connect

    Markovic, V. Lj.; Gocic, S. R.; Stamenkovic, S. N.; Petrovic, Z. Lj.

    2007-10-15

    Memory effect--the long time variation of the electrical breakdown time delay on the relaxation time t{sub d}({tau}) in neon--was explained by the Ne({sup 3}P{sub 2}) (1s{sub 5}) metastable state remaining from the preceding glow [Dj. A. Bosan, M. K. Radovic, and Dj. M. Krmpotic, J. Phys. D 19, 2343 (1986)]. However, the authors neglected the quenching processes that reduce the effective lifetime of metastable states several orders of magnitude below that of the memory effect observations. In this paper the time delay measurements were carried out in neon at the pressure of 6.6 mbar in a gas tube with gold-plated copper cathode, and the approximate and exact numerical models are developed in order to study the metastable and charged particle decay in afterglow. It was found that the metastable hypothesis completely failed to explain the afterglow kinetics, which is governed by the decay of molecular neon ions and molecular nitrogen ions produced in Ne{sub 2}{sup +} collisions with nitrogen impurities; i.e., Ne{sub 2}{sup +}+N{sub 2}{yields}N{sub 2}{sup +}+2Ne. Charged particle decay is followed up to hundreds of milliseconds in afterglow, from ambipolar to the free diffusion limit. After that, the late afterglow kinetics in neon can be explained by the nitrogen atoms recombining on the cathode surface and providing secondary electrons that determine the breakdown time delay down to the cosmic rays and natural radioactivity level.

  2. Testing of a Neon Loop Heat Pipe for Large Area Cryocooling

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Robinson, Franklin Lee

    2014-01-01

    Cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks is required for future NASA missions. A cryogenic loop heat pipe (CLHP) can provide a closed-loop cooling system for this purpose and has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A neon CLHP was tested extensively in a thermal vacuum chamber using a cryopump as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components. Tests conducted included loop cool-down from the ambient temperature, startup, power cycle, heat removal capability, loop capillary limit and recovery from a dry-out, low power operation, and long duration steady state operation. The neon CLHP demonstrated robust operation. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by applying power to both the pump and evaporator without any pre-conditioning. It could adapt to changes in the pump power andor evaporator power, and reach a new steady state very quickly. The evaporator could remove heat loads between 0.25W and 4W. When the pump capillary limit was exceeded, the loop could resume its normal function by reducing the pump power. Steady state operations were demonstrated for up to 6 hours. The ability of the neon loop to cool large areas was therefore successfully verified.

  3. Calibration of liquid argon and neon detectors with {sup 83}Kr{sup m}

    SciTech Connect

    Lippincott, W. H.; Cahn, S. B.; Kastens, L. W.; McKinsey, D. N.; Nikkel, J. A.; Gastler, D.; Kearns, E.

    2010-04-15

    We report results from tests of {sup 83}Kr{sup m} as a calibration source in liquid argon and liquid neon. {sup 83}Kr{sup m} atoms are produced in the decay of {sup 83}Rb, and a clear {sup 83}Kr{sup m} scintillation peak at 41.5 keV appears in both liquids when filling our detector through zeolite coated with {sup 83}Rb. Based on this scintillation peak, we observe 6.0 photoelectrons/keV in liquid argon with a resolution of 8.2% (sigma/E) and 3.0 photoelectrons/keV in liquid neon with a resolution of 19% (sigma/E). The observed peak intensity subsequently decays with the {sup 83}Kr{sup m} half-life after stopping the fill, and we find evidence that the spatial location of {sup 83}Kr{sup m} atoms in the chamber can be resolved. {sup 83}Kr{sup m} will be a useful calibration source for liquid argon, neon dark matter, and solar neutrino detectors.

  4. Data Collection, Access and Presentation Technologies in the National Ecological Observatory (NEON) Design (Invited)

    NASA Astrophysics Data System (ADS)

    Aulenbach, S. M.; Berukoff, S. J.

    2010-12-01

    The National Ecological Observatory Network (NEON) will collect data across the United States on the impacts of climate change, land use change and invasive species on ecosystem functions and biodiversity. In-situ sampling and distributed sensor networks, linked by an advanced cyberinfrastructure, will collect site-based data on a variety of organisms, soils, aquatic systems, atmosphere and climate. Targeted airborne remote sensing observations made by NEON as well as geographical data sets and satellite resources produced by Federal agencies will provide data at regional and national scales. The resulting data streams, collected over a 30-year period, will be synthesized into fully traceable information products that are freely and openly accessible to all users. We provide an overview of several collection, access and presentation technologies evaluated for use by observatory systems throughout the data product life cycle. Specifically, we discuss smart phone applications for citizen scientists as well as the use of handheld devices for sample collection and reporting from the field. Protocols for storing, queuing, and retrieving data from observatory sites located throughout the nation are highlighted as are the application of standards throughout the pipelined production of data products. We discuss the automated incorporation of provenance information and digital object identifiers for published data products. The use of widgets and personalized user portals for the discovery and dissemination of NEON data products are also presented.

  5. PRESOLAR GRAINS FROM NOVAE: EVIDENCE FROM NEON AND HELIUM ISOTOPES IN COMET DUST COLLECTIONS

    SciTech Connect

    Pepin, Robert O.; Palma, Russell L.; Gehrz, Robert D.; Starrfield, Sumner

    2011-12-01

    Presolar grains in meteorites and interplanetary dust particles carry non-solar isotopic signatures pointing to origins in supernovae, giant stars, and possibly other stellar sources. There have been suggestions that some of these grains condensed in the ejecta of classical nova outbursts, but the evidence is ambiguous. We report neon and helium compositions in particles captured on stratospheric collectors flown to sample materials from comets 26P/Grigg-Skjellerup and 55P/Tempel-Tuttle that point to condensation of their gas carriers in the ejecta of a neon (ONe) nova. The absence of detectable {sup 3}He in these particles indicates space exposure to solar wind irradiation of a few decades at most, consistent with origins in cometary dust streams. Measured {sup 4}He/{sup 20}Ne, {sup 20}Ne/{sup 22}Ne, {sup 21}Ne/{sup 22}Ne, and {sup 20}Ne/{sup 21}Ne isotope ratios, and a low upper limit on {sup 3}He/{sup 4}He, are in accord with calculations of nucleosynthesis in neon nova outbursts. Of these, the uniquely low {sup 4}He/{sup 20}Ne and high {sup 20}Ne/{sup 22}Ne ratios are the most diagnostic, reflecting the large predicted {sup 20}Ne abundances in the ejecta of such novae. The correspondence of measured Ne and He compositions in cometary matter with theoretical predictions is evidence for the presence of presolar grains from novae in the early solar system.

  6. Focused helium and neon ion beam induced etching for advance EUV lithography and mask repair

    NASA Astrophysics Data System (ADS)

    Timilsina, Rajendra; Gongalez, Carlos; Rack, Philip

    2014-03-01

    The gas field ion microscope was used to investigate helium and neon ion beam induced etching (IBIE) of nickel as a candidate technique for extreme ultraviolet (EUV) lithography mask editing. No discernable nickel etching was observed for room temperature helium exposures at 16 and 30 keV in the range of 1x1015-1x1018 He+/cm2, however transmission electron microscopy (TEM) revealed subsurface damage to the underlying Mo-Si multilayer EUV mirror. Subsequently, neon beam induced etching at 30 keV was investigated over a similar dose range and successfully removed the entire 50 nm nickel top absorber film at a dose of approximately 3x1017 Ne+/cm2. TEM also revealed subsurface damage in the underlying Mo-Si multilayer. To further understand the helium and neon damage, we simulated the ion-solid interactions with our EnvizION Monte Carlo sputtering program which reasonably correlated the observed damage and bubble formation to the nuclear energy loss and the implanted inert gas concentration, respectively. A critical nuclear energy density loss of approximately 80 eV/nm3 and critical implant concentration of approximately 1020 atoms/cm3 have been calculated for damage generation in the multilayer structure.

  7. Investigation of compression of puffing neon by deuterium current and plasma sheath in plasma focus discharge

    NASA Astrophysics Data System (ADS)

    Kubes, P.; Paduch, M.; Cikhardt, J.; Cikhardtova, B.; Rezac, K.; Klir, D.; Kravarik, J.; Kortanek, J.; Zielinska, E.

    2015-06-01

    This paper presents the results of the research of the influence of compressed neon, injected by the gas-puff nozzle in front of the anode axis by the deuterium current and plasma sheath on the evolution of the pinch, and neutron production at the current of 2 MA. The intense soft X-ray emission shows the presence of neon in the central region of the pinch. During the implosion and stopping of the plasma sheath, the deuterium plasma penetrates into the internal neon layer. The total neutron yield of 1010-1011 has a similar level as in the pure deuterium shots. The neutron and hard X-ray pulses from fusion D-D reaction are as well emitted both in the phase of the stopping implosion and during the evolution of instabilities at the transformation of plasmoidal structures and constrictions composed in this configuration from both gases. The fast deuterons can be accelerated at the decay of magnetic field of the current filaments in these structures.

  8. Presolar Grains from Novae: Evidence from Neon and Helium Isotopes in Comet Dust Collections

    NASA Astrophysics Data System (ADS)

    Pepin, Robert O.; Palma, Russell L.; Gehrz, Robert D.; Starrfield, Sumner

    2011-12-01

    Presolar grains in meteorites and interplanetary dust particles carry non-solar isotopic signatures pointing to origins in supernovae, giant stars, and possibly other stellar sources. There have been suggestions that some of these grains condensed in the ejecta of classical nova outbursts, but the evidence is ambiguous. We report neon and helium compositions in particles captured on stratospheric collectors flown to sample materials from comets 26P/Grigg-Skjellerup and 55P/Tempel-Tuttle that point to condensation of their gas carriers in the ejecta of a neon (ONe) nova. The absence of detectable 3He in these particles indicates space exposure to solar wind irradiation of a few decades at most, consistent with origins in cometary dust streams. Measured 4He/20Ne, 20Ne/22Ne, 21Ne/22Ne, and 20Ne/21Ne isotope ratios, and a low upper limit on 3He/4He, are in accord with calculations of nucleosynthesis in neon nova outbursts. Of these, the uniquely low 4He/20Ne and high 20Ne/22Ne ratios are the most diagnostic, reflecting the large predicted 20Ne abundances in the ejecta of such novae. The correspondence of measured Ne and He compositions in cometary matter with theoretical predictions is evidence for the presence of presolar grains from novae in the early solar system.

  9. Investigation of compression of puffing neon by deuterium current and plasma sheath in plasma focus discharge

    SciTech Connect

    Kubes, P.; Cikhardt, J.; Cikhardtova, B.; Rezac, K.; Klir, D.; Kravarik, J.; Kortanek, J.; Paduch, M.; Zielinska, E.

    2015-06-15

    This paper presents the results of the research of the influence of compressed neon, injected by the gas-puff nozzle in front of the anode axis by the deuterium current and plasma sheath on the evolution of the pinch, and neutron production at the current of 2 MA. The intense soft X-ray emission shows the presence of neon in the central region of the pinch. During the implosion and stopping of the plasma sheath, the deuterium plasma penetrates into the internal neon layer. The total neutron yield of 10{sup 10}–10{sup 11} has a similar level as in the pure deuterium shots. The neutron and hard X-ray pulses from fusion D-D reaction are as well emitted both in the phase of the stopping implosion and during the evolution of instabilities at the transformation of plasmoidal structures and constrictions composed in this configuration from both gases. The fast deuterons can be accelerated at the decay of magnetic field of the current filaments in these structures.

  10. Comprehensive Study of Neon HXR and SXR Emitted from APF Plasma Focus Device

    NASA Astrophysics Data System (ADS)

    Baghdadi, R.; Etaati, G. R.; Habibi, M.; Amrollahi, R.; Roomi, A.

    2011-12-01

    Experimental results related to HXR and SXR properties of Neon plasma on the APF plasma focus device is presented. The experiments were carried on over a wide range of neon pressure and at voltages 11, 12 and 13 kV using plastic scintillator (NE102A) coupled with high gain PMT and six filtered photo PIN diodes. For the charging voltages of 11-13 kV with 2.17-3.04 kJ stored energy, the optimum operating pressure in neon is found to be in the range of 3.5-5 torr and the highest HXR emission was observed in the pressure of 5 torr at the voltage 13 kV and the maximum average HXR production is (9.84 ± 0.59) ×10-7 volt sec. The behavior of SXR intensities were registered by different filters and it was found out that Al-Mylar 6 μm and Cu 10 μm has the highest and lowest amount of X-ray transmission.

  11. The flying radiation case

    SciTech Connect

    Brownell, J.H.; Bowers, R.L.

    1997-04-01

    The Los Alamos foil implosion program has the goal of producing an intense, high-energy density x-ray source by converting the energy of a magnetically imploded plasma into radiation and material energy. One of the methods for converting the plasma energy into thermal energy and radiation and utilizing it for experiments is called the flying radiation case (FRC). In this paper the authors shall model the FRC and provide a physical description of the processes involved. An analytic model of a planar FRC in the hydrodynamic approximation is used to describe the assembly and shock heating of a central cushion by a conducting liner driver. The results are also used to benchmark a hydrodynamics code for modeling an FRC. They then use a radiation-hydrodynamics computational model to explore the effects of radiation production and transport when a gold plasma assembles on a CH cushion. Results are presented for the structure and evolution of the radiation hohlraum.

  12. Quality changes in squid (Loligo duvaucelli) tubes chilled with dry ice and water ice.

    PubMed

    Jeyasekaran, G; Jeya Shakila, R; Sukumar, D; Ganesan, P; Anandaraj, R

    2010-08-01

    Squid tubes were packed with 100% (w/w of squid) dry ice (PI), 20% dry ice and 50% water ice (PII) and 50% water ice (PIII) in polyethylene bags and store in thermocole boxes at room temperature (32 ± 2°C) for 24 h. Quality changes curing storage were studied. Lowest temperature of -30.3°C was attained in PI while it was 15-16°C in PII and PIII at 1 h of storage. The gas compositions in packages initially were 21% O2, 0.4% CO2 and 78.1% N2 in PI, PII and PIII, respectively. During storage for 24 h highest level of 82.5% CO2 was noticed in PII. Fresh squid tubes had bacterial flora of Hafnia, Pseudomonas, Bacillus, Flavobacterium and Alcaligens. Hafnia constituted 74% of the flora. Alcaligenes (47%), Alteromonas (30%) and Alcaligenes (56%) were dominant in squid tubes stored in 100% dry ice, in the combination package, and in 100% water ice, respectively. Increase in total volatile base nitrogen and trimethylamine nitrogen, no definite trend in free fatty acid values in all packages while increase in pH in PI and PIII and no consistent changes in PI were noticed during storage for 24 h. The PI had lowest bacterial counts and PIII the highest. Squids stored in PI and PII were sensorily acceptable after 24 and 18 h, respectively. PMID:23572660

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

    NASA Astrophysics Data System (ADS)

    Granata, C.; Vettoliere, A.; Walke, P.; Esposito, E.; Nappi, C.; Silvestrini, P.; Ruggiero, B.; Russo, M.

    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 ??0/Hz1/2 corresponding to a spin sensitivity in unit of Bohr magneton of 60 spin/Hz1/2. 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?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.

  14. Microbial experimental evolution as a novel research approach in the Vibrionaceae and squid-Vibrio symbiosis

    PubMed Central

    Soto, William; Nishiguchi, Michele K.

    2014-01-01

    The Vibrionaceae are a genetically and metabolically diverse family living in aquatic habitats with a great propensity toward developing interactions with eukaryotic microbial and multicellular hosts (as either commensals, pathogens, and mutualists). The Vibrionaceae frequently possess a life history cycle where bacteria are attached to a host in one phase and then another where they are free from their host as either part of the bacterioplankton or adhered to solid substrates such as marine sediment, riverbeds, lakebeds, or floating particulate debris. These two stages in their life history exert quite distinct and separate selection pressures. When bound to solid substrates or to host cells, the Vibrionaceae can also exist as complex biofilms. The association between bioluminescent Vibrio spp. and sepiolid squids (Cephalopoda: Sepiolidae) is an experimentally tractable model to study bacteria and animal host interactions, since the symbionts and squid hosts can be maintained in the laboratory independently of one another. The bacteria can be grown in pure culture and the squid hosts raised gnotobiotically with sterile light organs. The partnership between free-living Vibrio symbionts and axenic squid hatchlings emerging from eggs must be renewed every generation of the cephalopod host. Thus, symbiotic bacteria and animal host can each be studied alone and together in union. Despite virtues provided by the Vibrionaceae and sepiolid squid-Vibrio symbiosis, these assets to evolutionary biology have yet to be fully utilized for microbial experimental evolution. Experimental evolution studies already completed are reviewed, along with exploratory topics for future study. PMID:25538686

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

    NASA Astrophysics Data System (ADS)

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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

    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 Earths field and robot arms 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 ?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.

  17. Closed-cycle cryocooled SQUID system with superconductive shield for biomagnetism

    NASA Astrophysics Data System (ADS)

    Yu, Kwon Kyu; Lee, Yong Ho; Lee, Seong Joo; Shim, Jeong Hyun; Hwang, Seong min; Kim, Jin Mok; Kwon, Hyuckchan; Kim, Kiwoong

    2014-10-01

    We developed a cryocooled SQUID system with which human magnetocardiogram (MCG) and possibly magnetoenceparogram (MEG) can be measured. To reduce cyclic magnetic noises originating from the regenerator of the cold heads of the cryocooler, a superconductive shield (99.5% Pb) was used to protect the SQUID sensors, and a ferromagnetic shield (78% Ni alloy) was used to screen the cold head. In addition, the SQUID sensors chamber was placed at a distance of 1.8 m from the cold head chamber to install the cold-head chamber outside the magnetically shielded room (MSR) for future development. The loss in cooling power due to the increased distance was compensated by increasing the number of thermal rods, and thus the SQUID sensor and superconductive shield could be refrigerated to 4.8 K and 5 K, respectively. The superconductive shield successfully rejected thermal noise emitted from metallic blocks used to improve thermal conduction. The noise of the SQUID system was 3 fT/Hz1/2, and the cyclic magnetic noise could be reduced to 1.7 pT. We could obtain a clear MCG signal while the entire cryogenics was in operation without any special digital processing.

  18. Dc SQUID based on a three-band superconductor with broken time-reversal symmetry

    NASA Astrophysics Data System (ADS)

    Yerin, Y. S.; Omelyanchouk, A. N.; Il'ichev, E.

    2015-09-01

    The behavior of a dc superconducting quantum interference device (SQUID), based on dirty-point contacts between a single-band and three-band superconductor with broken time-reversal symmetry, is investigated. Using previously obtained results for Josephson effects in such systems, new features in characteristics of a dc SQUID are revealed. It is shown that in the case of a BTRS (broken time-reversal symmetry) three-band superconductor for the applied external magnetic flux, which is divisible by the half-integer flux, strong degeneracy of ground states of a dc SQUID has taken place. This can lead to the appearance of possible multi-hysteresis loops on a dependence of a total flux in the dc SQUID from the externally applied flux. The number of these loops depends on the position of ground states of a three-band superconductor. Also it is found that dependencies of a critical current on applied magnetic flux can have complicated multi-periodic forms, which differ from strictly periodic characteristics for conventional dc SQUIDs and Fraunhofer patterns for Josephson contacts in the external magnetic field.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Metal and metalloid concentrations in the giant squid Architeuthis dux from Iberian waters.

    PubMed

    Bustamante, P; Gonzlez, A F; Rocha, F; Miramand, P; Guerra, A

    2008-08-01

    This study investigated 14 trace elements (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn) in the tissues of the giant squid Architeuthis dux from the Mediterranean and Atlantic Spanish waters. As for other families of cephalopods, the digestive gland and the branchial hearts of Architeuthis showed the highest concentrations of Ag, Cd, Co, Cu, Fe, Ni, Se, V and Zn, highlighting their major role in the bioaccumulation and detoxification processes. With the exception of Hg, the muscles showed relatively low trace element concentrations. Nevertheless, this tissue contained the main proportion of the total As, Cr, Hg, Mn, Ni, and Zn body burden because muscles represent the main proportion of the squid mass. These findings suggest that the metal metabolism is overall the same as other cephalopod families from neritic waters. In females, Zn concentrations increased in the digestive gland with the squid's weight likely reflecting physiological changes during sexual maturation. Comparing the trace element concentrations in the tissues of Architeuthis, higher Ag, Cu, Hg and Zn concentrations in the squid from the Mediterranean reflected different exposure conditions. In comparison to other meso-pelagic squids from the Bay of Biscay, Cd concentrations recorded in the digestive gland suggest that Architeuthis might feed on more contaminated prey or that it displays a longer life span that other cephalopods. PMID:18514304

  1. Developing a Scalable Remote Sampling Design for the NEON Airborne Observation Platform (AOP)

    NASA Astrophysics Data System (ADS)

    Musinsky, J.; Wasser, L. A.; Kampe, T. U.; Leisso, N.; Krause, K.; Petroy, S. B.; Cawse-Nicholson, K.; van Aardt, J. A.; Serbin, S.

    2013-12-01

    The National Ecological Observatory Network (NEON) airborne observation platform (AOP) will collect co-registered high-resolution hyperspectral imagery, discrete and waveform LiDAR, and high-resolution digital photography for more than 60 terrestrial and 23 aquatic sites spread across the continental United States, Puerto Rico, Alaska and Hawaii on an annual basis over the next 30 years. These data, to be made freely available to the public, will facilitate the scaling of field-based biological, physical and chemical measurements to regional and continental scales, enabling a better understanding of the relationships between climate variability and change, land use change and invasive species, and their ecological consequences in areas not directly sampled by the NEON facilities. However, successful up-scaling of in situ measurements requires a flight sampling design that captures environmental heterogeneity and diversity (i.e., ecological and topographic gradients), is sensitive to temporal system variation (e.g., phenology), and can respond to major disturbance events. Alignment of airborne campaigns - composed of two payloads for nominal science acquisitions and one payload for PI-driven rapid-response campaigns -- with other ground, airborne (e.g., AVIRIS) and satellite (e.g., Landsat, MODIS) collections will further facilitate scaling between sensors and data sources of varying spatial and spectral resolution and extent. This presentation will discuss the approach, challenges and future goals associated with the development of NEON AOP's sampling design, using examples from the 2013 nominal flight campaigns in the Central Plains (NEON Domain 10) and the Pacific Southwest (Domain 17), and the rapid response flight campaign of the High Park Fire site outside of Fort Collins, CO. Determination of the specific flight coverage areas for each campaign involved analysis of the landscape scale ecological, geophysical and bioclimatic attributes and trends most closely associated with the primary science questions NEON data is addressing in each domain. An effort was made to capture the range of spatial and temporal variability at each site and across multiple sites so as to enable the science community to extrapolate across multiple scales, from organisms to landscapes to domain- and continental-scales using a variety of field and remotely sensed data.

  2. Axon-schwann cell interaction in the squid nerve fibre

    PubMed Central

    Villegas, Jorge

    1972-01-01

    The electrical properties of Schwann cells and the effects of neuronal impulses on their membrane potential have been studied in the giant nerve fibre of the squid. 1. The behaviour of the Schwann cell membrane to current injection into the cell was ohmic. No impulse-like responses were observed with displacements of 35 mV in the membrane potential. The resistance of the Schwann cell membrane was found to be approximately 103 ? cm2. 2. A long-lasting hyperpolarization is observed in the Schwann cells following the conduction of impulse trains by the axon. Whereas the propagation of a single impulse had little effect, prolonged stimulation of the fibre at 250 impulses/sec was followed by a hyperpolarization of the Schwann cell that gradually declined over a period of several minutes. 3. The prolonged effects of nerve impulse trains on the Schwann cell were similar to those produced by depolarizing current pulses applied to the axon by the voltage-clamp technique. Thus, a series of depolarizing pulses in the axon was followed by a long-lasting hyperpolarization of the Schwann cells. In contrast, the application of a series of hyperpolarizing 100 mV pulses at a frequency of 1/sec had no apparent effects. 4. Changes in the external potassium concentration did not reproduce the long-lasting effects of nerve excitation. 5. The hyperpolarizing effects of impulse trains were abolished by the incubation of the nerve fibre in a sea-water solution containing trypsin. 6. These findings are discussed in relation to the possible mechanisms that might be responsible for the long-lasting hyperpolarizations of the Schwann cells. PMID:5074387

  3. The DC-SQUID-based Magnetocardiographic Systems for Clinical Use

    NASA Astrophysics Data System (ADS)

    Maslennikov, Yu. V.; Primin, M. A.; Slobodchikov, V. Yu.; Khanin, V. V.; Nedayvoda, I. V.; Krymov, V. A.; Okunev, A. V.; Moiseenko, E. A.; Beljaev, A. V.; Rybkin, V. S.; Tolcheev, A. V.; Gapelyuk, A. V.

    The new line of dc-SQUID-based magnetocardiographic (MCG) systems (named as the "MAG-SCAN"-family) is designed, fabricated and tested. These systems are intended for routine MCG investigations of patients at conditions of real clinical electrophysiological labs. The "MAG-SCAN"-family includes the line of MCG devices compatible in terms of hardware and software with number of measuring channels from 1 to 36. Experimental prototypes of 7- and 9-channel MCG-systems (the models "MAG-SCAN-07" and "MAG-SCAN-09" fabricated at CRYOTON Co. Ltd.) were installed in a few hospitals of Moscow city and operated in an unshielded environment of usual clinical labs. Well balanced second-order gradiometers have been used for MCG data recording. They demonstrated an intrinsic noise level better than 5 fT/?Hz. The total noise level of about 20-40 fT/?Hz was measured at urban conditions of Moscow city. The package of special software (named as the "SOFTMAG") was developed as two autonomous subsystems that allow the preprocessing of the heart magnetic signals and the spatio-temporal analysis of the field characteristics and the field sources. The software employs the algorithms for the analysis and estimation of the spatio-temporal characteristics of the heart magnetic field and the correspondent electrical currents distributions. More than 2000 investigations of different volunteers including healthy persons, patients with high blood-pressure, ischemic disease (IHD), chronic obstructive pulmonary disease (COPD) and bronchial asthma (BA) were carried out and sets of MCG-parameters specific for each group were found.

  4. Intracellular calcium buffering capacity in isolated squid axons

    PubMed Central

    Brinley, FJ; Tiffert, T; Scarpa, A; Mullins, LJ

    1977-01-01

    Changes in ionized calcium were studied in axons isolated from living squid by measuring absorbance of the Ca binding dye Arsenazo III using multiwavelength differential absorption spectroscopy. Absorption changes measured in situ were calibrated in vitro with media of ionic composition similar to axoplasm containing CaEGTA buffers. Calcium loads of 50-2,500 ?mol/kg axoplasm were induced by microinjection, by stimulation in 112 mM Ca seawater, or by soaking in choline saline with 1-10 mM Ca. Over this range of calcium loading of intact axoplasm, the ionized calcium in the axoplasm rose about 0.6 nM/?M load. Similar loading in axons preteated with carbonyl cyanide 4- trifluoromethoxyphenylhydrazone (FCCP) to inhibit the mitochondrial proton gradient increased ionized calcium by 5-7 percent of the imposed load, i.e. 93-95 percent of the calcium load was buffered by a process insensitive to FCCP. This FCCP- insensitive buffer system was not saturated by the largest calcium loads imposed, indicating a capacity of at least several millimolar. Treatment of previously loaded axons with FCCP or apyrase plus cyanide produced rises in ionized calcium which could be correlated with the extent of the load. Analysis of results indicated that, whereas only 6 percent of the endogenous calcium in fresh axons is stored in the FCCP-sensitive (presumably mitochondrial) buffer system, about 30 percent of an imposed exogenous load in the range of 50-2,500 ?M is taken up by this system. PMID:894260

  5. Translocation of vesicles from squid axoplasm on flagellar microtubules.

    PubMed

    Gilbert, S P; Allen, R D; Sloboda, R D

    Directed intracellular particle movement is a fundamental process characteristic of all cells. During fast axonal transport, membranous organelles move at rapid rates, from 1 to 5 micron s-1, in either the orthograde or retrograde direction along the neurone and can traverse distances as long as 1 m (for reviews, see refs 1-3). Recent studies indicate that this extreme example of intracellular motility can occur along single microtubules, but the molecules generating the motile force have not been identified or localized. It is not known whether the force-transducing 'motor' is associated with the moving particle or with the microtubule lattice. To distinguish between these hypotheses and to characterize the membrane-cytoskeletal interactions that occur during vesicle translocations, we have developed a reconstituted model for microtubule-based motility. We isolated axoplasmic vesicles from the giant axon of the squid Loligo pealei as described previously. The vesicles (35-475 nm in diameter) were then added to axonemes of Arbacia punctulata spermatozoa that served as a source of microtubules. Axonemes were used because the tubulin subunit lattice of the A-subfibre of a given outer doublet is the same as the subunit lattice of neuronal microtubules along which motility occurs. Moreover, all the microtubules of a single axoneme show the same structural polarity, indicating that the axoneme represents an oriented microtubule substrate. Here we demonstrate that vesicle motility is ATP-dependent, that it is not mediated by the flagellar force-transducing molecule dynein and that the direction of movement is not specified by microtubule polarity. PMID:2582264

  6. 76 FR 3044 - Fisheries of the Exclusive Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-19

    ... harvest specifications for groundfish of the GOA (75 FR 11749, March 12, 2010). In accordance with Sec... Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the Gulf of Alaska AGENCY: National...: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for sculpins, sharks, squid,...

  7. Multi-elemental concentrations in the tissues of the oceanic squid Todarodes filippovae from Tasmania and the southern Indian Ocean.

    PubMed

    Kojadinovic, Jessica; Jackson, Christine H; Cherel, Yves; Jackson, George D; Bustamante, Paco

    2011-07-01

    This study investigates 14 elements (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn) in the tissues of the oceanic ommastrephid squid Todarodes filippovae from waters surrounding le Amsterdam (southern Indian Ocean) and Tasmania (Australia). As for other cephalopod species, the digestive gland and branchial hearts showed the highest concentrations of many elements (Ag, Cd, Se, V and Zn, and Cr and Ni, respectively) highlighting their role in bioaccumulation and detoxification processes. With the exception of As and Hg, the muscles showed relatively low trace element concentrations. Squid size was positively correlated to Ag, As, Cd, Hg and Zn concentrations in Tasmanian squid and negatively correlated to all but Hg and Zn concentrations in le Amsterdam squid. Furthermore, no differences in elemental concentrations were noted between sexes. There were, however, some differences between mated and non-mated females from Tasmania. Comparing elemental concentrations in squid from both islands, higher concentrations of Cd, Co, Cr, Ni, Pb and V in squid sampled in le Amsterdam reflect different exposure conditions. When considering T. filippovae as a dietary resource for humans it should be noted that, given their Hg content, squids from le Amsterdam are not recommended for consumption on a regular basis. Moreover, regardless of the squid's origin, digestive glands should be avoided as Cd and Hg concentrations were above the European Union authorized limits in these organs. PMID:21481467

  8. Study on nondestructive inspection using HTS-SQUID for friction stir welding between dissimilar metals

    NASA Astrophysics Data System (ADS)

    Hatsukade, Y.; Takahashi, T.; Yasui, T.; Tsubaki, M.; Fukumono, M.; Tanaka, S.

    2007-10-01

    We have developed an SQUID-NDI technique for evaluation of friction stir welding (FSW) between aluminum alloy A6063 and stainless steel SUS304 from the electric conductivities in board specimens bonded by FSW. A SQUID-NDI system employing an HTS-SQUID gradiometer was constructed to measure current distribution in the FSW specimens by applying voltage to the specimen. By measuring field gradients dBz/dy and dBz/dx above the FSW specimens made with various FSW conditions and then converting them to current vector Jx and Jy, conductivities of FSW areas were estimated. Due to the difference in the FSW conditions, the conductivity distributions varied dramatically. From these results, it was suggested that the conductivities in FSW areas should be varied due to the temperature heated by the friction between the milling tool and the materials.

  9. Cryogenic time-domain multiplexer based on SQUID arrays and superconducting/normal conducting switches

    NASA Astrophysics Data System (ADS)

    Beev, N.; Kiviranta, M.; van der Kuur, J.; Bruijn, M.; Brandel, O.; Linzen, S.; Fritzsch, L.; Ahoranta, J.; Penttilä, J.; Roschier, L.

    2014-05-01

    We have demonstrated the operation of a 12-channel Beyer-style SQUID-based time domain multiplexer. It was manufactured using a fabrication process that is cross-compatible between VTT and IPHT-Jena. The multiplexer consists of twelve 12-SQUID series arrays, each shunted by a Zappe-style interferometer array acting as a flux-controlled superconducting/normal conducting switch. By keeping all switches but one in the superconducting state, it is possible to select one active readout channel at a time. A flux feedback coil common to all SQUID arrays allows realization of a flux-locked loop. We present characteristics of the multiplexer and measurement data from experiments with a 25-pixel X-ray calorimeter array operated at T < 100 mK in a dilution refrigerator.

  10. Impact of air gun noise on the behaviour of marine fish and squid.

    PubMed

    Fewtrell, J L; McCauley, R D

    2012-05-01

    In this study various species of captive marine fish and one species of squid were exposed to the noise from a single air gun. Six trials were conducted off the coast of Western Australia with each trial using a different noise exposure regime. Noise levels received by the animals ranged between 120 and 184 dB re 1 ?Pa(2).s (SEL). Behavioural observations of the fish and squid were made before, during and after air gun noise exposure. Results indicate that as air gun noise levels increase, fish respond by moving to the bottom of the water column and swimming faster in more tightly cohesive groups. Significant increases in alarm responses were observed in fish and squid to air gun noise exceeding 147-151 dB re 1 ?Pa SEL. An increase in the occurrence of alarm responses was also observed as noise level increased. PMID:22385754

  11. Range-finding in squid using retinal deformation and image blur.

    PubMed

    Chung, Wen-Sung; Marshall, Justin

    2014-01-20

    Squid and other cephalopods catch prey with remarkable speed and precision [1]. Before the strike occurs, they encounter the difficult task of judging an object's distance and size in the contrast-poor world of the mid-water environment [1-4]. Here we describe a solution to this common problem underwater, where a large portion of a squid's dorso-temporal retina is intentionally blurred. This apparently counter-adaptive 'retinal bump' is combined with a vertical bobbing behavior that scans objects of interest from focused to defocused retinal regions. The image focus differential changes sharply at precisely the distance equivalent to tentacle length and enables the squid, Sepioteuthis lessoniana, to capture prey. This unique range-finding mechanism is an adaptation to hunting, defense, and object size identification in an environment where the depth cues found on land are less reliable. PMID:24456975

  12. Characterization of magnetite nanoparticles for SQUID-relaxometry and magnetic needle biopsy

    PubMed Central

    Adolphi, Natalie L.; Huber, Dale L.; Jaetao, Jason E.; Bryant, Howard C.; Lovato, Debbie M.; Fegan, Danielle L.; Venturini, Eugene L.; Monson, Todd C.; Tessier, Trace E.; Hathaway, Helen J.; Bergemann, Christian; Larson, Richard S.; Flynn, Edward R.

    2009-01-01

    Magnetite nanoparticles (Chemicell SiMAG-TCL) were characterized by SQUID-relaxometry, susceptometry, and TEM. The magnetization detected by SQUID-relaxometry was 0.33% of that detected by susceptometry, indicating that the sensitivity of SQUID-relaxometry could be significantly increased through improved control of nanoparticle size. The relaxometry data were analyzed by the moment superposition model (MSM) to determine the distribution of nanoparticle moments. Analysis of the binding of CD34-conjugated nanoparticles to U937 leukemia cells revealed 60,000 nanoparticles per cell, which were collected from whole blood using a prototype magnetic biopsy needle, with a capture efficiency of >65% from a 750 l sample volume in 1 minute. PMID:20161153

  13. Niobium and niobium nitride SQUIDs based on anodized nanobridges made with an atomic force microscope

    NASA Astrophysics Data System (ADS)

    Faucher, M.; Fournier, T.; Pannetier, B.; Thirion, C.; Wernsdorfer, W.; Villegier, J. C.; Bouchiat, V.

    2002-03-01

    We present a fabrication method of superconducting quantum interference devices (SQUIDs) based on direct write lithography with an atomic force microscope (AFM). This technique involves maskless local anodization of Nb or NbN ultrathin films using the voltage biased tip of the AFM. The SQUIDs are of weak-link type, for which two geometries have been tested: Dayem and variable thickness nanobridges. The magnetic field dependence of the maximum supercurrent Ic( ?) in resulting SQUIDs is thoroughly measured for different weak link geometries and for both tested materials. It is found that the modulation shape and depth of Ic( ?) curves are greatly dependent on the weak link size. We analyze the results taking into account the kinetic inductance of nanobridges and using the Likharev-Yakobson model. Finally we show that the present resolution reached by this technique (20 nm) enables us to fabricate Nb weak-links which behavior approaches those of ideal Josephson junctions.

  14. Failure Analysis of CCD Image Sensors Using SQUID and GMR Magnetic Current Imaging

    NASA Technical Reports Server (NTRS)

    Felt, Frederick S.

    2005-01-01

    During electrical testing of a Full Field CCD Image Senor, electrical shorts were detected on three of six devices. These failures occurred after the parts were soldered to the PCB. Failure analysis was performed to determine the cause and locations of these failures on the devices. After removing the fiber optic faceplate, optical inspection was performed on the CCDs to understand the design and package layout. Optical inspection revealed that the device had a light shield ringing the CCD array. This structure complicated the failure analysis. Alternate methods of analysis were considered, including liquid crystal, light and thermal emission, LT/A, TT/A SQUID, and MP. Of these, SQUID and MP techniques were pursued for further analysis. Also magnetoresistive current imaging technology is discussed and compared to SQUID.

  15. RF Amplifiers Based on DC SQUID for 3-4 GHz Band

    NASA Astrophysics Data System (ADS)

    Prokopenko, G. V.; Osborn, K. D.; Shitov, S. V.; Maezawa, M.; Sirois, A. J.; Cicak, K.; Simmonds, R. W.

    2006-03-01

    DC SQUID based RF Amplifiers (SRFAs) are known to dissipate very little power and can be integrated on-chip with existing micro-fabricated circuits for low-noise, low temperature measurements. The SRFA chip has 4 independent channels, which amplify at different signal frequencies and have integrated output filters, which prevent the leakage of high frequency resonances associated with the Josephson frequency. A compact two-layer input signal coil is integrated with the washer of the SQUID (L=20 pH) and planar capacitors for tuned frequency and impedance matching. The input reflected power is further reduced using proven balanced configuration on the SQUID. The shunt resistors are made from a multilayer film Ti(2 nm)/Pd(55 nm)/Ti(2 nm), which allow the SRFA to operate down to 0.4 K. Low-noise SRFAs have been tested with an operating frequency range of 3-4 GHz.

  16. Development of multielement SQUID arrays for magnetic source imaging. Final report

    SciTech Connect

    Hassenzahl, W.V.; Casper, T.A.; Miller, D.E.

    1995-06-01

    Superconducting quantum interference devices (SQUIDs) were initially developed in the late 1960s as biomagnetic detectors to monitor electrical activity in the body. Research in this area has increased in recent years as electronics and computer diagnositcs have improved. The basis of this proposal was to asses: (1) the advantages of using this technique over other technologies and (2) the requirements for development of a complete system that would advance the state of the art. In our assessment of this technology, we collaborated with the Medical School at the University of California, San Francisco (UCSF), General Electric (GE), Biomagnetic Technologies (BTi), and Conductus, each of which has unqiue expertise in biomedical applications. UCSF is one of the foremost clinical institutions in the US developing imaging techniques. GE is the primary US supplier of medical imaging systems. Conductus is the major US supplier of SQUIDs and BTi is a developer of SQUID array systems.

  17. Molecular Studies of Fly-Borne Pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vector-borne diseases are among the most significant threats to agriculture and human health. Mosquitoes are the most significant vectors of disease, but other biting and blood feeding flies such as black flies (Simuliidae), keds (Hippoboscidae), bot flies (Oestridae), and stable flies (Muscidae) a...

  18. Dewatered sewage biosolids provide a productive larval habitat for stable flies and house flies (Diptera: Muscidae).

    PubMed

    Doud, C W; Taylor, D B; Zurek, L

    2012-03-01

    Species diversity and seasonal abundance of muscoid flies (Diptera: Muscidae) developing in biosolid cake (dewatered biosolids) stored at a wastewater treatment facility in northeastern Kansas were evaluated. Emergence traps were deployed 19 May through 20 October 2009 (22 wk) and 27 May through 18 November 2010 (25 wk). In total, 11,349 muscoid flies were collected emerging from the biosolid cake. Stable flies (Stomoxys calcitrans (L.)) and house flies (Musca domestica (L.)), represented 80 and 18% of the muscoid flies, respectively. An estimated 550 stable flies and 220 house flies per square-meter of surface area developed in the biosolid cake annually producing 450,000 stable flies and 175,000 house flies. Stable fly emergence was seasonally bimodal with a primary peak in mid-July and a secondary peak in late August. House fly emergence peaked with the first stable fly emergence peak and then declined gradually for the remainder of the year. House flies tended to emerge from the biosolid cake sooner after its deposition than did stable flies. In addition, house fly emergence was concentrated around midsummer whereas stable fly emergence began earlier in the spring and continued later into the fall. Biosolid age and temperature were the most important parameters affecting emergence for house flies and stable flies, whereas precipitation was not important for either species. This study highlights the importance of biosolid cake as a larval developmental habitat for stable flies and house flies. PMID:22493845

  19. Subtropical Fruit Fly Invasions into Temperate Fruit Fly Territory in California's San Joaquin Valley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Subtropical fruit fly species including peach fruit fly, Bactrocera zonata (Saunders); melon fly, B. cucurbitae (Coquillett); oriental fruit fly, B. dorsalis (Hendel); and Mediterranean fruit fly, Ceratitis capitata Weidemann, have been detected in the past decade in the San Joaquin Valley of Califo...

  20. Comprehensive Model of Jumbo Squid Dosidicus gigas Trophic Ecology in the Northern Humboldt Current System

    PubMed Central

    Alegre, Ana; Ménard, Frédéric; Tafur, Ricardo; Espinoza, Pepe; Argüelles, Juan; Maehara, Víctor; Flores, Oswaldo; Simier, Monique; Bertrand, Arnaud

    2014-01-01

    The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?). Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters. PMID:24465788

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

    NASA Technical Reports Server (NTRS)

    Lu, D. F.; Fan, Chang-Xin; Ruan, J. Z.; Han, S. G.; Wong, K. W.; Sun, G. F.

    1995-01-01

    A SQUID is the most sensitive device to detect change in magnetic field. A nondestructive testing (NDT) device using high temperature SQUID's and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUID's. 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.

  2. Managing the Fruit Fly Experiment.

    ERIC Educational Resources Information Center

    Jeszenszky, Arleen W.

    1997-01-01

    Describes a sophisticated version of the fruit fly experiment for teaching concepts about genetics to biology students. Provides students with the opportunity to work with live animals over an extended period. (JRH)

  3. Aerobic respiratory costs of swimming in the negatively buoyant brief squid Lolliguncula brevis.

    PubMed

    Bartol, I K; Mann, R; Patterson, M R

    2001-11-01

    Because of the inherent inefficiency of jet propulsion, squid are considered to be at a competitive disadvantage compared with fishes, which generally depend on forms of undulatory/oscillatory locomotion. Some squid, such as the brief squid Lolliguncula brevis, swim at low speeds in shallow-water complex environments, relying heavily on fin activity. Consequently, their swimming costs may be lower than those of the faster, more pelagic squid studied previously and competitive with those of ecologically relevant fishes. To examine aerobic respiratory swimming costs, O(2) consumption rates were measured for L. brevis of various sizes (2-9 cm dorsal mantle length, DML) swimming over a range of speeds (3-30 cm s(-1)) in swim tunnel respirometers, while their behavior was videotaped. Using kinematic data from swimming squid and force data from models, power curves were also generated. Many squid demonstrated partial (J-shaped) or full (U-shaped) parabolic patterns of O(2) consumption rate as a function of swimming speed, with O(2) consumption minima at 0.5-1.5 DML s(-1). Power curves derived from hydrodynamic data plotted as a function of swimming speed were also parabolic, with power minima at 1.2-1.7 DML s(-1). The parabolic relationship between O(2) consumption rate/power and speed, which is also found in aerial flyers such as birds, bats and insects but rarely in aquatic swimmers because of the difficulties associated with low-speed respirometry, is the result of the high cost of generating lift and maintaining stability at low speeds and overcoming drag at high speeds. L. brevis has a lower rate of O(2) consumption than the squid Illex illecebrosus and Loligo opalescens studied in swim tunnel respirometers and is energetically competitive (especially at O(2) consumption minima) with fishes, such as striped bass, mullet and flounder. Therefore, the results of this study indicate that, like aerial flyers, some negatively buoyant nekton have parabolic patterns of O(2) consumption rate/power as a function of speed and that certain shallow-water squid using considerable fin activity have swimming costs that are competitive with those of ecologically relevant fishes. PMID:11719530

  4. Comparison of Ising Spin Glass Noise to Flux and Inductance Noise in SQUIDs

    NASA Astrophysics Data System (ADS)

    Chen, Zhi; Yu, Clare C.

    2010-06-01

    Recent experiments implicate spins on the surface of metals as the source of flux and inductance noise in SQUIDs. We present Monte Carlo simulations of 2D and 3D Ising spin glasses that produce magnetization noise SM consistent with flux noise. At low frequencies SM is a maximum at the critical temperature TC in three dimensions, implying that flux noise should be a maximum at TC. The second spectra of the magnetization noise and the noise in the susceptibility are consistent with experimentally measured SQUID inductance noise.

  5. A single-channel SQUID magnetometer for measuring magnetic field of human fetal heart

    NASA Astrophysics Data System (ADS)

    Bachir, Wesam; Grot, Przemyslaw; Dunajski, Zbigniew

    2004-07-01

    A non-invasive single-channel SQUID magnetometer for fetal magnetocardiography has been developed. The signal is picked-up with a wire wound third order gradiometer. The optimal configuration of the flux transformer is a trade-off between sufficient sensitivity for the magnetic field originated in fetal heart and effective immunity against the ambient magnetic noise. The over all system performance together with the measuring probe and SQUID electronics is described. The balancing of the third order flux transformer is discussed as well as the signal processing of fetal magnetocardiogram recordings.

  6. Role of squid in the Southern Ocean pelagic ecosystem and the possible consequences of climate change

    NASA Astrophysics Data System (ADS)

    Rodhouse, Paul G. K.

    2013-10-01

    Southern Ocean squid are important predators and prey and are a potential fishery resource. Their future under climate change is analysed from predictions of change by 2100 and assessments of the effects on squid biology. There are ˜18 Antarctic species of squid. Young feed primarily on crustaceans and switch later to fishes. They are preyed on by odontocetes, seals and seabirds - which together consume ˜34×106tyr-1 - and fish. As predators, squid are second to fish as biomass producers but recent evidence suggests predator consumption of squid needs to be reassessed. Fatty acid composition and stable nitrogen isotope ratios indicate some predators consume less squid in their diet than gut contents data suggest. Southern Ocean oceanography is unique in having circumpolar circulation and frontal systems and at high latitudes it is heavily influenced by sea ice. The Antarctic Peninsula is among the fastest warming regions worldwide but elsewhere the Southern Ocean is warming more slowly and the Ross Sea is probably cooling. Sea ice is receding in the Peninsula region and increasing elsewhere. Modelled predictions for 2100 suggest although the Southern Ocean will warm less than other oceans and sea ice will reduce. The Antarctic Circumpolar Current may shift slightly southwards with intensification of westerly winds but resolution of the models is insufficient to predict mesoscale change. Globally, pH of seawater has decreased by 0.1 units since the mid-1900s and is predicted to decrease by another 0.5 units by 2100. Impact on calcifying organisms will be high in the cold Southern Ocean where solubility of calcium carbonate is high. Predicted temperature increases are unlikely to have major effects on squid other than changes in distribution near the limits of their range; acidification may have greater impact. Small changes in large scale circulation are unlikely to affect squid but changes in mesoscale oceanography may have high impact. Change in sea ice extent may not have a direct effect but consequent ecosystem changes could have a major impact. Cephalopods are ecological opportunists adapted to exploit favourable environmental conditions. Given their potential to evolve fast, change in the Southern Ocean pelagic ecosystem might act in their favour.

  7. Oral administration of pharmacologically active substances to squid: a methodological description.

    PubMed

    Berk, William; Teperman, Jake; Walton, Kerry D; Hirata, Kazunari; Sugimori, Mutsuyuki; Llinas, Rodolfo R

    2009-02-01

    The squid giant synapse is a well-defined experimental preparation for the study of ligand-dependant synaptic transmission. Its large size gives direct experimental access to both presynaptic and postsynaptic junctional elements, allowing direct optical, biophysical, and electrophysiological analysis of depolarization-release coupling. However, this important model has not been utilized in pharmacological studies, other than those implementable acutely in the in vitro condition. A method is presented for oral administration of bioactive substances to living squid. Electrophysiological characterization and direct determination of drug absorption into the nervous system demonstrate the administration method described here to be appropriate for pharmacological research. PMID:19218487

  8. SQUID-Based Microwave Cavity Search for Dark-Matter Axions

    SciTech Connect

    Asztalos, S. J.; Carosi, G.; Hagmann, C.; Kinion, D.; Bibber, K. van; Hotz, M.; Rosenberg, L. J; Rybka, G.; Hoskins, J.; Hwang, J.; Sikivie, P.; Tanner, D. B.; Bradley, R.; Clarke, J.

    2010-01-29

    Axions in the mueV mass range are a plausible cold dark-matter candidate and may be detected by their conversion into microwave photons in a resonant cavity immersed in a static magnetic field. We report the first result from such an axion search using a superconducting first-stage amplifier (SQUID) replacing a conventional GaAs field-effect transistor amplifier. This experiment excludes KSVZ dark-matter axions with masses between 3.3 mueV and 3.53 mueV and sets the stage for a definitive axion search utilizing near quantum-limited SQUID amplifiers.

  9. On-chip SQUID measurements in the presence of high magnetic fields.

    PubMed

    Chen, Lei; Wernsdorfer, Wolfgang; Lampropoulos, Christos; Christou, George; Chiorescu, Irinel

    2010-10-01

    We report a low temperature measurement technique and the magnetization data of a quantum molecular spin, by implementing an on-chip SQUID technique. This technique enables SQUID magnetometry in high magnetic fields, up to 7 T. The main challenges and the calibration process are detailed. The measurement protocol is used to observe quantum tunneling jumps of the S = 10 molecular magnet, Mn(12)-tBuAc. The effect of a transverse field on the tunneling splitting for this molecular system is addressed as well. PMID:20829574

  10. SQUID-based microwave cavity search for dark-matter axions.

    PubMed

    Asztalos, S J; Carosi, G; Hagmann, C; Kinion, D; van Bibber, K; Hotz, M; Rosenberg, L J; Rybka, G; Hoskins, J; Hwang, J; Sikivie, P; Tanner, D B; Bradley, R; Clarke, J

    2010-01-29

    Axions in the microeV mass range are a plausible cold dark-matter candidate and may be detected by their conversion into microwave photons in a resonant cavity immersed in a static magnetic field. We report the first result from such an axion search using a superconducting first-stage amplifier (SQUID) replacing a conventional GaAs field-effect transistor amplifier. This experiment excludes KSVZ dark-matter axions with masses between 3.3 microeV and 3.53 microeV and sets the stage for a definitive axion search utilizing near quantum-limited SQUID amplifiers. PMID:20366699

  11. Magnesium content and net fluxes in squid giant axons

    PubMed Central

    1979-01-01

    The Mg content of axons freshly dissected from living specimens of the tropical squid Doryteuthis plei was determined by atomic absorption spectroscopy to be 4.2 +/- 0.2 mmol/kg axoplasm. The axon's ability to maintain this physiological content of total intracellular Mg([Mg]i) was studied. Mgi was shown to be a linear function of Mgo when Mgo of incubating fluid was varied between 0 and 250 mM. When Mgo = 15 mM, Mgi was found to be the same in incubated fibers as in fibers freshly dissected. Mgi levels were unaffected by depolarization of the membrane by high Ko. Stimulation resulted in an extra influx of Mg of 0.05 pmol/(cm2 . impulse) when Mgo = 55 mM. Mgi was found to be a complicated function of the concentration of extracellular Na or Li (Xo), which was substituted for Tris. With 385 mM Lio the Mgi level was found to be 2.5-fold larger than the level observed with 385 mM Nao after incubation for 3 h. The function relating Mgo to Xo was qualitatively unaffected in axons poisoned with the mitochondrial uncoupler carbonyl cyanide, p-trifluorome-thoxy-phenylhydrazone (FCCP) and the inhibitor of glycolysis, iodoacetic acid (IAA); the absolute levels of Mgi, however, were some 30% higher in the poisoned axons at all [X]o explored. 2 h incubation of axons in a 333 mM Mg, 40 mM Li solution increased Mgi 3.5-fold in control axons and 5-fold in poisoned axons. These Mg-loaded axons were able to recover physiological levels of Mgi with a half-time of 3-5 h only if kept in a solution which contained Na (220 mM) regardless of whether the axons had been inhibited with FCCP + IAA. Therefore, it may be concluded that the physiological Mgi concentration can be maintained by the Na electrochemical gradient, even when the axon is metabolically poisoned. PMID:536737

  12. Excitation of the squid giant axon by general anaesthetics.

    PubMed Central

    Haydon, D A; Simon, A J

    1988-01-01

    1. The effects of 'clinical' concentrations of some general anaesthetics on the minimum stimulus required to produce an action potential in the squid giant axon have been examined as a function of time from exposure to the anaesthetic. The resting potential in these experiments was also monitored. 2. The minimum stimulus varied with time in different ways for different anaesthetics. For chloroform, diethyl ether, n-pentanol, halothane and cyclopropane the stimulus initially declined, reached a minimum after about 3 min and then recovered to near-normal values at 10-15 min. For n-pentane, cyclopentane and, to a lesser extent methoxyflurane, the stimulus often declined to such low values that the axon exhibited spontaneous action potentials which persisted until the anaesthetic was removed. For one substance, the experimental local anaesthetic diheptanoyl phosphatidylcholine, the stimulus increased considerably over the 10-15 min required to reach the steady state. In all instances the axons reverted to normal behaviour after removal of the anaesthetic although the time course by which they did so was more variable than for the initial exposure. 3. For all anaesthetics the resting potential changed in the positive direction monotonically by ca. 1-5 mV and reached a steady state in approximately 3 min. On removal of the anaesthetic the resting potential returned to normal, also monotonically. 4. The voltage-gated Na+ and K+ currents were significantly affected even at the low anaesthetic concentrations used. Estimates of the changes in the Hodgkin-Huxley parameters were obtained partly by direct experiment and partly from results previously obtained for higher anaesthetic concentrations. 5. The time dependencies of the minimum stimuli have been accounted for semi-quantitatively in terms of the resting potential changes and the voltage shifts in the Na+ current steady-state activation, and the time dependencies respectively of these two parameters. 6. Quantitative calculations of the resting potential changes for comparison with experiment have been made based on the changes in K+ conductance determined in the preceding paper (Haydon, Requena & Simon, 1988) and changes in the Hodgkin-Huxley parameters of the Na+ and delayed-rectifier K+ currents. 7. Calculations of the minimum stimulus in the steady state have been made from the experimental resting potential changes and from the anaesthetic-affected Hodgkin-Huxley parameters. Good agreement with the experimental stimuli was found, especially in the prediction of high and low values. PMID:3236244

  13. CyroSQUID: a SQUID-based magnetic-field sensor. Technical report No. 3 (Final), 15 August 1984-30 November 1987

    SciTech Connect

    Williamson, S.J.; Kaufman, L.

    1988-03-15

    A new type of neuromagnetometer was developed to enhance the capability for measuring the magnetic field of the human brain. This system - known as CryoSQUID - results from the marriage of two advanced technologies: a refrigerator incorporating closed-cycle operation of a pair of cryocoolers and a sensor incorporating the superconducting quantum interference device (SQUID). The apparatus is relatively small and requires no supply of liquid helium for initial cooling or operation. Only a source of electrical power is needed. Each sensor relies on a detection coil wound in the geometry of a second-order gradiometer so as to minimize the effects of ambient magnetic noise found in typical unshielded environments. The intrinsic noise level of CryoSQUID is comparable to a magnetic field sensitivity of 20 femtotesla within a one-hertz bandwidth. Residual noise at 1.2 Hz and its harmonics, contributed by the displacer in the Gifford-McMahon cooler, is virtually eliminated in real time by an adaptive filter run on a personal computer.

  14. Canopy Biomass Lidar (CBL) Acquisitions at NEON and TERN Forest Sites

    NASA Astrophysics Data System (ADS)

    Schaaf, C.; Paynter, I.; Saenz, E.; Peri, F.; Wang, Z.; Erb, A.; Yang, X.; Strahler, A. H.; Li, Z.; van Aardt, J. A.; Kelbe, D.; Romanczyk, P.; Cawse-Nicholson, K.; Krause, K.; Leisso, N.; Kampe, T. U.; Meier, C. L.; Ritz, C.; Chakrabarti, S.; Cook, T.; Howe, G.; Martel, J.; Hewawasam, K.; Douglas, E. S.; Newnham, G.; Schaefer, M.; Armston, J.; Muir, J.; Tindall, D.; Phinn, S. R.

    2013-12-01

    Terrestrial Laser Scanning (TLS) offers the ability to capture complex forest structure through 3D reconstruction of multiple laser return point clouds. These reconstructions provide detailed information on understory, mid-story and canopy structure and allow quantification of important ecosystem factors such as biomass, vegetation productivity, forest health and response to disturbance. Used in conjunction with airborne lidar and satellite imaging, TLS is a powerful calibration/validation tool for improved regional scale ecological surveying and modeling. Repeated deployments facilitate the estimation of growth rates, nutrient fluxes, and other essential parameters in global scale climate and biogeochemic modeling. Routine TLS acquisitions at long-term research sites provide an opportunity to capture temporal variations due to natural and anthropogenic effects. While discrete return and full waveform TLS instruments (such as the Dual Wavelength Echidna Lidar (DWEL)) are increasingly being deployed, there is also a need for high speed, low-cost, highly portable TLS instruments to augment these more powerful, high resolution lidars. The Canopy Biomass Lidar (CBL) is a light, fast-scanning, time-of-flight, 905nm, TLS instrument, conceived by the Katholieke Universiteit Leuven (KUL) and refined by the Rochester Institute of Technology (RIT). Two CBLs, constructed by the University of Massachusetts Boston, were deployed alongside the full waveform DWEL (developed by Boston University, University of Massachusetts Lowell, University of Massachusetts Boston, and the Commonwealth Scientific and Industrial Research Organisation (CSIRO)) during the June 2013 NEON Airborne Observation Platform (AOP) campaign in the Sierra National Forest, CA. Three sites were characterized by both the CBLs and the DWEL in the Soaproot and Teakettle regions (where relocatable NEON towers will be situated). Up to 5 multiple scans were acquired by the DWEL, with an additional 8-12 scans obtained with the CBLs, to generate coincident 3D point clouds. Additional NEON sites in the Soaproot region were also scanned by the RIT CBL, while field teams collected forestry measures and LAI estimates. NEON full waveform airborne LiDAR and hyperspectral imagery were captured concurrently. In July 2013, the UMB CBL scanners were again deployed alongside the DWEL at three long term forest monitoring locations in Queensland, Australia as part of a TLS field activity, sponsored by the Terrestrial Laser Scanning International Interest Group (TLSiig), the Terrestrial Ecosystem Research Network (TERN) and CSIRO, Australia. The sites were located at Karawatha Forest Park, a TERN Supersite location and in the Brisbane Forest Park portion of D'Aguilar National Park. Again multiple scans were acquired over each 50x50m site (13 lower range CBL scans interposed at and between the DWEL scans) to generate multiple point clouds and detailed 3D reconstructions. These and further efforts this fall in the vicinity of the NEON tower site at Harvard Forest, MA, recognize the substantial value TLS offers to ongoing data collection at globally-recognized long-term field sites such as NEON and TERN. Highly-portable TLS such as the CBL allow efficient, frequent, expansive, and rapid response sampling to augment the more detailed information possible from instruments like the DWEL.

  15. Angular Correlation of Electrons Emitted by Double Auger Decay of K-Shell Ionized Neon

    NASA Astrophysics Data System (ADS)

    Jones, Matthew Philip

    2011-12-01

    We have investigated in detail the 4-body continuum state produced when core-ionized neon undergoes Double-Auger (DA) decay, using COLd Target Recoil Ion Momentum Spectroscopy (COLTRIMS ). We conducted the experiment at the Lawrence Berkeley National Laboratory's Advanced Light Source (LBNL-ALS) beamline 11.0.2. The synchrotron operated in 2-bunch mode and outputted an elliptically polarized, pulsed photon beam (hn=872.9eV), sufficient to K-shell ionize neon just above threshold. Our analysis supports research showing that Auger electrons tend to share energy asymmetrically. We qualitatively compared this result to Photo-Double Ionization (PDI) of helium. Further, we confirm research that shows how Auger electrons that share energy symmetrically can be modeled by the elastic-like knock-out process plus Post-Collision Interaction ( PCI) effects. New observations include the angular correlation between the photo-electron and each respective Auger electron, for specific ranges of energy sharing. We identify a broad feature in the asymmetric case that shows a level of interaction between electrons that until recently, has disagreed with theory. Additionally, we consider the angular correlation between the photo-electron and the momentum sum of the Auger electrons. We observe that the angular correlation between this sum and the photo-electron in the highly asymmetric case is nearly identical to the correlation between just the fast-Auger and the photo-electron - as expected. In the case of symmetric energy sharing, the sum momentum vector appears to be isotropic, particularly for small angles of interaction. Finally, we acknowledge two novel methods of calibration. The first, uses well known line-energies to calibrate the spectrometer. These lines correspond to the decay channels of core-excited neon, Ne(1 s-13p). The second, describes a method to statistically weight list-mode data in order to calibrate it to well known physical features (e.g., isotropic distributions).

  16. Quantum path-integral study of the phase diagram and isotope effects of neon.

    PubMed

    Ramrez, R; Herrero, C P

    2008-11-28

    The phase diagram of natural neon has been calculated for temperatures in the range of 17-50 K and pressures between 10(-2) and 2 x 10(3) bar. The phase coexistence between solid, liquid, and gas phases has been determined by the calculation of the separate free energy of each phase as a function of temperature. Thus, for a given pressure, the coexistence temperature was obtained by the condition of equal free energy of coexisting phases. The free energy was calculated by using nonequilibrium techniques such as adiabatic switching and reversible scaling. The phase diagram obtained by classical Monte Carlo simulations has been compared to that obtained by quantum path-integral simulations. Quantum effects related to the finite mass of neon cause that coexistence lines are shifted toward lower temperatures when compared to the classical limit. The shift found in the triple point amounts to 1.5 K, i.e., about 6% of the triple-point temperature. The triple-point isotope effect has been determined for (20)Ne, (21)Ne, (22)Ne, and natural neon. The simulation data show satisfactory agreement to previous experimental results, which report a shift of about 0.15 K between triple-point temperatures of (20)Ne and (22)Ne. The vapor pressure isotope effect has been calculated for both solid and liquid phases at triple-point conditions. The quantum simulations predict that this isotope effect is larger in the solid than in the liquid phase, and the calculated values show nearly quantitative agreement to available experimental data. PMID:19045868

  17. Optical Excitation and Decay Dynamics of Ytterbium Atoms Embedded in a Solid Neon Matrix

    SciTech Connect

    Xu, C.-Y.; Lu, Z.-T.; Hu, S.-M.; Singh, J.; Bailey, K.; Mueller, P.; O'Connor, T. P.; Welp, U.

    2011-08-26

    Neutral ytterbium atoms embedded in solid neon qualitatively retain the structure of free atoms. Despite the atom-solid interaction, the 6s6p {sup 3}P{sub 0} level is found to remain metastable with its lifetimes determined to be in the range of ten to hundreds of seconds. The atomic population can be almost completely transferred between the ground level and the metastable level via optical excitation and spontaneous decay. The dynamics of this process is examined and is used to explicitly demonstrate that the transition broadening mechanism is homogeneous.

  18. Electron impact ionization of neon and neonic ions under distorted-wave Born approximation

    NASA Astrophysics Data System (ADS)

    Zhou, Li-Xia; Yan, You-Guo

    2014-05-01

    The (e, 2e) triple differential cross sections of 2s orbitals of neon and neonic ions (Z = 11-14) are calculated using a distorted-wave Born approximation under coplanar asymmetric geometry. The calculated results show that, with the increase in the nuclear charge number Z, the amplitude of triple differential cross sections decreases. The angle difference between the binary peak position and the direction of momentum transfer gradually increases with the increase in the nuclear charge Z, and a new structure appears at an ejected angle 90 < ?2 < 120. Three kinds of collision processes are proposed to illustrate the formation mechanism of such collision peaks.

  19. Unusual under-threshold ionization of neon clusters studied by ion spectroscopy

    NASA Astrophysics Data System (ADS)

    Nagaya, K.; Sugishima, A.; Iwayama, H.; Murakami, H.; Yao, M.; Fukuzawa, H.; Liu, X.-J.; Motomura, K.; Ueda, K.; Saito, N.; Foucar, L.; Rudenko, A.; Kurka, M.; Kühnel, K.-U.; Ullrich, J.; Czasch, A.; Dörner, R.; Feifel, R.; Nagasono, M.; Higashiya, A.; Yabashi, M.; Ishikawa, T.; Togashi, T.; Kimura, H.; Ohashi, H.

    2013-08-01

    We carried out time-of-flight mass spectrometry for neon clusters that were exposed to intense free electron laser pulses with the wavelength of 62 nm, which induce optical transition from the ground state (2s2 2p6) to an excited state (2s2 2p5 nl ) in the Ne atoms. In contrast to Ne+ ions produced by two-photon absorption from isolated Ne atoms, the Ne+ ion yield from Ne clusters shows a linear dependence on the laser intensity (I). We discuss the ionization mechanisms which give the linear behaviour with respect to I and expected features in the electron emission spectrum.

  20. Experimental study of the effects of helium-neon laser radiation on repair of injured tendon

    NASA Astrophysics Data System (ADS)

    Xu, Yong-Qing; Li, Zhu-Yi; Weng, Long-Jiang; An, Mei; Li, Kai-Yun; Chen, Shao-Rong; Wang, Jian-Xin; Lu, Yu

    1993-03-01

    Despite extensive research into the biology of tendon healing, predictably restoring normal function to a digit after a flexor tendon laceration remains one of the most difficult problems facing the hand surgeon. The challenge of simultaneously achieving tendon healing while minimizing the peritendinous scar formation, which limits tendon gliding, has captured the attention of investigators for many years. It has been said that low-power density helium-neon laser radiation had effects on anti-inflammation, detumescence, progressive wound healing, and reducing intestinal adhesions. This experimental study aims at whether helium-neon laser can reduce injured tendon adhesions and improve functional recovery of the injured tendon. Fifty white Leghorn hens were used. Ten were randomly assigned as a normal control group, the other forty were used in the operation. After anesthetizing them with Amytal, a half of the profundus tendons of the second and third foretoes on both sides of the feet were cut. Postoperatively, the hens moved freely in the cages. One side of the toes operated on were randomly chosen as a treatment group, the other side served as an untreated control group. The injured tendon toes in the treatment group were irradiated for twenty minutes daily with a fiber light needle of helium-neon laser therapeutic apparatus (wavelength, 6328 angstroms) at a constant power density of 12.74 mW/cm2, the first exposure taking place 24 hours after the operation. The longest course of treatment was 3 weeks. The control group was not irradiated. At 3 days, 1, 2, 3, and 5 weeks after surgery, 8 hens were sacrificed and their tendons were examined. The experimental results: (1) active, passive flexion and tendon gliding functional recovery were significantly better in the treatment group (p < 0.01); (2) width and thickness of the tendon at the cut site were significantly smaller in the treatment group (p < 0.01); (3) degrees of tendon adhesions were significantly lighter in the treatment group (p < 0.05). The experimental results demonstrate helium-neon laser radiation had significant effects on anti-inflammation, detumescence, progressive hematoma absorbing, inhibiting the tendon extrinsic healing, reducing tendon adhesions, improving the tendon intrinsic healing, i.e., stimulating epitenon and endotenon cells proliferation and migrating into the gap, stimulating collagen synthesis in the tendon gap, and enhancing the late remodeling of fibrous peritendonous adhesion.