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Sample records for leucocephalus columnar cactus

  1. Pollination system of the Pilosocereus leucocephalus columnar cactus (tribe Cereeae) in eastern Mexico.

    PubMed

    Munguía-Rosas, M A; Sosa, V J; Jácome-Flores, M E

    2010-07-01

    It has been suggested that there is a geographic dichotomy in the pollination systems of chiropterophilous columnar cacti: in intra-tropical areas they are pollinated almost exclusively by bats, whereas in extratropical areas they are pollinated by bats, birds and bees. However, currently the studies are clumped both taxonomically (mainly Pachycereeae species) and geographically (mainly in the Tehuacan Valley and the Sonoran Desert). This clumping limits the possibility of generalising the pattern to other regions or cactus tribes. Only four of the 36 chiropterophilous cacti in Pilosocereus have been studied. Despite the tropical distribution of two Pilosocereus species, bees account for 40-100% of their fruit set. We examined how specialised is the pollination system of P. leucocephalus in eastern Mexico. As we studied tropical populations, we expected a bat-specialised pollination system. However, previous studies of Pilosocereus suggest that a generalised pollination system is also possible. We found that this cactus is mainly bat-pollinated (bats account for 33-65% of fruit set); although to a lesser degree, diurnal visitors also caused some fruit set (7-15%). Diurnal visitors were more effective in populations containing honeybee hives. P. leucocephalus is partially self-compatible (14-18% of fructification) but unable to set fruit without visitors. Despite the variation in pollination system, P. leucocephalus shows more affinity with other columnar cacti from tropical regions than with those from extratropical regions. Although we report here that a new species of tropical Pilosocereus is relatively bat-specialised, this Cereeae genus is more flexible in its pollination system than the Pachycereeae genera.

  2. Nurse Plants vs. Nurse Objects: Effects of Woody Plants and Rocky Cavities on the Recruitment of the Pilosocereus leucocephalus Columnar Cactus

    PubMed Central

    Munguía-Rosas, Miguel Angel; Sosa, Vinicio J.

    2008-01-01

    Background and Aims Most studies on cactus recruitment have focused on the role of woody plants as seedling facilitators. Although the spatial association of cacti with objects had been described, the mechanisms underlying this association remain unknown. The aims of this study were to identify which mechanisms facilitate the establishment of a columnar cactus under the shade and protection of objects and to compare these mechanisms with those involved in plant–plant facilitation. Methods Three split-split-plot field experiments were conducted to compare the effects of two microhabitats (inside rocky cavities and beneath plant canopies) on seed removal, germination, seedling survivorship and dry weight. Flat, open spaces were used as the control. For each microhabitat, the effect of seed or seedling protection and substrate limitation were explored; aboveground microclimate and some soil properties were also characterized. Key Results The permanence of superficial seeds was greater inside rocky cavities than beneath woody plant canopies or on flat, open areas. Germination was similar in cavities and beneath plant canopies, but significantly higher than on flat, open areas. Seedling survivorship was greater beneath plant canopies than inside cavities or on flat, open spaces. Conclusions The mechanisms of plant facilitation are different from those of object facilitation. There are seed–seedling conflicts involved in the recruitment of P. leucocephalus: nurse plants favour mainly seedling survivorship by providing a suitable microenvironment, while nurse objects mainly favour seed permanence, by protecting them from predators. PMID:18056054

  3. Sun/shade conditions affect recruitment and local adaptation of a columnar cactus in dry forests

    PubMed Central

    Miranda-Jácome, Antonio; Montaña, Carlos; Fornoni, Juan

    2013-01-01

    Background and Aims Facilitation among plants in water-limited environments (i.e. where evapotranspiration overcomes the availability of water during the growing season) has been considered a local adaptation to water and light conditions. Among cacti, early life-history stages can benefit from the facilitative effects of nurse plants that reduce solar radiation and water stress. However, whether light condition itself acts as an agent of selection through facilitation remains untested. The aim of this study was to determine (1) whether light conditions affect seedling recruitment, (2) whether the positive effect of shade on seedling recruitment is more intense under more stressful conditions and (3) whether shade condition (facilitation) reduces the magnitude of local adaptation on seedling recruitment relative to full sunlight conditions. Methods A reciprocal transplant experiment, coupled with the artificial manipulation of sun/shade conditions, was performed to test for the effects of local adaptation on germination, seedling survival and growth, using two demes of the columnar cactus Pilosocereus leucocephalus, representing different intensities of stressful conditions. Key Results Full sunlight conditions reduced recruitment success and supported the expectation of lower recruitment in more stressful environments. Significant local adaptation was mainly detected under full sunlight conditions, indicating that this environmental factor acts as an agent of selection at both sites. Conclusions The results supported the expectation that the magnitude of local adaptation, driven by the effects of facilitative nurse plants, is less intense under reduced stressful conditions. This study is the first to demonstrate that sun/shade conditions act as a selective agent accounting for local adaptation in water-limited environments, and that facilitation provided by nurse plants in these environments can attenuate the patterns of local adaptation among plants benefiting

  4. Population Genetic Structure of a Widespread Bat-Pollinated Columnar Cactus.

    PubMed

    Bustamante, Enriquena; Búrquez, Alberto; Scheinvar, Enrique; Eguiarte, Luis Enrique

    2016-01-01

    Bats are the main pollinators and seed dispersers of Stenocereus thurberi, a xenogamous columnar cactus of northwestern Mexico and a good model to illustrate spatial dynamics of gene flow in long-lived species. Previous studies in this cactus showed differences among populations in the type and abundance of pollinators, and in the timing of flowering and fruiting. In this study we analyzed genetic variability and population differentiation among populations. We used three primers of ISSR to analyze within and among populations genetic variation from eight widely separated populations of S. thurberi in Sonora, Mexico. Sixty-six out of 99 of the ISSR bands (P = 66.7%) were polymorphic. Total heterozygosity for all populations sampled revealed high genetic diversity (Hsp = 0.207, HBT = 0.224). The AMOVA showed that most of the genetic variation was within populations (80.5%). At the species level, estimates of population differentiation, θ = 0.175 and θB = 0.194, indicated moderate gene flow among populations. The absence of a significant correlation between genetic and geographic distances indicated little isolation by geographic distance. The large genetic variation and diversity found in S. thurberi is consistent with its open reproductive system and the high mobility of bats, a major pollinator. However, small changes in number or kind of pollinators and seed dispersal agents, in the directionality of migratory routes, and/or in the timing of flowering and fruiting among populations, can critically affect gene flow dynamics.

  5. Population Genetic Structure of a Widespread Bat-Pollinated Columnar Cactus

    PubMed Central

    Bustamante, Enriquena; Búrquez, Alberto; Scheinvar, Enrique; Eguiarte, Luis Enrique

    2016-01-01

    Bats are the main pollinators and seed dispersers of Stenocereus thurberi, a xenogamous columnar cactus of northwestern Mexico and a good model to illustrate spatial dynamics of gene flow in long-lived species. Previous studies in this cactus showed differences among populations in the type and abundance of pollinators, and in the timing of flowering and fruiting. In this study we analyzed genetic variability and population differentiation among populations. We used three primers of ISSR to analyze within and among populations genetic variation from eight widely separated populations of S. thurberi in Sonora, Mexico. Sixty-six out of 99 of the ISSR bands (P = 66.7%) were polymorphic. Total heterozygosity for all populations sampled revealed high genetic diversity (Hsp = 0.207, HBT = 0.224). The AMOVA showed that most of the genetic variation was within populations (80.5%). At the species level, estimates of population differentiation, θ = 0.175 and θB = 0.194, indicated moderate gene flow among populations. The absence of a significant correlation between genetic and geographic distances indicated little isolation by geographic distance. The large genetic variation and diversity found in S. thurberi is consistent with its open reproductive system and the high mobility of bats, a major pollinator. However, small changes in number or kind of pollinators and seed dispersal agents, in the directionality of migratory routes, and/or in the timing of flowering and fruiting among populations, can critically affect gene flow dynamics. PMID:27015281

  6. Population Genetic Structure of a Widespread Bat-Pollinated Columnar Cactus.

    PubMed

    Bustamante, Enriquena; Búrquez, Alberto; Scheinvar, Enrique; Eguiarte, Luis Enrique

    2016-01-01

    Bats are the main pollinators and seed dispersers of Stenocereus thurberi, a xenogamous columnar cactus of northwestern Mexico and a good model to illustrate spatial dynamics of gene flow in long-lived species. Previous studies in this cactus showed differences among populations in the type and abundance of pollinators, and in the timing of flowering and fruiting. In this study we analyzed genetic variability and population differentiation among populations. We used three primers of ISSR to analyze within and among populations genetic variation from eight widely separated populations of S. thurberi in Sonora, Mexico. Sixty-six out of 99 of the ISSR bands (P = 66.7%) were polymorphic. Total heterozygosity for all populations sampled revealed high genetic diversity (Hsp = 0.207, HBT = 0.224). The AMOVA showed that most of the genetic variation was within populations (80.5%). At the species level, estimates of population differentiation, θ = 0.175 and θB = 0.194, indicated moderate gene flow among populations. The absence of a significant correlation between genetic and geographic distances indicated little isolation by geographic distance. The large genetic variation and diversity found in S. thurberi is consistent with its open reproductive system and the high mobility of bats, a major pollinator. However, small changes in number or kind of pollinators and seed dispersal agents, in the directionality of migratory routes, and/or in the timing of flowering and fruiting among populations, can critically affect gene flow dynamics. PMID:27015281

  7. Daily to decadal patterns of precipitation, humidity, and photosynthetic physiology recorded in the spines of the columnar cactus, Carnegiea gigantea

    NASA Astrophysics Data System (ADS)

    English, Nathan B.; Dettman, David L.; Sandquist, Darren R.; Williams, David G.

    2010-06-01

    Isotopic analyses of cactus spines grown serially from the apex of long-lived columnar cactuses may be useful for climatological and ecological studies if time series can be reliably determined from spines. To characterize the timescales over which spines may record this information, we measured spine growth in saguaro cactus over days, months, and years with time-lapse photography, periodic marking, and postbomb radiocarbon dating and then analyzed isotopic variability over these same timescales and compared these measurements to local climate. We used daily increments of growth, visible as transverse bands of light and dark tissue in spines, as chronometers to develop diurnally resolved δ13C and δ18O records from three spines grown in series over a 70 day period. We also constructed a 22 year record of δ13C variations from spine tips arranged in chronological sequence along the side of a 4 m tall, single-stemmed saguaro. We evaluated two mechanisms potentially responsible for daily, weekly, and annual variability in δ13C values of spines; both related to vapor pressure deficit (VPD). Our data suggest that stomatal conductance is unlikely to be the determinant of δ13C variation in spines. We suggest that either VPD-induced changes in the balance of nighttime- and daytime-assimilated CO2 or mesophyll-limited diffusion of CO2 at night are the most likely determinant of δ13C variation in spines. Intra-annual and interannual variability of δ18O in spine tissue appears to be controlled by the mass balance of 18O-depleted water taken up after rain events and evaporative enrichment of 18O in tissue water between rains. We were able to estimate the annual growth and areole generation rate of a saguaro cactus from its 22 yearlong isotopic record because VPD, rainfall, and evaporation exhibit strong annual cycles in the Sonoran Desert and these variations are recorded in the oxygen and carbon isotope ratios of spines.

  8. Cactus

    SciTech Connect

    Sexton, R.L.

    1983-03-01

    The CACTUS project (computer-aided control, tracking, and updating system) was initiated by the Bendix Kansas City Division to address specific work-in-process problems encountered in a cable department. Since then, the project has been expanded to additional electrical manufacturing departments because of potential productivity gains from the system. The philosophy of CACTUS is to add an element of distributed data proessing to the centralized data processing system currently in use for control of work in process. Under this system, the existing chain of communications between the host computer and the CRT terminals in a department is severed. A mini-computer established in the department communicates directly with the central system, and departmental communication is then established with the mini-computer. The advantages, disadvantages, operation performance, and economics of the system are discussed.

  9. Crassulacean acid metabolism photosynthesis in columnar cactus seedlings during ontogeny: the effect of light on nocturnal acidity accumulation and chlorophyll fluorescence.

    PubMed

    Hernández-González, Olivia; Villarreal, Oscar Briones

    2007-08-01

    Columnar cacti have been traditionally classified as crassulacean acid metabolism (CAM) plants, though recent research indicates some cactus seedlings employ the C(3) pathway. To verify this last result, we measured acidity fluctuations for five columnar and one globular cactus species in seedlings from 1 to 48 d old after experimental exposure to 60% and 30% full sunlight, and in adult plants in the field. Using light-response curves of chlorophyll fluorescence, we determined photosynthetic efficiency (ΔF/Fm'), maximum electron transport rate (ETR(max)) and saturating photosynthetically active photon flux density (PPFD(sat)). All seedlings used the CAM pathway from their first day of development, and increases in nocturnal acidity depended on species, light treatment, and age. The CAM pathway was also found in adult plants. Cactus seedlings were able to acclimatize to light conditions by making photochemical adjustments, mainly by modifying the level of light at which photosystem II is saturated (PPFD(sat)). The presence of CAM in the seedlings of columnar cacti increases water-use efficiency and reduces the risk of photoinhibition. This could favor survival in the highly variable light levels characteristic of the desert environments of columnar cacti.

  10. Dating Cactus: Annual and Sub-annual Variations of Oxygen-18, Carbon-13 and Radiocarbon in Spines of a Columnar Cactus, Carnegiea gigantea.

    NASA Astrophysics Data System (ADS)

    Dettman, D. L.; English, N. B.; Sandquist, D. R.; Williams, D. G.

    2006-12-01

    We measured δ18O, δ13C and F14C of spines from a long-lived columnar cactus, Carnegiea gigantea (saguaro), to resolve a record of plant physiological responses to annual and sub-annual climate variation in the eastern Sonoran Desert. Spines grow from the apex of the cactus and are arranged serially along the side of the cactus oldest at the base, youngest at the apex. To establish the age of the spine series, we measured F14C of spines collected at 8 different heights from the apex (3.77 m) to the base of a naturally occurring saguaro. These spines yielded fractions of modern carbon (F14C) from 0.9679 and 1.5537, indicating the presence of carbon in spine tissue derived from atmospheric nuclear testing. We used the F14C of spine tissue to calculate the year of spine emergence for each of the 11 spines, assuming minimal re-allocation of stored carbon to growing spines. At the same 8 heights, we interpolated the date of spine emergence from observed height measurements made between 1964 and 2002. A very strong positive correlation (linear regression, r2 = 0.99, P < 0.0001) between the F14C age of spines and ages determined from direct height measurements was observed, with a two year offset suggesting incorporation of carbon from fossil fuel combustion sources in the Tucson basin. Additionally, spine tips from 97 spines collected serially from the top half of the same saguaro (between 1.77 and 3.50 m) and representing ~15 years of growth, yielded δ18O variations in spine bulk organic material from 38° to 50° (VSMOW) and in δ13C from ° to 11.5° (VPDB). The δ18O and δ13C values were positively correlated over the entire record (linear regression, r2 = 0.22, P < 0.0001). These variations occurred at or near an annual frequency. The most negative δ18O and δ13C values in bulk spine organic material from the naturally occurring cactus were observed in spines grown shortly following the 1983 and 1993 strong El Niño winter precipitation events in Tucson

  11. Effect of habitat disturbance on pollination biology of the columnar cactus Stenocereus quevedonis at landscape-level in central Mexico.

    PubMed

    Rodríguez-Oseguera, A G; Casas, A; Herrerías-Diego, Y; Pérez-Negrón, E

    2013-05-01

    Stenocereus quevedonis ('pitire') is a columnar cactus endemic to central Mexico, grown for its edible fruit. Phenology, pollination biology and behaviour of flower visitors of this species were compared in six conserved and disturbed sites, hypothesising that: (i) pitire pollination is self-incompatible, requiring animal vectors; (ii) higher incidence of radiation on plants in cleared forest may lead to a higher number of flowers per pitire plant and longer blooming season, and disturbing and differential spatial availability of flower resources may determine differential attraction of pollinators to conserved and disturbed areas; (iii) if pitire pollination system is specialised, reproductive success would decrease with pollinator scarcity, or other species may substitute for main pollinators. In all sites, pitire reproduction started in January, flowering peak occurring in April, anthesis duration was 15 h and predominantly nocturnal (9 h), pollen was released at 23:00 h, nectar was produced throughout anthesis, and breeding system was self-incompatible. Flower production per plant was similar in disturbed and conserved sites, but flower availability was higher (because of higher tree density) and longer in disturbed sites. Pollination is nocturnal, the most frequent legitimate pollinator being the bat Leptonycteris yerbabuenae; diurnal pollination is rare but possible, carried out by bee species. Fruit and seed set in control and nocturnal pollination treatments at disturbed sites were higher than in conserved sites. Frequency of L. yerbabuenae visits was similar among site types, but more visits of complementary nocturnal and diurnal pollinators were recorded in disturbed sites, which could explain differences in reproductive success.

  12. Direct and indirect estimates of gene flow among wild and managed populations of Polaskia chichipe, an endemic columnar cactus in Central Mexico.

    PubMed

    Otero-Arnaiz, Adriana; Casas, Alejandro; Hamrick, James L

    2005-12-01

    Microsatellite markers were used to obtain direct and indirect estimates of gene flow in populations of Polaskia chichipe under different management regimes, in order to understand the genetic consequences of gene flow in the evolutionary process of domestication. P. chichipe is a columnar cactus endemic to the Tehuacan Valley, Central Mexico, and has come under domestication for its edible fruit. Morphological, phenological, physiological, and reproductive differences, apparently attributable to artificial selection, exist between wild and managed populations, which grow sympatrically. However, strong gene flow may counteract the effects of this selection. In this study, we used paternity analysis to demonstrate that although most of the pollinations occur among individuals within the same population at distances < 40 m, pollen flow from other populations is considerable (27 +/- 5%). Heterogeneity in pollen clouds sampled by mother plants (FST = 0.12) indicated nonrandom mating, which is probably due to temporal heterogeneity in pollen movement. Spatial structure on local and regional scales is consistent with an isolation-by-distance model. The similarity of indirect, direct and demographic estimates of neighbourhood size (74-250 individuals) suggests that this genetic structure is representative of an equilibrium state. These results suggest that traditional management practices have conserved the genetic resources of this species in situ, but also that gene flow is counteracting the effect of domestication to some degree. We discuss our results in the general context of genetic exchange between cultivated and wild populations during the domestication process.

  13. Cactus: a medicinal food.

    PubMed

    Shetty, Anoop A; Rana, M K; Preetham, S P

    2012-10-01

    With excellent quality and flavour of fresh fruits, young leaves of cactus serve as nutritious vegetable and salad dish and the immature fruits for making mock-gherkins. Cactus, with high water use efficiency produce forage for animals, vegetables, and fruits with 14% glucose. Traditionally cactus used as a valuable health supporting nutrient and it also has applications in pharmaceutical industries. Cactus with number of uses has immense potential to be the food of future. PMID:24082263

  14. Identification and ecology of bacterial communities associated with necroses of three cactus species.

    PubMed

    Foster, J L; Fogleman, J C

    1993-01-01

    To compare the bacterial communities residing in necrotic tissues of columnar cacti of the Sonoran Desert, isolates from 39 organ pipe, 19 saguaro, and 16 senita cacti were obtained. The isolates were clustered into 28 conspecific groups on the basis of their fatty acid profiles. The distributions of the individual bacterial isolates varied among cactus species. Seven of the 28 species groups were unique to a particular cactus species, whereas 8 species groups were found in all three cacti. The effective number of bacterial species for each cactus species was positively correlated with both the chemical complexity and glucose concentration of the plant tissues. The effective number of bacterial species and bacterial distribution patterns were compared with those known for communities of cactophilic yeasts. The observed bacterial distribution patterns are most likely due to differences in the chemical compositions of the three cactus species. PMID:8439142

  15. Cactus spine injuries.

    PubMed

    Lindsey, D; Lindsey, W E

    1988-07-01

    Cactus spines produce injuries whose clinical significance is loosely in inverse proportion to the dimensions of the spine. Long and medium spines of saguaro and barrel cacti seldom result in embedded fragments, but when they do they are difficult to locate and remove. Other medium spines, those of prickly pear and cholla, are a nuisance but they can be removed readily by traction, as can the smaller spines (glochids) of the prickly pear. The very small spines (also glochids) of the polka dot or bunny's ear cactus (Opuntia microdasys) and the beavertail cactus (Opuntia basilaris) offer the most frustrating problem of all, but can be peeled off with a dried film of a professional facial gel. PMID:3390256

  16. Sarcocystis-associated meningoencephalitis in a bald eagle (Haliaeetus leucocephalus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protozoal meningoencephalitis is rare in raptors. An adult female bald eagle (Haliaeetus leucocephalus) with progressive neurological signs was euthanized after several months of treatment. The predominant histological lesion was lymphoplasmacytic and histiocytic meningoencephalitis involving the ...

  17. Scaling in Columnar Joints

    NASA Astrophysics Data System (ADS)

    Morris, Stephen

    2007-03-01

    Columnar jointing is a fracture pattern common in igneous rocks in which cracks self-organize into a roughly hexagonal arrangement, leaving behind an ordered colonnade. We report observations of columnar jointing in a laboratory analog system, desiccated corn starch slurries. Using measurements of moisture density, evaporation rates, and fracture advance rates, we suggest an advective-diffusive system is responsible for the rough scaling behavior of columnar joints. This theory explains the order of magnitude difference in scales between jointing in lavas and in starches. We investigated the scaling of average columnar cross-sectional areas in experiments where the evaporation rate was fixed using feedback methods. Our results suggest that the column area at a particular depth is related to both the current conditions, and hysteretically to the geometry of the pattern at previous depths. We argue that there exists a range of stable column scales allowed for any particular evaporation rate.

  18. Fatal toxoplasmosis in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Szabo, K A; Mense, M G; Lipscomb, T P; Felix, K J; Dubey, J P

    2004-08-01

    Toxoplasma gondii tachyzoites were identified in the myocardium of a bald eagle (Haliaeetus leucocephalus) that died of necrotizing myocarditis. The diagnosis was confirmed by immunohistochemical staining with T. gondii-specific polyclonal antibodies. This is a new host record for T. gondii.

  19. Erysipelothrix rhusiopathiae infection in a captive bald eagle (Haliaeetus leucocephalus)

    USGS Publications Warehouse

    Franson, J.C.; Galbreath, Elizabeth J.; Wiemeyer, Stanley N.; Abell, John M.

    1994-01-01

    An adult bald eagle (Haliaeetus leucocephalus) kept in captivity for nearly 7 yr at the Patuxent Wildlife Research Center, Laurel, Maryland, died suddenly with gross and microscopic lesions characteristic of septicemia. Erysipelothrix rhusiopathiae was isolated from the liver. Fish comprised part of the bird's diet and may have been the source of the organism.

  20. Betalains from Christmas cactus.

    PubMed

    Kobayashi, N; Schmidt, J; Nimtz, M; Wray, V; Schliemann, W

    2000-06-01

    The presence of 14 betalain pigments have been detected by their characteristic spectral properties in flower petals of Christmas cactus (Schlumbergera x buckleyi). Along with the known vulgaxanthin I, betalamic acid, betanin and phyllocactin (6'-O-malonylbetanin), the structure of a new phyllocactin-derived betacyanin was elucidated by various spectroscopic techniques and carbohydrate analyses as betanidin 5-O-(2'-O-beta-D-apiofuranosyl-6'-O-malonyl)-beta-D-glucopyranosid e. Among the more complex betacyanins occurring in trace amounts, the presence of a new diacylated betacyanin ¿betanidin 5-O-[(5"-O-E-feruloyl)-2'-O-beta-D- apiofuranosyl-6'-O-malonyl)]-beta-D-glucopyranoside¿ has been ascertained. Furthermore, the accumulation of betalains during flower development and their pattern in different organs of the flower has been examined.

  1. Columnar lined Barrett's oesophagus.

    PubMed

    Sharma, Neel; Ho, Khek Yu

    2015-12-01

    Over the past few years, the definition of Barrett's oesophagus has altered with no real agreement on histological understanding. This article highlights the increasing confusion regarding Barrett's oesophagus with a focus on the all-too-frequently ignored aspect of the columnar lined oesophagus.

  2. Cactus: HPC infrastructure and programming tools

    NASA Astrophysics Data System (ADS)

    Collaborative Effort

    2011-02-01

    Cactus provides computational scientists and engineers with a collaborative, modular and portable programming environment for parallel high performance computing. Cactus can make use of many other technologies for HPC, such as Samrai, HDF5, PETSc and PAPI, and several application domains such as numerical relativity, computational fluid dynamics and quantum gravity are developing open community toolkits for Cactus.

  3. Flash electroretinography in the bald eagle (Haliaeetus leucocephalus).

    PubMed

    Kuhn, Sonia E; Hendrix, Diane V H; Sims, Michael H; Ward, Daniel A; Jones, Michael P; Baine, Katherine H

    2014-09-01

    Photopic and scotopic flash electroretinograms (fERGs) were done on 12 adult captive anesthetized bald eagles (Haliaeetus leucocephalus) following a complete ophthalmic exam. The b-wave amplitude in the bald eagle exceeds that seen in other species when using a similar protocol. This data may be used clinically as a reference for bald eagles undergoing fERG evaluation for retinal disease or as a preoperative screening tool before phacoemulsification.

  4. Flash electroretinography in the bald eagle (Haliaeetus leucocephalus).

    PubMed

    Kuhn, Sonia E; Hendrix, Diane V H; Sims, Michael H; Ward, Daniel A; Jones, Michael P; Baine, Katherine H

    2014-09-01

    Photopic and scotopic flash electroretinograms (fERGs) were done on 12 adult captive anesthetized bald eagles (Haliaeetus leucocephalus) following a complete ophthalmic exam. The b-wave amplitude in the bald eagle exceeds that seen in other species when using a similar protocol. This data may be used clinically as a reference for bald eagles undergoing fERG evaluation for retinal disease or as a preoperative screening tool before phacoemulsification. PMID:25314846

  5. How Nectar-Feeding Bats Localize their Food: Echolocation Behavior of Leptonycteris yerbabuenae Approaching Cactus Flowers

    PubMed Central

    Koblitz, Jens C.; Fleming, Theodore H.; Medellín, Rodrigo A.; Kalko, Elisabeth K. V.; Schnitzler, Hans-Ulrich; Tschapka, Marco

    2016-01-01

    Nectar-feeding bats show morphological, physiological, and behavioral adaptations for feeding on nectar. How they find and localize flowers is still poorly understood. While scent cues alone allow no precise localization of a floral target, the spatial properties of flower echoes are very precise and could play a major role, particularly at close range. The aim of this study is to understand the role of echolocation for classification and localization of flowers. We compared the approach behavior of Leptonycteris yerbabuenae to flowers of a columnar cactus, Pachycereus pringlei, to that to an acrylic hollow hemisphere that is acoustically conspicuous to bats, but has different acoustic properties and, contrary to the cactus flower, present no scent. For recording the flight and echolocation behaviour we used two infrared video cameras under stroboscopic illumination synchronized with ultrasound recordings. During search flights all individuals identified both targets as a possible food source and initiated an approach flight; however, they visited only the cactus flower. In experiments with the acrylic hemisphere bats aborted the approach at ca. 40–50 cm. In the last instant before the flower visit the bats emitted a long terminal group of 10–20 calls. This is the first report of this behaviour for a nectar-feeding bat. Our findings suggest that L. yerbabuenae use echolocation for classification and localization of cactus flowers and that the echo-acoustic characteristics of the flower guide the bats directly to the flower opening. PMID:27684373

  6. Are cactus growth forms related to germination responses to light? A test using Echinopsis species

    NASA Astrophysics Data System (ADS)

    Ortega-Baes, Pablo; Aparicio-González, Mónica; Galíndez, Guadalupe; del Fueyo, Patricia; Sühring, Silvia; Rojas-Aréchiga, Mariana

    2010-05-01

    In this study, we investigated the effect of light regimen (white light vs. darkness) on the germination of 12 species of the Echinopsis genus (tribe Trichocereeae, Cactaceae). This genus presents a variety of growth forms and relatively small and uniform seed size. These traits allowed us to test, within the same linage and removing seed mass effect, the hypothesis that the germination response to light (indifferent to light or positive photoblastic) is related to growth form. Our results reject this hypothesis since no seeds germinated in darkness, so all of the species can be classified as being positively photoblastic. The proportion of seed germination with white light was significantly different among cactus growth forms. Columnar cacti (arborescent, creeping and short) showed a greater proportion of seed germination than barrel and globose cacti. The germination rate differed among growth forms and species. At constant temperatures, creeping columnar cacti presented a significantly higher germination rate than the other growth forms. With alternating temperatures, columnar cacti showed higher germination rates than the other growth forms. The low proportion of seeds that germinated for some species indicates that they show seed dormancy. Our results suggest that germination responses to light in the cactus family could be related to seed mass and phylogenetic constraints.

  7. Mycobacteriosis in an American bald eagle (Haliaeetus leucocephalus).

    PubMed

    Hoenerhoff, Mark; Kiupel, Matti; Sikarskie, James; Bolin, Carole; Simmons, Heather; Fitzgerald, Scott

    2004-01-01

    Avian mycobacteriosis is an important disease in companion, captive, exotic, and wild birds worldwide. Mycobacterium avium is the most widely distributed and pathogenic organism causing tuberculous lesions in birds. Multiple factors including age, stress, immune status, and preexisting disease determine the pathogenicity of M. avium, and the disease can manifest itself in a variety of forms. Mycobacteriosis can cause severe losses in zoo aviaries, including the loss of rare and endangered bird species. We report a case of systemic avian mycobacteriosis in an adult, free-living male American bald eagle (Haliaeetus leucocephalus) that presented to the Diagnostic Center for Population and Animal Health in November 2003.

  8. Helminth parasites of the bald eagle, Haliaeetus leucocephalus, in Florida

    USGS Publications Warehouse

    Kinsella, J.M.; Foster, Garry W.; Cole, Rebecca A.; Forrester, Donald J.

    1998-01-01

    Twenty species of helminths (9 trematodes, 9 nematodes, and 2 acanthocephalans), including 9 new host records, were collected from 40 bald eagles (Haliaeetus leucocephalus) from Florida. Intensities of infection were low and no lesions were attributed to the parasites. No species were considered specialists in bald eagles; 5 species were considered raptor generalists and the remainder, generalists in other orders of fish-eating birds. An undescribed species of Hamatospiculum was found in 3 birds. Most of the common helminths were acquired from eating fish intermediate hosts.

  9. Functional trade-offs in succulent stems predict responses to climate change in columnar cacti.

    PubMed

    Williams, David G; Hultine, Kevin R; Dettman, David L

    2014-07-01

    Columnar cacti occur naturally in many habitats and environments in the Americas but are conspicuously dominant in very dry desert regions. These majestic plants are widely regarded for their cultural, economic, and ecological value and, in many ecosystems, support highly diverse communities of pollinators, seed dispersers, and frugivores. Massive amounts of water and other resources stored in the succulent photosynthetic stems of these species confer a remarkable ability to grow and reproduce during intensely hot and dry periods. Yet many columnar cacti are potentially under severe threat from environmental global changes, including climate change and loss of habitat. Stems in columnar cacti and other cylindrical-stemmed cacti are morphologically diverse; stem volume-to-surface area ratio (V:S) across these taxa varies by almost two orders of magnitude. Intrinsic functional trade-offs are examined here across a broad range of V:S in species of columnar cacti. It is proposed that variation in photosynthetic gas exchange, growth, and response to stress is highly constrained by stem V:S, establishing a mechanistic framework for understanding the sensitivity of columnar cacti to climate change and drought. Specifically, species that develop stems with low V:S, and thus have little storage capacity, are expected to express high mass specific photosynthesis and growth rates under favourable conditions compared with species with high V:S. But the trade-off of having little storage capacity is that low V:S species are likely to be less tolerant of intense or long-duration drought compared with high V:S species. The application of stable isotope measurements of cactus spines as recorders of growth, water relations, and metabolic responses to the environment across species of columnar cacti that vary in V:S is also reviewed. Taken together, our approach provides a coherent theory and required set of observations needed for predicting the responses of columnar cacti to

  10. Disseminated mycobacteriosis in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Heatley, J Jill; Mitchell, Mark M; Roy, Alma; Cho, Doo Youn; Williams, Diana L; Tully, Thomas N

    2007-09-01

    A mature bald eagle (Haliaeetus leucocephalus) was diagnosed with mycobacterial infection after being presented for an inability to fly, emaciation, and a swelling of the left tibiotarsal-tarso metatarsal joint. Results of a complete blood cell count revealed a persistent, marked leukocytosis, with heterophilia, monocytosis, and anemia. Radiographs revealed lysis of the left distal tibiotarsus and soft-tissue swelling around the left tibiotarsal-tarsometatarsal joint, multiple pulmonary opacities, and an enlarged liver. Endoscopic evaluation and biopsy of caseated material within the left caudal coelom revealed acid-fast organisms. The eagle was euthanatized, and results of necropsy and histologic evaluation revealed caseated granulomas of the intestine, lungs, air sacs, and subcutaneous regions of the hock. Results of culture, a polymerase chain reaction testing, and direct deoxyribonucleic acid (DNA) sequencing for mycobacterial 16S ribosomal ribonucleic acid DNA determined this organism most likely to be Mycobacterium avium.

  11. Mercury contamination in Idaho bald eagles, Haliaeetus leucocephalus.

    PubMed

    Bechard, Marc J; Perkins, Dusty N; Kaltenecker, Gregory S; Alsup, Steve

    2009-11-01

    Because mercury contamination is potentially threatening to bald eagle (Haliaeetus leucocephalus) populations, we collected molted feathers at nests to determine the level of contamination in bald eagles in the state of Idaho, USA. Eagle feathers contained measurable amounts of cadmium (Cd), chromium (Cr), selenium (Se), lead (Pb), as well as mercury (Hg). Cadmium, Cr, Se, and Pb levels averaged 0.17, 4.68, 2.02, and 1.29 mg/kg dry weight, respectively, and were at or below concentrations indicated as causing reproductive failure in bald eagles. Mercury contamination was found to be the highest averaging 18.74 mg/kg dry weight. Although a concentration of only 7.5 mg/kg dry weight Hg in bird feathers can cause reduced productivity and even sterility, all of the eagles we sampled bred successfully and the population of bald eagles continues to grow annually throughout the state.

  12. Absolute polycythemia in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Fernandes, Andreia F; Fenton, Heather; Martinson, Shannon; Desmarchelier, Marion; Ferrell, Shannon T

    2014-12-01

    An approximately 6-mo-old female bald eagle (Haliaeetus leucocephalus) was presented for an inability to fly and bilateral drooped wings. Pectoral muscle atrophy with a moderate polycythemia was present. Over the course of 3 wk, there were no improvements in flight capacity, although the bird gained substantial weight. Further investigation revealed a prominent cyanosis that was responsive to oxygen therapy, a chronic respiratory acidosis with hypoxia, a cardiac murmur, and a persistent polycythemia. No obvious antemortem etiology for the clinical findings was discovered on computerized tomography, angiography, or echocardiography. The bird was euthanatized as a result of the poor prognosis. Necropsy and histopathology revealed no significant cardiovascular or pulmonary pathology. No myopathy was evident on electron microscopy of formalin-fixed tissues. Based on these diagnostics, a neuromuscular disorder is suspected as the cause for the blood gas abnormalities, with a resulting polycythemia from the hypoxia.

  13. Acanthocephala of the bald eagle (Haliaeetus leucocephalus) in North America.

    PubMed

    Richardson, D J; Cole, R A

    1997-06-01

    Examination of bald eagles (Haliaeetus leucocephalus) collected from several locations in North America contributed new information concerning the acanthocephalan fauna of this host. Representatives of Arythmorhynchus brevis, representing a new host record, were collected from eagles in Florida, New Hampshire, and Wisconsin. Plagiorhynchus sp. was collected from an eagle in Florida. Corynosoma strumosum was collected from an eagle in Alaska. Andracantha phalacrocoracis, representing a new host record, was collected from an eagle in Alaska. Southwellina hispida, representing a new host record, was collected from eagles in Maine and Virginia. The occurrence of gravid or mature females of A. brevis, Plagiorhynchus sp., and S. hispida suggests that the bald eagle may serve as a competent definitive host for these species.

  14. Mercury contamination in Idaho bald eagles, Haliaeetus leucocephalus.

    PubMed

    Bechard, Marc J; Perkins, Dusty N; Kaltenecker, Gregory S; Alsup, Steve

    2009-11-01

    Because mercury contamination is potentially threatening to bald eagle (Haliaeetus leucocephalus) populations, we collected molted feathers at nests to determine the level of contamination in bald eagles in the state of Idaho, USA. Eagle feathers contained measurable amounts of cadmium (Cd), chromium (Cr), selenium (Se), lead (Pb), as well as mercury (Hg). Cadmium, Cr, Se, and Pb levels averaged 0.17, 4.68, 2.02, and 1.29 mg/kg dry weight, respectively, and were at or below concentrations indicated as causing reproductive failure in bald eagles. Mercury contamination was found to be the highest averaging 18.74 mg/kg dry weight. Although a concentration of only 7.5 mg/kg dry weight Hg in bird feathers can cause reduced productivity and even sterility, all of the eagles we sampled bred successfully and the population of bald eagles continues to grow annually throughout the state. PMID:19690789

  15. Absolute polycythemia in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Fernandes, Andreia F; Fenton, Heather; Martinson, Shannon; Desmarchelier, Marion; Ferrell, Shannon T

    2014-12-01

    An approximately 6-mo-old female bald eagle (Haliaeetus leucocephalus) was presented for an inability to fly and bilateral drooped wings. Pectoral muscle atrophy with a moderate polycythemia was present. Over the course of 3 wk, there were no improvements in flight capacity, although the bird gained substantial weight. Further investigation revealed a prominent cyanosis that was responsive to oxygen therapy, a chronic respiratory acidosis with hypoxia, a cardiac murmur, and a persistent polycythemia. No obvious antemortem etiology for the clinical findings was discovered on computerized tomography, angiography, or echocardiography. The bird was euthanatized as a result of the poor prognosis. Necropsy and histopathology revealed no significant cardiovascular or pulmonary pathology. No myopathy was evident on electron microscopy of formalin-fixed tissues. Based on these diagnostics, a neuromuscular disorder is suspected as the cause for the blood gas abnormalities, with a resulting polycythemia from the hypoxia. PMID:25632692

  16. Disseminated mycobacteriosis in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Heatley, J Jill; Mitchell, Mark M; Roy, Alma; Cho, Doo Youn; Williams, Diana L; Tully, Thomas N

    2007-09-01

    A mature bald eagle (Haliaeetus leucocephalus) was diagnosed with mycobacterial infection after being presented for an inability to fly, emaciation, and a swelling of the left tibiotarsal-tarso metatarsal joint. Results of a complete blood cell count revealed a persistent, marked leukocytosis, with heterophilia, monocytosis, and anemia. Radiographs revealed lysis of the left distal tibiotarsus and soft-tissue swelling around the left tibiotarsal-tarsometatarsal joint, multiple pulmonary opacities, and an enlarged liver. Endoscopic evaluation and biopsy of caseated material within the left caudal coelom revealed acid-fast organisms. The eagle was euthanatized, and results of necropsy and histologic evaluation revealed caseated granulomas of the intestine, lungs, air sacs, and subcutaneous regions of the hock. Results of culture, a polymerase chain reaction testing, and direct deoxyribonucleic acid (DNA) sequencing for mycobacterial 16S ribosomal ribonucleic acid DNA determined this organism most likely to be Mycobacterium avium. PMID:18087937

  17. Acanthocephala of the bald eagle (Haliaeetus leucocephalus) in North America

    USGS Publications Warehouse

    Richardson, D.J.; Cole, R.A.

    1997-01-01

    Examination of bald eagles (Haliaeetus leucocephalus) collected from several locations in North America contributed new information concerning the acanthocephalan fauna of this host. Representatives of Arythmorhynchus brevis, representing a new host record, were collected from eagles in Florida, New Hampshire, and Wisconsin. Plagiorhynchus sp. was collected from an eagle in Florida. Corynosoma strumosum was collected from an eagle in Alaska. Andracantha phalacrocoracis, representing a new host record, was collected from an eagle in Alaska. Southwellina hispida, representing a new host record, was collected from eagles in Maine and Virginia. The occurrence of gravid or mature females of A. brevis, Plagiorhynchus sp., and S. hispida suggests that the bald eagle may serve as a competent definitive host for these species.

  18. CACTUS SPRING ROADLESS AREA, CALIFORNIA.

    USGS Publications Warehouse

    Matti, Jonathan C.; Kuizon, Lucia

    1984-01-01

    Geologic, geochemical, and geophysical studies together with a review of historic mining and prospecting activities indicate that the Cactus Spring Roadless Area in California has little promise for the occurrence of mineral or energy resources. Marble bodies occur in the northern part of the roadless area and are possible resources for building stone, crushed and quarried aggregate, and lime and magnesium for Portland cement and industrial applications. It is recommended that the terrane of marble be mapped and sampled carefully in order to evaluate the quantity and quality of the carbonate resources.

  19. Bacteria Associated with Copestylum (Diptera, Syrphidae) Larvae and Their Cactus Host Isolatocereus dumortieri

    PubMed Central

    Martínez-Falcón, Ana Paola; Durbán, Ana; Latorre, Amparo; Antón, Josefa; Marcos-García, María de los Ángeles

    2011-01-01

    We describe the gut bacterial diversity inhabiting two saprophagous syrphids and their breeding substrate (decayed tissues of the columnar cactus Isolatocereus dumortieri). We analyzed the gut microbiota of Copestylum latum (scooping larvae that feed on decayed cactus tissues) and Copestylum limbipenne (whose larvae can also feed on semiliquid tissues) using molecular techniques. DNA was extracted from larval guts and cactus tissues. The V1-V3 region of the 16S rRNA genes was amplified and sequenced. A total of 31079 sequences were obtained. The main findings are: C. limbipenne is dominated by several Enterobacteriaceae, including putative nitrogen-fixing genera and pectinolitic species and some denitrifying species, whereas in C. latum unclassified Gammaproteobacteria predominate. Decayed tissues have a dominant lactic acid bacterial community. The bacterial communities were more similar between larval species than between each larva and its breeding substrate. The results suggest that the gut bacterial community in these insects is not strongly affected by diet and must be dependent on other factors, such as vertical transmission, evolutionary history and host innate immunity. PMID:22132101

  20. Transcriptional variation associated with cactus host plant adaptation in Drosophila mettleri populations.

    PubMed

    Hoang, Kim; Matzkin, Luciano M; Bono, Jeremy M

    2015-10-01

    Although the importance of host plant chemistry in plant-insect interactions is widely accepted, the genetic basis of adaptation to host plants is not well understood. Here, we investigate transcriptional changes associated with a host plant shift in Drosophila mettleri. While D. mettleri is distributed mainly throughout the Sonoran Desert where it specializes on columnar cacti (Carnegiea gigantea and Pachycereus pringleii), a population on Santa Catalina Island has shifted to chemically divergent coastal prickly pear cactus (Opuntia littoralis). We compared gene expression of larvae from the Sonoran Desert and Santa Catalina Island when reared on saguaro (C. gigantea), coastal prickly pear and laboratory food. Consistent with expectations based on the complexity and toxicity of cactus relative to laboratory food, within-population comparisons between larvae reared on these food sources revealed transcriptional differences in detoxification and other metabolic pathways. The majority of transcriptional differences between populations on the cactus hosts were independent of the rearing environment and included a disproportionate number of genes involved in processes relevant to host plant adaptation (e.g. detoxification, central metabolism and chemosensory pathways). Comparisons of transcriptional reaction norms between the two populations revealed extensive shared plasticity that likely allowed colonization of coastal prickly pear on Santa Catalina Island. We also found that while plasticity may have facilitated subsequent adaptive divergence in gene expression between populations, the majority of genes that differed in expression on the novel host were not transcriptionally plastic in the presumed ancestral state. PMID:26384860

  1. Transcriptional variation associated with cactus host plant adaptation in Drosophila mettleri populations.

    PubMed

    Hoang, Kim; Matzkin, Luciano M; Bono, Jeremy M

    2015-10-01

    Although the importance of host plant chemistry in plant-insect interactions is widely accepted, the genetic basis of adaptation to host plants is not well understood. Here, we investigate transcriptional changes associated with a host plant shift in Drosophila mettleri. While D. mettleri is distributed mainly throughout the Sonoran Desert where it specializes on columnar cacti (Carnegiea gigantea and Pachycereus pringleii), a population on Santa Catalina Island has shifted to chemically divergent coastal prickly pear cactus (Opuntia littoralis). We compared gene expression of larvae from the Sonoran Desert and Santa Catalina Island when reared on saguaro (C. gigantea), coastal prickly pear and laboratory food. Consistent with expectations based on the complexity and toxicity of cactus relative to laboratory food, within-population comparisons between larvae reared on these food sources revealed transcriptional differences in detoxification and other metabolic pathways. The majority of transcriptional differences between populations on the cactus hosts were independent of the rearing environment and included a disproportionate number of genes involved in processes relevant to host plant adaptation (e.g. detoxification, central metabolism and chemosensory pathways). Comparisons of transcriptional reaction norms between the two populations revealed extensive shared plasticity that likely allowed colonization of coastal prickly pear on Santa Catalina Island. We also found that while plasticity may have facilitated subsequent adaptive divergence in gene expression between populations, the majority of genes that differed in expression on the novel host were not transcriptionally plastic in the presumed ancestral state.

  2. Use of cactus in mortars and concrete

    SciTech Connect

    Chandra, S.; Eklund, L.; Villarreal, R.R.

    1998-01-01

    Natural polymers have been used in ancient times to improve the durability of lime-based mortars and concretes. The natural polymers used were locally available. In this work, cactus extract from Mexico has been tested in a Portland cement mortar. It is seen that cactus extract increases the plasticity of the mortar and improves water absorption and freeze-salt resistance. Calcium hydroxide produced by Portland cement hydration interacts with the components of cactus extract, polysaccharides or proteins, and forms complexes. It affects the crystallization process. Painting of the concrete with this extract has also shown improved water resistance.

  3. Mineral resources of Cactus Plain and East Cactus Plain Wilderness Study Areas, La Paz County, Arizona

    SciTech Connect

    Tosdal, R.M.; Eppinger, R.G.; Erdman, J.A.; Hanna, W.F.; Pitkin, J.A.; Blank, H.R. Jr.; O'Leary, R.M.; Watterson, J.R. ); Kreidler, T.J. )

    1990-01-01

    This paper reports on geologic, geochemical, and geophysical studies in the Cactus Plain and East Cactus Plain Wilderness Study Areas outlined in areas with moderate to high potential for gold, silver, copper, lead, zinc, barite, fluorite, manganese, and sand suitable for foundry, fracturing, and abrasive uses and low resource potential for beryllium, uranium and bentonitic clays.

  4. CACTUS.

    ERIC Educational Resources Information Center

    Hyde, Hartley

    1992-01-01

    Utilizes LOGO to teach the concept of inequalities by programing the turtle to take random walks in the coordinate plane restricted to predetermined regions defined by inequalities. The students task is to discover the inequalities that define the illegal areas into which the turtle must not move. Provides examples and corresponding computer…

  5. Cactus

    ERIC Educational Resources Information Center

    Hyde, Hartley

    2007-01-01

    The transfer of data from one part of a computer to another has always been a complex task in which speed is traded against accuracy and the time required for error correction. Much more complex therefore is the transfer of information from one machine to another of a different type. Difficulties arise when machines are updated, when file formats…

  6. Specialization clines in the pollination systems of agaves (Agavaceae) and columnar cacti (Cactaceae): A phylogenetically controlled meta-analysis.

    PubMed

    Munguía-Rosas, Miguel A; Sosa, Vinicio J; Ojeda, Mario M; De-Nova, J Arturo

    2009-10-01

    The biogeography of plant-animal interactions is a novel topic on which many disciplines converge (e.g., reproductive biology, biogeography, and evolutionary biology). Narrative reviews have indicated that tropical columnar cacti and agaves have highly specialized pollination systems, while extratropical species have generalized systems. However, this dichotomy has never been quantitatively tested. We tested this hypothesis using traditional and phylogenetically informed meta-analysis. Three effect sizes were estimated from the literature: diurnal, nocturnal, and hand cross-pollination (an indicator of pollen limitation). Columnar cactus pollination systems ranged from purely bat-pollinated in the tropics to generalized pollination, with diurnal visitors as effective as nocturnal visitors in extratropical regions; even when phylogenetic relatedness among species is taken into account. Metaregressions identified a latitudinal increase in pollen limitation in columnar cacti, but this increase was not significant after correcting for phylogeny. The currently available data for agaves do not support any latitudinal trend. Nectar production of columnar cacti varied with latitude. Although this variation is positively correlated with pollination by diurnal visitors, it is influenced by phylogeny. The degree of specificity in the pollination systems of columnar cacti is heavily influenced by ecological factors and has a predictable geographic pattern.

  7. 75 FR 41073 - South American Cactus Moth Regulations; Quarantined Areas

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-15

    ... Inspection Service 7 CFR Part 301 South American Cactus Moth Regulations; Quarantined Areas AGENCY: Animal... are amending the South American cactus moth regulations by adding the State of Louisiana to the list of areas quarantined because of South American cactus moth. As a result of this action,...

  8. Laboratory experiments on columnar jointing

    NASA Astrophysics Data System (ADS)

    Goehring, L.; Morris, S. W.

    2003-12-01

    The mechanism causing columnar jointing has remained an enticing mystery since the basalt columns of the Giant's Causeway in N. Ireland were first reported to science in the 17th century. This phenomenon, in which shrinkage cracks form a quasi-hexagonal arrangement, has been shown to produce columns in starch, glass, coal, sandstone, and ice, as well as in a variety of lava flows. This suggests that this pattern-forming process is very general in nature. However, most studies of columnar jointing have been confined to field studies of basalt flows. Following Muller, we have experimented with desiccating corn starch in an effort to understand this pattern from a more general point of view. The diffusion and evaporation of water in starch is thought to be analogous to the diffusion and extraction of heat from a basalt flow. By combining direct sampling and x-ray tomography, fully 3D descriptions of columnar jointing were obtained with starch samples. We have characterized the pattern with several statistical indices, which describe its structure and relative disorder. These methods can resolve the ordering of the colonnade near the free surface. We identified two distinct mechanisms by which the mean column area increases during pattern evolution. We found both a slow, almost power-law increase in column area, as well as episodes of sudden catastrophic jumps in scale. The latter suggests that the column scale is not a simple single-valued function of drying rate, but rather a metastable state subject to hysteresis. Such metastable behaviour might explain a fundamental question about columnar jointing -- why the columns are so regular in the direction of their growth. Moreover, these experiments may help discriminate between the various theoretical models of this pattern forming process. Finally, our results lead to predictions that could be tested by field measurements on basaltic colonnades.

  9. Disseminated mite infection with ocular involvement in a juvenile bald eagle (Haliaeetus leucocephalus).

    PubMed

    Bueno-Padilla, Irene; Klauss, Gia; Gardiner, Chris H; Wuenschmann, Arno

    2012-07-01

    A bald eagle (Haliaeetus leucocephalus) was found unable to fly and was admitted to The Raptor Center (TRC). Major clinical signs were thin body condition and a cardiac arrhythmia. Ten days after admission to TRC, ophthalmic examination revealed multiple, distinct serpiginous lesions of chorioretinal atrophy in the ocular fundus of the right eye (OD). The bird was euthanized because of clinical deterioration and poor prognosis. Mites of an undetermined species were found histologically in the retina, episcleral tissues, lungs, and liver at the postmortem examination. Disseminated mite infection should be considered in the differential diagnosis of serpiginous chorioretinal lesions in bald eagles (H. leucocephalus).

  10. Disseminated mite infection with ocular involvement in a juvenile bald eagle (Haliaeetus leucocephalus).

    PubMed

    Bueno-Padilla, Irene; Klauss, Gia; Gardiner, Chris H; Wuenschmann, Arno

    2012-07-01

    A bald eagle (Haliaeetus leucocephalus) was found unable to fly and was admitted to The Raptor Center (TRC). Major clinical signs were thin body condition and a cardiac arrhythmia. Ten days after admission to TRC, ophthalmic examination revealed multiple, distinct serpiginous lesions of chorioretinal atrophy in the ocular fundus of the right eye (OD). The bird was euthanized because of clinical deterioration and poor prognosis. Mites of an undetermined species were found histologically in the retina, episcleral tissues, lungs, and liver at the postmortem examination. Disseminated mite infection should be considered in the differential diagnosis of serpiginous chorioretinal lesions in bald eagles (H. leucocephalus). PMID:22151197

  11. The discovery of columnar jointing on Mars

    USGS Publications Warehouse

    Milazzo, M.P.; Keszthelyi, L.P.; Jaeger, W.L.; Rosiek, M.; Mattson, S.; Verba, C.; Beyer, R.A.; Geissler, P.E.; McEwen, A.S.; ,

    2009-01-01

    We report on the discovery of columnar jointing in Marte Valles, Mars. These columnar lavas were discovered in the wall of a pristine, 16-km-diameter impact crater and exhibit the features of terrestrial columnar basalts. There are discontinuous outcrops along the entire crater wall, suggesting that the columnar rocks covered a surface area of at least 200 km2, assuming that the rocks obliterated by the impact event were similarly jointed. We also see columns in the walls of other fresh craters in the nearby volcanic plains of Elysium Planitia–Amazonis Planitia, which include Marte Vallis, and in a well-preserved crater in northeast Hellas.

  12. Kranc: Cactus modules from Mathematica equations

    NASA Astrophysics Data System (ADS)

    Husa, Sascha; Hinder, Ian; Lechner, Christiane; Schnetter, Erik; Wardell, Barry

    2016-09-01

    Kranc turns a tensorial description of a time dependent partial differential equation into a module for the Cactus Computational Toolkit (ascl:1102.013). This Mathematica application takes a simple continuum description of a problem and generates highly efficient and portable code, and can be used both for rapid prototyping of evolution systems and for high performance supercomputing.

  13. Differences in tolerance to host cactus alkaloids in Drosophila koepferae and D. buzzatii.

    PubMed

    Soto, Ignacio M; Carreira, Valeria P; Corio, Cristian; Padró, Julián; Soto, Eduardo M; Hasson, Esteban

    2014-01-01

    The evolution of cactophily in the genus Drosophila was a major ecological transition involving over a hundred species in the Americas that acquired the capacity to cope with a variety of toxic metabolites evolved as feeding deterrents in Cactaceae. D. buzzatii and D. koepferae are sibling cactophilic species in the D. repleta group. The former is mainly associated with the relatively toxic-free habitat offered by prickly pears (Opuntia sulphurea) and the latter has evolved the ability to use columnar cacti of the genera Trichocereus and Cereus that contain an array of alkaloid secondary compounds. We assessed the effects of cactus alkaloids on fitness-related traits and evaluated the ability of D. buzzatii and D. koepferae to exploit an artificial novel toxic host. Larvae of both species were raised in laboratory culture media to which we added increasing doses of an alkaloid fraction extracted from the columnar cactus T. terschekii. In addition, we evaluated performance on an artificial novel host by rearing larvae in a seminatural medium that combined the nutritional quality of O. sulphurea plus amounts of alkaloids found in fresh T. terschekii. Performance scores in each rearing treatment were calculated using an index that took into account viability, developmental time, and adult body size. Only D. buzzatii suffered the effects of increasing doses of alkaloids and the artificial host impaired viability in D. koepferae, but did not affect performance in D. buzzatii. These results provide the first direct evidence that alkaloids are key determinants of host plant use in these species. However, the results regarding the artificial novel host suggest that the effects of alkaloids on performance are not straightforward as D. koepferae was heavily affected. We discuss these results in the light of patterns of host plan evolution in the Drosophila repleta group.

  14. Differences in Tolerance to Host Cactus Alkaloids in Drosophila koepferae and D. buzzatii

    PubMed Central

    Soto, Ignacio M.; Carreira, Valeria P.; Corio, Cristian; Padró, Julián; Soto, Eduardo M.; Hasson, Esteban

    2014-01-01

    The evolution of cactophily in the genus Drosophila was a major ecological transition involving over a hundred species in the Americas that acquired the capacity to cope with a variety of toxic metabolites evolved as feeding deterrents in Cactaceae. D. buzzatii and D. koepferae are sibling cactophilic species in the D. repleta group. The former is mainly associated with the relatively toxic-free habitat offered by prickly pears (Opuntia sulphurea) and the latter has evolved the ability to use columnar cacti of the genera Trichocereus and Cereus that contain an array of alkaloid secondary compounds. We assessed the effects of cactus alkaloids on fitness-related traits and evaluated the ability of D. buzzatii and D. koepferae to exploit an artificial novel toxic host. Larvae of both species were raised in laboratory culture media to which we added increasing doses of an alkaloid fraction extracted from the columnar cactus T. terschekii. In addition, we evaluated performance on an artificial novel host by rearing larvae in a seminatural medium that combined the nutritional quality of O. sulphurea plus amounts of alkaloids found in fresh T. terschekii. Performance scores in each rearing treatment were calculated using an index that took into account viability, developmental time, and adult body size. Only D. buzzatii suffered the effects of increasing doses of alkaloids and the artificial host impaired viability in D. koepferae, but did not affect performance in D. buzzatii. These results provide the first direct evidence that alkaloids are key determinants of host plant use in these species. However, the results regarding the artificial novel host suggest that the effects of alkaloids on performance are not straightforward as D. koepferae was heavily affected. We discuss these results in the light of patterns of host plan evolution in the Drosophila repleta group. PMID:24520377

  15. Flavobacterium columnare chemotaxis to channel catfish mucus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is a Gram-negative pathogen of many species of wild and cultured fish, especially channel catfish (Ictalurus punctatus). This motile microbe is responsible for severe economic losses to the catfish industry. Flavobacterium columnare isolates from diseased channel catfish b...

  16. Phylogenetic origins of Lophocereus (Cactaceae) and the senita cactus-senita moth pollination mutualism.

    PubMed

    Hartmann, Stefanie; Nason, John D; Bhattacharya, Debashish

    2002-07-01

    Recent ecological research has revealed that the Sonoran Desert columnar cactus Lophocereus and the pyralid moth Upiga virescens form an obligate pollination mutualism, a rare but important case of coevolution. To investigate the phylogenetic origins of this unusual pollination system, we used molecular sequence data to reconstruct the phylogeny of the four taxa within the genus Lophocereus and to determine the phylogenetic position of Lophocereus within the North American columnar cacti (tribe Pachycereeae). Our analysis included Lophocereus, six Pachycereus species, Carnegiea gigantea, and Neobuxbaumia tetetzo within the subtribe Pachycereinae, and Stenocereus thurberi as an outgroup within the Stenocereinae. Extensive screening of chloroplast and mitochondrial genomes failed to reveal sequence variation within Lophocereus. At a deeper phylogenetic level, however, we found strong support for the placement of Lophocereus within Pachycereus as sister group to the hummingbird-pollinated P. marginatus. We discuss possible hypotheses that may explain the transition from bat pollination (ancestral) to moth and hummingbird pollination in Lophocereus and P. marginatus, respectively. Additional phylogenetic analyses suggest that the genus Pachycereus should be expanded to include Lophocereus, Carnegiea, Neobuxbaumia, and perhaps other species, whereas P. hollianus may need to be excluded from this clade. Future study will be needed to test taxonomic distinctions within Lophocereus, to test for parallel cladogenesis between phylogroups within Lophocereus and Upiga, and to fully delineate the genus Pachycereus and relationships among genera in the Pachycereinae.

  17. Habitat Suitability Index Models: Cactus Wren

    USGS Publications Warehouse

    Short, Henry L.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the cactus wren (Campylorhynchus brunneicapillus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  18. Habitat Suitability Index Models: Cactus wren

    USGS Publications Warehouse

    Short, Henry L.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the cactus wren (Campylorhynchus brunneicapillus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  19. Betacyanins from vine cactus Hylocereus polyrhizus.

    PubMed

    Wybraniec, S; Platzner, I; Geresh, S; Gottlieb, H E; Haimberg, M; Mogilnitzki, M; Mizrahi, Y

    2001-12-01

    The presence of betacyanin pigments and their isoforms has been detected in the fruit of Hylocereus polyrhizus, a vine cactus native to South America. Along with the known betanin and phyllocactin (6'-O-malonylbetanin), a new betacyanin was structurally elucidated as betanidin 5-O-[6'-O-(3"-hydroxy-3"-methyl-glutaryl)-beta-D-glucopyranoside] (proposed trivial name hylocerenin) by means of electrospray MS/MS, HPLC, and NMR techniques.

  20. Past climate changes and ecophysiological responses recorded in the isotope ratios of saguaro cactus spines.

    PubMed

    English, Nathan B; Dettman, David L; Sandquist, Darren R; Williams, David G

    2007-11-01

    The stable isotope composition of spines produced serially from the apex of columnar cacti has the potential to be used as a record of changes in climate and physiology. To investigate this potential, we measured the delta(18)O, delta(13)C and F(14)C values of spines from a long-lived columnar cactus, saguaro (Carnegiea gigantea). To determine plant age, we collected spines at 11 different heights along one rib from the stem apex (3.77 m height) to the base of a naturally occurring saguaro. Fractions of modern carbon (F(14)C) ranged from 0.9679 to 1.5537, which is consistent with ages between 1950 and 2004. We observed a very strong positive correlation (r = 0.997) between the F(14)C age of spines and the age of spines determined from direct and repeated height measurements taken on this individual over the past 37 years. A series of 96 spines collected from this individual had delta(18)O values ranging from 38 per thousand to 50 per thousand [Vienna standard mean ocean water (VSMOW)] and delta(13)C values from -11.5 per thousand to -8.5 per thousand [Vienna Peedee belemnite (VPDB)]. The delta(18)O and delta(13)C values of spines were positively correlated (r = 0.45, P < 0.0001) and showed near-annual oscillations over the approximately 15-year record. This pattern suggests that seasonal periods of reduced evaporative demand or greater precipitation input may correspond to increased daytime CO(2) uptake. The lowest delta(18)O and delta(13)C values of spines observed occurred during the 1983 and 1993 El Niño years, suggesting that the stable isotope composition recorded in spine tissue may serve as a proxy for these climate events. We compared empirical models and data from potted experimental cacti to validate these observations and test our hypotheses. The isotopic records presented here are the first ever reported from a chronosequence of cactus spines and demonstrate that tissues of columnar cacti, and potentially other long-lived succulents, may contain a

  1. Past climate changes and ecophysiological responses recorded in the isotope ratios of saguaro cactus spines.

    PubMed

    English, Nathan B; Dettman, David L; Sandquist, Darren R; Williams, David G

    2007-11-01

    The stable isotope composition of spines produced serially from the apex of columnar cacti has the potential to be used as a record of changes in climate and physiology. To investigate this potential, we measured the delta(18)O, delta(13)C and F(14)C values of spines from a long-lived columnar cactus, saguaro (Carnegiea gigantea). To determine plant age, we collected spines at 11 different heights along one rib from the stem apex (3.77 m height) to the base of a naturally occurring saguaro. Fractions of modern carbon (F(14)C) ranged from 0.9679 to 1.5537, which is consistent with ages between 1950 and 2004. We observed a very strong positive correlation (r = 0.997) between the F(14)C age of spines and the age of spines determined from direct and repeated height measurements taken on this individual over the past 37 years. A series of 96 spines collected from this individual had delta(18)O values ranging from 38 per thousand to 50 per thousand [Vienna standard mean ocean water (VSMOW)] and delta(13)C values from -11.5 per thousand to -8.5 per thousand [Vienna Peedee belemnite (VPDB)]. The delta(18)O and delta(13)C values of spines were positively correlated (r = 0.45, P < 0.0001) and showed near-annual oscillations over the approximately 15-year record. This pattern suggests that seasonal periods of reduced evaporative demand or greater precipitation input may correspond to increased daytime CO(2) uptake. The lowest delta(18)O and delta(13)C values of spines observed occurred during the 1983 and 1993 El Niño years, suggesting that the stable isotope composition recorded in spine tissue may serve as a proxy for these climate events. We compared empirical models and data from potted experimental cacti to validate these observations and test our hypotheses. The isotopic records presented here are the first ever reported from a chronosequence of cactus spines and demonstrate that tissues of columnar cacti, and potentially other long-lived succulents, may contain a

  2. POPULATION DYNAMICS OF THE CACTUS MOTH, CACTOBLASTIS CACTORUM IN FLORIDA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field populations of the cactus moth, Cactoblastis cactorum were surveyed weekly beginning in July 2006. We sampled the native cactus, Opuntia stricta visually to determine the densities and development of immature stages. Adult males were collected using a synthetic pheromone and a sticky wing trap...

  3. Ecology and control of an invasive pest, the cactus moth, Cactoblastis cactorum (Lepidoptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cactus moth, Cactoblastis cactorum, was one of the success stories in classical biological control. In the 1920s, the prickly pear cactus was a serious pest in Australia. The cactus moth was imported from its native habitat in South America and proved so successful in controlling cactus that it ...

  4. Discovery of columnar jointing on Mars

    USGS Publications Warehouse

    Milazzo, M.P.; Keszthelyi, L.P.; Jaeger, W.L.; Rosiek, M.; Mattson, S.; Verba, C.; Beyer, R.A.; Geissler, P.E.; McEwen, A.S.

    2009-01-01

    We report on the discovery of columnar jointing in Marte Valles, Mars. These columnar lavas were discovered in the wall of a pristine, 16-km-diameter impact crater and exhibit the features of terrestrial columnar basalts. There are discontinuous outcrops along the entire crater wall, suggesting that the columnar rocks covered a surface area of at least 200 km2, assuming that the rocks obliterated by the impact event were similarly jointed. We also see columns in the walls of other fresh craters in the nearby volcanic plains of Elysium Planitia-Amazonis Planitia, which include Marte Vallis, and in a well-preserved crater in northeast Hellas. ?? 2009 The Geological Society of America.

  5. Low DDT residues in plasma of bald eagles (Haliaeetus leucocephalus) wintering in Colorado and Missouri

    USGS Publications Warehouse

    Henny, C.J.; Griffin, C.R.; Stahlecker, D.W.; Harmata, A.R.; Cromartie, E.

    1981-01-01

    Residues of DDT and its metabolites (Z:DDT) in blood plasma from Bald Eagles (Haliaeetus leucocephalus) wintering in Colorado and Missouri were low (0.06-0.14 ?g/g) in 1977 and 1978. Most of the adult wintering birds probably nest in Canada, although a few in Missouri may be from Minnesota or the Great Lakes region. DDE residues in eggs, estimated from those in plasma, were lower than those reported from Saskatchewan in 1969-1972 (4.5 ?g/g vs. 0.67 ?g//g); this suggests reduced environmental contamination.

  6. A 26-year Composite Stable Isotope Record of Precipitation, Humidity and El Niño in the Spines of Saguaro Cactus, Carnegiea gigantea.

    NASA Astrophysics Data System (ADS)

    English, N. B.; Dettman, D. L.; Williams, D. G.

    2008-12-01

    Seasonal cycles of rainfall and humidity are recorded by stable isotopes in the spines of columnar cactuses. Multi-decadal δ18O and δ13C records of spine series from five saguaro cactuses, dated using bomb radiocarbon and semi-annual variations in δ13C, demonstrate the reproducibility of a climate signal. For δ18O and δ13C, the expressed population signal between 1980 and 2006 is 0.68 and 0.66, respectively, but 0.76 and 0.59 between 1980 and 1997, suggesting that age/height related effects are present in isotopic spine series. Composite δ18O and δ13C records constructed from five spine series show significant relationships to external climate forcing. Once dating errors are corrected, mean annual spine δ18O is negatively correlated with total annual precipitation (TAP) from November through October (P < 0.001) and positively correlated with mean annual nighttime vapor pressure deficit (VPD) (P < 0.01). Year to year decreases (> 2‰) in the maximum annual spine δ18O are positively correlated with the Southern Oscillation Index (P < 0.01). We hypothesize these decreases are caused by El Niño enhanced winter rainfall. While less significant, minimum annual δ13C is negatively correlated with TAP (P < 0.05) and mean nighttime VPD (P < 0.05). These results bolster proposed mechanistic models of isotopic variation in the spines of columnar cactuses and demonstrate the use of isotopic spine series as climate proxies.

  7. DISPERSAL OF SEEDS AS NEST MATERIAL BY THE CACTUS WREN

    EPA Science Inventory

    Cactus wren (Campylorhynchus brunneicapillus) nests from the southern Chihuahuan Desert contained viable seeds of grasses, forbs, and shrubs. The most common plants used as construction material in these nests were Muhlenbergia porteri, Boerhavia spicata, and the alien grass Era...

  8. Genome sequence of the fish pathogen Flavobacterium columnare ATCC 49512

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is a Gram-negative, rod shaped, motile, and highly prevalent fish pathogen causing columnaris disease in freshwater fish worldwide. Here, we present the complete genome sequence of F. columnare strain ATCC 49512. ...

  9. Population transcriptomics of cactus host shifts in Drosophila mojavensis.

    PubMed

    Matzkin, Luciano M

    2012-05-01

    In the presence of environmental change, natural selection can shape the transcriptome. Under a scenario of environmental change, genotypes that are better able to modulate gene expression to maximize fitness will tend to be favoured. Therefore, it is important to examine gene expression at the population level to distinguish random or neutral gene expression variation from the pattern produced by natural selection. This study investigates the natural variation in transcriptional response to a cactus host shift utilizing the mainland Sonora population of Drosophila mojavensis. Drosophila mojavensis is a cactophilic species composed of four cactus host populations endemic to the deserts of North America. Overall, the change in cactus host was associated with a significant reduction in larval viability as well as the differential expression of 21% of the genome (3109 genes). Among the genes identified were a set of genes previously known to be involved in xenobiotic metabolism, as well as genes involved in cellular energy production, oxidoreductase/carbohydrate metabolism, structural components and mRNA binding. Interestingly, of the 3109 genes whose expression was affected by host use, there was a significant overrepresentation of genes that lacked an orthologous call to the D. melanogaster genome, suggesting the possibility of an accelerated rate of evolution in these genes. Of the genes with a significant cactus effect, the majority, 2264 genes, did not exhibit a significant cactus-by-line interaction. This population-level approach facilitated the identification of genes involved in past cactus host shifts.

  10. Uniaxial alignment of nanoconfined columnar mesophases.

    PubMed

    Mouthuy, Pierre-Olivier; Melinte, Sorin; Geerts, Yves H; Jonas, Alain M

    2007-09-01

    By confining discotic phthalocyanines in a network of crisscrossed nanogrooves, we obtain a uniaxial alignment of the columnar mesophase. The alignment process is based on the anisotropy of interface tension between the mesophase and the nanogrooves' walls. Preferential mesophase alignment results from this nonhomogeneity combined with the anisotropy of the network cell dimensions. A simple model is proposed to explain the experimental observations.

  11. Parasitism enhances tilapia susceptibility to Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare, a Gram-negative bacterium, is the causative agent of columnaris disease. Many commercially important freshwater fish worldwide are susceptible to columnaris disease that can result in high fish mortality. Ichthyophthirius multifiliis (Ich) is a protozoan parasite in many ...

  12. Annealing a magnetic cactus into phyllotaxis

    NASA Astrophysics Data System (ADS)

    Nisoli, Cristiano; Gabor, Nathaniel M.; Lammert, Paul E.; Maynard, J. D.; Crespi, Vincent H.

    2010-04-01

    The appearance of mathematical regularities in the disposition of leaves on a stem, scales on a pine-cone, and spines on a cactus has puzzled scholars for millennia; similar so-called phyllotactic patterns are seen in self-organized growth, polypeptides, convection, magnetic flux lattices and ion beams. Levitov showed that a cylindrical lattice of repulsive particles can reproduce phyllotaxis under the (unproved) assumption that minimum of energy would be achieved by two-dimensional Bravais lattices. Here we provide experimental and numerical evidence that the Phyllotactic lattice is actually a ground state. When mechanically annealed, our experimental “magnetic cactus” precisely reproduces botanical phyllotaxis, along with domain boundaries (called transitions in Botany) between different phyllotactic patterns. We employ a structural genetic algorithm to explore the more general axially unconstrained case, which reveals multijugate (multiple spirals) as well as monojugate (single-spiral) phyllotaxis.

  13. Comparative cactus architecture and par interception

    SciTech Connect

    Geller, G.N.; Nobel, P.S. )

    1987-07-01

    Because CO{sup 2} uptake by cacti can be limited by low levels of photosynthetically active radiation (PAR) and because plant form affects PAR interception, various cactus forms were studied using a computer model, field measurements, and laboratory phototropic studies. Model predictions indicated that CO{sub 2} uptake by individual stems at an equinox was greatest when the stem were vertical, but at the summer and the winter solstice CO{sub 2} uptake was greatest for stems titled 30{degree} away from the equator. Stem tilting depended on form and taxonomic group. Not only can the shape of cacti be affected by PAR, but also shape influences PAR interception and hence CO{sub 2} uptake.

  14. Stem biomechanics of three columnar cacti from the Sonoran Desert.

    PubMed

    Molina-Freaner, F; Tinoco-Ojanguren, C; Niklas, K

    1998-08-01

    The allometric relationship of stem length L with respect to mean stem diameter D was determined for 80 shoots of each of three columnar cactus species (Stenocereus thurberi, Lophocereus schottii, and S. gummosus) to determine whether this relationship accords with that predicted by each of three contending models purporting to describe the mechanical architecture of vertical shoots (i.e., geometric, stress, and elastic similitude, which predict L proportional to D(alpha), with alpha = 1/1, 1/2, and 2/3, respectively). In addition, anatomical, physical, and biomechanical stem properties were measured to determine how the stems of these three species maintain their elastic stability as they increase in size. Reduced major axis regression of L with respect to D showed that alpha = 2.82 ± 0.14 for S. thurberi, 2.32 ± 0.19 for L. schottii, and 4.21 ± 0.31 for S. gummosus. Thus, the scaling exponents for the allometry of L differed significantly from that predicted by each of the three biomechanical models. In contrast, these exponents were similar to that for the allometry previously reported for saguaro. Analyses of biomechanical data derived from bending tests performed on 30 stems selected from each of the three species indicated that the bulk stem tissue stiffness was roughly proportional to L2, while stem flexural rigidity (i.e., the ability to resist a bending force) scaled roughly as L3. Stem length was significantly and positively correlated with the volume fraction of wood, while regression analysis of the pooled data from the three species (i.e., 90 stems) indicated that bulk tissue stiffness scaled roughly as the 5/3-power of the volume fraction of wood in stems. These data were interpreted to indicate that wood served as the major stiffening agent in stems and that this tissue accumulates at a sufficient rate to afford unusually high scaling exponents tot stem length with respect to stem diameter (i.e., disproportionately large increments of stem length

  15. Reproduction, longevity and survival of the cactus moth, Cactoblastis cactorum (Lepidoptera: Pyralidae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Screened potted cactus plants (Opuntia ficus-indica (L.) Mill.) containing pairs of adult male and female cactus moths, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), were placed in a cactus field in St. Marks, Florida to measure oviposition patterns under field-realistic conditions. Results...

  16. Tibiotarsal fracture repair in a bald eagle (Haliaeetus leucocephalus) using an interlocking nail.

    PubMed

    Hollamby, Simon; Dejardin, Loic M; Sikarskie, James G; Haeger, Jennifer

    2004-03-01

    A 14-yr-old, 5.13-kg bald eagle (Haliaeetus leucocephalus) was hit by a car and presented to the Michigan State University Small Animal Clinic with an open, grade II, transverse, midshaft, Winquist-Hansen type-II-comminuted left tibiotarsal fracture. The fracture was reduced and fixation established with a 4.7-mm-diameter, 112-mm-long, four-hole veterinary intramedullary interlocking nail maintained in position by single 2-mm transcortical screws placed in the main proximal and distal fragments. The bird was weight bearing on the bandaged limb 48 hr postoperatively. Radiographs obtained 4 wk postoperatively revealed bridging callus over three of four cortices. The bird was released after 5 mo of rehabilitation.

  17. Sarcocystis sp.-associated meningoencephalitis in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Olson, Erik J; Wünschmann, Arno; Dubey, J P

    2007-09-01

    Protozoal meningoencephalitis is uncommon in raptors. An adult female bald eagle (Haliaeetus leucocephalus) was euthanized after several months of treatment for progressive neurologic signs. The predominant histologic lesion was lymphoplasmacytic and histiocytic meningoencephalitis involving the cerebrum and cerebellum. There was a marked segmental loss of granular cells and Purkinje cells, as well as segmental atrophy of the molecular layer in the cerebellum. Protozoal merozoites and schizonts were observed in the gray matter of the cerebellum. Ultrastructurally, the merozoites were classified as a species of Sarcocystis due to the lack of rhoptries. Immunohistochemistry of the agent revealed a positive reaction for Sarcocystis neurona, while sections were negative for Toxoplasma gondii and Neospora caninum. Sarcocystis sp. infection should be considered as a differential diagnosis in bald eagles with chronic neurologic disease.

  18. Detection and characterization of a Trichomonas isolate from a rehabilitated bald eagle (Haliaeetus leucocephalus).

    PubMed

    Kelly-Clark, Whitney K; McBurney, Scott; Forzán, María J; Desmarchelier, Marion; Greenwood, Spencer J

    2013-12-01

    A hatching-year bald eagle (Haliaeetus leucocephalus) was presented for clinical examination after being found unable to fly. Upon admission, routine wet-mount microscopy detected no trichomonads. Five months later, oral cavity inspection found no abnormalities, but the eagle was swabbed for research on trichomonosis in maritime birds. The swab was used to inoculate an InPouch TF culture and trichomonads were visible within 24 hr. Genotyping (ITS) revealed a Trichomonas isolate that was 100% identical to an isolate from a bearded vulture (Gypaetus barbatus) from the Czech Republic. The eagle was treated with metronidazole (50 mg/kg q 12h PO for 5 consecutive days). Following treatment, the eagle was swabbed and the inoculated InPouch TF culture was monitored daily for 1 wk. No trichomonads were observed. Rehabilitation centers interested in surveillance should consider combining the InPouch TF technique with clinical inspection of live birds to confirm trichomonosis and for future research.

  19. Detection and characterization of a Trichomonas isolate from a rehabilitated bald eagle (Haliaeetus leucocephalus).

    PubMed

    Kelly-Clark, Whitney K; McBurney, Scott; Forzán, María J; Desmarchelier, Marion; Greenwood, Spencer J

    2013-12-01

    A hatching-year bald eagle (Haliaeetus leucocephalus) was presented for clinical examination after being found unable to fly. Upon admission, routine wet-mount microscopy detected no trichomonads. Five months later, oral cavity inspection found no abnormalities, but the eagle was swabbed for research on trichomonosis in maritime birds. The swab was used to inoculate an InPouch TF culture and trichomonads were visible within 24 hr. Genotyping (ITS) revealed a Trichomonas isolate that was 100% identical to an isolate from a bearded vulture (Gypaetus barbatus) from the Czech Republic. The eagle was treated with metronidazole (50 mg/kg q 12h PO for 5 consecutive days). Following treatment, the eagle was swabbed and the inoculated InPouch TF culture was monitored daily for 1 wk. No trichomonads were observed. Rehabilitation centers interested in surveillance should consider combining the InPouch TF technique with clinical inspection of live birds to confirm trichomonosis and for future research. PMID:24450084

  20. Sarcocystis sp.-associated meningoencephalitis in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Olson, Erik J; Wünschmann, Arno; Dubey, J P

    2007-09-01

    Protozoal meningoencephalitis is uncommon in raptors. An adult female bald eagle (Haliaeetus leucocephalus) was euthanized after several months of treatment for progressive neurologic signs. The predominant histologic lesion was lymphoplasmacytic and histiocytic meningoencephalitis involving the cerebrum and cerebellum. There was a marked segmental loss of granular cells and Purkinje cells, as well as segmental atrophy of the molecular layer in the cerebellum. Protozoal merozoites and schizonts were observed in the gray matter of the cerebellum. Ultrastructurally, the merozoites were classified as a species of Sarcocystis due to the lack of rhoptries. Immunohistochemistry of the agent revealed a positive reaction for Sarcocystis neurona, while sections were negative for Toxoplasma gondii and Neospora caninum. Sarcocystis sp. infection should be considered as a differential diagnosis in bald eagles with chronic neurologic disease. PMID:17823405

  1. Bacterial succession in necrotic tissue of agria cactus (Stenocereus gummosus).

    PubMed Central

    Foster, J L; Fogleman, J C

    1994-01-01

    The bacterial communities associated with the development of necroses in injured agria cactus tissue were examined in the field by using both human-induced injuries and cactus tissue inoculated with cactophilic bacteria. Whole-cell bacterial fatty acids were used to determine when and where each of 23 detected species occurred. This information was then used to describe successional patterns of bacterial colonization. Although the number of bacterial species in human-induced injuries reached a maximum on day 16, the Shannon-Weaver diversity index increased to a plateau, which reflects a stable bacterial community. The potential of the bacterial community to macerate the injured cactus tissue was also examined, and the results indicate that the bacteria initially colonizing the newly injured cactus tissue were more likely to contain pectinolytic, proteolytic, and lipolytic enzymes than were the bacteria entering the injuries once tissue maceration had already begun. The cactophilic fruit fly Drosophila mojavensis has been previously shown to carry bacteria to newly injured cactus tissue. In these studies, exclusion of these insects did not significantly affect bacterial succession or community structure. This supports our contention that bacteria colonize injured tissue primarily by passive transport, e.g., on wind-blown particles. PMID:8135520

  2. Population genetics and phylogenetic relationships of beetles (Coleoptera: Histeridae and Staphylinidae) from the Sonoran Desert associated with rotting columnar cacti.

    PubMed

    Pfeiler, Edward; Johnson, Sarah; Richmond, Maxi Polihronakis; Markow, Therese A

    2013-12-01

    Dozens of arthropod species are known to feed and breed in the necrotic tissues (rots) of columnar cacti in the Sonoran Desert. Because the necrotic patches are ephemeral, the associated arthropods must continually disperse to new cacti and therefore the populations of any given species are expected to show very little local genetic differentiation. While this has been found to be true for the cactophilic Drosophila, the evolutionary histories and characteristics of other arthropods inhabiting the same necrotic patches, especially the beetles, have yet to be examined. Here we used nucleotide sequence data from segments of the mitochondrial 16S rRNA and cytochrome c oxidase subunit I (COI) genes to examine population structure and demographic history of three sympatric beetle species (Coleoptera: Histeridae and Staphylinidae) collected on senita cactus (Lophocereus schottii) from six widely-separated localities on the Baja California peninsula of northwestern Mexico. Two histerids, Iliotona beyeri and Carcinops gilensis, and an unidentified staphylinid, Belonuchus sp., showed little or no population structure over a broad geographic area on the peninsula, consistent with the prediction that these beetles should show high dispersal ability. Demographic tests revealed varying levels of historical population expansion among the beetle species analyzed, which are discussed in light of their ecologies and concurrent biogeographic events. Additionally, phylogenetic analyses of COI sequences in Carcinops collected on a variety of columnar cacti from both peninsular and mainland Mexico localities revealed several species-level partitions, including a putative undescribed peninsular species that occurred sympatrically with C. gilensis on senita.

  3. Pulse seedling recruitment on the population dynamics of a columnar cactus: Effect of an extreme rainfall event

    NASA Astrophysics Data System (ADS)

    Arroyo-Cosultchi, Gabriel; Golubov, Jordan; Mandujano, María C.

    2016-02-01

    Demographic studies on the Cactaceae have highlighted several threats which are clearly human induced (e.g., disturbance) or intrinsic to their biology (e.g., infrequent recruitment). Most demographic studies suggest that early life stages of germination and seedling recruitment are crucial and often a limitation for population growth. The population dynamics of Neobuxbaumia polylopha (DC) Backeb. was modeled for a three-year period to assess the contribution of the early life cycle stages on population growth rate (λ). Two annual size-classified matrix population models were constructed for standard analysis, applied a life table response experiment (LTRE) analysis to explore the contributions of demographic processes, plant size, and temporal variability (years) to λ, and changes in the matrix elements were simulated including a seed bank, and seed-to-seedling transition using observed and experimental data. The population growth rates for 2012-2013 and 2013-2014 were 0.9916 (0.9906-0.9929) and 1.0216 (1.011-1.0280) respectively, suggesting two opposite growth rates for the studied period. The increase in λ in 2013-2014 was driven primarily by the increased growth and seedling recruitment and survival of small individuals. The rate of recruitment was higher in 2013-2014 with a left-skewed stable size distribution. Elasticity values were high for matrix entries corresponding to individuals remaining in the same category (stasis), followed by growth, retrogression and fecundity. The simulations show that the seed bank has a minor effect in comparison with the seed-seedling transition which became the population bottleneck under the assumption that seeds are not limited, so programs designed to preserve N. polylopha populations must focus on seedling establishment.

  4. Measurement of the flow past a cactus-inspired cylinder

    NASA Astrophysics Data System (ADS)

    Oweis, Ghanem F.; El-Makdah, Adnan M.

    2012-11-01

    Desert cacti are tall cylindrical plants characterized by longitudinal u- or v-shaped grooves that run parallel to the plant axis, covering its surface area. We study the wake flow modifications resulting from the introduction of cactus-inspired surface grooves to a circular cylinder. Particle image velocimetry PIV is implemented in a wind tunnel to visualize and quantify the wake flow from a cactus cylinder in cross wind and an equivalent circular cylinder at Re O(1E5). The cactus wake exhibits superior behavior over its circular counterpart as seen from the mean and turbulent velocity profiles. The surface flow within the grooves is also probed to elucidate the origins of the wake alterations. Lastly, we use simple statistical analysis based only on the wake velocity fields, under the assumption of periodicity of the shedding, to recover the time varying flow from the randomly acquired PIV snapshots.

  5. Corrective action investigation plan: Cactus Spring Waste Trenches. Revision 2

    SciTech Connect

    1997-02-01

    This Correction Action Investigation Plan (CAIP) contains environmental sample collection objectives and logic for the CAU No. 426, which includes the Cactus Spring Waste Trenches, CAS No. RG-08-001-RG-CS. The Cactus Spring Waste Trenches are located at the Tonopah Test Range (TTR) which is part of the Nellis Air Force Range, approximately 255 kilometers (km) (140 miles [mi]) northwest of Las Vegas, Nevada, by air. The purpose of this investigation is to generate sufficient data to establish the types of waste buried in the trenches, identify the presence and nature of contamination, determine the vertical extent of contaminant migration below the Cactus Spring Waste Trenches, and determine the appropriate course of action for the site. The potential courses of action for the site are clean closure, closure in place (with or without remediation), or no further action.

  6. Theoretical Exploration of Barrel-Shaped Drops on Cactus Spines.

    PubMed

    Luo, Cheng

    2015-11-01

    To survive an arid environment, desert cacti are capable of harvesting water from fog by transporting condensed water drops using their spines. Cactus spines have a conical shape. In this work, on the basis of the difference of liquid pressure, a new theoretical model has been developed for a barrel-shaped liquid drop on a conical wire. This model is further simplified to interpret the effects of contact angles, conical angle, surface microgrooves, and gravity on the drop movement along a cactus spine.

  7. Theoretical Exploration of Barrel-Shaped Drops on Cactus Spines.

    PubMed

    Luo, Cheng

    2015-11-01

    To survive an arid environment, desert cacti are capable of harvesting water from fog by transporting condensed water drops using their spines. Cactus spines have a conical shape. In this work, on the basis of the difference of liquid pressure, a new theoretical model has been developed for a barrel-shaped liquid drop on a conical wire. This model is further simplified to interpret the effects of contact angles, conical angle, surface microgrooves, and gravity on the drop movement along a cactus spine. PMID:26473466

  8. Response of tender cactus pads to Salmonella strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tender cactus pads (cladodes) or nopalitos (Opuntia ficus-indica L) are an important vegetable in Mexico. They are often pre-trimmed, cut and packaged, and while usually consumed cooked, they may also be eaten raw in salads. Salmonella is an enteropathogenic bacterium that can adapt to adverse envir...

  9. CACTUS: Command and Control Training Using Knowledge-Based Simulations.

    ERIC Educational Resources Information Center

    Hartley, J. R.; And Others

    1992-01-01

    Describes a computer simulation, CACTUS, that was developed in the United Kingdom to help police with command and control training for large crowd control incidents. Use of the simulation for pre-event planning and decision making is discussed, debriefing is described, and the role of the trainer is considered. (LRW)

  10. CACTUS: Command and Control Training Using Knowledge-Based Simulations

    ERIC Educational Resources Information Center

    Hartley, Roger; Ravenscroft, Andrew; Williams, R. J.

    2008-01-01

    The CACTUS project was concerned with command and control training of large incidents where public order may be at risk, such as large demonstrations and marches. The training requirements and objectives of the project are first summarized justifying the use of knowledge-based computer methods to support and extend conventional training…

  11. Repair of a coracoid luxation and a tibiotarsal fracture in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Guzman, David Sanchez-Migallon; Bubenik, Loretta J; Lauer, Susanne K; Vasanjee, Sunil; Mitchell, Mark A

    2007-09-01

    A 4.5-kg, adult bald eagle (Haliaeetus leucocephalus) was presented after being found unable to fly. Crepitus was palpated in the left shoulder; however, the wing position was normal. Radiographs revealed caudoventral luxation of the left coracoid, affecting its distal articulation with the clavicle and its proximal articulation with the sternum. The luxation affecting the coracoid-sternum articulation was repaired by using a 4-hole, 1.5-mm T-plate and a 6-hole, 2.0-mm dynamic compression plate (DCP) placed side by side. The luxation affecting the coracoid and the clavicle was repaired by 2 cerclage wires in a simple interrupted pattern. Before a scheduled release, the bird sustained a closed, complete mid diaphyseal transverse fracture of the right tibiotarsus, which most likely occurred during recapture from the flight cage. The fracture was surgically repaired with 2 circumferential cerclage wires, an intramedullary Kirschner wire and one 10-hole, 2.7-mm DCP. The bird was successfully released, 105 days after the first surgery, near the location where it was found.

  12. Pharmacokinetics of intravenous and oral tramadol in the bald eagle (Haliaeetus leucocephalus).

    PubMed

    Souza, Marcy J; Martin-Jimenez, Tomas; Jones, Michael P; Cox, Sherry K

    2009-12-01

    Analgesia is becoming increasingly important in veterinary medicine, and little research has been performed that examined pain control in avian species. Tramadol is a relatively new drug that provides analgesia by opioid (mu), serotonin, and norepinephrine pathways, with minimal adverse effects. To determine the pharmacokinetics of tramadol and its major metabolite O-desmethyltramadol (M1) in eagles, 6 bald eagles (Haliaeetus leucocephalus) were each dosed with tramadol administered intravenously (4 mg/kg) and orally (11 mg/kg) in a crossover study. Blood was collected at various time points between 0 and 600 minutes and then analyzed with high-performance liquid chromatography to determine levels of tramadol and M1, the predominate active metabolite. The terminal half-life of tramadol after intravenous dosing was 2.46 hours. The maximum plasma concentration, time of maximum plasma concentration, and terminal half life for tramadol after oral dosing were 2156.7 ng/ml, 3.75 hours, and 3.14 hours, respec vely. In addition, the oral bioavailability was 97.9%. Although plasma concentrations of ramadol and M1 associated with analgesia in any avian species is unknown, based on the obtained data and known therapeutic levels in humans, a dosage of 5 mg/kg PO q12h is recommended for bald eagles. Pharmacodynamic studies are needed to better determine plasma levels of tramadol and M1 associated with analgesia in birds.

  13. Fighting behavior in Bald Eagles: a test of game theory. [Haliaeetus leucocephalus

    SciTech Connect

    Hansen, A.J.

    1986-06-01

    Seven predictions of evolutionary game theory were examined in field studies of foraging behavior of Bald Eagles (Haliaeetus leucocephalus) wintering in the Chilkat Valley, Alaska. A cost/benefit analysis revealed that the frequencies of two foraging strategies (hunting and stealing from conspecifics) were balanced such that the payoffs of the two were nearly equal. Asymmetries in probable correlates of fighting ability (size and, possibly, spatial position (being in the air vs. on the ground), but not age) and expected gain in victory (hunger level) influenced the outcome of contests over food. Individuals used conditions strategies: small or young birds appeared to hung (rather than steal) relatively more often than others. Pirating eagles often assessed the size and hunger level of food defenders and attacked those most likely to retreat. Contrary to prediction, ritualized displays served to advertise expected gain in victory and were good indicators of subsequent behavior. The level of escalated fighting was inversely related to resource availability. Finally, a graphical model shows that pirating frequency may or may not be influenced by changes in food abundance. The results generally support the predictions of game theory and explain several aspects of Bald Eagle foraging behavior.

  14. Multiple metals exposure and neurotoxic risk in bald eagles (Haliaeetus leucocephalus) from two Great Lakes states.

    PubMed

    Nam, Dong-Ha; Rutkiewicz, Jennifer; Basu, Niladri

    2012-03-01

    In the present study, the authors determined concentrations of several elements (As, Cd, Co, Cu, Cr, Mn, Pb, Sb, Zn) in the brains and livers of 46 bald eagles (Haliaeetus leucocephalus) from two Great Lakes states, Michigan and Minnesota. To explore whether exposures are of neurological concern, the authors assessed their associations with neurochemical receptors (N-methyl-D-aspartate [NMDA] and γ-aminobutyric acid A [GABA(A)]) and enzymes (glutamine synthetase [GS] and glutamic acid decarboxylase [GAD]) that play critical roles in vertebrate neurobehavior and reproduction. For most elements, levels in the livers and brains did not differ between region and gender. Hepatic Pb levels averaged 33.1 ppm (dry wt), 30.4% of all carcasses exceeded proposed avian Pb thresholds (>26.4 ppm), and in 30.8% of the birds examined evidence of Pb pellets or fragments was found. Significant changes in the activities of GS and GAD were related to brain concentrations of several metals (Pb, Cd, Co, Cu, Zn). No relationships were found among any of the nine elements and NMDA or GABA(A) receptor levels. When combined with the authors' previous study on these same eagles that showed Hg-associated alterations in GS, GAD, and NMDA receptor levels, the present research suggests that bald eagles are exposed to various elements, especially Pb and Hg, that are capable of causing changes in GABAergic and glutamatergic neurotransmission. The functional significance of these neurochemical changes warrants attention.

  15. Behavioral ecology of bald eagles along the northwest coast: a landscape perspective. [Haliaeetus leucocephalus

    SciTech Connect

    Hansen, A.J.; Dyer, M.I.; Shugart, H.H.; Boeker, E.L.

    1986-02-01

    Much of the range of the bald eagle (Haliaeetus leucocephalus) has been subjected to anthropogenic disturbance of greater magnitude than the natural regimes of pre-European settlement times. Consequently, many eagle populations are depauperate. Eagle populations are large and stable, however, along the relatively pristine Pacific Northwest Coast of North America. This study examines: (1) the behavior and ecology of bald eagles along the northwest coast; and (2) the effects of environmental disturbance and resource dynamics on the ecology and evolution of eagles. The ephemeral nature of food supplies along the northwest coast apparently results in eagles being limited primarily by food stress. The foraging behavior of eagles was analyzed using evolutionary game theory as a theoretical construct. Productivity was found to be variable and generally declining in southeast Alaska. Eagles maximized energy input for survival by feeding opportunistically, making broad-scale movements to find food patches, locating food within a patch by searching for prey or for conspecifics with prey, assessing prey profitability, acquiring food by hunting and stealing, and by defending food through threat displays or fighting. Eagles obtain food for reproduction by defending feeding territories and by storing food in their nests. These strategies and adaptations translate up scale and influence characteristics of the regional population. 34 figs., 21 tabs.

  16. Relationship of diets and environmental contaminants in wintering bald eagles. [Haliaeetus leucocephalus

    SciTech Connect

    Frenzel, R.W.; Anthony, R.G. )

    1989-07-01

    We investigated the relationship between diets and potential hazards in contaminants of wintering bald eagles (Haliaeetus leucocephalus) in the Klamath Basin of northern California and southern Oregon. We studied diets by identifying remains of 913 prey items found at perches, examining 341 castings collected from communal night roots, and observing foraging eagles. We determined residues of organochlorine compounds, lead (Pb), and mercury (Hg) in bald eagles and their prey by analyzing eagle blood samples and carcasses and 8 major prey species. Bald eagles fed largely on waterfowl by scavenging cholera-killed ducks and geese and on microtine rodents during mid- to late winter. Residues of organochlorine pesticides and Hg in prey were low, and polychlorinated biphenyls (PCB's) were detected in low concentrations in 9% of prey samples. Means Pb concentrations in prey ranged from 0.15 to 4.79 ppm. Mercury was detected in all eagle blood samples, and Pb was detected in 41% of the bald eagle blood samples. Mean Pb concentration in livers of dead eagles was 2.09 ppm and ranged as high as 27 ppm in an eagle that died of Pb poisoning. Prey of the eagles were relatively free of contaminants with the possible exception of embedded Pb shot in waterfowl, which may present a potential for Pb poisoning of eagles.

  17. Pharmacokinetics of intravenous and oral tramadol in the bald eagle (Haliaeetus leucocephalus).

    PubMed

    Souza, Marcy J; Martin-Jimenez, Tomas; Jones, Michael P; Cox, Sherry K

    2009-12-01

    Analgesia is becoming increasingly important in veterinary medicine, and little research has been performed that examined pain control in avian species. Tramadol is a relatively new drug that provides analgesia by opioid (mu), serotonin, and norepinephrine pathways, with minimal adverse effects. To determine the pharmacokinetics of tramadol and its major metabolite O-desmethyltramadol (M1) in eagles, 6 bald eagles (Haliaeetus leucocephalus) were each dosed with tramadol administered intravenously (4 mg/kg) and orally (11 mg/kg) in a crossover study. Blood was collected at various time points between 0 and 600 minutes and then analyzed with high-performance liquid chromatography to determine levels of tramadol and M1, the predominate active metabolite. The terminal half-life of tramadol after intravenous dosing was 2.46 hours. The maximum plasma concentration, time of maximum plasma concentration, and terminal half life for tramadol after oral dosing were 2156.7 ng/ml, 3.75 hours, and 3.14 hours, respec vely. In addition, the oral bioavailability was 97.9%. Although plasma concentrations of ramadol and M1 associated with analgesia in any avian species is unknown, based on the obtained data and known therapeutic levels in humans, a dosage of 5 mg/kg PO q12h is recommended for bald eagles. Pharmacodynamic studies are needed to better determine plasma levels of tramadol and M1 associated with analgesia in birds. PMID:20235455

  18. Multiple metals exposure and neurotoxic risk in bald eagles (Haliaeetus leucocephalus) from two Great Lakes states.

    PubMed

    Nam, Dong-Ha; Rutkiewicz, Jennifer; Basu, Niladri

    2012-03-01

    In the present study, the authors determined concentrations of several elements (As, Cd, Co, Cu, Cr, Mn, Pb, Sb, Zn) in the brains and livers of 46 bald eagles (Haliaeetus leucocephalus) from two Great Lakes states, Michigan and Minnesota. To explore whether exposures are of neurological concern, the authors assessed their associations with neurochemical receptors (N-methyl-D-aspartate [NMDA] and γ-aminobutyric acid A [GABA(A)]) and enzymes (glutamine synthetase [GS] and glutamic acid decarboxylase [GAD]) that play critical roles in vertebrate neurobehavior and reproduction. For most elements, levels in the livers and brains did not differ between region and gender. Hepatic Pb levels averaged 33.1 ppm (dry wt), 30.4% of all carcasses exceeded proposed avian Pb thresholds (>26.4 ppm), and in 30.8% of the birds examined evidence of Pb pellets or fragments was found. Significant changes in the activities of GS and GAD were related to brain concentrations of several metals (Pb, Cd, Co, Cu, Zn). No relationships were found among any of the nine elements and NMDA or GABA(A) receptor levels. When combined with the authors' previous study on these same eagles that showed Hg-associated alterations in GS, GAD, and NMDA receptor levels, the present research suggests that bald eagles are exposed to various elements, especially Pb and Hg, that are capable of causing changes in GABAergic and glutamatergic neurotransmission. The functional significance of these neurochemical changes warrants attention. PMID:22170515

  19. Repair of a coracoid luxation and a tibiotarsal fracture in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Guzman, David Sanchez-Migallon; Bubenik, Loretta J; Lauer, Susanne K; Vasanjee, Sunil; Mitchell, Mark A

    2007-09-01

    A 4.5-kg, adult bald eagle (Haliaeetus leucocephalus) was presented after being found unable to fly. Crepitus was palpated in the left shoulder; however, the wing position was normal. Radiographs revealed caudoventral luxation of the left coracoid, affecting its distal articulation with the clavicle and its proximal articulation with the sternum. The luxation affecting the coracoid-sternum articulation was repaired by using a 4-hole, 1.5-mm T-plate and a 6-hole, 2.0-mm dynamic compression plate (DCP) placed side by side. The luxation affecting the coracoid and the clavicle was repaired by 2 cerclage wires in a simple interrupted pattern. Before a scheduled release, the bird sustained a closed, complete mid diaphyseal transverse fracture of the right tibiotarsus, which most likely occurred during recapture from the flight cage. The fracture was surgically repaired with 2 circumferential cerclage wires, an intramedullary Kirschner wire and one 10-hole, 2.7-mm DCP. The bird was successfully released, 105 days after the first surgery, near the location where it was found. PMID:18087935

  20. Chemotaxis of Flavobacterium columnare: To Channel Catfish Mucus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is the etiological agent of columnaris disease in fresh water fish. The disease is characterized by chronic skin lesions and severe mortality. The skin mucus constitutes a large portion of body and many infectious organisms including F. columnare, is believed to invade throu...

  1. Virulence of Flavobacterium columnare genomovars in rainbow trout Oncorhynchus mykiss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is the causative agent for columnaris disease and responsible for significant economic loss in the aquaculture industry. F. columnare is a gram negative bacteria with several genomovar classifications, based on the restriction fragment length polymorphism of the 16S rDNA gen...

  2. VIRULENCE OF Flavobacterium columnare GENOMOVARS IN RAINBOW TROUT (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is the causative agent of columnaris disease and is responsible for significant economic losses in aquaculture. F. columnare is a Gram-negative bacterium, and five genetic types or genomovars have been described based on restriction fragment length polymorphism of the 16S rR...

  3. Parasite treatment reduced Flavobacterium columnare infection in tilapia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterium Flavobacterium columnare and parasite Trichodina are common pathogens of cultured fish. The authors conducted a study to evaluate whether treatment of Trichodina parasitized tilapia with formalin would improve fish survival and reduce F. columnare infection in fish. Tilapia parasitized by...

  4. High-frequency micromechanical columnar resonators

    NASA Astrophysics Data System (ADS)

    Kehrbusch, Jenny; Ilin, Elena A.; Bozek, Peter; Radzio, Bernhard; Oesterschulze, Egbert

    2009-06-01

    High-frequency silicon columnar microresonators are fabricated using a simple but effective technological scheme. An optimized fabrication scheme was invented to obtain mechanically protected microcolumns with lateral dimensions controlled on a scale of at least 1 μm. In this paper, we investigate the influence of the environmental conditions on the mechanical resonator properties. At ambient conditions, we observed a frequency stability δf/f of less than 10-6 during 5 h of operation at almost constant temperature. However, varying the temperature shifts the frequency by approximately -173 Hz °C- 1. In accordance with a viscous damping model of the ambient gas, we perceived that the quality factor of the first flexural mode decreased with the inverse of the square root of pressure. However, in the low-pressure regime, a linear dependence was observed. We also investigated the influence of the type of the immersing gas on the resonant frequency.

  5. Columnar liquid crystals in cylindrical nanoconfinement.

    PubMed

    Zhang, Ruibin; Zeng, Xiangbing; Kim, Bongseock; Bushby, Richard J; Shin, Kyusoon; Baker, Patrick J; Percec, Virgil; Leowanawat, Pawaret; Ungar, Goran

    2015-02-24

    Axial orientation of discotic columnar liquid crystals in nanopores of inorganic templates, with the columns parallel to the axis of the nanochannels, is considered desirable for applications such as production of molecular wires. Here, we evaluate experimentally the role of the rigidity of the LC columns in achieving such orientation in nanopores where the planar anchoring (i.e., columns parallel to wall surface) is enforced. We studied the columnar phase of several discotic compounds with increasing column rigidity in the following order: dendronized carbazole, hexakis(hexyloxy)triphenylene (HAT6), a 1:1 HAT6-trinitrofluorenone (TNF) complex, and a helicene derivative. Using 2-D X-ray diffraction, AFM, grazing incidence diffraction, and polarized microscopy, we observed that the orientation of the columns changes from circular concentric to axial with increasing column rigidity. Additionally, when the rigidity is borderline, increasing pore diameter can change the configuration from axial back to circular. We derive expressions for distortion free energy that suggest that the orientation is determined by the competition between, on the one hand, the distortion energy of the 2-d lattice and the mismatch of its crystallographic facets with the curved pore wall in the axial orientation and, on the other hand, the bend energy of the columns in the circular configuration. Furthermore, the highly detailed AFM images of the core of the disclinations of strength +1 and +1/2 in the center of the pore reveal that the columns spiral down to the very center of the disclination and that there is no amorphous or misaligned region at the core, as suggested previously.

  6. Columnar structures from asymmetrically tapered biphenylamide.

    PubMed

    Park, Soo-Jin; Hwang, Seok-Ho; Kim, Namil; Kuo, Shiao-Wei; Kim, Hak Yong; Park, Seul-Ki; Kim, Young-Jin; Nah, Changwoon; Lee, Joong Hee; Jeong, Kwang-Un

    2009-10-15

    An asymmetrically tapered N,N'-tris[[(2-dodecylaminocarbonyl)ethyl]methyl]-4-biphenylamide (asym-C(12)PhA, where n is the number of carbon atoms in the alkyl chains, n = 12) was newly designed and synthesized. In this asymmetrically tapered asym-C(12)PhA biphenylamide, H-bondable hydrophilic amide moieties are located at between a rigid hydrophobic biphenyl rod and three flexible hydrophobic alkyl chains. Computer energy minimization indicated that three-dimensional (3D) geometry of asym-C(12)PhA biphenylamide looks like a cone with dimensions of 3.01 nm in height and 1.44 nm in bottom radius. Phase transitions and supra-molecular structures were identified utilizing the combined techniques of differential scanning calorimetry, 1D wide-angle X-ray diffraction (1D WAXD), Fourier-transform infrared spectroscopy, and solid-state (13)C nuclear magnetic resonance analyses. The asym-C(12)PhA self-assembled into a highly ordered columnar mesophase just below the isotropization temperature and then transformed to 3D columnar crystalline phase (Phi(Cr)) on further cooling. Selected area electron diffractions in transmission electron microscopy (TEM) along with 1D WAXD and cross-polarized optical microscopy suggested that discotic building blocks were constructed by rotating 120 degrees of three asym-C(12)PhA with respect to neighboring ones and the tmb (top-middle-bottom) stacked discotic building blocks further self-organized into columns. These columns are laterally intercalated to form the Phi(Cr) phase. On the basis of the TEM image and polyethylene surface decoration technology, it was identified that the self-assembled asym-C(12)PhA fibers with approximately 1 mum in diameter and several millimeters in length were braids of tiny single crystals.

  7. Columnar liquid crystals in cylindrical nanoconfinement.

    PubMed

    Zhang, Ruibin; Zeng, Xiangbing; Kim, Bongseock; Bushby, Richard J; Shin, Kyusoon; Baker, Patrick J; Percec, Virgil; Leowanawat, Pawaret; Ungar, Goran

    2015-02-24

    Axial orientation of discotic columnar liquid crystals in nanopores of inorganic templates, with the columns parallel to the axis of the nanochannels, is considered desirable for applications such as production of molecular wires. Here, we evaluate experimentally the role of the rigidity of the LC columns in achieving such orientation in nanopores where the planar anchoring (i.e., columns parallel to wall surface) is enforced. We studied the columnar phase of several discotic compounds with increasing column rigidity in the following order: dendronized carbazole, hexakis(hexyloxy)triphenylene (HAT6), a 1:1 HAT6-trinitrofluorenone (TNF) complex, and a helicene derivative. Using 2-D X-ray diffraction, AFM, grazing incidence diffraction, and polarized microscopy, we observed that the orientation of the columns changes from circular concentric to axial with increasing column rigidity. Additionally, when the rigidity is borderline, increasing pore diameter can change the configuration from axial back to circular. We derive expressions for distortion free energy that suggest that the orientation is determined by the competition between, on the one hand, the distortion energy of the 2-d lattice and the mismatch of its crystallographic facets with the curved pore wall in the axial orientation and, on the other hand, the bend energy of the columns in the circular configuration. Furthermore, the highly detailed AFM images of the core of the disclinations of strength +1 and +1/2 in the center of the pore reveal that the columns spiral down to the very center of the disclination and that there is no amorphous or misaligned region at the core, as suggested previously. PMID:25626118

  8. Direct numerical simulation of flow past cactus--shaped cylinders

    NASA Astrophysics Data System (ADS)

    Babu, Pradeep; Mahesh, Krishnan

    2006-11-01

    The Saguaro cacti are tall, have short root systems and can withstand high wind velocities (Bulk 1984, Talley et al. 2002). Their trunks are essentially cylindrical with V--shaped longitudinal cavities. The size and number of cavities on the Saguaro cacti vary so that they have a near--constant fraction cavity depth (l/D ratio of about 0.07, Geller & Nobel 1984). Direct numerical simulations is used to assess the aerodynamic effect of the grooves on the cactus. DNS is performed for cactus shaped cylinders with l/d ratio's of 0.07 and 0.105, and smooth cylinders (l/d=0) at the same Reynolds number. Presence of the V--shaped cavities is found to decrease the drag on the cylindrical trunk as well as affect the fluctuating lift forces. The talk will quantify these differences, and discuss the physical mechanisms by which V--shaped cavities on the surface influence the flow.

  9. Search for Dark Matter Annihilations in Draco with CACTUS

    SciTech Connect

    Chertok, M.; Afonso, P.; Lizarazo, J.; Marleau, P.; Maruyama, S.; Stilley, J.; Tripathi, S. M.

    2006-07-11

    CACTUS is a ground-based Air Cherenkov Telescope (ACT) at the Solar 2 facility located near Barstow, California, and operated by UC Davis. It uses an array of 160 large solar tracking mirrors (heliostats) and a camera with 80 photomultiplier tubes, which, in a multiplexed fashion provides an effective camera with about 300 channels. By incorporating novel techniques of time projection imaging and triggering, CACTUS improves upon the first generation sampling arrays of its kind. We have recently completed observations of Draco, a dwarf spheroidal galaxy that is known to be rich in dark matter content. Supersymmetry-inspired models for dark matter predict observable annihilation rates producing gamma rays. We present the first results from our Draco campaign.

  10. Kinks and Rotons in a Magnetic Cactus: Dynamical Phyllotaxis.

    NASA Astrophysics Data System (ADS)

    Nisoli, Cristiano; Monroe Gabor, Nathaniel; Crespi, Vincent Henry; Decatur Maynard, Julian

    2004-03-01

    The disposition of the leaves on a stem, spines on a cactus, seeds in a sunflower and other self-organized arrangements of repeated units in plant morphology, are denoted as phyllotaxis. Phyllotactic patterns are also found in polypeptide chains, cells of Bernard convection, and flux lattices in layered superconductors. Here we describe a "magnetic cactus," a model of interacting magnetic dipoles disposed along a cylindrical stem, based on the mechanical theory of phyllotaxis proposed by S. L. Levitov (1991). While the appearance of phyllotactic patterns in the static properties is well predicted by current theory, the dynamics bring new physics beyond that possible in biological systems: we demonstrate the formation and propagation of domain walls between stable structures, the number-theoretical properties that regulate their vibrational spectra, and show the appearence of what to our knowledge is the first example of classical rotons.

  11. The cuticle of the cactus Cereus peruvianus as a source of a homo-{alpha}-D-galacturonan

    SciTech Connect

    Alvarez, M.; Costa, S.C.; Huber, A.

    1995-12-31

    The waxy pecto-cellulosic cuticle of cladodes of the columnar cactus Cereus peruvianus (19% of the whole phytobiomass; dry wt) is a source of an {alpha}-D-polygalacturonic or pectic acid (35-40% yield, on a dry wt based on the wax-free pectocellulose layer). Warm EDTA/oxalate or room temperature strong acid/alkali cycles are efficient for pectic acid extraction, since divalent cation (mainly Ca{sup 2+}) is a barrier to be removed within the native and compact architecture of the cuticle. Despite some molecular dispersion arising from the application of strong mineral acid in the first extraction step, the pectic material appears to be quite homogeneous and, on acid or enzymatic analyses, was shown to contain only D-galacturonic acid as its monomer. Cereus cuticle pectate (sodium salt) tends to gel above a concentration of 1%, a useful property that can be more easily obtained by the inclusion of sucrose, light addition of calcium salt, and/or mild acidification.

  12. miRNA expression during prickly pear cactus fruit development.

    PubMed

    Rosas-Cárdenas, Flor de Fátima; Caballero-Pérez, Juan; Gutiérrez-Ramos, Ximena; Marsch-Martínez, Nayelli; Cruz-Hernández, Andrés; de Folter, Stefan

    2015-02-01

    miRNAs are a class of small non-coding RNAs that regulate gene expression. They are involved in the control of many developmental processes, including fruit development. The increasing amount of information on miRNAs, on their expression, abundance, and conservation between various species, provides a new opportunity to study the role of miRNAs in non-model plant species. In this work, we used a combination of Northern blot and tissue print hybridization analysis to identify conserved miRNAs expressed during prickly pear cactus (Opuntia ficus indica) fruit development. Comparative profiling detected the expression of 34 miRNAs, which were clustered in three different groups that were associated with the different phases of fruit development. Variation in the level of miRNA expression was observed. Gradual expression increase of several miRNAs was observed during fruit development, including miR164. miR164 was selected for stem-loop RT-PCR and for a detailed spatial-temporal expression analysis. At early floral stages, miR164 was mainly localized in meristematic tissues, boundaries and fusion zones, while it was more homogenously expressed in fruit tissues. Our results provide the first evidence of miRNA expression in the prickly pear cactus and provide the basis for future research on miRNAs in Opuntia. Moreover, our analyses suggest that miR164 plays different roles during prickly pear cactus fruit development.

  13. The flow past a cactus-inspired grooved cylinder

    NASA Astrophysics Data System (ADS)

    El-Makdah, Adnan M.; Oweis, Ghanem F.

    2013-02-01

    The star-shaped cross section of giant cylindrical cactus plants is thought to be aerodynamically favorable for protection against toppling by strong winds. Particle image velocimetry is used to investigate the flow details within the surface grooves and in the immediate wake of a cactus-inspired model cylinder with eight longitudinal grooves, at biologically relevant Reynolds numbers between 50 × 103 and 170 × 103. The wake flow is analyzed and compared to a similarly sized circular cylinder. At the lowest Re tested, the wakes from the two geometries are similar. At higher Re, the cactus wake exhibits superior behavior as seen from the mean and turbulent velocities, suggesting that the flow mechanisms are Re dependent. The flow within the surface grooves reveals counter rotating rollers, while the geometrical ridges act as vortex generators known to help with the surface flow attachment. Lastly, a simplistic analysis is described to recover, qualitatively, certain time-dependent flow features from the randomly acquired PIV realizations.

  14. miRNA expression during prickly pear cactus fruit development.

    PubMed

    Rosas-Cárdenas, Flor de Fátima; Caballero-Pérez, Juan; Gutiérrez-Ramos, Ximena; Marsch-Martínez, Nayelli; Cruz-Hernández, Andrés; de Folter, Stefan

    2015-02-01

    miRNAs are a class of small non-coding RNAs that regulate gene expression. They are involved in the control of many developmental processes, including fruit development. The increasing amount of information on miRNAs, on their expression, abundance, and conservation between various species, provides a new opportunity to study the role of miRNAs in non-model plant species. In this work, we used a combination of Northern blot and tissue print hybridization analysis to identify conserved miRNAs expressed during prickly pear cactus (Opuntia ficus indica) fruit development. Comparative profiling detected the expression of 34 miRNAs, which were clustered in three different groups that were associated with the different phases of fruit development. Variation in the level of miRNA expression was observed. Gradual expression increase of several miRNAs was observed during fruit development, including miR164. miR164 was selected for stem-loop RT-PCR and for a detailed spatial-temporal expression analysis. At early floral stages, miR164 was mainly localized in meristematic tissues, boundaries and fusion zones, while it was more homogenously expressed in fruit tissues. Our results provide the first evidence of miRNA expression in the prickly pear cactus and provide the basis for future research on miRNAs in Opuntia. Moreover, our analyses suggest that miR164 plays different roles during prickly pear cactus fruit development. PMID:25366556

  15. Corrective action investigation plan: Cactus Spring Waste Trenches. Revision 2

    SciTech Connect

    1997-02-01

    This Correction Action Investigation Plan (CAIP) contains environmental sample collection objectives and logic for the Corrective Action Unit No. 426, which includes the Cactus Spring Waste Trenches, located at the Tonopah Test Range. The purpose of this investigation is to generate sufficient data to establish the types of waste buried in the trenches, identify the presence and nature of contamination, determine the vertical extent of contaminant migration below the Cactus Spring Waste Trenches, and determine the appropriate course of action for the site. The potential courses of action for the site are clean closure, closure in place (with or without remediation), or no further action. The scope of this investigation will include drilling and collecting subsurface samples from within and below the trenches. Sampling locations will be biased toward the areas most likely to be contaminated. The Cactus Spring Waste Trenches Site is identified as one of three potential locations for buried, radioactively contaminated materials from the Double Tracks Test. This test was the first of four storage-transportation tests conducted in 1963 as part of Operation Roller Coaster. The experiment involved the use of live animals to assess the inhalation intake of a plutonium aerosol.

  16. Precambrian columnar stromatolite diversity: reflection of metazoan appearance.

    PubMed

    Awramik, S M

    1971-11-19

    Columnar stromatolites (organosedimentary structures built by bluegreen algae) show a marked decrease in diversity in the Late Precambrian; this decrease in diversity occurs at approximately the same time as the appearance of metazoans, 600 to 700 million years ago.

  17. Vaccination of fish against Flavobacterium columnare and F. psychrophilum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are two primary Flavobacterium spp. involved in disease of aquaculture raised fish worldwide including, F. columnare, and F. psychrophilum; the etiologic agents of columnaris disease and bacterial coldwater disease (CWD) or rainbow trout fry syndrome (RTFS), respectively. Traditional vaccines...

  18. Water hardness influences Flavobacterium columnare pathogenesis in channel catfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted to determine aspects of water chemistry responsible for large differences in pathogenesis and mortality rates in challenges of channel catfish Ictalurus punctatus with Flavobacterium columnare; challenges were conducted in water supplying the Stuttgart National Aquaculture Res...

  19. Development of methods for the genetic manipulation of Flavobacterium columnare

    PubMed Central

    Staroscik, Andrew M; Hunnicutt, David W; Archibald, Kate E; Nelson, David R

    2008-01-01

    Background Flavobacterium columnare is the causative agent of columnaris disease, a disease affecting many freshwater fish species. Methods for the genetic manipulation for some of the species within the Bacteroidetes, including members of the genus Flavobacterium, have been described, but these methods were not adapted to work with F. columnare. Results As a first step toward developing a robust set of genetic tools for F. columnare, a protocol was developed to introduce the E. coli – Flavobacterium shuttle vector pCP29 into F. columnare strain C#2 by conjugal mating at an efficiency of 1.5 × 10-3 antibiotic-resistant transconjugants per recipient cell. Eight of eleven F. columnare strains tested were able to receive pCP29 using the protocol. pCP29 contains the cfxA and ermF genes, conferring both cefoxitin and erythromycin resistance to recipient cells. Selection for pCP29 introduction into F. columnare was dependent on cfxA, as ermF was found not to provide strong resistance to erythromycin. This is in contrast to other Flavobacterium species where ermF-based erythromycin resistance is strong. The green fluorescent protein gene (gfp) was introduced into F. columnare strains under the control of two different native Flavobacterium promoters, demonstrating the potential of this reporter system for the study of gene expression. The transposon Tn4351 was successfully introduced into F. columnare, but the method was dependent on selecting for erythromycin resistance. To work, low concentrations of antibiotic (1 μg ml-1) were used, and high levels of background growth occurred. These results demonstrate that Tn4351 functions in F. columnare but that it is not an effective mutagenesis tool due to its dependence on erythromycin selection. Attempts to generate mutants via homologous recombination met with limited success, suggesting that RecA dependent homologous recombination is rare in F. columnare. Conclusion The conjugation protocol developed as part of this

  20. Introduced and invasive cactus species: a global review.

    PubMed

    Novoa, Ana; Le Roux, Johannes J; Robertson, Mark P; Wilson, John R U; Richardson, David M

    2014-12-03

    Understanding which species are introduced and become invasive, and why, are central questions in invasion science. Comparative studies on model taxa have provided important insights, but much more needs to be done to unravel the context dependencies of these findings. The cactus family (Cactaceae), one of the most popular horticultural plant groups, is an interesting case study. Hundreds of cactus species have been introduced outside their native ranges; a few of them are among the most damaging invasive plant species in the world. We reviewed the drivers of introductions and invasions in the family and seek insights that can be used to minimize future risks. We compiled a list of species in the family and determined which have been recorded as invasive. We also mapped current global distributions and modelled the potential global distributions based on distribution data of known invasive taxa. Finally, we identified whether invasiveness is phylogenetically clustered for cacti and whether particular traits are correlated with invasiveness. Only 57 of the 1922 cactus species recognized in this treatment have been recorded as invasive. There are three invasion hotspots: South Africa (35 invasive species recorded), Australia (26 species) and Spain (24 species). However, there are large areas of the world with climates suitable for cacti that are at risk of future invasion-in particular, parts of China, eastern Asia and central Africa. The invasive taxa represent an interesting subset of the total species pool. There is a significant phylogenetic signal: invasive species occur in 2 of the 3 major phylogenetic clades and in 13 of the 130 genera. This phylogenetic signal is not driven by human preference, i.e. horticultural trade, but all invasive species are from 5 of the 12 cactus growth forms. Finally, invasive species tend to have significantly larger native ranges than non-invasive species, and none of the invasive species are of conservation concern in their

  1. Field Survey of Cactus Crater Storage Facility (Runit Dome)

    SciTech Connect

    Douglas Miller, Terence Holland

    2008-10-31

    The US Department of Energy, Office of Health and Safety (DOE/HS-10), requested that National Security Technologies, LLC, Environmental Management directorate (NSTec/EM) perform a field survey of the Cactus Crater Storage Facility (Runit Dome), similar to past surveys conducted at their request. This field survey was conducted in conjunction with a Lawrence Livermore National Laboratory (LLNL) mission on Runit Island in the Enewetak Atoll in the Republic of the Marshall Islands (RMI). The survey was strictly a visual survey, backed up by digital photos and a written description of the current condition.

  2. Introduced and invasive cactus species: a global review

    PubMed Central

    Novoa, Ana; Le Roux, Johannes J.; Robertson, Mark P.; Wilson, John R.U.; Richardson, David M.

    2015-01-01

    Understanding which species are introduced and become invasive, and why, are central questions in invasion science. Comparative studies on model taxa have provided important insights, but much more needs to be done to unravel the context dependencies of these findings. The cactus family (Cactaceae), one of the most popular horticultural plant groups, is an interesting case study. Hundreds of cactus species have been introduced outside their native ranges; a few of them are among the most damaging invasive plant species in the world. We reviewed the drivers of introductions and invasions in the family and seek insights that can be used to minimize future risks. We compiled a list of species in the family and determined which have been recorded as invasive. We also mapped current global distributions and modelled the potential global distributions based on distribution data of known invasive taxa. Finally, we identified whether invasiveness is phylogenetically clustered for cacti and whether particular traits are correlated with invasiveness. Only 57 of the 1922 cactus species recognized in this treatment have been recorded as invasive. There are three invasion hotspots: South Africa (35 invasive species recorded), Australia (26 species) and Spain (24 species). However, there are large areas of the world with climates suitable for cacti that are at risk of future invasion—in particular, parts of China, eastern Asia and central Africa. The invasive taxa represent an interesting subset of the total species pool. There is a significant phylogenetic signal: invasive species occur in 2 of the 3 major phylogenetic clades and in 13 of the 130 genera. This phylogenetic signal is not driven by human preference, i.e. horticultural trade, but all invasive species are from 5 of the 12 cactus growth forms. Finally, invasive species tend to have significantly larger native ranges than non-invasive species, and none of the invasive species are of conservation concern in their

  3. Experimental investigation of the scaling of columnar joints.

    PubMed

    Goehring, Lucas; Morris, Stephen W; Lin, Zhenquan

    2006-09-01

    Columnar jointing is a fracture pattern common in igneous rocks in which cracks self-organize into a roughly hexagonal arrangement, leaving behind an ordered colonnade. We report observations of columnar jointing in a laboratory analog system, desiccated corn starch slurries. Using measurements of moisture density, evaporation rates, and fracture advance rates as evidence, we suggest that an advective-diffusive system is responsible for the rough scaling behavior of columnar joints. This theory explains the order of magnitude difference in scales between jointing in lavas and in starches. We investigated the scaling of average columnar cross-sectional areas due to the evaporation rate, the analog of the cooling rate of igneous columnar joints. We measured column areas in experiments where the evaporation rate depended on lamp height and time, in experiments where the evaporation rate was fixed using feedback methods, and in experiments where gelatin was added to vary the rheology of the starch. Our results suggest that the column area at a particular depth is related to both the current conditions, and hysteretically to the geometry of the pattern at previous depths. We argue that there exists a range of stable column scales allowed for any particular evaporation rate.

  4. Experimental investigation of the scaling of columnar joints.

    PubMed

    Goehring, Lucas; Morris, Stephen W; Lin, Zhenquan

    2006-09-01

    Columnar jointing is a fracture pattern common in igneous rocks in which cracks self-organize into a roughly hexagonal arrangement, leaving behind an ordered colonnade. We report observations of columnar jointing in a laboratory analog system, desiccated corn starch slurries. Using measurements of moisture density, evaporation rates, and fracture advance rates as evidence, we suggest that an advective-diffusive system is responsible for the rough scaling behavior of columnar joints. This theory explains the order of magnitude difference in scales between jointing in lavas and in starches. We investigated the scaling of average columnar cross-sectional areas due to the evaporation rate, the analog of the cooling rate of igneous columnar joints. We measured column areas in experiments where the evaporation rate depended on lamp height and time, in experiments where the evaporation rate was fixed using feedback methods, and in experiments where gelatin was added to vary the rheology of the starch. Our results suggest that the column area at a particular depth is related to both the current conditions, and hysteretically to the geometry of the pattern at previous depths. We argue that there exists a range of stable column scales allowed for any particular evaporation rate. PMID:17025716

  5. Experimental investigation of the scaling of columnar joints

    NASA Astrophysics Data System (ADS)

    Goehring, Lucas; Morris, Stephen W.; Lin, Zhenquan

    2006-09-01

    Columnar jointing is a fracture pattern common in igneous rocks in which cracks self-organize into a roughly hexagonal arrangement, leaving behind an ordered colonnade. We report observations of columnar jointing in a laboratory analog system, desiccated corn starch slurries. Using measurements of moisture density, evaporation rates, and fracture advance rates as evidence, we suggest that an advective-diffusive system is responsible for the rough scaling behavior of columnar joints. This theory explains the order of magnitude difference in scales between jointing in lavas and in starches. We investigated the scaling of average columnar cross-sectional areas due to the evaporation rate, the analog of the cooling rate of igneous columnar joints. We measured column areas in experiments where the evaporation rate depended on lamp height and time, in experiments where the evaporation rate was fixed using feedback methods, and in experiments where gelatin was added to vary the rheology of the starch. Our results suggest that the column area at a particular depth is related to both the current conditions, and hysteretically to the geometry of the pattern at previous depths. We argue that there exists a range of stable column scales allowed for any particular evaporation rate.

  6. Radiating columnar joints in Gyeongju, Korea as a educational site

    NASA Astrophysics Data System (ADS)

    Woo, H.; Kim, J. H.; Jang, Y. D.

    2015-12-01

    Gyeongju is located in the central eastern part of South Korea. There are various directional columnar joint sets in Tertiary trachytic basalt formation along the shore. In particular, rare radiating columnar joints occur in this area. Columnar joints are parallel, prismatic columns that are formed as a result of contraction during the rapid cooling of lava flow, forming a three dimensional fracture network. In general, the radius and direction of the rock column represent the cooling rate and surface respectively. Radiating direction of columns here indicates that dome- or lobe-shaped lava was cooled from its surface to the core during the viscous lava flow. The fact that the trachytic textures of plagioclase laths are indistinct suggests that the radiating columnar joints are equivalent to the frontal end of the lava lobes. This area is currently has a shore trail course, which is being developed into a picturesque educational park. There are corresponding information boards on the trail near each type of columnar joints to explain not only the forming process and geological mechanisms but the importance of nature conservation to visitors, especially students. A variety of educational materials and educational programs linked to regular school curriculum are also being developed.

  7. Betalain, Acid ascorbic, phenolic contents and antioxidant properties of purple, red, yellow and white cactus pears.

    PubMed

    Sumaya-Martínez, María Teresa; Cruz-Jaime, Sandra; Madrigal-Santillán, Eduardo; García-Paredes, Juan Diego; Cariño-Cortés, Raquel; Cruz-Cansino, Nelly; Valadez-Vega, Carmen; Martinez-Cardenas, Leonardo; Alanís-García, Ernesto

    2011-01-01

    Commercialization of cactus pears based on their antioxidant properties can generate competitive advantages, and these can turn into business opportunities and the development of new products and a high-value ingredient for the food industry. This work evaluated the antioxidant activities (1,1-diphenyl-2-picrylhydrazyl radical-scavenging, protection against oxidation of a β-carotene-linoleic acid emulsion, and iron (II) chelation), the content of total phenolic compounds, ascorbic acid, betacyanin, betaxanthin and the stability of betacyanin pigments in presence of Cu (II)-dependent hydroxyl radicals (OH•), in 18 cultivars of purple, red, yellow and white cactus pear from six Mexican states. Our results indicated that the antiradical activities from yellow and white cactus pear cultivars were not significantly different (p < 0.05) and were lower than the average antiradical activities in red and purple cultivars. The red cactus pear from the state of Zacatecas showed the highest antioxidant activity. The free radical scavenging activity for red cactus pears was significantly correlated (p < 0.05) to the concentration of total phenolic compounds (R(2) = 0.90) and ascorbic acid (R(2) = 0.86). All 18 cultivars of cactus pears studied showed significant chelating activity of ferrous ions. The red and purple cactus pears showed a great stability when exposed to OH•.

  8. Calpain A modulates Toll responses by limited Cactus/IκB proteolysis

    PubMed Central

    Fontenele, Marcio; Lim, Bomyi; Oliveira, Danielle; Buffolo, Márcio; Perlman, David H.; Schupbach, Trudi; Araujo, Helena

    2013-01-01

    Calcium-dependent cysteine proteases of the calpain family are modulatory proteases that cleave their substrates in a limited manner. Among their substrates, calpains target vertebrate and invertebrate IκB proteins. Because proteolysis by calpains potentially generates novel protein functions, it is important to understand how this affects NFκB activity. We investigate the action of Calpain A (CalpA) on the Drosophila melanogaster IκB homologue Cactus in vivo. CalpA alters the absolute amounts of Cactus protein. Our data indicate, however, that CalpA uses additional mechanisms to regulate NFκB function. We provide evidence that CalpA interacts physically with Cactus, recognizing a Cactus pool that is not bound to Dorsal, a fly NFκB/Rel homologue. We show that proteolytic cleavage by CalpA generates Cactus fragments lacking an N-terminal region required for Toll responsiveness. These fragments are generated in vivo and display properties distinct from those of full-length Cactus. We propose that CalpA targets free Cactus, which is incorporated into and modulates Toll-responsive complexes in the embryo and immune system. PMID:23864715

  9. Betalain, Acid Ascorbic, Phenolic Contents and Antioxidant Properties of Purple, Red, Yellow and White Cactus Pears

    PubMed Central

    Sumaya-Martínez, María Teresa; Cruz-Jaime, Sandra; Madrigal-Santillán, Eduardo; García-Paredes, Juan Diego; Cariño-Cortés, Raquel; Cruz-Cansino, Nelly; Valadez-Vega, Carmen; Martinez-Cardenas, Leonardo; Alanís-García, Ernesto

    2011-01-01

    Commercialization of cactus pears based on their antioxidant properties can generate competitive advantages, and these can turn into business opportunities and the development of new products and a high-value ingredient for the food industry. This work evaluated the antioxidant activities (1,1-diphenyl-2-picrylhydrazyl radical-scavenging, protection against oxidation of a β-carotene-linoleic acid emulsion, and iron (II) chelation), the content of total phenolic compounds, ascorbic acid, betacyanin, betaxanthin and the stability of betacyanin pigments in presence of Cu (II)-dependent hydroxyl radicals (OH•), in 18 cultivars of purple, red, yellow and white cactus pear from six Mexican states. Our results indicated that the antiradical activities from yellow and white cactus pear cultivars were not significantly different (p < 0.05) and were lower than the average antiradical activities in red and purple cultivars. The red cactus pear from the state of Zacatecas showed the highest antioxidant activity. The free radical scavenging activity for red cactus pears was significantly correlated (p < 0.05) to the concentration of total phenolic compounds (R2 = 0.90) and ascorbic acid (R2 = 0.86). All 18 cultivars of cactus pears studied showed significant chelating activity of ferrous ions. The red and purple cactus pears showed a great stability when exposed to OH•. PMID:22072899

  10. Magnetic resonance imaging is superior to radiography in evaluating spinal cord trauma in three bald eagles (Haliaeetus leucocephalus).

    PubMed

    Stauber, Erik; Holmes, Shannon; DeGhetto, Darlene L; Finch, Nickol

    2007-09-01

    Three bald eagles (Haliaeetus leucocephalus) found along highways and unable to fly were presented for evaluation. All eagles exhibited sternal recumbency, as well as flaccid hind limb and tail paralysis. Vertebral column and spinal cord trauma were suspected as the cause. One bird died, whereas the remaining 2 birds were stabilized for diagnostic imaging studies. All 3 birds were evaluated by radiography and magnetic resonance imaging (MRI) for diagnosis and for prognosis in the live birds. Radiographic findings in all 3 birds were inconclusive, whereas MRI results showed extensive damage of the spinal cord and vertebral column, precluding functional recovery. The 2 surviving birds were euthanatized. In all birds, MRI assessments correlated well with necropsy and histopathologic findings.

  11. A new species of Caryospora (Apicomplexa: Eimeriidae) from the bald eagle, Haliaeetus leucocephalus (Accipitriformes: Accipitridae), from Kansas.

    PubMed

    McAllister, Chris T; Duszynski, Donald W; McKown, Richard D

    2013-04-01

    Between March 1989 and February 1994, 4 bald eagles ( Haliaeetus leucocephalus ) from various localities in Kansas were examined for coccidia. One (25%) of the bald eagles was found to be passing an undescribed species of Caryospora in its feces. Oocysts of Caryospora hanebrinki n. sp. are ellipsoidal to ovoidal with a bilayered wall and measure 48.1 × 42.1 μm with a shape index of 1.2. A micropyle, oocyst residuum, and polar granule were absent. Sporocysts are spheroidal, 24.8 μm wide. Stieda, substieda, and parastieda bodies were absent; a spheroidal sporocyst residuum is present; it measures 17.5 μm and is composed of many intact homogenous globules with a few dispersed in a loose spiral around the sporocysts. This is the first caryosporan documented from the bald eagle and is the largest known Caryospora from raptors.

  12. Hematology and serum chemistries of nestling bald eagles (Haliaeetus leucocephalus) in the lower peninsula of MI, USA.

    PubMed

    Bowerman, W W; Stickle, J E; Giesy, J P

    2000-11-01

    Hematology constituents and serum biochemistries were determined in blood collected from 55 nestling bald eagles (Haliaeetus leucocephalus) from nest sites within the lower peninsula of Michigan in 1992. Hematological values were comparable to published ranges for birds for all but eosinophils, which were greater than normal. Serum chemistry values were similar to those of other birds for all but six parameters, uric acid, cholesterol, alkaline phosphatase, total protein, globulin, and urea nitrogen, which were greater and glucose which was less. Samples of blood collected from wild bald eagles can be used for hematologic parameters and serum chemistry. It is important for other studies of endangered species to obtain baseline data from healthy, wild animals in their natural environment, and for comparison of animals living in environments of greater exposure to those living in areas of lesser exposure to xenobiotics. We caution that arrangements for rapid analysis be done in advance of sample collection.

  13. Magnetic resonance imaging is superior to radiography in evaluating spinal cord trauma in three bald eagles (Haliaeetus leucocephalus).

    PubMed

    Stauber, Erik; Holmes, Shannon; DeGhetto, Darlene L; Finch, Nickol

    2007-09-01

    Three bald eagles (Haliaeetus leucocephalus) found along highways and unable to fly were presented for evaluation. All eagles exhibited sternal recumbency, as well as flaccid hind limb and tail paralysis. Vertebral column and spinal cord trauma were suspected as the cause. One bird died, whereas the remaining 2 birds were stabilized for diagnostic imaging studies. All 3 birds were evaluated by radiography and magnetic resonance imaging (MRI) for diagnosis and for prognosis in the live birds. Radiographic findings in all 3 birds were inconclusive, whereas MRI results showed extensive damage of the spinal cord and vertebral column, precluding functional recovery. The 2 surviving birds were euthanatized. In all birds, MRI assessments correlated well with necropsy and histopathologic findings. PMID:18087936

  14. A new species of Caryospora (Apicomplexa: Eimeriidae) from the bald eagle, Haliaeetus leucocephalus (Accipitriformes: Accipitridae), from Kansas.

    PubMed

    McAllister, Chris T; Duszynski, Donald W; McKown, Richard D

    2013-04-01

    Between March 1989 and February 1994, 4 bald eagles ( Haliaeetus leucocephalus ) from various localities in Kansas were examined for coccidia. One (25%) of the bald eagles was found to be passing an undescribed species of Caryospora in its feces. Oocysts of Caryospora hanebrinki n. sp. are ellipsoidal to ovoidal with a bilayered wall and measure 48.1 × 42.1 μm with a shape index of 1.2. A micropyle, oocyst residuum, and polar granule were absent. Sporocysts are spheroidal, 24.8 μm wide. Stieda, substieda, and parastieda bodies were absent; a spheroidal sporocyst residuum is present; it measures 17.5 μm and is composed of many intact homogenous globules with a few dispersed in a loose spiral around the sporocysts. This is the first caryosporan documented from the bald eagle and is the largest known Caryospora from raptors. PMID:22992168

  15. Anchoring transition in confined discotic columnar liquid crystal films

    NASA Astrophysics Data System (ADS)

    Brunet, Thomas; Thiebaut, Olivier; Charlet, Émilie; Bock, Harald; Kelber, Julien; Grelet, Éric

    2011-01-01

    We report the achievement of ultrathin films (down to 25 nm thick) of thermotropic columnar liquid crystals in homeotropic alignment (columns normal to the interface) confined between a glass slide and a thin metallic electrode (about 150 nm thick). The face-on orientation of the discotic compound is obtained by anchoring transition of a columnar liquid crystalline phase from a degenerate planar orientation to the homeotropic alignment without any phase transition to the isotropic liquid phase. The kinetic dependence on temperature of such anchoring transition is investigated revealing various diffusive growth regimes of the homeotropic domains. Finally, confining effects are also considered by varying the thickness of the columnar liquid crystal film to reach the typical value required in organic solar cells thus demonstrating the reliability of such alignment process in a photovoltaic context.

  16. COLUMNAR ORGANIZATION OF SPATIAL PHASE IN VISUAL CORTEX

    PubMed Central

    Wang, Yushi; Jin, Jianzhong; Kremkow, Jens; Lashgari, Reza; Komban, Stanley J.; Alonso, Jose M.

    2014-01-01

    Images are processed in the primary visual cortex by neurons that encode different stimulus orientations and spatial phases. In primates and carnivores, neighboring cortical neurons share similar orientation preferences but spatial phases were thought to be randomly distributed. Here we reveal a columnar organization for spatial phase in cats that shares resemblances with the columnar organization for orientation. For both orientation and phase, the mean difference across vertically aligned neurons was less than 1/4 of a cycle. Cortical neurons showed three times more diversity in phase than orientation preference, however, the average phase of local neuronal populations was similar through the depth of layer 4. We conclude that columnar organization for visual space is not only defined by the spatial location of the stimulus but also by absolute phase. Taken together with previous studies, our results suggest that this phase-visuotopy is responsible for the emergence of orientation maps. PMID:25420070

  17. Examination of Gunnison River influences on Cactus Park Lake Beds using Heavy Mineral and Geochemical Analyses

    NASA Astrophysics Data System (ADS)

    Schoepfer, S. D.; Benage, M. C.

    2008-12-01

    Unaweep Canyon is an enigmatic wind gap across the Uncompahgre Plateau in western Colorado. It is widely accepted that the ancestral Gunnison River once flowed through Unaweep Canyon and Cactus Park, a tributary to Unaweep Canyon. Newly discovered lake deposits in Cactus Park raise several important questions regarding the timing of events leading to the abandonment of Unaweep Canyon by the ancestral Gunnison River. Heavy minerals and trace elements of Cactus Park lake beds and ancestral Gunnison River sediments were compared to determine whether or not the ancestral Gunnison River was present at the time the Cactus Park Lake was filling with sediment. It is possible that the formation of this lake facilitated the eventual abandonment of Cactus Park and Unaweep Canyon by the ancestral Gunnison River. Alternatively, abandonment could have preceded the formation of the lake. In the latter scenario, the composition of the lake beds should differ significantly from modern or ancient Gunnison River deposits. Results of the analyses show that the Gunnison River and Cactus Park Lake samples form two distinct groups based on differences in elemental concentrations and heavy mineral percentages. Gunnison River sediments associated with volcanic terrains contain elevated copper and manganese concentrations with 7.5 times more manganese and 4.5 times more copper normalized to aluminum compared to samples of Mancos Shale. Mancos Shale is a likely source for the Cactus Park lake beds . These values would require the Cactus Park lake beds to be composed of 70-92 percent Mancos material,. The Gunnison River heavy mineral percentages are: total weathered grains (16.94-18.75), augite plus hornblende (21.43-32.26%), ZTR (31.45-32.14), hornblende (16.07-17.74%) and tourmaline (26.79-29.84%). Cactus Park lake bed samples have more weathered grains (26.56-46.83%), less augite plus hornblende (5.47-17.50), lower ZTR values (15.63-22.67), less hornblende (1.48-9.33%) and less tourmaline

  18. Cactus alkaloids. XXXVI. Mescaline and related compounds from Trichocereus peruvianus.

    PubMed

    Pardanani, J H; McLaughlin, J L; Kondrat, R W; Cooks, R G

    1977-01-01

    Agurell has previously detected (tlc, glc-ms) tyramine, 3-methoxytyramine, and two unknown alkaloids in the Peruvian cactus, Trichocereus peruvianus Br. and R. The presence of mescaline in other similar Trichocereus species prompted us to reinvestigate this species, which is commercially available in the United States. The nonphenolic alkaloid extracts yielded an abundance of crystalline mescaline hydrochloride (0.82% yield) and a trace of 3,4-dimethoxyphenethylamine (tlc-ms). Crystalline tyramine hydrochloride, 3-methoxytyramine hydrochloride, and 3,5 dimethoxy-4-hydroxphenethylamine hydrochloride were isolated from the phenolic alkaloid extracts; the last compound has not been previously crystallized from nature, although it is the immediate biosynthetic precursor of mescaline. Crystalline 2-chloromescaline hydrochloride was isolated drom the nonphenolic extracts; but, as determined by mass-analyzed ion kinetic energy spectrometry, this new compound is an extraction artifact. Both 2-chloromescaline and 2.6-dichloromescaline hydrochlorides were prepared synthetically from mescaline. This cactus species has a mescaline content equal or superior to peyote and should be legally controlled as an item of drug abuse.

  19. The population dynamics of an endemic collectible cactus

    NASA Astrophysics Data System (ADS)

    Mandujano, María C.; Bravo, Yolotzin; Verhulst, Johannes; Carrillo-Angeles, Israel; Golubov, Jordan

    2015-02-01

    Astrophytum is one of most collected genera in the cactus family. Around the world several species are maintained in collections and yearly, several plants are taken from their natural habitats. Populations of Astorphytum capricorne are found in the northern Chihuahuan desert, Mexico, and as many endemic cactus species, it has a highly restricted habitat. We conducted a demographic study from 2008 to 2010 of the northern populations found at Cuatro Ciénegas, Mexico. We applied matrix population models, included simulations, life table response experiments and descriptions of the population dynamics to evaluate the current status of the species, and detect key life table stages and demographic processes. Population growth rate decreased in both years and only 4% individual mortality can be attributed to looting, and a massive effort is needed to increase seedling recruitment and reduce adult mortality. The fate of individuals differed between years even having the same annual rainfall mainly in accentuated stasis, retrogression and high mortality in all size classes, which coupled with low seed production, no recruitment and collection of plants are the causes contributing to population decline, and hence, increase the risk in which A. capricorne populations are found. Reintroduction of seedlings and lowering adult mortality are urgently needed to revert the alarming demographic condition of A. capricorne populations.

  20. Trail Marking by Larvae of the Cactus Moth, Cactoblastis cactorum

    PubMed Central

    Fitzgerald, Terrence D.; Wolfin, Michael; Rossi, Frank; Carpenter, James E.; Pescador-Rubio, Alfonso

    2014-01-01

    The cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), spends most of its larval life feeding within the cladodes of Opuntia cactuses, but the gregarious caterpillars begin their life outside the plant, and in the later instars make intermittent excursions over plant surfaces to access new cladodes and to thermoregulate. The study reported here showed that when the caterpillars move en masse, they mark and follow trails that serve to keep the cohort together. Artificial trails prepared from hexane extracts of the caterpillar's paired mandibular glands were readily followed by the caterpillars. The glands are remarkably large, and their fluid contents, which constitute approximately 1% of the total wet mass of a caterpillar, are secreted onto the substrate as they move. Although the caterpillars also lay down copious quantities of silk, the material in itself neither elicits trail following nor is it a requisite component of pathways that elicit trail following. Previous analyses of the mandibular glands of other species of pyralid caterpillars showed that they contain a series of structurally distinct 2-acyl-1,3 cyclohexane diones. Chemical analysis indicates that the glands of C. cactorum contain structurally similar compounds, and bioassays indicate that trail following occurs in response to these chemicals. While the mandibular glands' fluids have been shown to act as semiochemicals, effecting both interspecific and intraspecific behavior in other species of pyralids, the present study is the first to report their use as a trail pheromone. PMID:25373211

  1. High frequency columnar silicon microresonators for mass detection

    SciTech Connect

    Kehrbusch, J.; Ilin, E. A.; Hullin, M.; Oesterschulze, E.

    2008-07-14

    A simple but effective technological scheme for the fabrication of high frequency silicon columnar microresonators is presented. With the proposed technique the dimensions of the microresonators are controlled on a scale of at least 1 {mu}m. Characterization of the mechanical properties of silicon columns gave resonant frequencies of the lowest flexural mode of 3-7 MHz with quality factors of up to 2500 in air and {approx}8800 under vacuum condition. Columnar microresonators were operated as mass balance with a sensitivity of 1 Hz/fg. A mass detection limit of 25 fg was deduced from experiments.

  2. On the scaling and ordering of columnar joints

    NASA Astrophysics Data System (ADS)

    Goehring, Lucas Allan Ziola

    Columnar jointing is a fracture pattern, best known from locations such as the Giant's Causeway, or Fingal's Cave, in which cracks self-organize into a nearly hexagonal arrangement, leaving behind an ordered colonnade. In this thesis observations of columnar jointing are reported from both a controlled laboratory setting, and in cooled lava flows. Experiments were performed in slurries of corn starch and water, which form columnar joints when dried. This drying process is examined in detail, and it is shown how desiccation leads to the propagation of a sharp shrinkage front. In general, but with some significant exceptions, the size of columnar joints is inversely dependent on the speed of this shrinkage front during their formation. The exceptions, which include sudden jumps in column scale, show that hysteresis is also important in choosing the column scale. Novel observations of the 3D structure of joints in starch show that columnar joints do not settle down to a perfect hexagonal pattern, but rather mature into a continuously evolving dynamic pattern. This pattern is scale invariant, and the same statistical distribution of column shapes applies equally to joints in both starch and lava. Field work was performed to study columnar jointing in the basalts of the Columbia River Basalt Group and the island of Staffa, and the more heterogeneous lava flows of Southwestern British Columbia. The widths of columns and the heights of striae (chisel-like markings that record details of cooling) were examined in detail, and these length scales are shown to be inversely proportional to each other. An additional length scale, that of wavy columns, is also first reported here. Based on these measurements, empirical advective-diffusive models are developed to describe the transport of water in a drying starch-cake, and the transport of heat in a cooling lava flow. These models have only a single scaling parameter, the Peclet number, which relates the fracture front velocity

  3. Plant population and habitat characteristics of the endemic Sonoran Desert cactus Peniocereus striatus in Organ Pipe Cactus National Monument, Arizona

    USGS Publications Warehouse

    Anderson, Greta; Rutman, Sue; Munson, Seth M.

    2010-01-01

    Peniocereus striatus (Brandegee) Buxb. (Cactaceae) is an endemic Sonoran Desert cactus that reaches its northern range limit in southwestern Arizona. One U.S. population occupies a small area of Organ Pipe Cactus National Monument near the U.S./Mexico international boundary, which has been monitored since 1939. An extensive survey conducted in 2002, covering 177 ha, resulted in the discovery of 88 new plants, in addition to the relocation of 57 plants found in previous surveys. Despite potential increases in population size and spatial distribution, mean plant height and number of basal stems has not significantly changed in recent years. Bud scars revealed that a majority of the population was sexually mature. Peniocereus striatus occurrence increased with decreasing slope, spanned every slope aspect, and was highest on rocky soils, but was noticeably low on west and northwest slopes and areas where severe land degradation had previously occurred. Over half of P. striatus plants were nursed by shrubs and subshrubs, while 40% occurred under leguminous trees. A severe frost in January 2002 top-killed 19% of the population, with the greatest damage in drainage bottoms. However, long-term (1944–2002) climate records show that there has been an overall increase in the number of frost free days in the region, which, coupled with land use change, has implications for the future health of this population.

  4. Physicochemical characterization of cactus pads from Opuntia dillenii and Opuntia ficus indica.

    PubMed

    Méndez, Lorena Pérez; Flores, Fidel Tejera; Martín, Jacinto Darias; Rodríguez Rodríguez, Elena M; Díaz Romero, Carlos

    2015-12-01

    Physicochemical characteristics (weight, length, width, thickness, moisture, Brix degree, total fiber, protein, ash, pH, acidity, ascorbic acid, total phenolic compounds, P, Na, K, Ca, Mg, Fe, Cu, Zn, Mn and Cr) were determined in cactus pads from Opuntia dillenii and Opuntia ficus indica. The physicochemical characteristics of both species were clearly different. There were important differences between the orange and green fruit pulp of O. ficus indica; the cactus pads of O. dillenii could be differentiated according to the region (North and South). Consumption of cactus pads contributes to the intake of dietary fiber, total phenolic compounds, K, Mg, Mn and Cr. Applying factor and/or discriminant analysis, the cactus pad samples were clearly differentiated according to the species, the fruit pulp color and production region. PMID:26041209

  5. Physicochemical characterization of cactus pads from Opuntia dillenii and Opuntia ficus indica.

    PubMed

    Méndez, Lorena Pérez; Flores, Fidel Tejera; Martín, Jacinto Darias; Rodríguez Rodríguez, Elena M; Díaz Romero, Carlos

    2015-12-01

    Physicochemical characteristics (weight, length, width, thickness, moisture, Brix degree, total fiber, protein, ash, pH, acidity, ascorbic acid, total phenolic compounds, P, Na, K, Ca, Mg, Fe, Cu, Zn, Mn and Cr) were determined in cactus pads from Opuntia dillenii and Opuntia ficus indica. The physicochemical characteristics of both species were clearly different. There were important differences between the orange and green fruit pulp of O. ficus indica; the cactus pads of O. dillenii could be differentiated according to the region (North and South). Consumption of cactus pads contributes to the intake of dietary fiber, total phenolic compounds, K, Mg, Mn and Cr. Applying factor and/or discriminant analysis, the cactus pad samples were clearly differentiated according to the species, the fruit pulp color and production region.

  6. Effect of ultrasound on survival and growth of Escherichia coli in cactus pear juice during storage.

    PubMed

    Cruz-Cansino, Nelly Del Socorro; Reyes-Hernández, Isidro; Delgado-Olivares, Luis; Jaramillo-Bustos, Diana Pamela; Ariza-Ortega, José Alberto; Ramírez-Moreno, Esther

    2016-01-01

    The aim of this study was to investigate the effectiveness of ultrasound as a conservation method for the inactivation of Escherichia coli inoculated into cactus pear juices (green and purple). Total soluble solids, pH, titratable acidity, and the kinetics of E. coli in cactus pear juices treated by ultrasound (60%, 70%, 80% and 90% amplitude levels for 1, 3 and 5min) were evaluated over 5 days. Total inactivation was observed in both fruit juices after 5min of ultrasound treatment at most amplitude levels (with the exception of 60% and 80%). After one and two days of storage, the recovery of bacteria counts was observed in all cactus pear juices. Ultrasound treatment at 90% amplitude for 5min resulted in non-detectable levels of E. coli in cactus pear juice for 2 days. The parameters of pH, titratable acidity and soluble solids were unaffected.

  7. Effect of ultrasound on survival and growth of Escherichia coli in cactus pear juice during storage.

    PubMed

    Cruz-Cansino, Nelly Del Socorro; Reyes-Hernández, Isidro; Delgado-Olivares, Luis; Jaramillo-Bustos, Diana Pamela; Ariza-Ortega, José Alberto; Ramírez-Moreno, Esther

    2016-01-01

    The aim of this study was to investigate the effectiveness of ultrasound as a conservation method for the inactivation of Escherichia coli inoculated into cactus pear juices (green and purple). Total soluble solids, pH, titratable acidity, and the kinetics of E. coli in cactus pear juices treated by ultrasound (60%, 70%, 80% and 90% amplitude levels for 1, 3 and 5min) were evaluated over 5 days. Total inactivation was observed in both fruit juices after 5min of ultrasound treatment at most amplitude levels (with the exception of 60% and 80%). After one and two days of storage, the recovery of bacteria counts was observed in all cactus pear juices. Ultrasound treatment at 90% amplitude for 5min resulted in non-detectable levels of E. coli in cactus pear juice for 2 days. The parameters of pH, titratable acidity and soluble solids were unaffected. PMID:26991288

  8. Seasonal photosynthetic gas exchange and water-use efficiency in a constitutive CAM plant, the giant saguaro cactus (Carnegiea gigantea).

    PubMed

    Bronson, Dustin R; English, Nathan B; Dettman, David L; Williams, David G

    2011-11-01

    Crassulacean acid metabolism (CAM) and the capacity to store large quantities of water are thought to confer high water use efficiency (WUE) and survival of succulent plants in warm desert environments. Yet the highly variable precipitation, temperature and humidity conditions in these environments likely have unique impacts on underlying processes regulating photosynthetic gas exchange and WUE, limiting our ability to predict growth and survival responses of desert CAM plants to climate change. We monitored net CO(2) assimilation (A(net)), stomatal conductance (g(s)), and transpiration (E) rates periodically over 2 years in a natural population of the giant columnar cactus Carnegiea gigantea (saguaro) near Tucson, Arizona USA to investigate environmental and physiological controls over carbon gain and water loss in this ecologically important plant. We hypothesized that seasonal changes in daily integrated water use efficiency (WUE(day)) in this constitutive CAM species would be driven largely by stomatal regulation of nighttime transpiration and CO(2) uptake responding to shifts in nighttime air temperature and humidity. The lowest WUE(day) occurred during time periods with extreme high and low air vapor pressure deficit (D(a)). The diurnal with the highest D(a) had low WUE(day) due to minimal net carbon gain across the 24 h period. Low WUE(day) was also observed under conditions of low D(a); however, it was due to significant transpiration losses. Gas exchange measurements on potted saguaro plants exposed to experimental changes in D(a) confirmed the relationship between D(a) and g(s). Our results suggest that climatic changes involving shifts in air temperature and humidity will have large impacts on the water and carbon economy of the giant saguaro and potentially other succulent CAM plants of warm desert environments. PMID:21822726

  9. Seasonal photosynthetic gas exchange and water-use efficiency in a constitutive CAM plant, the giant saguaro cactus (Carnegiea gigantea).

    PubMed

    Bronson, Dustin R; English, Nathan B; Dettman, David L; Williams, David G

    2011-11-01

    Crassulacean acid metabolism (CAM) and the capacity to store large quantities of water are thought to confer high water use efficiency (WUE) and survival of succulent plants in warm desert environments. Yet the highly variable precipitation, temperature and humidity conditions in these environments likely have unique impacts on underlying processes regulating photosynthetic gas exchange and WUE, limiting our ability to predict growth and survival responses of desert CAM plants to climate change. We monitored net CO(2) assimilation (A(net)), stomatal conductance (g(s)), and transpiration (E) rates periodically over 2 years in a natural population of the giant columnar cactus Carnegiea gigantea (saguaro) near Tucson, Arizona USA to investigate environmental and physiological controls over carbon gain and water loss in this ecologically important plant. We hypothesized that seasonal changes in daily integrated water use efficiency (WUE(day)) in this constitutive CAM species would be driven largely by stomatal regulation of nighttime transpiration and CO(2) uptake responding to shifts in nighttime air temperature and humidity. The lowest WUE(day) occurred during time periods with extreme high and low air vapor pressure deficit (D(a)). The diurnal with the highest D(a) had low WUE(day) due to minimal net carbon gain across the 24 h period. Low WUE(day) was also observed under conditions of low D(a); however, it was due to significant transpiration losses. Gas exchange measurements on potted saguaro plants exposed to experimental changes in D(a) confirmed the relationship between D(a) and g(s). Our results suggest that climatic changes involving shifts in air temperature and humidity will have large impacts on the water and carbon economy of the giant saguaro and potentially other succulent CAM plants of warm desert environments.

  10. Effects of Plant Size and Weather on the Flowering Phenology of the Organ Pipe Cactus (Stenocereus thurberi)

    PubMed Central

    Bustamante, Enriquena; Búrquez, Alberto

    2008-01-01

    Background and Aims Flowering phenology is a critical life-history trait that influences reproductive success. It has been shown that genetic, climatic and other factors such as plant size affect the timing of flowering and its duration. The spatial and temporal variation in the reproductive phenology of the columnar cactus Stenocereus thurberi and its association with plant size and environmental cues was studied. Methods Flowering was monitored during 3 years in three populations of S. thurberi along a latitudinal gradient. Plant size was related to phenological parameters. The actual and past weather were used for each site and year to investigate the environmental correlates of flowering. Key Results There was significant variation in the timing of flowering within and among populations. Flowering lasted 4 months in the southern population and only 2 months in the northern population. A single flowering peak was evident in each population, but ocurred at different times. Large plants produced more flowers, and bloomed earlier and for a longer period than small plants. Population synchrony increased as the mean duration of flowering per individual decreased. The onset of flowering is primarily related to the variance in winter minimum temperatures and the duration to the autumn–winter mean maximum temperature, whereas spring mean maximum temperature is best correlated with synchrony. Conclusions Plant size affects individual plant fecundity as well as flowering time. Thus the population structure strongly affects flowering phenology. Indications of clinal variation in the timing of flowering and reproductive effort suggest selection pressures related to the arrival of migrating pollinators, climate and resource economy in a desert environment. These pressures are likely to be relaxed in populations where individual plants can attain large sizes. PMID:18854374

  11. Columnar architecture improves noise robustness in a model cortical network.

    PubMed

    Bush, Paul C; Mainen, Zachary F

    2015-01-01

    Cortical columnar architecture was discovered decades ago yet there is no agreed upon explanation for its function. Indeed, some have suggested that it has no function, it is simply an epiphenomenon of developmental processes. To investigate this problem we have constructed a computer model of one square millimeter of layer 2/3 of the primary visual cortex (V1) of the cat. Model cells are connected according to data from recent paired cell studies, in particular the connection probability between pyramidal cells is inversely proportional both to the distance separating the cells and to the distance between the preferred parameters (features) of the cells. We find that these constraints, together with a columnar architecture, produce more tightly clustered populations of cells when compared to the random architecture seen in, for example, rodents. This causes the columnar network to converge more quickly and accurately on the pattern representing a particular stimulus in the presence of noise, suggesting that columnar connectivity functions to improve pattern recognition in cortical circuits. The model also suggests that synaptic failure, a phenomenon exhibited by weak synapses, may conserve metabolic resources by reducing transmitter release at these connections that do not contribute to network function.

  12. Nematic-columnar phase transition in oriented hard rectangles

    NASA Astrophysics Data System (ADS)

    Nath, Trisha; Dhar, Deepak; Rajesh, R.

    We consider an assembly of monodispersed hard rectangles of size 2 × d on a square lattice with only hard core interactions amongst them. The long axes of the rectangles can be oriented along the horizontal or vertical directions. For large enough aspect ratio, it is known that this system undergoes three phase transitions as the density (ρ) of rectangles is increased: first an isotropic-nematic transition (at ρ1*), second a nematic-columnar transition (at ρ2*), and third a columnar-sublattice transition (at ρ3*). In the nematic phase, only the orientational symmetry is broken. The columnar and sublattice phases correspond to additional broken translational symmetries along one (perpendicular to the nematic orientation) and both directions respectively. Interestingly, the critical value ρ2* remains finite, approximately 0 . 73 , even as d --> ∞ . We develop a systematic high density expansion for the surface tension between two differently-ordered columnar phases. Keeping only the first order perturbative correction term and setting this surface tension to zero, we get an estimate of ρ2* in excellent agreement with estimates from Monte Carlo simulations, for all d >= 2 .

  13. Columnar organization of orientation domains in V1

    NASA Astrophysics Data System (ADS)

    Liedtke, Joscha; Wolf, Fred

    In the primary visual cortex (V1) of primates and carnivores, the functional architecture of basic stimulus selectivities appears similar across cortical layers (Hubel & Wiesel, 1962) justifying the use of two-dimensional cortical models and disregarding organization in the third dimension. Here we show theoretically that already small deviations from an exact columnar organization lead to non-trivial three-dimensional functional structures. We extend two-dimensional random field models (Schnabel et al., 2007) to a three-dimensional cortex by keeping a typical scale in each layer and introducing a correlation length in the third, columnar dimension. We examine in detail the three-dimensional functional architecture for different cortical geometries with different columnar correlation lengths. We find that (i) topological defect lines are generally curved and (ii) for large cortical curvatures closed loops and reconnecting topological defect lines appear. This theory extends the class of random field models by introducing a columnar dimension and provides a systematic statistical assessment of the three-dimensional functional architecture of V1 (see also (Tanaka et al., 2011)).

  14. Laminar and columnar auditory cortex in avian brain

    PubMed Central

    Wang, Yuan; Brzozowska-Prechtl, Agnieszka; Karten, Harvey J.

    2010-01-01

    The mammalian neocortex mediates complex cognitive behaviors, such as sensory perception, decision making, and language. The evolutionary history of the cortex, and the cells and circuitry underlying similar capabilities in nonmammals, are poorly understood, however. Two distinct features of the mammalian neocortex are lamination and radially arrayed columns that form functional modules, characterized by defined neuronal types and unique intrinsic connections. The seeming inability to identify these characteristic features in nonmammalian forebrains with earlier methods has often led to the assumption of uniqueness of neocortical cells and circuits in mammals. Using contemporary methods, we demonstrate the existence of comparable columnar functional modules in laminated auditory telencephalon of an avian species (Gallus gallus). A highly sensitive tracer was placed into individual layers of the telencephalon within the cortical region that is similar to mammalian auditory cortex. Distribution of anterograde and retrograde transportable markers revealed extensive interconnections across layers and between neurons within narrow radial columns perpendicular to the laminae. This columnar organization was further confirmed by visualization of radially oriented axonal collaterals of individual intracellularly filled neurons. Common cell types in birds and mammals that provide the cellular substrate of columnar functional modules were identified. These findings indicate that laminar and columnar properties of the neocortex are not unique to mammals and may have evolved from cells and circuits found in more ancient vertebrates. Specific functional pathways in the brain can be analyzed in regard to their common phylogenetic origins, which introduces a previously underutilized level of analysis to components involved in higher cognitive functions. PMID:20616034

  15. Investigations of electromagnetic scattering by columnar ice crystals

    NASA Technical Reports Server (NTRS)

    Weil, H.; Senior, T. B. A.

    1976-01-01

    An integral equation approach was developed to determine the scattering and absorption of electromagnetic radiation by thin walled cylinders of arbitrary cross-section and refractive index. Based on this method, extensive numerical data was presented at infrared wavelengths for hollow hexagonal cross section cylinders which simulate columnar sheath ice crystals.

  16. Flavobacterium Columnare studies in rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare (Fc) is the causative agent for columnaris disesase and is a problem for several fish species. Recently, columnaris has been recognized as an emerging problem in farmed trout cultured within the Hagerman valley of Idaho. The aim of this study was two-fold. First determine...

  17. Ungeremine and its hemisynthetic analogues as bactericides against Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Gram-negative bacterium Flavobacterium columunare is the cause of colmunaris disease in channel catfish (Ictalurus punctatus). In a previous study, the betaine-type alkaloid ungeremine, 1 obtained from Pancratium maritimum L. was found to have strong antibacterial activity against F. columnare. ...

  18. Parasitism by Ich enhanced susceptibility of tilapia to Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In aquaculture systems, fish are commonly infected by two or more pathogens. Bacterium Flavobacterium columnare and parasite Ichthyophthirius multifiliis (Ich) are two common pathogens of cultured fish and result in heavy economic losses for aquaculture. There is no published information available ...

  19. Shock-induced effects in calcite from Cactus Crater

    NASA Technical Reports Server (NTRS)

    Vizgirda, J.; Ahrens, T. J.; Tsay, F.-D.

    1980-01-01

    The paper discusses shock metamorphism of calcite from coralline limestone samples retrieved from a borehole drilled into rocks beneath Cactus Crater, a nuclear explosion crater at Eniwetok Atoll. The metamorphism was detected and quantified using electron spin resonance (ESR); the ESR spectra of Mn(+) present as a trace constituent in the coral samples, show a consistent decrease in hyperfine peak splitting with decreasing depth of sample. It is suggested that the decrease in hyperfine peak splitting reflects a decrease in crystal field splitting, and therefore, small increases on cation-anion distances produced by mechanical energy input during the shock process. Two alternative crater models suggested by the ESR results are a depiction of a steady decay of the shock wave, and a delineation of a breccia lens with a breccia-bedrock interface at 20 plus or minus 5 m.

  20. Occupational type I allergy to Christmas cactus (Schlumbergera).

    PubMed

    Paulsen, E; Skov, P S; Bindslev-Jensen, C; Voitenko, V; Poulsen, L K

    1997-06-01

    The study aimed to determine whether occupational contact urticaria and symptoms of mucous membranes, reported by five workers in a cactus nursery, were due to IgE-mediated allergy to Schlumbergera cacti. The five persons had positive skin prick tests to the plants as is and positive histamine-release tests, and in three of them specific IgE to the cacti could be demonstrated by Maxisorp RAST and immunoblotting. Four of the patients were atopic, and the fifth had a positive skin prick test to cat dander, indicating latent atopy. Skin prick tests with cacti were negative in most atopic volunteers, and all had negative histamine-release tests. The results suggest a true IgE-mediated allergy to the cacti, and both genetic predisposition and close contact with the plants at work seem to be important factors in the emergence of this new occupational allergy.

  1. Columnar mesophases of hexabenzocoronene derivatives. II. Charge carrier mobility

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, James; Marcon, Valentina; Kremer, Kurt; Nelson, Jenny; Andrienko, Denis

    2008-09-01

    Combining atomistic molecular dynamic simulations, Marcus-Hush theory description of charge transport rates, and master equation description of charge dynamics, we correlate the temperature-driven change of the mesophase structure with the change of charge carrier mobilities in columnar phases of hexabenzocoronene derivatives. The time dependence of fluctuations in transfer integrals shows that static disorder is predominant in determining charge transport characteristics. Both site energies and transfer integrals are distributed because of disorder in the molecular arrangement. It is shown that the contributions to the site energies from polarization and electrostatic effects are of opposite sign for positive charges. We look at three mesophases of hexabenzocoronene: herringbone, discotic, and columnar disordered. All results are compared to time resolved microwave conductivity data and show excellent agreement with no fitting parameters.

  2. Columnar grown copper films on polyimides strained beyond 100%

    PubMed Central

    Sun, Jeong-Yun; Lee, Hae-Ryung; Hwan Oh, Kyu

    2015-01-01

    Many flexible electronic devices contain metal films on polymer substrates to satisfy requirements for both electrical conductivity and mechanical durability. Despite numerous trials to date, the stretchability of metal interconnects remains an issue. In this paper, we have demonstrated a stretchable metal interconnect through control of the texture of a copper film with columnar grown grains on a polyimide (PI) substrate. The columnar grown copper films (CGC films) were deposited by regulating radio frequency (RF) sputtering powers. CGC films were able to sustain their electrical conductivity at strains above 100%. Instead of ultimate electrical discontinuity by channel crack propagation, CGC films maintained their conductivity by forming ligament structures, or a ‘conductive net,’ through trapped micro-cracks. XRD, AFM and in situ SEM analysis were used to investigate these stretchable conductors. PMID:26337668

  3. Numerical Investigation of Buoyancy-Induced Columnar Vortices

    NASA Astrophysics Data System (ADS)

    Malaya, Nicholas; Stogner, Roy; Moser, Robert

    2014-11-01

    Buoyancy driven columnar vortices arise naturally in the atmosphere. A new energy harvesting approach makes use of this phenomenon by creating and anchoring the vortices artificially and extracting energy from them. In this talk, we explore the characteristics of these ``solar vortices'' through numerical simulation. Computational models of the turning vane system used to generate the solar vortex and the turbine used to extract energy have been developed. The formulation of these models and their validation against available experimental measurements will be discussed, as will the details of the columnar vortex structure and its interaction with the turbine. In addition, the computational models are being used to optimize the turning vane configuration and the turbine characteristics to maximize the power extraction, and to characterize the effects of environmental conditions such as cross winds and topography. Preliminary results from these studies will also be presented. This work supported by the Department of Energy [ARPA-E] under Award Number [DE-FOA-0000670].

  4. Solvent effect on columnar formation in solar-cell geometry

    NASA Astrophysics Data System (ADS)

    Park, J. H.; Sosa-Vargas, L.; Takanishi, Y.; Kim, K. H.; Kim, Y. S.; Park, Y. W.; Yamamoto, J.; Labardi, M.; Lagerwall, J. P. F.; Shimizu, Y.; Scalia, G.

    2016-03-01

    The efficiency of the conduction of photocurrent in discotic liquid crystals is known to depend on the quality of the columnar organization. Solvents have shown to be able to influence the formation of wire structures on substrates promoting very long and ordered wired formations or bulkier structures depending on the affinity of the solvent with parts of the molecular structure of discotics. Here we present a study on the effect of solvents when the liquid crystal is confined between two substrates with the columns running perpendicular to them, geometry used in solar cells. We focused on toluene and dodecane, solvents that have shown to promote on substrates the formation of aligned and long nanowires and bulk large and isolated fibers, respectively. The phase transition behavior indicates that toluene does not interfere with the columnar formation while dodecane strongly influence increasing the disorder in the structure.

  5. A rapid postmortem screening test for lead toxicosis in common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus).

    PubMed

    Kornetsky, Rachel; Rock, Meagan; Pokras, Mark

    2013-07-01

    In live animals, lead poisoning can be diagnosed by analyzing blood samples. For postmortem testing, blood samples are not available and analysis of liver or kidney is often used for diagnosis. Liver and kidney analysis is relatively expensive and results might not be quickly available. We examined an inexpensive, rapid method to screen animals for lead toxicosis postmortem by testing the mixture of body fluids (termed "tissue fluids") that pool in the body cavity at necropsy for lead. At necropsy we collected body fluid and liver samples from Common Loon (Gavia immer) and Bald Eagle (Haliaeetus leucocephalus) carcasses and determined concentrations of lead in tissue fluid using a desk-top blood lead analyzer. Concentrations of lead in liver were determined by inductively coupled plasma mass spectroscopy. There was strong correlation between tissue fluid and liver tissue lead concentrations, and receiver-operating characteristic analysis gave an area under the curve of 0.91, indicating that postmortem measurements of lead in tissue fluids can be utilized as a screening method for lead toxicosis.

  6. Mercury residues in livers of bald eagles (Haliaeetus leucocephalus) found dead or dying in British Columbia, Canada (1987-1994).

    PubMed

    Weech, S A; Wilson, L K; Langelier, K M; Elliott, J E

    2003-11-01

    Postmortem examinations were conducted on 82 bald eagles (Haliaeetus leucocephalus) found dead or dying in British Columbia, Canada, from 1987 to 1994. As part of the examination, livers were analyzed for total mercury (Hg) content, as well as methylmercury (meHg) and selenium (Se) in selected individuals. In total, 67 eagles were classed as having low Hg exposure [total Hg liver residues ranging from 0.5 to 17.2 mg/kg dry weight (dw)]. Fourteen eagles were moderately exposed (liver residues ranging from 19.2 to 36.8 mg/kg Hg dw). One eagle was judged to have died of Hg poisoning, with a total liver Hg content of 130.3 mg/kg dw, of which approximately 77% was meHg. The poisoned eagle and most of the exposed eagles were found in locations where effluent from pulp and paper processing plants is discharged along the British Columbia coast. In total, 6% of eagles examined died as a result of acute metal toxicosis (one from Hg poisoning, four from lead poisoning), in comparison to 72% dying from trauma (electrocution, vehicle/power line collision, eagle attack, trap, gunshot, drowning, and asphyxiation) and 11% from disease. The cause of death was undetermined in the remaining 11% of eagles.

  7. Reference intervals, longitudinal analyses, and index of individuality of commonly measured laboratory variables in captive bald eagles (Haliaeetus leucocephalus).

    PubMed

    Jones, Michael P; Arheart, Kristopher L; Cray, Carolyn

    2014-06-01

    The objectives of this study were to determine reference intervals, perform longitudinal analyses, and determine the index of individuality (IoI) of 8 hematologic, and 13 biochemical and electrophoretic variables for a group of captive bald eagles (Haliaeetus leucocephalus). Reference intervals were determined from blood samples collected during annual wellness examinations for 41 eagles (23 male and 18 female) with ages ranging between 6 and 43 years (18.7 +/- 7.4, mean +/- SD) at the time of sample collection. Longitudinal analyses and IoI were determined for measured hematologic, biochemical, and protein electrophoretic variables, both individually and as a group, for a subset of 16 eagles (10 male and 6 female) during a 12-year period. This smaller group of eagles ranged in age between 2 and 20 years at the start of the study period, and between 14 and 32 years (21.9 +/- 5.0, mean +/- SD) at the end of the study period. Significant increases with age within the group of 16 eagles were observed only for red blood cells, percent heterophils, total protein, and beta-globulin protein fraction, while albumin:globulin decreased significantly with age. A low IoI (> or = 1.4) was determined for all hematologic and biochemical variables except gamma globulins, which had high IoI (< or = 0.6) for 3 individuals within the subset of 16.

  8. Normal ocular parameters and characterization of ophthalmic lesions in a group of captive bald eagles (Haliaeetus leucocephalus).

    PubMed

    Kuhn, Sonia E; Jones, Michael P; Hendrix, Diane V H; Ward, Daniel A; Baine, Katherine H

    2013-06-01

    Sixteen adult captive bald eagles (Haliaeetus leucocephalus) underwent a complete bilateral ocular examination to assess normal ocular parameters and describe ophthalmic lesions. Tear production was measured with the Schirmer tear test 1 and intraocular pressure was measured with applanation tonometry. The menace response was normal bilaterally in 13 of 16 eagles. Two birds had normal menace responses despite having fundic lesions, and 2 birds with an inconsistent or absent menace response did not have appreciable ophthalmic lesions. Mean (SD) tear production was 14 +/- 2 mm/min (range, 8-19 mm/min). Mean intraocular pressure was 21.5 +/- 1.7 mm Hg (range, 15-26 mm Hg). At least 1 ocular lesion was present in 50% of examined eyes. Cataracts, the most common lesion observed, were present in 8 eyes of 5 birds. Three of 4 known geriatric birds were or had been affected with bilateral cataracts. Overall, ocular lesions are common in captive bald eagles, and cataracts appear to be more prevalent in geriatric bald eagles. An obvious positive menace response is present in most visual birds but may be absent in some eagles that are either normal or that do not have appreciable ophthalmic lesions. Applanation tonometry and the Schirmer tear test 1 can be performed easily on adult bald eagles and provide reproducible results.

  9. Normal ocular parameters and characterization of ophthalmic lesions in a group of captive bald eagles (Haliaeetus leucocephalus).

    PubMed

    Kuhn, Sonia E; Jones, Michael P; Hendrix, Diane V H; Ward, Daniel A; Baine, Katherine H

    2013-06-01

    Sixteen adult captive bald eagles (Haliaeetus leucocephalus) underwent a complete bilateral ocular examination to assess normal ocular parameters and describe ophthalmic lesions. Tear production was measured with the Schirmer tear test 1 and intraocular pressure was measured with applanation tonometry. The menace response was normal bilaterally in 13 of 16 eagles. Two birds had normal menace responses despite having fundic lesions, and 2 birds with an inconsistent or absent menace response did not have appreciable ophthalmic lesions. Mean (SD) tear production was 14 +/- 2 mm/min (range, 8-19 mm/min). Mean intraocular pressure was 21.5 +/- 1.7 mm Hg (range, 15-26 mm Hg). At least 1 ocular lesion was present in 50% of examined eyes. Cataracts, the most common lesion observed, were present in 8 eyes of 5 birds. Three of 4 known geriatric birds were or had been affected with bilateral cataracts. Overall, ocular lesions are common in captive bald eagles, and cataracts appear to be more prevalent in geriatric bald eagles. An obvious positive menace response is present in most visual birds but may be absent in some eagles that are either normal or that do not have appreciable ophthalmic lesions. Applanation tonometry and the Schirmer tear test 1 can be performed easily on adult bald eagles and provide reproducible results. PMID:23971217

  10. A rapid postmortem screening test for lead toxicosis in common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus).

    PubMed

    Kornetsky, Rachel; Rock, Meagan; Pokras, Mark

    2013-07-01

    In live animals, lead poisoning can be diagnosed by analyzing blood samples. For postmortem testing, blood samples are not available and analysis of liver or kidney is often used for diagnosis. Liver and kidney analysis is relatively expensive and results might not be quickly available. We examined an inexpensive, rapid method to screen animals for lead toxicosis postmortem by testing the mixture of body fluids (termed "tissue fluids") that pool in the body cavity at necropsy for lead. At necropsy we collected body fluid and liver samples from Common Loon (Gavia immer) and Bald Eagle (Haliaeetus leucocephalus) carcasses and determined concentrations of lead in tissue fluid using a desk-top blood lead analyzer. Concentrations of lead in liver were determined by inductively coupled plasma mass spectroscopy. There was strong correlation between tissue fluid and liver tissue lead concentrations, and receiver-operating characteristic analysis gave an area under the curve of 0.91, indicating that postmortem measurements of lead in tissue fluids can be utilized as a screening method for lead toxicosis. PMID:23778630

  11. Reference intervals, longitudinal analyses, and index of individuality of commonly measured laboratory variables in captive bald eagles (Haliaeetus leucocephalus).

    PubMed

    Jones, Michael P; Arheart, Kristopher L; Cray, Carolyn

    2014-06-01

    The objectives of this study were to determine reference intervals, perform longitudinal analyses, and determine the index of individuality (IoI) of 8 hematologic, and 13 biochemical and electrophoretic variables for a group of captive bald eagles (Haliaeetus leucocephalus). Reference intervals were determined from blood samples collected during annual wellness examinations for 41 eagles (23 male and 18 female) with ages ranging between 6 and 43 years (18.7 +/- 7.4, mean +/- SD) at the time of sample collection. Longitudinal analyses and IoI were determined for measured hematologic, biochemical, and protein electrophoretic variables, both individually and as a group, for a subset of 16 eagles (10 male and 6 female) during a 12-year period. This smaller group of eagles ranged in age between 2 and 20 years at the start of the study period, and between 14 and 32 years (21.9 +/- 5.0, mean +/- SD) at the end of the study period. Significant increases with age within the group of 16 eagles were observed only for red blood cells, percent heterophils, total protein, and beta-globulin protein fraction, while albumin:globulin decreased significantly with age. A low IoI (> or = 1.4) was determined for all hematologic and biochemical variables except gamma globulins, which had high IoI (< or = 0.6) for 3 individuals within the subset of 16. PMID:25115040

  12. Isolation of microsatellite loci and reliable genotyping using noninvasive samples of a critically endangered primate, Trachypithecus leucocephalus.

    PubMed

    Wang, Weiran; Qiao, Yu; Zheng, Yitao; Yao, Meng

    2016-07-01

    Genetic information can be critical in identifying conservation priorities and developing conservation strategies. There is an urgent need for noninvasive genetic tools to study the wild populations of Asian colobine monkeys. The majority of these species are threatened with habitat destruction, population reduction and even extinction, but generally lack information on their genetic diversity and population structure. Genetic sampling and tissue collection have been scarce in these species owing to strict regulations on manipulation of endangered species, and the difficulties and risks associated with capturing these arboreal and fast-moving monkeys in the challenging environments that they inhabit. These difficulties have hindered the development of molecular genetic markers, which are usually derived from tissues or blood. In this study, we present a method for de novo microsatellite isolation and genotyping using DNA from noninvasive origins of a critically endangered Asian colobine, the white-headed langur (Trachypithecus leucocephalus). Genomic DNA isolated from hair was shown to be sufficient for microsatellite enrichment and isolation, with similar isolation efficiencies as from tissue DNA. We identified and characterized 20 polymorphic microsatellite loci, and evaluated their amplification success and genotyping reliability with 86 field-collected fecal samples. These results show that this panel of loci can produce reliable genotypes from fecal samples, and represent a useful tool for noninvasive investigation of genetic structure, individual identification and kinship assessment in this highly endangered species. Our approach can be applied to conservation genetic studies of other wild species that lack sequence information and tissue samples.

  13. Quantum depinning of flux lines from columnar defects

    SciTech Connect

    Chudnovsky, E.M. ); Ferrera, A.; Vilenkin, A. )

    1995-01-01

    The depinning of a flux line from a columnar defect is studied within the path-integral approach. Instantons of the quantum field theory in 1+1 dimensions are computed for the flux line whose dynamics is dominated by the Magnus force. The universal temperature dependence of the decay rate in the proximity of the critical current is obtained. This problem provides an example of macroscopic quantum tunneling, which is accessible to the direct comparison between theory and experiment.

  14. Modular columnar supramolecular polymers as scaffolds for biomedical applications.

    PubMed

    Petkau-Milroy, Katja; Sonntag, Michael H; Brunsveld, Luc

    2013-08-12

    Self-assembly of discotic molecules into supramolecular polymers offers a flexible approach for the generation of multicomponent one-dimensional columnar architectures with tuneable biomedical properties. Decoration with ligands induces specific binding of the self-assembled scaffold to biological targets. The modular design allows the easy co-assembly of different discotics for the generation of probes for targeted imaging and cellular targeting with adjustable ligand density and composition.

  15. Virulence of Flavobacterium columnare genomovars in rainbow trout Oncorhynchus mykiss.

    PubMed

    Evenhuis, Jason P; LaFrentz, Benjamin R

    2016-08-01

    Flavobacterium columnare is the causative agent of columnaris disease and is responsible for significant economic losses in aquaculture. F. columnare is a Gram-negative bacterium, and 5 genetic types or genomovars have been described based on restriction fragment length polymorphism of the 16S rRNA gene. Previous research has suggested that genomovar II isolates are more virulent than genomovar I isolates to multiple species of fish, including rainbow trout Oncorhynchus mykiss. In addition, improved genotyping methods have shown that some isolates previously classified as genomovar I, and used in challenge experiments, were in fact genomovar III. Our objective was to confirm previous results with respect to genomovar II virulence, and to determine the susceptibility of rainbow trout to other genomovars. The virulence of 8 genomovar I, 4 genomovar II, 3 genomovar II-B, and 5 genomovar III isolates originating from various sources was determined through 3 independent challenges in rainbow trout using an immersion challenge model. Mean cumulative percent mortality (CPM) of ~49% for genomovar I isolates, ~1% for genomovar II, ~5% for the II-B isolates, and ~7% for the III isolates was observed. The inability of genomovar II isolates to produce mortalities in rainbow trout was unanticipated based on previous studies, but may be due to a number of factors including rainbow trout source and water chemistry. The source of fish and/or the presence of sub-optimal environment may influence the susceptibility of rainbow trout to different F. columnare genomovars. PMID:27503917

  16. Virulence of Flavobacterium columnare genomovars in rainbow trout Oncorhynchus mykiss.

    PubMed

    Evenhuis, Jason P; LaFrentz, Benjamin R

    2016-08-01

    Flavobacterium columnare is the causative agent of columnaris disease and is responsible for significant economic losses in aquaculture. F. columnare is a Gram-negative bacterium, and 5 genetic types or genomovars have been described based on restriction fragment length polymorphism of the 16S rRNA gene. Previous research has suggested that genomovar II isolates are more virulent than genomovar I isolates to multiple species of fish, including rainbow trout Oncorhynchus mykiss. In addition, improved genotyping methods have shown that some isolates previously classified as genomovar I, and used in challenge experiments, were in fact genomovar III. Our objective was to confirm previous results with respect to genomovar II virulence, and to determine the susceptibility of rainbow trout to other genomovars. The virulence of 8 genomovar I, 4 genomovar II, 3 genomovar II-B, and 5 genomovar III isolates originating from various sources was determined through 3 independent challenges in rainbow trout using an immersion challenge model. Mean cumulative percent mortality (CPM) of ~49% for genomovar I isolates, ~1% for genomovar II, ~5% for the II-B isolates, and ~7% for the III isolates was observed. The inability of genomovar II isolates to produce mortalities in rainbow trout was unanticipated based on previous studies, but may be due to a number of factors including rainbow trout source and water chemistry. The source of fish and/or the presence of sub-optimal environment may influence the susceptibility of rainbow trout to different F. columnare genomovars.

  17. 75 FR 70897 - Notice of Request for Extension of Approval of an Information Collection; South American Cactus...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-19

    ... Collection; South American Cactus Moth; Quarantine and Regulations AGENCY: Animal and Plant Health Inspection... moth. DATES: We will consider all comments that we receive on or before January 18, 2011. ADDRESSES... American cactus moth, contact Dr. Robyn Rose, Program Manager, Emergency and Domestic Programs, PPQ,...

  18. 77 FR 26000 - Cactus Energy LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Cactus Energy LLC; Supplemental Notice That Initial Market-Based Rate Filing...-referenced proceeding of Cactus Energy LLC's application for market-based rate authority, with...

  19. Revealing the elusive sex pheromone of the renowned cactus moth, Cactoblastis cactorum (Lepidoptera:Pyralidae): A tribute to Robert Heath

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The South American cactus moth, Cactoblastis cactorum (Berg.) (Lepidoptera: Pyralidae), became famous as a biocontrol agent during campaigns in Australia and South Africa to control exotic weedy Opuntia spp. During these campaigns, monitoring the impact and success of the cactus moth did not requir...

  20. The cactus webworm, Loxomorpha flavidissimalis (Grote, 1878) (Pyraloidea, Crambidae): its distribution and a potential pest in Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report Loxomorpha flavidissimalis, the cactus webworm, for the first time from Tamaulipas, Mexico, as an herbivore of the cultivated cactus, Opuntia ficus-indica. We observed larvae over a four year period (2010-2014) during the months of March to November and found young cladode losses attributa...

  1. Effects of ultrasound treatment in purple cactus pear (Opuntia ficus-indica) juice.

    PubMed

    Zafra-Rojas, Quinatzin Yadira; Cruz-Cansino, Nelly; Ramírez-Moreno, Esther; Delgado-Olivares, Luis; Villanueva-Sánchez, Javier; Alanís-García, Ernesto

    2013-09-01

    Cactus pear (Opuntia ficus-indica) fruit is a berry with a tasty pulp full of seeds that constitutes about 10-15% of the edible pulp. In Mexico, cactus pear is mainly consumed fresh, but also has the potential to be processed in other products such as juice. The objective of this study was to evaluate the effect of different ultrasound conditions at amplitude levels ranging (40% and 60% for 10, 15, 25 min; 80% for 3, 5, 8, 10, 15 and 25 min) on the characteristics of purple cactus pear juice. The evaluated parameters were related with the quality (stability, °Brix, pH), microbial growth, total phenolic compounds, ascorbic acid and antioxidant activity (ABTS, DPPH and % chelating activity) of purple cactus pear juices. The ultrasound treatment for time period of 15 and 25 min significantly reduced the microbial count in 15 and 25 min, without affecting the juice quality and its antioxidant properties. Juice treated at 80% of amplitude level showed an increased of antioxidant compounds. Our results demonstrated that sonication is a suitable technique for cactus pear processing. This technology allows the achievement of juice safety and quality standards without compromising the retention of antioxidant compounds.

  2. Phytochemicals, nutritionals and antioxidant properties of two prickly pear cactus cultivars (Opuntia ficus indica Mill.) growing in Taif, KSA.

    PubMed

    Abdel-Hameed, El-Sayed S; Nagaty, Mohamed A; Salman, Mahmood S; Bazaid, Salih A

    2014-10-01

    The antioxidant properties, some phytochemicals and nutritionals were characterized in two prickly pear cactus (Opuntia ficus indica Mill.) cultivars; red and yellow; growing in Taif, Kingdom of Saudi Arabia (KSA). The antioxidant properties of red cactus cultivar were higher than the yellow cactus cultivar. Linear correlation appeared between the antioxidant properties and total phenolics. All samples nearly have the same quantity of iron, copper, sodium and potassium. Some phenolic compounds were detected by HPLC-UV analysis. HPLC-RI analysis of all samples revealed the absence of sucrose and the presence of glucose and fructose. According to the above results, this study gave a good indication about the nutritional and pharmaceutical potential of the two cactus cultivars that must be widespread cultivated in arid and semiarid regions as KSA accompanying with establishment of industries beside the cactus farms that used all parts of plants.

  3. Soil compaction vulnerability at Organ Pipe Cactus National Monument, Arizona

    USGS Publications Warehouse

    Webb, Robert H.; Nussear, Kenneth E.; Carmichael, Shinji; Esque, Todd C.

    2014-01-01

    Compaction vulnerability of different types of soils by hikers and vehicles is poorly known, particularly for soils of arid and semiarid regions. Engineering analyses have long shown that poorly sorted soils (for example, sandy loams) compact to high densities, whereas well-sorted soils (for example, eolian sand) do not compact, and high gravel content may reduce compaction. Organ Pipe Cactus National Monument (ORPI) in southwestern Arizona, is affected greatly by illicit activities associated with the United States–Mexico border, and has many soils that resource managers consider to be highly vulnerable to compaction. Using geospatial soils data for ORPI, compaction vulnerability was estimated qualitatively based on the amount of gravel and the degree of sorting of sand and finer particles. To test this qualitative assessment, soil samples were collected from 48 sites across all soil map units, and undisturbed bulk densities were measured. A scoring system was used to create a vulnerability index for soils on the basis of particle-size sorting, soil properties derived from Proctor compaction analyses, and the field undisturbed bulk densities. The results of the laboratory analyses indicated that the qualitative assessments of soil compaction vulnerability underestimated the area of high vulnerability soils by 73 percent. The results showed that compaction vulnerability of desert soils, such as those at ORPI, can be quantified using laboratory tests and evaluated using geographic information system analyses, providing a management tool that managers potentially could use to inform decisions about activities that reduce this type of soil disruption in protected areas.

  4. Acoustic emissions correlated with hydration of Saguaro Cactus

    NASA Astrophysics Data System (ADS)

    Wardell, L. J.; Rowe, C. A.

    2013-12-01

    For some years it has been demonstrated that hardwood trees produce acoustic emissions during periods of drought, which arise from cavitation in the xylem as water is withdrawn. These emissions not only provide insights into the fluid transport behavior within these trees, but also the degree to which cavitation can proceed before inevitable tree mortality. Such studies can have significant impact on our understanding of forest die-off in the face of climate change. Plant mortality is not limited to woody trees, however, and it is not only the coniferous and deciduous forests whose response to climate and rainfall changes are important. In the desert Southwest we observe changes to survival rates of numerous species of flora. One of the most conspicuous of these plants is the iconic Saguaro Cactus (Carnegiea gigantean). These behemoths of the Sonoran Desert are very sensitive to small perturbations in their environment. Specifically, during the summer monsoon season when the cacti become well-hydrated, they can absorb hundreds of gallons of water within a very short time frame. We have obtained a juvenile saguaro on which we are conducting experiments to monitor acoustic emissions during hydration and dessication cycles. We will report on our observations obtained using piezoelectric ceramic accelerometers whose signals are digitized up to 44 Khz and recorded during hydration.

  5. Agglomerative percolation on the Bethe lattice and the triangular cactus

    NASA Astrophysics Data System (ADS)

    Chae, Huiseung; Yook, Soon-Hyung; Kim, Yup

    2013-08-01

    Agglomerative percolation (AP) on the Bethe lattice and the triangular cactus is studied to establish the exact mean-field theory for AP. Using the self-consistent simulation method based on the exact self-consistent equations, the order parameter P∞ and the average cluster size S are measured. From the measured P∞ and S, the critical exponents βk and γk for k = 2 and 3 are evaluated. Here, βk and γk are the critical exponents for P∞ and S when the growth of clusters spontaneously breaks the Zk symmetry of the k-partite graph. The obtained values are β2 = 1.79(3), γ2 = 0.88(1), β3 = 1.35(5) and γ3 = 0.94(2). By comparing these exponents with those for ordinary percolation (β∞ = 1 and γ∞ = 1), we also find β∞ < β3 < β2 and γ∞ > γ3 > γ2. These results quantitatively verify the conjecture that the AP model belongs to a new universality class if the Zk symmetry is broken spontaneously, and the new universality class depends on k.

  6. Acoustic emissions correlated with hydration of Saguaro Cactus

    NASA Astrophysics Data System (ADS)

    Wardell, L. J.; Rowe, C. A.

    2012-12-01

    For some years it has been demonstrated that hardwood trees produce acoustic emissions during periods of drought, which arise from cavitation in the xylem as water is withdrawn. These emissions not only provide insights into the fluid transport behavior within these trees, but also the degree to which cavitation can proceed before inevitable tree mortality. Such studies can have significant impact on our understanding of forest die-off in the face of climate change. Plant mortality is not limited to woody trees, however, and it is not only the coniferous and deciduous forests whose response to climate and rainfall changes are important. In the desert Southwest we observe changes to survival rates of numerous species of flora. One of the most conspicuous of these plants is the iconic Saguaro Cactus (Carnegiea gigantean). These behemoths of the Sonoran Desert are very sensitive to small perturbations in their environment. Specifically, during the summer monsoon season when the cacti become well-hydrated, they can absorb hundreds of gallons of water within a very short time frame. We have obtained a juvenile saguaro on which we are conducting experiments to monitor acoustic emissions during hydration and dessication cycles. We will report on our observations obtained using piezoelectric ceramic accelerometers whose signals are digitized up to 44 Khz and recorded during hydration.

  7. A multi-structural and multi-functional integrated fog collection system in cactus.

    PubMed

    Ju, Jie; Bai, Hao; Zheng, Yongmei; Zhao, Tianyi; Fang, Ruochen; Jiang, Lei

    2012-01-01

    Multiple biological structures have demonstrated fog collection abilities, such as beetle backs with bumps and spider silks with periodic spindle-knots and joints. Many Cactaceae species live in arid environments and are extremely drought-tolerant. Here we report that one of the survival systems of the cactus Opuntia microdasys lies in its efficient fog collection system. This unique system is composed of well-distributed clusters of conical spines and trichomes on the cactus stem; each spine contains three integrated parts that have different roles in the fog collection process according to their surface structural features. The gradient of the Laplace pressure, the gradient of the surface-free energy and multi-function integration endow the cactus with an efficient fog collection system. Investigations of the structure-function relationship in this system may help us to design novel materials and devices to collect water from fog with high efficiencies.

  8. Construction of two selectable markers for integrative/conjugative plasmids in Flavobacterium columnare

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Zou, Hong; Wang, Liangfa; Huang, Bei; Li, Nan; Wang, Guitang; Nie, Pin

    2012-03-01

    Flavobacterium columnare, the etiological agent of columnaris disease, is one of the most important and widespread bacterial pathogens of freshwater fish. In this study, we constructed two artificial selectable markers (chloramphenicol and spectinomycin resistance) for gene transfer in F. columnare. These two new artificial selectable markers, which were created by placing the chloramphenicol or spectinomycin resistance gene under the control of the native acs regulatory region of F. columnare, were functional in both F. columnare and Escherichia coli. The integrative/conjugative plasmids constructed by using these markers were introduced into F. columnare G4 via electroporation or conjugation. The integrated plasmid DNA was confirmed by Southern blotting and PCR analysis. These two markers can be employed in future investigations into gene deletion and the pathogenicity of virulence factors in F. columnare.

  9. Relationships among mercury, selenium, and neurochemical parameters in common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus).

    PubMed

    Scheuhammer, A M; Basu, N; Burgess, N M; Elliott, J E; Campbell, G D; Wayland, M; Champoux, L; Rodrigue, J

    2008-02-01

    Fish-eating birds can be exposed to levels of dietary methylmercury (MeHg) known or suspected to adversely affect normal behavior and reproduction, but little is known regarding Hg's subtle effects on the avian brain. In the current study, we explored relationships among Hg, Se, and neurochemical receptors and enzymes in two fish-eating birds--common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus). In liver, both species demonstrated a wide range of total Hg (THg) concentrations, substantial demethylation of MeHg, and a co-accumulation of Hg and Se. In liver, there were molar excesses of Se over Hg up to about 50-60 microg/g THg, above which there was an approximate 1:1 molar ratio of Hg:Se in both species. However, in brain, bald eagles displayed a greater apparent ability to demethylate MeHg than common loons. There were molar excesses of Se over Hg in brains of bald eagles across the full range of THg concentrations, whereas common loons often had extreme molar excesses of Hg in their brains, with a higher proportion of THg remaining as MeHg compared with eagles. There were significant positive correlations between brain THg and muscarinic cholinergic receptor concentrations in both species studied; whereas significant negative correlations were observed between N-methyl-D-aspartic acid (NMDA) receptor levels and brain Hg concentration. There were no significant correlations between brain Se and neurochemical receptors or enzymes (cholinesterase and monoamine oxidase) in either species. Our findings suggest that there are significant differences between common loons and bald eagles with respect to cerebral metabolism and toxicodynamics of MeHg and Se. These interspecies differences may influence relative susceptibility to MeHg toxicity; however, neurochemical responses to Hg in both species were similar.

  10. Hepatic polybrominated diphenyl ether (PBDE) levels in Wisconsin river otters (Lontra canadensis) and Michigan bald eagles (Haliaeetus leucocephalus)

    PubMed Central

    Dornbos, Peter; Chernyak, Sergei; Rutkiewicz, Jennifer; Cooley, Thomas; Strom, Sean; Batterman, Stuart; Basu, Niladri

    2015-01-01

    Polybrominated diphenyl ethers (PBDEs) are persistent and toxic flame-retardant chemicals widespread in the Great Lakes ecosystem. These chemicals are now being regulated and phased-out of the region; therefore it remains important to understand the extent of contamination in order to track the efficacy of recent actions. Here, Σ4PBDE congeners (PBDE-47, 99, 100, 153;wetweight basis unless indicated)were determined in liver tissues from Wisconsin river otters (Lontra canadensis; n = 35; 2009–2010) and Michigan bald eagles (Haliaeetus leucocephalus; n = 33; 2009–2011). In otters, Σ4PBDE ranged from0.5 to 72.9 ng/g, with a mean (±SD) and median (25th–75th percentile inter-quartile range) of 16.3 ± 16.4 ng/g and 11.3 (5.6–18.9) ng/g, respectively. The mean lipid-adjusted Σ4PBDE was 1377 ± 1485 ng/g. In eagles, Σ4PBDE ranged from 0 to 1,538.8 ng/g, with a mean and median of 74.3 ± 266.7 ng/g and 21.2 (5.7–28.9) ng/g, respectively. The mean lipid-adjusted Σ4PBDE was 5274.5 ± 19,896.1 ng/g. In both species, PBDE-47 accounted for >50% of the Σ4PBDE, followed by PBDE-99 and PBDE-100 (each ~17–19% of the total). The PBDE levels reported here in otters are similar to mammalian wildlife elsewhere, though the levels in eagles are among the highest worldwide across studied birds. The findings indicate that apex Great Lakes wildlife remain exposed to appreciable levels of PBDEs and more work is needed to understand whether such exposures are associated with adverse health outcomes. PMID:25745277

  11. Brominated flame retardants and halogenated phenolic compounds in North American west coast bald eaglet (Haliaeetus leucocephalus) plasma.

    PubMed

    McKinney, Melissa A; Cesh, Lillian S; Elliott, John E; Williams, Tony D; Garcelon, David K; Letcher, Robert J

    2006-10-15

    We report on the identity, characterization, and spatial trends of several brominated flame retardants and hydroxylated (OH-) and methoxylated (MeO-) organohalogen contaminants in bald eagle (Haliaeetus leucocephalus) nestling plasma collected from sites along the west coast of North America. Samples were from four southwestern British Columbia (BC) locations, a reference site in northern BC (Fort St. James; FSJ), and from Santa Catalina Island, CA (SCI), an area of high DDT and PCB contamination. Mean concentrations of sigma polybrominated diphenyl ether (sigma PBDE (8 congeners monitored); 1.78-8.49 ng/g), sigma OH-polychlorinated biphenyl (sigma OH-PCB (30 congeners monitored); 0.44-0.87 ng/g), and sigma OH-PBDE (14 congeners monitored; 0.31-0.92 ng/g) were similar in eaglets from southwestern BC yet lower than for SCl and significantly higher than for FSJ. Dominant PBDE congeners were BDE47, BDE99, and BDE100, but SCl eaglets also contained low levels of higher brominated congeners. 4-OH-CB187 and 4'-OH-CB202 accounted for 65-100% of sigma OH-PCB in all BC eaglets, with 4'-OH-CB202 as well as 3'-OH-CB138 and 4-OH-CB146 dominating in SCl eaglets. Ostensibly of biogenic origin, 6'-OH-BDE49 and 6-OH-BDE47 were found in BC nestlings. Only 4'-OH-BDE49 (2.10 ng/g) was found in SCl eaglets. MeO-PBDEs and total hexabromocyclododecane (HBCD) were not found in any birds, but the polybrominated biphenyl BB101 was detected in southwestern BC samples. This study demonstrates that west coast North American bald eagles contain previously unreported organohalogens, which have the potential to impact the health and survival of these raptors.

  12. Biological effects of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in bald eagle (Haliaeetus leucocephalus) chicks

    SciTech Connect

    Elliott, J.E. |; Norstrom, R.J.; Lorenzen, A.; Kennedy, S.W.; Hart, L.E.; Bellward, G.D.; Cheng, K.M.; Philibert, H.; Stegeman, J.J.

    1996-05-01

    During the 1992 breeding season, eggs of bald eagles (Haliaeetus leucocephalus) were collected within a gradient of exposure to chlorinated hydrocarbon pollutants on the southern coast of British Columbia. Twenty-five eggs were placed in a laboratory incubator, of which 18 hatched; chicks were sacrificed within 24 h. Hatching success was not significantly different between eggs taken from pulp mill sites and reference sites. A hepatic cytochrome P4501A (CYP1A) cross-reactive protein was induced nearly sixfold in chicks from near a pulp mill at Powell River compared to those from a reference site. Hepatic ethoxyresorufin-O-deethylase (EROD) and benzyloxyresorufin O-dealkylase (BROD) activities were also significantly elevated in chicks from nests located near pulp mills compared to reference sites. A hepatic CYP2B cross-reactive protein was threefold higher in chicks from pulp mill versus reference sites, but the difference was not significant. Residual yolk sacs of eggs collected near pulp mill sites contained greater concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) compared to reference areas. No significant differences in concentrations of polychlorinated biphenyls (PCBs), non-ortho congeners, and organochlorine pesticides occurred among sites. Regressions showed that the hepatic CYP1A cross-reactive protein and EROD and BROD activities were positively correlated with 2,3,7,8-TCDD, 2,3,7,8-TCDF, and toxic equivalents (TEQs{sub WHO}--World Health Organization toxic equivalence factors) in yolk sacs. No significant concentration-related effects were found for morphological, physiological, or histological parameters, such as chick growth, edema, or density of thymic lymphocytes. Using hepatic CYP1A induction as a biomarker, a no-observed-effect-level of 100 ng/kg and a lowest-observed-effect-level of 210 ng/kg TEQs{sub WHO} on a whole egg (wet weight basis) are suggested for bald eagle chicks.

  13. Relationships among mercury, selenium, and neurochemical parameters in common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus).

    PubMed

    Scheuhammer, A M; Basu, N; Burgess, N M; Elliott, J E; Campbell, G D; Wayland, M; Champoux, L; Rodrigue, J

    2008-02-01

    Fish-eating birds can be exposed to levels of dietary methylmercury (MeHg) known or suspected to adversely affect normal behavior and reproduction, but little is known regarding Hg's subtle effects on the avian brain. In the current study, we explored relationships among Hg, Se, and neurochemical receptors and enzymes in two fish-eating birds--common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus). In liver, both species demonstrated a wide range of total Hg (THg) concentrations, substantial demethylation of MeHg, and a co-accumulation of Hg and Se. In liver, there were molar excesses of Se over Hg up to about 50-60 microg/g THg, above which there was an approximate 1:1 molar ratio of Hg:Se in both species. However, in brain, bald eagles displayed a greater apparent ability to demethylate MeHg than common loons. There were molar excesses of Se over Hg in brains of bald eagles across the full range of THg concentrations, whereas common loons often had extreme molar excesses of Hg in their brains, with a higher proportion of THg remaining as MeHg compared with eagles. There were significant positive correlations between brain THg and muscarinic cholinergic receptor concentrations in both species studied; whereas significant negative correlations were observed between N-methyl-D-aspartic acid (NMDA) receptor levels and brain Hg concentration. There were no significant correlations between brain Se and neurochemical receptors or enzymes (cholinesterase and monoamine oxidase) in either species. Our findings suggest that there are significant differences between common loons and bald eagles with respect to cerebral metabolism and toxicodynamics of MeHg and Se. These interspecies differences may influence relative susceptibility to MeHg toxicity; however, neurochemical responses to Hg in both species were similar. PMID:17899374

  14. Use of a locking compression plate as an external fixator for repair of a tarsometatarsal fracture in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Montgomery, Ronald D; Crandall, Elizabeth; Bellah, Jamie R

    2011-06-01

    We describe the successful treatment of a tarsometatarsal fracture in a mature bald eagle (Haliaeetus leucocephalus) using a locking compression plate as an external fixator. The anatomy of the area (inelastic dermis and minimal subcutaneous space) and the high forces placed on a fracture at that site necessitated a unique approach to fixation. The unconventional use of a locking compression plate as an external fixator was minimally invasive, well tolerated by the eagle, and provided adequate stability in opposing fracture forces. This technique may serve as a method of fixation for tarsometatarsal fractures in other large avian species.

  15. Use of a locking compression plate as an external fixator for repair of a tarsometatarsal fracture in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Montgomery, Ronald D; Crandall, Elizabeth; Bellah, Jamie R

    2011-06-01

    We describe the successful treatment of a tarsometatarsal fracture in a mature bald eagle (Haliaeetus leucocephalus) using a locking compression plate as an external fixator. The anatomy of the area (inelastic dermis and minimal subcutaneous space) and the high forces placed on a fracture at that site necessitated a unique approach to fixation. The unconventional use of a locking compression plate as an external fixator was minimally invasive, well tolerated by the eagle, and provided adequate stability in opposing fracture forces. This technique may serve as a method of fixation for tarsometatarsal fractures in other large avian species. PMID:21877449

  16. Cortisol directly impacts Flavobacterium columnare in vitro growth characteristics.

    PubMed

    Declercq, Annelies Maria; Aerts, Johan; Ampe, Bart; Haesebrouck, Freddy; De Saeger, Sarah; Decostere, Annemie

    2016-01-01

    Teleost fish faced with stressful stimuli launch an endocrine stress response through activation of the hypothalamic-pituitary-interrenal axis to release glucocorticoids, in particular cortisol, into the blood. For the majority of bacterial fish pathogens, stress is considered a key factor in disease outbreaks. Based upon studies in mammals, there is considerable evidence to suggest that, besides impairing the immune system, cortisol can have a direct effect on bacterial cells. Hitherto, this intriguing field of microbial endocrinology has remained largely unexplored in aquatic diseases. The present study investigated in vitro the impact of cortisol on phenotypic traits of the fresh water fish pathogen Flavobacterium columnare. Colonies obtained from the highly virulent (HV) isolates resulted in significantly larger and more spreading colonies compared to those from the low virulent (LV) isolates. High cortisol doses added displayed a direct effect on the bacterial cells and induced a significant decrease in colony size. An additional intriguing finding was the inverse relationship between cortisol concentrations added to the broth and the spreading character of colonies retrieved, with higher cortisol doses resulting in less rhizoid to rough and even smooth colony formation (the latter only in the LV trout isolate), suggesting a dose-response effect. The loss of the rhizoid appearance of the F. columnare colonies upon administration of cortisol, and hence the loss of motility, might indicate a phenotypic change to the biofilm state. These findings form the basis for further research on the impact of glucocorticoids on other virulence factors and biofilm formation of F. columnare. PMID:27530746

  17. Unravelling columnar joints temperatures: a thermo-mechanical experimental approach

    NASA Astrophysics Data System (ADS)

    Lavallée, Yan; Lamur, Anthony; Iddon, Fiona E.; Kendrick, Jackie E.; Hornby, Adrian J.; Eggertson, Gudjon H.; Von Aulock, Felix W.; Wadsworth, Fabian B.

    2016-04-01

    Columnar joints are a widespread, spectacular volcanic phenomenon representing a complex cracking pattern induced by contraction of the lava upon cooling. The hexagonal geometry results from the complex interaction between heat dissipation, contraction and tensile fracturing of the material. While the formation mechanism is nowadays fairly well constrained, very little is known on the temperature at which these features form. Here, we present the results of a novel type of thermo-mechanical experiment, in which the ends of 16 mm rods of basalt were locked into position during cooling at different rates. We monitored the stress build-up and temperature within the samples in order to constrain the temperature of columnar jointing. Our experiments were applied to basaltic rocks sampled on a lava flow at the base of Eyjafjallajoküll volcano in Iceland. Results demonstrate that thermal contraction upon cooling triggers microscopic fracturing (at ~820 °C) that quickly evolves into localised macroscopic fracturing at 750-780 °C. Striaes observed along fracture planes can hence be interpreted as the reflection of this two-stage fracture propagation dynamics. We emphasize that columnar jointing occurs well within the solid state of volcanic rocks, not in a molten regime. These results are supported by complementary analysis of the expansion coefficient of these lavas as well as strain-to-failure acquired during Brazilian tensile tests. The nonlinearity of the coefficient of expansion has important implications for the development of a permeable network. At higher temperatures, micro-fracturing is caused by a quasi-linear coefficient of expansion, leading to a small increase in permeability. As cooling occurs, the coefficient of expansion drops increasingly rapidly, leading to an increasingly faster developing permeable network, which is controlled in-part by the scale of the columns that influences crack aperture opening. Our findings hence have implications in volcanic

  18. A discotic disguised as a smectic: A hybrid columnar bragg glass

    PubMed

    Saunders; Radzihovsky; Toner

    2000-11-13

    We show that discotics, lying deep in the columnar phase, can exhibit an x-ray scattering pattern which mimics that of a somewhat unusual smectic liquid crystal. This exotic, new glassy phase of columnar liquid crystals, which we call a "hybrid columnar Bragg glass," can be achieved by confining a columnar liquid crystal in an anisotropic random environment of, e.g., strained aerogel. Long-ranged orientational order in this phase makes single-domain x-ray scattering possible, from which a wealth of information could be extracted. We give detailed quantitative predictions for the scattering pattern in addition to exponents characterizing anomalous elasticity of the system. PMID:11060625

  19. Ultraviolet spectrophotometer for measuring columnar atmospheric ozone from aircraft.

    PubMed

    Hanser, F A; Sellers, B; Briehl, D C

    1978-05-15

    An ultraviolet spectrophotometer (UVS) to measure downward solar fluxes from an aircraft or other high altitude platform is described. The UVS uses an ultraviolet diffuser to obtain large angular response with no aiming requirement, a twelve-position filter wheel with narrow (2-nm) and broad (20-nm) bandpass filters, and an ultraviolet photodiode. The columnar atmospheric ozone above the UVS (aircraft) is calculated from the ratios of the measured ultraviolet fluxes. Comparison with some Dobson station measurements gives agreement to 2%. Some UVS measured ozone profiles over the Pacific Ocean for November 1976 are shown to illustrate the instrument's performance.

  20. Architecture of Columnar Nacre, and Implications for Its Formation Mechanism

    NASA Astrophysics Data System (ADS)

    Metzler, Rebecca A.; Abrecht, Mike; Olabisi, Ronke M.; Ariosa, Daniel; Johnson, Christopher J.; Frazer, Bradley H.; Coppersmith, Susan N.; Gilbert, P. U. P. A.

    2007-06-01

    We analyze the structure of Haliotis rufescens nacre, or mother-of-pearl, using synchrotron spectromicroscopy and x-ray absorption near-edge structure spectroscopy. We observe imaging contrast between adjacent individual nacre tablets, arising because different tablets have different crystal orientations with respect to the radiation’s polarization vector. Comparing previous data and our new data with models for columnar nacre growth, we find the data are most consistent with a model in which nacre tablets are nucleated by randomly distributed sites in the organic matrix layers.

  1. Architecture of columnar nacre, and implications for its formation mechanism.

    PubMed

    Metzler, Rebecca A; Abrecht, Mike; Olabisi, Ronke M; Ariosa, Daniel; Johnson, Christopher J; Frazer, Bradley H; Coppersmith, Susan N; Gilbert, P U P A

    2007-06-29

    We analyze the structure of Haliotis rufescens nacre, or mother-of-pearl, using synchrotron spectromicroscopy and x-ray absorption near-edge structure spectroscopy. We observe imaging contrast between adjacent individual nacre tablets, arising because different tablets have different crystal orientations with respect to the radiation's polarization vector. Comparing previous data and our new data with models for columnar nacre growth, we find the data are most consistent with a model in which nacre tablets are nucleated by randomly distributed sites in the organic matrix layers.

  2. Periodically patterned columnar thin films as blazed diffraction gratings

    SciTech Connect

    Dutta, Jhuma; Anantha Ramakrishna, S.; Lakhtakia, Akhlesh

    2013-04-22

    Periodically patterned columnar thin films (PP-CTFs) were made by evaporating CaF{sub 2} and directing the vapor flux obliquely towards lithographically fabricated micrometer/sub-micrometer gratings. The growth of the PP-CTFs was controlled by the deposition rate to form prismatic air cavities within them. These PP-CTFs function like blazed diffraction gratings with asymmetric diffraction patterns and diffraction efficiencies up to 80% in transmission at ultraviolet-visible wavelengths. Diffraction theory adequately establishes that the blazing action arises due to the prismatic cavities and explains the measured diffraction efficiencies.

  3. Architecture of Columnar Nacre, and Implications for Its Formation Mechanism

    SciTech Connect

    Metzler, Rebecca A.; Olabisi, Ronke M.; Coppersmith, Susan N.; Gilbert, P. U. P. A.; Abrecht, Mike; Frazer, Bradley H.; Ariosa, Daniel; Johnson, Christopher J.

    2007-06-29

    We analyze the structure of Haliotis rufescens nacre, or mother-of-pearl, using synchrotron spectromicroscopy and x-ray absorption near-edge structure spectroscopy. We observe imaging contrast between adjacent individual nacre tablets, arising because different tablets have different crystal orientations with respect to the radiation's polarization vector. Comparing previous data and our new data with models for columnar nacre growth, we find the data are most consistent with a model in which nacre tablets are nucleated by randomly distributed sites in the organic matrix layers.

  4. Genome organization and gene expression of saguaro cactus carmovirus.

    PubMed

    Weng, Z; Xiong, Z

    1997-03-01

    The complete sequence of the single-stranded, (+)-sense RNA genome of saguaro cactus carmovirus (SCV) has been determined. The 3879 nucleotide genome contains five open reading frames (ORFs). The 5'-proximal ORF encodes a 26 kDa protein (p26) and terminates with an amber codon which is readthrough into an in-frame p57 ORF to generate an 86 kDa fusion protein (p86). Two small, centrally located ORFs encode a 6 kDa protein (p6) and a 9 kDa protein (p9), respectively. The 3'-proximal ORF encodes a 37 kDa (p37) capsid protein (CP). Analysis of the nucleotide and predicted amino acid sequences supports the classification of SCV in the genus Carmovirus in the family Tombusviridae. All predicted SCV proteins are expressed in an in vitro translation system. SCV p26 and the readthrough fusion protein p86 are synthesized from the genomic RNA while p6, p9 and p37 CP ORFs at the 3' half of the genome are expressed from two subgenomic (sg) RNAs. The 5' termini of both sg RNAs have been mapped. The large 1614 nucleotide sg RNA contains the p6 and p9 ORFs as the first and the second ORFs respectively from its 5' end. It directs the synthesis of abundant p6 but a small amount of p9. While a synthetic transcript with the p9 ORF at the 5' end is a more efficient messenger for p9, no corresponding sg RNA has been identified in vivo. The smaller 1396 nucleotide sg RNA contains only the p37 ORF and directs the synthesis of SCV CP. PMID:9049400

  5. Nocardioides opuntiae sp. nov., isolated from soil of a cactus.

    PubMed

    Lee, Soon Dong; Seong, Chi Nam

    2014-06-01

    A novel high G+C actinobacterium, designated strain OS1-21(T), was isolated from the rhizosphere soil of a cactus (Opuntia fiscus-indica var. sanboten) and the taxonomic status was investigated using a polyphasic approach. Cells of strain OS1-21(T) were aerobic, Gram-stain-positive, non-endospore-forming, non-motile rods; colonies of the cells were circular, translucent, smooth and moderate yellow in colour. LL-Diaminopimelic acid was the diagnostic diamino acid in cell-wall peptidoglycan. The predominant menaquinone was MK-8(H4). The major fatty acids were iso-C(16 : 0), iso-C(16 : 0) 2-OH, 10-methyl C(17 : 0), 10-methyl C(18 : 0) and C(17 : 1)cis9. The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two unknown phospholipids. The DNA G+C content was 73.7 mol%. Based on 16S rRNA gene sequence analysis, the closest phylogenetic neighbours were Nocardioides panacihumi Gsoil 616(T) (98.7% sequence similarity) and Nocardioides terrae VA15(T) (97.8%), followed by Nocardioides marinus CL-DD14(T) (97.1%). DNA-DNA relatedness values of strain OS1-21(T) with the type strains of the closest phylogenetic neighbours were low (<16.0%). Combined data of polyphasic taxonomic analyses revealed that the organism could be assigned to a novel species of the genus Nocardioides, for which the name Nocardioides opuntiae sp. nov. is proposed. The type strain is OS1-21(T) ( = KCTC 19804(T) = NBRC 107915(T)).

  6. Validation of simulated point response of columnar phosphor screens

    NASA Astrophysics Data System (ADS)

    Badano, Aldo; Kyprianou, Iacovos S.; Tang, Katherine H.; Saha, Anindita

    2007-03-01

    Typical methods to measure the resolution properties of x-ray detectors use slit or edge devices. However, complete models of imaging systems for system optimization require knowledge of the point-response function of the detector. In this paper, we report on the experimental methods developed for the validation of the point-response function of an indirect columnar CsI:Tl detector predicted by Monte Carlo using mantis. We describe simulation results that replicate experimental resolution measurements using edge and pinhole devices. The experimental setup consists of a high-resolution CCD camera with a 1-to-1fiber optic faceplate that allows measurements for different scintillation screens. The results of these experiments and simulations constitute a resource for the development and validation of the columnar models of phosphor screens proposed as part of previous work with mantis. We compare experimental high-resolution pinhole responses of two different CsI(Tl) screens to predictions from mantis. The simulated response matches reasonably well the measurements at normal and off-normal x-ray incidence angle when a realistic pinhole is used in the simulation geometry. Our results will be combined with results on Swank factors determined from Monte Carlo pulse-height spectra to provide a comprehensive validation of the phosphor models, therefore allowing their use for in silico system optimization.

  7. Trail marking by the larvae of the cactus moth, Cactoblastis cactorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cactoblastis cactorum (Lepidoptera: Pyralidae) spends most of its larval life feeding within the cladodes of Opuntia cactuses, but the gregarious caterpillars begin their life outside the plant, and in the later instars make intermittent excursions over plant surfaces to access new cladodes and to t...

  8. Phylogeographic analysis of Harrisia cactus mealybug, Hypogeococcus pungens (Hemiptera: Pseudoccidae) populations: work in progress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harrisia cactus mealybug (HCM), Hypogeococcus pungens (Hemiptera: Pseudoccidae) Granara de Willink (1981) is infesting and killing cacti in the southern coast of Puerto Rico, covering an area of about 1,400 km2. The 13 species of cacti occurring in Puerto Rico are threatened by this new pest; three...

  9. [Effects of cactus, alove veral, momorcica charantia on reducing the blood glucose of diabetic mice].

    PubMed

    Lin, X; Shen, X; Long, Z; Yang, Q

    2001-07-01

    The effects of cactus, alove veral and momorcica charantia on reducing the blood glucose level of mice were observed. The diabetic model with no symptom in mice was established by injection of streptozotocin(STZ) 80 mg/kg BW into abdominal cavity for 11 days. The diabetic mice were randomly divided into 8 groups: STZ diabetic model, diet A, diet B, cactus, alove veral, momordica charantia and glyburide groups. Cactus (60 g/kg BW), alove veral (60 g/kg BW), and momordica charantia (30 g/kg BW) were administrated orally each day to the diabetic mice for another 21 days. Serum glucose of mice fasting for 12 hours and 2 hours after meal was determined with the method of glucose-oxidase at the 21th day of the experiment. The results showed that serum glucose levels of diabetic mice were significantly higher than the normal control group (P < 0.01). After giving diet A, cactus, alove veral and momorcica charantia juice for 21 days, the serum glucose concentration of these diabetic mice were significantly lower than STZ diabetic model group (P < 0.01) but still higher than the normal control group.

  10. Characterization of a male reproductive transcriptome for Peromyscus eremicus (Cactus mouse)

    PubMed Central

    2016-01-01

    Rodents of the genus Peromyscus have become increasingly utilized models for investigations into adaptive biology. This genus is particularly powerful for research linking genetics with adaptive physiology or behaviors, and recent research has capitalized on the unique opportunities afforded by the ecological diversity of these rodents. Well characterized genomic and transcriptomic data is intrinsic to explorations of the genetic architecture responsible for ecological adaptations. Therefore, this study characterizes the transcriptome of three male reproductive tissues (testes, epididymis and vas deferens) of Peromyscus eremicus (Cactus mouse), a desert specialist. The transcriptome assembly process was optimized in order to produce a high quality and substantially complete annotated transcriptome. This composite transcriptome was generated to characterize the expressed transcripts in the male reproductive tract of P. eremicus, which will serve as a crucial resource for future research investigating our hypothesis that the male Cactus mouse possesses an adaptive reproductive phenotype to mitigate water-loss from ejaculate. This study reports genes under positive selection in the male Cactus mouse reproductive transcriptome relative to transcriptomes from Peromyscus maniculatus (deer mouse) and Mus musculus. Thus, this study expands upon existing genetic research in this species, and we provide a high quality transcriptome to enable further explorations of our proposed hypothesis for male Cactus mouse reproductive adaptations to minimize seminal fluid loss. PMID:27812417

  11. Phytobezoar from the stem ("quiote") of the cactus Agave americana: report of case.

    PubMed

    Villarreal, R; Martinez, O; Berumen, U

    1985-11-01

    Agave americana is a cactus growing abundantly in Mexico. Its cooked stem ("quiote") yields by mastication a sweet juice which is swallowed, while the fibers ("bagazo") are spit out. That is the way Mexicans are taught to chew quiote since their early childhood, and it accounts for the rarity of bezoars from this origin. One of such cases is reported herein.

  12. Epizootic vacuolar myelinopathy of the central nervous system of bald eagles (Haliaeetus leucocephalus) and American coots (Fulica americana).

    PubMed

    Thomas, N J; Meteyer, C U; Sileo, L

    1998-11-01

    Unprecedented mortality occurred in bald eagles (Haliaeetus leucocephalus) at DeGray Lake, Arkansas, during the winters of 1994-1995 and 1996-1997. The first eagles were found dead during November, soon after arrival from fall migration, and deaths continued into January during both episodes. In total, 29 eagles died at or near DeGray Lake in the winter of 1994-1995 and 26 died in the winter of 1996-1997; no eagle mortality was noted during the same months of the intervening winter or in the earlier history of the lake. During the mortality events, sick eagles were observed overflying perches or colliding with rock walls. Signs of incoordination and limb paresis were also observed in American coots (Fulica americana) during the episodes of eagle mortality, but mortality in coots was minimal. No consistent abnormalities were seen on gross necropsy of either species. No microscopic findings in organs other than the central nervous system (CNS) could explain the cause of death. By light microscopy, all 26 eagles examined and 62/77 (81%) coots had striking, diffuse, spongy degeneration of the white matter of the CNS. Vacuolation occurred in all myelinated CNS tissue, including the cerebellar folia and medulla oblongata, but was most prominent in the optic tectum. In the spinal cord, vacuoles were concentrated near the gray matter, and occasional swollen axons were seen. Vacuoles were uniformly present in optic nerves but were not evident in the retina or peripheral or autonomic nerves. Cellular inflammatory response to the lesion was distinctly lacking. Vacuoles were 8-50 microns in diameter and occurred individually, in clusters, or in rows. In sections stained by luxol fast blue/periodic acid-Schiff stain, the vacuoles were delimited and transected by myelin strands. Transmission electron microscopy revealed intramyelinic vacuoles formed in the myelin sheaths by splitting of one or more myelin lamellae at the intraperiodic line. This lesion is characteristic of

  13. Epizootic vacuolar myelinopathy of the central nervous system of bald eagles (Haliaeetus leucocephalus) and American coots (Fulica americana)

    USGS Publications Warehouse

    Thomas, N.J.; Meteyer, C.U.; Sileo, L.

    1998-01-01

    Unprecedented mortality occurred in bald eagles (Haliaeetus leucocephalus) at DeGray Lake, Arkansas, during the winters of 1994-1995 and 1996-1997. The first eagles were found dead during November, soon after arrival from fall migration, and deaths continued into January during both episodes. In total, 29 eagles died at or near DeGray Lake in the winter of 1994-1995 and 26 died in the winter of 1996-1997; no eagle mortality was noted during the same months of the intervening winter or in the earlier history of the lake. During the mortality events, sick eagles were observed overflying perches or colliding with rock walls. Signs of incoordination and limb paresis were also observed in American coots (Fulica americana) during the episodes of eagle mortality, but mortality in coots was minimal. No consistent abnormalities were seen on gross necropsy of either species. No microscopic findings in organs other than the central nervous system (CNS) could explain the cause of death. By light microscopy, all 26 eagles examined and 62/77 (81%) coots had striking, diffuse, spongy degeneration of the white matter of the CNS. Vacuolation occurred in all myelinated CNS tissue, including the cerebellar folia and medulla oblongata, but was most prominent in the optic tectum. In the spinal cord, vacuoles were concentrated near the gray matter, and occasional swollen axons were seen. Vacuoles were uniformly present in optic nerves but were not evident in the retina or peripheral or autonomic nerves. Cellular inflammatory response to the lesion was distinctly lacking. Vacuoles were 8-50 microns in diameter and occurred individually, in clusters, or in rows. In sections stained by luxol fast blue/periodic acid-Schiff stain, the vacuoles were delimited and transected by myelin strands. Transmission electron microscopy revealed intramyelinic vacuoles formed in the myelin sheaths by splitting of one or more myelin lamellae at the intraperiodic line. This lesion is characteristic of

  14. Chemotactic factors of Flavobacterium columnare to skin mucus of healthy channel catfish (Ictalurus punctatus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To gain insight into chemotactic factors involved in chemotaxis, we exposed a virulent strain of Flavobacterium columnare to various treatments followed by analysis of its chemotactic activity. The chemotactic activity of F. columnare was significantly (p < 0.05) inhibited when cells were pretreated...

  15. Chemotactic factors of Flavobacterium columnare to skin mucus of healthy channel catfish (Ictalurus punctatus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To gain insight into chemotactic factors involved in chemotaxis, we exposed a virulent strain of Flavobacterium columnare to various treatments followed by analysis of its chemotactic activity. Chemotactic activity of F. columnare was significantly (p < 0.05) inhibited when cells were pretreated by ...

  16. Complete Genome Sequence of the Fish Pathogen Flavobacterium columnare Strain C#2.

    PubMed

    Bartelme, Ryan P; Newton, Ryan J; Zhu, Yongtao; Li, Nan; LaFrentz, Benjamin R; McBride, Mark J

    2016-01-01

    Flavobacterium columnare is a Gram-negative bacterial pathogen that causes columnaris disease of freshwater fish. Flavobacterium columnare strain C#2 was isolated from a diseased warm-water fish and is typed as genomovar II. The genome consists of a single 3.33-Mb circular chromosome with 2,689 predicted coding genes. PMID:27340080

  17. Basal polarization of the mucosal compartment in Flavobacterium columnare susceptible and resistant channel catfish Ictalurus punctatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The freshwater bacterial pathogen, Flavobacterium columnare, infects a variety of ornamental and farmed fish species worldwide through mucosal attachment points on the gill and skin. While previous studies have demonstrated a chemotactic response of F. columnare to fish mucus, little is known about ...

  18. Complete Genome Sequence of the Fish Pathogen Flavobacterium columnare Pf1

    PubMed Central

    Zhang, Yulei

    2016-01-01

    Flavobacterium columnare is the etiologic agent of columnaris disease, a devastating fish disease prevailing in worldwide aquaculture industry. Here, we describe the complete genome of F. columnare strain Pf1, a highly virulent strain isolated from yellow catfish (Pelteobagrus fulvidraco) in China. PMID:27587818

  19. Complete genome sequence of the fish pathogen Flavobacterium columnare strain C#2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is a Gram-negative bacterial pathogen that causes columnaris disease of freshwater fish. Flavobacterium columnare strain C#2 was isolated from a diseased warm water fish and is typed as genomovar II. The genome consists of a single 3.33 Mb circular chromosome with 2,689 pred...

  20. Isolation and characterization of Flavobacterium columnare strains infecting fishes inhabiting the Laurentian Great Lakes basin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare, the etiological agent of columnaris disease, causes significant losses in fish worldwide. In this study, F. columnare infection prevalence was assessed in representative Great Lakes fish species. Over 2,000 wild, feral, and hatchery-propagated salmonids, percids, centrarc...

  1. Composition of Extracellular Polymeric Substances (EPS) produced by Flavobacterium columnare isolated from tropical fish in Brazil.

    PubMed

    de Alexandre Sebastião, Fernanda; Pilarski, Fabiana; Lemos, Manoel Victor Franco

    2013-01-01

    Thirty nine isolates of Flavobacterium columnare from Brazilian fish farms had their carbohydrate composition of EPS evaluated by high efficiency liquid chromatography, using the phenol-sulfuric acid method of EPS. The occurrence of capsules on F. columnare cells was not directly related to biofilm formation, and the predominant monosaccharide is glucose.

  2. Genome sequence of the fish pathogen Flavobacterium columnare genomovar II strain 94-081

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Channel catfish is one of the most important commodities in Mississippi and the largest aquaculture industry in the United States. Columnaris disease, caused by Flavobacterium columnare, affects many commercially important freshwater fish species. F. columnare strain 94-081 was isolated from disease...

  3. Optimized reverse primer for 16S-RFLP analysis and genomovar assignment of Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is the causative agent of columnaris disease which severely impacts channel catfish production in the USA and has emerged as an important pathogen in the US rainbow trout industry. Our laboratory previously standardized a genetic typing system for F. columnare in which a por...

  4. Complete Genome Sequence of the Fish Pathogen Flavobacterium columnare Pf1.

    PubMed

    Zhang, Yulei; Nie, Pin; Lin, Li

    2016-01-01

    Flavobacterium columnare is the etiologic agent of columnaris disease, a devastating fish disease prevailing in worldwide aquaculture industry. Here, we describe the complete genome of F. columnare strain Pf1, a highly virulent strain isolated from yellow catfish (Pelteobagrus fulvidraco) in China. PMID:27587818

  5. Star Photometry for the Characterization of Columnar Aerosol Properties

    NASA Astrophysics Data System (ADS)

    Perez-Ramirez, D.; Lyamani, H.; Olmo Reyes, F. J.; Alados-Arboledas, L.; Whiteman, D. N.; Aceituno, J.

    2015-12-01

    Knowledge of columnar aerosol particles at nighttime is essential to completely understand aerosol dynamics and so will largely improve aerosol models. However, the current knowledge columnar nighttime aerosol is poor due to the lack of continuous measurements partly associated with previous technological limitations. Here we present the development, set up, calibration and data quality algorithms for the star photometer at the station of Granada (37.16 N, 3.60 W, 680 m a.s.l.) in Spain. The main advantage of this instrument is that make uses of a CCD camera as detector allowing direct star flux measurements. Filters center at 380, 440, 500, 670, 880 and 1020 nm allows spectral aerosol optical depth (AOD) measurements. Among all the stars, only those that are isolated and possess constant extratarrestial flux are considered. Two methods for the calibration of the system at high mountain places are presented. The first one consists of doing a Langley calibration of a selected star together with measurements of other stars. From the Langley calibration, we transferred AOD and get the calibration constants for other stars. The second method is the Astronomical Langley Method that consists of dividing the measurements by the optical air mass and so more stable calibration constant are obtained. On the other hand, the atmospheric turbulence is important for very short exposure times (< 1 s) and so uncertainties in AOD are of ±0.02 for λ < 800nm and ±0.01 for λ > 800nm. The instrument operated continuously for more than four consecutive years and so a large database was created. Cloud screening and data quality algorithms following AERONET inheritance were developed. Basically, moving averages are applied with different temporal-windows combined with a procedure to detect outliers. On the other hand, with quality data guaranteed the analysis of day-to-night columnar aerosol properties is presented. Mean AOD(440 nm) (0.18 ± 0.10 and 0.19 ± 0.11 for daytime and

  6. Gold nanoparticles in columnar matrix of discotic liquid crystal

    NASA Astrophysics Data System (ADS)

    Supreet, Kumar, Rishi; Pratibha, R.; Kumar, Sandeep; Raina, K. K.

    2013-06-01

    Hexanethiolate-stabilized gold nanoparticles (GNP) were synthesized by the method adopted by Song et al.[2]. Average size of GNPs was determined by scanning transmission electron microscopy (STEM). This method yielded nanoparticles with average particle size of 1.5 nm. In the present work, we have incorporated GNPs in columnar matrix of discotic liquid crystal. The thermo-physical properties of these mixtures were investigated using polarizing optical micrography (POM), differential scanning calorimetry (DSC) and dielectric spectroscopy. Results show GNPs does not affect the hexagonal arrangement of columns of DLC. However, there is decrease in mesophase to crystallization temperature as confirmed by DSC. This approach of crossing of the field of nanotechnology with DLC may lead to novel materials with interesting properties that are useful for many device applications.

  7. Columnar epitaxy of hexagonal and orthorhombic silicides on Si(111)

    NASA Technical Reports Server (NTRS)

    Fathauer, R. W.; Nieh, C. W.; Xiao, Q. F.; Hashimoto, Shin

    1990-01-01

    Columnar grains of PtSi and CrSi2 surrounded by high-quality epitaxial silicon are obtained by ultrahigh vacuum codeposition of Si and metal in an approximately 10:1 ratio on Si(111) substrates heated to 610-840 C. This result is similar to that found previously for CoSi2 (a nearly-lattice-matched cubic-fluorite crystal) on Si(111), in spite of the respective orthorhombic and hexagonal structures of PtSi and CrSi2. The PtSi grains are epitaxial and have one of three variants of the relation defined by PtSi(010)/Si(111), with PtSi 001 line/Si 110 line type.

  8. A novel serrated columnar phased array ultrasonic transducer

    NASA Astrophysics Data System (ADS)

    Zou, Cheng; Sun, Zhenguo; Cai, Dong; Song, Hongwei; Chen, Qiang

    2016-02-01

    Traditionally, wedges are required to generate transverse waves in a solid specimen and mechanical rotation device is needed for interrogation of a specimen with a hollow bore, such as high speed railway locomotive axles, turbine rotors, etc. In order to eliminate the mechanical rotation process, a novel array pattern of phased array ultrasonic transducers named as serrated columnar phased array ultrasonic transducer (SCPAUT) is designed. The elementary transducers are planar rectangular, located on the outside surface of a cylinder. This layout is aimed to generate electrically rotating transverse waveforms so as to inspect the longitudinal cracks on the outside surface of a specimen which has a hollow bore at the center, such as the high speed railway locomotive axles. The general geometry of the SCPAUT and the inspection system are illustrated. A FEM model and mockup experiment has been carried out. The experiment results are in good agreement with the FEM simulation results.

  9. Structural studies in columnar basalts from crystallographic and magnetic fabrics

    NASA Astrophysics Data System (ADS)

    Tiphaine, Boiron; Jérôme, Bascou; Pierre, Camps; Eric, Ferre; Claire, Maurice; Bernard, Guy; Marie-Christine, Gerbe

    2010-05-01

    The purpose of this study is to better characterize the columnar and the associated microstructure development in basalt flows. The thermal contraction (O'Reilly, 1879) is the main hypothesis to explain the columnar formation. However, neither the structures which appear in basalt flow constituted of three levels (Tomkeieff, 1940) nor circular and radial structures within the prisms (for which weathering nor fracturing can account for) can be explained by the thermal contraction theory alone. An early structuring process during solidification (Guy and Le Coze, 1990) could play for a part that must be discussed (Guy, 2010). We studied two recent basalt flows (75 000 years) from the French Massif Central, in which the three flow levels are clearly observed. In the first basalt flow (La Palisse, Ardèche), the emission centre and the flow direction are known. In the second one (Saint Arcons d'Allier, Haute Loire), the prismatic columns are particularly well developed. In order to characterize the flow structure at different scales, from the flow to the grain scale, anisotropy of magnetic susceptibility (AMS) measurements were performed. The AMS data were coupled with crystallographic preferred orientation measurements of magnetite, plagioclase and clinopyroxene using Electron Backscattered Diffraction (EBSD) and image analyses from perpendicular thin sections. Magnetic mineralogy studies of the La Palisse basalts, in particular the thermomagnetic curves, indicate that the main carrier of AMS is high-Ti titanomagnetite (Tc≈130°C). AMS measurements of about a hundred samples show a higher degree of AMS (P parameter) in the middle level in comparison to the base. Inversely, the bulk magnetic susceptibility (Km) is higher at the flow base. Distinctive parameters for the different levels of the basaltic flows could be then provided by AMS measurements.. Moreover, the comparison between AMS and EBSD data indicate that the magnetic susceptibility carried by the magnetic

  10. Electric field controlled columnar and planar patterning of cholesteric colloids.

    PubMed

    D'Adamo, G; Marenduzzo, D; Micheletti, C; Orlandini, E

    2015-05-01

    We study how dispersions of colloidal particles in a cholesteric liquid crystal behave under a time-dependent electric field. By controlling the amplitude and shape of the applied field wave, we show that the system can be reproducibly driven out of equilibrium through different kinetic pathways and navigated through a glassylike free energy landscape encompassing many competing metastable equilibria. Such states range from simple Saturn rings to complex structures featuring amorphous defect networks, or stacks of disclination loops. A nonequilibrium electric field can also trigger the alignment of particles into columnar arrays, through defect-mediated force impulses, or their repositioning within a plane. Our results are promising in terms of providing new avenues towards controlled patterning and self-assembly of soft colloid-liquid crystal composite materials. PMID:25978263

  11. Electric field controlled columnar and planar patterning of cholesteric colloids.

    PubMed

    D'Adamo, G; Marenduzzo, D; Micheletti, C; Orlandini, E

    2015-05-01

    We study how dispersions of colloidal particles in a cholesteric liquid crystal behave under a time-dependent electric field. By controlling the amplitude and shape of the applied field wave, we show that the system can be reproducibly driven out of equilibrium through different kinetic pathways and navigated through a glassylike free energy landscape encompassing many competing metastable equilibria. Such states range from simple Saturn rings to complex structures featuring amorphous defect networks, or stacks of disclination loops. A nonequilibrium electric field can also trigger the alignment of particles into columnar arrays, through defect-mediated force impulses, or their repositioning within a plane. Our results are promising in terms of providing new avenues towards controlled patterning and self-assembly of soft colloid-liquid crystal composite materials.

  12. Experimental study of columnar recombination in fission chambers

    NASA Astrophysics Data System (ADS)

    Filliatre, P.; Lamirand, V.; Geslot, B.; Jammes, C.

    2016-05-01

    In this paper, we present experimental saturation curves of a small gap miniature fission chamber obtained in the MINERVE reactor. The chamber is filled with argon at various pressures, and the fissile material can be coated on the anode, cathode, or both. For analyzing the recombination regime, we consider a model of columnar recombination and discuss its applicability to our chamber. By applying this model to the data, it is possible to estimate the ratio between the recombination coefficient k and an effective column radius b, appearing in the model, to be k / b =(2.5 ± 0.9) ×10-6m2 / s for argon. From these results, a routine measurement of the recombination regime is proposed in order to detect gas leakage. This online diagnosis would be beneficial in terms of lifetime and reliability of the neutron instrumentation of nuclear reactors.

  13. Azimuthal Frustration and Bundling in Columnar DNA Aggregates

    PubMed Central

    Harreis, H. M.; Likos, C. N.; Löwen, H.

    2003-01-01

    The interaction between two stiff parallel DNA molecules is discussed using linear Debye-Hückel screening theory with and without inclusion of the dielectric discontinuity at the DNA surface, taking into account the helical symmetry of DNA. The pair potential furthermore includes the amount and distribution of counterions adsorbed on the DNA surface. The interaction does not only depend on the interaxial separation of two DNA molecules, but also on their azimuthal orientation. The optimal mutual azimuthal angle is a function of the DNA-DNA interaxial separation, which leads to azimuthal frustrations in an aggregate. On the basis of the pair potential, the positional and orientational order in columnar B-DNA assemblies in solution is investigated. Phase diagrams are calculated using lattice sums supplemented with the entropic contributions of the counterions in solution. A variety of positionally and azimuthally ordered phases and bundling transitions is predicted, which strongly depend on the counterion adsorption patterns. PMID:12770870

  14. Nopal cactus (Opuntia ficus-indica) as a source of bioactive compounds for nutrition, health and disease.

    PubMed

    El-Mostafa, Karym; El Kharrassi, Youssef; Badreddine, Asmaa; Andreoletti, Pierre; Vamecq, Joseph; El Kebbaj, M'Hammed Saïd; Latruffe, Norbert; Lizard, Gérard; Nasser, Boubker; Cherkaoui-Malki, Mustapha

    2014-01-01

    Opuntia ficus-indica, commonly referred to as prickly pear or nopal cactus, is a dicotyledonous angiosperm plant. It belongs to the Cactaceae family and is characterized by its remarkable adaptation to arid and semi-arid climates in tropical and subtropical regions of the globe. In the last decade, compelling evidence for the nutritional and health benefit potential of this cactus has been provided by academic scientists and private companies. Notably, its rich composition in polyphenols, vitamins, polyunsaturated fatty acids and amino acids has been highlighted through the use of a large panel of extraction methods. The identified natural cactus compounds and derivatives were shown to be endowed with biologically relevant activities including anti-inflammatory, antioxidant, hypoglycemic, antimicrobial and neuroprotective properties. The present review is aimed at stressing the major classes of cactus components and their medical interest through emphasis on some of their biological effects, particularly those having the most promising expected health benefit and therapeutic impacts. PMID:25232708

  15. Nopal cactus (Opuntia ficus-indica) as a source of bioactive compounds for nutrition, health and disease.

    PubMed

    El-Mostafa, Karym; El Kharrassi, Youssef; Badreddine, Asmaa; Andreoletti, Pierre; Vamecq, Joseph; El Kebbaj, M'Hammed Saïd; Latruffe, Norbert; Lizard, Gérard; Nasser, Boubker; Cherkaoui-Malki, Mustapha

    2014-09-17

    Opuntia ficus-indica, commonly referred to as prickly pear or nopal cactus, is a dicotyledonous angiosperm plant. It belongs to the Cactaceae family and is characterized by its remarkable adaptation to arid and semi-arid climates in tropical and subtropical regions of the globe. In the last decade, compelling evidence for the nutritional and health benefit potential of this cactus has been provided by academic scientists and private companies. Notably, its rich composition in polyphenols, vitamins, polyunsaturated fatty acids and amino acids has been highlighted through the use of a large panel of extraction methods. The identified natural cactus compounds and derivatives were shown to be endowed with biologically relevant activities including anti-inflammatory, antioxidant, hypoglycemic, antimicrobial and neuroprotective properties. The present review is aimed at stressing the major classes of cactus components and their medical interest through emphasis on some of their biological effects, particularly those having the most promising expected health benefit and therapeutic impacts.

  16. Grain texture evolution during the columnar growth of dendritic alloys

    NASA Astrophysics Data System (ADS)

    Gandin, Ch. A.; Rappaz, M.; West, D.; Adams, B. L.

    1995-06-01

    The grain selection that operates in the columnar zone of a directionally solidified (DS) INCONEL X750 superalloy has been investigated using standard metallography and an automatic indexing technique of electron backscattered diffraction patterns (EBSPs). From the crystallographic orientations measured at 90,000 points in a longitudinal section, the grain structure was reconstructed. The grain density as measured by the inverse of the mean linear intercept was found to be a decreasing function of the distance from the chill. The evolution of the <100> pole figures along the columnar zone of the casting and the distribution of the angle θ characterizing the <100> direction of the grains that is closest to the temperature gradient were then deduced from the EBSPs measurement. It was found that, near the surface of the chill, the θ distribution was close to the theoretical curve calculated for randomly oriented grains. As the distance from the chill increased, the measured θ distribution became narrower and was displaced toward smaller θ values. At 2 mm from the chill, the most probable orientation of the grains was found to be about 0.21 rad (12 deg). The information obtained with the EBSPs was then compared with the results of a three-dimensional stochastic model (3D SM) describing the formation of grain structure during solidification. This model accounts for the random location and orientation of the nuclei, for the growth kinetics and preferential <100> growth directions of the dendrites. Although this model assumes a uniform temperature within the specimen, the simulation results were found to be in good agreement with the EBSPs measurement.

  17. Interobserver reproducibility in pathologist interpretation of columnar-lined esophagus.

    PubMed

    Mastracci, Luca; Piol, Nataniele; Molinaro, Luca; Pitto, Francesca; Tinelli, Carmine; De Silvestri, Annalisa; Fiocca, Roberto; Grillo, Federica

    2016-02-01

    Confirmation of endoscopically suspected esophageal metaplasia (ESEM) requires histology, but confusion in the histological definition of columnar-lined esophagus (CLE) is a longstanding problem. The aim of this study is to evaluate interpathologist variability in the interpretation of CLE. Thirty pathologists were invited to review three ten-case sets of CLE biopsies. In the first set, the cases were provided with descriptive endoscopy only; in the second and the third sets, ESEM extent using Prague criteria was provided. Moreover, participants were required to refer to a diagnostic chart for evaluation of the third set. Agreement was statistically assessed using Randolph's free-marginal multirater kappa. While substantial agreement in recognizing columnar epithelium (K = 0.76) was recorded, the overall concordance in clinico-pathological diagnosis was low (K = 0.38). The overall concordance rate improved from the first (K = 0.27) to the second (K = 0.40) and third step (K = 0.46). Agreement was substantial when diagnosing Barrett's esophagus (BE) with intestinal metaplasia or inlet patch (K = 0.65 and K = 0.89), respectively, in the third step, while major problems in interpretation of CLE were observed when only cardia/cardia-oxyntic atrophic-type epithelium was present (K = 0.05-0.29). In conclusion, precise endoscopic description and the use of a diagnostic chart increased consistency in CLE interpretation of esophageal biopsies. Agreement was substantial for some diagnostic categories (BE with intestinal metaplasia and inlet patch) with a well-defined clinical profile. Interpretation of cases with cardia/cardia-oxyntic atrophic-type epithelium, with or without ESEM, was least consistent, which reflects lack of clarity of definition and results in variable management of this entity.

  18. Microseismic monitoring of columnar jointed basalt fracture activity: a trial at the Baihetan Hydropower Station, China

    NASA Astrophysics Data System (ADS)

    Chen, Bing-Rui; Li, Qing-Peng; Feng, Xia-Ting; Xiao, Ya-Xun; Feng, Guang-Liang; Hu, Lian-Xing

    2014-10-01

    Severe stress release has occurred to the surrounding rocks of the typically columnar jointed basalt after excavation at the Baihetan Hydropower Station, Jinsha River, China, where cracking, collapse, and other types of failure may take place occasionally due to relaxation fracture. In order to understand the relaxation fracture characteristics of the columnar jointed basalt in the entire excavation process at the diversion tunnel of the Baihetan Hydropower Station, real-time microseismic monitoring tests were performed. First, the applicability of a geophone and accelerometer was analyzed in the columnar jointed basalt tunnel, and the results show that the accelerometer was more applicable to the cracking monitoring of the columnar jointed basalt. Next, the waveform characteristics of the microseismic signals were analyzed, and the microseismic signals were identified as follows: rock fracture signal, drilling signal, electrical signal, heavy vehicle passing signal, and blast signal. Then, the attenuation characteristics of the microseismic signals in the columnar jointed basalt tunnel were studied, as well as the types and characteristics of the columnar jointed basalt fracture. Finally, location analysis was conducted on the strong rock fracture events, in which four or more sensors were triggered, to obtain the temporal and spatial evolution characteristics and laws of the columnar jointed basalt relaxation fracture after excavation. The test results are not only of important reference value to the excavation and support of diversion tunnel at the Baihetan Hydropower Station, but also of great referential significance and value to the conduction of similar tests.

  19. Transition between columnar absorptive cells and goblet cells in the rat jejunal epithelium.

    PubMed

    Kurosumi, K; Shibuichi, I; Tosaka, H

    1981-11-01

    Electron microscopic observation of the jejunal epithelium of rats demonstrated morphological evidence of a transition between columnar absorptive cells and growing goblet cells. The columnar cells in both the villi and crypts have features suggestive of absorptive functions. They are provided with apical invaginations continuous to the intermicrovillous space. Absorbed lipid is observed in small vesicles in the terminal web layer, and chylomicrons derived here from are contained in large vacuoles near the Golgi apparatus. Ferritin particles artificially infused into the gut lumen were absorbed into the vacuoles in the subapical zone of columnar cells of suckling rats. Growing goblet cells situated in the crypt epithelium contain surface invaginations and lysosomes which are the same in structure as those found in absorptive cells nearby. Fat droplets evidently absorbed by the growing goblet cell were observed among immature mucus droplets. Artificially infused ferritin particles were found in vacuoles and lysosomes near the Golgi apparatus of some goblet cells of suckling rats. Some goblet cells on the intestinal villi of suckling rats looked immature and their microvilli and cytoplasmic matrix were clear like those of columnar absorptive cells. The transition between these goblet cells with clear cytoplasm and the mature goblet cells with dark cytoplasm was observed. These morphological evidences indicate that some of columnar cells already differentiated to absorptive cells are capable of transforming into mucus-producing (goblet) cells. It is suggested that not only undifferentiated columnar cells in the crypt base but also considerably differentiated columnar cells with absorptive function can differentiate into goblet cells.

  20. Integrating the Forensic Sciences in Wildlife Case Investigations: A Case Report of Pentobarbital and Phenytoin Toxicosis in a Bald Eagle (Haliaeetus leucocephalus).

    PubMed

    Viner, T C; Hamlin, B C; McClure, P J; Yates, B C

    2016-09-01

    The application of medical knowledge to the purpose of law is the foundation of forensic pathology. A forensic postmortem examination often involves the expertise of multiple scientific disciplines to reconstruct the full story surrounding the death of an animal. Wildlife poses additional challenges in forensic investigations due to little or no associated history, and the disruptive effects of decomposition. To illustrate the multidisciplinary nature of wildlife forensic medicine, the authors outline a case of secondary pentobarbital/phenytoin toxicosis in a bald eagle (Haliaeetus leucocephalus). The eagle was the single fatality in a group of 8 birds that fed on euthanized domestic cat remains that had been improperly disposed of in a landfill. Cooperation between responding law enforcement officers, pathologists, and other forensic scientists led to the successful diagnosis and resolution of the case.

  1. Integrating the Forensic Sciences in Wildlife Case Investigations: A Case Report of Pentobarbital and Phenytoin Toxicosis in a Bald Eagle (Haliaeetus leucocephalus).

    PubMed

    Viner, T C; Hamlin, B C; McClure, P J; Yates, B C

    2016-09-01

    The application of medical knowledge to the purpose of law is the foundation of forensic pathology. A forensic postmortem examination often involves the expertise of multiple scientific disciplines to reconstruct the full story surrounding the death of an animal. Wildlife poses additional challenges in forensic investigations due to little or no associated history, and the disruptive effects of decomposition. To illustrate the multidisciplinary nature of wildlife forensic medicine, the authors outline a case of secondary pentobarbital/phenytoin toxicosis in a bald eagle (Haliaeetus leucocephalus). The eagle was the single fatality in a group of 8 birds that fed on euthanized domestic cat remains that had been improperly disposed of in a landfill. Cooperation between responding law enforcement officers, pathologists, and other forensic scientists led to the successful diagnosis and resolution of the case. PMID:27030371

  2. The effect of variety and location on cactus pear (Opuntia ficus-indica) fruit quality.

    PubMed

    de Wit, Maryna; Nel, Philip; Osthoff, Gernot; Labuschagne, Maryke T

    2010-06-01

    Little is known about the performance of South African cactus pear varieties in different agro-ecological regions. Effects of locality on internal quality parameters of available cactus pear varieties were examined. With only one exception, no significant differences among the mean replication values for the different parameters between the different locations were observed. The differences between mean values for most individual parameters at the three localities were highly significant. Highly significant differences between the mean values for the measured characteristics were observed, not only among the locations (except for the pulp glucose values), but also for the influences of genotype and interaction between locality and genotype. Significant variations existed between mean values of the different characteristics between localities. Genotype x environmental interactions were noted. It was concluded that Meyers is the most appropriate cultivar for economical purposes in South Africa.

  3. Fish and wildlife to determine endangered status of San Rafael Cactus

    SciTech Connect

    Not Available

    1986-09-01

    The US Fish and Wildlife Service has proposed to determine the endangered status of the San Rafael Cactus. Although the only known occurrences of the species do not appear to fall within the boundaries of the San Rafael Swell Special Tar Sands Area, nearby combined hydrocarbon leasing could be impacted. There are two known populations of Pediocactus despainii, about 25 miles apart and each containing 2000 to 3000 individuals. Both occur in central Utah (Emery County), mainly in areas administered by the Bureau of Land Management. This rare species is being sought be cactus collectors, one population is heavily impacted by recreational off-road vehicles, and approximately one-half of each population is in areas covered by oil and gas leases and/or mining claims for gypsum. If the species is determined to be endangered, then the Fish and Wildlife Service could define a critical habitat for its preservation.

  4. Divergence in olfactory host plant preference in D. mojavensis in response to cactus host use.

    PubMed

    Date, Priya; Dweck, Hany K M; Stensmyr, Marcus C; Shann, Jodi; Hansson, Bill S; Rollmann, Stephanie M

    2013-01-01

    Divergence in host adaptive traits has been well studied from an ecological and evolutionary perspective, but identification of the proximate mechanisms underlying such divergence is less well understood. Behavioral preferences for host plants are often mediated by olfaction and shifts in preference may be accompanied by changes in the olfactory system. In this study, we examine the evolution of host plant preferences in cactophilic Drosophila mojavensis that feeds and breeds on different cacti throughout its range. We show divergence in electrophysiological responses and olfactory behavior among populations with host plant shifts. Specifically, significant divergence was observed in the Mojave Desert population that specializes on barrel cactus. Differences were observed in electrophysiological responses of the olfactory organs and in behavioral responses to barrel cactus volatiles. Together our results suggest that the peripheral nervous system has changed in response to different ecological environments and that these changes likely contribute to divergence among D. mojavensis populations.

  5. Divergence in Olfactory Host Plant Preference in D. mojavensis in Response to Cactus Host Use

    PubMed Central

    Stensmyr, Marcus C.; Shann, Jodi; Hansson, Bill S.; Rollmann, Stephanie M.

    2013-01-01

    Divergence in host adaptive traits has been well studied from an ecological and evolutionary perspective, but identification of the proximate mechanisms underlying such divergence is less well understood. Behavioral preferences for host plants are often mediated by olfaction and shifts in preference may be accompanied by changes in the olfactory system. In this study, we examine the evolution of host plant preferences in cactophilic Drosophila mojavensis that feeds and breeds on different cacti throughout its range. We show divergence in electrophysiological responses and olfactory behavior among populations with host plant shifts. Specifically, significant divergence was observed in the Mojave Desert population that specializes on barrel cactus. Differences were observed in electrophysiological responses of the olfactory organs and in behavioral responses to barrel cactus volatiles. Together our results suggest that the peripheral nervous system has changed in response to different ecological environments and that these changes likely contribute to divergence among D. mojavensis populations. PMID:23936137

  6. Derivation of Aerosol Columnar Mass from MODIS Optical Depth

    NASA Technical Reports Server (NTRS)

    Gasso, Santiago; Hegg, Dean A.

    2003-01-01

    In order to verify performance, aerosol transport models (ATM) compare aerosol columnar mass (ACM) with those derived from satellite measurements. The comparison is inherently indirect since satellites derive optical depths and they use a proportionality constant to derive the ACM. Analogously, ATMs output a four dimensional ACM distribution and the optical depth is linearly derived. In both cases, the proportionality constant requires a direct intervention of the user by prescribing the aerosol composition and size distribution. This study introduces a method that minimizes the direct user intervention by making use of the new aerosol products of MODIS. A parameterization is introduced for the derivation of columnar aerosol mass (AMC) and CCN concentration (CCNC) and comparisons between sunphotometer, MODIS Airborne Simulator (MAS) and in-measurements are shown. The method still relies on the scaling between AMC and optical depth but the proportionality constant is dependent on the MODIS derived r$_{eff}$,\\eta (contribution of the accumulation mode radiance to the total radiance), ambient RH and an assumed constant aerosol composition. The CCNC is derived fkom a recent parameterization of CCNC as a function of the retrieved aerosol volume. By comparing with in-situ data (ACE-2 and TARFOX campaigns), it is shown that retrievals in dry ambient conditions (dust) are improved when using a proportionality constant dependent on r$ {eff}$ and \\eta derived in the same pixel. In high humidity environments, the improvement inthe new method is inconclusive because of the difficulty in accounting for the uneven vertical distribution of relative humidity. Additionally, two detailed comparisons of AMC and CCNC retrieved by the MAS algorithm and the new method are shown. The new method and MAS retrievals of AMC are within the same order of magnitude with respect to the in-situ measurements of aerosol mass. However, the proposed method is closer to the in-situ measurements than

  7. Analysis of core soil and water samples from the Cactus Crater Disposal Site at Enewetak atoll

    SciTech Connect

    Robison, W.L.; Noshkin, V.E.

    1981-02-18

    Core soil samples and water samples were collected from the Cactus Crater Disposal Site at Enewetak for analysis of /sup 137/Cs, /sup 90/Sr, /sup 239 +240/Pu and /sup 241/Am by both gamma spectroscopy and, through a contractor laboratory, by wet chemistry procedures. The samples processing methods, the analytical methods and the analytical quality control are all procedures developed for the continuing Marshall Island radioecology and dose assessment work.

  8. Intestinal bioaccessibility of polyphenols and antioxidant capacity of pulp and seeds of cactus pear.

    PubMed

    Ramírez-Moreno, E; Hervert-Hernández, D; Sánchez-Mata, M C; Díez-Marqués, C; Goñi, I

    2011-12-01

    The aim of this work was to estimate the intestinal bioaccessibility of polyphenols and antioxidant capacity of cactus pear using an in vitro gastrointestinal model. The amount of polyphenols released from the food matrix by the action of digestive enzymes was about 69-83% in pulp and 0-14% in seeds. The rest of polyphenols was associated with indigestible compounds conferring antioxidant capacity. The results suggest that these compounds could reach the colon and induce healthy effects.

  9. Habitat fragmentation in coastal southern California disrupts genetic connectivity in the cactus wren (Campylorhynchus brunneicapillus).

    PubMed

    Barr, Kelly R; Kus, Barbara E; Preston, Kristine L; Howell, Scarlett; Perkins, Emily; Vandergast, Amy G

    2015-05-01

    Achieving long-term persistence of species in urbanized landscapes requires characterizing population genetic structure to understand and manage the effects of anthropogenic disturbance on connectivity. Urbanization over the past century in coastal southern California has caused both precipitous loss of coastal sage scrub habitat and declines in populations of the cactus wren (Campylorhynchus brunneicapillus). Using 22 microsatellite loci, we found that remnant cactus wren aggregations in coastal southern California comprised 20 populations based on strict exact tests for population differentiation, and 12 genetic clusters with hierarchical Bayesian clustering analyses. Genetic structure patterns largely mirrored underlying habitat availability, with cluster and population boundaries coinciding with fragmentation caused primarily by urbanization. Using a habitat model we developed, we detected stronger associations between habitat-based distances and genetic distances than Euclidean geographic distance. Within populations, we detected a positive association between available local habitat and allelic richness and a negative association with relatedness. Isolation-by-distance patterns varied over the study area, which we attribute to temporal differences in anthropogenic landscape development. We also found that genetic bottleneck signals were associated with wildfire frequency. These results indicate that habitat fragmentation and alterations have reduced genetic connectivity and diversity of cactus wren populations in coastal southern California. Management efforts focused on improving connectivity among remaining populations may help to ensure population persistence.

  10. Protective effect of cactus (Opuntia ficus indica) cladode extract upon nickel-induced toxicity in rats.

    PubMed

    Hfaiedh, Najla; Allagui, Mohamed Salah; Hfaiedh, Mbarka; Feki, Abdelfattah El; Zourgui, Lazhar; Croute, Françoise

    2008-12-01

    The purpose of this study carried out on male Wistar rats, was to evaluate the protective effects of regular ingestion of juice from the prickly pear cactus (Opuntia ficus indica) cladodes against nickel chloride toxicity. Rats were given either normal tap water or water containing 25% of cactus juice for one month. Then, rats of each group were injected daily, for 10 days, with either NiCl(2) solution (4mg (30micromol)/kg body weight) or with the same volume of saline solution (300mM NaCl). Significant increases of lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase activities and of cholesterol, triglycerides and glucose levels were observed in blood of nickel-treated rats. In the liver, nickel chloride was found to induce an oxidative stress evidenced by an increase in lipid peroxidation and changes in antioxidant enzymes activities. Superoxide-dismutase (SOD) activity was found to be increased whereas glutathione peroxidase and catalase activities were decreased. These changes did not occur in animals previously given cactus juice, demonstrating a protective effect of this vegetal extract.

  11. Dark matter and gamma-rays from Draco: MAGIC, GLAST and CACTUS

    SciTech Connect

    Bergstrom, Lars; Hooper, Dan; /Fermilab

    2005-12-01

    The dwarf spheroidal galaxy Draco has long been considered likely to be one of the brightest point sources of gamma-rays generated through dark matter annihilations. Recent studies of this object have found that it remains largely intact from tidal striping, and may be more massive than previously thought. In this article, we revisit Draco as a source of dark matter annihilation radiation, with these new observational constraints in mind. We discuss the prospects for the experiments MAGIC and GLAST to detect dark matter in Draco, as well as constraints from the observations of EGRET. We also discuss the possibility that the CACTUS experiment has already detected gamma-rays from Draco. We find that it is difficult to generate the flux reported by CACTUS without resorting to non-thermally produced WIMPs and/or a density spike in Draco's dark matter distribution due to the presence of an intermediate mass black hole. We also find that for most annihilation modes, a positive detection of Draco by CACTUS would be inconsistent with the lack of events seen by EGRET.

  12. Dark matter and gamma rays from Draco: MAGIC, GLAST and CACTUS

    SciTech Connect

    Bergstroem, Lars; Hooper, Dan

    2006-03-15

    The dwarf spheroidal galaxy Draco has long been considered likely to be one of the brightest point sources of gamma rays generated through dark matter annihilations. Recent studies of this object have found that it remains largely intact from tidal striping, and may be more massive than previously thought. In this article, we revisit Draco as a source of dark matter annihilation radiation, with these new observational constraints in mind. We discuss the prospects for the experiments MAGIC and GLAST to detect dark matter in Draco, as well as constraints from the observations of EGRET. We also discuss the possibility that the CACTUS experiment has already detected gamma rays from Draco. We find that it is difficult to generate the flux reported by CACTUS without resorting to nonthermally produced WIMPs and/or a density spike in Draco's dark matter distribution due to the presence of an intermediate mass black hole. We also find that for most annihilation modes, a positive detection of Draco by CACTUS would be inconsistent with the lack of events seen by EGRET.

  13. Habitat fragmentation in coastal southern California disrupts genetic connectivity in the cactus wren (Campylorhynchus brunneicapillus)

    USGS Publications Warehouse

    Barr, Kelly R.; Kus, Barbara E.; Preston, Kristine; Howell, Scarlett; Perkins, Emily; Vandergast, Amy

    2015-01-01

    Achieving long-term persistence of species in urbanized landscapes requires characterizing population genetic structure to understand and manage the effects of anthropogenic disturbance on connectivity. Urbanization over the past century in coastal southern California has caused both precipitous loss of coastal sage scrub habitat and declines in populations of the cactus wren (Campylorhynchus brunneicapillus). Using 22 microsatellite loci, we found that remnant cactus wren aggregations in coastal southern California comprised 20 populations based on strict exact tests for population differentiation, and 12 genetic clusters with hierarchical Bayesian clustering analyses. Genetic structure patterns largely mirrored underlying habitat availability, with cluster and population boundaries coinciding with fragmentation caused primarily by urbanization. Using a habitat model we developed, we detected stronger associations between habitat-based distances and genetic distances than Euclidean geographic distance. Within populations, we detected a positive association between available local habitat and allelic richness and a negative association with relatedness. Isolation-by-distance patterns varied over the study area, which we attribute to temporal differences in anthropogenic landscape development. We also found that genetic bottleneck signals were associated with wildfire frequency. These results indicate that habitat fragmentation and alterations have reduced genetic connectivity and diversity of cactus wren populations in coastal southern California. Management efforts focused on improving connectivity among remaining populations may help to ensure population persistence.

  14. Protective effect of cactus (Opuntia ficus indica) cladode extract upon nickel-induced toxicity in rats.

    PubMed

    Hfaiedh, Najla; Allagui, Mohamed Salah; Hfaiedh, Mbarka; Feki, Abdelfattah El; Zourgui, Lazhar; Croute, Françoise

    2008-12-01

    The purpose of this study carried out on male Wistar rats, was to evaluate the protective effects of regular ingestion of juice from the prickly pear cactus (Opuntia ficus indica) cladodes against nickel chloride toxicity. Rats were given either normal tap water or water containing 25% of cactus juice for one month. Then, rats of each group were injected daily, for 10 days, with either NiCl(2) solution (4mg (30micromol)/kg body weight) or with the same volume of saline solution (300mM NaCl). Significant increases of lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase activities and of cholesterol, triglycerides and glucose levels were observed in blood of nickel-treated rats. In the liver, nickel chloride was found to induce an oxidative stress evidenced by an increase in lipid peroxidation and changes in antioxidant enzymes activities. Superoxide-dismutase (SOD) activity was found to be increased whereas glutathione peroxidase and catalase activities were decreased. These changes did not occur in animals previously given cactus juice, demonstrating a protective effect of this vegetal extract. PMID:18950672

  15. Habitat fragmentation in coastal southern California disrupts genetic connectivity in the cactus wren (Campylorhynchus brunneicapillus).

    PubMed

    Barr, Kelly R; Kus, Barbara E; Preston, Kristine L; Howell, Scarlett; Perkins, Emily; Vandergast, Amy G

    2015-05-01

    Achieving long-term persistence of species in urbanized landscapes requires characterizing population genetic structure to understand and manage the effects of anthropogenic disturbance on connectivity. Urbanization over the past century in coastal southern California has caused both precipitous loss of coastal sage scrub habitat and declines in populations of the cactus wren (Campylorhynchus brunneicapillus). Using 22 microsatellite loci, we found that remnant cactus wren aggregations in coastal southern California comprised 20 populations based on strict exact tests for population differentiation, and 12 genetic clusters with hierarchical Bayesian clustering analyses. Genetic structure patterns largely mirrored underlying habitat availability, with cluster and population boundaries coinciding with fragmentation caused primarily by urbanization. Using a habitat model we developed, we detected stronger associations between habitat-based distances and genetic distances than Euclidean geographic distance. Within populations, we detected a positive association between available local habitat and allelic richness and a negative association with relatedness. Isolation-by-distance patterns varied over the study area, which we attribute to temporal differences in anthropogenic landscape development. We also found that genetic bottleneck signals were associated with wildfire frequency. These results indicate that habitat fragmentation and alterations have reduced genetic connectivity and diversity of cactus wren populations in coastal southern California. Management efforts focused on improving connectivity among remaining populations may help to ensure population persistence. PMID:25819510

  16. Scale selection in columnar jointing: Insights from experiments on cooling stearic acid and numerical simulations

    NASA Astrophysics Data System (ADS)

    Christensen, Amalie; Raufaste, Christophe; Misztal, Marek; Celestini, Franck; Guidi, Maria; Ellegaard, Clive; Mathiesen, Joachim

    2016-03-01

    Many natural fracture systems are characterized by a single length scale, which is the distance between neighboring fractures. Examples are mud cracks and columnar jointing. In columnar jointing the origin of this scale has been a long-standing issue. Here we present a comprehensive study of columnar jointing based on experiments on cooling stearic acids, numerical simulations using both discrete and finite element methods and basic analytical calculations. We show that the diameter of columnar joints is a nontrivial function of the material properties and the cooling conditions of the system. We determine the shape of this function analytically and show that it is in agreement with the experiments and the numerical simulations.

  17. A New Phase of Liquid Crystal with Quenched Disorder: The Columnar Elastic Glass

    NASA Astrophysics Data System (ADS)

    Toner, John; Saunders, Karl; Ettouhami, A. M.; Radzihovsky, Leo

    2002-03-01

    The properties of the columnar liquid crystal phase confined in random porous media, e.g. aerogel, are studied. It is found that the quenched disorder leads to a complete destruction of the long-ranged columnar translational order. Nevertheless, dislocations remain bound in the resulting phase, which therefore retains columnar topological and orientational order, and is referred to as a columnar elastic glass (CEG). The elasticity of the CEG is found to be anomalous, i.e. wavevector dependent, and is characterized by universal anomalous exponents, which are calculated using an ɛ = 7/2 - d expansion. The CEG also exhibits a negative universal Poisson ratio which is calculated. Furthemore, the recently predicted spontaneous vortex lattice in dirty ferromagnetic superconductors falls into the CEG universality class [1]. [1] Leo Radzihovsky, A. M. Ettouhami, Karl Saunders, John Toner, Phys. Rev. Lett.87, 27001 (2001).

  18. Growth of columnar hydrogel colloidal crystals in water-organic solvent mixture.

    PubMed

    Zhou, Jun; Cai, Tong; Tang, Shijun; Marquez, Manuel; Hu, Zhibing

    2006-01-31

    A novel emulsion method has been demonstrated to grow columnar hydrogel colloidal crystals by mixing an aqueous suspension of poly-N-isopropylacrylamide-co-allylamine microgels with organic solvent, driven by the coalescence of micelles consisting of organic oil droplets coated by many microgels. This method leads to microgel colloidal crystals of several centimeters growing from the top to the bottom along the gravity direction. Both temperature and polymer concentration play critical roles for the formation of columnar crystals. A phase diagram has been determined, and it can be used as a guide to selectively grow different crystals, including columnar crystals and randomly oriented crystals, and enable the coexistence of columnar crystals and randomly oriented crystals.

  19. Formalin treatment of Trichondina sp. reduced Flavobacterium columnare infection in tilapia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterium Flavobacterium columnare and protozoan Trichodina spp. are common pathogens of cultured fish. Recent studies on parasite-bacterium interaction show evidence that concurrent infections increase severity of some infectious diseases, especially bacterial diseases. The effect of parasite treat...

  20. Anisotropic Bruggeman effective medium approaches for slanted columnar thin films

    NASA Astrophysics Data System (ADS)

    Schmidt, Daniel; Schubert, Mathias

    2013-08-01

    Two different formalisms for the homogenization of composite materials containing ellipsoidal inclusions based on Bruggeman's original formula for spherical inclusions can be found in the literature. Both approximations determine the effective macroscopic permittivity of such an idealized composite assuming randomly distributed dielectric particles of equal shape and differ only in the definition of the depolarization factors. The two approaches are applied to analyze ellipsometric Mueller matrix spectra acquired in the visible and near-infrared spectral region from metal and semiconductor slanted columnar thin films. Furthermore, the effective dielectric function tensor generated by the two Bruggeman formalisms is compared to effective major axes dielectric functions individually determined with a homogeneous biaxial layer approach. Best-match model parameters of all three model approaches are discussed and compared to estimates from scanning electron microscope images. The structural parameters obtained from all three optical modeling approaches agree well with the electron microscopy technique. A comparative discussion is given for the validity and applicability of the three model approaches for analysis of future devices structures that may require optical readout using generalized ellipsometry methods.

  1. Numerical Investigation of Synthetic Buoyancy-Induced Columnar Vortices

    NASA Astrophysics Data System (ADS)

    Malaya, Nicholas; Stogner, Roy; Moser, Robert

    2015-11-01

    Much of the solar energy incident on the Earth's surface is absorbed into the ground, which in turn heats the air layer above the surface. This buoyant air layer contains considerable gravitational potential energy. The energy can drive the formation of columnar vortices (``Dust-Devils'') which arise naturally in the atmosphere. These ``Dust-Devils'' occur over a wide range of scales in many different locations across the Earth, as well as on Mars. A new energy harvesting approach makes use of this ubiquitous process by creating and anchoring the vortices artificially and extracting energy from them. In this talk we explore the characteristics of these vorticies through numerical simulation. Computational models of the turning vane system used to generate the vortex have been developed. We will discuss the formulation of these models and their validation against available experimental measurements. We will also describe the use of these simulations to optimize the turning vane configuration to maximize the power extraction, as well as serving as a vehicle to probe the dynamics of the underlying physical processes. Finally, this talk will conclude with comparisons between the synthetic vorticies and the naturally occurring phenomena. This work supported by the Department of Energy [ARPA-E] under Award Number [DE-FOA-0000670].

  2. Evolving fracture patterns: columnar joints, mud cracks and polygonal terrain.

    PubMed

    Goehring, Lucas

    2013-01-01

    When cracks form in a thin contracting layer, they sequentially break the layer into smaller and smaller pieces. A rectilinear crack pattern encodes information about the order of crack formation, as later cracks tend to intersect with earlier cracks at right angles. In a hexagonal pattern, in contrast, the angles between all cracks at a vertex are near 120°. Hexagonal crack patterns are typically seen when a crack network opens and heals repeatedly, in a thin layer, or advances by many intermittent steps into a thick layer. Here, it is shown how both types of pattern can arise from identical forces, and how a rectilinear crack pattern can evolve towards a hexagonal one. Such an evolution is expected when cracks undergo many opening cycles, where the cracks in any cycle are guided by the positions of cracks in the previous cycle but when they can slightly vary their position and order of opening. The general features of this evolution are outlined and compared with a review of the specific patterns of contraction cracks in dried mud, polygonal terrain, columnar joints and eroding gypsum-sand cements.

  3. Statistic study on developing condition of horizontal columnar joints in Jeongja and Eupchon beach areas, SE Korea

    NASA Astrophysics Data System (ADS)

    Jin, K.; Kim, Y.; Geologic Structure; Geohazard Research Group

    2010-12-01

    Unusual patterns of columnar joints are developed in Tertiary volcanic rocks along the Jeongja and Eupchon beach areas, SE Korea. The columnar joints represent various features in shape and orientation, including horizontal and inclined column distribution. The shape and orientation of columnar joints were statistically analyzed to understand the causes of the unusual column patterns. For this purpose, the shape of the column face perpendicular to the column direction and the trend and plunge of the column are analyzed. Most columnar joints in the study areas have five or six column faces, and the column diameter perpendicular to the column direction is in a range of between 30 to 50 cm. Columnar joints generally develop vertically due to cooling from both top and bottom surfaces. However, unusual horizontal and inclined columnar joints are observed in the study areas. Therefore, the horizontal and inclined columnar joints developed in the study areas may suggest abnormal cooling condition. The volcanic rocks in the study areas intruded or extruded in late Miocene (22-16 Ma), which coincides with a period of high sea level in the Miocene. The sea level is almost the same as the present sea level. This may suggest that the unusual columnar joint patterns that have developed in the study areas may have been affected by sea water. Therefore, if the characteristics of these columnar joints are more intensively studied on a morphological, petrological, geochemical, and chronological level, we can better understand the developing mechanism of horizontal columnar joints.

  4. Review of samples of sediment, tailings, and waters adjacent to the Cactus Queen gold mine, Kern County, California

    USGS Publications Warehouse

    Rytuba, James J.; Kim, Christopher S.; Goldstein, Daniel N.

    2011-01-01

    The Cactus Queen Mine is located in the western Mojave Desert in Kern County, California. The Cactus Queen gold-silver (Au-Ag) deposit is similar to other Au-Ag deposits hosted in Miocene volcanic rocks that consist of silicic domes and associated flows, pyroclastic rocks, and subvolcanic intrusions. The volcanic rocks were emplaced onto a basement of Mesozoic silicic intrusive rocks. A part of the Cactus Queen Mine is located on Federal land managed by the U.S. Bureau of Land Management (BLM). Staff from the BLM initially sampled the mine area and documented elevated concentrations of arsenic (As) in tailings and sediment. BLM then requested that the U.S. Geological Survey (USGS), in collaboration with Chapman University, measure and characterize As and other geochemical constituents in sediment, tailings, and waters on the part of the mine on Federal lands. This report is made in response to the request by the BLM, the lead agency mandated to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) - Removal Site Investigation (RSI). The RSI applies to the potential removal of As-contaminated mine waste from the Cactus Queen Mine as a means of reducing As release and exposure to humans and biota. This report summarizes data obtained from field sampling of sediments, mine tailings, and surface waters at the Cactus Queen Mine on January 27, 2008. Our results provide a preliminary assessment of the sources of As and associated chemical constituents that could potentially impact humans and biota.

  5. Synthesis of "cactus" top-decorated aligned carbon nanotubes and their third-order nonlinear optical properties.

    PubMed

    Li, P H; Qu, Y L; Xu, X J; Zhu, Y W; Yu, T; Chin, K C; Mi, J; Gao, X Y; Lim, C T; Shen, Z X; Wee, A T S; Ji, W; Sow, C H

    2006-04-01

    We report a new morphology of "cactus" top-decorated aligned carbon nanotubes grown by the PECVD method using pure C2H2 gas. Unlike most previous reports, no additional carrier gas is used for pretreatment. Carbon nanotubes can still grow and maintain the tubular structure underneath the "cactus" tops. It is proposed that the H atoms produced by the dissociation of C2H2 activate the catalyst nanoparticles. Scanning electron microscopy (SEM) shows that the top "cactus" morphology is composed of a large quantity of small nanosheets. Transmission electron microscopy (TEM) reveals the amorphous carbon nature of these "cactus" structures. The formation of these "cactus" structures is possibly due to covalent absorption and reconstruction of carbon atoms on the broken graphite layers of nanotubes produced by the strong ion bombardment under plasma. The third-order optical nonlinearities and nonlinear dynamics are also investigated. The third-order nonlinear susceptibility magnitude /chi(3)/ is found to be 2.2 x 10(-11) esu, and the relaxation process takes place in about 1.8 ps. PMID:16736755

  6. Growth of modern branched columnar stromatolites in Lake Joyce, Antarctica.

    PubMed

    Mackey, T J; Sumner, D Y; Hawes, I; Jungblut, A D; Andersen, D T

    2015-07-01

    Modern decimeter-scale columnar stromatolites from Lake Joyce, Antarctica, show a change in branching pattern during a period of lake level rise. Branching patterns correspond to a change in cyanobacterial community composition as preserved in authigenic calcite crystals. The transition in stromatolite morphology is preserved by mineralized layers that contain microfossils and cylindrical molds of cyanobacterial filaments. The molds are composed of two populations with different diameters. Large diameter molds (>2.8 μm) are abundant in calcite forming the oldest stromatolite layers, but are absent from younger layers. In contrast, <2.3 μm diameter molds are common in all stromatolites layers. Loss of large diameter molds corresponds to the transition from smooth-sided stromatolitic columns to branched and irregular columns. Mold diameters are similar to trichome diameters of the four most abundant living cyanobacteria morphotypes in Lake Joyce: Phormidium autumnale morphotypes have trichome diameters >3.5 μm, whereas Leptolyngbya antarctica, L. fragilis, and Pseudanabaena frigida morphotypes have diameters <2.3 μm. P. autumnale morphotypes were only common in mats at <12 m depth. Mats containing abundant P. autumnale morphotypes were smooth, whereas mats with few P. autumnale morphotypes contained small peaks and protruding bundles of filaments, suggesting that the absence of P. autumnale morphotypes allowed small-scale topography to develop on mats. Comparisons of living filaments and mold diameters suggest that P. autumnale morphotypes were present early in stromatolite growth, but disappeared from the community through time. We hypothesize that the mat-smoothing behavior of P. autumnale morphotypes inhibited nucleation of stromatolite branches. When P. autumnale morphotypes were excluded from the community, potentially reflecting a rise in lake level, short-wavelength roughness provided nuclei for stromatolite branches. This growth history provides a

  7. Modeling of current distribution on smooth and columnar platinum structures.

    PubMed

    Zinola, Carlos F

    2011-01-17

    Studying the growth and stability of anisotropic or isotropic disordered surfaces in electrodeposition is of importance in catalytic electrochemistry. In some cases, the metallic nature of the electrode defines the topography and roughness, which are also controlled by the experimental time and applied external potential. Because of the experimental restrictions in conventional electrochemical techniques and ex situ electron microscopies, a theoretical model of the surface geometry could aid in understanding the electrodeposition process and current distributions. In spite of applying a complex theory such as dynamic scaling method or perturbation theories, the resolution of mixed mass-/charge-transfer equations (tertiary distribution) for the electrodeposition process would give reliable information. One of the main problems with this type of distribution is the mathematics when solving the spatial n-dimensional differential equations. Use of a primary current distribution is proposed here to simplify the differential equations; however it limits wide application of the first assumption. Distributions of concentration profile, current density, and electrode potential are presented here as a function of the distance normal to the surface for the cases of smooth and rough platinum growth. In the particular case of columnar surfaces, cycloid curves are used to model the electrode, from which the concentration profile is presented in a parameterized form after solving a first-type curvilinear integral. The concentration contour results in a combination of a trigonometric inverse function and a linear distribution leading to a negative concavity curve. The calculation of the current density and electrode potential contours also show trigonometric shapes exhibiting forbidden imaginary values only at the minimal values of the trochoid curve.

  8. Feral livestock threatens landscapes dominated by columnar cacti

    NASA Astrophysics Data System (ADS)

    Malo, J. E.; Acebes, P.; Giannoni, S. M.; Traba, J.

    2011-05-01

    The introduction and naturalization of alien species represents a serious threat to many natural protected areas. One such case of worldwide concern is the impact of feral livestock on arid ecosystems. Damage suffered by Echinopsis (= Trichocereus) terscheckii dominating the landscape of rocky slopes was surveyed in seven locations within the Ischigualasto-Talampaya World Heritage Site (Argentina) by measuring the frequency, position on the plant and extent of damage. At the same time we employed transects to estimate the abundance of autochtonous and feral large herbivores ( Lama guanicoe, Bos taurus, Equus asinus) from their dung. Our results show relatively high damage levels (40-77% of individuals damaged, more than 5 dm 3 removed by plant in some sites), particularly within 0.50-1.75 m above the ground, showing herbivores to be the main responsible for them. We also found significant differences between sites in variables measuring damage level and in the intensity of use by the two feral livestock species but not by guanacos. The frequency of damaged cacti below 1.75 m (but not above) was significantly positively correlated among locations with the frequencies of cattle and donkey dung, and the damage suffered by individual cacti was also correlated with donkey and cattle dung in their surroundings after correcting for spatial effects. However, all correlations were non-significant in the case of guanacos. We conclude that the continued presence of feral livestock, particularly donkeys, leads to damages to columnar cacti with potential effects on their populations and the physiognomy of this protected landscape.

  9. Growth of modern branched columnar stromatolites in Lake Joyce, Antarctica.

    PubMed

    Mackey, T J; Sumner, D Y; Hawes, I; Jungblut, A D; Andersen, D T

    2015-07-01

    Modern decimeter-scale columnar stromatolites from Lake Joyce, Antarctica, show a change in branching pattern during a period of lake level rise. Branching patterns correspond to a change in cyanobacterial community composition as preserved in authigenic calcite crystals. The transition in stromatolite morphology is preserved by mineralized layers that contain microfossils and cylindrical molds of cyanobacterial filaments. The molds are composed of two populations with different diameters. Large diameter molds (>2.8 μm) are abundant in calcite forming the oldest stromatolite layers, but are absent from younger layers. In contrast, <2.3 μm diameter molds are common in all stromatolites layers. Loss of large diameter molds corresponds to the transition from smooth-sided stromatolitic columns to branched and irregular columns. Mold diameters are similar to trichome diameters of the four most abundant living cyanobacteria morphotypes in Lake Joyce: Phormidium autumnale morphotypes have trichome diameters >3.5 μm, whereas Leptolyngbya antarctica, L. fragilis, and Pseudanabaena frigida morphotypes have diameters <2.3 μm. P. autumnale morphotypes were only common in mats at <12 m depth. Mats containing abundant P. autumnale morphotypes were smooth, whereas mats with few P. autumnale morphotypes contained small peaks and protruding bundles of filaments, suggesting that the absence of P. autumnale morphotypes allowed small-scale topography to develop on mats. Comparisons of living filaments and mold diameters suggest that P. autumnale morphotypes were present early in stromatolite growth, but disappeared from the community through time. We hypothesize that the mat-smoothing behavior of P. autumnale morphotypes inhibited nucleation of stromatolite branches. When P. autumnale morphotypes were excluded from the community, potentially reflecting a rise in lake level, short-wavelength roughness provided nuclei for stromatolite branches. This growth history provides a

  10. Transition between columnar absorptive cells and goblet cells in the rat jejunal epithelium.

    PubMed

    Kurosumi, K; Shibuichi, I; Tosaka, H

    1981-11-01

    Electron microscopic observation of the jejunal epithelium of rats demonstrated morphological evidence of a transition between columnar absorptive cells and growing goblet cells. The columnar cells in both the villi and crypts have features suggestive of absorptive functions. They are provided with apical invaginations continuous to the intermicrovillous space. Absorbed lipid is observed in small vesicles in the terminal web layer, and chylomicrons derived here from are contained in large vacuoles near the Golgi apparatus. Ferritin particles artificially infused into the gut lumen were absorbed into the vacuoles in the subapical zone of columnar cells of suckling rats. Growing goblet cells situated in the crypt epithelium contain surface invaginations and lysosomes which are the same in structure as those found in absorptive cells nearby. Fat droplets evidently absorbed by the growing goblet cell were observed among immature mucus droplets. Artificially infused ferritin particles were found in vacuoles and lysosomes near the Golgi apparatus of some goblet cells of suckling rats. Some goblet cells on the intestinal villi of suckling rats looked immature and their microvilli and cytoplasmic matrix were clear like those of columnar absorptive cells. The transition between these goblet cells with clear cytoplasm and the mature goblet cells with dark cytoplasm was observed. These morphological evidences indicate that some of columnar cells already differentiated to absorptive cells are capable of transforming into mucus-producing (goblet) cells. It is suggested that not only undifferentiated columnar cells in the crypt base but also considerably differentiated columnar cells with absorptive function can differentiate into goblet cells. PMID:7325782

  11. Microbial populations and activities in the rhizoplane of rock-weathering desert plants. II. Growth promotion of cactus seedlings.

    PubMed

    Puente, M E; Li, C Y; Bashan, Y

    2004-09-01

    Four bacterial species isolated from the rhizoplane of cacti growing in bare lava rocks were assessed for growth promotion of giant cardon cactus seedlings (Pachycereus pringlei). These bacteria fixed N(2), dissolved P, weathered extrusive igneous rock, marble, and limestone, and significantly mobilized useful minerals, such as P, K, Mg, Mn, Fe, Cu, and Zn in rock minerals. Cardon cactus seeds inoculated with these bacteria were able to sprout and grow normally without added nutrients for at least 12 months in pulverized extrusive igneous rock (ancient lava flows) mixed with perlite. Cacti that were not inoculated grew less vigorously and some died. The amount of useful minerals (P, K, Fe, Mg) for plant growth extracted from the pulverized lava, measured after cultivation of inoculated plants, was significant. This study shows that rhizoplane bacteria isolated from rock-growing cacti promote growth of a cactus species, and can help supply essential minerals for a prolonged period of time.

  12. Microbial populations and activities in the rhizoplane of rock-weathering desert plants. II. Growth promotion of cactus seedlings.

    PubMed

    Puente, M E; Li, C Y; Bashan, Y

    2004-09-01

    Four bacterial species isolated from the rhizoplane of cacti growing in bare lava rocks were assessed for growth promotion of giant cardon cactus seedlings (Pachycereus pringlei). These bacteria fixed N(2), dissolved P, weathered extrusive igneous rock, marble, and limestone, and significantly mobilized useful minerals, such as P, K, Mg, Mn, Fe, Cu, and Zn in rock minerals. Cardon cactus seeds inoculated with these bacteria were able to sprout and grow normally without added nutrients for at least 12 months in pulverized extrusive igneous rock (ancient lava flows) mixed with perlite. Cacti that were not inoculated grew less vigorously and some died. The amount of useful minerals (P, K, Fe, Mg) for plant growth extracted from the pulverized lava, measured after cultivation of inoculated plants, was significant. This study shows that rhizoplane bacteria isolated from rock-growing cacti promote growth of a cactus species, and can help supply essential minerals for a prolonged period of time. PMID:15375736

  13. Validation of CME Detection Software (CACTus) by Means of Simulated Data, and Analysis of Projection Effects on CME Velocity Measurements

    NASA Astrophysics Data System (ADS)

    Bonte, K.; Jacobs, C.; Robbrecht, E.; de Groof, A.; Berghmans, D.; Poedts, S.

    2011-05-01

    In the context of space weather forecasting, an automated detection of coronal mass ejections (CMEs) becomes more and more important for efficiently handling a large data flow which is expected from recently-launched and future solar missions. In this paper we validate the detection software package "CACTus" by applying the program to synthetic data from our 3D time-dependent CME simulations instead of observational data. The main strength of this study is that we know in advance what should be detected. We describe the sensitivities and strengths of automated detection, more specific for the CACTus program, resulting in a better understanding of CME detection on one hand and the calibration of the CACTus software on the other hand, suggesting possible improvements of the package. In addition, the simulation is an ideal tool to investigate projection effects on CME velocity measurements.

  14. Relationship between columnar cell changes and low-grade carcinoma in situ of the breast--a cytogenetic study.

    PubMed

    Go, Edna May L; Tsang, Julia Y S; Ni, Yun-Bi; Yu, Alex M; Mendoza, Paulo; Chan, Siu-Ki; Lam, Christopher C; Lui, Philip C; Tan, Puay-Hoon; Tse, Gary M

    2012-11-01

    Columnar cell lesions of the breast include columnar cell changes without atypia and columnar cell changes with atypia. The latter frequently coexist and share molecular changes with low-grade carcinoma in situ and invasive carcinoma, suggesting that columnar cell changes may be precursors to progression of low-grade advanced lesions. In this study, we assessed chromosomal aberrations at 16q, hallmark for low-grade lesions, in columnar cell changes with or without atypia and their adjacent carcinoma in situ by fluorescent in situ hybridization using 3 region-specific probes spanning the entire chromosomal arm. The results were correlated with the histomorphological features of the corresponding lesions. Forty-four percent of low-grade carcinoma in situ and 31% of high-grade carcinoma in situ were associated with columnar cell changes with atypia, suggesting a link between columnar cell changes with atypia and low-grade carcinoma in situ. For the genetic aberrations, heterozygous deletion of 16q was present in 56% of low-grade carcinoma in situ but only in 19% of high-grade carcinoma in situ. Conversely, aneuploidy was found mostly in high-grade carcinoma in situ (88%). Twenty percent of columnar cell changes with atypia but none of the columnar cell changes without atypia showed heterozygous deletion of 16q. Interestingly, the same changes in 16q were observed in the columnar cell changes and their associated low-grade carcinoma in situ lesions. These findings demonstrated a genetic commonality between columnar cell changes with atypia and low-grade carcinoma in situ and substantiated the precursor role of columnar cell changes with atypia for low-grade carcinoma in situ but not high-grade carcinoma in situ of the breast.

  15. Microencapsulation of betalains obtained from cactus fruit (Opuntia ficus-indica) by spray drying using cactus cladode mucilage and maltodextrin as encapsulating agents.

    PubMed

    Otálora, María Carolina; Carriazo, José Gregorio; Iturriaga, Laura; Nazareno, Mónica Azucena; Osorio, Coralia

    2015-11-15

    The microencapsulation of betalains from cactus fruit by spray drying was evaluated as a stabilization strategy for these pigments. The betalains used as active agent were extracted from purple fruits of Opuntia ficus-indica (BE) and encapsulated with maltodextrin and cladode mucilage MD-CM and only with MD. The microcapsulates were characterized by scanning electron microscopy (SEM), thermal analysis (TGA-DSC), tristimulus colorimetry, as well as, their humidity, water activity and dietary fiber content were also determined. The active agent content was measured by UV-Vis spectrophotometry and its composition confirmed by HPLC-ESIMS. A pigment storage stability test was performed at 18 °C and different relative humidities. The addition of CM in the formulation increased the encapsulation efficiency, diminished the moisture content, and allowed to obtain more uniform size and spherical particles, with high dietary fiber content. These microencapsulates are promising functional additive to be used as natural colorant in the food industry. PMID:25977013

  16. Microencapsulation of betalains obtained from cactus fruit (Opuntia ficus-indica) by spray drying using cactus cladode mucilage and maltodextrin as encapsulating agents.

    PubMed

    Otálora, María Carolina; Carriazo, José Gregorio; Iturriaga, Laura; Nazareno, Mónica Azucena; Osorio, Coralia

    2015-11-15

    The microencapsulation of betalains from cactus fruit by spray drying was evaluated as a stabilization strategy for these pigments. The betalains used as active agent were extracted from purple fruits of Opuntia ficus-indica (BE) and encapsulated with maltodextrin and cladode mucilage MD-CM and only with MD. The microcapsulates were characterized by scanning electron microscopy (SEM), thermal analysis (TGA-DSC), tristimulus colorimetry, as well as, their humidity, water activity and dietary fiber content were also determined. The active agent content was measured by UV-Vis spectrophotometry and its composition confirmed by HPLC-ESIMS. A pigment storage stability test was performed at 18 °C and different relative humidities. The addition of CM in the formulation increased the encapsulation efficiency, diminished the moisture content, and allowed to obtain more uniform size and spherical particles, with high dietary fiber content. These microencapsulates are promising functional additive to be used as natural colorant in the food industry.

  17. Mechanical behavior and elastic properties of prestrained columnar ice

    NASA Astrophysics Data System (ADS)

    Snyder, Scott Aaron

    Experiments on columnar-grained ice at --10 °C reveal changes to its mechanical behavior and elastic properties due to compressive prestrain. Laboratory-grown (152-mm cube) specimens of freshwater and saline ice were prestrained under uniaxial across-column compression (to levels from epsilon p = 0.003 to epsilonp = 0.20, at constant strain rates in the ductile regime) and then reloaded, again under uniaxial across-column compression (at rates from 1x10--6 s--1 to 3 x 10--2s--1). Prestrain caused solid-state recrystallization as well as damage in the form of non-propagating microcracks. These microstructural changes were quantified by analysis of thin sections. Elastic properties in across-column directions, both parallel (x1) and perpendicular ( x2) to the initial loading direction, were obtained from P-wave and S-wave ultrasonic velocities. As a result (and depending on the level) of the prestrain imparted in both materials, Young's modulus E was reduced by as much as 30%; the ductile-to-brittle (D--B) transition strain rate epsilon D/B was increased up to a factor of 3 to 10; and the ductile behavior with respect to loading along a direction within the horizontal ( x1-x2) plane of the parent ice sheet changed from isotropic to anisotropic. As the prestrain rate approached the nominal D--B transition rate of initially undamaged material, the magnitudes of prestrain effects on elastic compliance increased. The shift in the D--B transition, on the other hand, was less sensitive to the prestrain rate. The results are interpreted within the framework of a recent model that predicts the transition strain rate based on the micromechanical boundary between creep and fracture processes. Prestrain primarily affected certain parameters in the model, specifically the power-law creep coefficient B (more so than the creep exponent n), Young's modulus E and, by extension, the fracture toughness KIc. The physical implications of these effects are discussed.

  18. Biofilm Formation by the Fish Pathogen Flavobacterium columnare: Development and Parameters Affecting Surface Attachment

    PubMed Central

    Cai, Wenlong; De La Fuente, Leonardo

    2013-01-01

    Flavobacterium columnare is a bacterial fish pathogen that affects many freshwater species worldwide. The natural reservoir of this pathogen is unknown, but its resilience in closed aquaculture systems posits biofilm as the source of contagion for farmed fish. The objectives of this study were (i) to characterize the dynamics of biofilm formation and morphology under static and flow conditions and (ii) to evaluate the effects of temperature, pH, salinity, hardness, and carbohydrates on biofilm formation. Nineteen F. columnare strains, including representatives of all of the defined genetic groups (genomovars), were compared in this study. The structure of biofilm was characterized by light microscopy, confocal laser scanning microscopy, and scanning electron microscopy. F. columnare was able to attach to and colonize inert surfaces by producing biofilm. Surface colonization started within 6 h postinoculation, and microcolonies were observed within 24 h. Extracellular polysaccharide substances and water channels were observed in mature biofilms (24 to 48 h). A similar time course was observed when F. columnare formed biofilm in microfluidic chambers under flow conditions. The virulence potential of biofilm was confirmed by cutaneous inoculation of channel catfish fingerlings with mature biofilm. Several physicochemical parameters modulate attachment to surfaces, with the largest influence being exerted by hardness, salinity, and the presence of mannose. Maintenance of hardness and salinity values within certain ranges could prevent biofilm formation by F. columnare in aquaculture systems. PMID:23851087

  19. The development of CACTUS : a wind and marine turbine performance simulation code.

    SciTech Connect

    Barone, Matthew Franklin; Murray, Jonathan

    2010-12-01

    CACTUS (Code for Axial and Cross-flow TUrbine Simulation) is a turbine performance simulation code, based on a free wake vortex method, under development at Sandia National Laboratories (SNL) as part of a Department of Energy program to study marine hydrokinetic (MHK) devices. The current effort builds upon work previously done at SNL in the area of vertical axis wind turbine simulation, and aims to add models to handle generic device geometry and physical models specific to the marine environment. An overview of the current state of the project and validation effort is provided.

  20. Increased acidification in the rhizosphere of cactus seedlings induced by Azospirillum brasilense

    NASA Astrophysics Data System (ADS)

    Carrillo, Angel; Li, Ching; Bashan, Yoav

    2002-08-01

    Acidification of the rhizosphere of cactus seedlings (giant cardon, Pachycereus pringlei) after inoculation with the plant growth-promoting bacterium Azospirillum brasilense Cd, in the presence or absence of ammonium and nitrate, was studied to understand how to increase growth of cardon seedlings in poor desert soils. While ammonium enhanced rhizosphere and liquid culture acidification, inoculation with the bacteria enhanced it further. On the other hand, nitrate increased pH of the rhizosphere, but combined with the bacterial inoculation, increase in pH was significantly smaller. Bacterial inoculation with ammonium enhanced plant growth.

  1. Sensitivity of bald eagle (Haliaeetus leucocephalus) hepatocyte cultures to induction of cytochrome P4501A by 2,3,7,8-tetrachlorodibenzo-p-dioxin.

    PubMed

    Kennedy, Sean W; Jones, Stephanie P; Elliott, John E

    2003-01-01

    Graded doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were added to primary hepatocyte cultures of bald eagle (Haliaeetus leucocephalus) embryos to determine their sensitivity to induction of cytochrome P4501A (CYP1A) and porphyrin accumulation. No porphyrin accumulation was observed, but both CYP1A catalytic activity (using the ethoxyresorufin-O-deethylase (EROD) assay) and immunodetectable CYP1A were induced by relatively high concentrations of TCDD. Bald eagle hepatocytes were less sensitive to CYP1A induction than hepatocytes from any other avian species that we have studied to date. These in vitro results are in general agreement with recent assessments of field data, which indicate that bald eagles are relatively insensitive to some of the effects of TCDD and related compounds. Preparation of bald eagle hepatocytes was challenging because existing methods did not yield monolayers of cells. Here we describe details of a new method that was successful for bald eagle hepatocytes. This new method is used routinely in our laboratory to prepare hepatocyte cultures from birds for examination of various biochemical responses to environmental contaminants.

  2. Morbidity and mortality of bald eagles (Haliaeetus leucocephalus) and peregrine falcons (Falco peregrinus) admitted to the Wildlife Center of Virginia, 1993-2003.

    PubMed

    Harris, M Camille; Sleeman, Jonathan M

    2007-03-01

    Medical records from 111 threatened bald eagles (86%, Haliaeetus leucocephalus) and peregrine falcons (14%, Falco peregrinus) admitted to the Wildlife Center of Virginia from 1993 to 2003 were reviewed to identify submitters, causes of morbidity and mortality, and final disposition. Half of all patients admitted were submitted by the Virginia Department of Game and Inland Fisheries personnel. Trauma was the most common reason for presentation in bald eagles (70%) and peregrine falcons (81%). Additional causes of morbidity and mortality in bald eagles included toxicoses (10%), infectious diseases (8%), and orphaned young (1%). Neoplasia was confirmed in two trauma cases, suggesting underlying disease might have increased susceptibility to acute traumatic injuries. Peregrine falcons were also admitted for infectious disease (19%). The most frequent infectious disease for both species was West Nile virus. Thirty-nine percent of patients were released back into the wild, 28% were euthanized, 20% died, and 13% were placed in captivity. Postrelease monitoring that would determine whether rehabilitated animals survived to contribute to threatened populations was not performed in this study.

  3. Moisture proof columnar Cesium Iodide (CsI) layers for gas avalanche microdetectors

    SciTech Connect

    Park, I.J.; Cho, H.S.; Hong, W.S.; Perez-Mendez, V.; Kadyk, J.

    1999-05-05

    Cesium iodide columnar layers having a diameter of 3 {micro}m, and wall spacing of {approx} 1 {micro}m act as secondary electron emitters and can be used for detection of radiation: charged particles, X-rays and gamma rays. With a large enough electric field across the columnar layers, {approx} 400 {micro}m in thickness, gas avalanche gain is evident when placed in a suitable gas, such as P10 or argon-ethane mixtures. The cesium iodide columns are damaged by ambient moisture. This damage can be prevented by evaporating protective layers of insoluble, low boiling point inorganic materials, such as mercuric iodide. Columnar layers with 20 nm coatings of mercuric iodide yield more than 30,000 electrons on average when traversed by electrons from a {sup 90}Sr beta source.

  4. A 3-phase model for mixed columnar-equiaxed solidification in DC casting of bronze

    NASA Astrophysics Data System (ADS)

    Hao, J.; Grasser, M.; Wu, M.; Ludwig, A.; Riedle, J.; Eberle, R.

    2012-01-01

    A three-phase Eulerian approach is used to model the columnar-to-equiaxed transition (CET) during solidification in DC casting of technical bronze. The three phases are the melt, the solidifying columnar dendrites and the equiaxed grains. They are considered as spatially interpenetrating and interacting continua by solving the conservation equations of mass, momentum, species and enthalpy for all three phases. The so defined solidification model is applied to a binary CuSn6 DC casting process as a benchmark to demonstrate the model potentials. Two cases are studied: one considering only feeding flow and one including both feeding flow and equiaxed sedimentation. The simulated results of mixed columnar and equiaxed solidification are presented and discussed including the occurrence of CET, phase distribution, feeding flow, equiaxed sedimentation and their influence on macrosegregation.

  5. Columnar transmitter based wireless power delivery system for implantable device in freely moving animals.

    PubMed

    Eom, Kyungsik; Jeong, Joonsoo; Lee, Tae Hyung; Lee, Sung Eun; Jun, Sang Bum; Kim, Sung June

    2013-01-01

    A wireless power delivery system is developed to deliver electrical power to the neuroprosthetic devices that are implanted into animals freely moving inside the cage. The wireless powering cage is designed for long-term animal experiments without cumbersome wires for power supply or the replacement of batteries. In the present study, we propose a novel wireless power transmission system using resonator-based inductive links to increase power efficiency and to minimize the efficiency variations. A columnar transmitter coil is proposed to provide lateral uniformity of power efficiency. Using this columnar transmitter coil, only 7.2% efficiency fluctuation occurs from the maximum transmission efficiency of 25.9%. A flexible polymer-based planar type receiver coil is fabricated and assembled with a neural stimulator and an electrode. Using the designed columnar transmitter coil, the implantable device successfully operates while it moves freely inside the cage. PMID:24110073

  6. ISS-Experiments of Columnar-to-Equiaxed Transition in Solidification Processing

    NASA Technical Reports Server (NTRS)

    Sturz, Laszlo; Zimmermann, Gerhard; Gandin, Charles, Andre; Billia, Bernard; Magelinck, Nathalie; Nguyen-Thi, Henry; Browne, David John; Mirihanage, Wajira U.; Voss, Daniela; Beckermann, Christoph; Karma, Alain

    2012-01-01

    The main topic of the research project CETSOL in the framework of the Microgravity Application Promotion (MAP) programme of the European Space Agency (ESA) is the investigation of the transition from columnar to equiaxed grain growth during solidification. Microgravity environment allows for suppression of buoyancy-driven melt flow and for growth of equiaxed grains free of sedimentation and buoyancy effects. This contribution will present first experimental results obtained in microgravity using hypo-eutectic AlSi alloys in the Materials Science Laboratory (MSL) on-board the International Space Station (ISS). The analysis of the experiments confirms the existence of a columnar to equiaxed transition, especially in the refined alloy. Temperature evolution and grain structure analysis provide critical values for the position, the temperature gradient and the solidification velocity at the columnar to equiaxed transition. These data will be used to improve modeling of solidification microstructures and grain structure on different lengths scales.

  7. Examination of tissue distribution of Helicobacter pylori within columnar-lined esophagus.

    PubMed

    Sharma, V K; Demian, S E; Taillon, D; Vasudeva, R; Howden, C W

    1999-06-01

    H. pylori may colonize columnar-lined esophagus, although an etiologic role in esophageal adenocarcinoma is unproven. H. pylori can adhere to intestinal metaplasia in the stomach. This study was designed to examine if H. pylori adheres to specialized intestinal metaplasia in columnar-lined esophagus. Esophageal biopsies from patients with columnar-lined esophagus were reviewed. Patients with only gastric metaplasia were excluded. Sections with specialized intestinal metaplasia in at least one third of at least one gland were recut, stained using the Giemsa stain, and reexamined by two independent pathologists using strict criteria for adherence by H. pylori. The 209 esophageal biopsies with adequate specialized intestinal metaplasia from 58 patients were examined: H. pylori was only seen on gastric metaplasia in three patients-and never on specialized intestinal metaplasia. Within the esophagus, H. pylori adheres only to gastric metaplasia, which is not considered premalignant for esophageal adenocarcinoma. PMID:10389690

  8. A theoretical study of CsI:Tl columnar scintillator image quality parameters by analytical modeling

    NASA Astrophysics Data System (ADS)

    Kalyvas, N.; Valais, I.; Michail, C.; Fountos, G.; Kandarakis, I.; Cavouras, D.

    2015-04-01

    Medical X-ray digital imaging systems such as mammography, radiography and computed tomography (CT), are composed from efficient radiation detectors, which can transform the X-rays to electron signal. Scintillators are materials that emit light when excited by X-rays and incorporated in X-ray medical imaging detectors. Columnar scintillator, like CsI:T1 is very often used for X-ray detection due to its higher performance. The columnar form limits the lateral spread of the optical photons to the scintillator output, thus it demonstrates superior spatial resolution compared to granular scintillators. The aim of this work is to provide an analytical model for calculating the MTF, the DQE and the emission efficiency of a columnar scintillator. The model parameters were validated against published Monte Carlo data. The model was able to predict the overall performance of CsI:Tl scintillators and suggested an optimum thickness of 300 μm for radiography applications.

  9. Columnar discharge mode between parallel dielectric barrier electrodes in atmospheric pressure helium

    SciTech Connect

    Hao, Yanpeng; Zheng, Bin; Liu, Yaoge

    2014-01-15

    Using a fast-gated intensified charge-coupled device, end- and side-view photographs were taken of columnar discharge between parallel dielectric barrier electrodes in atmospheric pressure helium. Based on three-dimensional images generated from end-view photographs, the number of discharge columns increased, whereas the diameter of each column decreased as the applied voltage was increased. Side-view photographs indicate that columnar discharges exhibited a mode transition ranging from Townsend to glow discharges generated by the same discharge physics as atmospheric pressure glow discharge.

  10. A Combined Study of Mesomorphism, Optical and Electronic Properties of Novel Columnar Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Chen, Shuai

    Columnar mesophases of discotic liquid crystals (DLCs) are a separate class of organic semiconductors. Anisotropic charge transport, high charge carrier mobility, and self-organizing properties have been regarded as superior properties of DLCs but their performance in devices, such as organic light-emitting diodes, has been inferior to the best performing conventional organic semiconductors. Our group recently demonstrated that a DLC of donor-acceptor structure can bias electron over hole conduction if the occupied and unoccupied frontier orbitals are localized on different parts of the molecule and only the unoccupied frontier orbitals electronically interact in columnar stacks. This thesis describes the first systematic approach to different types of donor-acceptor DLCs and the investigation of their mesomorphism and optoelectronic properties. In spite of their large aspect ratios, four board-shaped donor-acceptor-donor quinoxalinophenanthrophenazine (QPP) dyes (Chapters 2 and 3) induce complex columnar mesomorphism over wide temperature ranges. These QPP derivatives also show strong fluorescence in solution and as thin films. This strong fluorescence in columnar mesophases is explained with a nonparallel orientation of the elongated donor-acceptor cores in the columnar stacks that minimizes interactions between transition dipole moments of co-facially stacked molecules. Opto-electronic properties suggest that the QPP derivatives are organic semiconductors. Inspired by the donor-acceptor concept, we generated novel ionic DLCs based on imidazole and imidazolium structures (Chapter 5). Unexpectedly, only the ionic triphenylenoimidazolium derivatives display columnar mesomorphism. Strong ionic interactions between the cores are apparently required for the formation of columnar mesophases. Overall, these compounds are rather unusual because few ionic DLCs have the charge localized on the aromatic core. Most often the charged group is attached via spacer chains. A

  11. Does flat epithelial atypia have rounder nuclei than columnar cell change/hyperplasia? A morphometric approach to columnar cell lesions of the breast.

    PubMed

    Yamashita, Yoshiko; Ichihara, Shu; Moritani, Suzuko; Yoon, Han-Seung; Yamaguchi, Masahiro

    2016-06-01

    Columnar cell lesions of the breast encompass columnar cell change/hyperplasia (CCC/CCH) and flat epithelial atypia (FEA). These have attracted researchers because emerging data suggest that FEA may represent the earliest histologically detectable non-obligate precursor of breast cancer. However, it is occasionally difficult to distinguish FEA from CCC/CCH because of similar histology. Although the nuclei of FEA are frequently described as relatively round compared with those of CCC/CCH, there are few morphometric studies to support this statement. The aim of this study was to provide objective data as to the nuclear shape in columnar cell lesions. As a shape descriptor, we adopted ellipticity that is defined by the formula 2b/2a, where a is the length of the long axis of the ellipse and b is the length of the short axis. Contrary to circularity, ellipticity reflects the overall configuration of an ellipse irrespective of surface irregularity. Our image analysis included generating whole slide images, extracting glandular cell nuclei, measuring nuclear ellipticity, and superimposing graded colors based on execution of results on the captured images. A total of 7917 nuclei extracted from 22 FEA images and 5010 nuclei extracted from 13 CCC/CCH images were analyzed. There was a significant difference in nuclear roundness between FEA and CCC/CCH with mean ellipticity values of 0.723 and 0.679, respectively (p < 0.001, Welch's t test). Furthermore, FEA with malignancy had significantly rounder nuclei than FEA without malignancy (p < 0.001). Our preliminary results suggest that nuclear ellipticity is a key parameter in reproducibly classifying columnar cell lesions of the breast.

  12. Effective directional self-gathering of drops on spine of cactus with splayed capillary arrays

    PubMed Central

    Liu, Chengcheng; Xue, Yan; Chen, Yuan; Zheng, Yongmei

    2015-01-01

    We report that the fast droplet transport without additional energy expenditure can be achieved on the spine of cactus (Gymnocalycium baldianum) with the assistance of its special surface structure: the cactus spine exhibits a cone-like structure covered with tilted scales. A single scale and the spine surface under it cooperatively construct a splayed capillary tube. The arrays of capillary tube formed by the overlapping scales build up the out layer of the spine. The serial drops would be driven by the asymmetric structure resulted from tilt-up scales-by-scales on the cone-shaped spine, and move directionally toward the bottom from top of spine, by means of the Laplace pressure in differences. In addition, after the past of the first droplet, thin liquid film of drop is trapped in the splayed capillary micro-tube on the surface of spine, which greatly reduces the friction of subsequential droplet transport in efficiency. This finding provides a new biological model which could be used to transport droplet spontaneously and directionally. Also this work offers a way to reduce the surface adhesion by constructing liquid film on the surface, which has great significance in prompting droplet transport efficiency. PMID:26639758

  13. Phylogeography of the Cactophilic Drosophila and Other Arthropods Associated with Cactus Necroses in the Sonoran Desert

    PubMed Central

    Pfeiler, Edward; Markow, Therese A.

    2011-01-01

    Studies on the population genetics, phylogenetic relationships, systematics and evolution of arthropods that inhabit necrotic tissue of cacti in the Sonoran Desert of North America are reviewed. These studies have focused upon several species of insects (orders Diptera and Coleoptera) and arachnids (order Pseudoscorpiones). For most taxa studied, little genetic structure and high dispersal ability are found in populations inhabiting the mainland and Baja California peninsula regions of the Sonoran Desert, consistent with the availability of the rotting cactus microhabitat which is patchily distributed and ephemeral. There is evidence, however, that the Gulf of California, which bisects the Sonoran Desert, has played a role in limiting gene flow and promoting speciation in several taxa, including histerid beetles, whereas other taxa, especially Drosophila nigrospiracula and D. mettleri, apparently are able to freely cross the Gulf, probably by taking advantage of the Midriff Islands in the northern Gulf as dispersal “stepping stones”. Genetic evidence has also been found for historical population expansions dating to the Pleistocene and late Pliocene in several taxa. Overall, these studies have provided important insights into how arthropods with different life history traits, but generally restricted to a necrotic cactus microhabitat, have evolved in an environmentally harsh and tectonically active region. In addition, they suggest some taxa for further, and more detailed, hypothesis driven studies of speciation. PMID:26467624

  14. Antibacterial and antioxidant activities in extracts of fully grown cladodes of 8 cultivars of cactus pear.

    PubMed

    Sánchez, E; Dávila-Aviña, J; Castillo, S L; Heredia, N; Vázquez-Alvarado, R; García, S

    2014-04-01

    The antimicrobial and antioxidant activities of some cultivars of the nopal cactus have not been determined. In this study, 8 cultivars of nopal cacti from Mexico were assayed for phenolic content, antioxidant activities, and antimicrobial activities against Campylobacter Jejuni, Vibrio cholera, and Clostridium Perfringens. Plant material was washed, dried, and macerated in methanol. Minimum bactericidal concentrations (MBCs) were determined using the broth microdilution method. Antioxidant activities were quantitatively determined using spectrophotometric methods. The MCBs of the nopal cacti ranged from 1.1 to 12.5 mg/mL for c. jejuni, 4.4 to 30 mg/mL for V. cholera, and 0.8 to 16 mg/mL for C. perfringens in the cultivars Cardon Blanco, Real de Catorce, and Jalpa, respectively. High quantities of total phenols and total flavonoids were found in the Jalpa cacti (3.80 mg of gallic acid equivalent GAE/g dry weight [DW] and 36.64 mg of quercetin equivalents [QE]/g DW, respectively). 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities (RSA) were correlated to bioactive compound contents. The Villanueva cacti had the highest %RSA at 42.31%, and the lowest activity was recorded in Copena V1 at 19.98%. In conclusion, we found that some of the 8 cactus pear cultivars studied may be used for their antioxidant compounds or antimicrobials to control or prevent the contamination of foods. PMID:24621296

  15. Effective directional self-gathering of drops on spine of cactus with splayed capillary arrays.

    PubMed

    Liu, Chengcheng; Xue, Yan; Chen, Yuan; Zheng, Yongmei

    2015-12-07

    We report that the fast droplet transport without additional energy expenditure can be achieved on the spine of cactus (Gymnocalycium baldianum) with the assistance of its special surface structure: the cactus spine exhibits a cone-like structure covered with tilted scales. A single scale and the spine surface under it cooperatively construct a splayed capillary tube. The arrays of capillary tube formed by the overlapping scales build up the out layer of the spine. The serial drops would be driven by the asymmetric structure resulted from tilt-up scales-by-scales on the cone-shaped spine, and move directionally toward the bottom from top of spine, by means of the Laplace pressure in differences. In addition, after the past of the first droplet, thin liquid film of drop is trapped in the splayed capillary micro-tube on the surface of spine, which greatly reduces the friction of subsequential droplet transport in efficiency. This finding provides a new biological model which could be used to transport droplet spontaneously and directionally. Also this work offers a way to reduce the surface adhesion by constructing liquid film on the surface, which has great significance in prompting droplet transport efficiency.

  16. Factors affecting establishment success of the endangered Caribbean cactus Harrisia portoricensis (Cactaceae).

    PubMed

    Rojas-Sandoval, Julissa; Meléndez-Ackerman, Elvia

    2012-06-01

    Early plant stages may be the most vulnerable within the life cycle of plants especially in arid ecosystems. Interference from exotic species may exacerbate this condition. We evaluated germination, seedling survival and growth in the endangered Caribbean cactus Harrisia portoricensis, as a function of sunlight exposure (i.e., growing under open and shaded areas), different shade providers (i.e., growing under two native shrubs and one exotic grass species), two levels of predation (i.e., exclusion and non-exclusion) and variable microenvironmental conditions (i.e., temperature, PAR, humidity). Field experiments demonstrated that suitable conditions for germination and establishment of H. portoricensis seedling are optimal in shaded areas beneath the canopy of established species, but experiments also demonstrated that the identity of the shade provider can have a significant influence on the outcome of these processes. Harrisia portoricensis seedlings had higher probabilities of survival and grew better (i.e., larger diameters) when they were transplanted beneath the canopy of native shrubs, than beneath the exotic grass species, where temperature and solar radiation values were on average much higher than those obtained under the canopies of native shrubs. We also detected that exclusion from potential predators did not increase seedling survival. Our combined results for H. portoricensis suggested that the modification of microenvironmental conditions by the exotic grass may lower the probability of recruitment and establishment of this endangered cactus species.

  17. The cactus worm : experiments with dynamic resource discovery and allocation in a grid environment.

    SciTech Connect

    Allen, G.; Angulo, D.; Foster, I.; Lanfermann, G.; Liu, C.; Radke, T.; Seidel, E.; Shalf, J.; Mathematics and Computer Science; Albert-Einstein-Inst.; Univ. of Chicago; LBNL

    2001-01-01

    The ability to harness heterogeneous, dynamically available grid resources is attractive to typically resource-starved computational scientists and engineers, as in principle it can increase, by significant factors, the number of cycles that can be delivered to applications. However, new adaptive application structures and dynamic runtime system mechanisms are required if we are to operate effectively in grid environments. To explore some of these issues in a practical setting, the authors are developing an experimental framework, called Cactus, that incorporates both adaptive application structures for dealing with changing resource characteristics and adaptive resource selection mechanisms that allow applications to change their resource allocations (e.g., via migration) when performance falls outside specified limits. The authors describe the adaptive resource selection mechanisms and describe how they are used to achieve automatic application migration to 'better' resources following performance degradation. The results provide insights into the architectural structures required to support adaptive resource selection. In addition, the authors suggest that the Cactus Worm affords many opportunities for grid computing.

  18. Not all the infected develop the disease - A "Lotus and Cactus" model.

    PubMed

    Pitchappan, Ramasamy M

    2016-06-01

    The immunogenetic dictum "not all the infected develop the disease" can best be explained by a "Lotus and Cactus" model. Lotuses grow in ponds and cacti in deserts: analogously, we can say that tubercle patient's lung (genetic makeup) functions as an ideal 'broth' for Mycobacterium tuberculosis (M.tb) germs to grow, but not the lungs of an endemic control. HLA association studies from Europe to Asia since 1983 till date, have shown a persistent HLA DR2 (15) association. Further, HLA DR2 and non-DR2 endemic controls showed disparate patterns of immune responses and gene expressions. The host and pathogen MHC diversities, Th1-Th2 paradigm and cytokine circuits all may play a crucial role in TB susceptibility. It is possible to decipher the protective immunity by controlling the known confounders - epidemiological, demographic, socio-biological and also host and pathogen diversities. This has become significant with our understanding on the 'out of Africa' migration and neolithic co-dispersal of M.tb with modern human. Divergence and expansion of various MHCs (eg HLA-DRB1*15, HLA-B*57) and non-MHC alleles in various continents might be responsible for the skewed transmission and distribution of the infectious diseases around the globe. The 'Lotus and Cactus' model proposed here exemplifies this. A holistic genetic epidemiology approach employing modern tools is the need of the hour to better understand infectious disease susceptibility.

  19. Influence of abscisic acid and sucrose on somatic embryogenesis in Cactus Copiapoa tenuissima Ritt. forma mostruosa.

    PubMed

    Lema-Rumińska, J; Goncerzewicz, K; Gabriel, M

    2013-01-01

    Having produced the embryos of cactus Copiapoa tenuissima Ritt. forma monstruosa at the globular stage and callus, we investigated the effect of abscisic acid (ABA) in the following concentrations: 0, 0.1, 1, 10, and 100  μ M on successive stages of direct (DSE) and indirect somatic embryogenesis (ISE). In the indirect somatic embryogenesis process we also investigated a combined effect of ABA (0, 0.1, 1  μ M) and sucrose (1, 3, 5%). The results showed that a low concentration of ABA (0-1  μ M) stimulates the elongation of embryos at the globular stage and the number of correct embryos in direct somatic embryogenesis, while a high ABA concentration (10-100  μ M) results in growth inhibition and turgor pressure loss of somatic embryos. The indirect somatic embryogenesis study in this cactus suggests that lower ABA concentrations enhance the increase in calli fresh weight, while a high concentration of 10  μ M ABA or more changes calli color and decreases its proliferation rate. However, in the case of indirect somatic embryogenesis, ABA had no effect on the number of somatic embryos and their maturation. Nevertheless, we found a positive effect of sucrose concentration for both the number of somatic embryos and the increase in calli fresh weight.

  20. Effective directional self-gathering of drops on spine of cactus with splayed capillary arrays

    NASA Astrophysics Data System (ADS)

    Liu, Chengcheng; Xue, Yan; Chen, Yuan; Zheng, Yongmei

    2015-12-01

    We report that the fast droplet transport without additional energy expenditure can be achieved on the spine of cactus (Gymnocalycium baldianum) with the assistance of its special surface structure: the cactus spine exhibits a cone-like structure covered with tilted scales. A single scale and the spine surface under it cooperatively construct a splayed capillary tube. The arrays of capillary tube formed by the overlapping scales build up the out layer of the spine. The serial drops would be driven by the asymmetric structure resulted from tilt-up scales-by-scales on the cone-shaped spine, and move directionally toward the bottom from top of spine, by means of the Laplace pressure in differences. In addition, after the past of the first droplet, thin liquid film of drop is trapped in the splayed capillary micro-tube on the surface of spine, which greatly reduces the friction of subsequential droplet transport in efficiency. This finding provides a new biological model which could be used to transport droplet spontaneously and directionally. Also this work offers a way to reduce the surface adhesion by constructing liquid film on the surface, which has great significance in prompting droplet transport efficiency.

  1. Intake, performance, and carcass characteristics of lambs fed spineless cactus replacing wheat bran.

    PubMed

    Felix, Sabrina Carla Rodrigues; Pessoa, Ricardo Alexandre Silva; Ferreira, Marcelo de Andrade; Soares, Luciana Felizardo Pereira; Silva, Janaina de Lima; de Abreu, Karen Santos Felix; de Melo, Ana Caroline Cerqueira

    2016-02-01

    To assess the intake, digestibility of nutrients, ingestive behavior, performance, and carcass characteristics of feedlot lambs, 36 F1 Santa Ines × Dorper male lambs with an initial average weight of 19.5 ± 0.27 kg were fed with different levels of spineless cactus (0, 33, 66, and 100 %) as a replacement of the wheat bran. The replacement diets had no effect on the intake of dry matter (DM) or crude protein (CP), whose average values were 962 and 140 g/day, respectively. There was a quadratic effect on the intake of digestible organic matter (OM) and the digestibility of DM, CP, neutral detergent fiber (NDF), and non-fiber carbohydrates (NFC). The highest average daily gain (ADG) of 168 g/day was achieved at 58.7 % replacement level. The highest hot and cold carcass weights of 15.4 and 14.5 kg were achieved at 62.4 and 56.9 % replacement levels. For lambs in the feedlot, we recommend replacing wheat bran with up to 58.7 % spineless cactus.

  2. Not all the infected develop the disease - A "Lotus and Cactus" model.

    PubMed

    Pitchappan, Ramasamy M

    2016-06-01

    The immunogenetic dictum "not all the infected develop the disease" can best be explained by a "Lotus and Cactus" model. Lotuses grow in ponds and cacti in deserts: analogously, we can say that tubercle patient's lung (genetic makeup) functions as an ideal 'broth' for Mycobacterium tuberculosis (M.tb) germs to grow, but not the lungs of an endemic control. HLA association studies from Europe to Asia since 1983 till date, have shown a persistent HLA DR2 (15) association. Further, HLA DR2 and non-DR2 endemic controls showed disparate patterns of immune responses and gene expressions. The host and pathogen MHC diversities, Th1-Th2 paradigm and cytokine circuits all may play a crucial role in TB susceptibility. It is possible to decipher the protective immunity by controlling the known confounders - epidemiological, demographic, socio-biological and also host and pathogen diversities. This has become significant with our understanding on the 'out of Africa' migration and neolithic co-dispersal of M.tb with modern human. Divergence and expansion of various MHCs (eg HLA-DRB1*15, HLA-B*57) and non-MHC alleles in various continents might be responsible for the skewed transmission and distribution of the infectious diseases around the globe. The 'Lotus and Cactus' model proposed here exemplifies this. A holistic genetic epidemiology approach employing modern tools is the need of the hour to better understand infectious disease susceptibility. PMID:26611827

  3. Effective directional self-gathering of drops on spine of cactus with splayed capillary arrays.

    PubMed

    Liu, Chengcheng; Xue, Yan; Chen, Yuan; Zheng, Yongmei

    2015-01-01

    We report that the fast droplet transport without additional energy expenditure can be achieved on the spine of cactus (Gymnocalycium baldianum) with the assistance of its special surface structure: the cactus spine exhibits a cone-like structure covered with tilted scales. A single scale and the spine surface under it cooperatively construct a splayed capillary tube. The arrays of capillary tube formed by the overlapping scales build up the out layer of the spine. The serial drops would be driven by the asymmetric structure resulted from tilt-up scales-by-scales on the cone-shaped spine, and move directionally toward the bottom from top of spine, by means of the Laplace pressure in differences. In addition, after the past of the first droplet, thin liquid film of drop is trapped in the splayed capillary micro-tube on the surface of spine, which greatly reduces the friction of subsequential droplet transport in efficiency. This finding provides a new biological model which could be used to transport droplet spontaneously and directionally. Also this work offers a way to reduce the surface adhesion by constructing liquid film on the surface, which has great significance in prompting droplet transport efficiency. PMID:26639758

  4. Intake, performance, and carcass characteristics of lambs fed spineless cactus replacing wheat bran.

    PubMed

    Felix, Sabrina Carla Rodrigues; Pessoa, Ricardo Alexandre Silva; Ferreira, Marcelo de Andrade; Soares, Luciana Felizardo Pereira; Silva, Janaina de Lima; de Abreu, Karen Santos Felix; de Melo, Ana Caroline Cerqueira

    2016-02-01

    To assess the intake, digestibility of nutrients, ingestive behavior, performance, and carcass characteristics of feedlot lambs, 36 F1 Santa Ines × Dorper male lambs with an initial average weight of 19.5 ± 0.27 kg were fed with different levels of spineless cactus (0, 33, 66, and 100 %) as a replacement of the wheat bran. The replacement diets had no effect on the intake of dry matter (DM) or crude protein (CP), whose average values were 962 and 140 g/day, respectively. There was a quadratic effect on the intake of digestible organic matter (OM) and the digestibility of DM, CP, neutral detergent fiber (NDF), and non-fiber carbohydrates (NFC). The highest average daily gain (ADG) of 168 g/day was achieved at 58.7 % replacement level. The highest hot and cold carcass weights of 15.4 and 14.5 kg were achieved at 62.4 and 56.9 % replacement levels. For lambs in the feedlot, we recommend replacing wheat bran with up to 58.7 % spineless cactus. PMID:26676244

  5. Influence of Abscisic Acid and Sucrose on Somatic Embryogenesis in Cactus Copiapoa tenuissima Ritt. forma mostruosa

    PubMed Central

    Lema-Rumińska, J.; Goncerzewicz, K.; Gabriel, M.

    2013-01-01

    Having produced the embryos of cactus Copiapoa tenuissima Ritt. forma monstruosa at the globular stage and callus, we investigated the effect of abscisic acid (ABA) in the following concentrations: 0, 0.1, 1, 10, and 100 μM on successive stages of direct (DSE) and indirect somatic embryogenesis (ISE). In the indirect somatic embryogenesis process we also investigated a combined effect of ABA (0, 0.1, 1 μM) and sucrose (1, 3, 5%). The results showed that a low concentration of ABA (0-1 μM) stimulates the elongation of embryos at the globular stage and the number of correct embryos in direct somatic embryogenesis, while a high ABA concentration (10–100 μM) results in growth inhibition and turgor pressure loss of somatic embryos. The indirect somatic embryogenesis study in this cactus suggests that lower ABA concentrations enhance the increase in calli fresh weight, while a high concentration of 10 μM ABA or more changes calli color and decreases its proliferation rate. However, in the case of indirect somatic embryogenesis, ABA had no effect on the number of somatic embryos and their maturation. Nevertheless, we found a positive effect of sucrose concentration for both the number of somatic embryos and the increase in calli fresh weight. PMID:23843737

  6. Marketability of ready-to-eat cactus pear as affected by temperature and modified atmosphere.

    PubMed

    Cefola, Maria; Renna, Massimiliano; Pace, Bernardo

    2014-01-01

    In order to increase the diffusion of cactus pear fruits, in this study, the proper maturity index for peeling and processing them as ready-to-eat product was evaluated and characterized. Thereafter, the effects of different storage temperatures and modified atmosphere conditions on the marketability of ready-to-eat cactus pear were studied. The storage of ready-to-eat fruits at 4 °C in both passive (air) and semi-active (10 kPa O2 and 10 kPa CO2) modified atmosphere improved the marketability by 30%, whereas the storage at 8 °C caused a dangerous reduction in O2 partial pressure inside modified atmosphere packages, due to fruits' increased metabolic activity. A very low level of initial microbial growth was detected, while a severe increase in mesophilic and psychrophilic bacteria was shown in control samples at both temperatures during storage; an inhibitory effect of modified atmosphere on microbial growth was also observed. In conclusion, modified atmosphere improved only the marketability of fruits stored at 4 °C; whereas the storage at 8 °C resulted in deleterious effects on the ready-to-eat fruits, whether stored in air or in modified atmosphere.

  7. Effect of extrusion cooking on bioactive compounds in encapsulated red cactus pear powder.

    PubMed

    Ruiz-Gutiérrez, Martha G; Amaya-Guerra, Carlos A; Quintero-Ramos, Armando; Pérez-Carrillo, Esther; Ruiz-Anchondo, Teresita de J; Báez-González, Juan G; Meléndez-Pizarro, Carmen O

    2015-05-18

    Red cactus pear has significant antioxidant activity and potential as a colorant in food, due to the presence of betalains. However, the betalains are highly thermolabile, and their application in thermal process, as extrusion cooking, should be evaluated. The aim of this study was to evaluate the effect of extrusion conditions on the chemical components of red cactus pear encapsulated powder. Cornstarch and encapsulated powder (2.5% w/w) were mixed and processed by extrusion at different barrel temperatures (80, 100, 120, 140 °C) and screw speeds (225, 275, 325 rpm) using a twin-screw extruder. Mean residence time (trm), color (L*, a*, b*), antioxidant activity, total polyphenol, betacyanin, and betaxanthin contents were determined on extrudates, and pigment degradation reaction rate constants (k) and activation energies (Ea) were calculated. Increases in barrel temperature and screw speed decreased the trm, and this was associated with better retentions of antioxidant activity, total polyphenol, betalain contents. The betacyanins k values ranged the -0.0188 to -0.0206/s and for betaxanthins ranged of -0.0122 to -0.0167/s, while Ea values were 1.5888 to 6.1815 kJ/mol, respectively. The bioactive compounds retention suggests that encapsulated powder can be used as pigments and to provide antioxidant properties to extruded products.

  8. Betalains, Phenols and Antioxidant Capacity in Cactus Pear [Opuntia ficus-indica (L.) Mill.] Fruits from Apulia (South Italy) Genotypes.

    PubMed

    Albano, Clara; Negro, Carmine; Tommasi, Noemi; Gerardi, Carmela; Mita, Giovanni; Miceli, Antonio; De Bellis, Luigi; Blando, Federica

    2015-01-01

    Betacyanin (betanin), total phenolics, vitamin C and antioxidant capacity (by Trolox-equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays) were investigated in two differently colored cactus pear (Opuntia ficus-indica (L.) Mill.) genotypes, one with purple fruit and the other with orange fruit, from the Salento area, in Apulia (South Italy). In order to quantitate betanin in cactus pear fruit extracts (which is difficult by HPLC because of the presence of two isomers, betanin and isobetanin, and the lack of commercial standard with high purity), betanin was purified from Amaranthus retroflexus inflorescence, characterized by the presence of a single isomer. The purple cactus pear variety showed very high betanin content, with higher levels of phenolics, vitamin C, and antioxidant capacity (TEAC) than the orange variety. These findings confirm the potential for exploiting the autochthonous biodiversity of cactus pear fruits. In particular, the purple variety could be an interesting source of colored bioactive compounds which not only have coloring potential, but are also an excellent source of dietary antioxidant components which may have beneficial effects on consumers' health. PMID:26783704

  9. Betalains, Phenols and Antioxidant Capacity in Cactus Pear [Opuntia ficus-indica (L.) Mill.] Fruits from Apulia (South Italy) Genotypes.

    PubMed

    Albano, Clara; Negro, Carmine; Tommasi, Noemi; Gerardi, Carmela; Mita, Giovanni; Miceli, Antonio; De Bellis, Luigi; Blando, Federica

    2015-04-01

    Betacyanin (betanin), total phenolics, vitamin C and antioxidant capacity (by Trolox-equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays) were investigated in two differently colored cactus pear (Opuntia ficus-indica (L.) Mill.) genotypes, one with purple fruit and the other with orange fruit, from the Salento area, in Apulia (South Italy). In order to quantitate betanin in cactus pear fruit extracts (which is difficult by HPLC because of the presence of two isomers, betanin and isobetanin, and the lack of commercial standard with high purity), betanin was purified from Amaranthus retroflexus inflorescence, characterized by the presence of a single isomer. The purple cactus pear variety showed very high betanin content, with higher levels of phenolics, vitamin C, and antioxidant capacity (TEAC) than the orange variety. These findings confirm the potential for exploiting the autochthonous biodiversity of cactus pear fruits. In particular, the purple variety could be an interesting source of colored bioactive compounds which not only have coloring potential, but are also an excellent source of dietary antioxidant components which may have beneficial effects on consumers' health.

  10. Rearing a native cactus moth, Melitara prodenialis (Lepidoptera: Pyralidae), on artificial diet and Opuntia cladodes: Preliminary comparisons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compared several biological parameters of native cactus moth, Melitara prodenialis, reared on an artificial versus the natural diet of Opuntia spp. cladodes. Results suggest that the current artificial diet developed for mass rearing C. cactorum can provide nutritional value for the rear...

  11. External morphology of the egg of the native (Melitara prodenialis) and exotic (Cactoblastis cactorum) cactus moths (Lepidoptera: Pyralidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scanning electron microscopy was used to study the morphology of the chorionic surface of two pyralids that feed on Opuntia cactus. The chorionic surface of Cactoblastis cactorum has a reticulate pattern due to the ridges on the surface and aeropyles. The surface has a granular appearance at low m...

  12. Analysis of factors that affect the potential of star fruit (Averhoa Bilimbi) and cactus (Gymnocalycium Hossei) extracts as alternative battery

    NASA Astrophysics Data System (ADS)

    Rahmawati, Sitti; Agnesstacia

    2014-03-01

    This research analyzes the factors that affect the work of the battery from the star fruit extract and the cactus extract. The value voltage and current generated are measure the work of the battery. Voltage measurement based on the electrode distance function, and electrode surface area. Voltage as a surface area electrode function and electrode distance function determined the current density and the voltage generated. From the experimental results obtained that the battery voltage is large enough, it is about 1.8 V for the extract of star fruit, and 1.7 V for the extract of cactus, which means that the juice extract from star fruit and the juice extract of cactus can become an alternative as battery replacement. The measurements with different electrode surface area on the star fruit and cactus extract which has the depth of the electrode 0.5 cm to 4 cm causes a decrease in the electric current generated from 12.5 mA to 1.0 mA, but obtained the same voltage.

  13. Influence of radiation dose on the level of F1 sterility in the cactus moth, Cactoblastis cactorum (Lepidoptera: Pyralidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined inherited sterility effects on the F1 and F2 generations of the cactus moth, Cactoblastis cactorum (Berg), in order to identify the dose of gamma radiation that would fully sterilize F1-generation moths, which would result in no viable offspring when F1 males were inbred- or out-crossed ...

  14. Anonymous nuclear markers data supporting species tree phylogeny and divergence time estimates in a cactus species complex in South America.

    PubMed

    Perez, Manolo F; Carstens, Bryan C; Rodrigues, Gustavo L; Moraes, Evandro M

    2016-03-01

    Supportive data related to the article "Anonymous nuclear markers reveal taxonomic incongruence and long-term disjunction in a cactus species complex with continental-island distribution in South America" (Perez et al., 2016) [1]. Here, we present pyrosequencing results, primer sequences, a cpDNA phylogeny, and a species tree phylogeny. PMID:26900589

  15. Current management efforts against Cactoblastis cactorum as a pest of North American prickly pear cactus, Opuntia spp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The unintentional arrival of Cactoblastis cactorum (Lepidoptera: Pyralidae) to Florida changed the scope of this celebrated weed biological control agent from savior to pest. Based on this insects’ substantial control of non-native Opuntia spp. (prickly pear cactus) in Australia and other parts of ...

  16. Betalains, Phenols and Antioxidant Capacity in Cactus Pear [Opuntia ficus-indica (L.) Mill.] Fruits from Apulia (South Italy) Genotypes

    PubMed Central

    Albano, Clara; Negro, Carmine; Tommasi, Noemi; Gerardi, Carmela; Mita, Giovanni; Miceli, Antonio; De Bellis, Luigi; Blando, Federica

    2015-01-01

    Betacyanin (betanin), total phenolics, vitamin C and antioxidant capacity (by Trolox-equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays) were investigated in two differently colored cactus pear (Opuntia ficus-indica (L.) Mill.) genotypes, one with purple fruit and the other with orange fruit, from the Salento area, in Apulia (South Italy). In order to quantitate betanin in cactus pear fruit extracts (which is difficult by HPLC because of the presence of two isomers, betanin and isobetanin, and the lack of commercial standard with high purity), betanin was purified from Amaranthus retroflexus inflorescence, characterized by the presence of a single isomer. The purple cactus pear variety showed very high betanin content, with higher levels of phenolics, vitamin C, and antioxidant capacity (TEAC) than the orange variety. These findings confirm the potential for exploiting the autochthonous biodiversity of cactus pear fruits. In particular, the purple variety could be an interesting source of colored bioactive compounds which not only have coloring potential, but are also an excellent source of dietary antioxidant components which may have beneficial effects on consumers’ health. PMID:26783704

  17. Flavobacterium columnare: Chemotaxis and adhesion to channel catfish mucus is mediated by lectin-like capsular substances

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is an important Gram-negative pathogen of fresh water fish that may cause chronic skin lesions and severe mortality. Isolates of F. columnare belong to either the virulent genomovar II or the less virulent genomovar I. Chemotaxis and adhesion assays were conducted in vitro...

  18. Growth and survival of the fish pathogenic bacterium, Flavobacterium columnare, in tilapia mucus and porcine gastric mucin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is an economically important gram negative bacterium that infects most freshwater farmed fish worldwide. Flavobacterium columnare colonizes the skin and gills of fish in the initial steps of pathogenesis. The fish’s surface is coated with mucus made up of high molecular we...

  19. Evaluation of potassium permanganate against an experimental subacute infection of Flavobacterium columnare in channel catfish, Icatlurus punctatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficacy of potassium permanganate (KMnO4) as a prophylactic and therapeutic treatment for subacute infection of Flavobacterium columnare was demonstrated in experimentally infected channel catfish, Ictalurus punctatus. Catfish experimentally infected with F. columnare to mimic a subacute infec...

  20. Improved Pulsed-Field Gel Electrophoresis Procedure for the Analysis of F. columnare Isolates Previously Affected by DNA Degradation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is a fresh water bacterium that causes columnaris diseases in over 36 fish species. Intra-species typing of F. columnare can be performed by pulsed-field gel electrophoresis (PFGE). However, this method is hampered by the degradation of chromosomal DNA in about 10% of strain...

  1. Impact of oral and waterborne administration of rhamnolipids on the susceptibility of channel catfish (Ictalurus punctatus) to Flavobacterium columnare infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is the causative agent of columnaris disease and causes tremendous morbidity and mortality of farmed fish globally. Previously, we identified a potential lectin-mediator (a rhamnose-binding lectin; RBL1a) of F. columnare adhesion and showed higher RBL1a expression in suscept...

  2. A liquid-crystalline hexagonal columnar phase in highly-dilute suspensions of imogolite nanotubes.

    PubMed

    Paineau, Erwan; Krapf, Marie-Eve M; Amara, Mohamed-Salah; Matskova, Natalia V; Dozov, Ivan; Rouzière, Stéphan; Thill, Antoine; Launois, Pascale; Davidson, Patrick

    2016-01-01

    Liquid crystals have found wide applications in many fields ranging from detergents to information displays and they are also increasingly being used in the 'bottom-up' self-assembly approach of material nano-structuration. Moreover, liquid-crystalline organizations are frequently observed by biologists. Here we show that one of the four major lyotropic liquid-crystal phases, the columnar one, is much more stable on dilution than reported so far in literature. Indeed, aqueous suspensions of imogolite nanotubes, at low ionic strength, display the columnar liquid-crystal phase at volume fractions as low as ∼ 0.2%. Consequently, due to its low visco-elasticity, this columnar phase is easily aligned in an alternating current electric field, in contrast with usual columnar liquid-crystal phases. These findings should have important implications for the statistical physics of the suspensions of charged rods and could also be exploited in materials science to prepare ordered nanocomposites and in biophysics to better understand solutions of rod-like biopolymers.

  3. Evaluation of the antibody response to the LV-359-01 strain of flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare, the causative agent of columnaris disease produces substantial mortality worldwide among numerous freshwater farmed finfish species. As aquaculture production continues to increase the frequency of columnaris disease will only continue to rise. Add to this an increase in re...

  4. Compounds from Terminalli brownii extracts with toxicity against the fish pathogenic bacterium Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pond-raised channel catfish (Ictalurus punctatus) industry in the United States of America can incur losses of over a $100 million annually due to bacterial diseases including columnaris disease caused by Flavobacterium columnare. One management approach available to catfish producers is the use...

  5. A bundled-stack discotic columnar liquid crystalline phase with inter-stack electronic coupling

    DOE PAGESBeta

    Wang, Bin; Sun, Runkun; Günbaş, Duygu D.; Zhang, Hao; Grozema, Ferdinand C.; Xiao, Kai; Jin, Shi

    2015-06-15

    The first compound proving to be capable of forming a bundled-stack discotic columnar liquid crystalline (BSDCLC) phase was designed and synthesized. Finally, the unique perylene anhydride inter-stack interaction was found to be the key to the formation of the BSDCLC structure and inter-stack electronic coupling (ISEC).

  6. Induced stabilization of columnar phases in binary mixtures of discotic liquid crystals.

    PubMed

    Cienega-Cacerez, Octavio; García-Alcántara, Consuelo; Moreno-Razo, José Antonio; Díaz-Herrera, Enrique; Sambriski, Edward John

    2016-01-28

    Three discotic liquid-crystalline binary mixtures, characterized by their extent of bidispersity in molecular thickness, were investigated with molecular dynamics simulations. Each equimolar mixture contained A-type (thin) and B-type (thick) discogens. The temperature-dependence of the orientational order parameter reveals that A-type liquid samples produce ordered phases more readily, with the (hexagonal) columnar phase being the most structured variant. Moderately and strongly bidisperse mixtures produce globally-segregated samples for temperatures corresponding to ordered phases; the weakly bidisperse mixture displays microheterogeneities. Ordered phases in the B-type liquid are induced partially by the presence of the A-type fluid. In the moderately bidisperse mixture, order is induced through orientational frustration: a mixed prenematic-like phase precedes global segregation to yield nematic and columnar mesophases upon further cooling. In the strongly bidisperse mixture, order is induced less efficiently through a paranematic-like mechanism: a highly-ordered A-type fluid imparts order to B-type discogens found at the interface of a fully-segregated sample. This ordering effect permeates into the disordered B-type domain until nematic and columnar phases emerge upon further cooling. At sufficiently low temperatures, all samples investigated exhibit the (hexagonal) columnar mesophase.

  7. Growth and survival of Flavobacterium columnare in fish mucus and porcine gastric mucin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare, an economically important gram negative bacterium of freshwater farmed fish, colonizes the skin and gills in the initial steps of pathogenesis. The surface of fish is coated with mucus made up of high molecular weight glycoproteins. Limited studies have described the abili...

  8. Two-dimensional simulation of spatiotemporal generation of dielectric barrier columnar discharges in atmospheric helium

    SciTech Connect

    Huang, Zhiming; Hao, Yanpeng; Yang, Lin; Han, Yongxia; Li, Licheng

    2015-12-15

    A two-dimensional (2D) fluid model is presented to investigate the spatiotemporal generation and dynamic mechanics of dielectric barrier columnar discharges in atmospheric helium. The model was examined with discharge currents measured in experiments and images taken by an intensified charge couple device camera. Based on the model, a columnar discharge was simulated for several cycles after being ignited. The discharge could be regarded as an initial unstable stage for the first three and a half cycles, then a steady state for the following cycles. In the initial stage, the discharge evolves from a uniform pattern into a columnar one. The calculated equipotential lines, 2D radial electric field, and electron density distributions at the edge of uniform discharges show the radial electric field accounts for the shrinking discharge area and the formation of discharge columns in the end. The columnar glow discharges and the Townsend discharges beyond the columns could coexist in the initial stage, and a Townsend discharge might develop into a new glow column in the next half-cycle. The radial electric field surrounding a glow discharge column has an inhibiting effect on the ionization in the peripheral area.

  9. A liquid-crystalline hexagonal columnar phase in highly-dilute suspensions of imogolite nanotubes

    NASA Astrophysics Data System (ADS)

    Paineau, Erwan; Krapf, Marie-Eve M.; Amara, Mohamed-Salah; Matskova, Natalia V.; Dozov, Ivan; Rouzière, Stéphan; Thill, Antoine; Launois, Pascale; Davidson, Patrick

    2016-01-01

    Liquid crystals have found wide applications in many fields ranging from detergents to information displays and they are also increasingly being used in the `bottom-up' self-assembly approach of material nano-structuration. Moreover, liquid-crystalline organizations are frequently observed by biologists. Here we show that one of the four major lyotropic liquid-crystal phases, the columnar one, is much more stable on dilution than reported so far in literature. Indeed, aqueous suspensions of imogolite nanotubes, at low ionic strength, display the columnar liquid-crystal phase at volume fractions as low as ~0.2%. Consequently, due to its low visco-elasticity, this columnar phase is easily aligned in an alternating current electric field, in contrast with usual columnar liquid-crystal phases. These findings should have important implications for the statistical physics of the suspensions of charged rods and could also be exploited in materials science to prepare ordered nanocomposites and in biophysics to better understand solutions of rod-like biopolymers.

  10. Anisotropic light absorption, refractive indices, and orientational order parameter of unidirectionally aligned columnar liquid crystal films.

    PubMed

    Charlet, Emilie; Grelet, Eric

    2008-10-01

    The anisotropic optical properties of thermotropic columnar liquid crystals absorbing in the visible range are investigated for different discotic compounds unidirectionally oriented in open supported thin films. Two methods to monitor the alignment of columnar mesophases in thin films are reported, making possible to achieve either homeotropic anchoring (columns normal to the substrate) by a specific thermal annealing, or unidirectional planar orientation (columns parallel to the substrate) by using a rubbed Teflon coating. The columnar liquid crystal anchoring is found to depend on the nature of the compound, either parallel or perpendicular to the Teflon orientation. Based on this control of the mesophase alignment, the dichroic ratio and the orientational order parameter of oriented samples are measured, and a high order parameter of 0.9 is found in the case of parallel alignment. From the polarized absorption data of the columnar liquid crystal films, the light wavelength dependence of the birefringence and of the real and imaginary parts (refractive index and extinction coefficient, respectively) of the anisotropic optical indices are determined over the whole visible range. PMID:18999445

  11. Interplay between columnar and smectic stability in suspensions of polydisperse colloidal platelets.

    PubMed

    Velasco, Enrique; Martínez-Ratón, Yuri

    2014-01-14

    The phase behavior of a model suspension of colloidal polydisperse platelets is studied using density-functional theory. Platelets are modelled as parallel rectangular prisms of square section l(2) and height h, with length and height distributions given by different polydispersities δ(l) and δ(h). The model is intended to qualitatively represent experimental colloidal platelet suspensions at high densities with a high degree of orientational ordering. We obtain the phase behavior of the model, including nematic, smectic and columnar phases and its dependence on the two polydispersities δ(l) and δ(h). When δ(l) > δ(h) we observe that the smectic phase stabilises first with respect to the columnar. If δ(h) > δ(l) we observe the opposite behavior. Other more complicated cases occur, e.g. the smectic stabilises from the nematic first but then exists a first-order transition to the columnar phase. Our model assumes plate-rod symmetry, but the regions of stability of smectic and columnar phases are non-symmetric in the δ(l) - δ(h) plane due to the different dimensionality of ordering in the two phases. Microsegregation effects, i.e. different spatial distribution for different sizes within the periodic cell, take place in both phases and, in each case, is more apparent in the variable associated with ordering.

  12. A liquid-crystalline hexagonal columnar phase in highly-dilute suspensions of imogolite nanotubes

    PubMed Central

    Paineau, Erwan; Krapf, Marie-Eve M.; Amara, Mohamed-Salah; Matskova, Natalia V.; Dozov, Ivan; Rouzière, Stéphan; Thill, Antoine; Launois, Pascale; Davidson, Patrick

    2016-01-01

    Liquid crystals have found wide applications in many fields ranging from detergents to information displays and they are also increasingly being used in the ‘bottom-up' self-assembly approach of material nano-structuration. Moreover, liquid-crystalline organizations are frequently observed by biologists. Here we show that one of the four major lyotropic liquid-crystal phases, the columnar one, is much more stable on dilution than reported so far in literature. Indeed, aqueous suspensions of imogolite nanotubes, at low ionic strength, display the columnar liquid-crystal phase at volume fractions as low as ∼0.2%. Consequently, due to its low visco-elasticity, this columnar phase is easily aligned in an alternating current electric field, in contrast with usual columnar liquid-crystal phases. These findings should have important implications for the statistical physics of the suspensions of charged rods and could also be exploited in materials science to prepare ordered nanocomposites and in biophysics to better understand solutions of rod-like biopolymers. PMID:26728415

  13. Complex columnar hexagonal polymorphism in supramolecular assemblies of a semifluorinated electron-accepting naphthalene bisimide.

    PubMed

    Wu, Yu-Chun; Leowanawat, Pawaret; Sun, Hao-Jan; Partridge, Benjamin E; Peterca, Mihai; Graf, Robert; Spiess, Hans W; Zeng, Xiangbing; Ungar, Goran; Hsu, Chain-Shu; Heiney, Paul A; Percec, Virgil

    2015-01-21

    Simple synthetic methods for a strongly electron-accepting naphthalene bisimide (NBI) derivative functionalized with a new environmentally friendly chiral racemic semifluorinated alkyl group and with AB3 minidendrons containing the same semifluorinated group are reported. The semifluorinated dendron was attached to the imide groups of the NBI via one, two, and three (m = 1, 2, 3) methylenic units. The NBI-containing semifluorinated groups and the dendronized NBI with m = 1 and 2 self-organize into lamellar crystals. The dendronized NBI with m = 3 self-assembles into an unprecedentedly complex and ordered column that self-organizes in a columnar hexagonal periodic array. This array undergoes a continuous transition to a columnar hexagonal superlattice that does not display a first-order phase transition during analysis by differential scanning calorimetry at heating and cooling rates of 10 and 1 °C/min. These complex columnar hexagonal periodic arrays with intramolecular order could be elucidated only by a combination of powder and fiber X-ray diffraction studies and solid-state NMR experiments. The lamellar crystals self-organized from m = 1 and the two highly ordered columnar hexagonal periodic arrays of m = 3 are assembled via thermodynamically controlled processes. Since strongly electron-accepting derivatives are of great interest to replace fullerene acceptors in organic photovoltaics and for other supramolecular electronic materials, the multitechnique structural analysis methodology elaborated here must be taken into consideration in all related studies.

  14. More than just antibodies: protective mechanisms of a mucosal vaccine against fish pathogen Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recently developed attenuated vaccine (17-23) for Flavobacterium columnare has been demonstrated to provide superior protection for channel catfish, Ictalurus punctatus, against genetically diverse columnaris isolates. First, we were interested in elucidating the host responses generated by a viru...

  15. There must be something in the water (for F. columnare pathogenesis)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Why can we routinely produce columnaris infections in our lab, while the lab on the other side of the ditch can't? Anecdotal reports suggest that tannins may inhibit F. columnare. Do tannins in their water prevent this, or are other water chemistry parameters involved? In the first experiment, tw...

  16. Clinical, pathological, and immunohistochemical findings in bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) naturally infected with West Nile virus.

    PubMed

    Wünschmann, Arno; Timurkaan, Necati; Armien, Aníbal G; Bueno Padilla, Irene; Glaser, Amy; Redig, Patrick T

    2014-09-01

    Fifteen bald eagles (Haliaeetus leucocephalus) and 3 golden eagles (Aquila chrysaetos) were diagnosed with West Nile disease based on 1) presence of lesions in brain, eyes, and heart, 2) viral antigen detection in brain, eyes, heart, kidney, and/or liver by immunohistochemical staining, 3) detection of viral RNA in tissue samples and/or cerebrospinal fluid (CSF) by polymerase chain reaction, and/or 4) detection of West Nile virus (WNV)-specific antibodies in CSF by serum neutralization assay. West Nile virus-associated gross lesions included cerebral pan-necrosis with hydrocephalus ex vacuo (7/15 bald eagles), fibrin exudation into the fundus in 1 golden eagle, retinal scarring in 1 bald eagle, and myocardial pallor and rounded heart apex in 4 bald eagles. Histologic lesions included lymphoplasmacytic encephalitis, most prominently in the cerebrum (17 eagles), lymphoplasmacytic pectenitis and choroiditis (15 and 8 eagles, respectively), and myocarditis (12 eagles). West Nile virus antigen was detected in the majority of the eagles in neurons of the brain (cerebrum and cerebellum), and less commonly present in neurons of the retina, tubular epithelial cells of the kidney, and cardiomyocytes. West Nile disease was diagnosed in 2 bald eagles based on the presence of cerebral pan-necrosis and WNV-specific antibodies in the CSF despite lacking viral antigen and RNA. In conclusion, WNV infection causes a fatal disease in bald and golden eagles. A variety of gross and histologic lesions are highly suggestive of WN disease in most eagles. A combination of detection of viral antigen and/or RNA or virus-specific antibodies proved useful in confirming the diagnosis.

  17. Clinical, pathological, and immunohistochemical findings in bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) naturally infected with West Nile virus.

    PubMed

    Wünschmann, Arno; Timurkaan, Necati; Armien, Aníbal G; Bueno Padilla, Irene; Glaser, Amy; Redig, Patrick T

    2014-09-01

    Fifteen bald eagles (Haliaeetus leucocephalus) and 3 golden eagles (Aquila chrysaetos) were diagnosed with West Nile disease based on 1) presence of lesions in brain, eyes, and heart, 2) viral antigen detection in brain, eyes, heart, kidney, and/or liver by immunohistochemical staining, 3) detection of viral RNA in tissue samples and/or cerebrospinal fluid (CSF) by polymerase chain reaction, and/or 4) detection of West Nile virus (WNV)-specific antibodies in CSF by serum neutralization assay. West Nile virus-associated gross lesions included cerebral pan-necrosis with hydrocephalus ex vacuo (7/15 bald eagles), fibrin exudation into the fundus in 1 golden eagle, retinal scarring in 1 bald eagle, and myocardial pallor and rounded heart apex in 4 bald eagles. Histologic lesions included lymphoplasmacytic encephalitis, most prominently in the cerebrum (17 eagles), lymphoplasmacytic pectenitis and choroiditis (15 and 8 eagles, respectively), and myocarditis (12 eagles). West Nile virus antigen was detected in the majority of the eagles in neurons of the brain (cerebrum and cerebellum), and less commonly present in neurons of the retina, tubular epithelial cells of the kidney, and cardiomyocytes. West Nile disease was diagnosed in 2 bald eagles based on the presence of cerebral pan-necrosis and WNV-specific antibodies in the CSF despite lacking viral antigen and RNA. In conclusion, WNV infection causes a fatal disease in bald and golden eagles. A variety of gross and histologic lesions are highly suggestive of WN disease in most eagles. A combination of detection of viral antigen and/or RNA or virus-specific antibodies proved useful in confirming the diagnosis. PMID:25085868

  18. Gene deletion strategy to examine the involvement of the two chondroitin lyases in Flavobacterium columnare virulence.

    PubMed

    Li, Nan; Qin, Ting; Zhang, Xiao Lin; Huang, Bei; Liu, Zhi Xin; Xie, Hai Xia; Zhang, Jin; McBride, Mark J; Nie, Pin

    2015-11-01

    Flavobacterium columnare is an important bacterial pathogen of freshwater fish that causes high mortality of infected fish and heavy economic losses in aquaculture. The pathogenesis of this bacterium is poorly understood, in part due to the lack of efficient methods for genetic manipulation. In this study, a gene deletion strategy was developed and used to determine the relationship between the production of chondroitin lyases and virulence. The F. johnsoniae ompA promoter (PompA) was fused to sacB to construct a counterselectable marker for F. columnare. F. columnare carrying PompA-sacB failed to grow on media containing 10% sucrose. A suicide vector carrying PompA-sacB was constructed, and a gene deletion strategy was developed. Using this approach, the chondroitin lyase-encoding genes, cslA and cslB, were deleted. The ΔcslA and ΔcslB mutants were both partially deficient in digestion of chondroitin sulfate A, whereas a double mutant (ΔcslA ΔcslB) was completely deficient in chondroitin lyase activity. Cells of F. columnare wild-type strain G4 and of the chondroitin lyase-deficient ΔcslA ΔcslB mutant exhibited similar levels of virulence toward grass carp in single-strain infections. Coinfections, however, revealed a competitive advantage for the wild type over the chondroitin lyase mutant. The results indicate that chondroitin lyases are not essential virulence factors of F. columnare but may contribute to the ability of the pathogen to compete and cause disease in natural infections. The gene deletion method developed in this study may be employed to investigate the virulence factors of this bacterium and may have wide application in many other members of the phylum Bacteroidetes.

  19. Efficacy of florfenicol for control of mortality caused by Flavobacterium columnare infection in channel catfish.

    PubMed

    Gaunt, Patricia S; Gao, Dana; Sun, Fangshi; Endris, Richard

    2010-06-01

    The studied in channel catfish Ictalurus punctatus fingerlings held in 80-L aquaria. Nonabraded fish were challenged by immersion on day 0. Thirty 80-L tanks were randomly assigned in equal numbers to two treatment groups, one in which fish were fed a commercial diet without florfenicol (unmedicated feed) and one in which they were fed a diet containing 10 mg of florfenicol/kg of body weight (medicated feed) for ten consecutive days. Mortality was monitored during the treatment period and a 14-d posttreatment observation period. At the end of the posttreatment period, all fish were euthanized, examined for gross lesions, and cultured for F. columnare. Significantly fewer fish fed the medicated diet died (8.0%) than fish fed the unmedicated diet (54.2%). Flavobacterium columnare was cultured from 15.0% of the medicated fish, compared with 68.9% of the unmedicated fish. The gross lesions in the fish were consistent with columnaris disease, and F. columnare was cultured from 99.5% of the dead fish. No differences were observed in weight gain and appetence between the medicated and unmedicated groups. For the F. columnare strain used in this study, the minimal inhibitory concentration of florfenicol ranged from 0.5 to 1.0 mg/mL in the 30 bacterial cultures obtained from infected fish, and the mean disk diffusion zone of inhibition was 40 mm. There were no adverse effects among the medicated fish. Administration of florfenicol at a dosage of 10 mg/kg body weight for 10 d was efficacious and safe for the control of mortality from F. columnare infection in channel catfish.

  20. Gene deletion strategy to examine the involvement of the two chondroitin lyases in Flavobacterium columnare virulence.

    PubMed

    Li, Nan; Qin, Ting; Zhang, Xiao Lin; Huang, Bei; Liu, Zhi Xin; Xie, Hai Xia; Zhang, Jin; McBride, Mark J; Nie, Pin

    2015-11-01

    Flavobacterium columnare is an important bacterial pathogen of freshwater fish that causes high mortality of infected fish and heavy economic losses in aquaculture. The pathogenesis of this bacterium is poorly understood, in part due to the lack of efficient methods for genetic manipulation. In this study, a gene deletion strategy was developed and used to determine the relationship between the production of chondroitin lyases and virulence. The F. johnsoniae ompA promoter (PompA) was fused to sacB to construct a counterselectable marker for F. columnare. F. columnare carrying PompA-sacB failed to grow on media containing 10% sucrose. A suicide vector carrying PompA-sacB was constructed, and a gene deletion strategy was developed. Using this approach, the chondroitin lyase-encoding genes, cslA and cslB, were deleted. The ΔcslA and ΔcslB mutants were both partially deficient in digestion of chondroitin sulfate A, whereas a double mutant (ΔcslA ΔcslB) was completely deficient in chondroitin lyase activity. Cells of F. columnare wild-type strain G4 and of the chondroitin lyase-deficient ΔcslA ΔcslB mutant exhibited similar levels of virulence toward grass carp in single-strain infections. Coinfections, however, revealed a competitive advantage for the wild type over the chondroitin lyase mutant. The results indicate that chondroitin lyases are not essential virulence factors of F. columnare but may contribute to the ability of the pathogen to compete and cause disease in natural infections. The gene deletion method developed in this study may be employed to investigate the virulence factors of this bacterium and may have wide application in many other members of the phylum Bacteroidetes. PMID:26253667

  1. Analysis of EDZ Development of Columnar Jointed Rock Mass in the Baihetan Diversion Tunnel

    NASA Astrophysics Data System (ADS)

    Hao, Xian-Jie; Feng, Xia-Ting; Yang, Cheng-Xiang; Jiang, Quan; Li, Shao-Jun

    2016-04-01

    Due to the time dependency of the crack propagation, columnar jointed rock masses exhibit marked time-dependent behaviour. In this study, in situ measurements, scanning electron microscope (SEM), back-analysis method and numerical simulations are presented to study the time-dependent development of the excavation damaged zone (EDZ) around underground diversion tunnels in a columnar jointed rock mass. Through in situ measurements of crack propagation and EDZ development, their extent is seen to have increased over time, despite the fact that the advancing face has passed. Similar to creep behaviour, the time-dependent EDZ development curve also consists of three stages: a deceleration stage, a stabilization stage, and an acceleration stage. A corresponding constitutive model of columnar jointed rock mass considering time-dependent behaviour is proposed. The time-dependent degradation coefficient of the roughness coefficient and residual friction angle in the Barton-Bandis strength criterion are taken into account. An intelligent back-analysis method is adopted to obtain the unknown time-dependent degradation coefficients for the proposed constitutive model. The numerical modelling results are in good agreement with the measured EDZ. Not only that, the failure pattern simulated by this time-dependent constitutive model is consistent with that observed in the scanning electron microscope (SEM) and in situ observation, indicating that this model could accurately simulate the failure pattern and time-dependent EDZ development of columnar joints. Moreover, the effects of the support system provided and the in situ stress on the time-dependent coefficients are studied. Finally, the long-term stability analysis of diversion tunnels excavated in columnar jointed rock masses is performed.

  2. The cactus effect: an alternative to the lupin effect for increasing ovulation rate in sheep reared in semi-arid regions?

    PubMed

    Rekik, M; Gonzalez-Bulnes, A; Lassoued, N; Ben Salem, H; Tounsi, A; Ben Salem, I

    2012-04-01

    The present study evaluated the effects of supplementation with cactus cladodes on follicular dynamics and ovulatory response of sheep reared in semi-arid areas. A total of 76 ewes were distributed into two equal groups supplemented with either concentrated feed or cactus cladodes. After 30 days of supplementation, no differences were found between feeding regimens on the final live weight (LW; 41.5 ± 0.6 and 42.1 ± 0.7 kg in the Concentrate and Cactus groups respectively) and body condition score (BCS; 1.8 ± 0.3 and 1.8 ± 0.4 for Concentrate and Cactus group respectively). Moreover, no differences were found between the initial and the final values of both LW and BCS; thus, there were no effects of supplementation on any of both parameters. Analysis of follicular population showed that, during the follicular phase induced by ram effect, the number of follicles reaching ovulatory size increased in both groups. However, the number was always higher in Cactus ewes and, at oestrus, Cactus ewes had 1.6 ± 0.2 and Concentrate sheep had 1.2 ± 0.2 large follicles (p < 0.05). Thereafter, ovulation rate was affected by duration of supplementation; being higher in sheep fed with cactus for 6-10 days (1.7 ± 0.1) than in ewes supplied with cactus for more than 11 days (1.3 ± 0.1; p < 0.05), in sheep fed with concentrate for 6-10 days (1.2 ± 0.1; p < 0.01) and even than in individuals subjected to classical flushing with concentrate (1.3 ± 0.1; p < 0.05).

  3. Evaluation of the hormonal state of columnar apple trees (Malus x domestica) based on high throughput gene expression studies.

    PubMed

    Krost, Clemens; Petersen, Romina; Lokan, Stefanie; Brauksiepe, Bastienne; Braun, Peter; Schmidt, Erwin R

    2013-02-01

    The columnar phenotype of apple trees (Malus x domestica) is characterized by a compact growth habit with fruit spurs instead of lateral branches. These properties provide significant economic advantages by enabling high density plantings. The columnar growth results from the presence of a dominant allele of the gene Columnar (Co) located on chromosome 10 which can appear in a heterozygous (Co/co) or homozygous (Co/Co) state. Although two deep sequencing approaches could shed some light on the transcriptome of columnar shoot apical meristems (SAMs), the molecular mechanisms of columnar growth are not yet elaborated. Since the influence of phytohormones is believed to have a pivotal role in the establishment of the phenotype, we performed RNA-Seq experiments to study genes associated with hormone homeostasis and clearly affected by the presence of Co. Our results provide a molecular explanation for earlier findings on the hormonal state of columnar apple trees. Additionally, they allow hypotheses on how the columnar phenotype might develop. Furthermore, we show a statistically approved enrichment of differentially regulated genes on chromosome 10 in the course of validating RNA-Seq results using additional gene expression studies.

  4. Ultrastructure of turnip crinkle- and saguaro cactus virus-infected tissues.

    PubMed

    Russo, M; Martelli, G P

    1982-04-15

    An electron microscope study of different hosts infected with turnip crinkle (TCV) and saguaro cactus (SCV) viruses, two tentative members of the tombusvirus group, was carried out. Particles of both viruses were readily detected in cells of different tissues, in the cytoplasm of which they occurred in great numbers, though not in crystalline arrays. Cytological modifications of various types were also observed. The most striking of these was an extensive peripheral vesiculation of mitochondria in TCV-infected cells, which was accompanied by plastic activity of the organelles that often engulfed portions of ground cytoplasm and virus particles. Cytoplasmic inclusion bodies were not present. Likewise, none of the cytopathological features characterizing tombusvirus infections was observed. No indications were obtained to support the idea that TCV and SCV may continue to be considered members, even though tentative, of the tombusvirus group. PMID:18635129

  5. Cactus alkaloids. XLVII. N alpha-dimethylhistamine, a hypotensive component of Echinocereus triglochidiatus.

    PubMed

    Ferrigni, N R; Nichols, D E; McLaughlin, J L; Bye, R A

    1982-05-01

    Echinocereus triglochidiatus Engelm. var. neomexicanus (Standley) Standley ex W. T. Marshall is believed to cause psychotropic effects when consumed by the Mexican Tarahumara Indians. A phytochemical study was initiated with E. triglochidiatus Engelm. var. paucispinus Engelm. ex W. T. Marshall, which is more abundant in Texas. In the fractionated extracts three compounds, detected by thin-layer chromatography, were positive to Ehrlich's reagent, indicating the possible presence of indole alkaloids; however, a non-Erhlich positive alkaloid was crystallized as the dihydrochloride and subsequently identified (spectrometrically and via synthesis as N alpha, N alpha-dimethylhistamine dihydrochloride. The same compound was then detected chromatographically in the neomexicanus variety. This compound has peripheral hypotensive effects similar to histamine, and this action may help to explain the alleged psychotrophic effects of the cactus.

  6. Chemical composition and antibacterial activity of Opuntia ficus-indica f. inermis (cactus pear) flowers.

    PubMed

    Ennouri, Monia; Ammar, Imene; Khemakhem, Bassem; Attia, Hamadi

    2014-08-01

    Opuntia ficus-indica f. inermis (cactus pear) flowers have wide application in folk medicine. However, there are few reports focusing on their biological activity and were no reports on their chemical composition. The nutrient composition and hexane extracts of Opuntia flowers at 4 flowering stages and their antibacterial and antifungal activities were investigated. The chemical composition showed considerable amounts of fiber, protein, and minerals. Potassium (K) was the predominant mineral followed by calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), and zinc (Zn). The main compounds in the various hexane extracts were 9.12-octadecadienoic acid (29-44%) and hexadecanoic acid (8.6-32%). The antibacterial activity tests showed that O. inermis hexane extracts have high effectiveness against Escherichia coli and Staphylococcus aureus, making this botanical source a potential contender as a food preservative or food control additive.

  7. A cactus-derived toxin-like cystine knot Peptide with selective antimicrobial activity.

    PubMed

    Aboye, Teshome L; Strömstedt, Adam A; Gunasekera, Sunithi; Bruhn, Jan G; El-Seedi, Hesham; Rosengren, K Johan; Göransson, Ulf

    2015-05-01

    Naturally occurring cystine knot peptides show a wide range of biological activity, and as they have inherent stability they represent potential scaffolds for peptide-based drug design and biomolecular engineering. Here we report the discovery, sequencing, chemical synthesis, three-dimensional solution structure determination and bioactivity of the first cystine knot peptide from Cactaceae (cactus) family: Ep-AMP1 from Echinopsis pachanoi. The structure of Ep-AMP1 (35 amino acids) conforms to that of the inhibitor cystine knot (or knottin) family but represents a novel diverse sequence; its activity was more than 500 times higher against bacterial than against eukaryotic cells. Rapid bactericidal action and liposome leakage implicate membrane permeabilisation as the mechanism of action. Sequence homology places Ec-AMP1 in the plant C6-type of antimicrobial peptides, but the three dimensional structure is highly similar to that of a spider neurotoxin.

  8. The effects of cactus inspired spines on the aerodynamics of a cylinder

    NASA Astrophysics Data System (ADS)

    Levy, Benjamin; Liu, Yingzheng

    2013-05-01

    The effect of cactus-like spines on the topology and the dynamics of the flow past a stationary or pivoted cylinder are experimentally studied. The experiments are performed either in a water channel or a wind tunnel at low to moderate Reynolds number (390-12 500). The instantaneous velocity field is recorded using TR-PIV and investigated for three different configurations: no spines, short spines (0.1D) and long spines (0.2D). The results show how the spines are able to slow the flow past the cylinder and then increase the recirculation area by up to 128% while the maximum fluctuating kinetic energy intensity is decreased by up to 35%. Moreover, the spines have a significant effect on the vortex shedding and the dynamic pressure at the surface of the cylinder, thus significantly reducing both the amplitude and the frequency at which a pivoted cylinder oscillates.

  9. Corrective action plan for CAU 426: Cactus Spring Waste Trenches, Tonopah Test Range

    SciTech Connect

    1997-09-01

    This Corrective Action Plan (CAP) provides the selected corrective action alternative and proposes the closure implementation methodology for the Cactus Spring Waste Trenches Corrective Action Unit (CAU) No. 426. The site is located on the Tonopah Test Range (TTR), approximately 225 kilometers (km) (140 miles) northwest of Las Vegas, Nevada. The US Department of Energy/Nevada Operations Office (DOE/NV) verbally requested approval for the schedule to be accelerated from the Nevada Division of Environmental Protection (NDEP) in July 1997. Currently, field closure activities are anticipated to be completed by September 30, 1997. CAU 426 consists of one Corrective Action Site (CAS) comprised of four waste trenches. The trenches were excavated to receive solid waste generated in support of Operation Roller Coaster, primarily the Double Tracks Test in 1963.

  10. Genetic variability of Dactylopius opuntiae (Hemiptera, Dactylopiidae) on forage cactus in northeast Brazil.

    PubMed

    Silva, D M P; do E S Mergulhão, A C; de Medeiros, L V; Figueiredo, M V B; Burity, H A

    2013-10-30

    The carmine cochineal Dactylopius opuntiae is a key pest in productive fields of forage cactus in Pernambuco, Brazil. Species identification by means of molecular markers assists in understanding the genetic profile, underpins morphological characterization, and supports the monitoring of populations in integrated management programs designed to control this pest. We evaluated the genetic variability of natural populations of D. opuntiae. Genetic variability was analyzed with ISSR and RAPD primers in 24 populations from 12 municipalities of Pernambuco State in Brazil. Morphological characterization confirmed that D. opuntiae was the only cochineal species present in all samples. Nine ISSR primers and six RAPD produced a total of 62 and 58 polymorphic fragments, respectively. Both types of markers showed an average genetic similarity of 80% regardless of the geographic origin of samples. The low genetic variability demonstrates a high degree of relatedness among these D. opuntiae populations.

  11. Genetic variability of Dactylopius opuntiae (Hemiptera, Dactylopiidae) on forage cactus in northeast Brazil.

    PubMed

    Silva, D M P; do E S Mergulhão, A C; de Medeiros, L V; Figueiredo, M V B; Burity, H A

    2013-01-01

    The carmine cochineal Dactylopius opuntiae is a key pest in productive fields of forage cactus in Pernambuco, Brazil. Species identification by means of molecular markers assists in understanding the genetic profile, underpins morphological characterization, and supports the monitoring of populations in integrated management programs designed to control this pest. We evaluated the genetic variability of natural populations of D. opuntiae. Genetic variability was analyzed with ISSR and RAPD primers in 24 populations from 12 municipalities of Pernambuco State in Brazil. Morphological characterization confirmed that D. opuntiae was the only cochineal species present in all samples. Nine ISSR primers and six RAPD produced a total of 62 and 58 polymorphic fragments, respectively. Both types of markers showed an average genetic similarity of 80% regardless of the geographic origin of samples. The low genetic variability demonstrates a high degree of relatedness among these D. opuntiae populations. PMID:24301784

  12. Cactus and Visapult: A case study of ultra-high performance distributed visualization using connectionless protocols

    SciTech Connect

    Shalf, John; Bethel, E. Wes

    2002-05-07

    This past decade has seen rapid growth in the size, resolution, and complexity of Grand Challenge simulation codes. Many such problems still require interactive visualization tools to make sense of multi-terabyte data stores. Visapult is a parallel volume rendering tool that employs distributed components, latency tolerant algorithms, and high performance network I/O for effective remote visualization of massive datasets. In this paper we discuss using connectionless protocols to accelerate Visapult network I/O and interfacing Visapult to the Cactus General Relativity code to enable scalable remote monitoring and steering capabilities. With these modifications, network utilization has moved from 25 percent of line-rate using tuned multi-streamed TCP to sustaining 88 percent of line rate using the new UDP-based transport protocol.

  13. Viruses in laboratory-reared cactus moth, Cactoblastis cactorum (Lepidoptera: Pyralidae)

    SciTech Connect

    Marti, O.G.; Myers, R.E.; Carpenter, J.E.; Styer, E.L.

    2007-03-15

    The cactus moth, Cactoblastis cactorum (Lepidoptera: Pyralidae: Phycitinae), is a non-native species threatening a variety of native cacti, particularly endangered species of Opuntia (Zimmerman et al. 2001), on the coast of the Gulf of Mexico. Cactoblastis cactorum populations have expanded from Florida northward along the Atlantic coast as far as Charleston, SC, and westward along the Gulf of Mexico to Dauphin Island, south of Mobile, AL. It is feared that further movement to the west will allow C. cactorum to enter the US desert Southwest and Mexico, particularly the latter. Numerous cactus species, especially those of the genera Opuntia and Nopalea, are native to the U.S. and Mexico. Local economies based on agricultural and horticultural uses of cacti could be devastated by C. cactorum (Vigueras and Portillo 2001). A bi-national control program between the US and Mexico is being developed, utilizing the sterile insect technique (SIT). In the SIT program, newly emerged moths are irradiated with a {sup 60}Co source and released to mate with wild individuals. The radiation dose completely sterilizes the females and partially sterilizes the males. When irradiated males mate with wild females, the F1 progeny of these matings are sterile. In order for the SIT program to succeed, large numbers of moths must be reared from egg to adult on artificial diet in a quarantined rearing facility (Carpenter et al. 2001). Irradiated insects must then be released in large numbers at the leading edge of the invasive population and at times which coincide with the presence of wild individuals available for mating. Mortality from disease in the rearing colony disrupts the SIT program by reducing the numbers of insects available for release.

  14. Genesis of the columnar joints from welded tuff in Mount Mudeung National Geopark, Republic of Korea

    NASA Astrophysics Data System (ADS)

    Lim, Chungwan; Huh, Min; Yi, Keewook; Lee, Changyeol

    2015-09-01

    Mount Mudeung National Geopark (MMNG), Gwangju, Republic of Korea (1187 masl), is known for its huge, broad occurrences of columnar jointed colonnades in the Cretaceous Mudeungsan Tuff. To understand the genesis of columnar joints infilling a volcanic vent, integrated geochemical and geophysical studies were conducted. Most colonnades in the Geopark are located in regions higher than 700 masl and show elevation-dependent variations in the mean face width of the columns. These mean widths are approximately 1.7, 1.3, 2.9, and 1.2 m for the summit (>1100 masl), upper (950-1100 masl), lower (850-950 masl), and lowest (700-850 masl) colonnades, respectively. This variation implies that columnar jointing resulted from discontinuous tuff depositions on relatively planar ground, which is associated with caldera structures and landslides from the emptied caldera rim. Geochemical analyses of major, minor, and trace elements show that the andesitic-dacitic Mudeungsan Tuff resulted from the arc magmatism associated with subduction of the Izanagi Plate and involved crustal components. Few geochemical variations of the Mudeungsan Tuff indicate that tuff originated from a single magma chamber. U-Pb age dating indicates that the Mudeungsan Tuff was deposited at ~85 Ma except for the Chotdae-bong colonnades, which were dated to ~87 Ma. However, a scaling analysis of the elevation-dependent variations of face widths and simplified numerical model calculations indicate that the variation in face widths with elevation indicates the sequential emplacement, cooling, and compaction of separate welded tuffs. Thus, the welded tuffs of MMNG can be thought to be formed by three discontinuous large explosive eruptions with periods of repose after each eruption. These tuffs include 1) the highest-elevation columnar joints of colonnades in the summit area (>1100 m), corresponding to the lower colonnades of the third tuff; 2) the intermediate-elevation columnar joints of colonnades

  15. Characterization and Comparison of Serratia Marcescens Isolated from Edible Cactus and from Silkworm for Virulence Potential and Chitosan Susceptibility

    PubMed Central

    Li, Bin; Yu, Rongrong; Liu, Baoping; Tang, Qiaomei; Zhang, Guoqing; Wang, Yanli; Xie, Guanlin; Sun, Guochang

    2011-01-01

    Representative strains of Serratia marcescens from an edible cactus plant and silkworms were characterized and a comparison based on their cellular fatty acid composition, 16S rRNA and groE gene sequence analysis as well as silkworm virulence and chitosan susceptibility was carried out. Results from this study indicate that there are no significant differences between the phenotypic and molecular characterization, virulence and chitosan susceptibility of the S. marcescens strains from the cactus plant and silkworms. Silkworms inoculated with S. marcescens from either plant or silkworm resulted in nearly 100% mortality. Chitosan solution exhibited strong antibacterial activity against S. marcescens. This activity increased with the increase of chitosan concentration and incubation time regardless of the strain source. Also, the results indicate that the plant associated S. marcescens maybe plays a possible role in the contamination of humans and animals, in particular silkworms, while chitosan showed a potential to control the contamination caused by S. marcescens. PMID:24031610

  16. Characterization and comparison of serratia marcescens isolated from edible cactus and from silkworm for virulence potential and chitosan susceptibility.

    PubMed

    Li, Bin; Yu, Rongrong; Liu, Baoping; Tang, Qiaomei; Zhang, Guoqing; Wang, Yanli; Xie, Guanlin; Sun, Guochang

    2011-01-01

    Representative strains of Serratia marcescens from an edible cactus plant and silkworms were characterized and a comparison based on their cellular fatty acid composition, 16S rRNA and groE gene sequence analysis as well as silkworm virulence and chitosan susceptibility was carried out. Results from this study indicate that there are no significant differences between the phenotypic and molecular characterization, virulence and chitosan susceptibility of the S. marcescens strains from the cactus plant and silkworms. Silkworms inoculated with S. marcescens from either plant or silkworm resulted in nearly 100% mortality. Chitosan solution exhibited strong antibacterial activity against S. marcescens. This activity increased with the increase of chitosan concentration and incubation time regardless of the strain source. Also, the results indicate that the plant associated S. marcescens maybe plays a possible role in the contamination of humans and animals, in particular silkworms, while chitosan showed a potential to control the contamination caused by S. marcescens.

  17. Topological Control of Columnar Stacking Made of Liquid-Crystalline Thiophene-Fused Metallonaphthalocyanines.

    PubMed

    Suzuki, Hiroyuki; Kawano, Koki; Ohta, Kazuchika; Shimizu, Yo; Kobayashi, Nagao; Kimura, Mutsumi

    2016-04-01

    The spontaneous organization of two-dimensional polyaromatic molecules into well-defined nanostructures through noncovalent interactions is important in the development of organic-based electronic and optoelectronic devices. Two regioisomers of thiophene-fused zinc naphthalocyanines ZnTNcendo and ZnTNcexo have been designed and synthesized to obtain photo- and electroactive liquid crystalline materials. Both compounds exhibited liquid crystalline behavior over a wide temperature range through intermolecular π-π interactions and local phase segregation between the aromatic cores and peripheral side chains. The structural differences between ZnTNcendo and ZnTNcexo affected the stacking mode in self-assembled columns, as well as symmetry of the two-dimensional rectangular columnar lattice. The columnar structure in liquid crystalline phase exhibited an ambipolar charge-transport behavior. PMID:27308226

  18. Discotic columnar liquid crystal studied in the bulk and nanoconfined states by molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Busselez, Rémi; Cerclier, Carole V.; Ndao, Makha; Ghoufi, Aziz; Lefort, Ronan; Morineau, Denis

    2014-10-01

    A prototypical Gay Berne discotic liquid crystal was studied by means of molecular dynamics simulations both in the bulk state and under confinement in a nanoporous channel. The phase behavior of the confined system strongly differs from its bulk counterpart: the bulk isotropic-to-columnar transition is replaced by a continuous ordering from a paranematic to a columnar phase. Moreover, a new transition is observed at a lower temperature in the confined state, which corresponds to a reorganization of the intercolumnar order. It reflects the competing effects of pore surface interaction and genuine hexagonal packing of the columns. The translational molecular dynamics in the different phases has been thoroughly studied and discussed in terms of collective relaxation modes, non-Gaussian behavior, and hopping processes.

  19. Columnar order and Ashkin-Teller criticality in mixtures of hard squares and dimers.

    PubMed

    Ramola, Kabir; Damle, Kedar; Dhar, Deepak

    2015-05-15

    We show that critical exponents of the transition to columnar order in a mixture of 2×1 dimers and 2×2 hard squares on the square lattice depends on the composition of the mixture in exactly the manner predicted by the theory of Ashkin-Teller criticality, including in the hard-square limit. This result settles the question regarding the nature of the transition in the hard-square lattice gas. It also provides the first example of a polydisperse system whose critical properties depend on composition. Our ideas also lead to some interesting predictions for a class of frustrated quantum magnets that exhibit columnar ordering of the bond energies at low temperature. PMID:26024157

  20. Self-assembly of luminescent N-annulated perylene tetraesters into fluid columnar phases.

    PubMed

    Gupta, Ravindra Kumar; Pathak, Suraj Kumar; Pradhan, Balaram; Shankar Rao, D S; Krishna Prasad, S; Achalkumar, Ammathnadu S

    2015-05-14

    A new class of N-annulated perylene tetraesters and their N-alkylated derivatives has been synthesized. N-Annulated perylene tetraesters stabilize a hexagonal columnar phase over a broad temperature range. The hexagonal columnar phase exhibited by these compounds shows good homeotropic alignment with few defects. Annulation in the bay region of the perylene tetraesters enhanced the width of the mesophase compared with the parent tetraesters. N-Alkylation of these compounds perturbed the self-assembly behaviour and the resulting compounds were non-mesomorphic. A bright green luminescence was visible under long wavelength UV light. These properties suggest that these materials may have promising applications in organic electronics. PMID:25812168

  1. The effect of vapor incidence angle upon thin film columnar growth

    SciTech Connect

    Mazor, A.; Bukiet, B.G.; Srolovitz, D.J.

    1988-01-01

    We present a generalized theory for the growth of columnar microstructure in vapor deposited thin films under the joint influence of a constant uniform deposition flux coming down with arbitrarily chosen incidence angle, and surface diffusion. The dependences of the Zone I to Zone II transition temperature, and the characteristic length scales associated with the unstable modes on the deposition angle are predicted. The surface morphology is obtained as a function of vapor incidence angle. For a specific deposition angle, there is a one-parameter family of steady-state surface profiles which corresponds to a range of possible columnar orientation angles, among which only one angle is associated with the tangent rule. These results agree with experimental observations. 10 refs., 6 figs.

  2. Topological Control of Columnar Stacking Made of Liquid‐Crystalline Thiophene‐Fused Metallonaphthalocyanines

    PubMed Central

    Suzuki, Hiroyuki; Kawano, Koki; Ohta, Kazuchika; Shimizu, Yo; Kobayashi, Nagao

    2015-01-01

    Abstract The spontaneous organization of two‐dimensional polyaromatic molecules into well‐defined nanostructures through noncovalent interactions is important in the development of organic‐based electronic and optoelectronic devices. Two regioisomers of thiophene‐fused zinc naphthalocyanines ZnTNcendo and ZnTNcexo have been designed and synthesized to obtain photo‐ and electroactive liquid crystalline materials. Both compounds exhibited liquid crystalline behavior over a wide temperature range through intermolecular π–π interactions and local phase segregation between the aromatic cores and peripheral side chains. The structural differences between ZnTNcendo and ZnTNcexo affected the stacking mode in self‐assembled columns, as well as symmetry of the two‐dimensional rectangular columnar lattice. The columnar structure in liquid crystalline phase exhibited an ambipolar charge‐transport behavior. PMID:27308226

  3. Modelling the viscoplastic behavior and the heterogeneous intracrystalline deformation of columnar ice polycrystals

    SciTech Connect

    Lebensohn, Ricardo A; Montagnat, Maurine; Mansuy, Philippe; Duval, Paul; Philip, A

    2008-01-01

    A full-field formulation based on Fast Fourier Transforms (FFT) has been adapted and used to predict the micromechanical fields that develop in columnar Ih ice polycrystals deforming in compression by dislocation creep. The predicted intragranular mechanical fields are in qualitative good agreement with experimental observations, in particular those involving the formation of shear and kink bands. These localization bands are associated with the large internal stresses that develop during creep in such anisotropic material, and their location, intensity, morphology and extension are found to depend strongly on the crystallographic orientation of the grains and on their interaction with neighbor crystals. The predictions of the model are also discussed in relation with the deformation of columnar sea and lake ice, and with the mechanical behavior of granular ice of glaciers and polar ice sheets, as well.

  4. Corrrective action decision document for the Cactus Spring Waste Trenches (Corrective Action Unit No. 426). Revision No. 1

    SciTech Connect

    1997-06-01

    The Corrective Action Decision Document (CADD) for the Cactus Spring Waste Trenches (Corrective Action Unit [CAU] No. 426) has been prepared for the US Department of Energy`s (DOE) Nevada Environmental Restoration Project. This CADD has been developed to meet the requirements of the Federal Facility Agreement and Consent Order (FFACO) of 1996, stated in Appendix VI, {open_quotes}Corrective Action Strategy{close_quotes} (FFACO, 1996). The Cactus Spring Waste Trenches Corrective Action Site (CAS) No. RG-08-001-RG-CS is included in CAU No. 426 (also referred to as the {open_quotes}trenches{close_quotes}); it has been identified as one of three potential locations for buried, radioactively contaminated materials from the Double Tracks Test. The trenches are located on the east flank of the Cactus Range in the eastern portion of the Cactus Spring Ranch at the Tonopah Test Range (TTR) in Nye County, Nevada, on the northern portion of Nellis Air Force Range. The TTR is approximately 225 kilometers (km) (140 miles [mi]) northwest of Las Vegas, Nevada, by air and approximately 56 km (35 mi) southeast of Tonopah, Nevada, by road. The trenches were dug for the purpose of receiving waste generated during Operation Roller Coaster, primarily the Double Tracks Test. This test, conducted in 1963, involved the use of live animals to assess the biological hazards associated with non-nuclear detonation of plutonium-bearing devices (i.e., inhalation uptake of plutonium aerosol). The CAS consists of four trenches that received solid waste and had an overall impacted area of approximately 36 meters (m) (120 feet [ft]) long x 24 m (80 ft) wide x 3 to 4.5 m (10 to 15 ft) deep. The average depressions at the trenches are approximately 0.3 m (1 ft) below land surface.

  5. Cactus (Opuntia ficus-indica) cladodes prevent oxidative damage induced by the mycotoxin zearalenone in Balb/C mice.

    PubMed

    Zourgui, Lazhar; Golli, Emna El; Bouaziz, Chayma; Bacha, Hassen; Hassen, Wafa

    2008-05-01

    Zearalenone (ZEN) is one of the most widely distributed fusarial mycotoxins which is encountered at high incidence in many foodstuffs. ZEN was associated with different reproductive disorders in animals. Several in vivo studies have shown that ZEN is hepatotoxic, haematotoxic and causes several alterations of immunological parameters. Furthermore, evidence of its cytotoxicity and genotoxicity has recently emerged from several reports. The aim of the current study was (i) to find out whether oxidative stress could be relevant for ZEN induced toxicity in vivo using Balb/c mice and (ii) to evaluate the safety and efficacy of cactus cladodes Opuntia ficus to prevent the deleterious effects of ZEN. To this end, the effect of a single dose of ZEN (40 mg/kg b.w.) alone and with extract of cactus cladodes (25, 50 and 100 mg/kg b.w.) on the induction of oxidative stress was monitored in kidney and liver by measuring the MDA level, the protein carbonyls generation, the catalase activity and the expression of the heat shock proteins (Hsp). Our results clearly showed that ZEN induced significant alterations in all tested oxidative stress markers. Oxidative damage seems to be a key determinant of ZEN induced toxicity in both liver and kidney of Balb/c mice. The combined treatment of ZEN with the lowest tested dose of cactus extracts (25 mg/kg b.w.) showed a total reduction of ZEN induced oxidative damage for all tested markers. It could be concluded that cactus cladodes extract was effective in the protection against ZEN hazards. This could be relevant, particularly with the emergent demand for natural products which may counteract the detrimental effects of oxidative stress and therefore prevent multiple human diseases. PMID:18313193

  6. Survival of vaccinated, feed-trained largemouth bass fry (Micropterus salmoides floridanus) during natural exposure to Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccinated, feed-trained largemouth bass fry (Micropterus salmoides floridanus) were cohabited with sham-vaccinated fish. Fish were exposed, under natural conditions, to Flavobacterium columnare, a ubiquitous bacterium associated with columnaris disease. During every time interval, the probability...

  7. Quality control ranges for testing broth microdilution susceptibility of Flavobacterium columnare and F. psychrophilium to nine antimicrobials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multi-laboratory broth microdilution method trial was performed to standardize the specialized test conditions required for fish pathogens Flavobacterium columnare and F. pyschrophilum. Nine laboratories tested the quality control (QC) strains Escherichia coli ATCC 25922 and Aeromonas salmonicid...

  8. A cyclopalladated complex of corannulene with a pyridine pendant and its columnar self-assembly.

    PubMed

    Yamada, Mihoko; Tashiro, Shohei; Miyake, Ryosuke; Shionoya, Mitsuhiko

    2013-03-14

    Bowl-shaped corannulene provides various metal binding modes with its curved π-surfaces and rim. Herein, we report the syntheses of 2-pyridylcorannulene and its cyclopalladated complex. Its expanded π-system and columnar self-assembly in the crystal state were revealed by NMR and UV-vis spectroscopies, ESI-TOF mass spectrometry and single-crystal X-ray analysis. PMID:23338944

  9. Organization of columnar inputs in the third optic ganglion of a highly visual crab.

    PubMed

    Bengochea, Mercedes; Berón de Astrada, Martín

    2014-01-01

    Motion information provides essential cues for a wide variety of animal behaviors such as mate, prey, or predator detection. In decapod crustaceans and pterygote insects, visual codification of object motion is associated with visual processing in the third optic neuropile, the lobula. In this neuropile, tangential neurons collect motion information from small field columnar neurons and relay it to the midbrain where behavioral responses would be finally shaped. In highly ordered structures, detailed knowledge of the neuroanatomy can give insight into their function. In spite of the relevance of the lobula in processing motion information, studies on the neuroarchitecture of this neuropile are scant. Here, by applying dextran-conjugated dyes in the second optic neuropile (the medulla) of the crab Neohelice, we mass stained the columnar neurons that convey visual information into the lobula. We found that the arborizations of these afferent columnar neurons lie at four main lobula depths. A detailed examination of serial optical sections of the lobula revealed that these input strata are composed of different number of substrata and that the strata are thicker in the centre of the neuropile. Finally, by staining the different lobula layers composed of tangential processes we combined the present characterization of lobula input strata with the previous characterization of the neuroarchitecture of the crab's lobula based on reduced-silver preparations. We found that the third lobula input stratum overlaps with the dendrites of lobula giant tangential neurons. This suggests that columnar neurons projecting from the medulla can directly provide visual input to the crab's lobula giant neurons. PMID:24929118

  10. Organization of columnar inputs in the third optic ganglion of a highly visual crab.

    PubMed

    Bengochea, Mercedes; Berón de Astrada, Martín

    2014-01-01

    Motion information provides essential cues for a wide variety of animal behaviors such as mate, prey, or predator detection. In decapod crustaceans and pterygote insects, visual codification of object motion is associated with visual processing in the third optic neuropile, the lobula. In this neuropile, tangential neurons collect motion information from small field columnar neurons and relay it to the midbrain where behavioral responses would be finally shaped. In highly ordered structures, detailed knowledge of the neuroanatomy can give insight into their function. In spite of the relevance of the lobula in processing motion information, studies on the neuroarchitecture of this neuropile are scant. Here, by applying dextran-conjugated dyes in the second optic neuropile (the medulla) of the crab Neohelice, we mass stained the columnar neurons that convey visual information into the lobula. We found that the arborizations of these afferent columnar neurons lie at four main lobula depths. A detailed examination of serial optical sections of the lobula revealed that these input strata are composed of different number of substrata and that the strata are thicker in the centre of the neuropile. Finally, by staining the different lobula layers composed of tangential processes we combined the present characterization of lobula input strata with the previous characterization of the neuroarchitecture of the crab's lobula based on reduced-silver preparations. We found that the third lobula input stratum overlaps with the dendrites of lobula giant tangential neurons. This suggests that columnar neurons projecting from the medulla can directly provide visual input to the crab's lobula giant neurons.

  11. Protective role of cactus cladodes extract on sodium dichromate-induced testicular injury and oxidative stress in rats.

    PubMed

    Hfaiedh, Mbarka; Brahmi, Dalel; Zourgui, Lazhar

    2014-06-01

    Cactus (Opuntia ficus-indica) is a xerophyte plant that belongs to the Cactaceae family. The present study was designed to investigate the possible protective effects of cactus cladodes extract (CCE) on sodium dichromate-induced testis damage in adult male Wistar rats. For this purpose, CCE at a dose of 100 mg/kg was orally administrated, followed by 10 mg/kg sodium dichromate (intraperitoneal injection). After 40 days of treatment, the rats were sacrificed, and the testes were excised for histological, lipid peroxidation (LPO), and antioxidant enzyme analyses. Sodium dichromate treatment significantly (P<0.01) decreased the body, testis, and accessory sex organ weights, sperm count and motility, and serum testosterone level. In addition, histological analysis revealed pronounced morphological alterations with tubular necrosis and reduction in the number of gametes in the lumen of the seminiferous tubules of sodium dichromate-intoxicated rats. Furthermore, exposure to sodium dichromate significantly (P<0.01) increased LPO level and decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities in testis. Interestingly, pretreatment with CCE significantly (P<0.01) restored the serum testosterone level, sperm count, and motility to the levels of the control group. Moreover, CCE administration was capable of reducing the elevated level of LPO and significantly (P<0.01) increased SOD, CAT, and GPx activities in testis. Cactus cladodes supplementation minimized oxidative damage and reversed the impairment of spermatogenesis and testosterone production induced by sodium dichromate in the rat testis.

  12. Protective role of cactus cladodes extract on sodium dichromate-induced testicular injury and oxidative stress in rats.

    PubMed

    Hfaiedh, Mbarka; Brahmi, Dalel; Zourgui, Lazhar

    2014-06-01

    Cactus (Opuntia ficus-indica) is a xerophyte plant that belongs to the Cactaceae family. The present study was designed to investigate the possible protective effects of cactus cladodes extract (CCE) on sodium dichromate-induced testis damage in adult male Wistar rats. For this purpose, CCE at a dose of 100 mg/kg was orally administrated, followed by 10 mg/kg sodium dichromate (intraperitoneal injection). After 40 days of treatment, the rats were sacrificed, and the testes were excised for histological, lipid peroxidation (LPO), and antioxidant enzyme analyses. Sodium dichromate treatment significantly (P<0.01) decreased the body, testis, and accessory sex organ weights, sperm count and motility, and serum testosterone level. In addition, histological analysis revealed pronounced morphological alterations with tubular necrosis and reduction in the number of gametes in the lumen of the seminiferous tubules of sodium dichromate-intoxicated rats. Furthermore, exposure to sodium dichromate significantly (P<0.01) increased LPO level and decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities in testis. Interestingly, pretreatment with CCE significantly (P<0.01) restored the serum testosterone level, sperm count, and motility to the levels of the control group. Moreover, CCE administration was capable of reducing the elevated level of LPO and significantly (P<0.01) increased SOD, CAT, and GPx activities in testis. Cactus cladodes supplementation minimized oxidative damage and reversed the impairment of spermatogenesis and testosterone production induced by sodium dichromate in the rat testis. PMID:24752970

  13. White bass Morone chrysops is less susceptible than its hybrid to experimental infection with Flavobacterium columnare.

    PubMed

    Fuller, S Adam; Farmer, Bradley D; Beck, Benjamin H

    2014-04-23

    Hybrid striped bass (HSB) and white bass (WB) were evaluated for their susceptibility to Flavobacterium columnare, the causative agent of columnaris disease, in 3 fundamental studies. In the first experiment, we determined whether columnaris disease could be developed by experimental challenge in HSB. This challenge consisted of 3 levels of F. columnare (10, 30, and 60 ml volumes) determined to be 2.25 × 10(7), 6.75 × 10(7), and 1.35 × 10(8) CFU ml(-1), respectively. Each treatment group exhibited significantly different survival rates: 0, 3.3, and 13.3% in the 60, 30, and 10 ml groups, respectively. In Expt 2, using the 30 ml dose, both HSB and WB had a 0% survival rate, with WB taking significantly longer to reach 100% mortality. In Expt 3, using the 10 ml dose, no HSB survived, whereas 33% of WB survived (p < 0.0001). Compared to controls, HSB treated with 10 ml showed extensive gill damage at 24 h, which could have contributed to the higher mortality observed in HSB; in contrast, WB gills showed noticeably less damage. From these series of experiments, it is clear that HSB are more sensitive to F. columnare, having lower survival and more extensive histological damage compared to WB following challenge. PMID:24781793

  14. Rock Cracking Indices for Improved Tunnel Support Design: A Case Study for Columnar Jointed Rock Masses

    NASA Astrophysics Data System (ADS)

    Feng, Xia-Ting; Hao, Xian-Jie; Jiang, Quan; Li, Shao-jun; Hudson, John A.

    2016-06-01

    Measurements indicate that the development of cracking is a key feature relating to the strength and collapse of a columnar jointed rock mass. In this context, a new support design method utilising rock cracking indices for columnar jointed rock mass under high stress is proposed to restrain the development of cracking in the surrounding rock mass. The method involves limiting the cracking evolution of the surrounding rock mass by designing the appropriate parameters and time of installation of the support system. Two indices are suggested: the allowable depth of the excavation damaged zone (EDZ); and the allowable damage extent of the rock mass in the EDZ. The method involves limiting the evolution of cracking in the surrounding rock mass by designing the parameters and time of installation of the support system. The support system should have a suitable stiffness and installation time so as to restrain the evolution of the depth and damage extent of the EDZ within the surrounding rock. Therefore, the depth and damage extent of the EDZ, as well as the axial stress in the anchor bolts, are calculated at different distances between the support location and the tunnel working face to find the appropriate stiffness and installation time of the support system. The method has been successfully adopted to determine the thickness of shotcrete, the arrangement and installation time of rockbolts, and other parameters, for five large diversion tunnels at the Baihetan hydropower station, China, which were excavated in columnar jointed rock masses.

  15. White bass Morone chrysops is less susceptible than its hybrid to experimental infection with Flavobacterium columnare.

    PubMed

    Fuller, S Adam; Farmer, Bradley D; Beck, Benjamin H

    2014-04-23

    Hybrid striped bass (HSB) and white bass (WB) were evaluated for their susceptibility to Flavobacterium columnare, the causative agent of columnaris disease, in 3 fundamental studies. In the first experiment, we determined whether columnaris disease could be developed by experimental challenge in HSB. This challenge consisted of 3 levels of F. columnare (10, 30, and 60 ml volumes) determined to be 2.25 × 10(7), 6.75 × 10(7), and 1.35 × 10(8) CFU ml(-1), respectively. Each treatment group exhibited significantly different survival rates: 0, 3.3, and 13.3% in the 60, 30, and 10 ml groups, respectively. In Expt 2, using the 30 ml dose, both HSB and WB had a 0% survival rate, with WB taking significantly longer to reach 100% mortality. In Expt 3, using the 10 ml dose, no HSB survived, whereas 33% of WB survived (p < 0.0001). Compared to controls, HSB treated with 10 ml showed extensive gill damage at 24 h, which could have contributed to the higher mortality observed in HSB; in contrast, WB gills showed noticeably less damage. From these series of experiments, it is clear that HSB are more sensitive to F. columnare, having lower survival and more extensive histological damage compared to WB following challenge.

  16. Immunohistochemical/histochemical double staining method in the study of the columnar metaplasia of the oesophagus.

    PubMed

    Cabibi, D; Giannone, A G; Mascarella, C; Guarnotta, C; Castiglia, M; Pantuso, G; Fiorentino, E

    2014-03-05

    Intestinal metaplasia in Barrett's oesophagus (BO) represents an important risk factor for oesophageal adenocarcinoma. Instead, few and controversial data are reported about the progression risk of columnar-lined oesophagus without intestinal metaplasia (CLO), posing an issue about its clinical management. The aim was to evaluate if some immunophenotypic changes were present in CLO independently of the presence of the goblet cells. We studied a series of oesophageal biopsies from patients with endoscopic finding of columnar metaplasia, by performing some immunohistochemical stainings (CK7, p53, AuroraA) combined with histochemistry (Alcian-blue and Alcian/PAS), with the aim of simultaneously assess the histochemical features in cells that shows an aberrant expression of such antigens. We evidenced a cytoplasmic expression of CK7 and a nuclear expression of Aurora A and p53,  both in goblet cells of BO and in non-goblet cells of CLO, some of which showing mild dysplasia. These findings suggest that some immunophenotypic changes are present in CLO and they can precede the appearance of the goblet cells or can be present independently of them, confirming the conception of BO as the condition characterized by any extention of columnar epithelium. This is the first study in which a combined immunohistochemical/histochemical method has been applied to Barrett pathology.

  17. Effects of Cactus Fiber on the Excretion of Dietary Fat in Healthy Subjects: A Double Blind, Randomized, Placebo-Controlled, Crossover Clinical Investigation

    PubMed Central

    Uebelhack, Ralf; Busch, Regina; Alt, Felix; Beah, Zhi-Ming; Chong, Pee-Win

    2014-01-01

    Background Cactus (Opuntia ficus-indica) fiber was shown to promote weight loss in a 3-month clinical investigation. As demonstrated by in vitro studies, cactus fiber binds to dietary fat and its use results in reduced absorption, which in turn leads to reduced energy absorption and ultimately the reduction of body weight. Objective The objective of our study was to elucidate the dietary fat binding capacity of cactus fiber through determination of fecal fat excretion in healthy volunteers. Subjects and Methods This clinical investigation was performed as a double-blind, randomized, placebo-controlled, crossover study in healthy subjects for a period of approximately 45 days. Twenty healthy volunteer subjects were randomized to receive cactus fiber or placebo, 2 tablets thrice daily with main meals. All subjects were provided with meals during the study period (except washout) according to a standardized meal plan, with 35% of daily energy need coming from fat. Two 24-hour feces samples were collected during both the baseline and treatment periods for analysis of the fat content. Results Cactus fiber showed an increased fecal fat excretion compared with placebo (mean [SD] = 15.79% [5.79%] vs 4.56% [3.09%]; P < 0.001). No adverse events were reported throughout the study period. Conclusions Cactus fiber has been shown to significantly promote fecal fat excretion in healthy adults. The results of our study support the hypothesis that cactus fiber helps in reducing body weight by binding to dietary fat and increasing its excretion, thus reducing dietary fat available for absorption. ClinicalTrials.gov identifier: NCT01590667. PMID:25067985

  18. Performance of goats fed on low quality veld hay supplemented with fresh spiny cactus (Opuntia megacantha) mixed with browse legumes hay in Zimbabwe.

    PubMed

    Gusha, Jacob; Halimani, Tinyiko Edward; Katsande, Simbarashe; Zvinorova, Plaxedis Ivy

    2014-10-01

    Nutrition is a major constraint in smallholder livestock production; hence, the use of alternative sources which are adaptive to long dry seasons is imperative. The study was conducted to establish options of improving nutrition and palatability and also to determine the performance of goats fed on cactus-browse hay as dry season supplements. Palatability and adequacy of nutrition was investigated using 32 castrated male goat kids. The kids were housed in individual metabolism cages for 84 days in a complete randomised design (CRD) with eight replicates for the four treatment diets. Daily experimental diet, basal diet and water intake were measured, and live mass was measured at weekly intervals. Daily diet intake was significantly different (P < 0.05) among treatments. Kids that were supplemented with cactus-Leucaena leucocephala meal (CLLM) consumed more than those on cactus-Acacia angustissima meal (CAAM), cactus-Gliricidia sepium meal (CGSM) and cactus-Pennisetum purpureum meal (CPPM) in that order. CGSM was not readily palatable as goat kids refused to take it when mixed with fresh cactus. Animals that were not supplemented with a source of nitrogen together with those that were supplemented with less palatable diet of CGSM lost weight significantly (P < 0.05) initially but gained weight slightly towards the end of the study. Significantly higher weight gains (P < 0.05) were observed in animals in CLLM and CAAM treatment. It was concluded that fresh cactus could be used to improve poor quality roughage intakes in goats, and therefore, there is need to promote its use in periods of feed deficit especially in smallholder sector. PMID:25023231

  19. Use of spineless cactus (Opuntia ficus indica f. inermis) for dairy goats and growing kids: impacts on milk production, kid's growth, and meat quality.

    PubMed

    Mahouachi, M; Atti, N; Hajji, H

    2012-01-01

    The objective of this study was to determine the effect of spineless cactus incorporation in food of dairy goats and growing kids on milk production and composition and on kid's growth and meat characteristics. Two experiments were conducted on Tunisian local goats. In the first, 30 females were divided into two groups; goats of Control group were reared on grazing pasture receiving indoor 0.5 kg of hay and 0.4 kg of concentrate. Goats for the second group (Cac-FL) were kept in feedlot and fed cactus ad libitum more 0.5 kg of hay and 0.4 kg of concentrate. In the second experiment, 14 kids were divided into 2 groups receiving 600 g of hay. The Control group received ad libitum a concentrate containing 130 g crude protein (CP) per kg of dry matter. The second group received cactus ad-libitum plus the half concentrate quantity of control one with 260 g CP/kg DM (Cactus). The daily milk production averaged 485 ml for Control group and 407 ml for Cac-FL one. The milk fat content was significantly higher for Control than Cac-FL group. In the second experiment, animals in Control and Cactus groups had similar growth rate. Carcass fat was significantly lower in Cactus than in the Control group. Cactus in the diet was associated with more C18:2 and conjugated linoleic acid as well as a higher proportion of PUFA than Control ones.

  20. Performance of goats fed on low quality veld hay supplemented with fresh spiny cactus (Opuntia megacantha) mixed with browse legumes hay in Zimbabwe.

    PubMed

    Gusha, Jacob; Halimani, Tinyiko Edward; Katsande, Simbarashe; Zvinorova, Plaxedis Ivy

    2014-10-01

    Nutrition is a major constraint in smallholder livestock production; hence, the use of alternative sources which are adaptive to long dry seasons is imperative. The study was conducted to establish options of improving nutrition and palatability and also to determine the performance of goats fed on cactus-browse hay as dry season supplements. Palatability and adequacy of nutrition was investigated using 32 castrated male goat kids. The kids were housed in individual metabolism cages for 84 days in a complete randomised design (CRD) with eight replicates for the four treatment diets. Daily experimental diet, basal diet and water intake were measured, and live mass was measured at weekly intervals. Daily diet intake was significantly different (P < 0.05) among treatments. Kids that were supplemented with cactus-Leucaena leucocephala meal (CLLM) consumed more than those on cactus-Acacia angustissima meal (CAAM), cactus-Gliricidia sepium meal (CGSM) and cactus-Pennisetum purpureum meal (CPPM) in that order. CGSM was not readily palatable as goat kids refused to take it when mixed with fresh cactus. Animals that were not supplemented with a source of nitrogen together with those that were supplemented with less palatable diet of CGSM lost weight significantly (P < 0.05) initially but gained weight slightly towards the end of the study. Significantly higher weight gains (P < 0.05) were observed in animals in CLLM and CAAM treatment. It was concluded that fresh cactus could be used to improve poor quality roughage intakes in goats, and therefore, there is need to promote its use in periods of feed deficit especially in smallholder sector.

  1. Lack of association between Flavobacterium columnare genomovar and virulence in hybrid tilapia Oreochromis niloticus (L.)×Oreochromis aureus (Steindachner).

    PubMed

    Shoemaker, C A; LaFrentz, B R

    2015-05-01

    Columnaris disease can be problematic in tilapia (Oreochromis spp.) production. An understanding of the pathogenesis and virulence of Flavobacterium columnare is needed to develop prevention strategies. The objective of this study was to determine the virulence of genetically defined isolates of F. columnare in sex-reversed hybrid tilapia, Oreochromis niloticus (L.)×O. aureus (Steindachner). A series of immersion challenge trials were performed using isolates of the five established genomovars of F. columnare: I, II, II-B, III and I/II. The mean per cent mortality of fish challenged with genomovar I, II and III isolates ranged from 0 to 100, 3.3-78 and 3.3-75%, respectively. The mean per cent mortality of fish challenged with genomovar II-B ranged from 35 to 96.7%, and the only genomovar I/II isolate tested caused no mortality. Contrary to previous work in other fish species, there did not appear to be an association between F. columnare genomovar and virulence in tilapia. The challenge model used resulted in acute mortality. An alternative challenge model was tested by cohabitating healthy fish with dead fish infected with F. columnare. This method resulted in rapid appearance of clinical signs and mortality, suggesting the potential for F. columnare to increase in virulence upon growth on/in a fish host. PMID:24909885

  2. Cavity and end effects on flow past cactus-shaped cylinders

    NASA Astrophysics Data System (ADS)

    Talley, Sharon; Mungal, Godfrey

    2002-11-01

    Motivation for this study is the saguaro cactus, which is a leafless cylindrical tree that grows in the Sonaron Desert of the United States. Saguaros have an average diameter of 0.5 m, and at the highest wind velocities in their natural habitat, they experience flows up to a Re of 10^6. These giant trees have longitudinal cavities that span the length of the trunk. Typical cavity depths have a cavity depth ratio (l/d - cavity depth divided by diameter of the stem) of 0.07. Experimental measurements of pressure distribution, unsteady drag and lift, and vortex shedding are performed in a low speed wind tunnel over a over a range of Reynolds numbers from 1 × 10^4 to 2 × 10^5. We compare cylinders that differ in their surface geometry: a smooth cylinder, sandpaper roughened cylinders (k_s/d = 1.74 × 10-3 and 8.41 × 10-3), and cylinders with different cavity depths (l/d of 0.035, 0.07, and 0.105). For each of the test cylinders, we examine the effects of flat and hemispherical ends on a free end while the other end is attached. The benefits of cavity depth and hemispherical ends will be discussed.

  3. Removing heavy metals in water: the interaction of cactus mucilage and arsenate (As (V)).

    PubMed

    Fox, Dawn I; Pichler, Thomas; Yeh, Daniel H; Alcantar, Norma A

    2012-04-17

    High concentrations of arsenic in groundwater continue to present health threats to millions of consumers worldwide. Particularly, affected communities in the developing world need accessible technologies for arsenic removal from drinking water. We explore the application of cactus mucilage, pectic polysaccharide extracts from Opuntia ficus-indica for arsenic removal. Synthetic arsenate (As (V)) solutions were treated with two extracts, a gelling extract (GE) and a nongelling extract (NE) in batch trials. The arsenic concentration at the air-water interface was measured after equilibration. The GE and NE treated solutions showed on average 14% and 9% increases in arsenic concentration at the air-water interface respectively indicating that the mucilage bonded and transported the arsenic to the air-water interface. FTIR studies showed that the -CO groups (carboxyl and carbonyl groups) and -OH (hydroxyl) functional groups of the mucilage were involved in the interaction with the arsenate. Mucilage activity was greater in weakly basic (pH 9) and weakly acidic (pH 5.5) pH. This interaction can be optimized and harnessed for the removal of arsenic from drinking water. This work breaks the ground for the application of natural pectic materials to the removal of anionic metallic species from water. PMID:22401577

  4. Closure Report for Corrective Action Unit 426: Cactus Spring Waste Trenches, Tonopah Test Range, Nevada

    SciTech Connect

    Dave Madsen

    1998-08-01

    This Closure Report provides the documentation for closure of the Cactus Spring Waste Trenches Corrective Action Unit (CAU) 426. The site is located on the Tonopah Test Range, approximately 225 kilometers northwest of Las Vegas, NV. CAU 426 consists of one corrective action site (CAS) which is comprised of four waste trenches. The trenches were excavated to receive solid waste generated in support of Operation Roller Coaster, primary the Double Tracks Test in 1963, and were subsequently backfilled. The Double Tracks Test involved use of live animals to assess the biological hazards associated with the nonnuclear detonation of plutonium-bearing devices. The Nevada Division of Environmental Protection approved Corrective Action Plan (CAP)which proposed ''capping'' methodology. The closure activities were completed in accordance with the approved CAP and consisted of constructing an engineered cover in the area of the trenches, constructing/planting a vegetative cover, installing a perimeter fence and signs, implementing restrictions on future use, and preparing a Post-Closure Monitoring Plan.

  5. Cactus pear extracts induce reactive oxygen species production and apoptosis in ovarian cancer cells.

    PubMed

    Feugang, Jean M; Ye, Fei; Zhang, David Y; Yu, Yanhong; Zhong, Mei; Zhang, Sui; Zou, Changping

    2010-01-01

    The protective effect of natural products such as fruits and vegetables against cancer has attracted great attention because of their fewer side effects and therefore, potentially greater safety. We have previously reported that cactus pear mixture aqueous extract (CME) reduces gynecologic cancer cells growth by inducting apoptosis. This study aimed to elucidate the cellular pathway(s) triggered by CME in cancer cells. Normal, immortalized ovarian and ovarian cancer cells (OVCA420, SKOV3) were treated with 5 and 10% CME. After 2 days of treatment, immortalized cells treated with 10% CME accumulated more ROS than untreated cells, whereas cancer cells cultured with 5% and 10% CME exhibited a dramatic increase of reactive oxygen species (ROS). Greater levels of DNA fragmentation, together with a perturbed expression of apoptotic-related (Bax, Bad, caspase 3, Bcl2, p53, and p21) and ROS-sensitive (NF-kappaB, c-jun/c-fos) genes were observed in the treated cancer cells. After three days of treatment, the NF-kappaB and p-/SAPK/JNK expressions were decreased, whereas p-AKT was upregulated. The CME significantly induced apoptosis in cancer cells. The results suggest an inhibitory effect of Arizona CME on cancer cell growth through the accumulation of intracellular ROS, which may activate a cascade of reactions leading to the apoptosis. PMID:20574930

  6. Micromorphology of cactus-pear (Opuntia ficus-indica (L.) Mill) cladodes based on scanning microscopies.

    PubMed

    Ben Salem-Fnayou, Asma; Zemni, Hassène; Nefzaoui, Ali; Ghorbel, Abdelwahed

    2014-01-01

    Cladode ultrastructural features of two prickly and two spineless Opuntia ficus-indica cultivars were examined using environmental scanning electron and atomic force microscopies. Observations focused on cladode as well as spine and glochid surface micromorphologies. Prickly cultivars were characterized by abundant cracked epicuticular wax deposits covering the cladode surface, with an amorphous structure as observed by AFM, while less abundant waxy plates were observed by ESEM on spineless cultivar cladodes. Further AFM observations allowed a rough granular and crystalloid epicuticular wax structure to be distinguished in spineless cultivars. Regarding spine micromorphology, prickly cultivars had strong persistent spines, observed by ESEM as a compact arrangement of oblong epidermal cells with a rough granular structure. However, deciduous spines in spineless cultivars had a broken transversely fissured epidermis covering a parallel arrangement of fibres. Through AFM, the deciduous spine surface presented an irregular hilly and smooth microrelief while persistent spines exhibited rough helical filamentous prints. ESEM and AFM studies of cladode surfaces from prickly and spineless cactus pear cultivars revealed valuable micro-morphological details that ought to be extended to a large number of O. ficus-indica cultivars.

  7. Genetic and chemical diversity in seeds of cactus mandacaru (Cereus sp.) from two edaphoclimatic regions contrasting.

    PubMed

    Bevilaqua, Maycon R R; Santana Filho, Arquimedes P; Mangolin, Claudete A; Oliveira, Arildo J B; Machado, Maria De Fátima P S

    2015-01-01

    The purpose of this study was to evaluate the chemical, physiological and genetic differences in seeds of cactus of the Cereus genus (mandacaru) cultivated in the Northeast (Picos, State of Piauí) and Southern (Maringá, State of Paraná) regions of Brazil. Over a period of eight days, temperatures of 25°C and 30°C were equally efficient for the germination of all the seeds. Oleic acid (C18:1) was the most common fatty acid found in the seeds collected in the Southern (41%) and Northeast (45.5%) regions. The analysis of lipases indicated that seeds from Maringá have high mean observed and expected heterozygosities and that seeds from Picos have a higher number of alleles per loci. Therefore, the seeds of mandacaru from the semiarid region of Northeast as well as the seeds from the South (the two contrasting regions of Brazil) are promising with regards to the preservation of the biodiversity in the genome of mandacaru. The low genetic identity between mandacaru seeds from Maringá and Picos at Lipase-5 locus analysis (I = 0.77) suggests that the mandacaru plants from Maringá and Picos may correspond to two species: C. peruvianus and C. jamacaru, respectively.

  8. Semiochemicals from ex situ abiotically stressed cactus tissue: a contributing role of fungal spores?

    PubMed

    Beck, John J; Baig, Nausheena; Cook, Daniel; Mahoney, Noreen E; Marsico, Travis D

    2014-12-24

    Semiochemicals play a central role in communication between plants and insects, such as signaling the location of a suitable host. Fungi on host plants can also play an influential role in communicating certain plant vulnerabilities to an insect. The spiroketal conophthorin is an important semiochemical produced by developing fungal spores. Spiroketals are also used as signals for scolytid communication. Plants and fungi are known to emit varying volatile profiles under biotic and abiotic stress. This paper reports distinctive temporal-volatile profiles from three abiotic treatments, room temperature (control), -15 °C (cold), and -15 °C to room temperature (shock), of cactus tissue plugs. Volatiles from the three treatments included monoterpenes from control plugs, compounds of varying classes and origin at later stages for cold plugs, and known semiochemicals, including spiroketals, at later stages for shock plugs. The results highlight several important findings: a unique tissue source of the spiroketals; abiotic cold-shock stress is indicated as the cause of spiroketal production; and, given previous findings of spirogenesis, fungal spore involvement is a probable biosynthetic origin of the spiroketals. These findings suggest an important role of fungal volatiles as signaling plant vulnerability to insects.

  9. Hierarchical structures of cactus spines that aid in the directional movement of dew droplets.

    PubMed

    Malik, F T; Clement, R M; Gethin, D T; Kiernan, M; Goral, T; Griffiths, P; Beynon, D; Parker, A R

    2016-08-01

    Three species of cactus whose spines act as dew harvesters were chosen for this study: Copiapoa cinerea var. haseltoniana, Mammillaria columbiana subsp. yucatanensis and Parodia mammulosa and compared with Ferocactus wislizenii whose spines do not perform as dew harvesters. Time-lapse snapshots of C. cinerea showed movement of dew droplets from spine tips to their base, even against gravity. Spines emanating from one of the areoles of C. cinerea were submerged in water laced with fluorescent nanoparticles and this particular areole with its spines and a small area of stem was removed and imaged. These images clearly showed that fluorescent water had moved into the stem of the plant. Lines of vascular bundles radiating inwards from the surface areoles (from where the spines emanate) to the core of the stem were detected using magnetic resonance imaging, with the exception of F. wislizenii that does not harvest dew on its spines. Spine microstructures were examined using SEM images and surface roughness measurements (Ra and Rz) taken of the spines of C. cinerea It was found that a roughness gradient created by tapered microgrooves existed that could potentially direct surface water from a spine tip to its base.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'.

  10. Closure Report for Corrective Action Unit 426: Cactus Spring Waste Trenches, Tonopah Test Range, Nevada

    SciTech Connect

    Dave D. Madsen

    1998-08-08

    This closure report provides the documentation for closure of the Cactus Spring Waste Trenches Corrective Action Unit (CAU) 426. The site is located on the Tonopah Test Range,approximately 225 kilometers (140 miles) northwest of Las Vegas, Nevada. CAU 426 consists of one Corrective Action Site which is comprised of four waste trenches. The trenches were excavated to receive solid waste generated in support of Operation Roller Coaster, primarily the Double Tracks Test in 1963, and were subsequently backfilled. The Double Tracks Test involved the use of live animals to assess the biological hazards associated with the non-nuclear detonation of plutonium-bearing devices (i.e., inhalation uptake of plutonium aerosol) (DOE, 1996). The remedial alternative proposed Nevada Division of Environmental Protection proposed the capping method. The closure activities were completed in accordance with the approved Corrective Action Plan and consisted of constructing an engineered cover in the ar ea of the trenches, constructing/planning a vegetative cover, installing a perimeter fence and signs, implementing restrictions on future use, and preparing a post-closure monitoring plan. Closure activities for CAU 426 have been completed in accordance with the Nevada Division of Environmental Protection approved Corrective Action Plan as documented in this Closure Report.

  11. Resolving a Prickly Situation: Involving Stakeholders in Invasive Cactus Management in South Africa.

    PubMed

    Novoa, Ana; Kaplan, Haylee; Wilson, John R U; Richardson, David M

    2016-05-01

    The regulation and management of alien species can be contentious, particularly when the stakeholders who benefit from alien species are different from those who suffer the costs. We propose a consultative process involving relevant stakeholders in invasive species management decisions. The process involves (1) the identification of relevant stakeholders, (2) assessing their perceptions, (3) enhancing interaction between stakeholders, (4) assessing changes in stakeholders' perceptions following interactions with other stakeholders, and (5) developing management recommendations in collaboration with stakeholders. We demonstrate the application of the process using the family Cactaceae ('cacti') in South Africa. Many species of cacti have been introduced to the country over the past two centuries, mostly for horticulture, food and fodder, and hundreds of other species have been introduced in the past few decades (or are likely to be introduced soon) for horticulture. Using the proposed process enabled the negotiation and participation of all stakeholders in decision making and helped minimize contentious situations by clarifying stakeholder's beliefs and exploring consensus solutions. Consequently, management objectives were broadly supported by all stakeholders. These results will be included in a national cactus management strategy for South Africa.

  12. Polymorphic microsatellite markers for the rare and endangered cactus Uebelmannia pectinifera (Cactaceae) and its congeneric species.

    PubMed

    Moraes, E M; Cidade, F W; Silva, G A R; Machado, M C

    2014-12-04

    The cactus genus Uebelmannia includes 3 narrow endemic species associated with rocky savanna habitats in eastern South America. Because of their rarity and illegal over-collection, all of these species are endangered. Taxonomic uncertainties resulting from dramatic local variation in morphology within Uebelmannia species preclude effective conservation efforts, such as the reintroduction or translocation of plants, to restore declining populations. In this study, we developed and characterized 18 perfect, dinucleotide simple-sequence repeat markers for U. pectinifera, the most widely distributed species in the genus, and tested the cross-amplification of these markers in the remaining congeneric species and subspecies. All markers were polymorphic in a sample from 2 U. pectinifera populations. The effective number of alleles ranged from 1.6 to 8.7, with an average per population of 3.3 (SE ± 0.30) and 4.5 (SE ± 0.50). Expected heterozygosity ranged from 0.375 to 0.847 and 8-10 loci showed departures from Hardy- Weinberg equilibrium in the analyzed populations. Based on the observed polymorphism level of each marker, as well as the analysis of null allele presence and evidence of amplification of duplicate loci, a subset of 12 loci can be used as reliable markers to investigate the genetic structure, diversity, and species limits of the Uebelmannia genus.

  13. Genetic and chemical diversity in seeds of cactus mandacaru (Cereus sp.) from two edaphoclimatic regions contrasting.

    PubMed

    Bevilaqua, Maycon R R; Santana Filho, Arquimedes P; Mangolin, Claudete A; Oliveira, Arildo J B; Machado, Maria De Fátima P S

    2015-01-01

    The purpose of this study was to evaluate the chemical, physiological and genetic differences in seeds of cactus of the Cereus genus (mandacaru) cultivated in the Northeast (Picos, State of Piauí) and Southern (Maringá, State of Paraná) regions of Brazil. Over a period of eight days, temperatures of 25°C and 30°C were equally efficient for the germination of all the seeds. Oleic acid (C18:1) was the most common fatty acid found in the seeds collected in the Southern (41%) and Northeast (45.5%) regions. The analysis of lipases indicated that seeds from Maringá have high mean observed and expected heterozygosities and that seeds from Picos have a higher number of alleles per loci. Therefore, the seeds of mandacaru from the semiarid region of Northeast as well as the seeds from the South (the two contrasting regions of Brazil) are promising with regards to the preservation of the biodiversity in the genome of mandacaru. The low genetic identity between mandacaru seeds from Maringá and Picos at Lipase-5 locus analysis (I = 0.77) suggests that the mandacaru plants from Maringá and Picos may correspond to two species: C. peruvianus and C. jamacaru, respectively. PMID:26131634

  14. Combining Ferric Salt and Cactus Mucilage for Arsenic Removal from Water.

    PubMed

    Fox, Dawn I; Stebbins, Daniela M; Alcantar, Norma A

    2016-03-01

    New methods to remediate arsenic-contaminated water continue to be studied, particularly to fill the need for accessible methods that can significantly impact developing communities. A combination of cactus mucilage and ferric (Fe(III)) salt was investigated as a flocculation-coagulation system to remove arsenic (As) from water. As(V) solutions, ferric nitrate, and mucilage suspensions were mixed and left to stand for various periods of time. Visual and SEM observations confirmed the flocculation action of the mucilage as visible flocs formed and settled to the bottom of the tubes within 3 min. The colloidal suspensions without mucilage were stable for up to 1 week. Sample aliquots were tested for dissolved and total arsenic by ICP-MS and HGAFS. Mucilage treatment improved As removal (over Fe(III)-only treatment); the system removed 75-96% As in 30 min. At neutral pH, removal was dependent on Fe(III) and mucilage concentration and the age of the Fe(III) solution. The process is fast, achieving maximum removal in 30 min, with the majority of As removed in 10-15 min. Standard jar tests with 1000 μg/L As(III) showed that arsenic removal and settling rates were pH-dependent; As removal was between 52% (high pH) and 66% (low pH). PMID:26824141

  15. Resolving a Prickly Situation: Involving Stakeholders in Invasive Cactus Management in South Africa.

    PubMed

    Novoa, Ana; Kaplan, Haylee; Wilson, John R U; Richardson, David M

    2016-05-01

    The regulation and management of alien species can be contentious, particularly when the stakeholders who benefit from alien species are different from those who suffer the costs. We propose a consultative process involving relevant stakeholders in invasive species management decisions. The process involves (1) the identification of relevant stakeholders, (2) assessing their perceptions, (3) enhancing interaction between stakeholders, (4) assessing changes in stakeholders' perceptions following interactions with other stakeholders, and (5) developing management recommendations in collaboration with stakeholders. We demonstrate the application of the process using the family Cactaceae ('cacti') in South Africa. Many species of cacti have been introduced to the country over the past two centuries, mostly for horticulture, food and fodder, and hundreds of other species have been introduced in the past few decades (or are likely to be introduced soon) for horticulture. Using the proposed process enabled the negotiation and participation of all stakeholders in decision making and helped minimize contentious situations by clarifying stakeholder's beliefs and exploring consensus solutions. Consequently, management objectives were broadly supported by all stakeholders. These results will be included in a national cactus management strategy for South Africa. PMID:26935429

  16. Hierarchical structures of cactus spines that aid in the directional movement of dew droplets.

    PubMed

    Malik, F T; Clement, R M; Gethin, D T; Kiernan, M; Goral, T; Griffiths, P; Beynon, D; Parker, A R

    2016-08-01

    Three species of cactus whose spines act as dew harvesters were chosen for this study: Copiapoa cinerea var. haseltoniana, Mammillaria columbiana subsp. yucatanensis and Parodia mammulosa and compared with Ferocactus wislizenii whose spines do not perform as dew harvesters. Time-lapse snapshots of C. cinerea showed movement of dew droplets from spine tips to their base, even against gravity. Spines emanating from one of the areoles of C. cinerea were submerged in water laced with fluorescent nanoparticles and this particular areole with its spines and a small area of stem was removed and imaged. These images clearly showed that fluorescent water had moved into the stem of the plant. Lines of vascular bundles radiating inwards from the surface areoles (from where the spines emanate) to the core of the stem were detected using magnetic resonance imaging, with the exception of F. wislizenii that does not harvest dew on its spines. Spine microstructures were examined using SEM images and surface roughness measurements (Ra and Rz) taken of the spines of C. cinerea It was found that a roughness gradient created by tapered microgrooves existed that could potentially direct surface water from a spine tip to its base.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. PMID:27354735

  17. Resolving a Prickly Situation: Involving Stakeholders in Invasive Cactus Management in South Africa

    NASA Astrophysics Data System (ADS)

    Novoa, Ana; Kaplan, Haylee; Wilson, John R. U.; Richardson, David M.

    2016-05-01

    The regulation and management of alien species can be contentious, particularly when the stakeholders who benefit from alien species are different from those who suffer the costs. We propose a consultative process involving relevant stakeholders in invasive species management decisions. The process involves (1) the identification of relevant stakeholders, (2) assessing their perceptions, (3) enhancing interaction between stakeholders, (4) assessing changes in stakeholders' perceptions following interactions with other stakeholders, and (5) developing management recommendations in collaboration with stakeholders. We demonstrate the application of the process using the family Cactaceae (`cacti') in South Africa. Many species of cacti have been introduced to the country over the past two centuries, mostly for horticulture, food and fodder, and hundreds of other species have been introduced in the past few decades (or are likely to be introduced soon) for horticulture. Using the proposed process enabled the negotiation and participation of all stakeholders in decision making and helped minimize contentious situations by clarifying stakeholder's beliefs and exploring consensus solutions. Consequently, management objectives were broadly supported by all stakeholders. These results will be included in a national cactus management strategy for South Africa.

  18. Disruption rates for one vulnerable soil in Organ Pipe Cactus National Monument, Arizona, USA

    USGS Publications Warehouse

    Webb, Robert H.; Esque, Todd C.; Nussear, Kenneth E.; Sturm, Mark

    2013-01-01

    Rates of soil disruption from hikers and vehicle traffic are poorly known, particularly for arid landscapes. We conducted an experiment in Organ Pipe Cactus National Monument (ORPI) in western Arizona, USA, on an air-dry very fine sandy loam that is considered to be vulnerable to disruption. We created variable-pass tracks using hikers, an all-terrain vehicle (ATV), and a four-wheel drive vehicle (4WD) and measured changes in cross-track topography, penetration depth, and bulk density. Hikers (one pass = 5 hikers) increased bulk density and altered penetration depth but caused minimal surface disruption up to 100 passes; a minimum of 10 passes were required to overcome surface strength of this dry soil. Both ATV and 4WD traffic significantly disrupted the soil with one pass, creating deep ruts with increasing passes that rendered the 4WD trail impassable after 20 passes. Despite considerable soil loosening (dilation), bulk density increased in the vehicle trails, and lateral displacement created berms of loosened soil. This soil type, when dry, can sustain up to 10 passes of hikers but only one vehicle pass before significant soil disruption occurs; greater disruption is expected when soils are wet. Bulk density increased logarithmically with applied pressure from hikers, ATV, and 4WD.

  19. Vascular Plant and Vertebrate Inventory of Organ Pipe Cactus National Monument

    USGS Publications Warehouse

    Schmidt, Cecilia A.; Powell, Brian F.; Halvorson, William L.

    2007-01-01

    Executive Summary We summarized inventory and monitoring efforts for plants and vertebrates at Organ Pipe Cactus National Monument (NM) in Arizona. We used data from previous research to compile complete species lists for the monument and to assess inventory completeness. There have been 1,031 species of plants and vertebrates observed at the monument. Most of the species on the list are documented by voucher specimens. There are 59 non-native species established in the monument: one mammal, three birds, and 55 non-native plants. Most non-native plant species were first recorded along roads. In each taxon-specific chapter, we highlight areas that contribute disproportionately to species richness or that have unique species for the monument. Of particular importance are Quitobaquito Springs and Pond, which are responsible for the monument having one of the highest number of bird species in the Sonoran Desert Network of parks. Quitobaquito also contains the only fish in the monument, the endangered Quitobaquito pupfish (Cyprinodon eremus). Other important resources for the plants and vertebrates include the xeroriparian washes (e.g., Alamo Canyon) and the Ajo Mountains. Based on the review of past studies, we believe the inventories of vascular plants and vertebrates are nearly complete and that the monument has one of the most complete inventories of any unit in the Sonoran Desert Network.

  20. Retrieval of absorptive gas columnar amounts using atmospheric hyper-spectral irradiance measurements within visible spectrum

    NASA Astrophysics Data System (ADS)

    Xu, Hua; Li, Zhengqiang; Li, Donghui; Xie, Yisong; Li, Kaitao; Qie, Lili; Zhang, Ying; Chen, Xingfeng; Zheng, Xiaobin; Li, Xin; Zhang, Yanna

    2015-10-01

    A hyper spectral ground-based instrument named Atmosphere-Surface Radiation Automatic Instrument (ASRAI) has been developed for the purpose of in-situ calibration of satellites. The apparatus has both upward and downward looking views, and thus can observe both the atmosphere and land surface. The solar transmitted irradiance can be derived from the measured full spectral irradiance and diffused spectral irradiance of atmosphere within visible spectrum (0.4-1.0μm). A method similar to that of King et al. which originally intended to apply to multi-wavelength measurements, is adopted to determine absorptive gaseous columnar amount from hyper spectrum. The solar irradiance at top of atmosphere and absorption coefficients of water vapor (H2O), ozone (O3), oxygen (O2) and nitrogen dioxide (NO2) are recalculated at an instrumental spectral resolution by convolution method. Based on the gaseous characteristics of absorption, the total columnar amounts of water vapor and oxygen are first inferred from solar transmitted irradiance at strong absorption wavelength of 0.934μm and 0.763μm respectively. The total columnar amounts of ozone and nitrogen dioxide, together with aerosol optical depth, are determined by a nonlinear least distance fitting method which minimizes a χ2 statistic to obtain optimal solutions. ASRAI was deployed for observation in Dunhuang site in China in August of 2014. Our results demonstrate that the algorithm is reasonable. Although the validation is preliminary, the hyper spectrum measured by ASRAI exhibits good ability to retrieve the abundance of absorptive gases and aerosols.

  1. Optical response of columnar TiO{sub 2}:Co on Si substrate

    SciTech Connect

    Anggraeni, G. P.; Saripudin, A.; Rusydi, A.; Darma, Y.

    2015-09-30

    Vertically arranged columnar TiO{sub 2}:Co structure has been deposited on Si (100) substrate using the metal organic chemical vapor deposition (MOCVD) technique. SEM images confirm the columnar structure of the TiO{sub 2}:Co layer on Si (100). Concentration of the Co dopant has been defined by means of the energy dispersive x-ray (EDX) spectra. Co concentrations are varied at 0.18, 0.33, and 0.68 at. % using pure TiO{sub 2} as the reference. X-ray diffraction (XRD) spectra show that the TiO{sub 2}:Co layer have a rutile phase. Further analysis of this structure has been performed by using room temperature spectroscopic ellipsometry (SE) measurements in the energy range of 0.5 - 6.5 eV. This optical response shows the unique feature of significantly high density fringe especially below the band gap energy region (lower than 3.3 eV) in contrast to the conventional TiO{sub 2} thin film structure. This unique feature is interpreted as a dominant contribution of the vertical interfaces at columnar boundaries towards reflected light from the sample. The evolution of Ψ and Δ will be discussed as the function of Co concentration and some optical properties will be extracted after reasonably well data fitting by multilayer modelling. Furthermore, by comparing the SE data from different measurement orientations, it has been shown that TiO{sub 2}:Co tends to be anisotropic. This study enables us to further evaluate structural properties through optical responses given by SE measurement.

  2. The Solar Vortex: Electric Power Generation using Anchored, Buoyancy-Induced Columnar Vortices

    NASA Astrophysics Data System (ADS)

    Glezer, Ari

    2015-04-01

    Naturally-occurring, buoyancy-driven columnar vortices (``dust devils'') that are driven by the instability of thermally stratified air layers and sustained by the entrainment of ground- heated air, occur spontaneously in the natural environment with core diameters of 1-50 m and heights up to 1 km. These vortices convert low-grade waste heat in the air layer overlying the warm surface into a solar-induced wind with significant kinetic energy. Unlike dust devil vortices that are typically free to wander laterally, the Solar Vortex (SoV) is deliberately triggered and anchored within a cylindrical domain bounded by an azimuthal array of stationary ground-mounted vertical vanes and sustained by continuous entrainment of the ground-heated air through these vanes. The mechanical energy of the anchored vortex is exploited for power generation by coupling the vortex to a vertical-axis turbine. This simple, low-cost electric power generating unit is competitive in cost, intermittency, and capacity factor with traditional solar power technologies. The considerable kinetic energy of the vortex column cannot be explained by buoyancy alone, and the fundamental mechanisms associated with the formation, evolution, and dynamics of an anchored, buoyancy-driven columnar vortex were investigated experimentally and numerically with specific emphasis on flow manipulation for increasing the available kinetic energy and therefore the generated power. These investigations have also considered the dependence of the vortex scaling and strength on the thermal resources and on the flow enclosure in the laboratory and in the natural environment. Preliminary outdoor tests of a two-meter scale prototype successfully demonstrated the ability to engender and anchor a columnar vortex using only solar radiation and couple the flow to a vertical axis wind turbine. A kilowatt-scale outer door prototype will be tested during the summer of 2015.

  3. Experimental Study of Disruption of Columnar Grains During Rapid Solidification in Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Manogharan, Guha; Yelamanchi, Bharat; Aman, Ronald; Mahbooba, Zaynab

    2016-03-01

    Over the years, many studies have been conducted to study and analyze the grain structures of metal alloys during additive manufacturing to improve mechanical properties. In particular, columnar grains are observed predominantly during rapid solidification of molten metal. This leads to lower mechanical properties and requires expensive secondary heat-treatment processes. This study is aimed at disrupting the formation of columnar grain growth during rapid solidification using ultrasonic vibration and analyzes the effects on grain structure and mechanical properties. A gas-metal arc welder mounted on a Rep-Rap-based low-cost metal 3 Dimension printer was used to deposit ER70S-6 mild steel layers on a plate. A contact-type ultrasonic transducer with a control system to vary the frequency and power of the vibration was used. The effects of ultrasonic vibration were determined from the statistical analysis of microstructure and micro-indentation techniques on the deposited layer and heat-affected zone. It was found that both frequency and interaction between frequency and power had significant impact on the refinement of average grain size up to 10.64% and increased the number of grains by approximately 41.78%. Analysis of micro-indentation tests showed that there was an increase of approximately 14.30% in micro-hardness due to the applied frequency during rapid solidification. A pole diagram shows that application of vibration causes randomization of grain orientation. Along with the results from this study, further efforts in modeling and experimentation of multi-directional vibrations would lead to a better understanding of disrupting columnar grains in applications that use mechanical vibrations, such as welding, directed energy deposition, brazing, etc.

  4. Cumulative mechanical moments and microstructure deformation induced by growth shape in columnar solidification.

    PubMed

    Billia, Bernard; Bergeon, Nathalie; Thi, Henri Nguyen; Jamgotchian, Haïk; Gastaldi, Joseph; Grange, Gérard

    2004-09-17

    The dynamical interaction between columnar interface microstructure and self-stress, resulting in unforeseen mechanical deformation phenomena, is brought to light by means of in situ and real-time synchrotron x-ray topography during directional solidification of dilute aluminum alloys. Beyond long-known local mechanical stresses, global mechanical constraints are found to be active. In particular, column rotation results from deformation caused by the mechanical moments associated with the very growth shape, namely, the cumulative torque acting together with the cumulative bending moment under gravity. A basic model allowing for a qualitative explanation of the observed distinctive features of the self-stress effects on microstructure dynamics is proposed.

  5. Stable Isotopic Variations in Columnar Cacti: are Responses to Climate Recorded in Spines?

    NASA Astrophysics Data System (ADS)

    English, N. B.; Dettman, D. L.; Williams, D. G.

    2004-12-01

    The behavior of the North American monsoon (NAM), particularly with respect to times of continental drought and its relationship to the Pacific-North American (PNA) teleconnection pattern and the El Nino/Southern Oscillation (ENSO) is of great interest to paleoclimatologists and water managers. Long-term instrumental precipitation and tree ring records in the southwestern United States and northwestern Mexico at low elevations are sparse and this has hindered research on NAM variability at interannual timescales. Saguaro cacti (Carnegiea gigantea) and other columnar cacti in North and South America are long-lived and have the potential to record climate variability on land with high temporal and spatial resolution. The vertical sequence of spines on the saguaro's exterior represents a high resolution (4 to 6 per year), and long (over 150 years) record of environmental change. We present results from an experiment where we tracked the oxygen isotopic values in the source waters, stem tissue waters and spine tissue for three treatments over the course of three months. These data are then compared to a previously developed mechanistic model of isotopic variation that reflects the physiological responses of Saguaro to climate variation over seasonal to century long time-scales. We also present the rationale for a new method to determine the growth rate of columnar cacti using the radiocarbon bomb spike. Our measurements reveal that oxygen and hydrogen isotopic variation among the sequentially produced and persistent spines covering the saguaro body record fluctuations in saguaro water balance. The model successfully predicts isotopic variation in spines and constrains controlling variables, yielding a powerful and high-resolution stable isotope index of water stress in the low desert. The development and refinement of an isotopic model for saguaro will serve as the basis for models applied to other species of columnar cacti in North and South America. The role of the

  6. Columnar deformation of human red blood cell by highly localized fiber optic Bessel beam stretcher.

    PubMed

    Lee, Sungrae; Joo, Boram; Jeon, Pyo Jin; Im, Seongil; Oh, Kyunghwan

    2015-11-01

    A single human red blood cell was optically stretched along two counter-propagating fiber-optic Bessel-like beams in an integrated lab-on-a-chip structure. The beam enabled highly localized stretching of RBC, and it induced a nonlinear mechanical deformation to finally reach an irreversible columnar shape that has not been reported. We characterized and systematically quantified this optically induced mechanical deformation by the geometrical aspect ratio of stretched RBC and the irreversible stretching time. The proposed RBC mechanism can realize a versatile and compact opto-mechanical platform for optical diagnosis of biological substances in the single cell level.

  7. Columnar content measurements of the solar-wind turbulence near the sun

    NASA Technical Reports Server (NTRS)

    Callahan, P. S.

    1975-01-01

    Turbulence in the solar wind near the sun is investigated using records of changes in the integrated electron columnar content along the line of sight to Mariners 6, 7, and 9. The comoving turbulence spectrum is found to be well represented by a power law with an index of about 3.9. The turbulence is shown to decline with heliocentric distance, and the data suggest a region of enhanced turbulence near the sun. The Mariner-9 spectral amplitudes are found to correspond with Zurich sunspot numbers. Implications of the present observations are discussed for contemporary theories on solar-wind heating.

  8. Fine genetic mapping of the Co locus controlling columnar growth habit in apple.

    PubMed

    Bai, Tuanhui; Zhu, Yuandi; Fernández-Fernández, Felicidad; Keulemans, Johan; Brown, Susan; Xu, Kenong

    2012-05-01

    Tree architecture is an important, complex and dynamic trait affected by diverse genetic, ontogenetic and environmental factors. 'Wijcik McIntosh', a columnar (reduced branching) sport of 'McIntosh' and a valuable genetic resource, has been used intensively in apple-breeding programs for genetic improvement of tree architecture. The columnar growth habit is primarily controlled by the dominant allele of gene Co (columnar) on linkage group-10. But the Co locus is not well mapped and the Co gene remains unknown. To precisely map the Co locus and to identify candidate genes of Co, a sequence-based approach using both peach and apple genomes was used to develop new markers linked more tightly to Co. Five new simple sequence repeats markers were developed (C1753-3520, C18470-25831, C6536-31519, C7223-38004 and C7629-22009). The first four markers were obtained from apple genomic sequences on chromosome-10, whereas the last (C7629-22009) was from an unanchored apple contig that contains an apple expressed sequence tag CV082943, which was identified through synteny analysis between the peach and apple genomes. Genetic mapping of these five markers in four F(1) populations of 528 genotypes and 290 diverse columnar selections/cultivars (818 genotypes in total) delimited the Co locus in a genetic interval with 0.37 % recombination between markers C1753-3520 and C7629-22009. Marker C18470-25831 co-segregates with Co in the 818 genotypes studied. The Co region is estimated to be 193 kb and contains 26 predicted gene in the 'Golden Delicious' genome. Among the 26 genes, three are putative LATERAL ORGAN BOUNDARIES (LOB) DOMAIN (LBD) containing transcription factor genes known of essential roles in plant lateral organ development, and are therefore considered as strong candidates of Co, designated MdLBD1, MdLBD2, and MdLBD3. Although more comprehensive studies are required to confirm the function of MdLBD1-3, the present work represents an important step forward to better

  9. The antigenotoxic activities of cactus (Opuntia ficus-indica) cladodes against the mycotoxin zearalenone in Balb/c mice: prevention of micronuclei, chromosome aberrations and DNA fragmentation.

    PubMed

    Zorgui, Lazhar; Ayed-Boussema, Imen; Ayed, Yosra; Bacha, Hassen; Hassen, Wafa

    2009-03-01

    Zearalenone (ZEN) is a potent estrogenic metabolite. Evidence of its cytotoxicity and genotoxicity has recently emerged from several reports. This study was conducted to evaluate the ability of cactus (Opuntia ficus-indica) cladodes to protect Balb/c mice against ZEN induced genotoxicity. To this end, the effect of a single dose of ZEN (40 mg/kg b.w.) alone and with extract of cactus cladodes (25, 50 and 100 mg/kg b.w.) was monitored by measuring: (i) micronuclei induction in bone marrow cells, (ii) chromosome aberrations mainly breaks and gaps in bone marrow cells also and finally and (iii) DNA fragmentation in liver and kidney. Our results clearly show that ZEN is genotoxic to Balb/c mice. It induces DNA damage as indicated by DNA fragmentation, micronuclei and chromosomal aberrations in bone marrow cells. It is of note that cactus cladodes extract assayed alone at high dose (100 mg/kg b.w.) was found completely safe and did not induce any genotoxic effects. The simultaneous administration of cactus cladodes extract with ZEN resulted in an efficient prevention of micronuclei (the number of PCE MN decreased from 71.3+/-6.1 for animals treated with Zen to 32.6+/-15.5 for animals treated with cactus cladodes), chromosomal aberrations frequency (the % of chromosomal aberrations decreased from 38.3+/-3.0 to 18.6+/-1.1) in bone marrow cells and of DNA fragmentation compared to the group treated with ZEN alone. It could be concluded that cactus cladodes extract was effective in the protection against ZEN genotoxicity. This could be relevant, particularly with the emergent demand for natural products which may neutralize the genotoxic effects of the multiple food contaminants.

  10. The antigenotoxic activities of cactus (Opuntia ficus-indica) cladodes against the mycotoxin zearalenone in Balb/c mice: prevention of micronuclei, chromosome aberrations and DNA fragmentation.

    PubMed

    Zorgui, Lazhar; Ayed-Boussema, Imen; Ayed, Yosra; Bacha, Hassen; Hassen, Wafa

    2009-03-01

    Zearalenone (ZEN) is a potent estrogenic metabolite. Evidence of its cytotoxicity and genotoxicity has recently emerged from several reports. This study was conducted to evaluate the ability of cactus (Opuntia ficus-indica) cladodes to protect Balb/c mice against ZEN induced genotoxicity. To this end, the effect of a single dose of ZEN (40 mg/kg b.w.) alone and with extract of cactus cladodes (25, 50 and 100 mg/kg b.w.) was monitored by measuring: (i) micronuclei induction in bone marrow cells, (ii) chromosome aberrations mainly breaks and gaps in bone marrow cells also and finally and (iii) DNA fragmentation in liver and kidney. Our results clearly show that ZEN is genotoxic to Balb/c mice. It induces DNA damage as indicated by DNA fragmentation, micronuclei and chromosomal aberrations in bone marrow cells. It is of note that cactus cladodes extract assayed alone at high dose (100 mg/kg b.w.) was found completely safe and did not induce any genotoxic effects. The simultaneous administration of cactus cladodes extract with ZEN resulted in an efficient prevention of micronuclei (the number of PCE MN decreased from 71.3+/-6.1 for animals treated with Zen to 32.6+/-15.5 for animals treated with cactus cladodes), chromosomal aberrations frequency (the % of chromosomal aberrations decreased from 38.3+/-3.0 to 18.6+/-1.1) in bone marrow cells and of DNA fragmentation compared to the group treated with ZEN alone. It could be concluded that cactus cladodes extract was effective in the protection against ZEN genotoxicity. This could be relevant, particularly with the emergent demand for natural products which may neutralize the genotoxic effects of the multiple food contaminants. PMID:19152824

  11. Evidence for regulation of columnar habit in apple by a putative 2OG-Fe(II) oxygenase.

    PubMed

    Wolters, Pieter J; Schouten, Henk J; Velasco, Riccardo; Si-Ammour, Azeddine; Baldi, Paolo

    2013-12-01

    Understanding the genetic mechanisms controlling columnar-type growth in the apple mutant 'Wijcik' will provide insights on how tree architecture and growth are regulated in fruit trees. In apple, columnar-type growth is controlled by a single major gene at the Columnar (Co) locus. By comparing the genomic sequence of the Co region of 'Wijcik' with its wild-type 'McIntosh', a novel non-coding DNA element of 1956 bp specific to Pyreae was found to be inserted in an intergenic region of 'Wijcik'. Expression analysis of selected genes located in the vicinity of the insertion revealed the upregulation of the MdCo31 gene encoding a putative 2OG-Fe(II) oxygenase in axillary buds of 'Wijcik'. Constitutive expression of MdCo31 in Arabidopsis thaliana resulted in compact plants with shortened floral internodes, a phenotype reminiscent of the one observed in columnar apple trees. We conclude that MdCo31 is a strong candidate gene for the control of columnar growth in 'Wijcik'.

  12. Application of the Prague C and M criteria for endoscopic description of columnar-lined esophagus in South Korea

    PubMed Central

    Choe, Jung Wan; Kim, Young Choon; Joo, Moon Kyung; Kim, Hyo Jung; Lee, Beom Jae; Kim, Ji Hoon; Yeon, Jong Eun; Park, Jong-Jae; Kim, Jae Seon; Byun, Kwan Soo; Bak, Young-Tae

    2016-01-01

    AIM: To ascertain whether the Prague circumferential (C) length and maximal (M) length criteria for grading the extent of Barrett’s esophagus can be applied prior to its widespread application in South Korea. METHODS: Two hundred and thirteen consecutive cases with endoscopic columnar-lined esophagus (CLE) were included and classified according to the Prague C and M criteria. RESULTS: Of 213 cases with CLE, the distribution of maximum CLE lengths was: 0.5-0.9 cm in 99 cases (46.5%); 1.0-1.4 cm in 63 cases (29.6%); 1.5-1.9 cm in 15 cases (7.0%); 2.0-2.4 cm in 14 cases (6.6%); 2.5-2.9 cm in 1 case (0.5%); and 7.0 cm in 1 case (0.5%). Twenty cases (9.4%) had columnar islands alone. Two hundred and eight cases (97.7%) lacked the circumferential CLE component (C0Mx). Columnar islands were found in 70 cases (32.9%), of which 20 cases (9.4%) had columnar islands alone. CONCLUSION: In regions where most CLE patients display short or ultrashort tongue-like appearance, more detailed descriptions of CLE’s in < 1.0 cm lengths and columnar islands, as well as avoidance of repeating the prefix “C0” need to be considered in parallel with the widespread application of the Prague system in South Korea. PMID:27114749

  13. Preparation of High Silicon Electrical Steel Sheets with Strong {100} Recrystallization Texture by the Texture Inheritance of Initial Columnar Grains

    NASA Astrophysics Data System (ADS)

    Pan, Hongjiang; Zhang, Zhihao; Xie, Jianxin

    2016-05-01

    Texture evolutions and recrystallization texture features in warm- and cold-rolled sheets of high silicon electrical steel with two different initial microstructures (columnar-grained and equiaxed-grained microstructures) were investigated. The relationships between the recrystallization textures and the initial textures (the textures before rolling) of the samples were analyzed. The results showed that after annealing at 1073 K (800 °C) for 1 hour, strong {100} recrystallization textures with volume fractions of more than 47 pct were obtained in the columnar-grained samples fabricated by warm and cold rolling along the growing direction of the columnar grains. While after rolling and annealing in the same processes, only 12.8 pct volume fractions of {100} recrystallization texture were revealed in the equiaxed-grained samples. The formation of strong {100} recrystallization texture in the annealed sheets of high silicon electrical steel with initial columnar grains was attributed to the favorable texture inheritance of the initial texture during rolling and annealing. The columnar grains of strong near {100}<001> ({100}<001> {310}<001>) orientation in the samples before rolling were transferred into deformed grains with orientations such as {100}<011> and {100}<012>. after rolling. Afterwards, these deformed grains were further transferred into {100} oriented recrystallized grains, which formed strong {100} recrystallization texture in the annealed sheets and exhibited preferable soft magnetic properties.

  14. Effect of Column Disorder on Carrier Transport in Columnar Discotic Liquid Crystal Evaluated by Applying Precisely Controlled Shear Stress

    NASA Astrophysics Data System (ADS)

    Kim, Jaeki; Yamasaki, Naoyuki; Hayashi, Takeshi; Katayama, Mitsuyoshi; Yoshida, Hiroyuki; Moritake, Hiroshi; Fujii, Akihiko; Ozaki, Masanori

    2013-10-01

    The effect of column disorder on carrier drift mobility in columnar discotic liquid crystals has been investigated by applying a precisely controlled oscillating shear stress. Drift mobilities on the order of 10-1 cm2.V-1.s-1 were confirmed for positive and negative carriers in the columnar phase of 1,4,8,11,15,18,22,25-octahexylphthalocyanine in a well-aligned homeotropic geometry, in which the columnar axis was perfectly perpendicular to substrates with an electrode. A slight tilt of the columnar axis upon applying shear stress led to a marked decrease in electronic carrier mobility from 10-1 to less than 10-6 cm2.V-1.s-1, and transport was only confirmed for positive ion carriers. This result indicates that a uniform shear stress blocks the carrier transport path in the entire area of the electrode, and one-dimensional carrier transport path along the columns is easily hindered in columnar discotic liquid crystals.

  15. Computer-aided vaccine designing approach against fish pathogens Edwardsiella tarda and Flavobacterium columnare using bioinformatics softwares

    PubMed Central

    Mahendran, Radha; Jeyabaskar, Suganya; Sitharaman, Gayathri; Michael, Rajamani Dinakaran; Paul, Agnal Vincent

    2016-01-01

    Edwardsiella tarda and Flavobacterium columnare are two important intracellular pathogenic bacteria that cause the infectious diseases edwardsiellosis and columnaris in wild and cultured fish. Prediction of major histocompatibility complex (MHC) binding is an important issue in T-cell epitope prediction. In a healthy immune system, the T-cells must recognize epitopes and induce the immune response. In this study, T-cell epitopes were predicted by using in silico immunoinformatics approach with the help of bioinformatics tools that are less expensive and are not time consuming. Such identification of binding interaction between peptides and MHC alleles aids in the discovery of new peptide vaccines. We have reported the potential peptides chosen from the outer membrane proteins (OMPs) of E. tarda and F. columnare, which interact well with MHC class I alleles. OMPs from E. tarda and F. columnare were selected and analyzed based on their antigenic and immunogenic properties. The OMPs of the genes TolC and FCOL_04620, respectively, from E. tarda and F. columnare were taken for study. Finally, two epitopes from the OMP of E. tarda exhibited excellent protein–peptide interaction when docked with MHC class I alleles. Five epitopes from the OMP of F. columnare had good protein–peptide interaction when docked with MHC class I alleles. Further in vitro studies can aid in the development of potential peptide vaccines using the predicted peptides. PMID:27284239

  16. Computer-aided vaccine designing approach against fish pathogens Edwardsiella tarda and Flavobacterium columnare using bioinformatics softwares.

    PubMed

    Mahendran, Radha; Jeyabaskar, Suganya; Sitharaman, Gayathri; Michael, Rajamani Dinakaran; Paul, Agnal Vincent

    2016-01-01

    Edwardsiella tarda and Flavobacterium columnare are two important intracellular pathogenic bacteria that cause the infectious diseases edwardsiellosis and columnaris in wild and cultured fish. Prediction of major histocompatibility complex (MHC) binding is an important issue in T-cell epitope prediction. In a healthy immune system, the T-cells must recognize epitopes and induce the immune response. In this study, T-cell epitopes were predicted by using in silico immunoinformatics approach with the help of bioinformatics tools that are less expensive and are not time consuming. Such identification of binding interaction between peptides and MHC alleles aids in the discovery of new peptide vaccines. We have reported the potential peptides chosen from the outer membrane proteins (OMPs) of E. tarda and F. columnare, which interact well with MHC class I alleles. OMPs from E. tarda and F. columnare were selected and analyzed based on their antigenic and immunogenic properties. The OMPs of the genes TolC and FCOL_04620, respectively, from E. tarda and F. columnare were taken for study. Finally, two epitopes from the OMP of E. tarda exhibited excellent protein-peptide interaction when docked with MHC class I alleles. Five epitopes from the OMP of F. columnare had good protein-peptide interaction when docked with MHC class I alleles. Further in vitro studies can aid in the development of potential peptide vaccines using the predicted peptides. PMID:27284239

  17. Modelling of macrosegregation in direct chill casting considering columnar-to-equiaxed transition using 3-phase Eulerian approach

    NASA Astrophysics Data System (ADS)

    Hao, J.; Lin, Y. J.; Nie, Y.; Wu, M.; Ludwig, A.

    2015-06-01

    A 3-phase Eulerian approach is used to model the macrosegregation during solidification in direct chill (DC) casting of binary bronze (Cu-Sn). The three phases are the melt, the solidifying columnar dendrites and the equiaxed grains. The thermodynamic information of Cu-Sn is included based on published thermodynamic data, which are coupled with the 3-phase solidification model. The occurrence of columnar-to-equiaxed transition (CET), phase interactions, feeding flow, equiaxed sedimentation and their influence on macrosegregation are considered in the model. The model is applied to a laboratory DC casting process of bronze as a benchmark to demonstrate the model potentials. The simulation results of mixed columnar and equiaxed solidification as well as the formation of macrosegregation are presented. The focus of this work is to analyze and discuss the macrosegregation mechanisms by different flow including feeding flow and crystal sedimentation.

  18. Benchmark experiments and numerical modelling of the columnar-equiaxed dendritic growth in the transparent alloy Neopentylglycol-(d)Camphor

    NASA Astrophysics Data System (ADS)

    Sturz, L.; Wu, M.; Zimmermann, G.; Ludwig, A.; Ahmadein, M.

    2015-06-01

    Solidification benchmark experiments on columnar and equiaxed dendritic growth, as well as the columnar-equiaxed transition have been carried out under diffusion-dominated conditions for heat and mass transfer in a low-gravity environment. The system under investigation is the transparent organic alloy system Neopentylglycol-37.5wt.-%(d)Camphor, processed aboard a TEXUS sounding rocket flight. Solidifications was observed by standard optical methods in addition to measurements of the thermal fields within the sheet like experimental cells of 1 mm thickness. The dendrite tip kinetic, primary dendrite arm spacing, temporal and spatial temperature evolution, columnar tip velocity and the critical parameters at the CET have been analysed. Here we focus on a detailed comparison of the experiment “TRACE” with a 5-phase volume averaging model to validate the numerical model and to give insight into the corresponding physical mechanisms and parameters leading to CET. The results are discussed in terms of sensitivity versus numerical parameters.

  19. Mixed columnar cell and tall cell variant of papillary carcinoma of thyroid: a case report and review of the literature.

    PubMed

    Putti, T C; Bhuiya, T A

    2000-11-01

    Columnar cell and tall cell carcinomas are newly described variants of papillary thyroid carcinoma associated with aggressive clinical behaviour. Although several cases of tall cell and columnar cell variants have been reported, only a single detailed case report of a mixed tall cell and columnar cell variant has been described in the English-language literature. We report another such composite tumour with predominant columna cell features in an elderly female. The tumour showed extrathyroidal extension with intraluminal superior thyroid vein invasion and lymph node metastasis. DNA ploidy analysis showed a diploid DNA content with no increase of S-phase fraction. Immunohistochemistry showed focal positivity for p53 and Ki-67 at the infiltrating margins of the tumour and diffuse positivity for proliferating cell nuclear antigen. The adverse clinical course warrants aggressive treatment and careful follow-up.

  20. Effect of counterion on the mesomorphic behavior and optical properties of columnar pyridinium ionic liquid crystals derived from 4-hydroxypyridine

    NASA Astrophysics Data System (ADS)

    Pană, Amalia; Badea, Florentina L.; Iliş, Monica; Staicu, Teodora; Micutz, Marin; Pasuk, Iuliana; Cîrcu, Viorel

    2015-03-01

    A series of 3,4,5-tridodecyloxybenzyl pyridinium salts derived from 4-hydroxypyridine has been designed and prepared. The liquid crystalline properties of these compounds were investigated by polarized optical microscopy, differential scanning calorimetry and powder X-ray diffraction while their thermal stability was studied by thermogravimetric analysis. The N-3,4,5-tridodecyloxybenzyl-4-pyridone intermediate shows a monotropic columnar hexagonal mesophase ranging from 56 °C down to room temperature while the corresponding bromide dodecyl O-alkylated pyridinium salt shows one enantiotropic columnar mesophase and one additional monotropic columnar phase at lower temperatures. Replacing bromide ion (Br-) with other counterions (NO3-, BF4- and PF6-) resulted in mesophase suppression. These luminescent pyridinium salts show weak emission in dichloromethane solutions at room temperature and a pronounced red-shifted emission in solid state. Photoluminescent properties of the pyridinium salts do not depend significantly on the nature of counterion employed.

  1. Thermal Evaporation versus Spin-Coating: Electrical Performance in Columnar Liquid Crystal OLEDs.

    PubMed

    Eccher, Juliana; Zajaczkowski, Wojciech; Faria, Gregório C; Bock, Harald; von Seggern, Heinz; Pisula, Wojciech; Bechtold, Ivan H

    2015-08-01

    The electrical responses of a columnar liquid crystal (a diimidodiester derivative of benzo[ghi]perylene) deposited either by spin-coating or by thermal evaporation into a typical OLED device are compared. For the spin-coated film, homeotropic alignment was induced by thermal annealing, which enhanced the charge carrier mobility significantly. For the evaporated films, homeotropic alignment could not be obtained by annealing. However, a degree of rectification higher than 3 orders of magnitude was achieved, even without annealing, with an electrical response similar to the response of the aligned spin-coated film. A trap-limited space-charge-limited current model was used to extract the charge carrier mobility directly from the current-voltage curves. Grazing incidence wide-angle X-ray scattering confirmed the homeotropic alignment of the annealed spin-coated film, whereas the columns are mostly oriented parallel to the surface in the evaporated case. In a field-effect transistor with bottom-gate bottom-contact geometry, the evaporated film exhibited a typical behavior of an n-type transistor. The degree of intermolecular order is thereby strongly dependent on the deposition method where vacuum deposition leads to a higher order. This higher order, however, impedes reorientation by annealing of the evaporated film but leads to improved charge transport between the electrodes even without homeotropic alignment of columnar liquid crystal.

  2. The Influence of Ionic Environment and Histone Tails on Columnar Order of Nucleosome Core Particles.

    PubMed

    Berezhnoy, Nikolay V; Liu, Ying; Allahverdi, Abdollah; Yang, Renliang; Su, Chun-Jen; Liu, Chuan-Fa; Korolev, Nikolay; Nordenskiöld, Lars

    2016-04-26

    The nucleosome core particle (NCP) is the basic building block of chromatin. Nucleosome-nucleosome interactions are instrumental in chromatin compaction, and understanding NCP self-assembly is important for understanding chromatin structure and dynamics. Recombinant NCPs aggregated by multivalent cations form various ordered phases that can be studied by x-ray diffraction (small-angle x-ray scattering). In this work, the effects on the supramolecular structure of aggregated NCPs due to lysine histone H4 tail acetylations, histone H2A mutations (neutralizing the acidic patch of the histone octamer), and the removal of histone tails were investigated. The formation of ordered mainly hexagonal columnar NCP phases is in agreement with earlier studies; however, the highly homogeneous recombinant NCP systems used in this work display a more compact packing. The long-range order of the NCP columnar phase was found to be abolished or reduced by acetylation of the H4 tails, acidic patch neutralization, and removal of the H3 and H2B tails. Loss of nucleosome stacking upon removal of the H3 tails in combination with other tails was observed. In the absence of the H2A tails, the formation of an unknown highly ordered phase was observed. PMID:27119633

  3. Stability of columnar order in assemblies of hard rectangles or squares

    NASA Astrophysics Data System (ADS)

    Nath, Trisha; Dhar, Deepak; Rajesh, R.

    2016-04-01

    A system of 2 × d hard rectangles on a square lattice is known to show four different phases for d ≥ 14. As the covered area fraction ρ is increased from 0 to 1, the system goes from a low-density disordered phase to an orientationally ordered nematic phase, to a columnar phase with orientational order and also broken translational invariance, to a high-density phase in which orientational order is lost. For large d, the threshold density for the first transition ρ_1* tends to 0, and the critical density for the third transition ρ_3* tends to 1. Interestingly, simulations have shown that the critical density for the second transition ρ_2* tends to a non-trivial finite value ≈ 0.73 , as d → ∞ , and ρ_2* ≈ 0.93 for d = 2. We provide a theoretical explanation of this interesting result. We develop an approximation scheme to calculate the surface tension between two differently ordered columnar phases. The density at which the surface tension vanishes gives an estimate ρ_2* = 0.746 , for d\\to ∞ , and ρ_2^*=0.923 for d = 2. For all values of d, these estimates are in good agreement with Monte Carlo data.

  4. Columnar structured FePt films epitaxially grown on large lattice mismatched intermediate layer

    PubMed Central

    Dong, K. F.; Deng, J. Y.; Peng, Y. G.; Ju, G.; Chow, G. M.; Chen, J. S.

    2016-01-01

    The microstructure and magnetic properties of the FePt films grown on large mismatched ZrN (15.7%) intermediate layer were investigated. With using ZrN intermediate layer, FePt 10 nm films exhibited (001) texture except for some weaker FePt (110) texture. Good epitaxial relationships of FePt (001) <100>//ZrN (001) <100>//TiN (001) <100> among FePt and ZrN/TiN were revealed from the transmission electron microscopy (TEM) results. As compared with TiN intermediate layer, although FePt-SiO2-C films grown on ZrN/TiN intermediate layer showed isotropic magnetic properties, the large interfacial energy and lattice mismatch between FePt and ZrN would lead to form columnar structural FePt films with smaller grain size and improved isolation. By doping ZrN into the TiN layer, solid solution of ZrTiN was formed and the lattice constant is increased comparing with TiN and decreased comparing with ZrN. Moreover, FePt-SiO2-C films grown on TiN 2 nm-20 vol.% ZrN/TiN 3 nm intermediate layer showed an improved perpendicular magnetic anisotropy. Simultaneously, columnar structure with smaller grain size retained. PMID:27686046

  5. Columnar-Structured Mg-Al-Spinel Thermal Barrier Coatings (TBCs) by Suspension Plasma Spraying (SPS)

    NASA Astrophysics Data System (ADS)

    Schlegel, N.; Ebert, S.; Mauer, G.; Vaßen, R.

    2015-01-01

    The suspension plasma spraying (SPS) process has been developed to permit the feeding of sub-micrometer-sized powder into the plasma plume. In contrast to electron beam-physical vapor deposition and plasma spray-physical vapor deposition, SPS enables the cost-efficient deposition of columnar-structured coatings. Due to their strain tolerance, these coatings play an important role in the field of thermal barrier coatings (TBCs). In addition to the cost-efficient process, attention was turned to the TBC material. Nowadays, yttria partially stabilized zirconia (YSZ) is used as standard TBC material. However, its long-term application at temperatures higher than 1200 °C is problematic. At these high temperatures, phase transitions and sintering effects lead to the degradation of the TBC system. To overcome those deficits of YSZ, Mg-Al-spinel was chosen as TBC material. Even though it has a lower melting point (~2135 °C) and a higher thermal conductivity (~2.5 W/m/K) than YSZ, Mg-Al-spinel provides phase stability at high temperatures in contrast to YSZ. The Mg-Al-spinel deposition by SPS resulted in columnar-structured coatings, which have been tested for their thermal cycling lifetime. Furthermore, the influence of substrate cooling during the spraying process on thermal cycling behavior, phase composition, and stoichiometry of the Mg-Al-spinel has been investigated.

  6. Charge transport in columnar arrays of self-organizing molecular dendrons

    NASA Astrophysics Data System (ADS)

    Singer, Kenneth; Shiyanovskaya, Irina; Percec, Virgil; Glodde, Martin

    2003-03-01

    We report a universal design strategy in which functional fluorinated tapered dendrons are programmed to self-assemble into supramolecular nanocylinders containing pi-electron stacks of high carrier mobility donors (D), acceptors (A) or D-A complexes in the core. The resulting helical columnar structure suggests that supramolecular order and electronic function can be independently manipulated for facile functional design. The cylinders form columnar liquid crystal phases that can be aligned into large domain structures both parallel and perpendicular to a conducting substrate. We report on measurements of time-of-flight charge carrier mobility, and discuss the temperature and electric field-independent high hole mobility of 1-3.5 X 10-3cm^2/Vs of fluorinated tapered first generation dendrons that contain pyrene and naphthalene groups in their core. The anomalous temperature behavior of the mobility is consistent with polaron transport mechanisms. Studies of time-of-flight transients, which reveal evidence for dynamic defects with lifetimes in the range of 10-6 s, are presented as aspects of charge generation and recombination kinetics. We also describe how these materials can be formed into mechanically robust phases such as fine polymer fibers and ribbons, as well as room-temperature glasses.

  7. The tumor suppressor PTEN and the PDK1 kinase regulate formation of the columnar neural epithelium

    PubMed Central

    Grego-Bessa, Joaquim; Bloomekatz, Joshua; Castel, Pau; Omelchenko, Tatiana; Baselga, José; Anderson, Kathryn V

    2016-01-01

    Epithelial morphogenesis and stability are essential for normal development and organ homeostasis. The mouse neural plate is a cuboidal epithelium that remodels into a columnar pseudostratified epithelium over the course of 24 hr. Here we show that the transition to a columnar epithelium fails in mutant embryos that lack the tumor suppressor PTEN, although proliferation, patterning and apical-basal polarity markers are normal in the mutants. The Pten phenotype is mimicked by constitutive activation of PI3 kinase and is rescued by the removal of PDK1 (PDPK1), but does not depend on the downstream kinases AKT and mTORC1. High resolution imaging shows that PTEN is required for stabilization of planar cell packing in the neural plate and for the formation of stable apical-basal microtubule arrays. The data suggest that appropriate levels of membrane-associated PDPK1 are required for stabilization of apical junctions, which promotes cell elongation, during epithelial morphogenesis. DOI: http://dx.doi.org/10.7554/eLife.12034.001 PMID:26809587

  8. The morphological evolution of the axial structure and the curved columnar grain in the weld

    NASA Astrophysics Data System (ADS)

    Han, Rihong; Lu, Shanping; Dong, Wenchao; Li, Dianzhong; Li, Yiyi

    2015-12-01

    The competitive growth of microstructures in the entire weld pool for both the Al-Cu alloy and the pure aluminum was simulated by the cellular automata method to comparatively investigate the micro-mechanisms for the morphological evolution of the axial structure and the curved columnar grain in the weld. The competitive mechanism of grains during the epitaxial growth and the morphological evolution of the grain structure in the weld with various welding speeds were studied. The results indicate that both the thermal conditions and the solidification characteristic of the weld metal exert an important influence on the grain competition and the resulting structure in the weld. For the Al-Cu alloy, the dendritic structure with a large S/L interface curvature appears during the epitaxial growth. The preferential orientation affects the competition result obviously. Owing to the anisotropic growth kinetics, the straight axial structure forms at low welding speeds. With the increase of the welding speed, the width of the axial region decreases and eventually disappears. For the pure aluminum, the S/L interface during the epitaxial growth is planar, and the grain competition is controlled by the thermal conditions completely. The columnar grains curve gradually to follow the highest temperature gradient direction at low welding speeds and become straight at high welding speeds.

  9. A Columnar Storage Strategy with Spatiotemporal Index for Big Climate Data

    NASA Astrophysics Data System (ADS)

    Hu, F.; Bowen, M. K.; Li, Z.; Schnase, J. L.; Duffy, D.; Lee, T. J.; Yang, C. P.

    2015-12-01

    Large collections of observational, reanalysis, and climate model output data may grow to as large as a 100 PB in the coming years, so climate dataset is in the Big Data domain, and various distributed computing frameworks have been utilized to address the challenges by big climate data analysis. However, due to the binary data format (NetCDF, HDF) with high spatial and temporal dimensions, the computing frameworks in Apache Hadoop ecosystem are not originally suited for big climate data. In order to make the computing frameworks in Hadoop ecosystem directly support big climate data, we propose a columnar storage format with spatiotemporal index to store climate data, which will support any project in the Apache Hadoop ecosystem (e.g. MapReduce, Spark, Hive, Impala). With this approach, the climate data will be transferred into binary Parquet data format, a columnar storage format, and spatial and temporal index will be built and attached into the end of Parquet files to enable real-time data query. Then such climate data in Parquet data format could be available to any computing frameworks in Hadoop ecosystem. The proposed approach is evaluated using the NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA) climate reanalysis dataset. Experimental results show that this approach could efficiently overcome the gap between the big climate data and the distributed computing frameworks, and the spatiotemporal index could significantly accelerate data querying and processing.

  10. Elasticity, fluctuations, and vortex pinning in ferromagnetic superconductors: A columnar elastic glass

    NASA Astrophysics Data System (ADS)

    Ettouhami, A. M.; Saunders, Karl; Radzihovsky, L.; Toner, John

    2005-06-01

    We study the elasticity, fluctuations, and pinning of a putative spontaneous vortex solid in ferromagnetic superconductors. Using a rigorous thermodynamic argument, we show that in the idealized case of vanishing crystalline pinning anisotropy the long-wavelength tilt modulus of such a vortex solid vanishes identically, as guaranteed by the underlying rotational invariance. The vanishing of the tilt modulus means that, to lowest order, the associated tension elasticity is replaced by the softer, curvature elasticity. The effect of this is to make the spontaneous vortex solid qualitatively more susceptible to the disordering effects of thermal fluctuations and random pinning. We study these effects, taking into account the nonlinear elasticity, that, in three dimensions, is important at sufficiently long length scales, and showing that a “columnar elastic glass” phase of vortices results. This phase is controlled by a previously unstudied zero-temperature fixed point, and it is characterized by elastic moduli that have universal strong wave-vector dependence out to arbitrarily long length scales, leading to non-Hookean elasticity. We argue that, although translationally disordered for weak disorder, the columnar elastic glass is stable against the proliferation of dislocations and is, therefore, a topologically ordered elastic glass. As a result, the phenomenology of the spontaneous vortex state of isotropic magnetic superconductors differs qualitatively from a conventional, external-field-induced mixed state. For example, for weak external fields H , the magnetic induction scales universally like B(H)˜B(0)+cHα , with α≈0.72 .

  11. Thermal Evaporation versus Spin-Coating: Electrical Performance in Columnar Liquid Crystal OLEDs.

    PubMed

    Eccher, Juliana; Zajaczkowski, Wojciech; Faria, Gregório C; Bock, Harald; von Seggern, Heinz; Pisula, Wojciech; Bechtold, Ivan H

    2015-08-01

    The electrical responses of a columnar liquid crystal (a diimidodiester derivative of benzo[ghi]perylene) deposited either by spin-coating or by thermal evaporation into a typical OLED device are compared. For the spin-coated film, homeotropic alignment was induced by thermal annealing, which enhanced the charge carrier mobility significantly. For the evaporated films, homeotropic alignment could not be obtained by annealing. However, a degree of rectification higher than 3 orders of magnitude was achieved, even without annealing, with an electrical response similar to the response of the aligned spin-coated film. A trap-limited space-charge-limited current model was used to extract the charge carrier mobility directly from the current-voltage curves. Grazing incidence wide-angle X-ray scattering confirmed the homeotropic alignment of the annealed spin-coated film, whereas the columns are mostly oriented parallel to the surface in the evaporated case. In a field-effect transistor with bottom-gate bottom-contact geometry, the evaporated film exhibited a typical behavior of an n-type transistor. The degree of intermolecular order is thereby strongly dependent on the deposition method where vacuum deposition leads to a higher order. This higher order, however, impedes reorientation by annealing of the evaporated film but leads to improved charge transport between the electrodes even without homeotropic alignment of columnar liquid crystal. PMID:26168313

  12. Does Cell Lineage in the Developing Cerebral Cortex Contribute to its Columnar Organization?

    PubMed Central

    Costa, Marcos R.; Hedin-Pereira, Cecilia

    2010-01-01

    Since the pioneer work of Lorente de Nó, Ramón y Cajal, Brodmann, Mountcastle, Hubel and Wiesel and others, the cerebral cortex has been seen as a jigsaw of anatomic and functional modules involved in the processing of different sets of information. In fact, a columnar distribution of neurons displaying similar functional properties throughout the cerebral cortex has been observed by many researchers. Although it has been suggested that much of the anatomical substrate for such organization would be already specified at early developmental stages, before activity-dependent mechanisms could take place, it is still unclear whether gene expression in the ventricular zone (VZ) could play a role in the development of discrete functional units, such as minicolumns or columns. Cell lineage experiments using replication-incompetent retroviral vectors have shown that the progeny of a single neuroepithelial/radial glial cell in the dorsal telencephalon is organized into discrete radial clusters of sibling excitatory neurons, which have a higher propensity for developing chemical synapses with each other rather than with neighboring non-siblings. Here, we will discuss the possibility that the cell lineage of single neuroepithelial/radial glia cells could contribute for the columnar organization of the neocortex by generating radial columns of sibling, interconnected neurons. Borrowing some concepts from the studies on cell–cell recognition and transcription factor networks, we will also touch upon the potential molecular mechanisms involved in the establishment of sibling-neuron circuits. PMID:20676384

  13. Self-assembly Columnar Structure in Active Layer of Bulk Heterojunction Solar Cell

    NASA Astrophysics Data System (ADS)

    Pan, Cheng; Segui, Jennifer; Yu, Yingjie; Li, Hongfei; Akgun, Bulent; Satijia, Sushil. K.; Gersappe, Dilip; Nam, Chang-Yong; Rafailovich, Miriam

    2012-02-01

    Bulk Heterojunction (BHJ) polymer solar cells are an area of intense interest due to their flexibility and relatively low cost. However, due to the disordered inner structure in active layer, the power conversion efficiency of BHJ solar cell is relatively low. Our research provides the method to produce ordered self-assembly columnar structure within active layer of bulk heterojunction (BHJ) solar cell by introducing polystyrene (PS) into the active layer. The blend thin film of polystyrene, poly (3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) at different ratio are spin coated on substrate and annealed in vacuum oven for certain time. Atomic force microscopy (AFM) images show uniform phase segregation on the surface of polymer blend thin film and highly ordered columnar structure is then proven by etching the film with ion sputtering. TEM cross-section technology is also used to investigate the column structure. Neutron reflectometry was taken to establish the confinement of PCBM at the interface of PS and P3HT. The different morphological structures formed via phase segregation will be correlated with the performance of the PEV cells to be fabricated at the BNL-CFN.

  14. Columnar Processing in Primate pFC: Evidence for Executive Control Microcircuits

    PubMed Central

    Opris, Ioan; Hampson, Robert E.; Gerhardt, Greg A.; Berger, Theodore W.; Deadwyler, Sam A.

    2013-01-01

    A common denominator for many cognitive disorders of human brain is the disruption of neural activity within pFC, whose structural basis is primarily interlaminar (columnar) microcircuits or “mini-columns.” The importance of this brain region for executive decision-making has been well documented; however, because of technological constraints, the minicolumnar basis is not well understood. Here, via implementation of a unique conformal multielectrode recording array, the role of interlaminar pFC minicolumns in the executive control of task-related target selection is demonstrated in nonhuman primates performing a visuomotor DMS task. The results reveal target-specific, interlaminar correlated firing during the decision phase of the trial between multielectrode recording array-isolated minicolumnar pairs of neurons located in parallel in layers 2/3 and layer 5 of pFC. The functional significance of individual pFC minicolumns (separated by 40 μm) was shown by reduced correlated firing between cell pairs within single minicolumns on error trials with inappropriate target selection. To further demonstrate dependence on performance, a task-disrupting drug (cocaine) was administered in the middle of the session, which also reduced interlaminar firing in minicolumns that fired appropriately in the early (nondrug) portion of the session. The results provide a direct demonstration of task-specific, real-time columnar processing in pFC indicating the role of this type of microcircuit in executive control of decision-making in primate brain. PMID:23016850

  15. Topology of ON and OFF inputs in visual cortex enables an invariant columnar architecture.

    PubMed

    Lee, Kuo-Sheng; Huang, Xiaoying; Fitzpatrick, David

    2016-05-01

    Circuits in the visual cortex integrate the information derived from separate ON (light-responsive) and OFF (dark-responsive) pathways to construct orderly columnar representations of stimulus orientation and visual space. How this transformation is achieved to meet the specific topographic constraints of each representation remains unclear. Here we report several novel features of ON-OFF convergence visualized by mapping the receptive fields of layer 2/3 neurons in the tree shrew (Tupaia belangeri) visual cortex using two-photon imaging of GCaMP6 calcium signals. We show that the spatially separate ON and OFF subfields of simple cells in layer 2/3 exhibit topologically distinct relationships with the maps of visual space and orientation preference. The centres of OFF subfields for neurons in a given region of cortex are confined to a compact region of visual space and display a smooth visuotopic progression. By contrast, the centres of the ON subfields are distributed over a wider region of visual space, display substantial visuotopic scatter, and have an orientation-specific displacement consistent with orientation preference map structure. As a result, cortical columns exhibit an invariant aggregate receptive field structure: an OFF-dominated central region flanked by ON-dominated subfields. This distinct arrangement of ON and OFF inputs enables continuity in the mapping of both orientation and visual space and the generation of a columnar map of absolute spatial phase. PMID:27120162

  16. Columnar processing in primate pFC: evidence for executive control microcircuits.

    PubMed

    Opris, Ioan; Hampson, Robert E; Gerhardt, Greg A; Berger, Theodore W; Deadwyler, Sam A

    2012-12-01

    A common denominator for many cognitive disorders of human brain is the disruption of neural activity within pFC, whose structural basis is primarily interlaminar (columnar) microcircuits or "minicolumns." The importance of this brain region for executive decision-making has been well documented; however, because of technological constraints, the minicolumnar basis is not well understood. Here, via implementation of a unique conformal multielectrode recording array, the role of interlaminar pFC minicolumns in the executive control of task-related target selection is demonstrated in nonhuman primates performing a visuomotor DMS task. The results reveal target-specific, interlaminar correlated firing during the decision phase of the trial between multielectrode recording array-isolated minicolumnar pairs of neurons located in parallel in layers 2/3 and layer 5 of pFC. The functional significance of individual pFC minicolumns (separated by 40 μm) was shown by reduced correlated firing between cell pairs within single minicolumns on error trials with inappropriate target selection. To further demonstrate dependence on performance, a task-disrupting drug (cocaine) was administered in the middle of the session, which also reduced interlaminar firing in minicolumns that fired appropriately in the early (nondrug) portion of the session. The results provide a direct demonstration of task-specific, real-time columnar processing in pFC indicating the role of this type of microcircuit in executive control of decision-making in primate brain. PMID:23016850

  17. Thermal Energy Exchange Model and Water Loss of a Barrel Cactus, Ferocactus acanthodes1

    PubMed Central

    Lewis, Donald A.; Nobel, Park S.

    1977-01-01

    The influences of various diurnal stomatal opening patterns, spines, and ribs on the stem surface temperature and water economy of a CAM succulent, the barrel cactus Ferocactus acanthodes, were examined using an energy budget model. To incorporate energy exchanges by shortwave and longwave irradiation, latent heat, conduction, and convection as well as the heat storage in the massive stem, the plant was subdivided into over 100 internal and external regions in the model. This enabled the average surface temperature to be predicted within 1 C of the measured temperature for both winter and summer days. Reducing the stem water vapor conductance from the values observed in the field to zero caused the average daily stem surface temperature to increase only 0.7 C for a winter day and 0.3 C for a summer day. Thus, latent heat loss does not substantially reduce stem temperature. Although the surface temperatures averaged 18 C warmer for the summer day than for the winter day for a plant 41 cm tall, the temperature dependence of stomatal opening caused the simulated nighttime water loss rates to be about the same for the 2 days. Spines moderated the amplitude of the diurnal temperature changes of the stem surface, since the daily variation was 17 C for the winter day and 25 C for the summer day with spines compared with 23 C and 41 C, respectively, in their simulated absence. Ribs reduced the daytime temperature rise by providing 54% more area for convective heat loss than for a smooth circumscribing surface. In a simulation where both spines and ribs were eliminated, the daytime average surface temperature rose by 5 C. PMID:16660148

  18. An unusual stacking transformation in liquid-crystalline columnar assemblies of clicked molecular propellers with tunable light emissions.

    PubMed

    Kim, Jinhee; Cho, Sung; Cho, Byoung-Ki

    2014-09-26

    The columnar liquid-crystalline (LC) and fluorescence properties of three-dimensional molecular propellers based on tetraphenylethylene is reported. X-ray scattering studies reveal an unusual transition from a rectangular (Colrec ) to a hexagonal columnar (Colhex ) phase. In contrast to second-order intercolumnar transitions based on a common tilt mechanism, the transition is first order and involves an unprecedented zigzag stacking of aromatic propellers in the Colrec phase. A sudden change in emission color from sky blue to green occurs rapidly and reversibly at this transition, which is due to the planarization of the propeller mesogen. PMID:25124063

  19. Perylo[1,12-b,c,d] Thiophene Tetraesters: A New Class of Luminescent Columnar Liquid Crystals.

    PubMed

    Gupta, Ravindra Kumar; Pradhan, Balaram; Pathak, Suraj Kumar; Gupta, Monika; Pal, Santanu Kumar; Sudhakar, Achalkumar Ammathnadu

    2015-07-28

    Perylo[1,12-b,c,d] thiophene tetraesters exhibiting wide-range hexagonal columnar phase have been synthesized. These compounds also exhibit good homeotropic alignment in the liquid-crystalline phase which is very important for the device fabrication. These compounds showed sky-blue luminescence in solution under the long-wavelength UV light. With high solubility and high quantum yield these compounds can serve as standards to measure quantum yields of unknown samples. This new class of materials is promising, considering the emissive nature and stabilization of hexagonal columnar mesophase over a wide thermal range and ease of synthesis. PMID:26077109

  20. Flavobacterium columnare isolated from red tilapia (Oreochromis sp.): emphasis on genetic characterization and virulence of rhizoid and non-rhizoid morphotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare is the causative agent of columnaris disease and severely affects various freshwater fish species worldwide. Here, we described the phenotypic and genetic characterization of F. columnare isolates isolated from farmed red tilapia in Thailand. Additionally, the virulence as w...

  1. Bacterial community structure in the rhizosphere of three cactus species from semi-arid highlands in central Mexico.

    PubMed

    Aguirre-Garrido, J Félix; Montiel-Lugo, Daniel; Hernández-Rodríguez, César; Torres-Cortes, Gloria; Millán, Vicenta; Toro, Nicolás; Martínez-Abarca, Francisco; Ramírez-Saad, Hugo C

    2012-05-01

    The nature reserve of Tehuacan-Cuicatlan in central Mexico is known for its diversity and endemism mainly in cactus plants. Although the xerophytic flora is reasonably documented, the bacterial communities associated with these species have been largely neglected. We assessed the diversity and composition of bacterial communities in bulk (non-rhizospheric) soil and the rhizosphere of three cactus plant species: Mammillaria carnea, Opuntia pilifera and Stenocereus stellatus, approached using cultivation and molecular techniques, considering the possible effect of dry and rainy seasons. Cultivation-dependent methods were focused on putative N(2)-fixers and heterotrophic aerobic bacteria, in the two media tested the values obtained for dry season samples grouped together regardless of the sample type (rhizospheric or non-rhizospheric), these groups also included the non-rhizospheric sample for rainy season, on each medium. These CFU values were smaller and significantly different from those obtained on rhizospheric samples from rainy season. Genera composition among isolates of the rhizospheric samples was very similar for each season, the most abundant taxa being α-Proteobacteria, Actinobacteria and Firmicutes. Interestingly, the genus Ochrobactrum was highly represented among rhizospheric samples, when cultured in N-free medium. The structure of the bacterial communities was approached with molecular techniques targeting partial 16S rRNA sequences such as denaturing gradient gel electrophoresis and serial analysis of ribosomal sequence tags. Under these approaches, the most represented bacterial phyla were Actinobacteria, Proteobacteria and Acidobacteria. The first two were also highly represented when using isolation techniques.

  2. The Presence of Nuclear Cactus in the Early Drosophila Embryo May Extend the Dynamic Range of the Dorsal Gradient

    PubMed Central

    O’Connell, Michael D.; Reeves, Gregory T.

    2015-01-01

    In a developing embryo, the spatial distribution of a signaling molecule, or a morphogen gradient, has been hypothesized to carry positional information to pattern tissues. Recent measurements of morphogen distribution have allowed us to subject this hypothesis to rigorous physical testing. In the early Drosophila embryo, measurements of the morphogen Dorsal, which is a transcription factor responsible for initiating the earliest zygotic patterns along the dorsal-ventral axis, have revealed a gradient that is too narrow to pattern the entire axis. In this study, we use a mathematical model of Dorsal dynamics, fit to experimental data, to determine the ability of the Dorsal gradient to regulate gene expression across the entire dorsal-ventral axis. We found that two assumptions are required for the model to match experimental data in both Dorsal distribution and gene expression patterns. First, we assume that Cactus, an inhibitor that binds to Dorsal and prevents it from entering the nuclei, must itself be present in the nuclei. And second, we assume that fluorescence measurements of Dorsal reflect both free Dorsal and Cactus-bound Dorsal. Our model explains the dynamic behavior of the Dorsal gradient at lateral and dorsal positions of the embryo, the ability of Dorsal to regulate gene expression across the entire dorsal-ventral axis, and the robustness of gene expression to stochastic effects. Our results have a general implication for interpreting fluorescence-based measurements of signaling molecules. PMID:25879657

  3. Asynchronous ripening behavior of cactus pear (Opuntia ficus-indica) cultivars with respect to physicochemical and physiological attributes.

    PubMed

    Kyriacou, M C; Emmanouilidou, M G; Soteriou, G A

    2016-11-15

    Physicochemical and physiological ripening events in cactus pear (Opuntia ficus-indica) fruit of cultivars 'Ntopia' and 'Hercules' were profiled against skin coloration from mature-green (S1) to over-mature (S5). Fructose and glucose accumulation were linear in 'Ntopia' but peaked near S3 in 'Hercules' synchronously to the appearance of sucrose. Betalains increased steadily in 'Ntopia' (103.2mg/l) but peaked before full skin coloration in 'Hercules' (49.7mg/l); whereas phenolic content remained invariable and ascorbate content peaked near S5 in both 'Ntopia' (108.6μg/g) and 'Hercules' (163.1μg/g). Cell wall material diminished with maturity though textural changes with ripening appeared not related to pectin solubilization but to weakening of glycan bonding and loss of neutral sugars. Fruit firmness rather was correlated to seed weight (r=0.89) and seed-to-pulp ratio (r=0.73). Cultivar differences highlighted in the chronology of ripening events are critical for defining optimum harvest maturity and postharvest handling protocols for premium quality cactus pear fruit.

  4. A new fission-fragment detector to complement the CACTUS-SiRi setup at the Oslo Cyclotron Laboratory

    NASA Astrophysics Data System (ADS)

    Tornyi, T. G.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Siem, S.; Krasznahorkay, A.; Csige, L.

    2014-02-01

    An array of Parallel Plate Avalanche Counters (PPAC) for the detection of heavy ions has been developed. The new device, NIFF (Nuclear Instrument for Fission Fragments), consists of four individual detectors and covers 60% of 2π. It was designed to be used in conjunction with the SiRi array of ΔE-E silicon telescopes for light charged particles and fits into the CACTUS array of 28 large-volume NaI scintillation detectors at the Oslo Cyclotron Laboratory. The low-pressure gas-filled PPACs are sensitive for the detection of fission fragments, but are insensitive to scattered beam particles of light ions or light-ion ejectiles. The PPAC detectors of NIFF have good time resolution and can be used either to select or to veto fission events in in-beam experiments with light-ion beams and actinide targets. The powerful combination of SiRi, CACTUS, and NIFF provides new research opportunities for the study of nuclear structure and nuclear reactions in the actinide region. The new setup is particularly well suited to study the competition of fission and γ decay as a function of excitation energy.

  5. The Dorsal/miR-1959/Cactus feedback loop facilitates the infection of WSSV in Litopenaeus vannamei.

    PubMed

    Xu, Xiaopeng; Yuan, Jia; Yang, Linwei; Weng, Shaoping; He, Jianguo; Zuo, Hongliang

    2016-09-01

    miR-1959, a novel microRNA identified from Litopenaeus vannamei, mediates a positive feedback loop between Dorsal and Cactus that can continuously maintain the activation of the NF-κB pathway. It has been known that miR-1959 is involved in antibacterial immunity in shrimp, but its function in antiviral responses is still unknown. In this study, we focused on the role of miR-1959 in infection of white spot syndrome virus (WSSV), the major viral pathogen in shrimp worldwide. The expression of miR-1959 in shrimp hemocytes, gill, and hepatopancreas was significantly up-regulated upon WSSV infection. Dual-luciferase reporter assays demonstrated that miR-1959 could enhance the activity of the promoter of WSSV immediate early gene ie1. In vivo experiments also showed that inhibition of miR-1959 led to decrease of the mortality of WSSV-infected shrimp and the genome copies of WSSV in tissues, meanwhile the expression of WSSV ie1 and VP28 genes was down-regulated. In contrast, increase of the miR-1959 level in shrimp by injection of miR-1959 mimics produced opposite results. These suggested that the Dorsal/miR-1959/Cactus feedback loop could favor the infection of WSSV in shrimp. Thus, our study helps further reveal the interaction between WSSV and shrimp immune system.

  6. Asynchronous ripening behavior of cactus pear (Opuntia ficus-indica) cultivars with respect to physicochemical and physiological attributes.

    PubMed

    Kyriacou, M C; Emmanouilidou, M G; Soteriou, G A

    2016-11-15

    Physicochemical and physiological ripening events in cactus pear (Opuntia ficus-indica) fruit of cultivars 'Ntopia' and 'Hercules' were profiled against skin coloration from mature-green (S1) to over-mature (S5). Fructose and glucose accumulation were linear in 'Ntopia' but peaked near S3 in 'Hercules' synchronously to the appearance of sucrose. Betalains increased steadily in 'Ntopia' (103.2mg/l) but peaked before full skin coloration in 'Hercules' (49.7mg/l); whereas phenolic content remained invariable and ascorbate content peaked near S5 in both 'Ntopia' (108.6μg/g) and 'Hercules' (163.1μg/g). Cell wall material diminished with maturity though textural changes with ripening appeared not related to pectin solubilization but to weakening of glycan bonding and loss of neutral sugars. Fruit firmness rather was correlated to seed weight (r=0.89) and seed-to-pulp ratio (r=0.73). Cultivar differences highlighted in the chronology of ripening events are critical for defining optimum harvest maturity and postharvest handling protocols for premium quality cactus pear fruit. PMID:27283673

  7. The Dorsal/miR-1959/Cactus feedback loop facilitates the infection of WSSV in Litopenaeus vannamei.

    PubMed

    Xu, Xiaopeng; Yuan, Jia; Yang, Linwei; Weng, Shaoping; He, Jianguo; Zuo, Hongliang

    2016-09-01

    miR-1959, a novel microRNA identified from Litopenaeus vannamei, mediates a positive feedback loop between Dorsal and Cactus that can continuously maintain the activation of the NF-κB pathway. It has been known that miR-1959 is involved in antibacterial immunity in shrimp, but its function in antiviral responses is still unknown. In this study, we focused on the role of miR-1959 in infection of white spot syndrome virus (WSSV), the major viral pathogen in shrimp worldwide. The expression of miR-1959 in shrimp hemocytes, gill, and hepatopancreas was significantly up-regulated upon WSSV infection. Dual-luciferase reporter assays demonstrated that miR-1959 could enhance the activity of the promoter of WSSV immediate early gene ie1. In vivo experiments also showed that inhibition of miR-1959 led to decrease of the mortality of WSSV-infected shrimp and the genome copies of WSSV in tissues, meanwhile the expression of WSSV ie1 and VP28 genes was down-regulated. In contrast, increase of the miR-1959 level in shrimp by injection of miR-1959 mimics produced opposite results. These suggested that the Dorsal/miR-1959/Cactus feedback loop could favor the infection of WSSV in shrimp. Thus, our study helps further reveal the interaction between WSSV and shrimp immune system. PMID:27492121

  8. Characterization of the nutritional components in fruit and cladode of selenium-enriched nutraceutical cactus pear fruit varieties grown on agricultural sediment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Different accessions of different colored cactus pear (Opuntia ficus Indica) were grown in soils high in salts, boron and selenium (Se) located in the Westside of central California. The changes in the nutritional status and biological transformation of the absorbed inorganic Se from the soils into ...

  9. Selenium accumulation, distribution and speciation in spineless prickly pear cactus: a salt, boron, and drought tolerant, selenium-enriched nutraceutical fruit crop.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prickly pear cactus (Opuntia) may be an alternative crop to grow in drainage-impacted regions of the westside of California, where high levels of salinity, selenium (Se), and boron (B) are present. Preliminary trials have demonstrated that Opuntia can tolerate the adverse soil conditions, while accu...

  10. Diversity and antifungal activity of the endophytic fungi associated with the native medicinal cactus Opuntia humifusa (Cactaceae) from the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The endophytic fungal community associated with the native cactus Opuntia humifusa in the United States was investigated and its potential for providing antifungal compounds. A total of 108 endophytic fungal isolates were obtained and identified by molecular methods into 17 different taxa of the gen...

  11. The Aerosol Coarse Mode: Its Importance for Light Scattering Enhancement and Columnar Optical Closure Studies

    NASA Astrophysics Data System (ADS)

    Zieger, P.

    2015-12-01

    Ambient aerosol particles can take up water and thus change their optical properties depending on the hygroscopicity and the relative humidity (RH) of the surrounding air. Knowledge of the hygroscopicity effect is of importance for radiative forcing calculations but is also needed for the comparison or validation of remote sensing or model results with in situ measurements. Specifically, the particle light scattering depends on RH and can be described by the scattering enhancement factor f(RH), which is defined as the particle light scattering coefficient at defined RH divided by its dry value. Here, we will present insights from measurements of f(RH) across Europe (Zieger et al., 2013) and will demonstrate why the coarse mode is important when modeling or predicting f(RH) from auxiliary aerosol in-situ measurements. We will show the implications by presenting the results of a recently performed columnar optical closure study (Zieger et al., 2015). This study linked ground-based in-situ measurements (with the help of airborne aerosol size distribution measurements) to columnar aerosol optical properties derived by a co-located AERONET sun photometer. The in situ derived aerosol optical depths (AOD) were clearly correlated with the directly measured values of the AERONET sun photometer but were substantially lower compared to the directly measured values (factor of ˜ 2-3). Differences became greater for longer wavelengths. The disagreement between in situ derived and directly measured AOD was hypothesized to originate from losses of coarse and fine mode particles through dry deposition within the forest's canopy and losses in the in situ sampling lines. In addition, elevated aerosol layers from long-range transport were observed for parts of the campaign which could have explained some of the disagreement. Zieger, P., Fierz-Schmidhauser, R., Weingartner, E., and Baltensperger, U.: Effects of relative humidity on aerosol light scattering: results from different

  12. Preliminary Assessment for CAU 485: Cactus Spring Ranch Pu and DU Site CAS No. TA-39-001-TAGR: Soil Contamination, Tonopah Test Range, Nevada

    SciTech Connect

    1998-07-01

    Corrective Action Unit 485, Corrective Action Site TA-39-001-TAGR, the Cactus Spring Ranch Soil Contamination Area, is located approximately six miles southwest of the Area 3 Compound at the eastern mouth of Sleeping Column Canyon in the Cactus Range on the Tonopah Test Range. This site was used in conjunction with animal studies involving the biological effects of radionuclides (specifically plutonium) associated with Operation Roofer Coaster. The location had been used as a ranch by private citizens prior to government control of the area. According to historical records, Operation Roofer Coaster activities involved assessing the inhalation uptake of plutonium in animals from the nonnuclear detonation of nuclear weapons. Operation Roofer Coaster consisted of four nonnuclear destruction tests of a nuclear device. The four tests all took place during May and June 1963 and consisted of Double Tracks and Clean Slate 1, 11, and 111. Eighty-four dogs, 84 burros, and 136 sheep were used for the Double Tracks test, and ten sheep and ten dogs were used for Clean Slate 11. These animals were housed at Cactus Spring Ranch. Before detonation, all animals were placed in cages and transported to the field. After the shot, they were taken to the decontamination area where some may have been sacrificed immediately. All animals, including those sacrificed, were returned to Cactus Spring Ranch at this point to have autopsies performed or to await being sacrificed at a later date. A description of the Cactus Spring Ranch activities found in project files indicates the ranch was used solely for the purpose of the Roofer Coaster tests and bioaccumulation studies and was never used for any other project. No decontamination or cleanup had been conducted at Cactus Spring Ranch prior to the start of the project. When the project was complete, the pits at Cactus Spring Ranch were filled with soil, and trailers where dogs were housed and animal autopsies had been performed were removed

  13. Ultra-fast in-situ X-ray studies of evolving columnar dendrites in solidifying steel weld pools

    NASA Astrophysics Data System (ADS)

    Mirihanage, W. U.; Di Michiel, M.; Mathiesen, R. H.

    2015-06-01

    High-brilliance polychromatic synchrotron radiation has been used to conduct in-situ studies of the solidification microstructure evolution during simulated welding. The welding simulations were realized by rapidly fusing ∼ 5 mm spot in Fe-Cr-Ni steel. During the solid- liquid-solid phase transformations, a section of the weld pool was placed in an incident 50-150 keV polychromatic synchrotron X-ray beam, in a near-horizontal position at a very low inclination angle. Multiple high-resolution 2D detectors with very high frame rates were utilized to capture time resolved X-ray diffraction data from suitably oriented solid dendrites evolving in the weld pool. Comprehensive analysis of the diffraction data revealed individual and overall dendritic growth characteristics and relevant melt and solid flow dynamics during weld pool solidification, which was completed within 1.5 s. Columnar dendrite tip velocities were estimated from the experimental data and during early stages of solidification were exceeded 4 mm/s. The most remarkable observation revealed through the time-resolved reciprocal space observations are correlated to significant tilting of columnar type dendrites at their root during solidification, presumably caused by convective currents in the weld pool. When the columnar dendrite tilting are transformed to respective metric linear tilting velocities at the dendrite tip; tilting velocities are found to be in the same order of magnitude as the columnar tip growth velocities, suggesting a highly transient nature of growth conditions.

  14. DNAk is a dominant epitope in the humoral immune response of channel catfish (Ictalurus punctatus) to Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccination remains a viable alternative for bacterial disease protection in fish; however additional work is required to understand the mechanisms of adaptive immunity in the channel catfish. To assess the humoral immune response to Flavobacterium columnare; a group of channel catfish were first im...

  15. Molecular typing of isolates of the fish pathogen, Flavobacterium columnare, by single-strand conformation polymorphism analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare intraspecies diversity was revealed by analyzing the 16S rRNA gene and the 16S-23S internal spacer region (ISR). Standard restriction fragment length polymorphism (RFLP) of these sequences was compared with single strand conformation polymorphism (SSCP). Diversity indexes sh...

  16. Lack of association between Flavobacterium columnare genomovar and virulence in hybrid tilapia Oreochromis niloticus (L.) x Oreochromis aureus (Steindachner)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Columnaris disease can be problematic in tilapia (Oreochromis spp.) production. An understanding of the pathogenesis and virulence of F. columnare is needed for the development of prevention strategies. The objective of this study was to determine the virulence of genetically defined isolates of Fl...

  17. Extremophile extracts and enhancement techniques show promise for the development of a live vaccine against Flavobacterium columnare

    USGS Publications Warehouse

    Powell, D.B.; Palm, R.C.; MacKenzie, A.P.; Winton, J.R.

    2009-01-01

    The effects of temperature, ionic strength, and new cryopreservatives derived from polar ice bacteria were investigated to help accelerate the development of economical, live attenuated vaccines for aquaculture. Extracts of the extremophile Gelidibacter algens functioned very well as part of a lyophilization cryoprotectant formulation in a 15-week storage trial. The bacterial extract and trehalose additives resulted in significantly higher colony counts of columnaris bacteria (Flavobacterium columnare) compared to nonfat milk or physiological saline at all time points measured. The bacterial extract combined with trehalose appeared to enhance the relative efficiency of recovery and growth potential of columnaris in flask culture compared to saline, nonfat milk, or trehalose-only controls. Pre-lyophilization temperature treatments significantly affected F. columnare survival following rehydration. A 30-min exposure at 0 ??C resulted in a 10-fold increase in bacterial survival following rehydration compared to mid-range temperature treatments. The brief 30 and 35 ??C pre-lyophilization exposures appeared to be detrimental to the rehydration survival of the bacteria. The survival of F. columnare through the lyophilization process was also strongly affected by changes in ionic strength of the bacterial suspension. Changes in rehydration constituents were also found to be important in promoting increased survival and growth. As the sodium chloride concentration increased, the viability of rehydrated F. columnare decreased. ?? 2009 Elsevier Inc.

  18. Intragenomic heterogeneity in the 16S rRNA genes of Flavobacterium columnare and relevance to genomovar assignment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic variability in 16S rRNA gene sequences has been demonstrated among isolates of Flavobacterium columnare and a restriction fragment length polymorphism (RFLP) assay is available for genetic typing this important fish pathogen. Interpretation of restriction patterns can be difficult due to th...

  19. Intragenomic heterogeneity in the 16S rRNA genes of Flavobacterium columnare and standard protocol for genomovar assignment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic variability in 16S rRNA gene sequences has been demonstrated among isolates of Flavobacterium columnare and a restriction fragment length polymorphism (RFLP) assay is available for genetic typing this important fish pathogen. Interpretation of restriction patterns can be difficult due to th...

  20. Evaluation of potassium permanganate against an experimental subacute infection of Flavobacterium columnare in channel catfish, Icatlurus punctatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experiment was performed to evaluate the efficacy of potassium permanganate (KMnO4) as a prophylactic and therapeutic treatment of an experimental subacute infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus. Fish were cutaneously abraded and divided into five treatment...

  1. Comparative effects of copper sulfate or potassium permanganate on channel catfish concurrently infected with Flavobacterium columnare and Ichthyobodo necator

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An opportunistic study was conducted to determine the effects of two chemical therapeutants on channel catfish (CCF) Ictalurus punctatus concurrently infected Flavobacterium columnare and Ichthyobodo necator. Copper sulfate (CuSO4) and potassium permanganate (KMnO4) were investigated for their abil...

  2. Identification and expresion profile of multiple genes in channel catfish fry ten minutes after modified live Flavobacterium columnare vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using PCR-select subtractive cDNA hybridization technique, 32 expressed sequence tags (ESTs) were isolated from 96 clones of a channel catfish (Ictalurus punctatus) fry subtractive library ten minutes post vaccination with a modified live Flavobacterum columnare vaccine. The transcription levels of ...

  3. FORWARD AND INVERSE BIO-GEOCHEMICAL MODELING OF MICROBIALLY INDUCED PRECIPITATION IN 0.5M COLUMNAR EXPERIMENTS

    SciTech Connect

    Tammer Barkouki; Brian Martinez; Brina Mortensen; Tess Weathers; Jason DeJong; Nic Spycher; Tim Ginn; Yoshiko Fujita; Robert Smith

    2009-09-01

    Microbial ureolysis-induced calcite precipitation may offer an in situ remediation for heavy metal and radionuclide contamination, as well as an alternative to traditional soil strengthening techniques. A microbially mediated calcite precipitation model was built in TOUGHREACT v2 and calibrated to batch and columnar experimental data. Kinetic ureolysis and calcite precipitation-rate expressions were parameterized by coupling TOUCHREACT with UCODE.

  4. Local and bulk melting of shocked columnar nanocrystalline Cu: Dynamics, anisotropy, premelting, superheating, supercooling, and re-crystallization.

    PubMed

    He, A M; Duan, S Q; Shao, J L; Wang, P; Luo, S N

    2013-08-21

    We perform large-scale molecular dynamics simulations to study shock-induced melting transition of idealized hexagonal columnar nanocrystalline Cu. The as-constructed nanocrystalline Cu consists of unrotated (reference) and rotated columnar crystals, relative to the columnar axis. Shock loading is applied along three principal directions of the columnar Cu: two transverse (zigzag and armchair) and one longitudinal directions. Dynamic local melting processes are highly anisotropic with respect to the shock directions. For the transverse directions, hotspot effect and disparate dynamic responses of grains with different orientations may lead to partial or complete premelting of the initially rotated grains, which in turn leads to transient supercooling and heterogeneous recrystallization, and thus, the formation of nanocrystalline solids with modified grain structures or solid-liquid mixtures, depending on the extent of supercooling. With increasing shock strengths, the reference grains melt heterogeneously at interfaces and homogeneously inside. Conversely, "bulk" premelting of the rotated grains is absent for the longitudinal direction, except for grain boundary melting. The progression of recrystallization or heterogenous melting diminishes and eventually eliminates the transient premelting or superheating of the system via latent heat and thermal diffusion. Premelting or superheating appears unlikely for bulk melting or well-defined Hugoniot states, if the thermal and mechanical equilibria are achieved, and the thermodynamic melting curve coincides with the partial melting Hugoniot states of a polycrystalline solid.

  5. Flavobacterium columnare type IX secretion system mutations result in defects in gliding motility and loss of virulence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gliding bacterium Flavobacterium columnare causes columnaris disease in wild and aquaculture-reared freshwater fish. The mechanisms responsible for columnaris disease are not known. The related bacterium Flavobacterium johnsoniae uses a type IX secretion system (T9SS) to secrete enzymes, adhesin...

  6. Isolation and characterization of Flavobacterium columnare (Bernardet et al. 2002) from four tropical fish species in Brazil.

    PubMed

    Pilarski, F; Rossini, A J; Ceccarelli, P S

    2008-05-01

    Flavobacterium columnare is the causative agent of columnaris disease in freshwater fish, implicated in skin and gill disease, often causing high mortality. The aim of this study was the isolation and characterization of Flavobacterium columnare in tropical fish in Brazil. Piracanjuba (Brycon orbignyanus), pacu (Piaractus mesopotamicus), tambaqui (Colossoma macropomum) and cascudo (Hypostomus plecostomus) were examined for external lesions showing signs of colunmaris disease such as greyish white spots, especially on the head, dorsal part and caudal fin of the fish. The sampling comprised 50 samples representing four different fish species selected for study. Samples for culture were obtained by skin and kidney scrapes with a sterile cotton swabs of columnaris disease fish and streaked onto Carlson and Pacha (1968) artificial culture medium (broth and solid) which were used for isolation. The strains in the liquid medium were Gram negative, long, filamentous, exhibited flexing movements (gliding motility), contained a large number of long slender bacteria and gathered into columns'. Strains on the agar produced yellow-pale colonies, rather small, flat that had rhizoid edges. A total of four Flavobacterium columnare were isolated: 01 Brycon orbignyanus strain, 01 Piaractus mesopotamicus strain, 01 Colossoma macropomum strain, and 01 Hypostomus plecostomus strain. Biochemical characterization, with its absorption of Congo red dye, production of flexirubin-type pigments, H2S production and reduction of nitrates proved that the isolate could be classified as Flavobacterium columnare.

  7. Enhancement of the photocatalytic property of TiO{sub 2} columnar nanostructured films by changing deposition angle

    SciTech Connect

    Li, Zhengcao Teng, Yi; Xing, Liping; Zhang, Na; Zhang, Zhengjun

    2014-02-01

    Highlights: • Isolated and inclined columnar TiO{sub 2} nanostructures were obtained by sputtering Ti, and subsequently annealing. • The film performed photocatalytic decolorization effectively under UV irradiation. • The photocatalytic efficiency increased with deposition angle, which results in a more porous micro structure of the films. - Abstract: Isolated and inclined columnar nanostructured TiO{sub 2} films were obtained by sputtering titanium with glancing angle deposition method and subsequently annealing in air. Compared with flat film, TiO{sub 2} film fabricated with this method has higher porosity; compared with TiO{sub 2} powder, it overcomes the obstacles of immobilization and recycling. The TiO{sub 2} photocatalysis was evaluated by the degradation of methyl orange under UV light. It was indicated that the photocatalytic performance increased with deposition angle, which changed the porosity of the films. The relationship between deposition angle (the angle between the target and substrate surface) and the TiO{sub 2} columnar inclination angle (the angle between TiO{sub 2} columnar and substrate normal) was discussed.

  8. Mitogenomic analysis of Montipora cactus and Anacropora matthai (cnidaria; scleractinia; acroporidae) indicates an unequal rate of mitochondrial evolution among Acroporidae corals

    NASA Astrophysics Data System (ADS)

    Tseng, Ching-Chih; Wallace, Carden C.; Chen, Chaolun Allen

    2005-11-01

    The complete nucleotide sequence of the mitochondrial (mt) genome was determined for specimens of the coral species Montipora cactus (Bernard 1897) and Anacropora matthai (Pillai 1973), representing two morphologically distinct genera of the family Acroporidae. These sequences were compared with the published mt genome sequence for the confamilial species, Acropora tenuis (Dana 1846). The size of the mt genome was 17,887 bp and 17,888 bp for M. cactus and A. matthai. Gene content and organization was found to be very similar among the three Acroporidae mt genomes with a group I intron occurring in the NADH dehyrogenase 5 ( nad5) gene. The intergenic regions were also similar in length among the three corals. The control region located between the small ribosomal RNA ( ms) and the cytochrome oxidase 3 ( cox3) gene was significantly smaller in M. cactus and A. matthai (both 627 bp) than in A. tenuis (1086 bp). Only one set of repeated sequences was identified at the 3'-end of the control regions in M. cactus and A. matthai. A lack of the abundant repetitive elements which have been reported for A. tenuis, accounts for the relatively short control regions in M. cactus and A. matthai. Pairwise distances and relative rate analyses of 13 protein coding genes, the group I intron and the largest intergenic region, igr3, revealed significant differences in the rate of molecular evolution of the mt genome among the three species, with an extremely slow rate being seen between Montipora and Anacropora. It is concluded that rapid mt genome evolution is taking place in genus Acropora relative to the confamilial genera Montipora and Anacropora although all are within the relatively slow range thought to be typical of Anthozoa.

  9. Coordinative nanoporous polymers synthesized with hydrogen-bonded columnar liquid crystals.

    PubMed

    Ishihara, Shinsuke; Furuki, Yusuke; Hill, Jonathan P; Ariga, Katsuhiko; Takeoka, Shinji

    2012-10-01

    In this paper, we report the development of nanoporous polymer which demonstrates the coordination property toward zinc porphyrin. A hydrogen-bonded columnar liquid crystalline precursor composed of a triphenylene template and three equivalent of the surrounding dendric amphiphile bearing a pyridyl head group and a polymerizable aliphatic chain, was covalently fixed by photopolymerization, and then the subsequent selective removal of the template successively resulted in a nanoporous polymer in which the pore wall is modified with pyridyl groups. The nanoporous polymer reflected the conformation of template, and displayed considerable coordination ability of the pyridyl groups towards zinc porphyrin. The coordinative nanoporous polymer is promising as a nano-scaled scaffold for the organization of dyes into functional supramolecular architectures.

  10. Solid-state acquisition of fingermark topology using dense columnar thin films.

    PubMed

    Lakhtakia, Akhlesh; Shaler, Robert C; Martín-Palma, Raúl J; Motyka, Michael A; Pulsifer, Drew P

    2011-05-01

    Various vacuum techniques are employed to develop fingermarks on evidentiary items. In this work, a vacuum was used to deposit columnar thin films (CTFs) on untreated, cyanoacrylate-fumed or dusted fingermarks on a limited selection of nonporous surfaces (microscope glass slides and evidence tape). CTF deposition was not attempted on fingermarks deposited on porous surfaces. The fingermarks were placed in a vacuum chamber with the fingermark side facing an evaporating source boat containing either chalcogenide glass or MgF(2). Thermal evaporation of chalcogenide glass or MgF(2) under a 1 μTorr vacuum for 30 min formed dense CTFs on fingermark ridges, capturing the topographical features. The results show that it is possible to capture fingermark topology using CTFs on selected untreated, vacuumed cyanoacrylate-fumed or black powder-dusted nonporous surfaces. Additionally, the results suggested this might be a mechanism to help elucidate the sequence of deposition.

  11. Optimized development of sebaceous fingermarks on nonporous substrates with conformal columnar thin films.

    PubMed

    Muhlberger, Sarah A; Pulsifer, Drew P; Lakhtakia, Akhlesh; Martín-Palma, Raúl J; Shaler, Robert C

    2014-01-01

    A form of physical vapor deposition, called the conformal-evaporated-film-by-rotation (CEFR) method, was optimized for the conformal deposition of columnar thin films (CTFs) on sebaceous fingermarks. Relying on the surface topology of the fingermark, the CTF development technique is different from traditional development techniques. After the optimization of the development conditions, the CTF development technique was found to be superior to traditional development methods on several nonporous substrates: the smooth side of Scotch(®) Multitask, Gorilla(®) , and Scotch(®) Duct tapes; clear and black soft plastics; stained and sealed walnut and cherry woods; partial bloody fingermarks on stainless steel; and discharged cartridge casings. It was equally as good as other development techniques on other substrates, but worse on a few. The optimization study is expected to assist in designing a mobile CEFR apparatus capable of on-scene development of fingermarks.

  12. The real structure of columnar pinning centers in heavy-ion-irradiated cuprate superconductors

    SciTech Connect

    Welch, D.O.; Zhu, Y.; Budhani, R.C.

    1995-12-31

    There has been considerable recent interest in the use of columnar defects produced by irradiation with energetic heavy ions to raise the irreversibility line and improve the critical current density of cuprate superconductors. In the interpretation and theoretical modeling of the flux-pinning characteristics of heavy-ion tracks, it is generally assumed that they are simply columns of non-superconducting material. In this paper we present a more realistic description, based both on resistivity measurements and on detailed, quantitative transmission electron microscope methods (both imaging and analytical studies), of the nature of heavy-ion damage, including defects, disorder, strain fields, and oxygen deficiencies in the matrix of the superconductor surrounding the amorphous columns. The presence of such disorder appears to be a consequence of the mechanism of track formation, which involves partial epitaxial regrowth of a molten region which follows the passage of sufficiently energetic ions.

  13. Significance of acid-mucin-positive nongoblet columnar cells in the distal esophagus and gastroesophageal junction.

    PubMed

    Chen, Y Y; Wang, H H; Antonioli, D A; Spechler, S J; Zeroogian, J M; Goyal, R; Shahsafaei, A; Odze, R D

    1999-12-01

    Acidic mucin-positive nongoblet columnar cells (NGCC) have recently been observed in the surface epithelium of the gastroesophageal junction (GEJ) and distal esophagus in resections from patients with traditional long segment (>3 cm) Barrett's esophagus (BE). However, the significance of finding acidic mucin-positive NGCC in the surface epithelium of biopsy specimens from the distal esophagus/GEJ region in the absence of goblet cells (GC) remains unknown. Therefore, to determine the significance of mucin histochemical changes in the distal esophagus/GEJ region, we analyzed and compared the types, prevalence, and distribution of neutral and acidic mucins in biopsy specimens obtained from 2 groups of patients: those with (32 patients) and those without (107 patients) GC identified in this area. Various mucin histochemical stains (PAS-Ab pH 2.5, HID-Ab pH 2.5, PB/KOH/PAS) were used to identify neutral mucins, acidic mucins (sialomucins and sulphomucins), and o-acetylated sialomucins. The results were compared between the 2 patient groups and correlated with the clinical, endoscopic, and pathologic features. Compared with patients without GC, patients with GC had a significantly higher male/female ratio and a higher proportion of patients with greater than 3 cm of columnar epithelium within the esophagus. Acidic mucin (sialomucin and sulphomucin)-positive NGCC in the surface, foveolar, and glandular epithelium did not show any correlation with any of the clinical, endoscopic, or pathologic features, such as esophagitis, carditis, antritis, Helicobacter pylori infection, or length of columnar epithelium in the distal esophagus. However, acidic mucin-positive NGCC correlated strongly with the presence of GC (P < .001). For example, sialomucin-positive NGCC were present in 28 of 32 (88%) patients with GC compared with 31 of 107 (29%) patients without GC (P < .001). Similarly, sulphomucin-positive NGCC were present in 20 of 32 (62%) patients with GC, compared with 11 of

  14. Functional morphology and biomechanics of branch-stem junctions in columnar cacti.

    PubMed

    Schwager, Hannes; Masselter, Tom; Speck, Thomas; Neinhuis, Christoph

    2013-12-01

    Branching in columnar cacti features morphological and anatomical characteristics specific to the subfamily Cactoideae. The most conspicuous features are the pronounced constrictions at the branch-stem junctions, which are also present in the lignified vascular structures within the succulent cortex. Based on finite-element analyses of ramification models, we demonstrate that these indentations in the region of high flexural and torsional stresses are not regions of structural weakness (e.g. allowing vegetative propagation). On the contrary, they can be regarded as anatomical adaptations to increase the stability by fine-tuning the stress state and stress directions in the junction along prevalent fibre directions. Biomimetic adaptations improving the functionality of ramifications in technical components, inspired, in particular, by the fine-tuned geometrical shape and arrangement of lignified strengthening tissues of biological role models, might contribute to the development of alternative concepts for branched fibre-reinforced composite structures within a limited design space.

  15. Functional morphology and biomechanics of branch–stem junctions in columnar cacti

    PubMed Central

    Schwager, Hannes; Masselter, Tom; Speck, Thomas; Neinhuis, Christoph

    2013-01-01

    Branching in columnar cacti features morphological and anatomical characteristics specific to the subfamily Cactoideae. The most conspicuous features are the pronounced constrictions at the branch–stem junctions, which are also present in the lignified vascular structures within the succulent cortex. Based on finite-element analyses of ramification models, we demonstrate that these indentations in the region of high flexural and torsional stresses are not regions of structural weakness (e.g. allowing vegetative propagation). On the contrary, they can be regarded as anatomical adaptations to increase the stability by fine-tuning the stress state and stress directions in the junction along prevalent fibre directions. Biomimetic adaptations improving the functionality of ramifications in technical components, inspired, in particular, by the fine-tuned geometrical shape and arrangement of lignified strengthening tissues of biological role models, might contribute to the development of alternative concepts for branched fibre-reinforced composite structures within a limited design space. PMID:24132310

  16. Staged Columnar Fixation of Bicondylar Tibial Plateaus: A Cheaper Alternative to External Fixation.

    PubMed

    Perdue, Aaron; Greenberg, Sarah E; Sathiyakumar, Vasanth; Thakore, Rachel V; Mir, Hassan R; Obremskey, William T; Sethi, Manish K

    2016-01-01

    The objective of this study was to compare complication rates and costs of staged columnar fixation (SCF) to external fixation for bicondylar tibial plateau fractures. Patients who received SCF or temporary external fixation across a 3-year period at a major level I trauma center underwent a retrospective chart review for associated complications. Fisher's exact analysis was used to determine any statistical difference in complication rates between both groups. However, there was no significant difference in complication rates between the SCF and external fixator groups. Average medial plate costs for SCF were $2131 compared with an average external fixator cost of $4070 (p < .0001). Given that all patients with external fixation undergo eventual medial and lateral plating, savings with SCF include $4070 plus operative costs for removing the fixator. As our health care system focuses on cost-cutting efforts, orthopaedic trauma surgeons must explore cheaper and equally effective treatment alternatives. PMID:27082883

  17. Order induced charge carrier mobility enhancement in columnar liquid crystal diodes.

    PubMed

    Eccher, Juliana; Faria, Gregório C; Bock, Harald; von Seggern, Heinz; Bechtold, Ivan H

    2013-11-27

    Discotic molecules comprising a rigid aromatic core and flexible side chains have been promisingly applied in OLEDs as self-organizing organic semiconductors. Due to their potentially high charge carrier mobility along the columns, device performance can be readily improved by proper alignment of columns throughout the bulk. In the present work, the charge mobility was increased by 5 orders of magnitude due to homeotropic columnar ordering induced by the boundary interfaces during thermal annealing in the mesophase. State-of-the-art diodes were fabricated using spin-coated films whose homeotropic alignment with formation of hexagonal germs was observed by polarizing optical microscopy. The photophysical properties showed drastic changes at the mesophase-isotropic transition, which is supported by the gain of order observed by X-ray diffraction. The electrical properties were investigated by modeling the current-voltage characteristics by a space-charge-limited current transport with a field dependent mobility. PMID:24191748

  18. Isolation and characterization of Flavobacterium columnare from freshwater ornamental goldfish Carassius auratus.

    PubMed

    Verma, Dev Kumar; Rathore, Gaurav; Pradhan, Pravata Kumar; Sood, Neeraj; Punia, Peyush

    2015-03-01

    Filamentous bacteria overlaying ulcerated area on the body surface were observed in the wet-mout preparation from a moribund goldfish with saddle back appearance. The causative agent was identified as Flavobacterium columnrae, on the basis of biochemical test, species-specific polymerase chain reaction (PCR) and sequencing of 16S rDNA gene with the universal bacterial primers. Furthermore, the strain (ING-1) attributed to genomovar II in 16S rDNA PCR-restriction fragment length polymorphism (PCR-RFLP) and sequence analysis. In phylogenetic analysis, the strain ING-1, produced typical columnaris disease symptoms in rohu (Labeo rohita) fingerlings within 10 days. This is a new record about molecular detection and identification of Flavobacterium columnare, occurring naturally on a new host Carassius auratusin India. PMID:25895267

  19. Hall Scaling behavior of Hg- and Tl-based superconducting thin films with columnar defects

    NASA Astrophysics Data System (ADS)

    Kang, W. N.; Chu, C. W.; Kim, D. H.; Lee, J. U.

    1998-03-01

    We have measured the mixed-state Hall effects of HgBa_2CaCu_2O_6+δ, HgBa_2Ca_2Cu_3O_8+δ, and Tl_2Ba_2CaCu_2O_8+δ thin films with columnar defects. We found the field-independent scaling behavior between the Hall resistivity(ρ_xy) and longitudinal resistivityρ_xx for low and high field regimes. The Hall scaling exponent β in ρ_xy = Aρ_xx^β showed 1.0 ± 0.1 for low field regions, while β showed 2.0 ± 0.05 for high field regions. The observation of β = 1.0 in the low field limits is consistent with the recent theory which is based on the d-wave superconductors. The result will be discussed in the context of the Hall scaling behavior in 2- or 3-dimensional-like systems.

  20. An analytical model for solute redistribution during solidification of planar, columnar, or equiaxed morphology

    NASA Astrophysics Data System (ADS)

    Nastac, L.; Stefanescu, D. M.

    1993-09-01

    Existing models for solute redistribution (microsegregation) during solidification were reviewed. There are no analytical models that take into account limited diffusion in both the liquid and the solid phases. A new analytical mathematical model for solute redistribution was developed. Diffusion in liquid and in solid was considered. This model does not require a prescribed movement of the interface. It can be used for one-dimensional (1-D) (plate), two-dimensional (cylinder), or three-dimensional (3-D) (sphere) calculations. Thus, it is possible to calculate microsegregation at the level of primary or secondary arm spacing for columnar dendrites or for equiaxed dendrites. The solution was compared with calculations based on existing models, as well as with some available experimental data for the segregation of base elements in as cast Al-4. 9 wt pct Cu, INCONEL 718, 625, and plain carbon (0. 13 wt pct C) steel.

  1. Induction of columnar and smectic phases for spiropyran derivatives: effects of acidichromism and photochromism.

    PubMed

    Tan, Boon-Hooi; Yoshio, Masafumi; Kato, Takashi

    2008-03-01

    Liquid-crystalline (LC) properties have been induced in a number of spiropyran derivatives by the addition of methanesulfonic acid. Spiropyran derivatives containing one or two gallic acid moieties with one, two, or three long alkyl chains were prepared. Acid-induced spiro-protonated-merocyanine isomerization induced mesomorphism for these materials. Equimolar mixtures of methanesulfonic acid and the spiropyran derivatives with one or two dodecyloxy chains exhibited smectic A phases, whereas the spiropyran derivatives containing the gallic acid moiety with three dodecyloxy chains showed hexagonal columnar phases. On the contrary, photoirradiation of the spiropyran compounds in the bulk liquid state did not lead to the induction of mesomorphism, although the merocyanine form was induced. These results suggest that these merocyanine derivatives with ionic and nonionic moieties cannot simply form nanosegregated LC structures. Complex formation of the merocyanine form with methanesulfonic acid may play a key role in the formation of LC molecular assemblies.

  2. Comparison of Columnar Water-Vapor Measurements from Solar Transmittance Methods

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Michalsky, J.; Slater, Donald W.; Barnard, James C.; Halthore, Rangasayi N.; Liljegren, James C.; Holben, Brent N.; Eck, Thomas F.; Livingston, John M.; Russell, Philp B.

    2001-01-01

    The Atmospheric Radiation Measurement program studied water vapor abundance measurement at its southern Great Plains site in the fall of 1997. The program used a large number of instruments, including four solar radiometers. By measuring solar transmittance in the 0.94 micrometer water apor absorption band, they were able to measure columnar water vapor (CWV). In the second round of comparison we used the same radiative transfer model, and the same line-by-line code (which includes recently corrected H2O spectroscopy) to retrieve CWV from all four solar radiometers, thus decreasing the mean CWV by 8 - 13 %. The model was not responsible for the 8 % spread in CWV which remained.

  3. Light-melt adhesive based on dynamic carbon frameworks in a columnar liquid-crystal phase

    NASA Astrophysics Data System (ADS)

    Saito, Shohei; Nobusue, Shunpei; Tsuzaka, Eri; Yuan, Chunxue; Mori, Chigusa; Hara, Mitsuo; Seki, Takahiro; Camacho, Cristopher; Irle, Stephan; Yamaguchi, Shigehiro

    2016-07-01

    Liquid crystal (LC) provides a suitable platform to exploit structural motions of molecules in a condensed phase. Amplification of the structural changes enables a variety of technologies not only in LC displays but also in other applications. Until very recently, however, a practical use of LCs for removable adhesives has not been explored, although a spontaneous disorganization of LC materials can be easily triggered by light-induced isomerization of photoactive components. The difficulty of such application derives from the requirements for simultaneous implementation of sufficient bonding strength and its rapid disappearance by photoirradiation. Here we report a dynamic molecular LC material that meets these requirements. Columnar-stacked V-shaped carbon frameworks display sufficient bonding strength even during heating conditions, while its bonding ability is immediately lost by a light-induced self-melting function. The light-melt adhesive is reusable and its fluorescence colour reversibly changes during the cycle, visualizing the bonding/nonbonding phases of the adhesive.

  4. Electrochemistry of surfactant-doped polypyrrole film(I): Formation of columnar structure by electropolymerization

    SciTech Connect

    Naoi, Katsuhiko; Oura, Yasushi; Maeda, Michiko; Nakamura, Sadako

    1995-02-01

    Electroactive polypyrrole (PPy) films have been studied widely in the field of applied material science for high energy/power storage applications. Perpendicularly oriented columnar structure was obtained for electropolymerized polypyrrole films formed from micellar solution of anionic surfactants. The surfactants used as dopants were a class of anionic surfactant, namely, Na salts of dodecyl sulfate (SDS) and dodecylbenzene sulfonate (SDBS). The formation process of polypyrrole films on electrode surfaces was studied with in situ atomic force microscopy (AFM) and electrochemical quartz crystal microbalance (EQCM) methods to monitor the structure of the grown polymers. In EQCM measurement, the frequency shift ({Delta}f) and the resonance resistance ({Delta}R) of the quartz crystal electrode were obtained simultaneously. An abrupt increase in {Delta}R was observed for both PPy/DS and PPy/DBS films at about 60--100mC/cm{sup 2}. Such a drastic change in {Delta}R, which may be associated with the emergence of the viscoelastic properties of the films, could be explained by the formation of columnar structure. In situ AFM observation clearly indicated that such a structure started to form around these critical charges. The cyclic voltammograms for the PPy/DS and PPy/DBS{sup {minus}} films showed sharp redox couples observed around {minus}0.5 to 0.6 V. The diffusion rate of cations for the resulting films was studied with ac impedance measurement as a function of the concentration of surfactant dopants. As the PPy film was prepared in higher concentration of the surfactant dopant, where the micelles are formed in solution, the resulting film showed a considerably higher (ca. 3 orders of magnitude) diffusion coefficient compared to ordinary PPy films so far reported. Such an enhanced diffusivity of ions could be attributed to a special formation process of polypyrrole in micelle solution: the mechanism is discussed here.

  5. Columnar interactions determine horizontal propagation of recurrent network activity in neocortex

    PubMed Central

    Wester, Jason C.; Contreras, Diego

    2012-01-01

    The cortex is organized in vertical and horizontal circuits that determine the spatiotemporal properties of distributed cortical activity. Despite detailed knowledge of synaptic interactions among individual cells in the neocortex, little is known about the rules governing interactions among local populations. Here we used self-sustained recurrent activity generated in cortex, also known as up-states, in rat thalamocortical slices in vitro to understand interactions among laminar and horizontal circuits. By means of intracellular recordings and fast optical imaging with voltage sensitive dyes, we show that single thalamic inputs activate the cortical column in a preferential L4→L2/3→L5 sequence, followed by horizontal propagation with a leading front in supra and infragranular layers. To understand the laminar and columnar interactions, we used focal injections of TTX to block activity in small local populations, while preserving functional connectivity in the rest of the network. We show that L2/3 alone, without underlying L5, does not generate self-sustained activity and is inefficient propagating activity horizontally. In contrast, L5 sustains activity in the absence of L2/3 and is necessary and sufficient to propagate activity horizontally. However, loss of L2/3 delays horizontal propagation via L5. Finally, L5 amplifies activity in L2/3. Our results show for the first time that columnar interactions between supra and infragranular layers are required for the normal propagation of activity in the neocortex. Our data suggest that supra and infragranular circuits with their specific and complex set of inputs and outputs, work in tandem to determine the patterns of cortical activation observed in vivo. PMID:22514308

  6. Chemopreventive effect of cactus Opuntia ficus indica on oxidative stress and genotoxicity of aflatoxin B1

    PubMed Central

    2011-01-01

    Background Aflatoxin B1 (AFB1) is potent hepatotoxic and hepatocarcinogenic agent. In aflatoxicosis, oxidative stress is a common mechanism contributing to initiation and progression of hepatic damage. The aim of this work was to evaluate the hepatoprotective effect of cactus cladode extract (CCE) on aflatoxin B1-induced liver damage in mice by measuring malondialdehyde (MDA) level, the protein carbonyls generation and the heat shock proteins Hsp 70 and Hsp 27 expressions in liver. We also looked for an eventual protective effect against AFB1-induced genotoxicity as determined by chromosome aberrations test, SOS Chromotest and DNA fragmentation assay. We further evaluated the modulation of p53, bax and bcl2 protein expressions in liver. Methods Adult, healthy balbC (20-25 g) male mice were pre-treated by intraperitonial administration of CCE (50 mg/Kg.b.w) for 2 weeks. Control animals were treated 3 days a week for 4 weeks by intraperitonial administration of 250 μg/Kg.b.w AFB1. Animals treated by AFB1 and CCE were divided into two groups: the first group was administrated CCE 2 hours before each treatment with AFB1 3 days a week for 4 weeks. The second group was administrated without pre-treatment with CCE but this extract was administrated 24 hours after each treatment with AFB1 3 days a week for 4 weeks. Results Our results clearly showed that AFB1 induced significant alterations in oxidative stress markers. In addition, it has a genotoxic potential and it increased the expression of pro apoptotic proteins p53 and bax and decreased the expression of bcl2. The treatment of CCE before or after treatment with AFB1, showed (i) a total reduction of AFB1 induced oxidative damage markers, (ii) an anti-genotoxic effect resulting in an efficient prevention of chromosomal aberrations and DNA fragmentation compared to the group treated with AFB1 alone (iii) restriction of the effect of AFB1 by differential modulation of the expression of p53 which decreased as well as its

  7. Dactylogyrus intermedius parasitism enhances Flavobacterium columnare invasion and alters immune-related gene expression in Carassius auratus.

    PubMed

    Zhang, Chao; Li, Dong-liang; Chi, Cheng; Ling, Fei; Wang, Gao-xue

    2015-09-17

    The monogenean Dactylogyrus intermedius and the bacterium Flavobacterium columnare are 2 common pathogens in aquaculture. The objective of the present study was to examine the effect of prior parasitism by D. intermedius on the susceptibility of goldfish to F. columnare and to explore the potential immune mechanisms related to the parasite infection. A F. columnare challenge trial was conducted between D. intermedius-parasitized and non-parasitized goldfish. The F. columnare load in gill, kidney, spleen and liver were compared. The expression of immune-related genes (IL-1β2, TNF-α1, TGF-β, iNOS-a, C3 and Lyz) in gill and kidney of D. intermedius-only infected and uninfected control fish were evaluated. D. intermedius-parasitized goldfish exhibited higher mortality and significantly higher loads (3051 to 537,379 genome equivalents [GEs] mg(-1)) of F. columnare, which were 1.13 to 50.82-fold higher than non-parasitized fish (389 to 17,829 GEs mg(-1)). Furthermore, the immune genes IL-1β2, TNF-α1, iNOS-a and Lyz were up-regulated while the TGF-β and C3 were down-regulated in the gill and kidney of parasite-infected fish compared to the non-parasitized controls. The down-regulation TGF-β and C3 was especially noteworthy, as this might indicate the suppression of the host immune functions due to the parasitism by D. intermedius. Taken together, these data demonstrate that parasite infection can enhance bacterial invasion and presents a hypothesis, based on gene expression data, that modulation of host immune response could play a role.

  8. Growth and development of the arborescent cactus Stenocereus queretaroensis in a subtropical semiarid environment, including effects of gibberellic acid.

    PubMed

    Pimienta, Eulogio; Hernandez, Gerardo; Domingues, Alejandro; Nobel, Park S.

    1998-01-01

    In Stenocereus queretaroensis (Weber) Buxbaum, an arborescent cactus cultivated in Jalisco, Mexico, for its fruits but studied here in wild populations, stem extension occurred in the autumn at the beginning of the dry season, flowering and fruiting occurred in the spring at the end of the dry season, and new roots grew in the summer during the wet season. The asynchrony of vegetative and reproductive growth reduces competitive sink effects, which may be advantageous for wild populations growing in infertile rocky soils. Seasonal patterns of sugars in the roots and especially the stems of S. queretaroensis were closely related to the main phenological stages, becoming lower in concentration during periods of major stem extension. Cessation of stem extension occurred in 100-year-old plants for which injection of GA(3) reinitiated such growth. Isolated chlorenchyma cylinders had maximum extension in a bathing solution containing 0.1 &mgr;M gibberellic acid.

  9. Genetic variability of an unusual apomictic triploid cactus--Haageocereus tenuis Ritter--from the Coast of Central Peru.

    PubMed

    Arakaki, Mónica; Speranza, Pablo; Soltis, Pamela S; Soltis, Douglas E

    2013-01-01

    Haageocereus tenuis is a prostrate cactus restricted to a small area of 2 km(2) near the city of Lima, Peru. The species is triploid and propagates mainly through stem fragmentation. In addition, propagation via agamospermy is documented and adventitious embryony is also inferred as a mechanism. Although seedling recruitment has not been observed in nature, we have shown that asexually produced seeds are viable. About 45 adult individuals, plus 9 individuals obtained from seeds, were sampled and 5 microsatellite markers were used to assess genetic variability. Microsatellite analysis confirms that individuals from the only existing population are genetically identical and that the population likely represents a single clone. The absence of mutations in any individual, even in highly variable microsatellite loci, may indicate that the species is also of recent origin. Other prostrate species of Haageocereus are suspected to be occasional apomicts. This phenomenon has significant implications for the evolutionary biology and ecology of Haageocereus and other clonal Cactaceae.

  10. Lead poisoning of bald (Haliaeetus leucocephalus) and golden (Aquila chrysaetos) eagles in the U.S. inland Pacific northwest region--an 18-year retrospective study: 1991-2008.

    PubMed

    Stauber, Erik; Finch, Nickol; Talcott, Patricia A; Gay, John M

    2010-12-01

    To determine risk factors and seasonal trends of lead poisoning in bald (Haliaeetus leucocephalus) and golden (Aquila chrysaetos) eagles, blood lead levels were evaluated in eagles admitted from the inland Pacific Northwest region of the United States to the Raptor Rehabilitation Program, College of Veterinary Medicine at Washington State University from 1991 to 2008. Admissions were from Washington (32 bald eagles, 27 golden eagles), northern Idaho (21 bald eagles, 25 golden eagles), northeastern Oregon (5 bald eagles, 6 golden eagles), Montana (2 bald eagles), Alaska (1 bald eagle), and unrecorded (6 bald eagles, 5 golden eagles). In these birds, 48% (22/46) of bald and 62% (31/50) of golden eagles tested had blood lead levels considered toxic by current standards. Of the bald and golden eagles with toxic lead levels, 91% (20/22) and 58% (18/31) respectively, were admitted after the end of the general deer and elk hunting seasons in December. Coyote hunting intensifies with the end of the large game hunting seasons and coyote carcasses left in the field and contaminated with lead bullet fragments become readily available food sources, exposing scavenging bald and golden eagles to high risk of acute lead poisoning.

  11. Lead poisoning of bald (Haliaeetus leucocephalus) and golden (Aquila chrysaetos) eagles in the U.S. inland Pacific northwest region--an 18-year retrospective study: 1991-2008.

    PubMed

    Stauber, Erik; Finch, Nickol; Talcott, Patricia A; Gay, John M

    2010-12-01

    To determine risk factors and seasonal trends of lead poisoning in bald (Haliaeetus leucocephalus) and golden (Aquila chrysaetos) eagles, blood lead levels were evaluated in eagles admitted from the inland Pacific Northwest region of the United States to the Raptor Rehabilitation Program, College of Veterinary Medicine at Washington State University from 1991 to 2008. Admissions were from Washington (32 bald eagles, 27 golden eagles), northern Idaho (21 bald eagles, 25 golden eagles), northeastern Oregon (5 bald eagles, 6 golden eagles), Montana (2 bald eagles), Alaska (1 bald eagle), and unrecorded (6 bald eagles, 5 golden eagles). In these birds, 48% (22/46) of bald and 62% (31/50) of golden eagles tested had blood lead levels considered toxic by current standards. Of the bald and golden eagles with toxic lead levels, 91% (20/22) and 58% (18/31) respectively, were admitted after the end of the general deer and elk hunting seasons in December. Coyote hunting intensifies with the end of the large game hunting seasons and coyote carcasses left in the field and contaminated with lead bullet fragments become readily available food sources, exposing scavenging bald and golden eagles to high risk of acute lead poisoning. PMID:21302758

  12. Floral visitation by the Argentine ant reduces pollinator visitation and seed set in the coast barrel cactus, Ferocactus viridescens.

    PubMed

    LeVan, Katherine E; Hung, Keng-Lou James; McCann, Kyle R; Ludka, John T; Holway, David A

    2014-01-01

    Mounting evidence indicates that trade-offs between plant defense and reproduction arise not only from resource allocation but also from interactions among mutualists. Indirect costs of plant defense by ants, for example, can outweigh benefits if ants deter pollinators. Plants can dissuade ants from occupying flowers, but such arrangements may break down when novel ant partners infiltrate mutualisms. Here, we examine how floral visitation by ants affects pollination services when the invasive Argentine ant (Linepithema humile) replaces a native ant species in a food-for-protection mutualism with the coast barrel cactus (Ferocactus viridescens), which, like certain other barrel cacti, produces extrafloral nectar. We compared the effects of floral visitation by the Argentine ant with those of the most prevalent native ant species (Crematogaster californica). Compared to C. californica, the Argentine ant was present in higher numbers in flowers. Cactus bees (Diadasia spp.), the key pollinators in this system, spent less time in flowers when cacti were occupied by the Argentine ant compared to when cacti were occupied by C. californica. Presumably as a consequence of decreased duration of floral visits by Diadasia, cacti occupied by L. humile set fewer seeds per fruit and produced fewer seeds overall compared to cacti occupied by C. californica. These data illustrate the importance of mutualist identity in cases where plants balance multiple mutualisms. Moreover, as habitats become increasingly infiltrated by introduced species, the loss of native mutualists and their replacement by non-native species may alter the shape of trade-offs between plant defense and reproduction.

  13. A global climatology of total columnar water vapour from SSM/I and MERIS

    NASA Astrophysics Data System (ADS)

    Lindstrot, R.; Stengel, M.; Schröder, M.; Fischer, J.; Preusker, R.; Schneider, N.; Steenbergen, T.; Bojkov, B. R.

    2014-06-01

    A global time series of total columnar water vapour from combined data of the Medium Resolution Imaging Spectrometer (MERIS) onboard ESA's Environmental Satellite (ENVISAT) and the Special Sensor Microwave/Imager (SSM/I) onboard the satellite series of the US Defense Meteorological Satellite Program (DMSP) is presented. The unique data set, generated in the framework of the ESA Data User Element (DUE) GlobVapour project, combines atmospheric water vapour observations over land and ocean, derived from measurements in the near-infrared and the microwave range, respectively. Daily composites and monthly means of total columnar water vapour are available as global maps on rectangular latitude-longitude grids with a spatial resolution of 0.05° × 0.05° over land and 0.5° × 0.5° over ocean for the years 2003 to 2008. The data are stored in NetCDF files and is fully compliant with the NetCDF Climate Forecast convention. Through the combination of high-quality microwave observations and near-infrared observations over ocean and land surfaces, respectively, the data set provides global coverage. The combination of both products is carried out such that the individual properties of the microwave and near-infrared products, in particular their uncertainties, are not modified by the merging process and are therefore well defined. Due to the global coverage and the provided uncertainty estimates this data set is potentially of high value for climate research. The SSM/I-MERIS TCWV data set is freely available via the GlobVapour project web page (www.globvapour.info) with associated doi:10.5676/DFE/WV_COMB/FP. In this paper, the details of the data set generation, i.e. the satellite data used, the retrieval techniques and merging approaches, are presented. The derived level 3 products are compared to global radiosonde data from the GCOS upper air

  14. Supramolecular Columnar Liquid Crystals with Tapered-Shape Simple Pyrazoles Obtained by Efficient Henry/Michael Reactions.

    PubMed

    Blanco, Hugo; Iguarbe, Verónica; Barberá, Joaquín; Serrano, José Luis; Elduque, Anabel; Giménez, Raquel

    2016-03-24

    A straightforward synthesis of mesogenic pyrazoles starting from benzaldehydes by a combination of efficient Henry and Michael reactions led to novel supramolecular liquid crystals. The mesogens are fluorescent 3,5-dimethyl-4-(di or trialkoxyphenyl)pyrazoles and, in spite of the tapered shape of these molecules and their structural simplicity (only one phenyl ring), columnar liquid-crystal phases were formed that are stable at room temperature. The self-assembled structure was studied by XRD and the columnar cross section contains two molecules on average with an antiparallel arrangement of pyrazoles interacting through hydrogen bonds. In contrast, the single-crystal structure of a trimethoxy analog did not show hydrogen-bonded pyrazoles but chains of head-to-tail arranged molecules.

  15. Comparison of the columnar-thin-film and vacuum-metal-deposition techniques to develop sebaceous fingermarks on nonporous substrates.

    PubMed

    Williams, Stephanie F; Pulsifer, Drew P; Shaler, Robert C; Ramotowski, Robert S; Brazelle, Shelly; Lakhtakia, Akhlesh

    2015-03-01

    Both the columnar-thin-film (CTF) and the vacuum-metal-deposition (VMD) techniques for visualizing sebaceous fingermarks require the deposition of a material thereon in a vacuum chamber. Despite that similarity, there are many differences between the two techniques. The film deposited with the CTF technique has a columnar morphology, but the film deposited with the VMD technique comprises discrete islands. A split-print methodology on a variety of fingermarked substrates was used to determine that the CTF technique is superior for developing fingermarks on clear sandwich bags and partial bloody fingermarks on stainless steel. Both techniques are similar in their ability to develop fingermarks on glass but the CTF technique yields higher contrast. The VMD technique is superior for developing fingermarks on white grocery bags and the smooth side of Gloss Finish Scotch Multitask(™) tape. Neither technique worked well for fingermarks on black garbage bags.

  16. Optimizing modulation frequency for structured illumination in a fiber-optic microendoscope to image nuclear morphometry in columnar epithelium.

    PubMed

    Keahey, P A; Tkaczyk, T S; Schmeler, K M; Richards-Kortum, R R

    2015-03-01

    Fiber-optic microendoscopes have shown promise to image the changes in nuclear morphometry that accompany the development of precancerous lesions in tissue with squamous epithelium such as in the oral mucosa and cervix. However, fiber-optic microendoscopy image contrast is limited by out-of-focus light generated by scattering within tissue. The scattering coefficient of tissues with columnar epithelium can be greater than that of squamous epithelium resulting in decreased image quality. To address this challenge, we present a small and portable microendoscope system capable of performing optical sectioning using structured illumination (SI) in real-time. Several optical phantoms were developed and used to quantify the sectioning capabilities of the system. Columnar epithelium from cervical tissue specimens was then imaged ex vivo, and we demonstrate that the addition of SI achieves higher image contrast, enabling visualization of nuclear morphology.

  17. Simulation of thermos-solutal convection induced macrosegregation in a Sn-10%Pb alloy benchmark during columnar solidification

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Wu, M.; Kharicha, A.; Ludwig, A.

    2016-03-01

    In order to investigate the effect of thermo-solutal convection on the formation of macrosegregation during columnar solidification, simulations with a liquid-columnar two phase model were carried out on a 2D rectangular benchmark of Sn-10%Pb alloy. The solidification direction in the benchmark is unidirectional: (') downwards from top to bottom or (2) upwards from bottom to top. Thermal expansion coefficient, solutal expansion coefficient and liquid diffusion coefficient of the melt are found to be key factors influencing the final macrosegregation. The segregation range and distribution are also strongly influenced by the benchmark configurations, e.g. the solidifying direction (upwards or downwards) and boundary conditions, et al. The global macrosegregation range increases with the velocity magnitude of the melt during the process of solidification.

  18. Effects of film thickness on scintillation characteristics of columnar CsI:Tl films exposed to high gamma radiation doses

    NASA Astrophysics Data System (ADS)

    Shinde, Seema; Singh, S. G.; Sen, S.; Gadkari, S. C.

    2016-02-01

    Oriented columnar films of Tl doped CsI (CsI:Tl) of varying thicknesses from 50 μm to 1000 μm have been deposited on silica glass substrates by a thermal evaporation technique. The SEM micrographs confirmed the columnar structure of the film while the powder X-ray diffraction pattern recorded for the films revealed a preferred orientation of the grown columns along the <200> direction. Effects of high energy gamma exposure up to 1000 Gy on luminescence properties of the films were investigated. Results of radio-luminescence, photo-luminescence and scintillation studies on the films are compared with those of a CsI:Tl single crystal with similar thickness. A possible correlation between the film thicknesses and radiation damage in films has been observed.

  19. Comparison of the columnar-thin-film and vacuum-metal-deposition techniques to develop sebaceous fingermarks on nonporous substrates.

    PubMed

    Williams, Stephanie F; Pulsifer, Drew P; Shaler, Robert C; Ramotowski, Robert S; Brazelle, Shelly; Lakhtakia, Akhlesh

    2015-03-01

    Both the columnar-thin-film (CTF) and the vacuum-metal-deposition (VMD) techniques for visualizing sebaceous fingermarks require the deposition of a material thereon in a vacuum chamber. Despite that similarity, there are many differences between the two techniques. The film deposited with the CTF technique has a columnar morphology, but the film deposited with the VMD technique comprises discrete islands. A split-print methodology on a variety of fingermarked substrates was used to determine that the CTF technique is superior for developing fingermarks on clear sandwich bags and partial bloody fingermarks on stainless steel. Both techniques are similar in their ability to develop fingermarks on glass but the CTF technique yields higher contrast. The VMD technique is superior for developing fingermarks on white grocery bags and the smooth side of Gloss Finish Scotch Multitask(™) tape. Neither technique worked well for fingermarks on black garbage bags. PMID:25421147

  20. H-Bonded Donor-Acceptor Units Segregated in Coaxial Columnar Assemblies: Toward High Mobility Ambipolar Organic Semiconductors.

    PubMed

    Feringán, Beatriz; Romero, Pilar; Serrano, José Luis; Folcia, César L; Etxebarria, Jesús; Ortega, Josu; Termine, Roberto; Golemme, Attilio; Giménez, Raquel; Sierra, Teresa

    2016-09-28

    A novel approach to ambipolar semiconductors based on hydrogen-bonded complexes between a star-shaped tris(triazolyl)triazine and triphenylene-containing benzoic acids is described. The formation of 1:3 supramolecular complexes was evidenced by different techniques. Mesogenic driving forces played a decisive role in the formation of the hydrogen-bonded complexes in the bulk. All of the complexes formed by nonmesogenic components gave rise to hexagonal columnar (Colh) liquid crystal phases, which are stable at room temperature. In all cases, X-ray diffraction experiments supported by electron density distribution maps confirmed triphenylene/tris(triazolyl)triazine segregation into hexagonal sublattices and lattices, respectively, as well as remarkable intracolumnar order. These highly ordered nanostructures, obtained by the combined supramolecular H-bond/columnar liquid crystal approach, yielded donor/acceptor coaxial organization that is promising for the formation of ambipolar organic semiconductors with high mobilities, as indicated by charge transport measurements. PMID:27577722