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Sample records for orb web sticky

  1. Optics of Spider Sticky Orb Webs

    DTIC Science & Technology

    2011-01-01

    silks of Australian orb web weaving spiders . Studies of both 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 06-10-2011 13. SUPPLEMENTARY NOTES The...thin film effects as the primary causes. We report systematic studies carried out using the silks of Australian orb web weaving spiders . Studies of... spiders . Studies of both white light and laser light scattering/propagation by natural spider silks have definitively determined the primary cause

  2. Optics of spider "sticky" orb webs

    NASA Astrophysics Data System (ADS)

    Kane, Deb M.; Staib, Gregory R.; Naidoo, Nishen; Little, Douglas J.; Herberstein, Marie E.

    2011-04-01

    Spider orb webs are known to produce colour displays in nature, both in reflection and transmission of sunlight, under certain illumination conditions. The cause of these colours has been the subject of speculation since the time of Newton. It has also been the topic of observational interpretation and some experiment which has proposed diffraction by the fine silks, scattering from rough/structured surfaces and thin film effects as the primary causes. We report systematic studies carried out using the silks of Australian orb web weaving spiders. Studies of both white light and laser light scattering/propagation by natural spider silks have definitively determined the primary cause of the colour displays is rainbows that can be understood by the application of geometric optics combined with new knowledge of the optical properties of the spider web strands, silks, and proteins as optical materials. Additionally, a range of microscopies (optical, AFM, optical surface profiling) show the silks to be optically flat. Overall, spider silks emerge as fascinating optical materials with high dispersion, high birefringence and the potential for future research to show they have high nonlinear optical coefficients. Their importance as a bioinspiration in optics is only just beginning to be realised. Their special optical properties have been achieved by ~136 million years of evolution driven by the need for the web to evade detection by insect prey.

  3. The mechanical properties of the non-sticky spiral in Nephila orb webs (Araneae, Nephilidae).

    PubMed

    Hesselberg, Thomas; Vollrath, Fritz

    2012-10-01

    Detailed information on web geometry and the material properties of the various silks used enables the function of the web's different structures to be elucidated. In this study we investigated the non-sticky spiral in Nephila edulis webs, which in this species is not removed during web building. This permanent non-sticky spiral shows several modifications compared with others, e.g. temporary non-sticky spirals - it is zigzag shaped and wrapped around the radial thread at the elongated junctions. The material properties of the silk used in the non-sticky spiral and other scaffolding structures (i.e. radii, frame and anchor threads) were comparable. However, the fibre diameters differed, with the non-sticky spiral threads being significantly smaller. We used the measured data in a finite element (FE) model of the non-sticky spiral in a segment of the web. The FE analysis suggested that the observed zigzag index resulted from the application of very high pre-stresses to the outer turns of the non-sticky spiral. However, final pre-stress levels in the non-sticky spiral after reorganisation were down to 300 MPa or 1.5-2 times the stress in the radii, which is probably closer to the stress applied by the spider during web building.

  4. On the Colours of Spider Orb-Webs

    ERIC Educational Resources Information Center

    Suhr, Wilfried; Schlichting, H. Joachim

    2011-01-01

    A sticky capture thread from the spiral element of spider orb-webs is formed of almost regularly spaced droplets that surround a supporting axial fibre. From the perspective of physical optics it represents a periodic linear array of scattering elements that acts as a diffraction grating. This is a novel aspect, which is of vital importance for…

  5. On the colours of spider orb-webs

    NASA Astrophysics Data System (ADS)

    Suhr, Wilfried; Schlichting, H. Joachim

    2011-03-01

    A sticky capture thread from the spiral element of spider orb-webs is formed of almost regularly spaced droplets that surround a supporting axial fibre. From the perspective of physical optics it represents a periodic linear array of scattering elements that acts as a diffraction grating. This is a novel aspect, which is of vital importance for the understanding of the overall scattering pattern. To demonstrate its significance, we present our experimental findings and compare them with results of a simplified model.

  6. Behavioural and biomaterial coevolution in spider orb webs.

    PubMed

    Sensenig, A; Agnarsson, I; Blackledge, T A

    2010-09-01

    Mechanical performance of biological structures, such as tendons, byssal threads, muscles, and spider webs, is determined by a complex interplay between material quality (intrinsic material properties, larger scale morphology) and proximate behaviour. Spider orb webs are a system in which fibrous biomaterials--silks--are arranged in a complex design resulting from stereotypical behavioural patterns, to produce effective energy absorbing traps for flying prey. Orb webs show an impressive range of designs, some effective at capturing tiny insects such as midges, others that can occasionally stop even small birds. Here, we test whether material quality and behaviour (web design) co-evolve to fine-tune web function. We quantify the intrinsic material properties of the sticky capture silk and radial support threads, as well as their architectural arrangement in webs, across diverse species of orb-weaving spiders to estimate the maximum potential performance of orb webs as energy absorbing traps. We find a dominant pattern of material and behavioural coevolution where evolutionary shifts to larger body sizes, a common result of fecundity selection in spiders, is repeatedly accompanied by improved web performance because of changes in both silk material and web spinning behaviours. Large spiders produce silk with improved material properties, and also use more silk, to make webs with superior stopping potential. After controlling for spider size, spiders spinning higher quality silk used it more sparsely in webs. This implies that improvements in silk quality enable 'sparser' architectural designs, or alternatively that spiders spinning lower quality silk compensate architecturally for the inferior material quality of their silk. In summary, spider silk material properties are fine-tuned to the architectures of webs across millions of years of diversification, a coevolutionary pattern not yet clearly demonstrated for other important biomaterials such as tendon, mollusc

  7. Wind induces variations in spider web geometry and sticky spiral droplet volume.

    PubMed

    Wu, Chao-Chia; Blamires, Sean J; Wu, Chung-Lin; Tso, I-Min

    2013-09-01

    Trap building by animals is rare because it comes at a substantial cost. Using materials with properties that vary across environments maintains trap functionality. The sticky spiral silks of spider orb webs are used to catch flying prey. Web geometry, accompanied by compensatory changes in silk properties, may change across environments to sustain web functionality. We exposed the spider Cyclosa mulmeinensis to wind to test whether wind-induced changes in web geometry are accompanied by changes in aggregate silk droplet morphology, axial thread width or spiral stickiness. We compared: (i) web catching area, (ii) length of total silks, (iii) mesh height, (iv) number of radii, (v) aggregate droplet morphology and (vi) spiral thread stickiness, between webs made by spiders exposed to wind and those made by spiders not exposed to wind. We interpreted co-variation in droplet morphology or spiral stickiness with web capture area, mesh height or spiral length as the silk properties functionally compensating for changes in web geometry to reduce wind drag. Wind-exposed C. mulmeinensis built webs with smaller capture areas, shorter capture spiral lengths and more widely spaced capture spirals, resulting in the expenditure of less silk. Individuals that were exposed to wind also deposited larger droplets of sticky silk but the stickiness of the spiral threads remained unchanged. The larger droplets may be a product of a greater investment in water, or low molecular weight compounds facilitating atmospheric water uptake. Either way, droplet dehydration in wind is likely to be minimized.

  8. Radius construction and structure in the orb-web of Zilla diodia (Araneidae).

    PubMed

    Zschokke, S

    2000-10-01

    In orb-webs, the tension of the sticky spiral produces a centripetal force on the radii, resulting in an increase in tension along each radius from the centre of the web to the periphery. Zilla diodia (Walckenaer, 1802) atypical of araneids, was found to adapt the structure of its radii to this tension gradient by building radii that are double stranded at the periphery of the web and single stranded near the centre. Furthermore, the proportion of each radius that is doubled was found to be larger in the upper part of the web - where the overall tensions in the radii are known to be higher than in the lower part of the web. suggesting that the spider adjusts the proportion of each radius that is doubled to the overall tension in the radius.

  9. Spider orientation and hub position in orb webs

    NASA Astrophysics Data System (ADS)

    Zschokke, Samuel; Nakata, Kensuke

    2010-01-01

    Orb-web building spiders (Araneae: Araneoidea, Uloboridae) can be considered as territorial central place foragers. In territorial central place foragers, the optimal foraging arena is circular, with the forager sitting in its centre. In orb webs, the spider’s orientation (head up or head down) whilst waiting for prey on the hub of its web and the downwards-upwards asymmetry of its running speeds are the probable causes for the observed deviation of the hub from the web’s centre. Here, we present an analytical model and a more refined simulation model to analyse the relationships amongst the spider’s running speeds, its orientation whilst waiting for prey and the vertical asymmetry of orb webs. The results of our models suggest that (a) waiting for prey head down is generally favourable because it allows the spider to reach the prey in its web on average quicker than spiders waiting head up, (b) the downwards-upwards running speed asymmetry, together with the head-down orientation of most spiders, are likely causes for the observed vertical asymmetry of orb webs, (c) waiting head up can be advantageous for spiders whose downwards-upwards running speed asymmetry is small and who experience high prey tumbling rates and (d) spiders waiting head up should place their hub lower than similar spiders waiting head down.

  10. Adjustment of web-building initiation to high humidity: a constraint by humidity-dependent thread stickiness in the spider Cyrtarachne.

    PubMed

    Baba, Yuki G; Kusahara, Miki; Maezono, Yasunori; Miyashita, Tadashi

    2014-07-01

    Cyrtarachne is an orb-weaving spider belonging to the subfamily Cyrtarachninae (Araneidae) which includes triangular-web-building Pasilobus and bolas spiders. The Cyrtarachninae is a group of spiders specialized in catching moths, which is thought to have evolved from ordinary orb-weaving araneids. Although the web-building time of nocturnal spiders is in general related to the time of sunset, anecdotal evidence has suggested variability of web-building time in Cyrtarachne and its closely related genera. This study has examined the effects of temperature, humidity, moonlight intensity, and prey (moths) availability on web-building time of Cyrtarachne bufo, Cyrtarachne akirai, and Cyrtarachne nagasakiensis. Generalized linear mixed model (GLMM) have revealed that humidity, and not prey availability, was the essential variable that explained the daily variability of web-building time. Experiments measuring thread stickiness under different humidities showed that, although the thread of Cyrtarachne was found to have strong stickiness under high humidity, low humidity caused a marked decrease of thread stickiness. By contrast, no obvious change in stickiness was seen in an ordinary orb-weaving spider, Larinia argiopiformis. These findings suggest that Cyrtarachne adjusts its web-building time to favorable conditions of high humidity maintaining strong stickiness, which enables the threads to work efficiently for capturing prey.

  11. Adjustment of web-building initiation to high humidity: a constraint by humidity-dependent thread stickiness in the spider Cyrtarachne

    NASA Astrophysics Data System (ADS)

    Baba, Yuki G.; Kusahara, Miki; Maezono, Yasunori; Miyashita, Tadashi

    2014-07-01

    Cyrtarachne is an orb-weaving spider belonging to the subfamily Cyrtarachninae (Araneidae) which includes triangular-web-building Pasilobus and bolas spiders. The Cyrtarachninae is a group of spiders specialized in catching moths, which is thought to have evolved from ordinary orb-weaving araneids. Although the web-building time of nocturnal spiders is in general related to the time of sunset, anecdotal evidence has suggested variability of web-building time in Cyrtarachne and its closely related genera. This study has examined the effects of temperature, humidity, moonlight intensity, and prey (moths) availability on web-building time of Cyrtarachne bufo, Cyrtarachne akirai, and Cyrtarachne nagasakiensis. Generalized linear mixed model (GLMM) have revealed that humidity, and not prey availability, was the essential variable that explained the daily variability of web-building time. Experiments measuring thread stickiness under different humidities showed that, although the thread of Cyrtarachne was found to have strong stickiness under high humidity, low humidity caused a marked decrease of thread stickiness. By contrast, no obvious change in stickiness was seen in an ordinary orb-weaving spider, Larinia argiopiformis. These findings suggest that Cyrtarachne adjusts its web-building time to favorable conditions of high humidity maintaining strong stickiness, which enables the threads to work efficiently for capturing prey.

  12. Does ontogenetic change in orb web asymmetry reflect biogenetic law?

    NASA Astrophysics Data System (ADS)

    Nakata, Kensuke

    2010-11-01

    Most orb web spiders face downward on the web hub, and their webs are vertically asymmetrical, that is, the lower part of the web is larger than the upper part and the ratio of the lower part to the whole web area increases as the spider grows. This phenomenon may reflect biogenetic law such that young animals exhibit a general ancestral trait whereas adults exhibit specific and derived traits. An alternative explanation is that vertical asymmetry may arise from the difference in time required by spiders to move up or down the web to capture prey. The present study tested these two hypotheses for Eriophora sagana. Subadults of this species build their webs with reverse asymmetry in that the upper part of the web area is larger than the lower part. In both subadults and adults, the upper proportion decreased with spider weight, and adult spiders built more symmetric webs. These results support the capture time difference hypothesis.

  13. Optimal foraging, not biogenetic law, predicts spider orb web allometry

    NASA Astrophysics Data System (ADS)

    Gregorič, Matjaž; Kiesbüy, Heine C.; Quiñones Lebrón, Shakira G.; Rozman, Alenka; Agnarsson, Ingi; Kuntner, Matjaž

    2013-03-01

    The biogenetic law posits that the ontogeny of an organism recapitulates the pattern of evolutionary changes. Morphological evidence has offered some support for, but also considerable evidence against, the hypothesis. However, biogenetic law in behavior remains underexplored. As physical manifestation of behavior, spider webs offer an interesting model for the study of ontogenetic behavioral changes. In orb-weaving spiders, web symmetry often gets distorted through ontogeny, and these changes have been interpreted to reflect the biogenetic law. Here, we test the biogenetic law hypothesis against the alternative, the optimal foraging hypothesis, by studying the allometry in Leucauge venusta orb webs. These webs range in inclination from vertical through tilted to horizontal; biogenetic law predicts that allometry relates to ontogenetic stage, whereas optimal foraging predicts that allometry relates to gravity. Specifically, pronounced asymmetry should only be seen in vertical webs under optimal foraging theory. We show that, through ontogeny, vertical webs in L. venusta become more asymmetrical in contrast to tilted and horizontal webs. Biogenetic law thus cannot explain L. venusta web allometry, but our results instead support optimization of foraging area in response to spider size.

  14. Optimal foraging, not biogenetic law, predicts spider orb web allometry.

    PubMed

    Gregorič, Matjaž; Kiesbüy, Heine C; Lebrón, Shakira G Quiñones; Rozman, Alenka; Agnarsson, Ingi; Kuntner, Matjaž

    2013-03-01

    The biogenetic law posits that the ontogeny of an organism recapitulates the pattern of evolutionary changes. Morphological evidence has offered some support for, but also considerable evidence against, the hypothesis. However, biogenetic law in behavior remains underexplored. As physical manifestation of behavior, spider webs offer an interesting model for the study of ontogenetic behavioral changes. In orb-weaving spiders, web symmetry often gets distorted through ontogeny, and these changes have been interpreted to reflect the biogenetic law. Here, we test the biogenetic law hypothesis against the alternative, the optimal foraging hypothesis, by studying the allometry in Leucauge venusta orb webs. These webs range in inclination from vertical through tilted to horizontal; biogenetic law predicts that allometry relates to ontogenetic stage, whereas optimal foraging predicts that allometry relates to gravity. Specifically, pronounced asymmetry should only be seen in vertical webs under optimal foraging theory. We show that, through ontogeny, vertical webs in L. venusta become more asymmetrical in contrast to tilted and horizontal webs. Biogenetic law thus cannot explain L. venusta web allometry, but our results instead support optimization of foraging area in response to spider size.

  15. Food caching in orb-web spiders (Araneae: Araneoidea)

    NASA Astrophysics Data System (ADS)

    Champion de Crespigny, Fleur E.; Herberstein, Marie E.; Elgar, Mark A.

    2001-01-01

    Caching or storing surplus prey may reduce the risk of starvation during periods of food deprivation. While this behaviour occurs in a variety of birds and mammals, it is infrequent among invertebrates. However, golden orb-web spiders, Nephila edulis, incorporate a prey cache in their relatively permanent web, which they feed on during periods of food shortage. Heavier spiders significantly reduced weight loss if they were able to access a cache, but lost weight if the cache was removed. The presence or absence of stored prey had no effect on the weight loss of lighter spiders. Furthermore, N. edulis always attacked new prey, irrespective of the number of unprocessed prey in the web. In contrast, females of Argiope keyserlingi, who build a new web every day and do not cache prey, attacked fewer new prey items if some had already been caught. Thus, a necessary pre-adaptation to the evolution of prey caching in orb-web spiders may be a durable or permanent web, such as that constructed by Nephila.

  16. Biomaterial evolution parallels behavioral innovation in the origin of orb-like spider webs

    NASA Astrophysics Data System (ADS)

    Blackledge, Todd A.; Kuntner, Matjaž; Marhabaie, Mohammad; Leeper, Thomas C.; Agnarsson, Ingi

    2012-11-01

    Correlated evolution of traits can act synergistically to facilitate organism function. But, what happens when constraints exist on the evolvability of some traits, but not others? The orb web was a key innovation in the origin of >12,000 species of spiders. Orb evolution hinged upon the origin of novel spinning behaviors and innovations in silk material properties. In particular, a new major ampullate spidroin protein (MaSp2) increased silk extensibility and toughness, playing a critical role in how orb webs stop flying insects. Here, we show convergence between pseudo-orb-weaving Fecenia and true orb spiders. As in the origin of true orbs, Fecenia dragline silk improved significantly compared to relatives. But, Fecenia silk lacks the high compliance and extensibility found in true orb spiders, likely due in part to the absence of MaSp2. Our results suggest how constraints limit convergent evolution and provide insight into the evolution of nature's toughest fibers.

  17. Consequences of electrical conductivity in an orb spider's capture web

    NASA Astrophysics Data System (ADS)

    Vollrath, Fritz; Edmonds, Donald

    2013-12-01

    The glue-coated and wet capture spiral of the orb web of the garden cross spider Araneus diadematus is suspended between the dry silk radial and web frame threads. Here, we experimentally demonstrate that the capture spiral is electrically conductive because of necks of liquid connecting the droplets even if the thread is stretched. We examine how this conductivity of the capture spiral may lead to entrapment of charged airborne particles such as pollen, spray droplets and even insects. We further describe and model how the conducting spiral will also locally distort the Earth's ambient electric field. Finally, we examine the hypothesis that such distortion could be used by potential prey to detect the presence of a web but conclude that any effect would probably be too small to allow an insect to take evasive action.

  18. Sexual behavior, cannibalism, and mating plugs as sticky traps in the orb weaver spider Leucauge argyra (Tetragnathidae).

    PubMed

    Aisenberg, Anita; Barrantes, Gilbert

    2011-07-01

    Unpublished field observations in Leucauge argyra, a tropical orb weaver spider, suggest the occurrence of conspicuous mating plugs that could reduce or prevent remating attempts. Otherwise, the sexual behavior of this species remains unknown. The aims of this study were to describe the courtship behavior and copulation in L. argyra and investigate mating plug formation in this species. Fourteen virgin females and 12 plugged females were exposed to up to three males and checked for mating plug formation. Of the 12 virgins that copulated, nine produced plugs (five immediately after copulation), and the five plugged females that copulated produced another mating plug immediately after copulation. We did not detect the transfer of any male substance during copulation but observed a whitish liquid emerging from female genital ducts. Plug formation was positively associated with male twanging during courtship. One virgin and four plugged females cannibalized males. In seven trials with virgins and in three trials with plugged females, the male's palp adhered to a substance that emerged from female genital ducts and spread on her genital plate. The male had to struggle energetically to free his glued palp; two of these males were cannibalized while trying to release their palps. Females seem to determine copulation duration by altering the timing of mating plug formation and through sexual cannibalism. This is the first case reported of a mating plug as a sticky trap for males.

  19. Reverse positional orientation in a neotropical orb-web spider, Verrucosa arenata.

    PubMed

    Rao, Dinesh; Ceballos Fernandez, Oscar; Castañeda-Barbosa, Ernesto; Díaz-Fleischer, Francisco

    2011-08-01

    Most orb-web spiders face downwards in the web. A downward orientation has been proposed to be the optimal strategy because spiders run faster downwards and thus can catch prey quicker. Consequently, orb-web spiders also extend their web in the lower part, leading to top-down web asymmetry. Since the majority of orb-web spiders face downwards, it has been difficult to test the effect of orientation on prey capture and web asymmetry. In this study, we explored the influence of reverse orientation on foraging efficiency and web asymmetry in Verrucosa arenata, a neotropical orb-web spider that faces upwards in the web. We show that reverse orientation does not imply reverse web asymmetry in this species. V. arenata spiders captured more prey in the lower part of the web but more prey per area on the upper part. The average running speeds of spiders did not differ between upward and downward running, but heavier spiders took longer to capture prey while running upwards. We discuss these findings in the context of foraging efficiency and web asymmetry.

  20. Reverse positional orientation in a neotropical orb-web spider, Verrucosa arenata

    NASA Astrophysics Data System (ADS)

    Rao, Dinesh; Fernandez, Oscar Ceballos; Castañeda-Barbosa, Ernesto; Díaz-Fleischer, Francisco

    2011-08-01

    Most orb-web spiders face downwards in the web. A downward orientation has been proposed to be the optimal strategy because spiders run faster downwards and thus can catch prey quicker. Consequently, orb-web spiders also extend their web in the lower part, leading to top-down web asymmetry. Since the majority of orb-web spiders face downwards, it has been difficult to test the effect of orientation on prey capture and web asymmetry. In this study, we explored the influence of reverse orientation on foraging efficiency and web asymmetry in Verrucosa arenata, a neotropical orb-web spider that faces upwards in the web. We show that reverse orientation does not imply reverse web asymmetry in this species. V. arenata spiders captured more prey in the lower part of the web but more prey per area on the upper part. The average running speeds of spiders did not differ between upward and downward running, but heavier spiders took longer to capture prey while running upwards. We discuss these findings in the context of foraging efficiency and web asymmetry.

  1. Mechanical performance of spider orb webs is tuned for high-speed prey.

    PubMed

    Sensenig, Andrew T; Kelly, Sean P; Lorentz, Kimberly A; Lesher, Brittany; Blackledge, Todd A

    2013-09-15

    Spiders in the Orbiculariae spin orb webs that dissipate the mechanical energy of their flying prey, bringing the insects to rest and retaining them long enough for the spider to attack and subdue their meals. Small prey are easily stopped by webs but provide little energetic gain. While larger prey offer substantial nourishment, they are also challenging to capture and can damage the web if they escape. We therefore hypothesized that spider orb webs exhibit properties that improve their probability of stopping larger insects while minimizing damage when the mechanical energy of those prey exceeds the web's capacity. Large insects are typically both heavier and faster flying than smaller prey, but speed plays a disproportionate role in determining total kinetic energy, so we predicted that orb webs may dissipate energy more effectively under faster impacts, independent of kinetic energy per se. We used high-speed video to visualize the impact of wooden pellets fired into orb webs to simulate prey strikes and tested how capture probability varied as a function of pellet size and speed. Capture probability was virtually nil above speeds of ~3 m s(-1). However, successful captures do not directly measure the maximum possible energy dissipation by orb webs because these events include lower-energy impacts that may not significantly challenge orb web performance. Therefore, we also compared the total kinetic energy removed from projectiles that escaped orb webs by breaking through the silk, asking whether more energy was removed at faster speeds. Over a range of speeds relevant to insect flight, the amount of energy absorbed by orb webs increases with the speed of prey (i.e. the rates at which webs are stretched). Orb webs therefore respond to faster - and hence higher kinetic energy - prey with better performance, suggesting adaptation to capture larger and faster flying insect prey. This speed-dependent toughness of a complex structure suggests the utility of the

  2. Wet webs work better: humidity, supercontraction and the performance of spider orb webs.

    PubMed

    Boutry, Cecilia; Blackledge, Todd A

    2013-10-01

    Like many biomaterials, spider silk responds to water through softening and swelling. Major ampullate silk, the main structural element of most prey capture webs, also shrinks dramatically if unrestrained or develops high tension if restrained, a phenomenon called 'supercontraction'. While supercontraction has been investigated for over 30 years, its consequences for web performance remain controversial. Here, we measured prey capture performance of dry and wet (supercontracted) orb webs of Argiope and Nephila using small wood blocks as prey. Prey capture performance significantly increased at high humidity for Argiope while the improvement was less dramatic for Nephila. This difference is likely due to Argiope silk supercontracting more than Nephila silk. Web deflection, measured as the extension of the web upon prey impact, also increased at high humidity in Argiope, suggesting that silk softening upon supercontraction explains the improved performance of wet webs. These results strongly argue that supercontraction is not detrimental to web performance.

  3. Prey interception drives web invasion and spider size determines successful web takeover in nocturnal orb-web spiders.

    PubMed

    Gan, Wenjin; Liu, Shengjie; Yang, Xiaodong; Li, Daiqin; Lei, Chaoliang

    2015-09-24

    A striking feature of web-building spiders is the use of silk to make webs, mainly for prey capture. However, building a web is energetically expensive and increases the risk of predation. To reduce such costs and still have access to abundant prey, some web-building spiders have evolved web invasion behaviour. In general, no consistent patterns of web invasion have emerged and the factors determining web invasion remain largely unexplored. Here we report web invasion among conspecifics in seven nocturnal species of orb-web spiders, and examined the factors determining the probability of webs that could be invaded and taken over by conspecifics. About 36% of webs were invaded by conspecifics, and 25% of invaded webs were taken over by the invaders. A web that was built higher and intercepted more prey was more likely to be invaded. Once a web was invaded, the smaller the size of the resident spider, the more likely its web would be taken over by the invader. This study suggests that web invasion, as a possible way of reducing costs, may be widespread in nocturnal orb-web spiders.

  4. Spider orb webs rely on radial threads to absorb prey kinetic energy.

    PubMed

    Sensenig, Andrew T; Lorentz, Kimberly A; Kelly, Sean P; Blackledge, Todd A

    2012-08-07

    The kinetic energy of flying insect prey is a formidable challenge for orb-weaving spiders. These spiders construct two-dimensional, round webs from a combination of stiff, strong radial silk and highly elastic, glue-coated capture spirals. Orb webs must first stop the flight of insect prey and then retain those insects long enough to be subdued by the spiders. Consequently, spider silks rank among the toughest known biomaterials. The large number of silk threads composing a web suggests that aerodynamic dissipation may also play an important role in stopping prey. Here, we quantify energy dissipation in orb webs spun by diverse species of spiders using data derived from high-speed videos of web deformation under prey impact. By integrating video data with material testing of silks, we compare the relative contributions of radial silk, the capture spiral and aerodynamic dissipation. Radial silk dominated energy absorption in all webs, with the potential to account for approximately 100 per cent of the work of stopping prey in larger webs. The most generous estimates for the roles of capture spirals and aerodynamic dissipation show that they rarely contribute more than 30 per cent and 10 per cent of the total work of stopping prey, respectively, and then only for smaller orb webs. The reliance of spider orb webs upon internal energy absorption by radial threads for prey capture suggests that the material properties of the capture spirals are largely unconstrained by the selective pressures of stopping prey and can instead evolve freely in response to alternative functional constraints such as adhering to prey.

  5. An analysis of the orientation of an orb-web spider.

    PubMed

    Maciejewski, Wes

    2010-08-21

    In nature, orb-web spinning spiders are often observed residing on the hub of their web, facing down. An explanation of this phenomenon has only recently appeared in the literature [Zschokke, S., Nakata, K., 2010. Spider orientation and hub position in orb webs. Naturwissenschaften 97, 43-52, doi:10.1007/s00114-009-0609-7], although a similar explanation is implicit in Masters and Moffat [1983. A functional explanation of top-bottom asymmetry in vertical orbwebs. Animal Behaviour 31, 351-391, doi:10.1016/S0003-3472(83)80010-4] and ap Rhisiart and Vollrath [1994. Design features of the orb web of the spider, Araneus diadematus. Behavioural Ecology 5, 280-287]. In the present article a mathematical description of the region a spider can reach in a fixed amount of time, based on the velocity, turning rate, and initial orientation of a spider, is proposed. Maximizing the amount of prey caught on the web in the long term corresponds to maximizing the area of the region. The orientation that maximizes this area is shown to be downwards. The paper concludes with a conjectured explanation for the vertical asymmetry of orb-webs.

  6. Uncovering changes in spider orb-web topology owing to aerodynamic effects.

    PubMed

    Zaera, Ramón; Soler, Alejandro; Teus, Jaime

    2014-09-06

    An orb-weaving spider's likelihood of survival is influenced by its ability to retain prey with minimum damage to its web and at the lowest manufacturing cost. This set of requirements has forced the spider silk to evolve towards extreme strength and ductility to a degree that is rare among materials. Previous studies reveal that the performance of the web upon impact may not be based on the mechanical properties of silk alone, aerodynamic drag could play a role in the dissipation of the prey's energy. Here, we present a thorough analysis of the effect of the aerodynamic drag on wind load and prey impact. The hypothesis considered by previous authors for the evaluation of the drag force per unit length of thread has been revisited according to well-established principles of fluid mechanics, highlighting the functional dependence on thread diameter that was formerly ignored. Theoretical analysis and finite-element simulations permitted us to identify air drag as a relevant factor in reducing deterioration of the orb web, and to reveal how the spider can take greater-and not negligible-advantage of drag dissipation. The study shows the beneficial air drag effects of building smaller and less dense webs under wind load, and larger and denser webs under prey impact loads. In essence, it points out why the aerodynamics need to be considered as an additional driving force in the evolution of silk threads and orb webs.

  7. Uncovering changes in spider orb-web topology owing to aerodynamic effects

    PubMed Central

    Zaera, Ramón; Soler, Alejandro; Teus, Jaime

    2014-01-01

    An orb-weaving spider's likelihood of survival is influenced by its ability to retain prey with minimum damage to its web and at the lowest manufacturing cost. This set of requirements has forced the spider silk to evolve towards extreme strength and ductility to a degree that is rare among materials. Previous studies reveal that the performance of the web upon impact may not be based on the mechanical properties of silk alone, aerodynamic drag could play a role in the dissipation of the prey's energy. Here, we present a thorough analysis of the effect of the aerodynamic drag on wind load and prey impact. The hypothesis considered by previous authors for the evaluation of the drag force per unit length of thread has been revisited according to well-established principles of fluid mechanics, highlighting the functional dependence on thread diameter that was formerly ignored. Theoretical analysis and finite-element simulations permitted us to identify air drag as a relevant factor in reducing deterioration of the orb web, and to reveal how the spider can take greater—and not negligible—advantage of drag dissipation. The study shows the beneficial air drag effects of building smaller and less dense webs under wind load, and larger and denser webs under prey impact loads. In essence, it points out why the aerodynamics need to be considered as an additional driving force in the evolution of silk threads and orb webs. PMID:24966235

  8. Phylogenomics resolves a spider backbone phylogeny and rejects a prevailing paradigm for orb web evolution.

    PubMed

    Bond, Jason E; Garrison, Nicole L; Hamilton, Chris A; Godwin, Rebecca L; Hedin, Marshal; Agnarsson, Ingi

    2014-08-04

    Spiders represent an ancient predatory lineage known for their extraordinary biomaterials, including venoms and silks. These adaptations make spiders key arthropod predators in most terrestrial ecosystems. Despite ecological, biomedical, and biomaterial importance, relationships among major spider lineages remain unresolved or poorly supported. Current working hypotheses for a spider "backbone" phylogeny are largely based on morphological evidence, as most molecular markers currently employed are generally inadequate for resolving deeper-level relationships. We present here a phylogenomic analysis of spiders including taxa representing all major spider lineages. Our robust phylogenetic hypothesis recovers some fundamental and uncontroversial spider clades, but rejects the prevailing paradigm of a monophyletic Orbiculariae, the most diverse lineage, containing orb-weaving spiders. Based on our results, the orb web either evolved much earlier than previously hypothesized and is ancestral for a majority of spiders or else it has multiple independent origins, as hypothesized by precladistic authors. Cribellate deinopoid orb weavers that use mechanically adhesive silk are more closely related to a diverse clade of mostly webless spiders than to the araneoid orb-weaving spiders that use adhesive droplet silks. The fundamental shift in our understanding of spider phylogeny proposed here has broad implications for interpreting the evolution of spiders, their remarkable biomaterials, and a key extended phenotype--the spider web.

  9. Large orb-webs adapted to maximise total biomass not rare, large prey.

    PubMed

    Harmer, Aaron M T; Clausen, Philip D; Wroe, Stephen; Madin, Joshua S

    2015-09-16

    Spider orb-webs are the ultimate anti-ballistic devices, capable of dissipating the relatively massive kinetic energy of flying prey. Increased web size and prey stopping capacity have co-evolved in a number orb-web taxa, but the selective forces driving web size and performance increases are under debate. The rare, large prey hypothesis maintains that the energetic benefits of rare, very large prey are so much greater than the gains from smaller, more common prey that smaller prey are irrelevant for reproduction. Here, we integrate biophysical and ecological data and models to test a major prediction of the rare, large prey hypothesis, that selection should favour webs with increased stopping capacity and that large prey should comprise a significant proportion of prey stopped by a web. We find that larger webs indeed have a greater capacity to stop large prey. However, based on prey ecology, we also find that these large prey make up a tiny fraction of the total biomass (=energy) potentially captured. We conclude that large webs are adapted to stop more total biomass, and that the capacity to stop rare, but very large, prey is an incidental consequence of the longer radial silks that scale with web size.

  10. Wind speed affects prey-catching behaviour in an orb web spider.

    PubMed

    Turner, Joe; Vollrath, Fritz; Hesselberg, Thomas

    2011-12-01

    Wind has previously been shown to influence the location and orientation of spider web sites and also the geometry and material composition of constructed orb webs. We now show that wind also influences components of prey-catching behaviour within the web. A small wind tunnel was used to generate different wind speeds. Araneus diadematus ran more slowly towards entangled Drosophila melanogaster in windy conditions, which took less time to escape the web. This indicates a lower capture probability and a diminished overall predation efficiency for spiders at higher wind speeds. We conclude that spiders' behaviour of taking down their webs as wind speed increases may therefore not be a response only to possible web damage.

  11. Wind speed affects prey-catching behaviour in an orb web spider

    NASA Astrophysics Data System (ADS)

    Turner, Joe; Vollrath, Fritz; Hesselberg, Thomas

    2011-12-01

    Wind has previously been shown to influence the location and orientation of spider web sites and also the geometry and material composition of constructed orb webs. We now show that wind also influences components of prey-catching behaviour within the web. A small wind tunnel was used to generate different wind speeds. Araneus diadematus ran more slowly towards entangled Drosophila melanogaster in windy conditions, which took less time to escape the web. This indicates a lower capture probability and a diminished overall predation efficiency for spiders at higher wind speeds. We conclude that spiders' behaviour of taking down their webs as wind speed increases may therefore not be a response only to possible web damage.

  12. Upside-down spiders build upside-down orb webs: web asymmetry, spider orientation and running speed in Cyclosa.

    PubMed

    Nakata, Kensuke; Zschokke, Samuel

    2010-10-07

    Almost all spiders building vertical orb webs face downwards when sitting on the hubs of their webs, and their webs exhibit an up-down size asymmetry, with the lower part of the capture area being larger than the upper. However, spiders of the genus Cyclosa, which all build vertical orb webs, exhibit inter- and intraspecific variation in orientation. In particular, Cyclosa ginnaga and C. argenteoalba always face upwards, and C. octotuberculata always face downwards, whereas some C. confusa face upwards and others face downwards or even sideways. These spiders provide a unique opportunity to examine why most spiders face downwards and have asymmetrical webs. We found that upward-facing spiders had upside-down webs with larger upper parts, downward-facing spiders had normal webs with larger lower parts and sideways-facing spiders had more symmetrical webs. Downward-facing C. confusa spiders were larger than upward- and sideways-facing individuals. We also found that during prey attacks, downward-facing spiders ran significantly faster downwards than upwards, which was not the case in upward-facing spiders. These results suggest that the spider's orientation at the hub and web asymmetry enhance its foraging efficiency by minimizing the time to reach prey trapped in the web.

  13. Tangled in a sparse spider web: single origin of orb weavers and their spinning work unravelled by denser taxonomic sampling.

    PubMed

    Dimitrov, Dimitar; Lopardo, Lara; Giribet, Gonzalo; Arnedo, Miquel A; Alvarez-Padilla, Fernando; Hormiga, Gustavo

    2012-04-07

    In order to study the tempo and the mode of spider orb web evolution and diversification, we conducted a phylogenetic analysis using six genetic markers along with a comprehensive taxon sample. The present analyses are the first to recover the monophyly of orb-weaving spiders based solely on DNA sequence data and an extensive taxon sample. We present the first dated orb weaver phylogeny. Our results suggest that orb weavers appeared by the Middle Triassic and underwent a rapid diversification during the end of the Triassic and Early Jurassic. By the second half of the Jurassic, most of the extant orb-weaving families and web designs were already present. The processes that may have given origin to this diversification of lineages and web architectures are discussed. A combination of biotic factors, such as key innovations in web design and silk composition, as well as abiotic environmental changes, may have played important roles in the diversification of orb weavers. Our analyses also show that increased taxon sampling density in both ingroups and outgroups greatly improves phylogenetic accuracy even when extensive data are missing. This effect is particularly important when addition of character data improves gene overlap.

  14. Tangled in a sparse spider web: single origin of orb weavers and their spinning work unravelled by denser taxonomic sampling

    PubMed Central

    Dimitrov, Dimitar; Lopardo, Lara; Giribet, Gonzalo; Arnedo, Miquel A.; Álvarez-Padilla, Fernando; Hormiga, Gustavo

    2012-01-01

    In order to study the tempo and the mode of spider orb web evolution and diversification, we conducted a phylogenetic analysis using six genetic markers along with a comprehensive taxon sample. The present analyses are the first to recover the monophyly of orb-weaving spiders based solely on DNA sequence data and an extensive taxon sample. We present the first dated orb weaver phylogeny. Our results suggest that orb weavers appeared by the Middle Triassic and underwent a rapid diversification during the end of the Triassic and Early Jurassic. By the second half of the Jurassic, most of the extant orb-weaving families and web designs were already present. The processes that may have given origin to this diversification of lineages and web architectures are discussed. A combination of biotic factors, such as key innovations in web design and silk composition, as well as abiotic environmental changes, may have played important roles in the diversification of orb weavers. Our analyses also show that increased taxon sampling density in both ingroups and outgroups greatly improves phylogenetic accuracy even when extensive data are missing. This effect is particularly important when addition of character data improves gene overlap. PMID:22048955

  15. Bourgeois behavior and freeloading in the colonial orb web spider Parawixia bistriata (Araneae, Araneidae).

    PubMed

    Wenseleers, Tom; Bacon, Jonathan P; Alves, Denise A; Couvillon, Margaret J; Kärcher, Martin; Nascimento, Fabio S; Nogueira-Neto, Paulo; Ribeiro, Marcia; Robinson, Elva J H; Tofilski, Adam; Ratnieks, Francis L W

    2013-07-01

    Spiders of the tropical American colonial orb weaver Parawixia bistriata form a communal bivouac in daytime. At sunset, they leave the bivouac and construct individual, defended webs within a large, communally built scaffolding of permanent, thick silk lines between trees and bushes. Once spiders started building a web, they repelled other spiders walking on nearby scaffolding with a "bounce" behavior. In nearly all cases (93%), this resulted in the intruder leaving without a fight, akin to the "bourgeois strategy," in which residents win and intruders retreat without escalated contests. However, a few spiders (6.5%) did not build a web due to lack of available space. Webless spiders were less likely to leave when bounced (only 42% left) and instead attempted to "freeload," awaiting the capture of prey items in nearby webs. Our simple model shows that webless spiders should change their strategy from bourgeois to freeloading satellite as potential web sites become increasingly occupied.

  16. The secondary frame in spider orb webs: the detail that makes the difference.

    PubMed

    Soler, Alejandro; Zaera, Ramón

    2016-08-10

    Spider orb webs are multifunctional structures, the main function of which is to dissipate the kinetic energy of the impacting prey, while minimizing structural damage. There is no single explanation for their remarkable strength and ductility. However, it is clear that topology is decisive in the structural performance upon impact, and the arrangement of the different silk threads in the web must also exert an effect. The aim of this study is to show how a slight variation in the geometry markedly affects the prey-capture ability of spider orb webs. The study is focused on the secondary frame, a thread interposed between radial and primary frame strands, the importance of which has not been examined until now. The simulation of the impact performance of webs using different lengths of the secondary frame clarifies its structural role, which has proven to be decisive. Furthermore, the study explains why secondary frame threads of moderate length, as commonly encountered, enable the capture of prey with higher energy without a marked increase in the volume of silk used.

  17. The secondary frame in spider orb webs: the detail that makes the difference

    PubMed Central

    Soler, Alejandro; Zaera, Ramón

    2016-01-01

    Spider orb webs are multifunctional structures, the main function of which is to dissipate the kinetic energy of the impacting prey, while minimizing structural damage. There is no single explanation for their remarkable strength and ductility. However, it is clear that topology is decisive in the structural performance upon impact, and the arrangement of the different silk threads in the web must also exert an effect. The aim of this study is to show how a slight variation in the geometry markedly affects the prey-capture ability of spider orb webs. The study is focused on the secondary frame, a thread interposed between radial and primary frame strands, the importance of which has not been examined until now. The simulation of the impact performance of webs using different lengths of the secondary frame clarifies its structural role, which has proven to be decisive. Furthermore, the study explains why secondary frame threads of moderate length, as commonly encountered, enable the capture of prey with higher energy without a marked increase in the volume of silk used. PMID:27507613

  18. Female genital mutilation and monandry in an orb-web spider.

    PubMed

    Nakata, Kensuke

    2016-02-01

    Monandry, in which a female has only one mating partner during the reproductive period, is established when a female spontaneously refrains from re-mating, or when a partner male interferes with the attempts of a female to mate again. In the latter case, however, females often have countermeasures against males, which may explain why polyandry is ubiquitous. Here, I demonstrate that the genital appendage, or scape, of the female orb-web spider (Cyclosa argenteoalba) is injured after her first mating, possibly by her first male partner. This female genital mutilation (FGM) permanently precludes copulation, and females appear to have no countermeasures. FGM is considered to confer a strong advantage to males in sexual conflicts over the number of female matings, and it may widely occur in spiders.

  19. Quantifying Human Visible Color Variation from High Definition Digital Images of Orb Web Spiders

    PubMed Central

    Ajuria Ibarra, Helena; Rao, Dinesh

    2016-01-01

    Digital processing and analysis of high resolution images of 30 individuals of the orb web spider Verrucosa arenata were performed to extract and quantify human visible colors present on the dorsal abdomen of this species. Color extraction was performed with minimal user intervention using an unsupervised algorithm to determine groups of colors on each individual spider, which was then analyzed in order to quantify and classify the colors obtained, both spatially and using energy and entropy measures of the digital images. Analysis shows that the colors cover a small region of the visible spectrum, are not spatially homogeneously distributed over the patterns and from an entropic point of view, colors that cover a smaller region on the whole pattern carry more information than colors covering a larger region. This study demonstrates the use of processing tools to create automatic systems to extract valuable information from digital images that are precise, efficient and helpful for the understanding of the underlying biology. PMID:27902724

  20. Spatial learning affects thread tension control in orb-web spiders.

    PubMed

    Nakata, Kensuke

    2013-08-23

    Although it is well known that spatial learning can be important in the biology of predators that actively move around in search for food, comparatively little is known about ways in which spatial learning might function in the strategies of sit-and-wait predators. In this study, Cyclosa octotuberculata, an orb-web spider that uses its legs to contract radial threads of its web to increase thread tension, was trained to capture prey in limited web sectors. After training, spiders that had captured prey in horizontal web sectors applied more tension on radial threads connected to horizontal sectors than spiders that had captured prey in vertical sectors. This result suggests that the effect of experience on C. octotuberculata's behaviour is not expressed in the way the trained spider responds to prey-derived stimuli and is instead expressed in behaviour by which the spider anticipates the likely direction from which prey will arrive in the future. This illustrates that learning can be important even when the predator remains in one location during foraging bouts.

  1. The Role of Salts in the Evolution of Modern Orb-Webs.

    NASA Astrophysics Data System (ADS)

    Sahni, Vasav; Miyoshi, Toshikazu; Chen, Kelley; Jain, Dharamdeep; Blamires, Sean J.; Blackledge, Todd A.; Dhinojwala, Ali

    2014-03-01

    The evolution of modern viscid silk webs from ancient cribellate silk webs is associated with a 95% increase in diversity of orb-weaving spiders, and their dominance as predators of flying insects. Yet the transition's mechanistic basis is an evolutionary puzzle. Ancient cribellate silk is a dry adhesive that functions through van der Waals interactions. Viscid threads adhere more effectively than cribellate threads due to high extensibility of their axial silk fibers, and firm adhesion of the viscid glue droplets. The organic and inorganic salts present in viscid glue sequester atmospheric water that plasticizes the axial silk fibers and renders them extensible. Here, we provide direct molecular and macro-scale evidence to show that salts also generate adhesion by directly solvating the glycoproteins, regardless of water content, thus imparting viscoelasticity and enabling the glue droplets to establish good contact. This `dual role' of salts provides a crucial link to the evolutionary transition from cribellate silk to viscid silk. In addition, salts also provide a simple mechanism to adhere even at the extremes of relative humidity, a feat eluding most synthetic adhesives. The work was done when I was at University of Akron.

  2. Mechanical behavior of silk during the evolution of orb-web spinning spiders.

    PubMed

    Elices, Manuel; Plaza, Gustavo R; Arnedo, Miquel A; Pérez-Rigueiro, José; Torres, Fernando G; Guinea, Gustavo V

    2009-07-13

    The development of an accurate and reproducible approach to measuring the tensile behavior of spider silk has allowed characterizing and comparing the range of mechanical properties exhibited by different spider species with unprecedented detail. The comparison of silks spun by spiders belonging to different phylogenetic groups has revealed that evolution locked in many of the important properties of spider silks very early in the history of orb-web weaving spiders, despite the fact that the silk gland system is relatively isolated in physiological terms from the rest of the organism and should thus mutate quickly. The variations observed between species may be grouped in at least two patterns that are shown not to be related to phylogeny. Beyond the relevance of these results for the evolutionary biology of spiders and silks, the conservation of the basic traits observed in the mechanical behavior of spider silks is likely to set a limit to the range of properties that can be expected from artificial fibers bioinspired in natural silks.

  3. Feeding rate may affect dispersal in the orb-web spider Nephila clavata.

    PubMed

    Miyashita, Tadashi

    1992-12-01

    Population parameters of the orb-web spider Nephila clavata were estimated at two sites with different spider densities (for 2 successive years at the high density site and 1 year at the low density site), and the relationship between survival rate and feeding conditions was examined. The rate of decrease of population density was almost constant over time and nearly the same at the two sites. Daily survival rate (sum of the effects of mortality and emigration) was low during August to early September and increased markedly thereafter. Daily immigration rate (number of immigrants/number of residents) was high during August to early September. Since there were strong negative correlations between survival and immigration rates, low survival rate seems to be caused by a high rate of emigration. Strong positive correlations were found between survival rate and feeding frequency (mean percent observed feeding). Analysis of covariance revealed that the parameters of the regression between survival rate and feeding frequency did not differ significantly among three occasions. These results suggest that feeding condition has a significant influence on dispersal activity of populations in this spider.

  4. Old maids have more appeal: effects of age and pheromone source on mate attraction in an orb-web spider

    PubMed Central

    Schneider, Jutta M.

    2016-01-01

    Background. In many insects and spider species, females attract males with volatile sex pheromones, but we know surprisingly little about the costs and benefits of female pheromone emission. Here, we test the hypothesis that mate attraction by females is dynamic and strategic in the sense that investment in mate attraction is matched to the needs of the female. We use the orb-web spider Argiope bruennichi in which females risk the production of unfertilised egg clutches if they do not receive a copulation within a certain time-frame. Methods. We designed field experiments to compare mate attraction by recently matured (young) females with females close to oviposition (old). In addition, we experimentally separated the potential sources of pheromone transmission, namely the female body and the web silk. Results. In accordance with the hypothesis of strategic pheromone production, the probability of mate attraction and the number of males attracted differed between age classes. While the bodies and webs of young females were hardly found by males, the majority of old females attracted up to two males within two hours. Old females not only increased pheromone emission from their bodies but also from their webs. Capture webs alone spun by old females were significantly more efficient in attracting males than webs of younger females. Discussion. Our results suggest that females modulate their investment in signalling according to the risk of remaining unmated and that they thereby economize on the costs associated with pheromone production and emission. PMID:27114864

  5. Old maids have more appeal: effects of age and pheromone source on mate attraction in an orb-web spider.

    PubMed

    Cory, Anna-Lena; Schneider, Jutta M

    2016-01-01

    Background. In many insects and spider species, females attract males with volatile sex pheromones, but we know surprisingly little about the costs and benefits of female pheromone emission. Here, we test the hypothesis that mate attraction by females is dynamic and strategic in the sense that investment in mate attraction is matched to the needs of the female. We use the orb-web spider Argiope bruennichi in which females risk the production of unfertilised egg clutches if they do not receive a copulation within a certain time-frame. Methods. We designed field experiments to compare mate attraction by recently matured (young) females with females close to oviposition (old). In addition, we experimentally separated the potential sources of pheromone transmission, namely the female body and the web silk. Results. In accordance with the hypothesis of strategic pheromone production, the probability of mate attraction and the number of males attracted differed between age classes. While the bodies and webs of young females were hardly found by males, the majority of old females attracted up to two males within two hours. Old females not only increased pheromone emission from their bodies but also from their webs. Capture webs alone spun by old females were significantly more efficient in attracting males than webs of younger females. Discussion. Our results suggest that females modulate their investment in signalling according to the risk of remaining unmated and that they thereby economize on the costs associated with pheromone production and emission.

  6. Mercury bioaccumulation, speciation, and influence on web structure in orb-weaving spiders from a forested watershed.

    PubMed

    Wyman, Katherine E; Rodenhouse, Nicholas L; Bank, Michael S

    2011-08-01

    Atmospheric deposition is an important source of Hg in remote terrestrial ecosystems of northeastern North America. As high-level invertebrate consumers, orb-weaving spiders (family Araneidae) are excellent subjects for studying the impact of sublethal levels of Hg on forest animals because their webs provide snapshots of behavior and neurological function. Spiders of the diadematus group of the genus Araneus were collected from the Jeffers Brook watershed in the White Mountain National Forest, New Hampshire (USA), and analyzed for Hg content. Webs were photographed and measured to test for correlations between Hg body burden and web structure. Collected spiders contained concentrations of total Hg averaging 44.7 ± 10.0 ng/g Hg (wet mass; mean ± standard deviation), with 37 ± 6% of the total Hg present in the methylmercury form. Mercury loads were likely accumulated through diet (potential prey items contained an average of 43% of the Hg load in collected spiders) and possibly web ingestion. The present study found no direct evidence that the web structure-and thus the prey-capture ability-of spiders in the study area was affected by their Hg body burden.

  7. The influence of vibratory courtship on female mating behaviour in orb-web spiders (Argiope keyserlingi, Karsch 1878).

    PubMed

    Wignall, Anne E; Herberstein, Marie E

    2013-01-01

    Web-building spiders are important models for sexual selection. While our understanding of post-copulatory mechanisms including sperm competition and cryptic female choice is considerable, our knowledge of courtship and how it influences male and female mating decisions is still extremely poor. Here, we provide the first comprehensive description of male courtship behaviour and vibrations generated in the web by the orb-web spider, Argiope keyserlingi - a recognised model species. We identified three main elements of male courtship: shudders, abdominal wags and mating thread dances (including both plucks and bounces). The vibrations generated by these behaviours are described in detail. Male shuddering behaviour appears to have a strong influence on female latency to mate acceptance, with males that shudder at high rates without compromising shudder duration being preferred. Shuddering behaviour may also mediate female aggressive behaviour, with males that generate long shudders less likely to be cannibalised after copulation. Male abdominal wagging behaviour, however, appears to have only limited influence on female mating decisions. This study provides avenues for future work that synthesises pre- and post-copulatory mechanisms in web-building spiders to generate an all-encompassing model of how sexual selection operates.

  8. Silken toolkits: biomechanics of silk fibers spun by the orb web spider Argiope argentata (Fabricius 1775).

    PubMed

    Blackledge, Todd A; Hayashi, Cheryl Y

    2006-07-01

    Orb-weaving spiders spin five fibrous silks from differentiated glands that contain unique sets of proteins. Despite diverse ecological functions, the mechanical properties of most of these silks are not well characterized. Here, we quantify the mechanical performance of this toolkit of silks for the silver garden spider Argiope argentata. Four silks exhibit viscoelastic behaviour typical of polymers, but differ statistically from each other by up to 250% in performance, giving each silk a distinctive suite of material properties. Major ampullate silk is 50% stronger than other fibers, but also less extensible. Aciniform silk is almost twice as tough as other silks because of high strength and extensibility. Capture spiral silk, coated with aqueous glue, is an order of magnitude stretchier than other silks. Dynamic mechanical properties are qualitatively similar, but quantitatively vary by up to 300% among silks. Storage moduli are initially nearly constant and increase after fiber yield, whereas loss tangents reach maxima of 0.1-0.2 at the yield. The remarkable mechanical diversity of Argiope argentata silks probably results in part from the different molecular structures of fibers and can be related to the specific ecological role of each silk. Our study indicates substantial potential to customize the mechanics of bioengineered silks.

  9. Analysis of transcriptomes of three orb-web spider species reveals gene profiles involved in silk and toxin.

    PubMed

    Zhao, Ying-Jun; Zeng, Yan; Chen, Lei; Dong, Yang; Wang, Wen

    2014-12-01

    As an ancient arthropod with a history of 390 million years, spiders evolved numerous morphological forms resulting from adaptation to different environments. The venom and silk of spiders, which have promising commercial applications in agriculture, medicine and engineering fields, are of special interests to researchers. However, little is known about their genomic components, which hinders not only understanding spider biology but also utilizing their valuable genes. Here we report on deep sequenced and de novo assembled transcriptomes of three orb-web spider species, Gasteracantha arcuata, Nasoonaria sinensis and Gasteracantha hasselti which are distributed in tropical forests of south China. With Illumina paired-end RNA-seq technology, 54 871, 101 855 and 75 455 unigenes for the three spider species were obtained, respectively, among which 9 300, 10 001 and 10 494 unique genes are annotated, respectively. From these annotated unigenes, we comprehensively analyzed silk and toxin gene components and structures for the three spider species. Our study provides valuable transcriptome data for three spider species which previously lacked any genetic/genomic data. The results have laid the first fundamental genomic basis for exploiting gene resources from these spiders.

  10. Nutrients intake determines the post-maturity molting in the golden orb-web spider Nephila pilipes (Araneae: Nephilidae).

    PubMed

    Cheng, Ren-Chung; Zhang, Shichang; Chen, Yu-Chun; Lee, Chia-Yi; Chou, Yi-Ling; Ye, Hui-Ying; Piorkowski, Dakota; Liao, Chen-Pan; Tso, I-Min

    2017-04-10

    While molting occurs in the development of many animals especially in arthropods, post-maturity molting (PMM, organisms continue to molt after sexual maturity) has received little attention. Mechanism of molting has been studied intensively, however, the mechanism of PMM remains unknown although it is suggested to be crucial for the development of body size. In this study, we investigated factors that potentially induce PMM in the golden orb-web spider Nephila pilipes, which has the greatest degree of sexual dimorphism among terrestrial animals. We manipulated the mating history and the nutrient consumption of the females to examine whether they can affect PMM. The results showed that female spiders under low nutrition were more likely to molt as adults, and mating had no significant influence to the occurrence rate of PMM. Moreover, spiders that experienced PMM lived longer than those without and their body sizes were significantly increased. Therefore, we concluded that it is the nutritional condition rather than the mating history that has affected PMM.

  11. Subunit sequences of the 4 x 6-mer hemocyanin from the golden orb-web spider, Nephila inaurata.

    PubMed

    Averdam, Anne; Markl, Jürgen; Burmester, Thorsten

    2003-08-01

    The transport of oxygen in the hemolymph of many arthropod and mollusc species is mediated by large copper-proteins that are referred to as hemocyanins. Arthropod hemocyanins are composed of hexamers and oligomers of hexamers. Arachnid hemocyanins usually form 4 x 6-mers consisting of seven distinct subunit types (termed a-g), although in some spider taxa deviations from this standard scheme have been observed. Applying immunological and electrophoretic methods, six distinct hemocyanin subunits were identified in the red-legged golden orb-web spider Nephila inaurata madagascariensis (Araneae: Tetragnathidae). The complete cDNA sequences of six subunits were obtained that corresponded to a-, b-, d-, e-, f- and g-type subunits. No evidence for a c-type subunit was found in this species. The inclusion of the N. inaurata hemocyanins in a multiple alignment of the arthropod hemocyanins and the application of the Bayesian method of phylogenetic inference allow, for the first time, a solid reconstruction of the intramolecular evolution of the chelicerate hemocyanin subunits. The branch leading to subunit a diverged first, followed by the common branch of the dimer-forming b and c subunits, while subunits d and f, as well as subunits e and g form common branches. Assuming a clock-like evolution of the chelicerate hemocyanins, a timescale for the evolution of the Chelicerata was obtained that agrees with the fossil record.

  12. The effect of colour polymorphism on thermoregulation in an orb web spider.

    PubMed

    Rao, Dinesh; Mendoza-Cuenca, Luis

    2016-08-01

    Spiders that build aerial webs in open areas face the risk of overheating due to incident solar radiation. These spiders can counteract overheating by either moving the web to another site or by adopting behavioural thermoregulation within the web. Since moving can be costly, studies have suggested that a passive but effective method of reducing heat load is by light reflectance through body colouration. We explored the interaction between colour and thermoregulation in a colour polymorphic species, under both field and laboratory conditions. We show that in natural conditions, the spiders maintain their body temperature below that of the ambient, but with no difference in surface temperature between colour morphs. In laboratory experiments with internal temperature measurements, white morphs bore the risk of overheating better than the yellow morphs since they heated up slower and cooled faster. We suggest that the thermoregulatory properties of colour polymorphism in Verrucosa arenata have physiological consequences and may play an important role in the maintenance of colour polymorphism in this species.

  13. The effect of colour polymorphism on thermoregulation in an orb web spider

    NASA Astrophysics Data System (ADS)

    Rao, Dinesh; Mendoza-Cuenca, Luis

    2016-08-01

    Spiders that build aerial webs in open areas face the risk of overheating due to incident solar radiation. These spiders can counteract overheating by either moving the web to another site or by adopting behavioural thermoregulation within the web. Since moving can be costly, studies have suggested that a passive but effective method of reducing heat load is by light reflectance through body colouration. We explored the interaction between colour and thermoregulation in a colour polymorphic species, under both field and laboratory conditions. We show that in natural conditions, the spiders maintain their body temperature below that of the ambient, but with no difference in surface temperature between colour morphs. In laboratory experiments with internal temperature measurements, white morphs bore the risk of overheating better than the yellow morphs since they heated up slower and cooled faster. We suggest that the thermoregulatory properties of colour polymorphism in Verrucosa arenata have physiological consequences and may play an important role in the maintenance of colour polymorphism in this species.

  14. Systematics, phylogeny, and evolution of orb-weaving spiders.

    PubMed

    Hormiga, Gustavo; Griswold, Charles E

    2014-01-01

    The orb-weaving spiders (Orbiculariae) comprise more than 25% of the approximately 44,000 known living spider species and produce a remarkable variety of webs. The wheel-shaped orb web is primitive to this clade, but most Orbiculariae make webs hardly recognizable as orbs. Orb-weavers date at least to the Jurassic. With no evidence for convergence of the orb web, the monophyly of the two typical orb web taxa, the cribellate Deinopoidea and ecribellate Araneoidea, remains problematic, supported only weakly by molecular studies. The sister group of the Orbiculariae also remains elusive. Despite more than 15 years of phylogenetic scrutiny, a fully resolved cladogram of the Orbiculariae families is not yet possible. More comprehensive taxon sampling, comparative morphology, and new molecular markers are required for a better understanding of orb-weaver evolution.

  15. Spiders avoid sticking to their webs: clever leg movements, branched drip-tip setae, and anti-adhesive surfaces

    NASA Astrophysics Data System (ADS)

    Briceño, R. D.; Eberhard, W. G.

    2012-04-01

    Orb-weaving spiders construct webs with adhesive silk but are not trapped by it. Previous studies have attributed this defense to an oily coating on their legs that protects against adhesion or, more recently, to behavioral avoidance of sticky lines. The old evidence is very weak, however, and the behavioral avoidance explanation is inadequate because orb-weavers push with their hind legs against sticky lines hundreds or thousands of times during construction of each orb and are not trapped. Video analyses of behavior and experimental observations of isolated legs pulling away from contact with sticky lines showed that the spider uses three anti-adhesion traits: dense arrays of branched setae on the legs that reduce the area of contact with adhesive material; careful engagement and withdrawal movements of its legs that minimize contact with the adhesive and that avoid pulling against the line itself; and a chemical coating or surface layer that reduces adhesion.

  16. Dynamic optimization over infinite-time horizon: web-building strategy in an orb-weaving spider as a case study.

    PubMed

    Venner, Samuel; Chadès, Iadine; Bel-Venner, Marie-Claude; Pasquet, Alain; Charpillet, François; Leborgne, Raymond

    2006-08-21

    Dynamic state-dependent models have been widely developed since 1990s for solving questions in evolutionary ecology. Up to now, these models were mainly run over finite-time horizon. However, for many biological questions an infinite-time horizon perspective could be more appropriate, especially when the end of the modeled period is state- rather than time-dependent. Despite this approach is widely used in the field of economics and operational research, thus far no work has been providing biologists with a general method to solve infinite-time horizon problems. Here we present such a method, through the exhaustive description of an algorithm that we implement to determine the strategy an organism should follow to reach a particular state as fast as possible while limiting mortality risk. To illustrate that method we explored web-building behavior in an orb-weaving spider. How are adult females predicted to build their successive webs to gain energy, grow, and lay their first clutch as fast as possible, without suffering from either predation or starvation? From this example, we first show how an optimal strategy over infinite-time horizon can be processed and selected. Second, we analyse variations of the optimal web-building strategy along with the spider's body weight and predation risk during web building. Our model yields two main predictions: (1) spiders reduce their web size as they are gaining weight due to body-mass-dependent cost of web-building behavior, and (2) this reduction in web size starts at lower weight under higher predation risk.

  17. Atomic force microscopy of orb-spider-web-silks to measure surface nanostructuring and evaluate silk fibers per strand

    NASA Astrophysics Data System (ADS)

    Kane, D. M.; Naidoo, N.; Staib, G. R.

    2010-10-01

    Atomic force microscopy (AFM) study is used to measure the surface topology and roughness of radial and capture spider silks on the micro- and nanoscale. This is done for silks of the orb weaver spider Argiope keyserlingi. Capture silk has a surface roughness that is five times less than that for radial silk. The capture silk has an equivalent flatness of λ /100 (5-6 nm deep surface features) as an optical surface. This is equivalent to a very highly polished optical surface. AFM does show the number of silk fibers that make up a silk thread but geometric distortion occurs during sample preparation. This prevented AFM from accurately measuring the silk topology on the microscale in this study.

  18. The great silk alternative: multiple co-evolution of web loss and sticky hairs in spiders.

    PubMed

    Wolff, Jonas O; Nentwig, Wolfgang; Gorb, Stanislav N

    2013-01-01

    Spiders are the most important terrestrial predators among arthropods. Their ecological success is reflected by a high biodiversity and the conquest of nearly every terrestrial habitat. Spiders are closely associated with silk, a material, often seen to be responsible for their great ecological success and gaining high attention in life sciences. However, it is often overlooked that more than half of all Recent spider species have abandoned web building or never developed such an adaptation. These species must have found other, more economic solutions for prey capture and retention, compensating the higher energy costs of increased locomotion activity. Here we show that hairy adhesive pads (scopulae) are closely associated with the convergent evolution of a vagrant life style, resulting in highly diversified lineages of at least, equal importance as the derived web building taxa. Previous studies often highlighted the idea that scopulae have the primary function of assisting locomotion, neglecting the fact that only the distal most pads (claw tufts) are suitable for those purposes. The former observations, that scopulae are used in prey capture, are largely overlooked. Our results suggest the scopulae evolved as a substitute for silk in controlling prey and that the claw tufts are, in most cases, a secondary development. Evolutionary trends towards specialized claw tufts and their composition from a low number of enlarged setae to a dense array of slender ones, as well as the secondary loss of those pads are discussed further. Hypotheses about the origin of the adhesive setae and their diversification throughout evolution are provided.

  19. Sticky Saliva

    NASA Astrophysics Data System (ADS)

    McCarroll, Louise; Solomon, Michael; Schultz, William

    2016-11-01

    Oral and even systemic health begins with healthy saliva by maintaining antibacterial activity, lubricating hard and soft oral tissues, healing, tasting, chewing, and swallowing. Saliva functionality is intimately linked to its rheology. Alterations in saliva rheology may indicate or cause unhealthy biological function. One imprecise pathological designation is "sticky saliva", usually self-reported or qualitatively described by health professionals. Saliva is 99% water and therefore behaves like water in shear. Saliva also contains mucins, electrolytes, enzymes, hormones, and antibodies. These additional constituents enable saliva to form a long-lasting filament with a "beads-on-a-string" morphology in extension. Therefore, the main kinematic feature that distinguishes the coupling between the oral cavity and saliva elongational mechanics. We investigate the effect of pH and salinity on saliva filament formation with preliminary experiments and compare to 1D unsteady viscoelastic models. We discuss the results in the context of saliva functionality and in generating more satisfactory saliva substitutes for those suffering from xerostomia. We will discuss when beads-on-a-string are likely to occur.

  20. Do parasitoids explain differential abundance of two syntopic orb-weaver spiders (Araneae: Araneidae)?

    NASA Astrophysics Data System (ADS)

    Gonzaga, Marcelo O.; Cardoso, João C. F.; Vasconcellos-Neto, João

    2015-11-01

    In this study, we examined the relative abundance of two congeneric species of orb-weaver spiders, Cyclosa fililineata and Cyclosa morretes, in an area of Atlantic forest in southeastern Brazil, and the relationship of this variable with fecundity and attacks by parasitoids. We also investigated responses to vibrational stimuli that simulated the approach of a wasp and described architectural changes in webs of parasitized individuals of C. fililineata. C.fililineata was more abundant throughout the year, although this species produced a lower number of egg sacs and a lower number of eggs per egg sac when compared with C. morretes. Both species showed similar types of behavioral responses to vibrational stimuli, but C. fililineata remained motionless more often. The frequency of parasitism by the wasp Polysphincta janzeni on adults and juveniles was low and similar for C. fililineata and C. morretes in both dry and wet seasons. The parasitoid caused alterations in the web design of C. fililineata similar of those observed in other orb-weavers attacked by ichneumonid wasps. Webs constructed by spiders parasitized by larvae in their last instar had a lower number of radii and sticky spirals were completely absent. An egg parasitoid, Baeus cyclosae, attacked C. morretes more often than C. fililineata, possibly as a consequence of its greater clutch size and/or larger eggs. These results indicate that egg mortality caused by B. cyclosae, but not subadult and adult mortality promoted by P. janzeni, may be an important factor determining the relative abundance of these two Cyclosa species.

  1. Short and long-term effects of three neurotoxic insecticides on biological and behavioural attributes of the orb-web spider Alpaida veniliae (Araneae, Araneidae): implications for IPM programs.

    PubMed

    Benamú, Marco A; Schneider, Marcela I; González, Alda; Sánchez, Norma E

    2013-09-01

    Soybean pest control in Argentina is done just by chemical control using broad-spectrum pesticides. Alpaida veniliae (Araneae, Araneidae) is one of the most abundant spider species of the orb web weaver guild in soybean, and it is considered a very important polyphagous predator, attacking different insects' families. The objective of this study was to determine if neurotoxic insecticides commonly used in soybean crops and a new active ingredient registered in Argentina (spinosad) adversely affected survival, prey consumption, mating behaviour, web building and reproductive capacity of A. veniliae females, under standard laboratory conditions. Spinosad was the most harmful insecticide due to high acute toxicity, even at lower concentrations than those registered for its field use and for its sublethal effects also. Cypermethrin caused several sublethal effects although its acute toxicity on spider was lower than other insecticides. It reduced prey consumption, affected web building, caused abnormalities in eggs sacs and decreased drastically the fecundity and fertility at sublethal concentrations. Endosulfan did not reduce prey consumption but it affected web building, caused abnormalities in eggs sacs and egg masses, and decreased the fecundity and fertility. Spinosad was also the compound with the most drastic effect on web building, it did not reduce prey consumption and fecundity, but fertility was reduced and abnormalities in egg sacs and egg masses were observed. The use of these insecticides in IPM programs according to their potential toxicity on spider communities is discussed.

  2. A Sticky Installation

    ERIC Educational Resources Information Center

    Hughes, Rama

    2012-01-01

    In this article, the author describes an art project--a school-wide sticky-note show. The show was inspired by Giant Robot's annual Post-It Show in Los Angeles. The gallery invites hundreds of artists to doodle, draw, paint, and collage onto sticky notes. The individual sticky notes can be silly, ambitious, conceptual, or beautiful, but the…

  3. Phylogenomic analysis of spiders reveals nonmonophyly of orb weavers.

    PubMed

    Fernández, Rosa; Hormiga, Gustavo; Giribet, Gonzalo

    2014-08-04

    Spiders constitute one of the most successful clades of terrestrial predators. Their extraordinary diversity, paralleled only by some insects and mites, is often attributed to the use of silk, and, in one of the largest lineages, to stereotyped behaviors for building foraging webs of remarkable biomechanical properties. However, our understanding of higher-level spider relationships is poor and is largely based on morphology. Prior molecular efforts have focused on a handful of genes but have provided little resolution to key questions such as the origin of the orb weavers. We apply a next-generation sequencing approach to resolve spider phylogeny, examining the relationships among its major lineages. We further explore possible pitfalls in phylogenomic reconstruction, including missing data, unequal rates of evolution, and others. Analyses of multiple data sets all agree on the basic structure of the spider tree and all reject the long-accepted monophyly of Orbiculariae, by placing the cribellate orb weavers (Deinopoidea) with other groups and not with the ecribellate orb weavers (Araneoidea). These results imply independent origins for the two types of orb webs (cribellate and ecribellate) or a much more ancestral origin of the orb web with subsequent loss in the so-called RTA clade. Either alternative demands a major reevaluation of our current understanding of the spider evolutionary chronicle.

  4. Sticky-Note Murals

    ERIC Educational Resources Information Center

    Sands, Ian

    2011-01-01

    In this article, the author describes a sticky-note mural project that originated from his desire to incorporate contemporary materials into his assignments as well as to inspire collaboration between students. The process takes much more than sticking sticky notes to the wall. It takes critical thinking skills and teamwork to design and complete…

  5. The venomous secrets of the web droplets from the viscid spiral of the orb-weaver spider Nephila clavipes (Araneae, Tetragnatidae).

    PubMed

    Salles, Heliana C; Volsi, Evelyn Cristina F R; Marques, Maurício R; Souza, Bibiana M; dos Santos, Lucilene D; Tormena, Cláudio F; Mendes, Maria A; Palma, Mario S

    2006-07-01

    The capture web of N. clavipes presents viscous droplets, which play important roles in web mechanics and prey capture. By using scanning and transmission electron microscopy, it was demonstrated that the web droplets are constituted of different chemical environments, provided by the existence both of an aqueous and a lipid layer, which, in turn, present a suspension of tenths of vesicles containing polypeptides and/or lipids. GC/EI-MS Analysis of the contents of these vesicles led to the identification of some saturated fatty acids, such as decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, octadecanoic acid, and icosanoic acid, while other components were unsaturated fatty acids, such as (Z)-tetradec-9-enoic acid, (Z)-octadec-9-enoic acid, and (Z)-icosa-11-enoic acid; and polyunsaturated fatty acids like (9Z,12Z)-octadeca-9,12-dienoic acid, (9Z,12Z,15Z)-octadeca-9,12,15-trienoic acid, and (11Z,14Z)-icosa-11,14-dienoic acid. Toxic proteins such as calcium-activated proteinase and metalloproteinase jararhagin-like precursor were also identified by using a proteomic approach, indicating the possible involvement of these enzymes in the pre-digestion of spiders' preys web-captured. Apparently, the mixture of fatty acids are relatively toxic to insects by topical application (LD50 64.3+/-7.6 ng mg(-1) honeybee), while the proteins alone present no topical effect; however, when injected into the prey-insects, these proteins presented a moderate toxicity (LD50 40.3+/-4.8 ng mg(-1) honeybee); the mixture of fatty acids and proteins is very toxic to the preys captured by the web droplets of the viscid spiral of Nephila clavipes when topically applied on them (LD50 14.3+/-1.8 ng mg(-1) honeybee).

  6. Oldest true orb-weaving spider (Araneae: Araneidae)

    PubMed Central

    Penney, David; Ortuño, Vicente M

    2006-01-01

    The aerial orb web woven by spiders of the family Araneidae typifies these organisms to laypersons and scientists alike. Here we describe the oldest fossil species of this family, which is preserved in amber from Álava, Spain and represents the first record of Araneidae from the Lower Cretaceous. The fossils provide direct evidence that all three major orb web weaving families: Araneidae, Tetragnathidae and Uloboridae had evolved by this time, confirming the antiquity of the use of this remarkable structure as a prey capture strategy by spiders. Given the complex and stereotyped movements that all orb weavers use to construct their webs, there is little question regarding their common origin, which must have occurred in the Jurassic or earlier. Thus, various forms of this formidable prey capture mechanism were already in place by the time of the explosive Cretaceous co-radiation of angiosperms and their flying insect pollinators. This permitted a similar co-radiation of spider predators with their flying insect prey, presumably without the need for a ‘catch-up lag phase’ for the spiders. PMID:17148427

  7. FUJIFILM X10 white orbs and DeOrbIt

    NASA Astrophysics Data System (ADS)

    Dietz, Henry Gordon

    2013-01-01

    The FUJIFILM X10 is a high-end enthusiast compact digital camera using an unusual sensor design. Unfortunately, upon its Fall 2011 release, the camera quickly became infamous for the uniquely disturbing "white orbs" that often appeared in areas where the sensor was saturated. FUJIFILM's first attempt at a fix was firmware released on February 25, 2012 if it had little effect. In April 2012, a sensor replacement essentially solved the problem. This paper explores the "white orb" phenomenon in detail. After FUJIFILM's attempt at a firmware fix failed, the author decided to create a post-processing tool that automatically could repair existing images. DeOrbIt was released as a free tool on March 7, 2012. To better understand the problem and how to fix it, the WWW form version of the tool logs images, processing parameters, and evaluations by users. The current paper describes the technical problem, the novel computational photography methods used by DeOrbit to repair affected images, and the public perceptions revealed by this experiment.

  8. Yellow sticky, PHP software for an electronic brainstorming experiment.

    SciTech Connect

    Dornburg, Courtney C.; Stevens, Susan Marie; Davidson, George S.; Forsythe, James Chris

    2007-09-01

    A web-based brainstorm was conducted in the summer of 2007 within the Sandia Restricted Network. This brainstorming experiment was modeled around the 'yellow sticky' brainstorms that are used in many face-to-face meetings at Sandia National Laboratories. This document discusses the implementation and makes suggestions for future implementations.

  9. The sticky platelet syndrome.

    PubMed

    Moncada, Benjamín; Ruíz-Arguelles, Guillermo J; Castillo-Martínez, Claudio

    2013-07-01

    The sticky platelets syndrome (SPS) is a procoagulant condition based on either arterial, venous, or capillary thrombi caused by hyperesponsive and hyperaggregable platelets. This is a frequent disease, which often remains clinically inapparent, until stressful events or combination with other factors increase the risk of developing SPS. The condition is due to a congenital platelet defect with autosomal dominant characteristics, leading to the increased platelet aggregability when they are challenged with epinephrine and adenosine diphosphate. Nowadays classification of this disorder is based on platelet reactivity to both ADP and epinephrine (SPS type 1), epinephrine alone (SPS type 2), and ADP alone (SPS type 3). The diagnoses of the syndrome depend on the functional aggregometer assay. This condition should be taken into account whenever a patient with thrombophilia is considered.

  10. ORBE: Orbital integrator for educational purposes

    NASA Astrophysics Data System (ADS)

    Gallardo, Tabare

    2017-02-01

    ORBE performs numerical integration of an arbitrary planetary system composed by a central star and up to 100 planets and minor bodies. ORBE calculates the orbital evolution of a system of bodies by means of the computation of the time evolution of their orbital elements. It is easy to use and is suitable for educational use by undergraduate students in the classroom as a first approach to orbital integrators.

  11. String and Sticky Tape Experiments.

    ERIC Educational Resources Information Center

    Edge, R. D., Ed.

    1979-01-01

    Explains how to demonstrate the fundamentals of one dimensional kinematics such as Newton's third law of motion, and collision between bodies, using simple materials of marbles, strings, sticky tape, drinking straws, and rubber bands. (GA)

  12. More data, fewer shifts: molecular insights into the evolution of the spinning apparatus in non-orb-weaving spiders.

    PubMed

    Spagna, Joseph C; Gillespie, Rosemary G

    2008-01-01

    All spiders produce silk and use it for various functions throughout their lives, but not all spiders produce the same silks, or use them for the same functions. These functions may include building shelters, protecting eggs, and trapping prey. The "RTA clade" of spiders (grass spiders, jumping-spiders, wolf spiders, hackled-band weavers, etc.) is an extremely diverse group ( approximately 18,000 species, representing nearly half of all described species), with great variation in ecology and morphology, including variation in the cribellum, a specialized silk-producing organ. The loss of the cribellum, a structure that produces fibers contributing stickiness to prey snares and which is invariably associated with a set of accessory structures, has been studied in orb-web-weavers and shown to have been lost once during the evolutionary history of the group, but never regained. Relative to the orb-weavers, evolution of the structure remains less-thoroughly studied in the RTA clade. As the cribellum is one member of a suite of traits, the combined action of which is essential in prey-capture, its loss should have ecological correlates or physiological trade-offs of evolutionary interest. Using molecular data from nuclear genes (ribosomal DNAs 18S and 28S, and protein-coding Histone H3), as well as mitochondrial data (Cytochrome oxidase I) totaling approximately 3400 base pairs, we developed a phylogenetic hypothesis for three-clawed lineages in this group, focusing on families where taxonomy and previous cladistic analyses suggest multiple losses, or possibly loss and secondary gain, of the cribellum. Results of Bayesian and direct-optimization (POY) analyses agree on a well-resolved and robust agelenid clade that includes the putative subfamilies Ageleninae, Tegenariinae, Textricinae and Coelotinae, but excludes the cribellate New Zealand genus Neoramia. Optimizing the pattern of cribellum evolution onto these trees shows that the cribellate state is conserved in

  13. Sequential origin in the high performance properties of orb spider dragline silk

    NASA Astrophysics Data System (ADS)

    Blackledge, Todd A.; Pérez-Rigueiro, José; Plaza, Gustavo R.; Perea, Belén; Navarro, Andrés; Guinea, Gustavo V.; Elices, Manuel

    2012-10-01

    Major ampullate (MA) dragline silk supports spider orb webs, combining strength and extensibility in the toughest biomaterial. MA silk evolved ~376 MYA and identifying how evolutionary changes in proteins influenced silk mechanics is crucial for biomimetics, but is hindered by high spinning plasticity. We use supercontraction to remove that variation and characterize MA silk across the spider phylogeny. We show that mechanical performance is conserved within, but divergent among, major lineages, evolving in correlation with discrete changes in proteins. Early MA silk tensile strength improved rapidly with the origin of GGX amino acid motifs and increased repetitiveness. Tensile strength then maximized in basal entelegyne spiders, ~230 MYA. Toughness subsequently improved through increased extensibility within orb spiders, coupled with the origin of a novel protein (MaSp2). Key changes in MA silk proteins therefore correlate with the sequential evolution high performance orb spider silk and could aid design of biomimetic fibers.

  14. Sequential origin in the high performance properties of orb spider dragline silk

    PubMed Central

    Blackledge, Todd A.; Pérez-Rigueiro, José; Plaza, Gustavo R.; Perea, Belén; Navarro, Andrés; Guinea, Gustavo V.; Elices, Manuel

    2012-01-01

    Major ampullate (MA) dragline silk supports spider orb webs, combining strength and extensibility in the toughest biomaterial. MA silk evolved ~376 MYA and identifying how evolutionary changes in proteins influenced silk mechanics is crucial for biomimetics, but is hindered by high spinning plasticity. We use supercontraction to remove that variation and characterize MA silk across the spider phylogeny. We show that mechanical performance is conserved within, but divergent among, major lineages, evolving in correlation with discrete changes in proteins. Early MA silk tensile strength improved rapidly with the origin of GGX amino acid motifs and increased repetitiveness. Tensile strength then maximized in basal entelegyne spiders, ~230 MYA. Toughness subsequently improved through increased extensibility within orb spiders, coupled with the origin of a novel protein (MaSp2). Key changes in MA silk proteins therefore correlate with the sequential evolution high performance orb spider silk and could aid design of biomimetic fibers. PMID:23110251

  15. Spider webs: Damage control

    NASA Astrophysics Data System (ADS)

    Omenetto, Fiorenzo G.; Kaplan, David L.

    2012-04-01

    A study reveals that spider orb webs fail in a nonlinear fashion, owing to the hierarchical organization of the silk proteins. The discovery may serve as inspiration for engineers for the design of aerial, light-weight, robust architectures.

  16. Previous experience and site tenacity in the orb spider Nephila (Araneae, Araneidae).

    PubMed

    Vollrath, F; Houston, A

    1986-09-01

    The tenacity of the orb spider Nephila clavipes to a web site was studied in the laboratory. No differences were found between the giving-up-times and the site tenacity of spiders reared in the laboratory or those caught in the field, nor between spiders raised under a poor or a richt diet. The animals left sites at random and seemed to ignore experiences gained at previous sites.

  17. Quantity Stickiness versus Stackelberg Leadership

    SciTech Connect

    Ferreira, F. A.

    2008-10-30

    We study the endogenous Stackelberg relations in a dynamic market. We analyze a twice-repeated duopoly where, in the beginning, each firm chooses either a quantity-sticky production mode or a quantity-flexible production mode. The size of the market becomes observable after the first period. In the second period, a firm can adjust its quantity if, and only if, it has adopted the flexible mode. Hence, if one firm chooses the sticky mode whilst the other chooses the flexible mode, then they respectively play the roles of a Stackelberg leader and a Stackelberg follower in the second marketing period. We compute the supply quantities at equilibrium and the corresponding expected profits of the firms. We also analyze the effect of the slope parameter of the demand curve on the expected supply quantities and on the profits.

  18. Federal Contractors and Sticky Costs

    DTIC Science & Technology

    2014-11-05

    NPS-CM-14-188 ACQUISITION RESEARCH PROGRAM SPONSORED REPORT SERIES Federal Contractors and Sticky Costs 5 November 2014 Stephen C. Hansen...average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed...Public Policy - iv - Naval Postgraduate School NPS-CM-14-188 Acquisition Research Program Sponsored Report Series Federal Contractors and

  19. Planets, Stars, and Orbs 2 Volume Set

    NASA Astrophysics Data System (ADS)

    Grant, Edward

    2009-07-01

    Illustrations; Preface; Acknowledgements; Abbreviations; Introduction: scope, sources, and social context; 1. Pierre Duhem, Medieval cosmology and the scope of the present day; 2. The sources of cosmology in the late Middle Ages; 3. The social and institutional matrix of scholastic cosmology; Part I. The Cosmos as a Whole and What, if Anything, Lies Beyond: 4. Is the world eternal, without beginning or end?; 5. The creation of the world; 6. The finitude, shape, and place of the world; 7. The perfection of the world; 8. The possibility of other worlds; 9. Extracosmic void space; Part II. The Celestial Region: 10. The incorruptibility of the celestial region; 11. Celestial perfection; 12. On celestial matter: can it exist in a changeless state?; 13. The mobile celestial orbs: concentrics, eccentrics, and epicycles; 14. Are the heavens composed of hard orbs or a fluid substance?; 15. The immobile orb of the cosmos: the empyrean heaven; 16. Celestial light; 17. The properties and qualities of celestial bodies, and the dimensions of the world; 18. On celestial motions and their causes; 19. The influence of the celestial region on the terrestrial; 20. The earth and its cosmic relations: size, centrality, shape, and immobility; Conclusion: Five centuries of scholastic cosmology; Appendices; Bibliography; Index.

  20. Translational Control of Autophagy by Orb in the Drosophila Germline.

    PubMed

    Rojas-Ríos, Patricia; Chartier, Aymeric; Pierson, Stéphanie; Séverac, Dany; Dantec, Christelle; Busseau, Isabelle; Simonelig, Martine

    2015-12-07

    Drosophila Orb, the homolog of vertebrate CPEB, is a key translational regulator involved in oocyte polarity and maturation through poly(A) tail elongation of specific mRNAs. orb also has an essential function during early oogenesis that has not been addressed at the molecular level. Here, we show that orb prevents cell death during early oogenesis, thus allowing oogenesis to progress. It does so through the repression of autophagy by directly repressing, together with the CCR4 deadenylase, the translation of Autophagy-specific gene 12 (Atg12) mRNA. Autophagy and cell death observed in orb mutant ovaries are reduced by decreasing Atg12 or other Atg mRNA levels. These results reveal a role of Orb in translational repression and identify autophagy as an essential pathway regulated by Orb during early oogenesis. Importantly, they also establish translational regulation as a major mode of control of autophagy, a key process in cell homeostasis in response to environmental cues.

  1. Mass predicts web asymmetry in Nephila spiders

    NASA Astrophysics Data System (ADS)

    Kuntner, Matjaž; Gregorič, Matjaž; Li, Daiqin

    2010-12-01

    The architecture of vertical aerial orb webs may be affected by spider size and gravity or by the available web space, in addition to phylogenetic and/or developmental factors. Vertical orb web asymmetry measured by hub displacement has been shown to increase in bigger and heavier spiders; however, previous studies have mostly focused on adult and subadult spiders or on several size classes with measured size parameters but no mass. Both estimations are suboptimal because (1) adult orb web spiders may not invest heavily in optimal web construction, whereas juveniles do; (2) size class/developmental stage is difficult to estimate in the field and is thus subjective, and (3) mass scales differently to size and is therefore more important in predicting aerial foraging success due to gravity. We studied vertical web asymmetry in a giant orb web spider, Nephila pilipes, across a wide range of size classes/developmental stages and tested the hypothesis that vertical web asymmetry (measured as hub displacement) is affected by gravity. On a sample of 100 webs, we found that hubs were more displaced in heavier and larger juveniles and that spider mass explained vertical web asymmetry better than other measures of spider size (carapace and leg lengths, developmental stage). Quantifying web shape via the ladder index suggested that, unlike in other nephilid taxa, growing Nephila orbs do not become vertically elongated. We conclude that the ontogenetic pattern of progressive vertical web asymmetry in Nephila can be explained by optimal foraging due to gravity, to which the opposing selective force may be high web-building costs in the lower orb. Recent literature finds little support for alternative explanations of ontogenetic orb web allometry such as the size limitation hypothesis and the biogenetic law.

  2. Mass predicts web asymmetry in Nephila spiders.

    PubMed

    Kuntner, Matjaz; Gregoric, Matjaz; Li, Daiqin

    2010-12-01

    The architecture of vertical aerial orb webs may be affected by spider size and gravity or by the available web space, in addition to phylogenetic and/or developmental factors. Vertical orb web asymmetry measured by hub displacement has been shown to increase in bigger and heavier spiders; however, previous studies have mostly focused on adult and subadult spiders or on several size classes with measured size parameters but no mass. Both estimations are suboptimal because (1) adult orb web spiders may not invest heavily in optimal web construction, whereas juveniles do; (2) size class/developmental stage is difficult to estimate in the field and is thus subjective, and (3) mass scales differently to size and is therefore more important in predicting aerial foraging success due to gravity. We studied vertical web asymmetry in a giant orb web spider, Nephila pilipes, across a wide range of size classes/developmental stages and tested the hypothesis that vertical web asymmetry (measured as hub displacement) is affected by gravity. On a sample of 100 webs, we found that hubs were more displaced in heavier and larger juveniles and that spider mass explained vertical web asymmetry better than other measures of spider size (carapace and leg lengths, developmental stage). Quantifying web shape via the ladder index suggested that, unlike in other nephilid taxa, growing Nephila orbs do not become vertically elongated. We conclude that the ontogenetic pattern of progressive vertical web asymmetry in Nephila can be explained by optimal foraging due to gravity, to which the opposing selective force may be high web-building costs in the lower orb. Recent literature finds little support for alternative explanations of ontogenetic orb web allometry such as the size limitation hypothesis and the biogenetic law.

  3. The Effects of Alcohol on Spiders: What Happens to Web Construction after Spiders Consume Alcohol?

    ERIC Educational Resources Information Center

    Cross, Victor E.

    2006-01-01

    In the high school experiment reported in this paper, spiders were provided with 40% ethanol (ETOH) in order to determine the effects of alcohol on the web-spinning ability of orb weaver spiders. It was hypothesized that alcohol would have a deleterious effect on the number of radii, number of cells, and area of cells in the webs of orb weaving…

  4. Government Contractors and Sticky SGA Costs

    DTIC Science & Technology

    2015-05-01

    Government Contractors and Sticky SGA Costs by Stephen C. Hansen Naval Postgraduate School These discussion comments reflect the private...2015 to 00-00-2015 4. TITLE AND SUBTITLE Government Contractors and Sticky SGA Costs 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT... contractors . Let Fseg = 1 if a company is a Federal Focus Firm. l ( SGAit ) L ( Revenueit ) og ’ =a0+a1 og ’ SGAi,t-1 Revenuei,t- 1 ( Revenue· t

  5. Spider silk: Webs measure up

    NASA Astrophysics Data System (ADS)

    Qin, Zhao; Buehler, Markus J.

    2013-03-01

    The complete elastic response of a spider's orb web has been quantified by non-invasive light scattering, revealing important insights into the architecture, natural material use and mechanical properties of the web. This knowledge advances our understanding of the prey-catching process and the role of supercontraction therein.

  6. Loss of legs: is it or not a handicap for an orb-weaving spider?

    NASA Astrophysics Data System (ADS)

    Pasquet, Alain; Anotaux, Mylène; Leborgne, Raymond

    2011-07-01

    Leg loss is a common phenomenon in spiders, and according to the species 5% to 40% of the adults can present at least one missing leg. There is no possibility of regeneration after adult moult and the animal must manage with its missing appendages until its death. With the loss of one or more legs, female orb-weaving spiders can be penalized twice: firstly, because the legs are necessary for web construction and secondly, the legs are essential for the control of the prey after its interception by the web. During development, spiders may be also penalized because regeneration has energetic costs that take away resources for survival, growth and reproduction. All these consequences should influence negatively the development of the spider and thus its fitness. We investigated the impact of leg loss in the orb-weaving spider, Zygiella x-notata by studying its frequency in a natural population and web building and prey capture behaviours in laboratory. In field populations, 9.5% to 13%, of the adult females presented the loss of one or more legs; the majority of individuals had lost only one leg (in 48% of cases, a first one). Leg loss seems to affect all the adult spiders, as there is no difference of mass between intact spiders and those with missing leg. Data obtained with laboratory-reared spiders, showed that the loss of legs due to the moult is rare (less than 1%). Considering changes in web design, spiders with missing legs decreased their silk investment, increased the distance between spiral turns but did not change the capture surface of the web. Under our laboratory experimental conditions, spiders with one or two lost legs did not present any difference in prey capture efficiency. In laboratory conditions, spiders with lost leg(s) did not show any difference in egg sac production or in longevity (adult lifespan) compared to intact spiders.

  7. Coffee as an Antidote to Knowledge Stickiness

    ERIC Educational Resources Information Center

    Blackman, Deborah; Phillips, Diane

    2011-01-01

    This paper considers the concept of space and its role in both knowledge creation and overcoming knowledge stickiness. Aristotelian concepts of "freedom to" and "freedom from" are used to reconceptualise space. Informal and formal spaces, concepts and places are discussed as both specific locations and as gaps providing space for knowledge…

  8. The Discrete Site Sticky Wall Model.

    DTIC Science & Technology

    1986-05-27

    TECHNICAL REPORT #23 THE DISCRETE SITE STICKY WALL tMDEL by J.P. Badiali Laboratoire Propre No 15 de CNRS Physique des Liquides et Electrochimie Tour 22, 5e...Liquides et Electrochimie NTIS CRA&I DTIC TAB 5 Tour 22, 5e Etage, 4 Place Jussieu U’annou;.ced . J ’ tificatlo rn

  9. A golden orb-weaver spider (Araneae: Nephilidae: Nephila) from the Middle Jurassic of China.

    PubMed

    Selden, Paul A; Shih, ChungKun; Ren, Dong

    2011-10-23

    Nephila are large, conspicuous weavers of orb webs composed of golden silk, in tropical and subtropical regions. Nephilids have a sparse fossil record, the oldest described hitherto being Cretaraneus vilaltae from the Cretaceous of Spain. Five species from Neogene Dominican amber and one from the Eocene of Florissant, CO, USA, have been referred to the extant genus Nephila. Here, we report the largest known fossil spider, Nephila jurassica sp. nov., from Middle Jurassic (approx. 165 Ma) strata of Daohugou, Inner Mongolia, China. The new species extends the fossil record of the family by approximately 35 Ma and of the genus Nephila by approximately 130 Ma, making it the longest ranging spider genus known. Nephilidae originated somewhere on Pangaea, possibly the North China block, followed by dispersal almost worldwide before the break-up of the supercontinent later in the Mesozoic. The find suggests that the palaeoclimate was warm and humid at this time. This giant fossil orb-weaver provides evidence of predation on medium to large insects, well known from the Daohugou beds, and would have played an important role in the evolution of these insects.

  10. Catapulting tentacles in a sticky carnivorous plant.

    PubMed

    Poppinga, Simon; Hartmeyer, Siegfried Richard Heinrich; Seidel, Robin; Masselter, Tom; Hartmeyer, Irmgard; Speck, Thomas

    2012-01-01

    Among trapping mechanisms in carnivorous plants, those termed 'active' have especially fascinated scientists since Charles Darwin's early works because trap movements are involved. Fast snap-trapping and suction of prey are two of the most spectacular examples for how these plants actively catch animals, mainly arthropods, for a substantial nutrient supply. We show that Drosera glanduligera, a sundew from southern Australia, features a sophisticated catapult mechanism: Prey animals walking near the edge of the sundew trigger a touch-sensitive snap-tentacle, which swiftly catapults them onto adjacent sticky glue-tentacles; the insects are then slowly drawn within the concave trap leaf by sticky tentacles. This is the first detailed documentation and analysis of such catapult-flypaper traps in action and highlights a unique and surprisingly complex mechanical adaptation to carnivory.

  11. Catapulting Tentacles in a Sticky Carnivorous Plant

    PubMed Central

    Poppinga, Simon; Hartmeyer, Siegfried Richard Heinrich; Seidel, Robin; Masselter, Tom; Hartmeyer, Irmgard; Speck, Thomas

    2012-01-01

    Among trapping mechanisms in carnivorous plants, those termed ‘active’ have especially fascinated scientists since Charles Darwin’s early works because trap movements are involved. Fast snap-trapping and suction of prey are two of the most spectacular examples for how these plants actively catch animals, mainly arthropods, for a substantial nutrient supply. We show that Drosera glanduligera, a sundew from southern Australia, features a sophisticated catapult mechanism: Prey animals walking near the edge of the sundew trigger a touch-sensitive snap-tentacle, which swiftly catapults them onto adjacent sticky glue-tentacles; the insects are then slowly drawn within the concave trap leaf by sticky tentacles. This is the first detailed documentation and analysis of such catapult-flypaper traps in action and highlights a unique and surprisingly complex mechanical adaptation to carnivory. PMID:23049849

  12. Identification and Structural Characterization of the N-terminal Amyloid Core of Orb2 isoform A

    PubMed Central

    Cervantes, Silvia A.; Bajakian, Thalia H.; Soria, Maria A.; Falk, Alexander S.; Service, Rachel J.; Langen, Ralf; Siemer, Ansgar B.

    2016-01-01

    Orb2 is a functional amyloid that plays a key role in Drosophila long-term memory formation. Orb2 has two isoforms that differ in their N-termini. The N-terminus of the A isoform (Orb2A) that precedes its Q-rich prion-like domain has been shown to be important for Orb2 aggregation and long-term memory. However, besides the fact that it forms fibrillar aggregates, structural information of Orb2 is largely absent. To understand the importance of the N-terminus of Orb2A and its relation to the fibril core, we recorded solid-state NMR and EPR data on fibrils formed by the first 88 residues of Orb2A (Orb2A88). These data show that the N-terminus of Orb2A not only promotes the formation of fibrils, but also forms the fibril core of Orb2A88. This fibril core has an in-register parallel β-sheet structure and does not include the Q-rich, prion-like domain of Orb2. The Q-rich domain is part of the unstructured region, which becomes increasingly dynamic towards the C-terminus. PMID:27922050

  13. Sticky foam technology for less-than-lethal force situations

    SciTech Connect

    Goolsby, T.D.

    1994-08-01

    Sticky foam is an extremely tacky, tenacious material used to entangle and impair an individual. It was developed at Sandia National Laboratories (SNL) in the late 1970`s for usage in nuclear safeguards and security applications. In late 1992, the National Institute of Justice (NIJ), the research arm of the Department of Justice, began a project with SNL to determine the applicability of sticky foam for law enforcement usage. The objectives of the project were to develop a dispenser capable of firing sticky foam, to conduct an extensive toxicology review of sticky foam (formulation SF-283), to test the developed dispenser and sticky foam effectiveness on SNL volunteers acting out prison and law enforcement scenarios, and to have the dispenser and sticky foam further evaluated by correctional representatives. This paper discusses the results of the project.

  14. Sticky foam as a less-than-lethal technology

    SciTech Connect

    Scott, S.H.

    1996-12-31

    Sandia National Labs (SNL) in 1994 completed a project funded by the National Institute of Justice (NIJ) to determine the applicability of sticky foam for correctional applications. Sticky foam is an extremely tacky, tenacious material used to block, entangle, and impair individuals. The NIJ project developed a gun capable of firing multiple shots of sticky foam, tested the gun and sticky foam effectiveness on SNL volunteers acting out prison and law enforcement scenarios, and had the gun and sticky foam evaluated by correctional representatives. Based on the NIJ project work, SNL supported the Marine Corps Mission, Operation United Shield, with sticky foam guns and supporting equipment to assist in the withdrawal of UN Peacekeepers from Somalia. Prior to the loan of the equipment, the Marines were given training in sticky foam characterization, toxicology, safety issues, cleanup and waste disposal, use limitations, use protocol and precautions, emergency facial clean-up, skin cleanup, gun filling, targeting and firing, and gun cleaning. The Marine Corps successfully used the sticky foam guns as part of that operation. This paper describes these recent developments of sticky foam for non-lethal uses and some of the lessons learned from scenario and application testing.

  15. Reconstructing web evolution and spider diversification in the molecular era.

    PubMed

    Blackledge, Todd A; Scharff, Nikolaj; Coddington, Jonathan A; Szüts, Tamas; Wenzel, John W; Hayashi, Cheryl Y; Agnarsson, Ingi

    2009-03-31

    The evolutionary diversification of spiders is attributed to spectacular innovations in silk. Spiders are unique in synthesizing many different kinds of silk, and using silk for a variety of ecological functions throughout their lives, particularly to make prey-catching webs. Here, we construct a broad higher-level phylogeny of spiders combining molecular data with traditional morphological and behavioral characters. We use this phylogeny to test the hypothesis that the spider orb web evolved only once. We then examine spider diversification in relation to different web architectures and silk use. We find strong support for a single origin of orb webs, implying a major shift in the spinning of capture silk and repeated loss or transformation of orb webs. We show that abandonment of costly cribellate capture silk correlates with the 2 major diversification events in spiders (1). Replacement of cribellate silk by aqueous silk glue may explain the greater diversity of modern orb-weaving spiders (Araneoidea) compared with cribellate orb-weaving spiders (Deinopoidea) (2). Within the "RTA clade," which is the sister group to orb-weaving spiders and contains half of all spider diversity, >90% of species richness is associated with repeated loss of cribellate silk and abandonment of prey capture webs. Accompanying cribellum loss in both groups is a release from substrate-constrained webs, whether by aerially suspended webs, or by abandoning webs altogether. These behavioral shifts in silk and web production by spiders thus likely played a key role in the dramatic evolutionary success and ecological dominance of spiders as predators of insects.

  16. Sticky foam as a less-than-lethal technology

    NASA Astrophysics Data System (ADS)

    Scott, Steven H.

    1997-01-01

    Sandia National Laboratories (SNL) in 1994 completed a project funded by the National Institute of Justice (NIJ) to determine the applicability of sticky foam for correctional applications. Sticky foam is an extremely tacky, tenacious material used to block, entangle, and impair individuals. The NIJ project developed a gun capable of firing multiple shots of sticky foam, tested the gun and sticky foam effectiveness on SNL volunteers acting out prison and law enforcement scenarios, and had the gun and sticky foam evaluated by correctional representatives. Based on the NIJ project work, SNL supported the Marine Corps Mission, Operation United Shield, with sticky foam guns and supporting equipment to assist in the withdrawal of UN Peacekeepers from Somalia. Prior to the loan of the waste disposal, use limitations, use protocol and precautions, emergency facial clean-up, skin clean-up, gun filling, targeting and firing, and gun cleaning. The Marine Corps successfully used the sticky foam guns as part of that operation. This paper describes these recent developments of sticky foam for non-lethal uses and some of the lessons learned from scenario and application testing.

  17. Human Brain Activity Related to the Tactile Perception of Stickiness.

    PubMed

    Yeon, Jiwon; Kim, Junsuk; Ryu, Jaekyun; Park, Jang-Yeon; Chung, Soon-Cheol; Kim, Sung-Phil

    2017-01-01

    While the perception of stickiness serves as one of the fundamental dimensions for tactile sensation, little has been elucidated about the stickiness sensation and its neural correlates. The present study investigated how the human brain responds to perceived tactile sticky stimuli using functional magnetic resonance imaging (fMRI). To evoke tactile perception of stickiness with multiple intensities, we generated silicone stimuli with varying catalyst ratios. Also, an acrylic sham stimulus was prepared to present a condition with no sticky sensation. From the two psychophysics experiments-the methods of constant stimuli and the magnitude estimation-we could classify the silicone stimuli into two groups according to whether a sticky perception was evoked: the Supra-threshold group that evoked sticky perception and the Infra-threshold group that did not. In the Supra-threshold vs. Sham contrast analysis of the fMRI data using the general linear model (GLM), the contralateral primary somatosensory area (S1) and ipsilateral dorsolateral prefrontal cortex (DLPFC) showed significant activations in subjects, whereas no significant result was found in the Infra-threshold vs. Sham contrast. This result indicates that the perception of stickiness not only activates the somatosensory cortex, but also possibly induces higher cognitive processes. Also, the Supra- vs. Infra-threshold contrast analysis revealed significant activations in several subcortical regions, including the pallidum, putamen, caudate and thalamus, as well as in another region spanning the insula and temporal cortices. These brain regions, previously known to be related to tactile discrimination, may subserve the discrimination of different intensities of tactile stickiness. The present study unveils the human neural correlates of the tactile perception of stickiness and may contribute to broadening the understanding of neural mechanisms associated with tactile perception.

  18. Human Brain Activity Related to the Tactile Perception of Stickiness

    PubMed Central

    Yeon, Jiwon; Kim, Junsuk; Ryu, Jaekyun; Park, Jang-Yeon; Chung, Soon-Cheol; Kim, Sung-Phil

    2017-01-01

    While the perception of stickiness serves as one of the fundamental dimensions for tactile sensation, little has been elucidated about the stickiness sensation and its neural correlates. The present study investigated how the human brain responds to perceived tactile sticky stimuli using functional magnetic resonance imaging (fMRI). To evoke tactile perception of stickiness with multiple intensities, we generated silicone stimuli with varying catalyst ratios. Also, an acrylic sham stimulus was prepared to present a condition with no sticky sensation. From the two psychophysics experiments–the methods of constant stimuli and the magnitude estimation—we could classify the silicone stimuli into two groups according to whether a sticky perception was evoked: the Supra-threshold group that evoked sticky perception and the Infra-threshold group that did not. In the Supra-threshold vs. Sham contrast analysis of the fMRI data using the general linear model (GLM), the contralateral primary somatosensory area (S1) and ipsilateral dorsolateral prefrontal cortex (DLPFC) showed significant activations in subjects, whereas no significant result was found in the Infra-threshold vs. Sham contrast. This result indicates that the perception of stickiness not only activates the somatosensory cortex, but also possibly induces higher cognitive processes. Also, the Supra- vs. Infra-threshold contrast analysis revealed significant activations in several subcortical regions, including the pallidum, putamen, caudate and thalamus, as well as in another region spanning the insula and temporal cortices. These brain regions, previously known to be related to tactile discrimination, may subserve the discrimination of different intensities of tactile stickiness. The present study unveils the human neural correlates of the tactile perception of stickiness and may contribute to broadening the understanding of neural mechanisms associated with tactile perception. PMID:28163677

  19. Exploring the shock response of spider webs.

    PubMed

    Tietsch, V; Alencastre, J; Witte, H; Torres, F G

    2016-03-01

    Spider orb-webs are designed to allow for quick energy absorption as well as the constraint of drastic oscillations occurring upon prey impact. Studies on spider silk illustrate its impressive mechanical properties and its capacity to be used as technical fibers in composite materials. Models have previously been used to study the mechanical properties of different silk fibers, but not the behavior of the spider web as a whole. Full spider webs have been impacted by a projectile and the transverse displacement was measured by means of a laser interferometer. The damping and stiffness of the entire webs were quantified considering the orb-web as a single-degree-of-freedom (SDOF) system. The amplitude, the period duration, and the energy dissipation of the oscillations have also been reported from the experiments. The analysis of the energy dissipation confirmed that the webs of orb-web spiders are optimized for the capture of a single or few large prey, rather than several small prey. The experiments also confirmed that the overall stiffness of the web displayed a non-linear behavior. Such non-linearity was also observed in the damping characteristics of the webs studied.

  20. Optimal web investment in sub-optimal foraging conditions

    NASA Astrophysics Data System (ADS)

    Harmer, Aaron M. T.; Kokko, Hanna; Herberstein, Marie E.; Madin, Joshua S.

    2012-01-01

    Orb web spiders sit at the centre of their approximately circular webs when waiting for prey and so face many of the same challenges as central-place foragers. Prey value decreases with distance from the hub as a function of prey escape time. The further from the hub that prey are intercepted, the longer it takes a spider to reach them and the greater chance they have of escaping. Several species of orb web spiders build vertically elongated ladder-like orb webs against tree trunks, rather than circular orb webs in the open. As ladder web spiders invest disproportionately more web area further from the hub, it is expected they will experience reduced prey gain per unit area of web investment compared to spiders that build circular webs. We developed a model to investigate how building webs in the space-limited microhabitat on tree trunks influences the optimal size, shape and net prey gain of arboricolous ladder webs. The model suggests that as horizontal space becomes more limited, optimal web shape becomes more elongated, and optimal web area decreases. This change in web geometry results in decreased net prey gain compared to webs built without space constraints. However, when space is limited, spiders can achieve higher net prey gain compared to building typical circular webs in the same limited space. Our model shows how spiders optimise web investment in sub-optimal conditions and can be used to understand foraging investment trade-offs in other central-place foragers faced with constrained foraging arenas.

  1. Off-Reservation Boarding School Project (ORBS Project). Research and Evaluation Report No. 11.

    ERIC Educational Resources Information Center

    Bureau of Indian Affairs (Dept. of Interior), Albuquerque, NM.

    Pilot projects to experiment with methods of achieving the objectives of the Off-Reservation Boarding School Project (ORBS) were conducted at Sherman Indian High School, Riverside, California, and at Chilocco Indian High School, Chilocco, Oklahoma. The general objectives for the ORBS Project at each school were to review long range goals, to…

  2. Rasputin Functions as a Positive Regulator of Orb in Drosophila Oogenesis

    PubMed Central

    Sinsimer, Kristina S.; Wong, Li Chin; McLeod, Ian; Yates, John; Haynes, Susan; Schedl, Paul

    2013-01-01

    The determination of cell fate and the establishment of polarity axes during Drosophila oogenesis depend upon pathways that localize mRNAs within the egg chamber and control their on-site translation. One factor that plays a central role in regulating on-site translation of mRNAs is Orb. Orb is a founding member of the conserved CPEB family of RNA-binding proteins. These proteins bind to target sequences in 3′ UTRs and regulate mRNA translation by modulating poly(A) tail length. In addition to controlling the translation of axis-determining mRNAs like grk, fs(1)K10, and osk, Orb protein autoregulates its own synthesis by binding to orb mRNA and activating its translation. We have previously shown that Rasputin (Rin), the Drosophila homologue of Ras-GAP SH3 Binding Protein (G3BP), associates with Orb in a messenger ribonucleoprotein (mRNP) complex. Rin is an evolutionarily conserved RNA-binding protein believed to function as a link between Ras signaling and RNA metabolism. Here we show that Orb and Rin form a complex in the female germline. Characterization of a new rin allele shows that rin is essential for oogenesis. Co-localization studies suggest that Orb and Rin form a complex in the oocyte at different stages of oogenesis. This is supported by genetic and biochemical analyses showing that rin functions as a positive regulator in the orb autoregulatory pathway by increasing Orb protein expression. Tandem Mass Spectrometry analysis shows that several canonical stress granule proteins are associated with the Orb-Rin complex suggesting that a conserved mRNP complex regulates localized translation during oogenesis in Drosophila. PMID:24069162

  3. Rasputin functions as a positive regulator of orb in Drosophila oogenesis.

    PubMed

    Costa, Alexandre; Pazman, Cecilia; Sinsimer, Kristina S; Wong, Li Chin; McLeod, Ian; Yates, John; Haynes, Susan; Schedl, Paul

    2013-01-01

    The determination of cell fate and the establishment of polarity axes during Drosophila oogenesis depend upon pathways that localize mRNAs within the egg chamber and control their on-site translation. One factor that plays a central role in regulating on-site translation of mRNAs is Orb. Orb is a founding member of the conserved CPEB family of RNA-binding proteins. These proteins bind to target sequences in 3' UTRs and regulate mRNA translation by modulating poly(A) tail length. In addition to controlling the translation of axis-determining mRNAs like grk, fs(1)K10, and osk, Orb protein autoregulates its own synthesis by binding to orb mRNA and activating its translation. We have previously shown that Rasputin (Rin), the Drosophila homologue of Ras-GAP SH3 Binding Protein (G3BP), associates with Orb in a messenger ribonucleoprotein (mRNP) complex. Rin is an evolutionarily conserved RNA-binding protein believed to function as a link between Ras signaling and RNA metabolism. Here we show that Orb and Rin form a complex in the female germline. Characterization of a new rin allele shows that rin is essential for oogenesis. Co-localization studies suggest that Orb and Rin form a complex in the oocyte at different stages of oogenesis. This is supported by genetic and biochemical analyses showing that rin functions as a positive regulator in the orb autoregulatory pathway by increasing Orb protein expression. Tandem Mass Spectrometry analysis shows that several canonical stress granule proteins are associated with the Orb-Rin complex suggesting that a conserved mRNP complex regulates localized translation during oogenesis in Drosophila.

  4. The Aggregate Supply Curve: Keynes and Downwardly Sticky Money Wages.

    ERIC Educational Resources Information Center

    Wells, Paul

    1985-01-01

    Keynes's explanation of both the rationale underlying downwardly sticky money wages and the consequences this phenomenon has for macroeconomic theory are reviewed. An aggregate supply curve appropriate to today's economy is then interpreted. (Author/RM)

  5. Sticky bomb detection with other implications for vehicle security.

    SciTech Connect

    Johnston, R. G.; Vetrone, J.; Warner, J. S.

    2010-01-01

    A 'sticky bomb' is a type of improvised explosive device (IED) placed on a motor vehicle by (for example) a terrorist. The bomb is typically attached with adhesive ('duct') tape, or with magnets. This paper reports some preliminary results for a very rudimentary demonstration of two techniques for detecting the placement of a sticky bomb on a motor vehicle. The two techniques are tire pressure and magnetic measurements. There are other possible security applications for these techniques as well.

  6. Are neighborhoods causal? Complications arising from the 'stickiness' of ZNA.

    PubMed

    Glass, Thomas A; Bilal, Usama

    2016-10-01

    Are neighborhoods causal? The answer remains elusive. Armed with new multilevel methods, enthusiasm for neighborhoods research surged at the turn of the century. However, a wave of skepticism has arisen based on the difficulty of drawing causal inferences from observational studies in which selection to neighborhoods is non-random. Researchers have sought answers from experimental and quasi-experimental studies of movers vs. stayers. We develop two related concepts in this essay in the hopes of shedding light on this problem. First, the inceptive environment into which persons are born (which we term ZNA for Zip code Nativity Area) exerts a potentially powerful causal impact on health. Detecting that causal effect is challenging for reasons similar that obtain in other fields (including genetics). Second, we explicate the problem of neighborhood 'stickiness' in terms of the persistence of neighborhood treatment assignment, and argue that under-appreciation of stickiness has led to systematic bias in causal estimates of neighborhoods proportional to the degree of stickiness. In sticky contexts, failure to account for the lasting influences of ZNA by adjusting for intermediate individual socioeconomic and health variables on the causal pathway can result in neighborhood effects estimates that are biased toward the null. We follow with an example drawn from evidence of neighborhood 'stickiness' and obesity. The stickiness of ZNA cautions us that experimental evidence may be insufficient or misleading as a solution to causal inference problems in neighborhood research.

  7. Sticky fingers: Adhesive properties of human fingertips.

    PubMed

    Spinner, Marlene; Wiechert, Anke B; Gorb, Stanislav N

    2016-02-29

    Fingertip friction is a rather well studied subject. Although the phenomenon of finger stickiness is known as well, the pull-off force and the adhesive strength of human finger tips have never been previously quantified. For the first time, we provided here characterization of adhesive properties of human fingers under natural conditions. Human fingers can generate a maximum adhesive force of 15mN on a smooth surface of epoxy resin. A weak correlation of the adhesive force and the normal force was found on all test surfaces. Up to 300mN load, an increase of the normal force leads to an increase of the adhesive force. On rough surfaces, the adhesive strength is significantly reduced. Our data collected from untreated hands give also an impression of an enormous scattering of digital adhesion depending on a large set of inter-subject variability and time-dependent individual factors (skin texture, moisture level, perspiration). The wide inter- and intra-individual range of digital adhesion should be considered in developing of technical and medical products.

  8. Sticky platelet syndrome: history and future perspectives.

    PubMed

    Kubisz, Peter; Ruiz-Argüelles, Guillermo J; Stasko, Jan; Holly, Pavol; Ruiz-Delgado, Guillermo J

    2014-07-01

    The sticky platelet syndrome (SPS) is a thrombophilic qualitative platelet disorder with familial occurrence and autosomal dominant trait, characterized by increased in vitro platelet aggregation after low concentrations of adenosine diphosphate and/or epinephrine. Its clinical manifestation includes arterial thrombosis, pregnancy complications (fetal growth retardation and fetal loss), and less often venous thromboembolism. SPS was considered to be a rare thrombophilic disorder, but it can be found relatively often as a cause of unexplained thrombosis, particularly among patients with arterial thrombosis such as stroke. The syndrome was recognized as a distinct disorder in 1983 by Holiday and further characterized in the 1980s and 1990s, with Mammen and Bick providing the key findings. Although recognized for more than 30 years, significant issues, namely the syndrome's etiology, inheritance, and epidemiology, remain unclear. The aim of the first part of this review is to summarize the previous 35 years of the research into, and to provide a brief historical account of, SPS. The history section is focused particularly on the work of two most prominent investigators: Eberhard F. Mammen and Rodger L. Bick. The second part summarizes the present understanding of the syndrome and outlines unresolved issues and the trends in which the future research is likely to continue.

  9. Bioprospecting Finds the Toughest Biological Material: Extraordinary Silk from a Giant Riverine Orb Spider

    PubMed Central

    Agnarsson, Ingi; Kuntner, Matjaž; Blackledge, Todd A.

    2010-01-01

    Background Combining high strength and elasticity, spider silks are exceptionally tough, i.e., able to absorb massive kinetic energy before breaking. Spider silk is therefore a model polymer for development of high performance biomimetic fibers. There are over 41.000 described species of spiders, most spinning multiple types of silk. Thus we have available some 200.000+ unique silks that may cover an amazing breadth of material properties. To date, however, silks from only a few tens of species have been characterized, most chosen haphazardly as model organisms (Nephila) or simply from researchers' backyards. Are we limited to ‘blindly fishing’ in efforts to discover extraordinary silks? Or, could scientists use ecology to predict which species are likely to spin silks exhibiting exceptional performance properties? Methodology We examined the biomechanical properties of silk produced by the remarkable Malagasy ‘Darwin's bark spider’ (Caerostris darwini), which we predicted would produce exceptional silk based upon its amazing web. The spider constructs its giant orb web (up to 2.8 m2) suspended above streams, rivers, and lakes. It attaches the web to substrates on each riverbank by anchor threads as long as 25 meters. Dragline silk from both Caerostris webs and forcibly pulled silk, exhibits an extraordinary combination of high tensile strength and elasticity previously unknown for spider silk. The toughness of forcibly silked fibers averages 350 MJ/m3, with some samples reaching 520 MJ/m3. Thus, C. darwini silk is more than twice tougher than any previously described silk, and over 10 times better than Kevlar®. Caerostris capture spiral silk is similarly exceptionally tough. Conclusions Caerostris darwini produces the toughest known biomaterial. We hypothesize that this extraordinary toughness coevolved with the unusual ecology and web architecture of these spiders, decreasing the likelihood of bridgelines breaking and collapsing the web into the river

  10. Effects of kaolin particle films on the life span of an orb-weaver spider.

    PubMed

    Benhadi-Marín, Jacinto; Pereira, José Alberto; Santos, Sónia A P

    2016-02-01

    Araniella cucurbitina (Araneae: Araneidae) is a widespread orb-weaver spider commonly found in agroecosystems. Mineral particle films such as kaolin, due to their protective or anti-feeding action, can represent an alternative to pesticides, especially in organic farming systems, but little is known about its effects on A. cucurbitina. Therefore, we tested the effect of kaolin sprays on the life span of A. cucurbitina under laboratory conditions. Four treatments were tested encompassing different exposure routes. Thus, kaolin sprays were applied on (i) the surface, (ii) the prey (fly), (iii) the spider and (iv) both spider & prey. A control group was tested with water in each treatment. Results showed that sprays of kaolin significantly affected the survival of A. curcubitina when applications were done on the surface and on both spider & prey registering a reduction of 48% and 56%, respectively. Spiders in control obtained higher probability of reaching alive at the end of the assay than those treated with kaolin. Differences observed can be explained by the feeding behavior of the species and may depend on the consumption of the web by the spider and the ratio spider/fly for body size.

  11. ORBS: A reduction software for SITELLE and SpiOMM data

    NASA Astrophysics Data System (ADS)

    Martin, Thomas

    2014-09-01

    ORBS merges, corrects, transforms and calibrates interferometric data cubes and produces a spectral cube of the observed region for analysis. It is a fully automatic data reduction software for use with SITELLE (installed at the Canada-France-Hawaii Telescope) and SpIOMM (a prototype attached to the Observatoire du Mont Mégantic); these imaging Fourier transform spectrometers obtain a hyperspectral data cube which samples a 12 arc-minutes field of view into 4 millions of visible spectra. ORBS is highly parallelized; its core classes (ORB) have been designed to be used in a suite of softwares for data analysis (ORCS and OACS), data simulation (ORUS) and data acquisition (IRIS).

  12. Geolocation Accuracy Evaluations of OrbView-3, EROS-A, and SPOT-5 Imagery

    NASA Technical Reports Server (NTRS)

    Bresnahan, Paul

    2007-01-01

    This viewgraph presentation evaluates absolute geolocation accuracy of OrbView-3, EROS-A, and SPOT-5 by comparing test imagery-derived ground coordinates to Ground Control Points using SOCET set photogrammetric software.

  13. Web-building time in a spider: preliminary applications of ultrasonic detection.

    PubMed

    Ramousse, R; Davis, F

    1976-12-01

    Data collection on time and length of building in orb-weaving spiders has suffered from absence of light during construction and inconvenient hours. A simple apparatus is described which permits recording of the spiders' movements as they disturb an ultrasonic field. By varying onset and length of dark periods for two animals at even temperature and by registering the building periods for 127 webs, a definite influence of the light-dark cycle can be identified: there is a strong preference for building webs in the dark; this is superimposed on the circadian rhythm of orb-web construction. One of the spiders always built earlier than the other.

  14. In search of ice-stream sticky spots

    NASA Technical Reports Server (NTRS)

    Alley, Richard B.

    1993-01-01

    The form drag of large bedrock bumps sticking into the base of an ice stream can produce effective 'sticky spots' supporting large basal shear stress. Bedrock regions surrounded by lubricating till at the same topographic level can cause sticky spots, but tend to collect lubricating water and thus are unlikely to support a shear stress of more than a few tenths of a bar unless they contain abundant large bumps. Raised regions on the ice-air surface also can cause moderate increases in the shear stress supported on the bed beneath. Surveys of large-scale bedrock roughness, strain grids across the margins of ice-surface highs, and possibly, water-pressure measurements in regions of thin or zero till would help identify and characterize sticky spots.

  15. Amyloidogenic oligomerization transforms Drosophila Orb2 from a translation repressor to an activator

    PubMed Central

    Khan, Mohammed ‘Repon’; Li, Liying; Pérez-Sánchez, Consuelo; Saraf, Anita; Florens, Laurence; Slaughter, Brian D.; Unruh, Jay R.; Si, Kausik

    2015-01-01

    Memories are thought to be formed in response to transient experiences in part through changes in local protein synthesis at synapses. In Drosophila, the amyloidogenic (prion-like) state of the RNA binding protein Orb2 has been implicated in long-term memory, but how conformational conversion of Orb2 promotes memory formation is unclear. Combining in vitro and in vivo studies, we find that the monomeric form of Orb2 represses translation and removes mRNA polyA tails, while the oligomeric form enhances translation and elongates the polyA tails, and imparts its translational state to the monomer. The CG13928 protein, which binds only to monomeric Orb2, promotes deadenylation, whereas the putative polyA binding protein CG4612 promotes oligomeric Orb2-dependent translation. Our data support a model in which monomeric Orb2 keeps target mRNA in a translationally dormant state, and experience-dependent conversion to the amyloidogenic state activates translation, resulting in persistent alteration of synaptic activity and stabilization of memory. PMID:26638074

  16. Amyloidogenic Oligomerization Transforms Drosophila Orb2 from a Translation Repressor to an Activator.

    PubMed

    Khan, Mohammed Repon; Li, Liying; Pérez-Sánchez, Consuelo; Saraf, Anita; Florens, Laurence; Slaughter, Brian D; Unruh, Jay R; Si, Kausik

    2015-12-03

    Memories are thought to be formed in response to transient experiences, in part through changes in local protein synthesis at synapses. In Drosophila, the amyloidogenic (prion-like) state of the RNA binding protein Orb2 has been implicated in long-term memory, but how conformational conversion of Orb2 promotes memory formation is unclear. Combining in vitro and in vivo studies, we find that the monomeric form of Orb2 represses translation and removes mRNA poly(A) tails, while the oligomeric form enhances translation and elongates the poly(A) tails and imparts its translational state to the monomer. The CG13928 protein, which binds only to monomeric Orb2, promotes deadenylation, whereas the putative poly(A) binding protein CG4612 promotes oligomeric Orb2-dependent translation. Our data support a model in which monomeric Orb2 keeps target mRNA in a translationally dormant state and experience-dependent conversion to the amyloidogenic state activates translation, resulting in persistent alteration of synaptic activity and stabilization of memory.

  17. Tools made of ice facilitate forming of soft, sticky materials

    NASA Technical Reports Server (NTRS)

    Harris, J. E.; Ramsey, J. G., Jr.; Schinbeckler, K. D.

    1969-01-01

    Tools made of ice facilitate the forming or shaping of materials that are soft and sticky in the uncured state. The low-temperature of the ice slows the curing of the material, extending the working time available before setup. Handling problems are eliminated because the material does not adhere to the tool, and the melting ice serves as a lubricant.

  18. Analysis of major ampullate silk cDNAs from two non-orb-weaving spiders.

    PubMed

    Tian, Maozhen; Liu, Congzhou; Lewis, Randolph

    2004-01-01

    Compared to other arthropods, spiders are unique in their use of silk throughout their life span and the extraordinary mechanical properties of the silk threads they produce. Studies on orb-weaving spider silk proteins have shown that silk proteins are composed of highly repetitive regions, characterized by alanine and glycine-rich units. We have isolated and sequenced four partial cDNA clones representing major ampullate spider silk gene transcripts from two non-orb weavers: three for Kukulcania hibernalis and one for Agelenopsis aperta. These cDNA sequences were compared to each other, as well as to the previously published orb-weaver silk gene sequences. The results indicate that the repeats encoding conserved amino acid motifs such as polyA and polyGA that are characteristic of some orb-weaving spider silks are also found in some of the cDNAs reported in this study. However, we also found other motifs such as polyGS and polyGV in the cDNA sequences from the two non-orb-weaving spiders. The amino acid composition of the silk gland extracts shows that alanine and glycine are the major components of the silk of these two non-orb weavers as is the case in orb-weaver silks. Sequence alignment shows that A. aperta's cDNA displays a C-terminal encoding region that is about 44% similar to the one present in N. clavipes's MaSp1 cDNA. In addition, as previously observed for spider silk sequences, the analysis of the codon usage for these four cDNAs demonstrates a bias for A or T in the wobble base position.

  19. Molecular Basis of Orb2 Amyloidogenesis and Blockade of Memory Consolidation

    PubMed Central

    Majumdar, Amitabha; Fernández-Ramírez, María del Carmen; Unruh, Jay R.; Slaughter, Brian D.; Galera-Prat, Albert; Santana, Elena; Suzuki, Mari; Nagai, Yoshitaka; Bruix, Marta; Casas-Tintó, Sergio; Menéndez, Margarita; Laurents, Douglas V.; Si, Kausik; Carrión-Vázquez, Mariano

    2016-01-01

    Amyloids are ordered protein aggregates that are typically associated with neurodegenerative diseases and cognitive impairment. By contrast, the amyloid-like state of the neuronal RNA binding protein Orb2 in Drosophila was recently implicated in memory consolidation, but it remains unclear what features of this functional amyloid-like protein give rise to such diametrically opposed behaviour. Here, using an array of biophysical, cell biological and behavioural assays we have characterized the structural features of Orb2 from the monomer to the amyloid state. Surprisingly, we find that Orb2 shares many structural traits with pathological amyloids, including the intermediate toxic oligomeric species, which can be sequestered in vivo in hetero-oligomers by pathological amyloids. However, unlike pathological amyloids, Orb2 rapidly forms amyloids and its toxic intermediates are extremely transient, indicating that kinetic parameters differentiate this functional amyloid from pathological amyloids. We also observed that a well-known anti-amyloidogenic peptide interferes with long-term memory in Drosophila. These results provide structural insights into how the amyloid-like state of the Orb2 protein can stabilize memory and be nontoxic. They also provide insight into how amyloid-based diseases may affect memory processes. PMID:26812143

  20. The effects of neurotoxins on web-geometry and web-building behaviour in Araneus diadematus Cl.

    PubMed

    Hesselberg, Thomas; Vollrath, Fritz

    2004-09-15

    The process of orb weaving and the resultant orb web constitute a good example of a complex behavioural pattern that is still governed by a relatively simple set of rules. We used the orb spider Araneus diadematus as a model organism to study the effect of the three neurotoxins (scopolamine, amphetamine, and caffeine) on the spider's behaviour. Scopolamine was given at two concentrations, with the lower one showing no effects but the higher one reducing web-building frequency; there also appeared to be a weak effect on web geometry. Amphetamine and caffeine, on the other hand, both resulted in significant changes in both building frequency and web geometry, compared to the controls. Amphetamine webs retained their size but showed an increase in spiral spacing and radius irregularity, as well as a decrease in building efficiency. Caffeine led to a general decrease in size and a slight increase in spiral spacing, as well as radius irregularity. Furthermore, caffeine caused webs to be rounder. Our observations suggest that these neurotoxins disturb different parts of the web-building programme presumably by affecting different actions in the spider's CNS.

  1. Simple Model for the Mechanics of Spider Webs

    NASA Astrophysics Data System (ADS)

    Aoyanagi, Yuko; Okumura, Ko

    2010-01-01

    We propose a simple model to describe spider orb webs. The model has a formal analytical solution when no thread elements are broken. When the radial threads are sufficiently strong compared to the spiral threads, the model is free of stress concentrations even when a few spiral threads are broken. This is in contrast with what occurs in common elastic materials. According to our model, spiders can increase the number of spiral threads to make a dense web (to catch small insects) or adjust the number of radial threads (to adapt to environmental conditions or reduce the cost of making the web) without reducing the damage tolerance of the web.

  2. Free energy of singular sticky-sphere clusters

    NASA Astrophysics Data System (ADS)

    Kallus, Yoav; Holmes-Cerfon, Miranda

    2017-02-01

    Networks of particles connected by springs model many condensed-matter systems, from colloids interacting with a short-range potential and complex fluids near jamming, to self-assembled lattices and various metamaterials. Under small thermal fluctuations the vibrational entropy of a ground state is given by the harmonic approximation if it has no zero-frequency vibrational modes, yet such singular modes are at the epicenter of many interesting behaviors in the systems above. We consider a system of N spherical particles, and directly account for the singularities that arise in the sticky limit where the pairwise interaction is strong and short ranged. Although the contribution to the partition function from singular clusters diverges in the limit, its asymptotic value can be calculated and depends on only two parameters, characterizing the depth and range of the potential. The result holds for systems that are second-order rigid, a geometric characterization that describes all known ground-state (rigid) sticky clusters. To illustrate the applications of our theory we address the question of emergence: how does crystalline order arise in large systems when it is strongly disfavored in small ones? We calculate the partition functions of all known rigid clusters up to N ≤21 and show the cluster landscape is dominated by hyperstatic clusters (those with more than 3 N -6 contacts); singular and isostatic clusters are far less frequent, despite their extra vibrational and configurational entropies. Since the most hyperstatic clusters are close to fragments of a close-packed lattice, this underlies the emergence of order in sticky-sphere systems, even those as small as N =10 .

  3. Fine Structure of Sticky Sets in Mushroom Billiards

    NASA Astrophysics Data System (ADS)

    Bunimovich, Leonid A.

    2013-12-01

    We consider sticky sets in the phase space of circular mushroom billiards, which are referred to in physics literature as MUPOs (marginally unstable periodic orbits). An exact description of the set of parameters (widths of the mushrooms' stems) without or with a finite set of MUPOs is given. It is shown that there exist a continuum of MUPOless parameters. We also estimate from above a number of MUPOs which exist for widths of the mushroom's stem which correspond to rational numbers and present a simple approach for finding mushroom billiards without MUPOs.

  4. Measurement of Sticky Point Temperature of Coffee Powder with a Rheometer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sticky point temperature (Ts) measurement for hygroscopic food and biomaterial powders is traditionally performed with complex glass instruments. This property is used to characterize material stickiness, which substantially affects the flow and physical behavior of powders. In this research study w...

  5. Basal characteristics of the main sticky spot on the ice plain of Whillans Ice Stream, Antarctica

    NASA Astrophysics Data System (ADS)

    Luthra, Tarun; Anandakrishnan, Sridhar; Winberry, J. Paul; Alley, Richard B.; Holschuh, Nicholas

    2016-04-01

    Understanding the processes that affect streaming ice flow and the mass balance of glaciers and ice sheets requires sound knowledge of their subglacial environments. Previous studies have shown that an extensive deformable subglacial sediment layer favors fast ice-stream flow. However, areas of high basal drag, termed sticky spots, are of particular interest because they inhibit the fast flow of the overriding ice. The stick-slip behavior of Whillans Ice Stream (WIS) is perhaps the most conspicuous manifestation of a subglacial sticky spot. We present new ice-thickness and seismic-reflection measurements collected over the main sticky spot in the ice plain of WIS, allowing us to elucidate its role in the behavior of the ice stream. Ice-thickness and surface-elevation data show that the sticky spot occupies a subglacial topographic high. Water flow in response to the hydrological potential gradient will be routed around the sticky spot if effective pressures are similar on the sticky spot and elsewhere. The seismic experiment imaged a laterally continuous basal layer approximately 6 m thick, having compressional wave velocities of greater than 1800 m s-1 and density greater than 1800 kg m-3, indicative of a till layer that is stiffer than corresponding till beneath well-lubricated parts of the ice stream. This layer likely continues to deform under the higher shear stress of the sticky spot, and some water may be pumped up onto the sticky spot during motion events.

  6. Nephila clavipes spiders (Araneae: Nephilidae) keep track of captured prey counts: testing for a sense of numerosity in an orb-weaver.

    PubMed

    Rodríguez, Rafael L; Briceño, R D; Briceño-Aguilar, Eduardo; Höbel, Gerlinde

    2015-01-01

    Nephila clavipes golden orb-web spiders accumulate prey larders on their webs and search for them if they are removed from their web. Spiders that lose larger larders (i.e., spiders that lose larders consisting of more prey items) search for longer intervals, indicating that the spiders form memories of the size of the prey larders they have accumulated, and use those memories to regulate recovery efforts when the larders are pilfered. Here, we ask whether the spiders represent prey counts (i.e., numerosity) or a continuous integration of prey quantity (mass) in their memories. We manipulated larder sizes in treatments that varied in either prey size or prey numbers but were equivalent in total prey quantity (mass). We then removed the larders to elicit searching and used the spiders' searching behavior as an assay of their representations in memory. Searching increased with prey quantity (larder size) and did so more steeply with higher prey counts than with single prey of larger sizes. Thus, Nephila spiders seem to track prey quantity in two ways, but to attend more to prey numerosity. We discuss alternatives for continuous accumulator mechanisms that remain to be tested against the numerosity hypothesis, and the evolutionary and adaptive significance of evidence suggestive of numerosity in a sit-and-wait invertebrate predator.

  7. Effects of grassland succession on communities of orb-weaving spiders.

    PubMed

    Richardson, M L; Hanks, L M

    2009-12-01

    Native grasslands are among the most imperiled of the North American ecosystems, but abandoned agricultural areas may provide suitable habitat for animal taxa that are endemic to grasslands. We studied how species diversity of orb-weaving spiders was influenced by secondary succession of a grassland plant community by monitoring the abundance and species diversity in study plots that were cultivated at 6-yr intervals and left uncultivated in the interim. We tested the hypothesis that local abundance and species diversity of spiders would be positively associated with time since cultivation because plant communities in older habitats would be more architecturally complex. Local abundance of spiders in general was not associated with time since cultivation, but abundance of Mangora gibberosa (Hentz) was positively associated with the abundance of perennial plants. Species richness and diversity of spiders also were positively associated with the abundance of perennial plants and reached a threshold a few years after cultivation. Species diversity of orb-weaving spiders seems to be strongly influenced by species composition of the plant community. Therefore, effective restoration of the structure and function of endemic communities of orb-weaving spiders may depend on preserving endemic grassland plant communities.

  8. ORBS: A data reduction software for the imaging Fourier transform spectrometers SpIOMM and SITELLE

    NASA Astrophysics Data System (ADS)

    Martin, T.; Drissen, L.; Joncas, G.

    2012-09-01

    SpIOMM (Spectromètre-Imageur de l'Observatoire du Mont Mégantic) is still the only operational astronomical Imaging Fourier Transform Spectrometer (IFTS) capable of obtaining the visible spectrum of every source of light in a field of view of 12 arc-minutes. Even if it has been designed to work with both outputs of the Michelson interferometer, up to now only one output has been used. Here we present ORBS (Outils de Réduction Binoculaire pour SpIOMM/SITELLE), the reduction software we designed in order to take advantage of the two output data. ORBS will also be used to reduce the data of SITELLE (Spectromètre-Imageur pour l' Étude en Long et en Large des raies d' Émissions) { the direct successor of SpIOMM, which will be in operation at the Canada-France- Hawaii Telescope (CFHT) in early 2013. SITELLE will deliver larger data cubes than SpIOMM (up to 2 cubes of 34 Go each). We thus have made a strong effort in optimizing its performance efficiency in terms of speed and memory usage in order to ensure the best compliance with the quality characteristics discussed with the CFHT team. As a result ORBS is now capable of reducing 68 Go of data in less than 20 hours using only 5 Go of random-access memory (RAM).

  9. Icequakes! Microseismic ';Sticky Spots' in Rutford Ice Stream, West Antarctica

    NASA Astrophysics Data System (ADS)

    Smith, E. C.; Smith, A.; White, R. S.; Brisbourne, A.

    2013-12-01

    Microseismic emissions from the base of Rutford Ice Stream, West Antarctica, were recorded over a 34-day period using ten three-component instruments on the surface of the ice stream. Around 3000 microseismic events were detected and located. Events are concentrated in spatial clusters that are likely to be ';sticky spots': areas of increased basal friction where shear stress is concentrated. The ';sticky spots' turn on and off over the recording period becoming inactive for a period of time before being re-activated in the same location. The constant nature of these locations indicates a temporal stability in the basal regime despite the fact that rapid changes have been seen at the bed in this area (erosion and drumlin formation). Furthermore, events in each location cluster have a consistent waveform at a given receiver and a consistent source mechanism determined by fault plane analysis. The source mechanisms for these microseismic events show variation between clusters. Evidence of low-angled thrust faults in the ice flow direction suggest basal sliding is occurring in some regions and that in these regions basal flow is in the same orientation as surface flow, despite considerable bed topography. However, more complex source signatures in other regions indicate a spatial change in the basal processes over the survey area. An increased understanding of basal processes is fundamental in our ability to predict the evolution and future contribution to global sea level rise of ice sheets. Passive microseismic monitoring is proving to be an effective tool for investigating many aspects of this.

  10. Effect of sticky mat usage in control of nosocomial infection in Motahary Burn Hospital

    PubMed Central

    Dahmardehei, Mostafa; Alinejad, Faranak; Ansari, Fereshteh; Bahramian, Mahnaz; Barati, Mitra

    2016-01-01

    Background and Objectives: Infection is the most common cause of death among burnt patients and infection control decrease the rate of mortality. The use of sticky mat can control contamination by preventing the entrance microorganisms into the hospital wards. This study was designed to evaluate the sticky mats effect in reduction of microorganism’s entry by personnel shoes to burn intensive care unit (BICU). Materials and Methods: This is a simple cross sectional study. We tested outer soles of personnel’s shoes with swap and cultured them before and after sticky mat contact in the entrance of BICU. Results were analyzed with IBM SPSS version 22 software. McNemar and Wilcoxon Signed Ranks tests were used. Results: We analyzed 60 outer soles of the shoes before and after contact with sticky mats. Coagulase negative Staphylococci, Gram positive bacilli, Staphylococcus aureus, Aspergillus fumigatus, Pseudomonas aeruginosa and Acinetobacter baumannii were isolated before contact from 57 (95%), 32 (53%), 4 (6.7%) and 3 (5%) cases, respectively. Coagulase negative Staphylococci, Gram positive bacilli, Staphylococcus aureus, Aspergillus fumigatus, Pseudomonas aeruginosa were isolated after contact from 36 (60%), 30 (50%), 16 (26.6%), 2 (3.3%) and 3 (5%) cases, respectively. No Acinetobacter was isolated after contact with sticky mat. Total isolated colonies before and after contact with sticky mats were 2573 and 830, respectively. There were significant statistically differences between the colony counts of coagulase ngative staphylococci, Gram positive bacilli, and Staphylococci aureus before and after contact with sticky mats (P. < 0.001). Conclusion: Regarding to statistical analysis, the effect of mat in removing the microorganisms was 56%. It confirms the effectiveness of sticky mat controlling the infection and reducing the amount of hospital contamination. PMID:27928489

  11. Removal of Wax and Stickies from OCC by Flotation

    SciTech Connect

    M. R. Doshi; J. Dyer

    2000-01-31

    Laboratory research indicates that wax is amenable to removal by froth flotation provided it is free or detached from the fiber. The only effective means, at this time, of maximizing detachment of wax is through the use of low consistency pulping at temperatures above the melting point of wax. Wax removal from WCC through washing, flotation, or a combination of both was approximately 90% in these laboratory studies, indicating that not all of the wax is detached from fibers. These results were summarized in Annual Report 1, December 1, 1997 to November 30, 1998. Pilot trials were conducted in which the authors simulated a conventional OCC repulping process with and without flotation. Additional aggressive washing and water clarification were also examined during the study. The inclusion of flotation in the OCC stock preparation system significantly improved the removal of wax spots and extractable material from the furnish. Based on this study, the authors predict that a compact flotation system with 2 lb surfactant/ton of fiber would improve the OCC pulp quality with regard to wax spots by 60% and would not negatively affect strength properties. Flotation losses would be in the 2-5% range. Two mill trials were conducted during the last quarter of the project. One trial was carried out at Green Bay Packaging, Green Bay, WI, and a second trial was conducted at Menasha Corporation, Otsego, MI. A 250-liter Voith Sulzer Ecocell was used to evaluate the removal of wax and stickies from the OCC processing systems at these two mills. The inclusion of flotation in the OCC stock preparation system significantly improved the removal of wax spots from the furnish. The data indicate that flotation was more effective in removing wax and stickies than reverse cleaners. The mill trials have demonstrated that flotation can be substituted for or replace existing reverse cleaning systems and, in some cases, can replace dispersion systems. In this manner, the use of flotation can

  12. A sticky situation: the unexpected stability of malaria elimination

    PubMed Central

    Smith, David L.; Cohen, Justin M.; Chiyaka, Christinah; Johnston, Geoffrey; Gething, Peter W.; Gosling, Roly; Buckee, Caroline O.; Laxminarayan, Ramanan; Hay, Simon I.; Tatem, Andrew J.

    2013-01-01

    Malaria eradication involves eliminating malaria from every country where transmission occurs. Current theory suggests that the post-elimination challenges of remaining malaria-free by stopping transmission from imported malaria will have onerous operational and financial requirements. Although resurgent malaria has occurred in a majority of countries that tried but failed to eliminate malaria, a review of resurgence in countries that successfully eliminated finds only four such failures out of 50 successful programmes. Data documenting malaria importation and onwards transmission in these countries suggests malaria transmission potential has declined by more than 50-fold (i.e. more than 98%) since before elimination. These outcomes suggest that elimination is a surprisingly stable state. Elimination's ‘stickiness’ must be explained either by eliminating countries starting off qualitatively different from non-eliminating countries or becoming different once elimination was achieved. Countries that successfully eliminated were wealthier and had lower baseline endemicity than those that were unsuccessful, but our analysis shows that those same variables were at best incomplete predictors of the patterns of resurgence. Stability is reinforced by the loss of immunity to disease and by the health system's increasing capacity to control malaria transmission after elimination through routine treatment of cases with antimalarial drugs supplemented by malaria outbreak control. Human travel patterns reinforce these patterns; as malaria recedes, fewer people carry malaria from remote endemic areas to remote areas where transmission potential remains high. Establishment of an international resource with backup capacity to control large outbreaks can make elimination stickier, increase the incentives for countries to eliminate, and ensure steady progress towards global eradication. Although available evidence supports malaria elimination's stickiness at moderate

  13. Project O.R.B (Operation Reef Ball): Creating Artificial Reefs, Educating the Community

    NASA Astrophysics Data System (ADS)

    Phipps, A.

    2012-04-01

    The Project O.R.B. (Operation Reef Ball) team at South Plantation High School's Everglades Restoration & Environmental Science Magnet Program is trying to help our ailing south Florida coral reefs by constructing, deploying, and monitoring designed artificial reefs. Students partnered with the Reef Ball Foundation, local concrete companies, state parks, Girl Scouts, Sea Scouts, local universities and environmental agencies to construct concrete reef balls, each weighing approximately 500 lbs (227 kg). Students then deployed two artificial reefs consisting of over 30 concrete reef balls in two sites previously permitted for artificial reef deployment. One artificial reef was placed approximately 1.5 miles (2.4 km) offshore of Golden Beach in Miami-Dade County with the assistance of Florida Atlantic University and their research vessel. A twin reef was deployed at the mouth of the river in Oleta River State Park in Miami. Monitoring and maintenance of the sites is ongoing with semi-annual reports due to the Reef Ball Foundation and DERM (Department of Environmental Resource Management) of Miami-Dade County. A second goal of Project O.R.B. is aligned with the Florida Local Action Strategy, the Southeast Florida Coral Reef Initiative, and the U.S. Coral Reef Task Force, all of which point out the importance of awareness and education as key components to the health of our coral reefs. Project O.R.B. team members developed and published an activity book targeting elementary school students. Outreach events incorporate cascade learning where high school students teach elementary and middle school students about various aspects of coral reefs through interactive "edu-tainment" modules. Attendees learn about water sampling, salinity, beach erosion, surface runoff, water cycle, ocean zones, anatomy of coral, human impact on corals, and characteristics of a well-designed artificial reef. Middle school students snorkel on the artificial reef to witness first-hand the success

  14. Spider web glue: two proteins expressed from opposite strands of the same DNA sequence.

    PubMed

    Choresh, Omer; Bayarmagnai, Battuya; Lewis, Randolph V

    2009-10-12

    The various silks that make up the web of the orb web spiders have been studied extensively. However, success in prey capture depends as much on the web glue as on the fibers. Spider silk glue, which is considered one of the strongest and most effective biological glues, is an aqueous solution secreted from the orb weaving spider's aggregate glands and coats the spiral prey capturing threads of their webs. Studies identified the major component of the glue as microscopic nodules made of a glycoprotein. This study describes two newly discovered proteins that form the glue-glycoprotein of the golden orb weaving spider Nephila clavipes . Our results demonstrate that both proteins contain unique 110 amino acid repetitive domains that are encoded by opposite strands of the same DNA sequence. Thus, the genome of the spider encodes two distinct yet functionally related genes by using both strands of an identical DNA sequence. Moreover, the closest match for the nonrepetitive region of one of the proteins is chitin binding proteins. The web glue appears to have evolved a substantial level of sophistication matching that of the spider silk fibers.

  15. A Simple ``Sticky Disc'' Model for Crystalline and Amorphous Networks

    NASA Astrophysics Data System (ADS)

    Huerta, Adrian; Chubynsky, Nikita; Naumis, Gerardo; Thorpe, Michael

    2005-03-01

    Using Monte Carlo simulations, we study the structural and thermodynamic behavior of a simple one component network forming model made up of ``sticky discs.'' Central and bond bending forces was included, modeling such interactions as a simple square well radial and angular three body term in the potential respectively. The main feature of this model is the ability to form crystalline and amorphous networks upon cooling, similar to that obtained using the so called WWW methodology to describe the network of some vitreous structures [1]. With the ``pebble game'' algorithm [2], we evaluate the number of degrees of freedom and the amount of stress in both the amorphous and crystalline structures. We discuss the connection between the configurational entropy (associated with the topology) and the degrees of freedom. Other effects such as elasticity of these structures are also discussed. 1. Wooten, F., Winer, K. and Weaire, D., Phys. Rev. Lett., 54 1392- 1395 (1985). 2. Jacobs, D.J. and Thorpe, M.F., Phys. Rev. Lett., 75 4051- 4054 (1995).

  16. A fundamental measure theory for the sticky hard sphere fluid.

    PubMed

    Hansen-Goos, Hendrik; Wettlaufer, J S

    2011-01-07

    We construct a density functional theory (DFT) for the sticky hard sphere (SHS) fluid which, like Rosenfeld's fundamental measure theory (FMT) for the hard sphere fluid [Y. Rosenfeld, Phys. Rev. Lett. 63, 980 (1989)], is based on a set of weighted densities and an exact result from scaled particle theory (SPT). It is demonstrated that the excess free energy density of the inhomogeneous SHS fluid Φ(SHS) is uniquely defined when (a) it is solely a function of the weighted densities from Kierlik and Rosinberg's version of FMT [E. Kierlik and M. L. Rosinberg, Phys. Rev. A 42, 3382 (1990)], (b) it satisfies the SPT differential equation, and (c) it yields any given direct correlation function (DCF) from the class of generalized Percus-Yevick closures introduced by Gazzillo and Giacometti [J. Chem. Phys. 120, 4742 (2004)]. The resulting DFT is shown to be in very good agreement with simulation data. In particular, this FMT yields the correct contact value of the density profiles with no adjustable parameters. Rather than requiring higher order DCFs, such as perturbative DFTs, our SHS FMT produces them. Interestingly, although equivalent to Kierlik and Rosinberg's FMT in the case of hard spheres, the set of weighted densities used for Rosenfeld's original FMT is insufficient for constructing a DFT which yields the SHS DCF.

  17. Facebook Influence among Incoming College Freshmen: Sticky Cues and Alcohol

    PubMed Central

    D’Angelo, Jonathan; Zhang, Chong; Eickhoff, Jens; Moreno, Megan

    2014-01-01

    Alcohol displays on Facebook are ever-present and can be socially desirable for college students. As problematic drinking is a concern for college students, this research sought to understand how different types of information on a Facebook page influence likelihood to drink. Telephone interviews were conducted with 338 incoming college freshmen from two large national universities. Data were obtained from a vignette prompt which presented a scenario in which a senior college student’s Facebook profile displayed wall-posts, pictures, and status updates that were drinking-related or pro-social in nature. Participants were asked to report intention to drink alcohol with that student if together at a party. Findings supported the hypotheses: wall-posts were most influential (the stickiest), followed by pictures, followed by status updates. Findings provide additional empirical support for established online impression formation patterns, and additionally provide evidence that virtual cues are being ingrained as schema in interpersonal communication. These results are discussed in relation to the conception of “sticky cues” in impression formation. PMID:25328264

  18. An orb-weaver spider exploits an ant–acacia mutualism for enemy-free space

    PubMed Central

    Styrsky, John D

    2014-01-01

    Exploiters of protection mutualisms are assumed to represent an important threat for the stability of those mutualisms, but empirical evidence for the commonness or relevance of exploiters is limited. Here, I describe results from a manipulative study showing that an orb-weaver spider, Eustala oblonga, inhabits an ant-acacia for protection from predators. This spider is unique in the orb-weaver family in that it associates closely with both a specific host plant and ants. I tested the protective effect of acacia ants on E. oblonga by comparing spider abundance over time on acacias with ants and on acacias from which entire ant colonies were experimentally removed. Both juvenile and adult spider abundance significantly decreased over time on acacias without ants. Concomitantly, the combined abundance of potential spider predators increased over time on acacias without ants. These results suggest that ant protection of the ant-acacia Acacia melanocerus also protects the spiders, thus supporting the hypothesis that E. oblonga exploits the ant–acacia mutualism for enemy-free space. Although E. oblonga takes advantage of the protection services of ants, it likely exacts little to no cost and should not threaten the stability of the ant–acacia mutualism. Indeed, the potential threat of exploiter species to protection mutualisms in general may be limited to species that exploit the material rewards traded in such mutualisms rather than the protection services. PMID:24558583

  19. Colourful orb-weaving spiders, Nephila pilipes, through a bee's eyes.

    PubMed

    Tso, I-Min; Lin, Chih-Wei; Yang, En-Cheng

    2004-07-01

    Many orb-weaving spiders in the tropics forage in open sites during the day and some of them have both bright and dark colourations. The conspicuous UV-reflective colour markings of these spiders have been reported to be attractive to visually oriented prey and thus could increase the spiders' foraging success. Using a combination of field and laboratory studies, we examine whether or not the body colouration of orb-weaving spiders exhibits optical properties that are attractive to insect prey from the viewpoint of insect visual physiology. We compared the prey interception rates and colour contrasts of the typical and melanic morphs of the giant wood spider, Nephila pilipes. Results of the field study showed that the typical morph caught significantly more insects than the melanic morph. Colour contrasts calculated from spectral reflectances of the background and body surface of spiders showed that the brightly coloured body parts of the typical morph exhibited rather high values, but those of the dark body parts were below the discrimination threshold. The differential colour contrasts of body parts generated a visual signal unlike that of a spider but rather like certain forms of food resources. On the other hand, the melanic morphs did not have bright colouration and the colour contrasts of every part of the body were significantly higher than the threshold, making the contour of spiders quite clear to bees.

  20. THE STICKINESS OF MICROMETER-SIZED WATER-ICE PARTICLES

    SciTech Connect

    Gundlach, B.; Blum, J.

    2015-01-01

    Water ice is one of the most abundant materials in dense molecular clouds and in the outer reaches of protoplanetary disks. In contrast to other materials (e.g., silicates), water ice is assumed to be stickier due to its higher specific surface energy, leading to faster or more efficient growth in mutual collisions. However, experiments investigating the stickiness of water ice have been scarce, particularly in the astrophysically relevant micrometer-sized region and at low temperatures. In this work, we present an experimental setup to grow aggregates composed of μm-sized water-ice particles, which we used to measure the sticking and erosion thresholds of the ice particles at different temperatures between 114 K and 260 K. We show with our experiments that for low temperatures (below ∼210 K), μm-sized water-ice particles stick below a threshold velocity of 9.6 m s{sup –1}, which is approximately 10 times higher than the sticking threshold of μm-sized silica particles. Furthermore, erosion of the grown ice aggregates is observed for velocities above 15.3 m s{sup –1}. A comparison of the experimentally derived sticking threshold with model predictions is performed to determine important material properties of water ice, i.e., the specific surface energy and the viscous relaxation time. Our experimental results indicate that the presence of water ice in the outer reaches of protoplanetary disks can enhance the growth of planetesimals by direct sticking of particles.

  1. Local acting Sticky-trap inhibits vascular endothelial growth factor dependent pathological angiogenesis in the eye

    PubMed Central

    Michael, Iacovos P; Westenskow, Peter D; Hacibekiroglu, Sabiha; Greenwald, Alissa Cohen; Ballios, Brian G; Kurihara, Toshihide; Li, Zhijie; Warren, Carmen M; Zhang, Puzheng; Aguilar, Edith; Donaldson, Laura; Marchetti, Valentina; Baba, Takeshi; Hussein, Samer M; Sung, Hoon-Ki; Iruela-Arispe, M Luisa; Rini, James M; van der Kooy, Derek; Friedlander, Martin; Nagy, Andras

    2014-01-01

    Current therapeutic antiangiogenic biologics used for the treatment of pathological ocular angiogenesis could have serious side effects due to their interference with normal blood vessel physiology. Here, we report the generation of novel antivascular endothelial growth factor-A (VEGF) biologics, termed VEGF “Sticky-traps,” with unique properties that allow for local inhibition of angiogenesis without detectable systemic side effects. Using genetic and pharmacological approaches, we demonstrated that Sticky-traps could locally inhibit angiogenesis to at least the same extent as the original VEGF-trap that also gains whole-body access. Sticky-traps did not cause systemic effects, as shown by uncompromised wound healing and normal tracheal vessel density. Moreover, if injected intravitreally, recombinant Sticky-trap remained localized to various regions of the eye, such as the inner-limiting membrane and ciliary body, for prolonged time periods, without gaining access either to the photoreceptors/choriocapillaris area or the circulation. These unique pharmacological characteristics of Sticky-trap could allow for safe treatment of pathological angiogenesis in patients with diabetic retinopathy and retinopathy of pre-maturity. PMID:24705878

  2. Formaldehyde-induced acentric chromosome fragments and chromosome stickiness in Chortophaga neuroblasts

    SciTech Connect

    Dowd, M.A.; Gaulden, M.E.; Proctor, B.L.; Seibert, G.B.

    1986-01-01

    Embryos of the grasshopper Chortophaga viridifasciata were exposed in vitro to formaldehyde (FA), as formalin, at concentrations ranging from 10/sup -8/ M (0.0003 ppm) to 10/sup -3/ M (30 ppm) at 38/sup 0/C. A low frequency of distinct acentric chromosome fragments was observed in the neuroblasts after 1 hr exposure to 7.5 x 10/sup -4/ or 10/sup -3/ M FA plus 3 hr recovery, but not at lower concentrations, even with 4 hr exposure. Neuroblasts with sticky chromosomes were observed at 10/sup -4/, 7.5 x 10/sup -4/, and 10/sup -3/ M FA, the percent of cells with slight, moderate, or severe stickiness varying with FA concentrations. Fragments were associated with the sticky chromosomes. It is concluded that the distinct acentric fragments induced by FA result from breakage at a single sticky point (slight stickiness) between separating sister chromatids. The chromosome effects observed probably result from the action of daughter products that are formed by the interaction of FA with culture medium components, especially the fetal calf serum.

  3. Structure-activity relationships of pyrrolizidine alkaloids in insect chemical defense against the orb-weaving spider Nephila clavipes.

    PubMed

    Silva, Karina Lucas; Trigo, José Roberto

    2002-04-01

    Pyrrolizidine alkaloids (PAs) are known to protect Arctiidae moths and Danainae and Ithomiinae butterflies against the orb-weaving spider Nephila clavipes (Araneae, Araneidae, Tetragnathinae), which liberates adults of these insects unharmed from its web. We tested against this spider the role of eight PAs and one derived structure [an 89:11 mixture of the 12-membered macrocyclic diester free base integerrimine and senecionine and the respective N-oxide; two hydrolysis products from this mixture (the necine base retronecine, its respective N-oxide, and a mixture of integerriminic and senecionic necic acids); the 12-membered macrocyclic senkirkine; the 9-O-monoester free base senecioylretronecine and its respective N-oxide; and the 9-O-monoester free base callimorphine (a PA biosynthesized only by insects from retronecine)]. The mixture integerrimine-senecionine N-oxide seems to be more active than the respective free base [LibD50 (liberation dose 50) = 0.042 and 0.153 microg/dry weight of prey, respectively], but the difference in activity between the N-oxide and free base of the 9-O-monoester senecioylretronecine was slight (LibD50 = 0.167 and 0.104, respectively). Senkirkine, an otonecine base PA that does not form N-oxide and is not found in insects, was the less active, showing the highest LibD50 (0.354). The difference in antipredator activity between N-oxides and free bases from macrocyclic diesters and monoesters may be correlated with physicochemical properties of these molecules in interaction with the Nephila receptors. For the active structures, there was a significant correlation between dosage and antipredator activity. Both forms of retronecine and a necic acid mixture were inactive, supporting the hypothesis that PAs biosynthesized by insects from retronecine were originally produced and stored in order to optimize chemical defense. Comparison of dose/activity data with reported amounts of PAs in butterflies suggested that, in general, PA

  4. A New Stratified Sampling Procedure which Decreases Error Estimation of Varroa Mite Number on Sticky Boards.

    PubMed

    Kretzschmar, A; Durand, E; Maisonnasse, A; Vallon, J; Le Conte, Y

    2015-06-01

    A new procedure of stratified sampling is proposed in order to establish an accurate estimation of Varroa destructor populations on sticky bottom boards of the hive. It is based on the spatial sampling theory that recommends using regular grid stratification in the case of spatially structured process. The distribution of varroa mites on sticky board being observed as spatially structured, we designed a sampling scheme based on a regular grid with circles centered on each grid element. This new procedure is then compared with a former method using partially random sampling. Relative error improvements are exposed on the basis of a large sample of simulated sticky boards (n=20,000) which provides a complete range of spatial structures, from a random structure to a highly frame driven structure. The improvement of varroa mite number estimation is then measured by the percentage of counts with an error greater than a given level.

  5. When sticky fluids don't stick: yield-stress fluid drops on heated surfaces

    NASA Astrophysics Data System (ADS)

    Blackwell, Brendan; Wu, Alex; Ewoldt, Randy

    2016-11-01

    Yield-stress fluids, including gels and pastes, are effectively fluid at high stress and solid at low stress. In liquid-solid impacts, these fluids can stick and accumulate where they impact; this sticky behavior motivates several applications of these rheologically-complex materials. Here we describe experiments with aqueous yield stress fluids that are more 'sticky' than water at room temperature (e.g. supporting larger coating thicknesses), but are less 'sticky' at higher temperatures. Specifically, we study the conditions for aqueous yield stress fluids to bounce and slide on heated surfaces when water sticks. Here we present high-speed imaging and color interferometry to observe the thickness of the vapor layer between the drop and the surface during both stick and non-stick events. We use these data to gain insight into the physics behind the phenomenon of the yield-stress fluids bouncing and sliding, rather than sticking, on hot surfaces.

  6. Chromosome stickiness impairs meiosis and influences reproductive success in Panicum maximum (Poaceae) hybrid plants.

    PubMed

    Pessim, C; Pagliarini, M S; Silva, N; Jank, L

    2015-04-28

    Chromosome stickiness has been studied in several species of higher plants and is characterized by sticky clumps of chromatin resulting in sterility. Chromosome stickiness was recorded in Panicum maximum hybrid plants that were cultivated in the field. In the meiocytes affected, chromosomes clumped into amorphous masses that did not orient themselves on the equatorial plate, and anaphase I disjunction failed to occur. After a normal cytokinesis, the masses of chromatin were divided between both daughter cells. Metaphase and anaphase of the second division also did not occur, and after the second cytokinesis, polyads were formed. This abnormality arose spontaneously. Abnormalities that cause male sterility are an important tool for obtaining hybrid seeds in plant breeding. This is the first report of an abnormality affecting pollen viability in P. maximum. This finding can open a new opportunity in the breeding program of this species that is devoted to hybridization where manual cross-pollination is difficult and time consuming.

  7. Biomechanical variation of silk links spinning plasticity to spider web function.

    PubMed

    Boutry, Cecilia; Blackledge, Todd A

    2009-01-01

    Spider silk is renowned for its high tensile strength, extensibility and toughness. However, the variability of these material properties has largely been ignored, especially at the intra-specific level. Yet, this variation could help us understand the function of spider webs. It may also point to the mechanisms used by spiders to control their silk production, which could be exploited to expand the potential range of applications for silk. In this study, we focus on variation of silk properties within different regions of cobwebs spun by the common house spider, Achaearanea tepidariorum. The cobweb is composed of supporting threads that function to maintain the web shape and hold spiders and prey, and of sticky gumfooted threads that adhere to insects during prey capture. Overall, structural properties, especially thread diameter, are more variable than intrinsic material properties, which may reflect past directional selection on certain silk performance. Supporting threads are thicker and able to bear higher loads, both before deforming permanently and before breaking, compared with sticky gumfooted threads. This may facilitate the function of supporting threads through sustained periods of time. In contrast, sticky gumfooted threads are more elastic, which may reduce the forces that prey apply to webs and allow them to contact multiple sticky capture threads. Therefore, our study suggests that spiders actively modify silk material properties during spinning in ways that enhance web function.

  8. The Knight Stick Trap and Knight Stick Sticky Wraps: New Tools for Stable Fly (Diptera: Muscidae) Management.

    PubMed

    Hogsette, Jerome A; Kline, Daniel L

    2017-03-20

    Stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), management can be difficult, especially in situations where pesticide usage is restricted or disallowed. Traps have been used for monitoring stable flies, but have rarely been used for management. The Knight Stick (KS) trap recently became available, and preliminary studies indicated that it might be an improvement to traps currently in use. The Olson Sticky Fly trap was chosen as the control trap for the purpose of comparisons. Both traps attract stable flies by alteration of light waves and capture flies on a sticky wrap covering the trap base. The KS trap captured 3× more stable flies than the Olson trap, whereas the Olson trap base covered with the KS Sticky wrap captured 3-5× more stable flies than the Olson trap base with the standard Olson Sticky wrap. This indicated inherent attraction from the KS Sticky wrap. This was supported when KS Tank wraps, a larger version of the KS Sticky wraps, applied to 51 kg of liquid propane (LP) tanks on Mosquito Magnet Independence traps producing CO2, captured significantly more stable flies and significantly more stable flies per square centimeter of sticky wrap than Olson Sticky Sleeve wraps applied to the LP tanks. In a final study, when two configurations of KS Tank wraps were applied to white plastic barrels and compared with three standard KS traps, mean numbers of stable flies captured were numerically similar. The significance of findings and potential uses for the traps are discussed.

  9. Comparisons of minicard ratings to ion chromatography sugar profiles in cotton fiber water extract and minicard sticky spot material

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Specific levels and ratios of the carbohydrates melezitose and trehalulose deposited on the surface of cotton fibers are indicators of whitefly or aphid contamination. These deposits could cause stickiness problems during cotton ginning and textile processing. The concept of cotton stickiness is hi...

  10. Roles of water and solids composition in the control of glass transition and stickiness of milk powders.

    PubMed

    Silalai, Nattiga; Roos, Yrjö H

    2010-06-01

    Plasticization and glass transition of amorphous components in food powders often result in stickiness and caking. The glass transition temperature (T(g)) of milk powders was measured by differential scanning calorimetry (DSC) and a viscometer method was used to determine sticky-point temperatures. Water sorption isotherms were established for varying solids compositions. Lactose contents were analyzed by high-performance anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) and proteins were identified using SDS-PAGE gel electrophoresis. Solids composition and water affected both the T(g) and stickiness behavior. Stickiness was governed by carbohydrates and water plasticization. At low protein contents, precrystallization of lactose decreased the sticky point temperature, but increasing protein content in all milk powders decreased stickiness at all water activities. The results showed that glass transition can be used to describe time-dependent stickiness and crystallization phenomena, and it can be used as a parameter to control and reduce stickiness of dairy solids with various compositions.

  11. Spider web-inspired acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Miniaci, Marco; Krushynska, Anastasiia; Movchan, Alexander B.; Bosia, Federico; Pugno, Nicola M.

    2016-08-01

    Spider silk is a remarkable example of bio-material with superior mechanical characteristics. Its multilevel structural organization of dragline and viscid silk leads to unusual and tunable properties, extensively studied from a quasi-static point of view. In this study, inspired by the Nephila spider orb web architecture, we propose a design for mechanical metamaterials based on its periodic repetition. We demonstrate that spider-web metamaterial structure plays an important role in the dynamic response and wave attenuation mechanisms. The capability of the resulting structure to inhibit elastic wave propagation in sub-wavelength frequency ranges is assessed, and parametric studies are performed to derive optimal configurations and constituent mechanical properties. The results show promise for the design of innovative lightweight structures for tunable vibration damping and impact protection, or the protection of large scale infrastructure such as suspended bridges.

  12. Small colony variant of methicillin-resistant Staphylococcus pseudintermedius ST71 presenting as a sticky phenotype.

    PubMed

    Savini, Vincenzo; Carretto, Edoardo; Polilli, Ennio; Marrollo, Roberta; Santarone, Stella; Fazii, Paolo; D'Antonio, Domenico; Rossano, Alexandra; Perreten, Vincent

    2014-04-01

    We first observed the phenomenon of small colony variants (SCVs) in a Staphylococcus pseudintermedius sequence type 71 (ST71) strain, isolated from a non-pet owner. Although we found that small-sized colonies share main features with Staphylococcus aureus SCVs, they nevertheless show a novel, particular, and sticky phenotype, whose expression was extremely stable, even after subcultivation.

  13. A comparison of sticky traps for monitoring Asian citrus psyllid (Diaphorina citri Kuwayama)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Six types of sticky card traps differing in color and trapping adhesive were evaluated for monitoring Asian citrus psyllid in citrus in the United States (Florida and Texas). Spectral reflectance measurements were taken to categorize the color (wavelength) spectrum of each trap. Three of the traps (...

  14. Basal characteristics of the main sticky spot in the ice plain of Whillans Ice Stream

    NASA Astrophysics Data System (ADS)

    Luthra, Tarun; Anandakrishnan, Sridhar; Alley, Richard; Winberry, Paul

    2015-04-01

    Understanding the processes that affect streaming ice flow and the mass balance of glaciers and ice sheets requires sound knowledge of the subglacial environment. Areas of high basal drag along ice streams and glaciers, termed sticky spots, are of particular interest because they inhibit the fast flow of the overriding ice and can act to redirect subglacial water flow. Whillans Ice Stream (WIS), along the Siple Coast of the West Antarctic Ice Sheet, conducts diurnal stick slip motion, largely due to a sticky spot within the main trunk of the ice stream. Previous studies have shown evidence of continuous deformable subglacial sediment presence, which is a prerequisite for fast ice stream flow. We present results from a seismic reflection experiment performed along the flow of the WIS sticky spot to image the subglacial setting related to this basal feature and elucidate its role in ice dynamics. Our results show a presence of a laterally continuous 6 m thick basal till, having P wave velocities of greater than > 1800 m/s and densities upwards of 1900 kg/m3 indicative of a stiff till suggesting the underlying bed is stronger than the overflowing ice, causing drag to the ice stream flow and possibly the main cause of the sticky spot.

  15. A Sticky Stick? The Locus of Morphological Representation in the Lexicon

    ERIC Educational Resources Information Center

    Taft, Marcus; Nguyen-Hoan, Minh

    2010-01-01

    It is demonstrated that the meaning given to an ambiguous word (e.g., "stick") can be biased by the masked presentation of a polymorphemic word derived from that meaning (e.g., "sticky"). No bias in interpretation is observed when the masked prime is a word that is semantically related to the target with no morphological…

  16. Commercial yellow sticky strips more attractive than yellow boards to western cherry fruit fly (Dipt., Tephritidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bright yellow sticky rectangles made of paper boards were previously identified as the most effective traps for capturing western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae). Thin rectangular sheets of yellow plastic allow higher light passage than yellow boards and may b...

  17. Science 101: Why Don't Spiders Stick to Their Own Webs?

    ERIC Educational Resources Information Center

    Robertson, Bill

    2011-01-01

    This article explains why spiders don't stick to their webs. Spiders don't get stuck in their own webs (and they aren't immune to their own glue) because they use a combination of sticky and nonsticky threads (different glands for producing those), and the glue is in droplets that the spider can avoid but the prey can't. The spider's nervous…

  18. Web Formation - Skylab Student Experiment ED-52

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Judith S. Miles of Lexington High School, Lexington, Massachusetts, proposed skylab student experiment ED-52, Web Formation. This experiment was a study of a spider's behavior in a weightless environment. The geometrical structure of the web of the orb-weaving spider provides a good measure of the condition of its central nervous system. Since the spider senses its own weight to determine the required thickness of web material and uses both the wind and gravity to initiate construction of its web, the lack of gravitational force in Skylab provided a new and different stimulus to the spider's behavioral response. Two common cross spiders, Arabella and Anita, were used for the experiment aboard the Skylab-3 mission. After initial disoriented attempts, both spiders produced almost Earth-like webs once they had adapted to weightlessness. This photograph is of Arabella, a cross spider, in her initial attempt at spirning a web. This picture was taken by the crew of the Skylab 3 mission before Arabella adapted to her new environment.

  19. Study of sticky rice-lime mortar technology for the restoration of historical masonry construction.

    PubMed

    Yang, Fuwei; Zhang, Bingjian; Ma, Qinglin

    2010-06-15

    Replacing or repairing masonry mortar is usually necessary in the restoration of historical constructions, but the selection of a proper mortar is often problematic. An inappropriate choice can lead to failure of the restoration work, and perhaps even further damage. Thus, a thorough understanding of the original mortar technology and the fabrication of appropriate replacement materials are important research goals. Many kinds of materials have been used over the years in masonry mortars, and the technology has gradually evolved from the single-component mortar of ancient times to hybrid versions containing several ingredients. Beginning in 2450 BCE, lime was used as masonry mortar in Europe. In the Roman era, ground volcanic ash, brick powder, and ceramic chip were added to lime mortar, greatly improving performance. Because of its superior properties, the use of this hydraulic (that is, capable of setting underwater) mortar spread, and it was adopted throughout Europe and western Asia. Perhaps because of the absence of natural materials such as volcanic ash, hydraulic mortar technology was not developed in ancient China. However, a special inorganic-organic composite building material, sticky rice-lime mortar, was developed. This technology was extensively used in important buildings, such as tombs, in urban constructions, and even in water conservancy facilities. It may be the first widespread inorganic-organic composite mortar technology in China, or even in the world. In this Account, we discuss the origins, analysis, performance, and utility in historic preservation of sticky rice-lime mortar. Mortar samples from ancient constructions were analyzed by both chemical methods (including the iodine starch test and the acid attack experiment) and instrumental methods (including thermogravimetric differential scanning calorimetry, X-ray diffraction, Fourier transform infrared, and scanning electron microscopy). These analytical results show that the ancient masonry

  20. ORBS, ORCS, OACS, a Software Suite for Data Reduction and Analysis of the Hyperspectral Imagers SITELLE and SpIOMM

    NASA Astrophysics Data System (ADS)

    Martin, T.; Drissen, L.; Joncas, G.

    2015-09-01

    SITELLE (installed in 2015 at the Canada-France-Hawaii Telescope) and SpIOMM (a prototype attached to the Observatoire du Mont-Mégantic) are the first Imaging Fourier Transform Spectrometers (IFTS) capable of obtaining a hyperspectral data cube which samples a 12 arc minutes field of view into four millions of visible spectra. The result of each observation is made up of two interferometric data cubes which need to be merged, corrected, transformed and calibrated in order to get a spectral cube of the observed region ready to be analysed. ORBS is a fully automatic data reduction software that has been entirely designed for this purpose. The data size (up to 68 Gb for larger science cases) and the computational needs have been challenging and the highly parallelized object-oriented architecture of ORBS reflects the solutions adopted which made possible to process 68 Gb of raw data in less than 11 hours using 8 cores and 22.6 Gb of RAM. It is based on a core framework (ORB) that has been designed to support the whole software suite for data analysis (ORCS and OACS), data simulation (ORUS) and data acquisition (IRIS). They all aim to provide a strong basis for the creation and development of specialized analysis modules that could benefit the scientific community working with SITELLE and SpIOMM.

  1. Biogeography and speciation patterns of the golden orb spider genus Nephila (Araneae: Nephilidae) in Asia.

    PubMed

    Su, Yong-Chao; Chang, Yung-Hau; Smith, Deborah; Zhu, Ming-Sheng; Kuntner, Matjaž; Tso, I-Min

    2011-01-01

    The molecular phylogeny of the globally distributed golden orb spider genus Nephila (Nephilidae) was reconstructed to infer its speciation history, with a focus on SE Asian/W Pacific species. Five Asian, two Australian, four African, and one American species were included in the phylogenetic analyses. Other species in Nephilidae, Araneidae, and Tetragnathidae were included to assess their relationships with the genus Nephila, and one species from Uloboridae was used as the outgroup. Phylogenetic trees were reconstructed from one nuclear (18S) and two mitochondrial (COI and 16S) markers. Our molecular phylogeny shows that the widely distributed Asian/Australian species, N. pilipes, and an African species, N. constricta, form a clade that is sister to all other Nephila species. Nested in this Nephila clade are one clade with tropical and subtropical/temperate Asian/Australian species, and the other containing African and American species. The estimated divergence times suggest that diversification events within Nephila occurred during mid-Miocene to Pliocene (16 Mya-2 Mya), and these time periods were characterized by cyclic global warming/cooling events. According to Dispersal and Vicariance Analysis (DIVA), the ancestral range of the Asian/Australian clade was tropical Asia, and the ancestral range of the genus Nephila was either tropical Asia or Africa. We conclude that the speciation of the Asian/Australian Nephila species was driven by Neogene global cyclic climate changes. However, further population level studies comparing diversification patterns of sister species are needed to determine the mode of speciation of these species.

  2. Fighting for the web: competition between female feather-legged spiders (Uloborus plumipes).

    PubMed

    Joel, Anna-Christin; Habedank, Anne; Hausen, Jonas; Mey, Jörg

    2017-04-01

    Most spider species are solitary, and among the few social interactions among them, resource competition between females has received little attention. We discovered that females of the feather-legged spider Uloborus plumipes invade the orb webs of conspecifics and compete for webs. Following observations in the wild, intruder-defender interactions were studied in a terrarium and in controlled laboratory experiments. We found that contests for orb webs occurred spontaneously between adult females. Competitive interactions in U. plumipes were characterized by an escalation of ritualized behaviors. In 27% of the contests the winner was determined by interactions at a distance, which involved behaviors that caused vibratory signaling on the web. The remaining interactions escalated to physical contact, and in 78% of these a fight occurred between the contestants. Using multivariate logistic regression we determined the factors that predicted the outcome of the contests: (i) Web ownership did not give the defender a competitive advantage. (ii) The difference in physical size between the competing spiders was the most important predictor for the outcome of web contests. (iii) Independent of body size, the display of certain behaviors, specifically the ability to reach the hub before the contestant and the frequency of attacks, increased the probability of winning. (iv) Winning or losing a fight did not affect the chances of winning subsequent contests. The interactions reported here provide a promising approach to investigate communication in spiders and to test theoretical models of intraspecific competition.

  3. Web Formation - Skylab Student Experiment ED-52

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This chart describes the Skylab student experiment Web Formation. Judith S. Miles of Lexington High School, Lexington, Massachusetts, proposed a study of the spider's behavior in a weightless environment. The geometrical structure of the web of the orb-weaving spider provides a good measure of the condition of its central nervous system. Since the spider senses its own weight to determine the required thickness of web material and uses both the wind and gravity to initiate construction of its web, the lack of gravitational force in Skylab provided a new and different stimulus to the spider's behavioral response. Two common cross spiders, Arabella and Anita, were used for the experiment aboard the Skylab-3 mission. After initial disoriented attempts, both spiders produced almost Earth-like webs once they had adapted to weightlessness. In March 1972, NASA and the National Science Teachers Association selected 25 experiment proposals for flight on Skylab. Science advisors from the Marshall Space Flight Center aided and assisted the students in developing the proposals for flight on Skylab.

  4. Selection of colour of sticky trap for monitoring adult bean thrips, Caliothrips fasciatus (Thysanoptera: Thripidae).

    PubMed

    Harman, J Alex; Mao, Chang Xuan; Morse, Joseph G

    2007-02-01

    Adult bean thrips, Caliothrips fasciatus (Pergande), overwintering inside the navel of navel oranges shipped from California to Australia, are an actionable pest for the importing country, i.e. infested lots are fumigated with methyl bromide. Strict quarantine regulations regarding C. fasciatus prompted studies on the best colour sticky trap that might be used to monitor for bean thrips populations in the vicinity of California citrus groves prior to harvesting fruit for export. Preliminary experiments identified the most attractive trap of each of four colours (blue, green, white, yellow) commonly used to sample adult Thysanoptera. Three trials of a field study were conducted, comparing C. fasciatus capture on the best card of each colour using asparagus ferns naturally infested with high levels of this pest. Based on significantly higher catch on green sticky cards, this colour trap is recommended for potential use in California's bean thrips mitigation plan designed to reduce thrips levels on citrus exported to Australia.

  5. Equation of state of sticky-hard-sphere fluids in the chemical-potential route.

    PubMed

    Rohrmann, René D; Santos, Andrés

    2014-04-01

    The coupling-parameter method, whereby an extra particle is progressively coupled to the rest of the particles, is applied to the sticky-hard-sphere fluid to obtain its equation of state in the so-called chemical-potential route (μ route). As a consistency test, the results for one-dimensional sticky particles are shown to be exact. Results corresponding to the three-dimensional case (Baxter's model) are derived within the Percus-Yevick approximation by using different prescriptions for the dependence of the interaction potential of the extra particle on the coupling parameter. The critical point and the coexistence curve of the gas-liquid phase transition are obtained in the μ route and compared with predictions from other thermodynamics routes and from computer simulations. The results show that the μ route yields a general better description than the virial, energy, compressibility, and zero-separation routes.

  6. The role of perceived interactivity in virtual communities: building trust and increasing stickiness

    NASA Astrophysics Data System (ADS)

    Wang, Hongwei; Meng, Yuan; Wang, Wei

    2013-03-01

    Although previous research has explored factors affecting trust building in websites, little research has been analysed from the perceived interactivity perspective in virtual communities (VCs). A research model for verifying interactivity antecedents to trust and its impact on member stickiness behaviour is presented. Two social interactivity components and two system interactivity components are, respectively, theorised as process-based antecedents and institution-based antecedents to trust in the model. Data were collected from 310 members of VCs to test the model. The results show that connectedness and reciprocity are important antecedents to trust in members, while responsiveness and active control are important antecedents to trust in systems. The results also indicate that trust has significant influence on the members' duration and retention, which are two dimensions of member stickiness measured in this research. These findings have theoretical implications for online interaction-related literature and critical business implications for practitioners of VCs.

  7. [Livedoid vasculopathy with heterozygous factor V Leiden mutation and sticky platelet syndrome].

    PubMed

    Lewerenz, V; Burchardt, T; Büchau, A; Ruzicka, T; Megahed, M

    2004-04-01

    A 64-year-old male patient presented with painful ulcerations and livedo racemosa of both lower limbs. He had a history of cerebral and myocardial infarctions. Dermatohistologic findings and laboratory tests of the patient's coagulation system revealed the diagnosis of livedoid vasculopathy with heterozygous factor V Leiden mutation and sticky platelet syndrome type II. Systemic treatment with acetylsalicylic acid and heparin as well as topical therapy with disinfectant and granulation-inducing agents resulted in improvement of the skin lesions.

  8. The molecular structural features controlling stickiness in cooked rice, a major palatability determinant.

    PubMed

    Li, Hongyan; Fitzgerald, Melissa A; Prakash, Sangeeta; Nicholson, Timothy M; Gilbert, Robert G

    2017-03-06

    The stickiness of cooked rice is important for eating quality and consumer acceptance. The first molecular understanding of stickiness is obtained from leaching and molecular structural characteristics during cooking. Starch is a highly branched glucose polymer. We find (i) the molecular size of leached amylopectin is 30 times smaller than that of native amylopectin while (ii) that of leached amylose is 5 times smaller than that of native amylose, (iii) the chain-length distribution (CLD: the number of monomer units in a chain on the branched polymer) of leached amylopectin is similar to native amylopectin while (iv) the CLD of leached amylose is much narrower than that of the native amylose, and (v) mainly amylopectin, not amylose, leaches out of the granule and rice kernel during cooking. Stickiness is found to increase with decreasing amylose content in the whole grain, and, in the leachate, with increasing total amount of amylopectin, the proportion of short amylopectin chains, and amylopectin molecular size. Molecular adhesion mechanisms are put forward to explain this result. This molecular structural mechanism provides a new tool for rice breeders to select cultivars with desirable palatability by quantifying the components and molecular structure of leached starch.

  9. The molecular structural features controlling stickiness in cooked rice, a major palatability determinant

    PubMed Central

    Li, Hongyan; Fitzgerald, Melissa A.; Prakash, Sangeeta; Nicholson, Timothy M.; Gilbert, Robert G.

    2017-01-01

    The stickiness of cooked rice is important for eating quality and consumer acceptance. The first molecular understanding of stickiness is obtained from leaching and molecular structural characteristics during cooking. Starch is a highly branched glucose polymer. We find (i) the molecular size of leached amylopectin is 30 times smaller than that of native amylopectin while (ii) that of leached amylose is 5 times smaller than that of native amylose, (iii) the chain-length distribution (CLD: the number of monomer units in a chain on the branched polymer) of leached amylopectin is similar to native amylopectin while (iv) the CLD of leached amylose is much narrower than that of the native amylose, and (v) mainly amylopectin, not amylose, leaches out of the granule and rice kernel during cooking. Stickiness is found to increase with decreasing amylose content in the whole grain, and, in the leachate, with increasing total amount of amylopectin, the proportion of short amylopectin chains, and amylopectin molecular size. Molecular adhesion mechanisms are put forward to explain this result. This molecular structural mechanism provides a new tool for rice breeders to select cultivars with desirable palatability by quantifying the components and molecular structure of leached starch. PMID:28262830

  10. Single-Molecule Imaging of DNAs with Sticky Ends at Water/Fused Silica Interface

    SciTech Connect

    Isailovic, Slavica

    2005-01-01

    Total internal reflection fluorescence microscopy (TIRFM) was used to study intermolecular interactions of DNAs with unpaired (sticky) ends of different lengths at water/fused silica interface at the single-molecule level. Evanescent field residence time, linear velocity and adsorption/desorption frequency were measured in a microchannel for individual DNA molecules from T7, Lambda, and PSP3 phages at various pH values. The longest residence times and the highest adsorption/desorption frequencies at the constant flow at pH 5.5 were found for PSP3 DNA, followed by lower values for Lambda DNA, and the lowest values for T7 DNA. Since T7, Lambda, and PSP3 DNA molecules contain none, twelve and nineteen unpaired bases, respectively, it was concluded that the affinity of DNAs for the surface increases with the length of the sticky ends. This confirms that hydrophobic and hydrogen-bonding interactions between sticky ends and fused-silica surface are driving forces for DNA adsorption at the fused-silica surface. Described single-molecule methodology and results therein can be valuable for investigation of interactions in liquid chromatography, as well as for design of DNA hybridization sensors and drug delivery systems.

  11. The molecular structural features controlling stickiness in cooked rice, a major palatability determinant

    NASA Astrophysics Data System (ADS)

    Li, Hongyan; Fitzgerald, Melissa A.; Prakash, Sangeeta; Nicholson, Timothy M.; Gilbert, Robert G.

    2017-03-01

    The stickiness of cooked rice is important for eating quality and consumer acceptance. The first molecular understanding of stickiness is obtained from leaching and molecular structural characteristics during cooking. Starch is a highly branched glucose polymer. We find (i) the molecular size of leached amylopectin is 30 times smaller than that of native amylopectin while (ii) that of leached amylose is 5 times smaller than that of native amylose, (iii) the chain-length distribution (CLD: the number of monomer units in a chain on the branched polymer) of leached amylopectin is similar to native amylopectin while (iv) the CLD of leached amylose is much narrower than that of the native amylose, and (v) mainly amylopectin, not amylose, leaches out of the granule and rice kernel during cooking. Stickiness is found to increase with decreasing amylose content in the whole grain, and, in the leachate, with increasing total amount of amylopectin, the proportion of short amylopectin chains, and amylopectin molecular size. Molecular adhesion mechanisms are put forward to explain this result. This molecular structural mechanism provides a new tool for rice breeders to select cultivars with desirable palatability by quantifying the components and molecular structure of leached starch.

  12. Spatial control of translation repression and polarized growth by conserved NDR kinase Orb6 and RNA-binding protein Sts5

    PubMed Central

    Nuñez, Illyce; Rodriguez Pino, Marbelys; Wiley, David J; Das, Maitreyi E; Chen, Chuan; Goshima, Tetsuya; Kume, Kazunori; Hirata, Dai; Toda, Takashi; Verde, Fulvia

    2016-01-01

    RNA-binding proteins contribute to the formation of ribonucleoprotein (RNP) granules by phase transition, but regulatory mechanisms are not fully understood. Conserved fission yeast NDR (Nuclear Dbf2-Related) kinase Orb6 governs cell morphogenesis in part by spatially controlling Cdc42 GTPase. Here we describe a novel, independent function for Orb6 kinase in negatively regulating the recruitment of RNA-binding protein Sts5 into RNPs to promote polarized cell growth. We find that Orb6 kinase inhibits Sts5 recruitment into granules, its association with processing (P) bodies, and degradation of Sts5-bound mRNAs by promoting Sts5 interaction with 14-3-3 protein Rad24. Many Sts5-bound mRNAs encode essential factors for polarized cell growth, and Orb6 kinase spatially and temporally controls the extent of Sts5 granule formation. Disruption of this control system affects cell morphology and alters the pattern of polarized cell growth, revealing a role for Orb6 kinase in the spatial control of translational repression that enables normal cell morphogenesis. DOI: http://dx.doi.org/10.7554/eLife.14216.001 PMID:27474797

  13. Spatial control of translation repression and polarized growth by conserved NDR kinase Orb6 and RNA-binding protein Sts5.

    PubMed

    Nuñez, Illyce; Rodriguez Pino, Marbelys; Wiley, David J; Das, Maitreyi E; Chen, Chuan; Goshima, Tetsuya; Kume, Kazunori; Hirata, Dai; Toda, Takashi; Verde, Fulvia

    2016-07-30

    RNA-binding proteins contribute to the formation of ribonucleoprotein (RNP) granules by phase transition, but regulatory mechanisms are not fully understood. Conserved fission yeast NDR (Nuclear Dbf2-Related) kinase Orb6 governs cell morphogenesis in part by spatially controlling Cdc42 GTPase. Here we describe a novel, independent function for Orb6 kinase in negatively regulating the recruitment of RNA-binding protein Sts5 into RNPs to promote polarized cell growth. We find that Orb6 kinase inhibits Sts5 recruitment into granules, its association with processing (P) bodies, and degradation of Sts5-bound mRNAs by promoting Sts5 interaction with 14-3-3 protein Rad24. Many Sts5-bound mRNAs encode essential factors for polarized cell growth, and Orb6 kinase spatially and temporally controls the extent of Sts5 granule formation. Disruption of this control system affects cell morphology and alters the pattern of polarized cell growth, revealing a role for Orb6 kinase in the spatial control of translational repression that enables normal cell morphogenesis.

  14. Composition and Function of Spider Glues Maintained During the Evolution of Cobwebs.

    PubMed

    Jain, Dharamdeep; Zhang, Ci; Cool, Lydia Rose; Blackledge, Todd A; Wesdemiotis, Chrys; Miyoshi, Toshikazu; Dhinojwala, Ali

    2015-10-12

    Capture silks are an interesting class of biological glues that help spiders subdue their prey. Viscid capture silk produced by the orb web spiders is a combination of hygroscopic salts that aid in water uptake and interact with adhesive glycoproteins to make them soft and sticky. The orb was a stepping stone to the evolution of new web types, but little is known about the adhesives in these webs. For instance, cobweb spiders evolved from orb-weaving ancestors and utilize glue in specialized sticky gumfoot threads rather than an elastic spiral. Early investigation suggests that gumfoot adhesives are quite different viscid glues because they lack a visible glycoprotein core, act as viscoelastic fluids rather than solids, and are largely invariant to humidity. Here, we use spectroscopic and staining methods to show that the gumfoot silk produced by Latrodectus hesperus (western black widow) is composed of hygroscopic organic salts and water insoluble glycoproteins, similar to viscid silk, in addition to a low concentration of spider coating peptides reported before. Our adhesion studies reveal that the organic salts play an important role in adhesion, similar to that seen in orb web spiders, but modulating function at much lower humidity. Our work shows more similarities in the viscid silk produced by orb web and cobweb spiders than previously anticipated and provide guidelines for developing synthetic adhesives that can work in dry to humid environments.

  15. Spider web and silk performance landscapes across nutrient space

    PubMed Central

    Blamires, Sean J.; Tseng, Yi-Hsuan; Wu, Chung-Lin; Toft, Søren; Raubenheimer, David; Tso, I.-Min

    2016-01-01

    Predators have been shown to alter their foraging as a regulatory response to recent feeding history, but it remains unknown whether trap building predators modulate their traps similarly as a regulatory strategy. Here we fed the orb web spider Nephila pilipes either live crickets, dead crickets with webs stimulated by flies, or dead crickets without web stimulation, over 21 days to enforce spiders to differentially extract nutrients from a single prey source. In addition to the nutrients extracted we measured web architectures, silk tensile properties, silk amino acid compositions, and web tension after each feeding round. We then plotted web and silk “performance landscapes” across nutrient space. The landscapes had multiple peaks and troughs for each web and silk performance parameter. The findings suggest that N. pilipes plastically adjusts the chemical and physical properties of their web and silk in accordance with its nutritional history. Our study expands the application of the geometric framework foraging model to include a type of predatory trap. Whether it can be applied to other predatory traps requires further testing. PMID:27216252

  16. Spider web and silk performance landscapes across nutrient space.

    PubMed

    Blamires, Sean J; Tseng, Yi-Hsuan; Wu, Chung-Lin; Toft, Søren; Raubenheimer, David; Tso, I-Min

    2016-05-24

    Predators have been shown to alter their foraging as a regulatory response to recent feeding history, but it remains unknown whether trap building predators modulate their traps similarly as a regulatory strategy. Here we fed the orb web spider Nephila pilipes either live crickets, dead crickets with webs stimulated by flies, or dead crickets without web stimulation, over 21 days to enforce spiders to differentially extract nutrients from a single prey source. In addition to the nutrients extracted we measured web architectures, silk tensile properties, silk amino acid compositions, and web tension after each feeding round. We then plotted web and silk "performance landscapes" across nutrient space. The landscapes had multiple peaks and troughs for each web and silk performance parameter. The findings suggest that N. pilipes plastically adjusts the chemical and physical properties of their web and silk in accordance with its nutritional history. Our study expands the application of the geometric framework foraging model to include a type of predatory trap. Whether it can be applied to other predatory traps requires further testing.

  17. Modular evolution of egg case silk genes across orb-weaving spider superfamilies

    PubMed Central

    Garb, Jessica E.; Hayashi, Cheryl Y.

    2005-01-01

    Spider silk proteins (fibroins) are renowned for their extraordinary mechanical properties and biomimetic potential. Despite extensive evolutionary, ecological, and industrial interest in these fibroins, only a fraction of the known silk types have been characterized at the molecular level. Here we report cDNA and genomic sequences of the fibroin TuSp1, which appears to be the major component of tubuliform gland silk, a fiber exclusively synthesized by female spiders for egg case construction. We obtained TuSp1 sequences from 12 spider species that represent the extremes of phylogenetic diversity within the Orbicularia (orb-weaver superfamilies, Araneoidea and Deinopoidea) and finer scale sampling within genera. TuSp1 encodes tandem arrays of an ≈200-aa-long repeat unit and individual repeats are readily aligned, even among species that diverged >125 million years ago. Analyses of these repeats across species reveal the strong influence of concerted evolution, resulting in intragenic homogenization. However, deinopoid TuSp1 repeats also contain insertions of coding, minisatellite-like sequences, an apparent result of replication slippage and nonreciprocal recombination. Phylogenetic analyses of 37 spider fibroin sequences support the monophyly of TuSp1 within the spider fibroin gene family, consistent with a single origin of this ortholog group. The diversity of taxa and silks examined here confirms that repetitive architecture is a general feature of this gene family. Moreover, we show that TuSp1 provides a clear example of modular evolution across a range of phylogenetic levels. PMID:16061817

  18. Electric nets and sticky materials for analysing oviposition behaviour of gravid malaria vectors

    PubMed Central

    2012-01-01

    Background Little is known about how malaria mosquitoes locate oviposition sites in nature. Such knowledge is important to help devise monitoring and control measures that could be used to target gravid females. This study set out to develop a suite of tools that can be used to study the attraction of gravid Anopheles gambiae s.s. towards visual or olfactory cues associated with aquatic habitats. Methods Firstly, the study developed and assessed methods for using electrocuting nets to analyse the orientation of gravid females towards an aquatic habitat. Electric nets (1m high × 0.5m wide) were powered by a 12V battery via a spark box. High and low energy settings were compared for mosquito electrocution and a collection device developed to retain electrocuted mosquitoes when falling to the ground. Secondly, a range of sticky materials and a detergent were tested to quantify if and where gravid females land to lay their eggs, by treating the edge of the ponds and the water surface. A randomized complete block design was used for all experiments with 200 mosquitoes released each day. Experiments were conducted in screened semi-field systems using insectary-reared An. gambiae s.s. Data were analysed by generalized estimating equations. Results An electric net operated at the highest spark box energy of a 400 volt direct current made the net spark, creating a crackling sound, a burst of light and a burning smell. This setting caught 64% less mosquitoes than a net powered by reduced voltage output that could neither be heard nor seen (odds ratio (OR) 0.46; 95% confidence interval (CI) 0.40-0.53, p < 0.001). Three sticky boards (transparent film, glue coated black fly-screen and yellow film) were evaluated as catching devices under electric nets and the transparent and shiny black surfaces were found highly attractive (OR 41.6, 95% CI 19.8 – 87.3, p < 0.001 and OR 28.8, 95% CI 14.5 – 56.8, p < 0.001, respectively) for gravid mosquitoes to land on compared to a

  19. The male of the orb-weaving spider Plebs mitratus (Simon, 1895) and a redescription of the female (Araneae, Araneidae).

    PubMed

    Paul, Jimmy; Sankaran, Pradeep M; Joseph, Mathew M; Sebastian, Pothalil A

    2016-10-28

    The orb-weaving spider genus Plebs Joseph & Framenau, 2012 currently has only two representatives in India: Plebs himalayaensis (Tikader, 1975) from the Himalayas and Plebs mitratus (Simon, 1895) from the Nilgiris and Anamudi Shola National Park (World Spider Catalog 2016), both are found in high altitude mountainous habitats (Joseph & Framenau 2012). Both species were known only from females (World Spider Catalog 2016), although Sherriffs (1918, 1919) provided a description of an immature male of P. mitratus. In the present paper, we provide the first description of the adult male of P. mitratus, together with the detailed redescription of its female demonstrating considerable intraspecific variation.

  20. Proximate mechanism of behavioral manipulation of an orb-weaver spider host by a parasitoid wasp

    PubMed Central

    Gonzaga, Marcelo Oliveira; de Oliveira, Leandro Licursi; Sperber, Carlos Frankl

    2017-01-01

    Some ichneumonid wasps induce modifications in the web building behavior of their spider hosts to produce resistant “cocoon” webs. These structures hold and protect the wasp’s cocoon during pupa development. The mechanism responsible for host manipulation probably involves the inoculation of psychotropic chemicals by the parasitoid larva during a specific developmental period. Recent studies indicate that some spiders build cocoon webs similar to those normally built immediately before ecdysis, suggesting that this substance might be a molting hormone or a precursor chemical of this hormone. Here, we report that Cyclosa spider species exhibiting modified behavior presented higher 20-OH-ecdysone levels than parasitized spiders acting normally or unparasitized individuals. We suggest that the lack of control that spiders have when constructing modified webs can be triggered by anachronic activation of ecdysis. PMID:28158280

  1. Proximate mechanism of behavioral manipulation of an orb-weaver spider host by a parasitoid wasp.

    PubMed

    Kloss, Thiago Gechel; Gonzaga, Marcelo Oliveira; de Oliveira, Leandro Licursi; Sperber, Carlos Frankl

    2017-01-01

    Some ichneumonid wasps induce modifications in the web building behavior of their spider hosts to produce resistant "cocoon" webs. These structures hold and protect the wasp's cocoon during pupa development. The mechanism responsible for host manipulation probably involves the inoculation of psychotropic chemicals by the parasitoid larva during a specific developmental period. Recent studies indicate that some spiders build cocoon webs similar to those normally built immediately before ecdysis, suggesting that this substance might be a molting hormone or a precursor chemical of this hormone. Here, we report that Cyclosa spider species exhibiting modified behavior presented higher 20-OH-ecdysone levels than parasitized spiders acting normally or unparasitized individuals. We suggest that the lack of control that spiders have when constructing modified webs can be triggered by anachronic activation of ecdysis.

  2. Web Mining

    NASA Astrophysics Data System (ADS)

    Fürnkranz, Johannes

    The World-Wide Web provides every internet citizen with access to an abundance of information, but it becomes increasingly difficult to identify the relevant pieces of information. Research in web mining tries to address this problem by applying techniques from data mining and machine learning to Web data and documents. This chapter provides a brief overview of web mining techniques and research areas, most notably hypertext classification, wrapper induction, recommender systems and web usage mining.

  3. Radar Studies of the Trunk and `Sticky Spot' of Kamb Ice Stream

    NASA Astrophysics Data System (ADS)

    Jacobel, R. W.; Pettersson, R.; Osterhouse, D.; Tulaczyk, S.; Howat, I.

    2005-12-01

    During the 2004-05 Antarctic field season we acquired approximately 275 km of ground-based ice-penetrating radar data on the trunk of Kamb Ice Stream (KIS) as a part of a two-year program of radar and GPS studies examining the possibility of ice stream reactivation. Many of the profiles explore a region of near-stagnant ice, the `sticky spot', in the vicinity of camps occupied by a number of groups from 1986-2000 and which was the focus of extensive borehole studies by Cal Tech in 1996 and 2000. We also investigated an area of the trunk approximately 80 km upstream where repeat laser altimeter profiling revealed an anomalous 4m surface uplift of between 1998-2000 (Spikes, et al., 2003). The radar data image bedrock and internal layer stratigraphy in detail; in many cases the layers are present nearly to the bottom. We have identified a bright layer at about two-thirds to three-fourths of the ice thickness in all profiles. This is likely is the same bright layer that we have detected throughout West Antarctica in ITASE traverses and dated to 17.5 KY (Jacobel and Welch, 2004). We have also produced maps of variations in bed reflectivity that correspond closely (but not identically) with the surface expression of the sticky spot in satellite imagery. Bright areas of the bed are found in the trunk of the ice stream on both sides of the sticky spot and also along the south margin where a layer of liquid water was identified in Cal Tech bore hole 00-01 (Englehart et al., in press). However, the brightest bed reflections are found in the area of anomalous surface uplift. Echoes from near the bed at this location indicate the possible presence of a highly reflective surface off to one side of our profiles. Our bed amplitude studies are augmented by two densely-spaced constant midpoint profiles that enable us to characterize attenuation and e/m wave speed within the ice at locations that are both stagnant and fast-moving. In addition, we have re-imaged fold features in the

  4. Web-building spiders attract prey by storing decaying matter

    NASA Astrophysics Data System (ADS)

    Bjorkman-Chiswell, Bojun T.; Kulinski, Melissa M.; Muscat, Robert L.; Nguyen, Kim A.; Norton, Briony A.; Symonds, Matthew R. E.; Westhorpe, Gina E.; Elgar, Mark A.

    The orb-weaving spider Nephila edulis incorporates into its web a band of decaying animal and plant matter. While earlier studies demonstrate that larger spiders utilise these debris bands as caches of food, the presence of plant matter suggests additional functions. When organic and plastic items were placed in the webs of N. edulis, some of the former but none of the latter were incorporated into the debris band. Using an Y-maze olfactometer, we show that sheep blowflies Lucilia cuprina are attracted to recently collected debris bands, but that this attraction does not persist over time. These data reveal an entirely novel foraging strategy, in which a sit-and-wait predator attracts insect prey by utilising the odours of decaying organic material. The spider's habit of replenishing the debris band may be necessary to maintain its efficacy for attracting prey.

  5. New antiinflammatory sucrose esters in the natural sticky coating of tomatillo (Physalis philadelphica), an important culinary fruit.

    PubMed

    Zhang, Chuan-Rui; Khan, Wajid; Bakht, Jehan; Nair, Muraleedharan G

    2016-04-01

    Tomatillo is a popular culinary fruit. The sticky material on its surface, consumed as part of the fruit, has never been investigated. Chemical characterization of sticky material on tomatillo fruits yielded five new sucrose esters, as confirmed by spectroscopic methods. The solvent extract of the sticky material from the whole fresh fruit and pure isolates showed antiinflammatory activity as confirmed by in vitro cyclooxygenase enzymes inhibitory assays. Five sucrose esters isolated at 100 μg/mL (153.8, 138.8, 136.2, 141.6 and 138.8 μM, respectively) inhibited cyclooxygenase-1 and -2 enzymes by 50%. The cyclooxygenase enzyme inhibitory activity of extract and isolates at 100 μg/mL was similar to non-steroidal antiinflammatory drugs aspirin, ibuprofen and naproxen, used as positive controls in the assay at 108, 12 and 15 μg/mL (600, 60 and 60 μM), respectively.

  6. Evaluating potential sources of variation in Chironomidae catch rates on sticky traps

    USGS Publications Warehouse

    Smith, Joshua T.; Muehlbauer, Jeffrey D.; Kennedy, Theodore

    2016-01-01

    Sticky traps are a convenient tool for assessing adult aquatic insect population dynamics, but there are many practical questions about how trap sampling artefacts may affect observed results. Utilising study sites on the Colorado River and two smaller streams in northern Arizona, USA, we evaluated whether catch rates and sex ratios of Chironomidae, a ubiquitous aquatic insect, were affected by spraying traps with insecticide, placing traps at different heights above ground, and placing traps at different locations within a terrestrial habitat patch. We also evaluated temporal variation in Chironomidae counts monthly over a 9-month growing season. We found no significant variation in catch rates or sex ratios between traps treated versus untreated with insecticide, nor between traps placed at the upstream or downstream end of a terrestrial habitat patch. Traps placed near ground level did have significantly higher catch rates than traps placed at 1.5 m, although sex ratios were similar across heights. Chironomidae abundance and sex ratios also varied from month-to-month and seemed to be related to climatic conditions. Our results inform future sticky trap studies by demonstrating that trap height, but not insecticide treatment or precise trap placement within a habitat patch, is an important source of variation influencing catch rates.

  7. Self-Reported Stickiness of Mind-Wandering Affects Task Performance

    PubMed Central

    van Vugt, Marieke K.; Broers, Nico

    2016-01-01

    When asked to perform a certain task, we typically spend a decent amount of time thinking thoughts unrelated to that task–a phenomenon referred to as “mind-wandering.” It is thought that this mind-wandering is driven at least in part by our unfinished goals and concerns. Previous studies have shown that just after presenting a participant with their own concerns, their reports of task-unrelated thinking increased somewhat. However, effects of these concerns on task performance were somewhat inconsistent. In this study we take the opposite approach, and examine whether task performance depends on the self-reported thought content. Specifically, a particularly intriguing aspect of mind-wandering that has hitherto received little attention is the difficulty of disengaging from it, in other words, the “stickiness” of the thoughts. While presenting participants with their own concerns was not associated with clear effects on task performance, we showed that the reports of off-task thinking and variability of response times increased with the amount of self-reported stickiness of thoughts. This suggests that the stickiness of mind-wandering is a relevant variable, and participants are able to meaningfully report on it. PMID:27242636

  8. High-performance liquid chromatography determination of red wine tannin stickiness.

    PubMed

    Revelette, Matthew R; Barak, Jennifer A; Kennedy, James A

    2014-07-16

    Red wine astringency is generally considered to be the sensory result of salivary protein precipitation following tannin-salivary protein interaction and/or tannin adhering to the oral mucosa. Astringency in red wine is often described using qualitative terms, such as hard and soft. Differences in qualitative description are thought to be due in part to the tannin structure. Tannin chemistry contributions to qualitative description have been shown to correlate with the enthalpy of interaction between tannin and a hydrophobic surface. On the basis of these findings, a method was developed that enabled the routine determination of the thermodynamics of the tannin interaction with a hydrophobic surface (polystyrene divinylbenzene) for tannins in red wine following direct injection. The optimized analytical method monitored elution at four different column temperatures (25-40 °C, in 5 °C increments), had a 20 min run time, and was monitored at 280 nm. The results of this study confirm that the calculated thermodynamics of the interaction are intensive and, therefore, provide specific thermodynamic information. Variation in the enthalpy of interaction between tannin and a hydrophobic surface (tannin stickiness) is a unique, concentration-independent analytical parameter. The method, in addition to providing information on tannin stickiness, provides the tannin concentration.

  9. Accumulation of unstable periodic orbits and the stickiness in the two-dimensional piecewise linear map.

    PubMed

    Akaishi, A; Shudo, A

    2009-12-01

    We investigate the stickiness of the two-dimensional piecewise linear map with a family of marginal unstable periodic orbits (FMUPOs), and show that a series of unstable periodic orbits accumulating to FMUPOs plays a significant role to give rise to the power law correlation of trajectories. We can explicitly specify the sticky zone in which unstable periodic orbits whose stability increases algebraically exist, and find that there exists a hierarchy in accumulating periodic orbits. In particular, the periodic orbits with linearly increasing stability play the role of fundamental cycles as in the hyperbolic systems, which allows us to apply the method of cycle expansion. We also study the recurrence time distribution, especially discussing the position and size of the recurrence region. Following the definition adopted in one-dimensional maps, we show that the recurrence time distribution has an exponential part in the short time regime and an asymptotic power law part. The analysis on the crossover time T(c)(*) between these two regimes implies T(c)(*) approximately -log[micro(R)] where micro(R) denotes the area of the recurrence region.

  10. Trap height and orientation of yellow sticky traps affect capture of Chaetocnema pulicaria (Coleoptera: Chrysomelidae).

    PubMed

    Esker, P D; Obrycki, J; Nutter, F W

    2004-02-01

    Field studies were conducted in Iowa during 2001 and 2002 to determine the optimal sampling height and orientation for using yellow sticky cards to monitor populations of Chaetocnema pulicaria Melsheimer, the vector of the bacterial pathogen Pantoea stewartii subsp, stewartii, the causal organism of Stewart's disease of corn, Zea mays L.. Sticky cards were placed at five different heights (0.15, 0.30, 0.45, 0.60, and 0.90 m) and three orientations (horizontal, vertical, and 30 degree angle) at three locations (Ames, Crawfordsville, and Sutherland) in 2001 and two locations (Crawfordsville and Johnston) in 2002. No statistical differences were observed among the placement combinations for individual sampling periods or for the total number of C. pulicaria captured in 2001. In 2002, the 0.30 m and vertical cards captured significantly (1.1-35 times) more C. pulicaria than any other placement combination during sampling throughout August at both Crawfordsville and Johnston. Also, the cumulative number of C. pulicaria captured by the 0.30 m and vertical cards was significantly higher than all other placement combinations. This information is important in the development of sampling protocols to aid growers in making management decisions. These management decisions include where and when to apply foliar insecticides during the corn growing season to control C. pulicaria populations, thereby reducing the risk for Stewart's disease of corn.

  11. Preparation of Sticky Escherichia coli through Surface Display of an Adhesive Catecholamine Moiety

    PubMed Central

    Park, Joseph P.; Choi, Min-Jung; Kim, Se Hun

    2014-01-01

    Mussels attach to virtually all types of inorganic and organic surfaces in aqueous environments, and catecholamines composed of 3,4-dihydroxy-l-phenylalanine (DOPA), lysine, and histidine in mussel adhesive proteins play a key role in the robust adhesion. DOPA is an unusual catecholic amino acid, and its side chain is called catechol. In this study, we displayed the adhesive moiety of DOPA-histidine on Escherichia coli surfaces using outer membrane protein W as an anchoring motif for the first time. Localization of catecholamines on the cell surface was confirmed by Western blot and immunofluorescence microscopy. Furthermore, cell-to-cell cohesion (i.e., cellular aggregation) induced by the displayed catecholamine and synthesis of gold nanoparticles on the cell surface support functional display of adhesive catecholamines. The engineered E. coli exhibited significant adhesion onto various material surfaces, including silica and glass microparticles, gold, titanium, silicon, poly(ethylene terephthalate), poly(urethane), and poly(dimethylsiloxane). The uniqueness of this approach utilizing the engineered sticky E. coli is that no chemistry for cell attachment are necessary, and the ability of spontaneous E. coli attachment allows one to immobilize the cells on challenging material surfaces such as synthetic polymers. Therefore, we envision that mussel-inspired catecholamine yielded sticky E. coli that can be used as a new type of engineered microbe for various emerging fields, such as whole living cell attachment on versatile material surfaces, cell-to-cell communication systems, and many others. PMID:24123747

  12. Phase behavior of the modified-Yukawa fluid and its sticky limit

    NASA Astrophysics Data System (ADS)

    Schöll-Paschinger, Elisabeth; Valadez-Pérez, Néstor E.; Benavides, Ana L.; Castañeda-Priego, Ramón

    2013-11-01

    Simple model systems with short-range attractive potentials have turned out to play a crucial role in determining theoretically the phase behavior of proteins or colloids. However, as pointed out by D. Gazzillo [J. Chem. Phys. 134, 124504 (2011)], one of these widely used model potentials, namely, the attractive hard-core Yukawa potential, shows an unphysical behavior when one approaches its sticky limit, since the second virial coefficient is diverging. However, it is exactly this second virial coefficient that is typically used to depict the experimental phase diagram for a large variety of complex fluids and that, in addition, plays an important role in the Noro-Frenkel scaling law [J. Chem. Phys. 113, 2941 (2000)], which is thus not applicable to the Yukawa fluid. To overcome this deficiency of the attractive Yukawa potential, D. Gazzillo has proposed the so-called modified hard-core attractive Yukawa fluid, which allows one to correctly obtain the second and third virial coefficients of adhesive hard-spheres starting from a system with an attractive logarithmic Yukawa-like interaction. In this work we present liquid-vapor coexistence curves for this system and investigate its behavior close to the sticky limit. Results have been obtained with the self-consistent Ornstein-Zernike approximation (SCOZA) for values of the reduced inverse screening length parameter up to 18. The accuracy of SCOZA has been assessed by comparison with Monte Carlo simulations.

  13. Sticky platelets syndrome in a young patient with massive pulmonary embolism

    PubMed Central

    Darulová, Stanislava; Samoš, Matej; Sokol, Juraj; Šimonová, Radoslava; Kovář, František; Galajda, Peter; Staško, Ján; Kubisz, Peter; Mokáň, Marián

    2013-01-01

    Patient: Female, 51 Final Diagnosis: Sticky platelets syndrome Symptoms: Pulmonary embolism Medication: — Clinical Procedure: Thrombolysis Specialty: Hematology Objective: Disease of unknown ethiology Background: Sticky platelets syndrome (SPS) is an inherited thrombophilia characterized by platelet hyperaggregability, which can lead to the higher risk of thrombosis. The etiology of SPS remains unclear, but several gene polymorphisms have been recently studied and autosomal dominant heredity is suspected. Although SPS is traditionally connected with arterial thrombosis, several cases of SPS as a cause of venous thromboembolism have been described. Case Report: We report the case of a 51-year-old apparently healthy woman with massive pulmonary embolism, who required thrombolytic therapy. In this patient SPS was identified as the only condition leading to higher risk of developing thromboembolic disease. Conclusions: Although at present few physicians have practical experience with SPS, this syndrome may lead to serious health problems or even death. The presented case points to the benefit of SPS diagnostics in standard screening of inherited thrombophilia for effective prophylaxis and treatment in patients with venous thromboembolism. PMID:23826459

  14. Opposing actions of septins and Sticky on Anillin promote the transition from contractile to midbody ring

    PubMed Central

    El Amine, Nour; Kechad, Amel; Jananji, Silvana

    2013-01-01

    During cytokinesis, closure of the actomyosin contractile ring (CR) is coupled to the formation of a midbody ring (MR), through poorly understood mechanisms. Using time-lapse microscopy of Drosophila melanogaster S2 cells, we show that the transition from the CR to the MR proceeds via a previously uncharacterized maturation process that requires opposing mechanisms of removal and retention of the scaffold protein Anillin. The septin cytoskeleton acts on the C terminus of Anillin to locally trim away excess membrane from the late CR/nascent MR via internalization, extrusion, and shedding, whereas the citron kinase Sticky acts on the N terminus of Anillin to retain it at the mature MR. Simultaneous depletion of septins and Sticky not only disrupted MR formation but also caused earlier CR oscillations, uncovering redundant mechanisms of CR stability that can partly explain the essential role of Anillin in this process. Our findings highlight the relatedness of the CR and MR and suggest that membrane removal is coordinated with CR disassembly. PMID:24217622

  15. Sticky shocker

    NASA Astrophysics Data System (ADS)

    Vasel, Edward; Bryars, John; Coakley, Peter G.; Mallon, Charles E.; Millard, Jeffrey R.; Niederhaus, Gregory A.; Nunan, Scott C.

    1997-01-01

    A nonlethal method is being developed to extend the range for effectively electrically stunning a person. Present technology, consisting of stun guns and tasers, is limited to distances of < 2 or 3 m. This new concept involves firing a blunt projectile at an individual, which will stick to his clothing with a glue-like substance or with short clothing attachment barbs. The projectile contains a battery pack and associated electronics that will impart a short burst of high-voltage pulses. Pulse amplitudes are near 50 kV with pulse widths of a few micro-seconds and a repetition rate between 10 and 15 pulses per second. The pulse characteristics are similar to well-established electrical shock devices. The pulses will not be lethal, but will disable or cause enough discomfort to the individual to distract him. A compressed gas-charged launch system has been fabricated and tested, and projectile designs compatible with conventional nonlethal weapon launchers are being developed. The projectile is accurate at 10 m and limited tests indicate that it is accurate out to 30 m as well. The presentation will discuss electric shock voltage characterization, projectile configuration, and limited prototype field demonstration test data recorded on instrumented targets.

  16. Improved removal of sticky and light contaminants from wastepaper. Final report, April 1, 1995--December 31, 1997

    SciTech Connect

    Seifert, P.; Kelly, A.

    1998-03-01

    Work under this two-year cooperative agreement addresses improved removal of light and sticky contaminants from waste paper. Such contaminants occur in ever-increasing amounts, resulting from glues, labels, book bindings, packaging tapes, etc., all associated with the waste paper stream. Despite various cleaning steps in the paper mill recycling systems, residual contamination remains, causing big problems with the product quality and with paper machine and converting operations. Some grades cannot be recycled at all. Stickies are truly a barrier against increased paper recycling. The stickies problem was attacked in four project segments--three of those have yielded tangible results. One segment has been outstanding in its success; namely, the development of a centrifugal reverse cleaning system consisting of primary and secondary stages, which have unparalleled high efficiency in the removal of light and sticky contaminants. This cleaning system, consists of primary XTREME and secondary XX-Clone units. Another segment of this work, washing wax contaminated old corrugated wastepaper (OCC), also has resulted in the new Xtrax process which was released for sale.

  17. A wind-oriented sticky trap for evaluating the behavioural response of diabrotica speciosa (germar) to bitter cucurbit extracts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cucurbitacins attract many species of Luperini leaf beetles, for which they have been studied and applied in traps and toxic baits. Males and females feed avidly on these compounds, but field trials reveal that males are far more attracted to them than females. A wind oriented baited sticky trap was...

  18. Monitoring insects in sweetpotatoes with sweep net and sticky traps across the Mississippi Delta: a omparative study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect populations in sweetpotato fields in the Mississippi Delta were monitored in 2007 by comparing traditional sweep net sampling with purple and yellow sticky traps. Four sweep net samples each consisting of 25 sweeps were taken weekly from each of four different locations from 2 July to 3 Sept...

  19. Populations of sharpshooters in two citrus groves in east-central Florida as indicated by yellow sticky card traps

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three sharpshooter species were captured on yellow sticky card traps in two citrus groves in east-central Florida: Homalodisca insolita, H. vitripennis and Oncometopia nigricans. H. vitripennis and O. nigricans were relatively common and H. vitripennis relatively abundant over a three year period ...

  20. Structural and optical studies on selected web spinning spider silks

    NASA Astrophysics Data System (ADS)

    Karthikeyani, R.; Divya, A.; Mathavan, T.; Asath, R. Mohamed; Benial, A. Milton Franklin; Muthuchelian, K.

    2017-01-01

    This study investigates the structural and optical properties in the cribellate silk of the sheet web spider Stegodyphus sarasinorum Karsch (Eresidae) and the combined dragline, viscid silk of the orb-web spiders Argiope pulchella Thorell (Araneidae) and Nephila pilipes Fabricius (Nephilidae). X-ray diffraction (XRD), Fourier transform infra-red (FTIR), Ultraviolet-visible (UV-Vis) and fluorescence spectroscopic techniques were used to study these three spider silk species. X-ray diffraction data are consistent with the amorphous polymer network which is arising from the interaction of larger side chain amino acid contributions due to the poly-glycine rich sequences known to be present in the proteins of cribellate silk. The same amorphous polymer networks have been determined from the combined dragline and viscid silk of orb-web spiders. From FTIR spectra the results demonstrate that, cribellate silk of Stegodyphus sarasinorum, combined dragline viscid silk of Argiope pulchella and Nephila pilipes spider silks are showing protein peaks in the amide I, II and III regions. Further they proved that the functional groups present in the protein moieties are attributed to α-helical and side chain amino acid contributions. The optical properties of the obtained spider silks such as extinction coefficients, refractive index, real and imaginary dielectric constants and optical conductance were studied extensively from UV-Vis analysis. The important fluorescent amino acid tyrosine is present in the protein folding was investigated by using fluorescence spectroscopy. This research would explore the protein moieties present in the spider silks which were found to be associated with α-helix and side chain amino acid contributions than with β-sheet secondary structure and also the optical relationship between the three different spider silks are investigated. Successful spectroscopic knowledge of the internal protein structure and optical properties of the spider silks could

  1. Structural and optical studies on selected web spinning spider silks.

    PubMed

    Karthikeyani, R; Divya, A; Mathavan, T; Asath, R Mohamed; Benial, A Milton Franklin; Muthuchelian, K

    2017-01-05

    This study investigates the structural and optical properties in the cribellate silk of the sheet web spider Stegodyphus sarasinorum Karsch (Eresidae) and the combined dragline, viscid silk of the orb-web spiders Argiope pulchella Thorell (Araneidae) and Nephila pilipes Fabricius (Nephilidae). X-ray diffraction (XRD), Fourier transform infra-red (FTIR), Ultraviolet-visible (UV-Vis) and fluorescence spectroscopic techniques were used to study these three spider silk species. X-ray diffraction data are consistent with the amorphous polymer network which is arising from the interaction of larger side chain amino acid contributions due to the poly-glycine rich sequences known to be present in the proteins of cribellate silk. The same amorphous polymer networks have been determined from the combined dragline and viscid silk of orb-web spiders. From FTIR spectra the results demonstrate that, cribellate silk of Stegodyphus sarasinorum, combined dragline viscid silk of Argiope pulchella and Nephila pilipes spider silks are showing protein peaks in the amide I, II and III regions. Further they proved that the functional groups present in the protein moieties are attributed to α-helical and side chain amino acid contributions. The optical properties of the obtained spider silks such as extinction coefficients, refractive index, real and imaginary dielectric constants and optical conductance were studied extensively from UV-Vis analysis. The important fluorescent amino acid tyrosine is present in the protein folding was investigated by using fluorescence spectroscopy. This research would explore the protein moieties present in the spider silks which were found to be associated with α-helix and side chain amino acid contributions than with β-sheet secondary structure and also the optical relationship between the three different spider silks are investigated. Successful spectroscopic knowledge of the internal protein structure and optical properties of the spider silks could

  2. Web orientation and prey resources for web-building spiders in eastern hemlock.

    PubMed

    Mallis, Rachael E; Rieske, Lynne K

    2010-10-01

    We examined the arthropod community on eastern hemlock, Tsuga canadensis (L.) Carr, in the context of its role in providing potential prey items for hemlock-associated web-weaving spiders. Using sticky traps simulating spider webs, we evaluated what prey items are available to web-weaving spiders in eastern hemlock based on web orientation (horizontal versus vertical) and cardinal direction. We found that the overwhelming majority (>70%) of prey items available to spiders in hemlock canopies were Diptera. Psocoptera, Hymenoptera, and Hemiptera comprised most of the remaining potential prey. A significant direction × orientation interaction, and greater trap capture in some direction-orientation combinations, suggests that spiders might locate their webs in eastern hemlock canopies for thermoregulatory purposes, ultimately optimizing prey capture. We also evaluated these findings in the context of hemlock infestation by the invasive hemlock woolly adelgid, Adelges tsugae Annand. The adelgid is a sedentary insect with a mobile crawler stage that provides a readily available, easily obtained food source for predators in hemlock canopies. However, an abundance of alternative prey will affect within canopy spider distribution and the potential intensity with which spiders consume these prey. Understanding the response of spiders to potential prey availability is essential to understanding the trophic interactions involving these predators and their potential for influencing herbivore populations.

  3. High-performance spider webs: integrating biomechanics, ecology and behaviour.

    PubMed

    Harmer, Aaron M T; Blackledge, Todd A; Madin, Joshua S; Herberstein, Marie E

    2011-04-06

    Spider silks exhibit remarkable properties, surpassing most natural and synthetic materials in both strength and toughness. Orb-web spider dragline silk is the focus of intense research by material scientists attempting to mimic these naturally produced fibres. However, biomechanical research on spider silks is often removed from the context of web ecology and spider foraging behaviour. Similarly, evolutionary and ecological research on spiders rarely considers the significance of silk properties. Here, we highlight the critical need to integrate biomechanical and ecological perspectives on spider silks to generate a better understanding of (i) how silk biomechanics and web architectures interacted to influence spider web evolution along different structural pathways, and (ii) how silks function in an ecological context, which may identify novel silk applications. An integrative, mechanistic approach to understanding silk and web function, as well as the selective pressures driving their evolution, will help uncover the potential impacts of environmental change and species invasions (of both spiders and prey) on spider success. Integrating these fields will also allow us to take advantage of the remarkable properties of spider silks, expanding the range of possible silk applications from single threads to two- and three-dimensional thread networks.

  4. High-performance spider webs: integrating biomechanics, ecology and behaviour

    PubMed Central

    Harmer, Aaron M. T.; Blackledge, Todd A.; Madin, Joshua S.; Herberstein, Marie E.

    2011-01-01

    Spider silks exhibit remarkable properties, surpassing most natural and synthetic materials in both strength and toughness. Orb-web spider dragline silk is the focus of intense research by material scientists attempting to mimic these naturally produced fibres. However, biomechanical research on spider silks is often removed from the context of web ecology and spider foraging behaviour. Similarly, evolutionary and ecological research on spiders rarely considers the significance of silk properties. Here, we highlight the critical need to integrate biomechanical and ecological perspectives on spider silks to generate a better understanding of (i) how silk biomechanics and web architectures interacted to influence spider web evolution along different structural pathways, and (ii) how silks function in an ecological context, which may identify novel silk applications. An integrative, mechanistic approach to understanding silk and web function, as well as the selective pressures driving their evolution, will help uncover the potential impacts of environmental change and species invasions (of both spiders and prey) on spider success. Integrating these fields will also allow us to take advantage of the remarkable properties of spider silks, expanding the range of possible silk applications from single threads to two- and three-dimensional thread networks. PMID:21036911

  5. Spider webs designed for rare but life-saving catches.

    PubMed

    Venner, Samuel; Casas, Jérôme

    2005-08-07

    The impact of rare but positive events on the design of organisms has been largely ignored, probably due to the paucity of recordings of such events and to the difficulty of estimating their impact on lifetime reproductive success. In this respect, we investigated the size of spider webs in relation to rare but large prey catches. First, we collected field data on a short time-scale using the common orb-weaving spider Zygiella x-notata to determine the distribution of the size of prey caught and to quantify the relationship between web size and daily capture success. Second, we explored, with an energetic model, the consequences of an increase in web size on spider fitness. Our results showed that (i) the great majority of prey caught are quite small (body length less than 2mm) while large prey (length greater than 10mm) are rare, (ii) spiders cannot survive or produce eggs without catching these large but rare prey and (iii) increasing web size increases the daily number of prey caught and thus long-term survival and fecundity. Spider webs seem, therefore, designed for making the best of the rare but crucial event of catching large prey.

  6. The dsRNA Virus Papaya Meleira Virus and an ssRNA Virus Are Associated with Papaya Sticky Disease

    PubMed Central

    Sá Antunes, Tathiana Ferreira; Amaral, Raquel J. Vionette; Ventura, José Aires; Godinho, Marcio Tadeu; Amaral, Josiane G.; Souza, Flávia O.; Zerbini, Poliane Alfenas; Zerbini, Francisco Murilo

    2016-01-01

    Papaya sticky disease, or “meleira”, is one of the major diseases of papaya in Brazil and Mexico, capable of causing complete crop loss. The causal agent of sticky disease was identified as an isometric virus with a double stranded RNA (dsRNA) genome, named papaya meleira virus (PMeV). In the present study, PMeV dsRNA and a second RNA band of approximately 4.5 kb, both isolated from latex of papaya plants with severe symptoms of sticky disease, were deep-sequenced. The nearly complete sequence obtained for PMeV dsRNA is 8,814 nucleotides long and contains two putative ORFs; the predicted ORF1 and ORF2 display similarity to capsid proteins and RdRp's, respectively, from mycoviruses tentatively classified in the family Totiviridae. The sequence obtained for the second RNA is 4,515 nucleotides long and contains two putative ORFs. The predicted ORFs 1 and 2 display 48% and 73% sequence identity, respectively, with the corresponding proteins of papaya virus Q, an umbravirus recently described infecting papaya in Ecuador. Viral purification in a sucrose gradient allowed separation of particles containing each RNA. Mass spectrometry analysis indicated that both PMeV and the second RNA virus (named papaya meleira virus 2, PMeV2) were encapsidated in particles formed by the protein encoded by PMeV ORF1. The presence of both PMeV and PMeV2 was confirmed in field plants showing typical symptoms of sticky disease. Interestingly, PMeV was detected alone in asymptomatic plants. Together, our results indicate that sticky disease is associated with double infection by PMeV and PMeV2. PMID:27166626

  7. The dsRNA Virus Papaya Meleira Virus and an ssRNA Virus Are Associated with Papaya Sticky Disease.

    PubMed

    Sá Antunes, Tathiana Ferreira; Amaral, Raquel J Vionette; Ventura, José Aires; Godinho, Marcio Tadeu; Amaral, Josiane G; Souza, Flávia O; Zerbini, Poliane Alfenas; Zerbini, Francisco Murilo; Fernandes, Patricia Machado Bueno

    2016-01-01

    Papaya sticky disease, or "meleira", is one of the major diseases of papaya in Brazil and Mexico, capable of causing complete crop loss. The causal agent of sticky disease was identified as an isometric virus with a double stranded RNA (dsRNA) genome, named papaya meleira virus (PMeV). In the present study, PMeV dsRNA and a second RNA band of approximately 4.5 kb, both isolated from latex of papaya plants with severe symptoms of sticky disease, were deep-sequenced. The nearly complete sequence obtained for PMeV dsRNA is 8,814 nucleotides long and contains two putative ORFs; the predicted ORF1 and ORF2 display similarity to capsid proteins and RdRp's, respectively, from mycoviruses tentatively classified in the family Totiviridae. The sequence obtained for the second RNA is 4,515 nucleotides long and contains two putative ORFs. The predicted ORFs 1 and 2 display 48% and 73% sequence identity, respectively, with the corresponding proteins of papaya virus Q, an umbravirus recently described infecting papaya in Ecuador. Viral purification in a sucrose gradient allowed separation of particles containing each RNA. Mass spectrometry analysis indicated that both PMeV and the second RNA virus (named papaya meleira virus 2, PMeV2) were encapsidated in particles formed by the protein encoded by PMeV ORF1. The presence of both PMeV and PMeV2 was confirmed in field plants showing typical symptoms of sticky disease. Interestingly, PMeV was detected alone in asymptomatic plants. Together, our results indicate that sticky disease is associated with double infection by PMeV and PMeV2.

  8. Gravitational waves, energy and Feynman’s “sticky bead”

    NASA Astrophysics Data System (ADS)

    Cooperstock, F. I.

    2015-07-01

    It is noted that in the broader sense, gravitational waves viewed as spacetime curvature which necessarily accompanies electromagnetic waves at the speed of light, are the routine perception of our everyday experience. We focus on the energy issue and Feynman’s “sticky bead” argument which has been regarded as central in supporting the conclusion that gravitational waves carry energy through the vacuum in general relativity. We discuss the essential neglected aspects of his approach which leads to the conclusion that gravitational waves would not cause Feynman’s bead to heat the stick on which it would supposedly rub. This opens the way to an examination of the entire issue of energy in general relativity. We briefly discuss our naturally-defined totally invariant spacetime energy expression for general relativity incorporating the contribution from gravity. When the cosmological term is included in the field equations, our energy expression includes the vacuum energy as required.

  9. The mean spherical model for a Lorentz-Berthelot mixture of sticky hard spheres

    NASA Astrophysics Data System (ADS)

    Tutschka, Christian; Kahl, Gerhard

    1998-06-01

    We have analyzed the Percus-Yevick (PY) and the mean spherical model (MSM) equation for an N-component system of sticky hard spheres. The PY approximation leads to a set of N(N+1)/2 coupled quadratic equations for the unknown coefficients. While for this closure, the pair distribution functions have to be calculated numerically, we can proceed in the MSM one step further if we assume a Lorentz-Berthelot-type rule for the interactions: then the structure functions can be calculated analytically. We show that under these conditions in the limit N→∞ (stochastic limit) the analyticity of the solution is preserved. General expressions both for the discrete and continuous (polydisperse) case are presented.

  10. 'Sticky' neutrophils, pathergic arthritis, and response to heparin in pyoderma gangrenosum complicating ulcerative colitis.

    PubMed Central

    Dwarakanath, A D; Yu, L G; Brookes, C; Pryce, D; Rhodes, J M

    1995-01-01

    Pyoderma gangrenosum is strongly associated with inflammatory bowel disease and exhibits pathergy, occurring at sites of previous minor trauma. A patient is presented with a 21 year history of extensive ulcerative colitis, who developed pyoderma gangrenosum and arthralgia while receiving high dose corticosteroids for active ulcerative colitis. The arthralgia exhibited pathergy affecting particularly the left temporomandibular joint, which was stressed by an asymmetric bite, and the left elbow, which had been fractured many years previously. This prompted the hypothesis that neutrophils in this condition may be marginated, as a result of increased stickiness of either the neutrophil or the vascular endothelium. The introduction of heparin therapy was associated with rapid resolution of the arthralgia, pyoderma gangrenosum, and ulcerative colitis. Images Figure 1 Figure 3 PMID:7489951

  11. Web Engineering

    SciTech Connect

    White, Bebo

    2003-06-23

    Web Engineering is the application of systematic, disciplined and quantifiable approaches to development, operation, and maintenance of Web-based applications. It is both a pro-active approach and a growing collection of theoretical and empirical research in Web application development. This paper gives an overview of Web Engineering by addressing the questions: (a) why is it needed? (b) what is its domain of operation? (c) how does it help and what should it do to improve Web application development? and (d) how should it be incorporated in education and training? The paper discusses the significant differences that exist between Web applications and conventional software, the taxonomy of Web applications, the progress made so far and the research issues and experience of creating a specialization at the master's level. The paper reaches a conclusion that Web Engineering at this stage is a moving target since Web technologies are constantly evolving, making new types of applications possible, which in turn may require innovations in how they are built, deployed and maintained.

  12. Padé approximation of the adiabatic electron contribution to the gyrokinetic quasi-neutrality equation in the ORB5 code

    NASA Astrophysics Data System (ADS)

    Lanti, E.; Dominski, J.; Brunner, S.; McMillan, B. F.; Villard, L.

    2016-11-01

    This work aims at completing the implementation of a solver for the quasineutrality equation using a Padé approximation in the global gyrokinetic code ORB5. Initially [Dominski, Ph.D. thesis, 2016], the Pade approximation was only implemented for the kinetic electron model. To enable runs with adiabatic or hybrid electron models while using a Pade approximation to the polarization response, the adiabatic response term of the quasi-neutrality equation must be consistently modified. It is shown that the Pade solver is in good agreement with the arbitrary wavelength solver of ORB5 [Dominski, Ph.D. thesis, 2016]. To perform this verification, the linear dispersion relation of an ITG-TEM transition is computed for both solvers and the linear growth rates and frequencies are compared.

  13. Visualization of the spatial and spectral signals of orb-weaving spiders, Nephila pilipes, through the eyes of a honeybee.

    PubMed

    Chiao, Chuan-Chin; Wu, Wen-Yen; Chen, Sheng-Hui; Yang, En-Cheng

    2009-07-01

    It is well known that the honeybee has good color vision. However, the spectral range in which the bee can see is different from that of the human eye. To study how bees view their world of colors, one has to see through the eyes of the bee, not the eyes of a human. A conventional way to examine the color signals that animals can detect is to measure the surface reflectance spectra and compute the quantum catches of each photoreceptor type based on its known spectral sensitivity. Color signal and color contrast are then determined from the loci of these quantum catches in the color space. While the point-by-point measurements of the reflectance spectra using a standard spectrometer have yielded a significant amount of data for analyzing color signals, the lack of spatial information and low sampling efficiency constrain their applications. Using a special filter coating technique, a set of filters with transmission spectra that were closely matched to the bee's sensitivity spectra of three photoreceptor types (UV, blue, and green) was custom made. By placing these filters in front of a UV/VIS-sensitive CCD camera and acquiring images sequentially, we could collect images of a bee's receptor with only three shots. This allowed a direct visualization of how bees view their world in a pseudo-color RGB display. With this imaging system, spatial and spectral signals of the orb-weaving spider, Nephila pilipes, were recorded, and color contrast images corresponding to the bee's spatial resolution were constructed and analyzed. The result not only confirmed that the color markings of N. pilipes are of high chromatic contrast to the eyes of a bee, but it also indicated that the spatial arrangement of these markings resemble flower patterns which may attract bees to visit them. Thus, it is likely that the orb-weaving spider (N. pilipes) deploys a similar strategy to that of the Australian crab spider (Thomisus spectabilis) to exploit the bee's pre-existing preference for

  14. Discrepancies between Aedes aegypti identification in the field and in the laboratory after collection with a sticky trap

    PubMed Central

    Maciel-de-Freitas, Rafael; Lima, Arthur Weiss da Silva; Araújo, Simone Costa; Lima, José Bento Pereira; Galardo, Allan Kardec Ribeiro; Honório, Nildimar Alves; Braga, Ima Aparecida; Coelho, Giovanini Evelim; Codeço, Claudia Torres; Valle, Denise

    2014-01-01

    Currently, sticky traps are regularly employed to assist in the surveillance of Aedes aegypti infestation. We tested two alternative procedures for specimen identification performed by local health agents: directly in the field, as recommended by certain manufacturers, or after transportation to the laboratory. A total of 384 sticky traps (MosquiTRAP) were monitored monthly during one year in four geographically representative Brazilian municipalities. When the same samples were inspected in the field and in the laboratory, large differences were noted in the total number of mosquitoes recorded and in the number of specimens identified as Ae. aegypti by both procedures. Although field identification has the potential to speed vector surveillance, these results point to uncertainties in the evaluated protocol. PMID:25317711

  15. The influence of varied gravito-inertial fields on the cardiac response of orb-weaving spiders

    NASA Technical Reports Server (NTRS)

    Finck, A.

    1982-01-01

    The Gz transfer function was described for the orb weaving spider A. sericatus. The functional relationship between the heartrate and the intensity of G is linear in the form of: Y = a Log Gz-1 +k. The heartrate in unrestrained animals was recorded by a laser plethysmograph developed specifically for this purpose. Following a control, sample heartrate were taken postrotation between 1.001 and 1.5 Gz in 6 steps. The underlying distribution of heartrates does not appear significantly different from a Gaussian distribution. A method of varnishing the legs of the spider was developed. This was done in order to compromise the lyriform organs, especially those located on the patellae. The lyriform organ is hypothesized to serve the receptor role in the transduction of gravity related stimuli. In preliminary animals the Gz function, post varnishing of the patellae, appears to be changed in the direction of poorer discrimination. We also observed that the resting heartrate following the varnish procedure is substantially increased.

  16. Signal polymorphism under a constant environment: the odd cross in a web decorating spider.

    PubMed

    Walter, André; Elgar, Mark A

    2016-12-01

    The quality of many animal signals varies, perhaps through their use in different contexts or by representing an adaptive response to reduce the risk of exploitation. Spiders of the orb weaver genus Argiope add linear, cruciate or circular silk structures to their orb webs, creating inter- and intra-specific polymorphic visual signals. Different decoration patterns are frequently attributed to different signal effects, but this view is contradicted by commonly observed intraspecific variation in decorating behaviour. Adults of Argiope mascordi are bimodal web decorators, building two distinct patterns, circular and cruciate silk structures. We investigated the variation of patterns under controlled, invariant laboratory conditions. Circular decorations were most frequent, but individuals often switch to the other pattern. This variation neither increased nor decreased over time, suggesting that pattern variability is primarily intrinsic rather than an exclusive response to environmental changes. Accordingly, we discuss the evolutionary implications in the light of the conservation of a single signal function through maintaining the variation of its quality and the alternative view that silk decorations may not represent adaptive signals at all.

  17. Signal polymorphism under a constant environment: the odd cross in a web decorating spider

    NASA Astrophysics Data System (ADS)

    Walter, André; Elgar, Mark A.

    2016-12-01

    The quality of many animal signals varies, perhaps through their use in different contexts or by representing an adaptive response to reduce the risk of exploitation. Spiders of the orb weaver genus Argiope add linear, cruciate or circular silk structures to their orb webs, creating inter- and intra-specific polymorphic visual signals. Different decoration patterns are frequently attributed to different signal effects, but this view is contradicted by commonly observed intraspecific variation in decorating behaviour. Adults of Argiope mascordi are bimodal web decorators, building two distinct patterns, circular and cruciate silk structures. We investigated the variation of patterns under controlled, invariant laboratory conditions. Circular decorations were most frequent, but individuals often switch to the other pattern. This variation neither increased nor decreased over time, suggesting that pattern variability is primarily intrinsic rather than an exclusive response to environmental changes. Accordingly, we discuss the evolutionary implications in the light of the conservation of a single signal function through maintaining the variation of its quality and the alternative view that silk decorations may not represent adaptive signals at all.

  18. Comparing rates of springtail predation by web-building spiders using Bayesian inference.

    PubMed

    Welch, Kelton D; Schofield, Matthew R; Chapman, Eric G; Harwood, James D

    2014-08-01

    A major goal of gut-content analysis is to quantify predation rates by predators in the field, which could provide insights into the mechanisms behind ecosystem structure and function, as well as quantification of ecosystem services provided. However, percentage-positive results from molecular assays are strongly influenced by factors other than predation rate, and thus can only be reliably used to quantify predation rates under very restrictive conditions. Here, we develop two statistical approaches, one using a parametric bootstrap and the other in terms of Bayesian inference, to build upon previous techniques that use DNA decay rates to rank predators by their rate of prey consumption, by allowing a statistical assessment of confidence in the inferred ranking. To demonstrate the utility of this technique in evaluating ecological data, we test web-building spiders for predation on a primary prey item, springtails. Using these approaches we found that an orb-weaving spider consumes springtail prey at a higher rate than a syntopic sheet-weaving spider, despite occupying microhabitats where springtails are less frequently encountered. We suggest that spider-web architecture (orb web vs. sheet web) is a primary determinant of prey-consumption rates within this assemblage of predators, which demonstrates the potential influence of predator foraging behaviour on trophic web structure. We also discuss how additional assumptions can be incorporated into the same analysis to allow broader application of the technique beyond the specific example presented. We believe that such modelling techniques can greatly advance the field of molecular gut-content analysis.

  19. Sensor web

    NASA Technical Reports Server (NTRS)

    Delin, Kevin A. (Inventor); Jackson, Shannon P. (Inventor)

    2011-01-01

    A Sensor Web formed of a number of different sensor pods. Each of the sensor pods include a clock which is synchronized with a master clock so that all of the sensor pods in the Web have a synchronized clock. The synchronization is carried out by first using a coarse synchronization which takes less power, and subsequently carrying out a fine synchronization to make a fine sync of all the pods on the Web. After the synchronization, the pods ping their neighbors to determine which pods are listening and responded, and then only listen during time slots corresponding to those pods which respond.

  20. Diurnal variation in invertebrate catch rates by sticky traps: Potential for biased indices of piping plover forage

    USGS Publications Warehouse

    Anteau, M.J.; Sherfy, M.H.

    2010-01-01

    Measuring abundance of invertebrate forage for piping plovers (Charadrius melodus; hereafter plovers), a federally listed species in the USA, is an important component of research and monitoring targeted toward species recovery. Sticky traps are commonly used to passively sample invertebrates, but catch rates may vary diurnally or in response to weather. We examined diurnal variation in catch rates of invertebrates using an experiment on reservoir shoreline and riverine sandbar habitats of the Upper Missouri River in 2006 and 2008. Highest catch rates of large invertebrates (>3 mm) on dry sand habitats occurred during 08:00-11:00 Central Daylight Time (CDT) on the reservoir and 08:00-14:00 CDT on the river. On wet sand habitats, catch rates were lowest during 17:00-20:00 on both the reservoir and the river. Catch rates decreased 24% for every 10 kph increase in wind. Sticky traps deployed continuously for 12 h or more had lower catch rates than four consecutive-composited 3-hour deployments, suggesting that trap effectiveness declined for >3-hour deployments. Thus, if sticky traps are used to index plover forage abundance without controlling for time of day and wind speed, data may be highly variable or estimates could be biased. ?? 2010 Society of Wetland Scientists.

  1. Reducing the porosity and reflection loss of silicon nanowires by a sticky tape

    NASA Astrophysics Data System (ADS)

    Liu, Junjun; Huang, Zhifeng

    2015-05-01

    Engineering the porosity of silicon nanowires (SiNWs) is of fundamental importance, and this work introduces a new method for doing so. Metal-assisted chemical etching (MACE) of heavily doped Si(100) creates mesoporous silicon nanowires (mp-SiNWs). mp-SiNWs are transferred from the MACE-treated wafer to a sticky tape, leaving residues composed of broken mp-SiNWs and a mesoporous Si layer on the wafer. Then the taped wafer is re-treated by MACE, without changing the etching conditions. The second MACE treatment generates mp-SiNWs that are less porous and longer than those generated by the first MACE treatment, which can be attributed to the difference in the surface topography at the beginning of the etching process. Less porous mp-SiNWs reduce optical scattering from the porous Si skeletons, and vertically protrude on the wafer without aggregation to facilitate optical trapping. Consequently, less porous mp-SiNWs effectively reduce ultraviolet-visible reflection loss.

  2. Reducing the porosity and reflection loss of silicon nanowires by a sticky tape.

    PubMed

    Liu, Junjun; Huang, Zhifeng

    2015-05-08

    Engineering the porosity of silicon nanowires (SiNWs) is of fundamental importance, and this work introduces a new method for doing so. Metal-assisted chemical etching (MACE) of heavily doped Si(100) creates mesoporous silicon nanowires (mp-SiNWs). mp-SiNWs are transferred from the MACE-treated wafer to a sticky tape, leaving residues composed of broken mp-SiNWs and a mesoporous Si layer on the wafer. Then the taped wafer is re-treated by MACE, without changing the etching conditions. The second MACE treatment generates mp-SiNWs that are less porous and longer than those generated by the first MACE treatment, which can be attributed to the difference in the surface topography at the beginning of the etching process. Less porous mp-SiNWs reduce optical scattering from the porous Si skeletons, and vertically protrude on the wafer without aggregation to facilitate optical trapping. Consequently, less porous mp-SiNWs effectively reduce ultraviolet-visible reflection loss.

  3. Sticky superhydrophobic filter paper developed by dip-coating of fluorinated waterborne epoxy emulsion

    NASA Astrophysics Data System (ADS)

    Huang, Xiangxuan; Wen, Xiufang; Cheng, Jiang; Yang, Zhuoru

    2012-09-01

    A superhydrophobic and superoleophilic coating for oil filter paper was synthesized based on waterborne bisphenol-A novolac epoxy emulsion. The benzoic acid (BA) and maleic anhydride (MA) were used as modification agents to give the epoxy resin hydrophilic groups (carboxyl) and Cdbnd C double bonds. And the fluorinated waterborne epoxy emulsion was prepared by free radical solution polymerization of dodecafluoroheptyl methacrylate (DFMA) monomer. The covalent bound low free energy fluorinated chains in the monomer reduce the surface energy of solidification polymers sufficiently to give rise to superhydrophobic behavior while conserving superoleophilicity. Surfaces prepared show a sticky property, which exhibits a static water contact angle of 152° for a 5 μL droplet that does not slid off even when the sample is held upside down. This synthetic emulsion is simple and convenient as impregnating agent for filter paper, which can be considered as a suitable candidate for various substrates such as cotton textiles, E-glass and artificial fiber, and so on.

  4. Rational design of a non-canonical "sticky-ended" collagen triple helix.

    PubMed

    Jalan, Abhishek A; Jochim, Katherine A; Hartgerink, Jeffrey D

    2014-05-28

    In a canonical collagen triple helix, three peptides self-assemble into a supercoiled motif with a one-amino-acid offset between the peptide chains. Design of triple helices that contain more than one residue offset is lucrative, as it leaves the non-covalent interactions unsatisfied at the termini and renders the termini "sticky" to further self-assemble into collagen-like nanofibers. Here we use lysine-glutamate axial salt-bridges to design a heterotrimeric collagen triple helix, ABC-1, containing a non-canonical offset of four residues between the peptide chains. The four-residue offset is necessary to prevent aggregation, which would prevent characterization of the non-canonical chain arrangement at the molecular level by NMR spectroscopy. A second heterotrimer, ABC-2, also stabilized by axial salt-bridges, is designed containing a canonical one-amino-acid offset to facilitate comparison of structure and stability by CD and NMR. ABC-1 and ABC-2 demonstrate our ability to modulate chain offset in a collagen triple helix. This lays the groundwork to design longer, and therefore stickier, offsets allowing access to a new class of collagen-related nanostructures.

  5. Designing robust alumina nanowires-on-nanopores structures: superhydrophobic surfaces with slippery or sticky water adhesion.

    PubMed

    Peng, Shan; Tian, Dong; Miao, Xinrui; Yang, Xiaojun; Deng, Wenli

    2013-11-01

    Hierarchical alumina surfaces with different morphologies were fabricated by a simple one-step anodization method. These alumina films were fabricated by a new raw material: silica gel plate (aluminum foil with a low purity of 97.17%). The modulation of anodizing time enabled the formation of nanowires-on-nanopores hybrid nanostructures having controllable nanowires topographies through a self-assembly process. The resultant structures were demonstrated to be able to achieve superhydrophobicity without any hydrophobic coating layer. More interestingly, it is found that the as-prepared superhydrophobic alumina surfaces exhibited high contrast water adhesion. Hierarchical alumina film with nanowire bunches-on-nanopores (WBOP) morphology presents extremely slippery property which can obtain a sliding angle (SA) as low as 1°, nanowire pyramids-on-nanopores (WPOP) structure shows strongly sticky water adhesion with the adhesive ability to support 15 μL inverted water droplet at most. The obtained superhydrophobic alumina surfaces show remarkable mechanical durability even treated by crimping or pressing without impact on the water-repellent performance. Moreover, the created surfaces also show excellent resistivity to ice water, boiling water, high temperature, organic solvent and oil contamination, which could expand their usefulness and efficacy in harsh conditions.

  6. Nanotexturing of polystyrene surface in fluorocarbon plasmas: from sticky to slippery superhydrophobicity.

    PubMed

    Mundo, Rosa Di; Palumbo, Fabio; d'Agostino, Riccardo

    2008-05-06

    In this work plasma etching processes have been studied to roughen and fluorinate polystyrene surface as an easy method to achieve a superhydrophobic slippery character. Radiofrequency discharges have been fed with CF(4)/O(2) mixtures and the effect of the O(2):CF(4) ratio, the input power, and the treatment duration have been investigated in terms of wettability, with focus on sliding performances. For this purpose, surface morphological variations, evaluated by means of scanning electron microscopy and atomic force microscopy, together with the chemical assessment by X-ray photoelectron spectroscopy, have been correlated with water contact angle hysteresis and volume resolved sliding angle measurements. Results indicate that by increasing the height and decreasing the density of the structures formed by etching, within a tailored range, a transition from sticky to slippery superhydrophobicity occurs. A short treatment time (5 min) is sufficient to obtain such an effect, provided that a high power input is utilized. Optimized surfaces show a unaltered transparency to visible light according to the low roughness produced.

  7. Gonotrophic cycle and survivorship of Culex quinquefasciatus (Diptera: Culicidae) using sticky ovitraps in Monterrey, northeastern Mexico.

    PubMed

    Elizondo-Quiroga, Armando; Flores-Suarez, Adriana; Elizondo-Quiroga, Darwin; Ponce-Garcia, Gustavo; Blitvich, Bradley J; Contreras-Cordero, Juan Francisco; Gonzalez-Rojas, Jose Ignacio; Mercado-Hernandez, Roberto; Beaty, Barry J; Fernandez-Salas, Ildefonso

    2006-03-01

    Mark-release-recapture experiments were conducted to determine the length of the gonotrophic cycle and rate of survivorship of Culex quinquefasciatus Say in Monterrey, northeastern Mexico. A total of 2,352 field-caught Cx. quinquefasciatus females were marked and released at 8-12 h postemergence in 2 field trials. Sticky ovitraps were used to recapture marked gravid females. One hundred and ten (4.6%) marked females were recaptured during a 12-day sampling period. Recapture rates for the 2 individual trials were 6.4% and 3.5%. The length of the gonotrophic cycle, calculated as the average time between the initial blood meal and the time of recapture of gravid females, was 2-3 days. The first blood-fed mosquitoes were recaptured on the 2nd day postrelease. Gravid egg-laying females were most commonly recaptured at 2-3 days postfeeding. Daily survival estimates for the 2 release dates were of 0.871 and 0.883, respectively.

  8. Proteomic analysis of papaya (Carica papaya L.) displaying typical sticky disease symptoms.

    PubMed

    Rodrigues, Silas P; Ventura, José A; Aguilar, Clemente; Nakayasu, Ernesto S; Almeida, Igor C; Fernandes, Patricia M B; Zingali, Russolina B

    2011-07-01

    Papaya (Carica papaya L.) hosts the only described laticifer-infecting virus (Papaya meleira virus, PMeV), which is the causal agent of papaya sticky disease. To understand the systemic effects of PMeV in papaya, we conducted a comprehensive proteomic analysis of leaf samples from healthy and diseased plants grown under field conditions. First, a reference 2-DE map was established for proteins from healthy samples. A total of 486 reproducible spots were identified, and MALDI-TOF-MS/MS data identified 275 proteins accounting for 159 distinct proteins from 231 spots that were annotated. Second, the differential expression of proteins from healthy and diseased leaves was determined through parallel experiments, using 2-DE and DIGE followed by MALDI-TOF-MS/MS and LC-IonTrap-MS/MS, respectively. Conventional 2-DE analysis revealed 75 differentially expressed proteins. Of those, 48 proteins were identified, with 26 being upregulated (U) and 22 downregulated (D). In general, metabolism-related proteins were downregulated, and stress-responsive proteins were upregulated. This expression pattern was corroborated by the results of the DIGE analysis, which identified 79 differentially expressed proteins, with 23 identified (17 U and 6 D). Calreticulin and the proteasome subunits 20S and RPT5a were shown to be upregulated during infection by both 2-DE and DIGE analyses. These data may help shed light on plant responses against stresses and viral infections.

  9. Monte Carlo simulations of protein micropatterning in biomembranes: effects of immobile sticky obstacles

    NASA Astrophysics Data System (ADS)

    Arnold, Andreas M.; Sevcsik, Eva; Schütz, Gerhard J.

    2016-09-01

    Single molecule trajectories of lipids and proteins can yield valuable information about the nanoscopic organization of the plasma membrane itself. The interpretation of such trajectories, however, is complicated, as the mobility of molecules can be affected by the presence of immobile obstacles, and the transient binding of the tracers to these obstacles. We have previously developed a micropatterning approach that allows for immobilizing a plasma membrane protein and probing the diffusional behavior of a putative interaction partner in living cells. Here, we provide guidelines on how this micropatterning approach can be extended to quantify interaction parameters between plasma membrane constituents in their natural environment. We simulated a patterned membrane system and evaluated the effect of different surface densities of patterned immobile obstacles on the relative mobility as well as the surface density of diffusing tracers. In the case of inert obstacles, the size of the obstacle can be assessed from its surface density at the percolation threshold, which in turn can be extracted from the diffusion behavior of the tracer. For sticky obstacles, 2D dissociation constants can be determined from the tracer diffusion or surface density.

  10. Effects of tectonics and lithology on long profiles of 16 rivers of the southern Central Massif border between the Aude and the Orb (France)

    NASA Astrophysics Data System (ADS)

    Larue, Jean-Pierre

    2008-01-01

    The analysis of longitudinal profiles of river channels and terraces in the southern Central Massif border, between the Aude and the Orb, allows the detection of anomalies caused by lithology and/or tectonic distortions. The rivers which have abnormally high slope and non-lithological knickzones indicate the main uplifted zones: the Montagne Noire and the Saint-Chinian ridge. A geomorphological and sedimentological analysis of detrital deposits was carried out as a basis for correlating the different formations, reconstructing the palaeodrainage and finding the main uplift and fluvial incision stages. During the Miocene, uplift remains limited as it is shown by the correlative fine deposits in the Languedocian piedmont. The Messinian incision (5.7-5.3 Ma) does not cross the Saint-Chinian ridge. On the other hand, fluvial incision becomes widespread in the Montagne Noire during the Upper Pliocene (3.4-2 Ma) when coarse deposits overlie either the Pliocene clay in the Orb palaeovalley or the Messinian conglomerates at the Cesse outlet. An Upper Pliocene uplift of the Montagne Noire and of the Saint-Chinian ridge is the cause of this incision and also of the diversion of the Cesse towards the Aude. Where the uplift rate was higher than incision rate, knickzones have developed like in the Avant-Monts south-side. The knickzones of lithological origin maintain a strong vertical stability during all the river incision stages. On the other hand, those of tectonic origin or base level lowering record upstream migration and their rate of retreat is controlled by the river discharge. As incision occurs only during the cold/temperate transition periods during the Quaternary, upward erosion slowly migrates (15 km since the Upper Pliocene, on the Orb) and so does not reach the riverheads.

  11. Management intensity and vegetation complexity affect web-building spiders and their prey.

    PubMed

    Diehl, Eva; Mader, Viktoria L; Wolters, Volkmar; Birkhofer, Klaus

    2013-10-01

    Agricultural management and vegetation complexity affect arthropod diversity and may alter trophic interactions between predators and their prey. Web-building spiders are abundant generalist predators and important natural enemies of pests. We analyzed how management intensity (tillage, cutting of the vegetation, grazing by cattle, and synthetic and organic inputs) and vegetation complexity (plant species richness, vegetation height, coverage, and density) affect rarefied richness and composition of web-building spiders and their prey with respect to prey availability and aphid predation in 12 habitats, ranging from an uncut fallow to a conventionally managed maize field. Spiders and prey from webs were collected manually and the potential prey were quantified using sticky traps. The species richness of web-building spiders and the order richness of prey increased with plant diversity and vegetation coverage. Prey order richness was lower at tilled compared to no-till sites. Hemipterans (primarily aphids) were overrepresented, while dipterans, hymenopterans, and thysanopterans were underrepresented in webs compared to sticky traps. The per spider capture efficiency for aphids was higher at tilled than at no-till sites and decreased with vegetation complexity. After accounting for local densities, 1.8 times more aphids were captured at uncut compared to cut sites. Our results emphasize the functional role of web-building spiders in aphid predation, but suggest negative effects of cutting or harvesting. We conclude that reduced management intensity and increased vegetation complexity help to conserve local invertebrate diversity, and that web-building spiders at sites under low management intensity (e.g., semi-natural habitats) contribute to aphid suppression at the landscape scale.

  12. Micro-optical elements and optical materials of certain spider webs

    NASA Astrophysics Data System (ADS)

    Kane, D. M.; Naidoo, N.; Little, D. J.

    2012-06-01

    Certain spider webs are composed of several types of micro-optical elements made from transparent optical materials. The silks (radial and capture) are almost exclusively protein. The nearly cylindrical silks have diameters in the range 0.1 to several microns and cross-sectional morphology that is cylindrical-multi-layered,.as studied by transmission electron microscopy, The capture threads are coated with aqueous adhesive that also forms into nearly elliptical micro-lenses (adhesive droplets) mounted on the near cylindrical silks. The remaining elements of the web are the cement junctions tying the radial and the capture threads of the web together. These are irregularly shaped platelets. Progress to date on our research characterizing the optical properties and function of these transparent orb webs has been to interpret the reflection and transmission properties of the elements of the web, and the web as a whole, in natural lighting; to evaluate the optical finish of the surface of the silks and capture droplets; and to measure the principal refractive indices of radial silks using new immersion based methods developed for application to micron-sized, curved optical elements. Here we report the principal refractive indices, birefringence, dispersion and morphology of transparent spider silk subject to various chemical treatments. The morphology is measured using TEM. Insight into the physical origin of the refractive index properties will be discussed.

  13. 'Infectious web'.

    PubMed

    Kotra, L P; Ojcius, D M

    2000-12-01

    A comprehensive list of all known bacterial pathogens of humans is now available at various web-sites on the internet. The sites contain hyperlinks to original scientific literature, along with general information on laboratory testing, antibiotic resistance and clinical treatment. More specific sites highlight the fungus Pneumocystic carinii, arguably the main cause of pneumonia in immunosuppressed individuals.

  14. Webbing It.

    ERIC Educational Resources Information Center

    Brandsberg, Jennifer

    1996-01-01

    Provides a quick look at some World Wide Web sites that contain current election year information. Recommends Project Vote Smart, a site with links to online news organizations, the home pages of all presidential candidates, and other political sites. Briefly notes several interactive CD-ROM resources. (MJP)

  15. Web Sitings.

    ERIC Educational Resources Information Center

    Lo, Erika

    2001-01-01

    Presents seven mathematics games, located on the World Wide Web, for elementary students, including: Absurd Math: Pre-Algebra from Another Dimension; The Little Animals Activity Centre; MathDork Game Room (classic video games focusing on algebra); Lemonade Stand (students practice math and business skills); Math Cats (teaches the artistic beauty…

  16. 'Infectious web'.

    PubMed

    Kotra, L P; Ojcius, D M

    2000-07-01

    Infections by Helicobacter pylori are responsible for duodenal and gastric ulcers and are a significant risk factor for the development of gastric adenocarcinoma. H. pylori was discovered in 1983, but many institutes in Canada, Europe, and the United States are already involved in programs to understand and treat the infections, as reflected by the growing number of internet sites devoted to this bacterium. Most AIDS patients and about 20% of children with acute lymphoblastic leukemia develop Pneumocystis carinii pneumoniae. Information on clinical symptoms and treatment, as well as the P. carinii genome sequencing project, are described at several web sites. Students and researchers wishing to understand the correlation between telomere length and AIDS may turn to web sites of the University of Colorado and Washington University School of Medicine for the latest on telomeres and telomerase, and their function in aging and cancer.

  17. Enzyme-Free Amplification by Nano Sticky Balls for Visual Detection of ssDNA/RNA Oligonucleotides.

    PubMed

    Chen, Shan; Chu, Lok Ting; Yeung, Pak Piu; Zhao, Zichen; Bao, Yuanye; Chan, Miu Shan; Lo, Pik Kwan; Chen, Ting-Hsuan

    2015-10-21

    Visual detection of nucleic acids provides simple and rapid screening for infectious diseases or environmental pathogens. However, sensitivity is the current bottleneck, which may require enzymatic amplification for targets in low abundance and make them incompatible with detection at resource-limited sites. Here we report an enzyme-free amplification that provides a sensitive visual detection of ssDNA/RNA oligonucleotides on the basis of nano "sticky balls". When target oligonucleotides are present, magnetic microparticles (MMPs) and gold nanoparticles (AuNPs) were linked together, allowing the collection of AuNPs after magnetic attraction. Subsequently, the collected AuNPs, which carry many oligonucleotides, were used as the sticky balls to link a second pair of MMPs and polymer microparticles (PMPs). Thus, because the magnetic field can attract the MMPs as well as the linked PMPs to the sidewall, the reduction of suspended PMPs yields a change of light transmission visible by the naked eye. Our results demonstrate that the limit of detection is 10 amol for ssDNAs (228 fM in 45 μL) and 75 amol for ssRNAs (1.67 pM in 45 μL). This method is also compatible with the serum environment and detection of a microRNA, miR-155, derived from human breast cancer cells. With significantly improved sensitivity for visual detection, it provides great potential for point-of-care applications at resource-limited sites.

  18. Attentional Selection Can Be Predicted by Reinforcement Learning of Task-relevant Stimulus Features Weighted by Value-independent Stickiness.

    PubMed

    Balcarras, Matthew; Ardid, Salva; Kaping, Daniel; Everling, Stefan; Womelsdorf, Thilo

    2016-02-01

    Attention includes processes that evaluate stimuli relevance, select the most relevant stimulus against less relevant stimuli, and bias choice behavior toward the selected information. It is not clear how these processes interact. Here, we captured these processes in a reinforcement learning framework applied to a feature-based attention task that required macaques to learn and update the value of stimulus features while ignoring nonrelevant sensory features, locations, and action plans. We found that value-based reinforcement learning mechanisms could account for feature-based attentional selection and choice behavior but required a value-independent stickiness selection process to explain selection errors while at asymptotic behavior. By comparing different reinforcement learning schemes, we found that trial-by-trial selections were best predicted by a model that only represents expected values for the task-relevant feature dimension, with nonrelevant stimulus features and action plans having only a marginal influence on covert selections. These findings show that attentional control subprocesses can be described by (1) the reinforcement learning of feature values within a restricted feature space that excludes irrelevant feature dimensions, (2) a stochastic selection process on feature-specific value representations, and (3) value-independent stickiness toward previous feature selections akin to perseveration in the motor domain. We speculate that these three mechanisms are implemented by distinct but interacting brain circuits and that the proposed formal account of feature-based stimulus selection will be important to understand how attentional subprocesses are implemented in primate brain networks.

  19. Properties, characterization, and decay of sticky rice–lime mortars from the Wugang Ming dynasty city wall (China)

    SciTech Connect

    Xiao, Ya; Fu, Xuan; Gu, Haibing; Gao, Feng; Liu, Shaojun

    2014-04-01

    Urgent restoration of the Wugang Ming dynasty city wall brings about the need for a study of the formulation and properties of mortars. In the present paper, mortar samples from the Wugang Ming dynasty city wall were characterized in a combination of sheet polarized light optical microscopy, scanning electron microscopy with X-ray energy dispersive spectrometer, thermogravimetric/differential scanning calorimetry, X-ray powder diffraction, Fourier transform infrared spectroscopy, and inductively coupled plasma emission spectroscopy. Results show that mortars are mainly built up from inorganic calcium carbonate based organic–inorganic hybrid material with a small amount of sticky rice, which plays a crucial role in forming dense and compact microstructure of mortars and effectively hindering penetration of water and air into mortars. Analysis of decayed products shows that the detrimental soluble salts originates from ambient environment. - Highlights: • Mortars used in the Wugang city wall are a calcium carbonate-sticky rice hybrid bonding material. • Carbonation processing is extremely slow due to dense and compact microstructure of mortars. • Decying of mortars results from the appearance of soluble salt from ambient environment.

  20. Differential accumulation of heavy metals by web spiders and ground spiders in an old-field

    SciTech Connect

    Larsen, K.J.; Brewer, S.R.; Taylor, D.H. . Dept. of Zoology)

    1994-03-01

    Accumulation of the heavy metals Cd, Cu, Pb, and Zn by web spiders (orb weavers: Araneidae) and ground spiders was examined in an old-field that had been subjected to 11 years of nutrient enrichment. The study area consistent of six 0.1-ha plots treated from 1978 to 1988 with municipal sewage sludge containing heavy-metal contaminants, urea-phosphate fertilizer, or left as untreated controls. In 1991 and 1992, heavy-metal concentrations in the soil, ground spiders, and web spiders were measured with a flame AA spectrophotometer. Spiders accumulated Cd, Cu, and Zn to concentrations greater than those present in the soil but did not accumulate Pb. Ground spiders contained significantly higher levels of Cd and Cu than web spiders, whereas web spiders contained slightly greater levels of Pb than ground spiders. No trend between spider guilds was apparent for Zn accumulation. To understand the impact of the application of metal-contaminated municipal sludge on ecosystem, the toxicological effects on the biology and behavior of major biotic components in terrestrial food webs must be known.

  1. Fort Sill ORBS Survey.

    ERIC Educational Resources Information Center

    Rosenbluth, Henry; And Others

    The purpose of this evaluation is to provide an understanding of the educational environment at the Fort Sill Indian School and to exert positive influence for change. The Bureau of Indian Affairs (BIA) school's philosophy, goals, administrative management, and staffing are explained. Various aspects of the school program are examined and…

  2. Deep Web video

    SciTech Connect

    None Available

    2009-06-01

    To make the web work better for science, OSTI has developed state-of-the-art technologies and services including a deep web search capability. The deep web includes content in searchable databases available to web users but not accessible by popular search engines, such as Google. This video provides an introduction to the deep web search engine.

  3. Deep Web video

    ScienceCinema

    None Available

    2016-07-12

    To make the web work better for science, OSTI has developed state-of-the-art technologies and services including a deep web search capability. The deep web includes content in searchable databases available to web users but not accessible by popular search engines, such as Google. This video provides an introduction to the deep web search engine.

  4. Evaluation and control of the risk of food borne pathogens and spoilage bacteria present in “Awa-Uirou”, a sticky rice cake containing sweet red bean paste

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential for growth of food poisoning or spoilage bacteria in “Awa-Uirou”, a sticky rice cake containing sweet red bean paste was evaluated. The water activity (aw 0.92) was in the range suitable for the growth of Staphylococcus aureus, Bacillus cereus and Bacillus subtilis. The viable cell cou...

  5. Embodied Agents, E-SQ and Stickiness: Improving Existing Cognitive and Affective Models

    NASA Astrophysics Data System (ADS)

    de Diesbach, Pablo Brice

    This paper synthesizes results from two previous studies of embodied virtual agents on commercial websites. We analyze and criticize the proposed models and discuss the limits of the experimental findings. Results from other important research in the literature are integrated. We also integrate concepts from profound, more business-related, analysis that deepens on the mechanisms of rhetoric in marketing and communication, and the possible role of E-SQ in man-agent interaction. We finally suggest a refined model for the impacts of these agents on web site users, and limits of the improved model are commented.

  6. Disruption of web structure and predatory behavior of a spider by plant-derived chemical defenses of an aposematic aphid.

    PubMed

    Malcolm, S B

    1989-06-01

    Two toxic and bitter-tasting cardenolides (cardiac-active steroids) were sequestered by the brightly colored oleander aphid,Aphis nerii B. de F., from the neotropical milkweed host plantAsclepias curassavica L. After feeding on milkweed-reared aphids, the orb-web spiderZygiella x-notata (Clerck) built severely disrupted webs and attacked fewer nontoxic, control aphids, whereas the webs of spiders fed only nontoxic aphids remained intact. The regularity and size of the prey-trapping area of webs were reduced significantly in proportion to the amount of toxic aphids eaten. The effects of toxic aphids on spider web structure were mimicked by feeding spiders the bitter-tasting cardenolide digitoxin, a cardenolide with similar steroidal structure and pharmacological activity to the two aphid cardenolides. These results show that the well-known effects of psychoactive drugs on spider web structure are more than interesting behavioral assays of drag activity. Similar effects, produced by plant-derived chemicals in the spider's aphid prey, are relevant to the ecology and evolution of interactions between prey defense and predator foraging.

  7. Surface modification of solid-state nanopores for sticky-free translocation of single-stranded DNA.

    PubMed

    Tang, Zhipeng; Lu, Bo; Zhao, Qing; Wang, Jiajun; Luo, Kaifu; Yu, Dapeng

    2014-11-12

    Nanopore technology is one of the most promising approaches for fast and low-cost DNA sequencing application. Single-stranded DNA detection is primary objective in such device, while solid-state nanopores remain less explored than their biological counterparts due to bio-molecule clogging issue caused by surface interaction between DNA and nanopore wall. By surface coating a layer of polyethylene glycol (PEG), solid-state nanopore can achieve long lifetime for single-stranded DNA sticky-free translocation at pH 11.5. Associated with elimination of non-specific binding of molecule, PEG coated nanopore presents new surface characteristic as less hydrophility, lower 1/f noise, and passivated surface charge responsiveness on pH. Meanwhile, conductance blockage of single-stranded DNA is found to be deeper than double-stranded DNA, which can be well described by a string of blobs model for a quasi-equilibrium state polymer in constraint space.

  8. Fabrication of sticky and slippery superhydrophobic surfaces via spin-coating silica nanoparticles onto flat/patterned substrates.

    PubMed

    Cho, Kuan-Hung; Chen, Li-Jen

    2011-11-04

    Silica nanoparticles were spin-coated onto a flat/patterned (regular pillar-like) substrate to enhance the surface roughness. The surface was further modified by a self-assembled fluorosilanated monolayer. The advancing/receding contact angle and sliding angle measurements were performed to determine the wetting behavior of a water droplet on the surface. It is interesting to find that a transition from a Wenzel surface to a sticky superhydrophobic surface is observed due to the spin-coating silica nanoparticles. A slippery superhydrophobic surface can be further obtained after secondary spin-coating with silica nanoparticles to generate a multi-scale roughness structure. The prepared superhydrophobic substrates should be robust for practical applications. The adhesion between the substrate and nanoparticles is also examined and discussed.

  9. Web Mining for Web Image Retrieval.

    ERIC Educational Resources Information Center

    Chen, Zheng; Wenyin, Liu; Zhang, Feng; Li, Mingjing; Zhang, Hongjiang

    2001-01-01

    Presents a prototype system for image retrieval from the Internet using Web mining. Discusses the architecture of the Web image retrieval prototype; document space modeling; user log mining; and image retrieval experiments to evaluate the proposed system. (AEF)

  10. Web Mining: Machine Learning for Web Applications.

    ERIC Educational Resources Information Center

    Chen, Hsinchun; Chau, Michael

    2004-01-01

    Presents an overview of machine learning research and reviews methods used for evaluating machine learning systems. Ways that machine-learning algorithms were used in traditional information retrieval systems in the "pre-Web" era are described, and the field of Web mining and how machine learning has been used in different Web mining…

  11. EPA Web Taxonomy

    EPA Pesticide Factsheets

    EPA's Web Taxonomy is a faceted hierarchical vocabulary used to tag web pages with terms from a controlled vocabulary. Tagging enables search and discovery of EPA's Web based information assests. EPA's Web Taxonomy is being provided in Simple Knowledge Organization System (SKOS) format. SKOS is a standard for sharing and linking knowledge organization systems that promises to make Federal terminology resources more interoperable.

  12. Web data mining

    NASA Astrophysics Data System (ADS)

    Wibonele, Kasanda J.; Zhang, Yanqing

    2002-03-01

    A web data mining system using granular computing and ASP programming is proposed. This is a web based application, which allows web users to submit survey data for many different companies. This survey is a collection of questions that will help these companies develop and improve their business and customer service with their clients by analyzing survey data. This web application allows users to submit data anywhere. All the survey data is collected into a database for further analysis. An administrator of this web application can login to the system and view all the data submitted. This web application resides on a web server, and the database resides on the MS SQL server.

  13. The Inter-Mammary Sticky Roll: A Novel Technique for Securing a Doppler Ultrasonic Probe to the Precordium for Venous Air Embolism Detection

    PubMed Central

    Wali, Arvin R; Gabel, Brandon C; Khalessi, Alexander A; Sang U, Hoi; Drummond, John C

    2016-01-01

    Venous air embolism is a devastating and potentially life-threatening complication that can occur during neurosurgical procedures. We report the development and use of the “inter-mammary sticky roll,” a technique to reliably secure a precordial Doppler ultrasonic probe to the chest wall during neurosurgical cases that require lateral decubitus positioning. We have found that this noninvasive technique is safe, and effectively facilitates a constant Doppler signal with no additional risk to the patient. PMID:27625905

  14. Constraints on the adhesion of viscous threads spun by orb-weaving spiders: the tensile strength of glycoprotein glue exceeds its adhesion.

    PubMed

    Opell, Brent D; Schwend, Harold S; Vito, Stephen T

    2011-07-01

    In this study we tested the hypothesis that a viscous thread releases its hold on a surface because its glycoprotein glue pulls from the surface and not because its elongating droplets break near their attachment to the surface. We compared the values obtained when three species' viscous threads adhered to four smooth surfaces, which differed in their total surface energy and in the proportions of their dispersion and polar energy components. Although water comprised 43-70% of the volume of these viscous droplets, only the dispersion surface energies of test materials and not their polar surface energies impacted thread adhesion. These results support the droplet pull-off hypothesis and are consistent with a previous finding that capillary force contributes little to thread adhesion. Just as a viscous thread's stickiness is constrained by the tensile strength of its supporting axial fibers, our findings suggest that glycoprotein adhesion is constrained by glycoprotein tensile strength.

  15. Sticky-trapping biting midges (Culicoides spp.) alighting on cattle and sheep: effects of trap colour and evidence for host preference.

    PubMed

    Thompson, G M; Jess, S; Gordon, A W; Murchie, A K

    2014-08-01

    Sticky traps were mounted on heifers and sheep to assess Culicoides spp. (Diptera: Ceratopogonidae) host preference. Initially, four coloured 200-cm(2) sticky traps (white, clear, yellow and blue) were attached to the backs of each of ten Friesian heifers that were released into open pasture for 24 h, repeated on six occasions. More Obsoletus group Culicoides were caught on the white and clear traps than on the yellow and blue. Trap position on the right or left flank also affected midge catch, probably due to heifer orientation in the field. Next, six Friesian heifers and six Charollais hoggets each had one clear and one white sticky strap attached to their backs for one 24-h period per week, repeated for 24 weeks. Overall, Obsoletus group Culicoides comprised 91.8% (n = 5, 955) of the midge catch but there was no evidence of host preference, either discounting or including host live weight in the analyses. However, Pulicaris group Culicoides did demonstrate a significant host preference for sheep, providing that the analysis was adjusted for live weight. On heifers, the Pulicaris group comprised 7.5% of biting midges caught, whereas on hoggets, it comprised 12.7%.

  16. Unusual sequence length-dependent gold nanoparticles aggregation of the ssDNA sticky end and its application for enzyme-free and signal amplified colorimetric DNA detection

    NASA Astrophysics Data System (ADS)

    He, Hongfei; Dai, Jianyuan; Duan, Zhijuan; Zheng, Baozhan; Meng, Yan; Guo, Yong; Dan Xiao, A1"/>

    2016-08-01

    It is known that the adsorption of short single-stranded DNA (ssDNA) on unmodified gold nanoparticles (AuNPs) is much faster than that for long ssDNA, and thus leads to length-dependent AuNPs aggregation after addition of salt, the color of the solutions sequentially changed from red to blue in accordance with the increase of ssDNA length. However, we found herein that the ssDNA sticky end of hairpin DNA exhibited a completely different adsorption behavior compared to ssDNA, an inverse blue-to-red color variation was observed in the colloid solution with the increase of sticky end length when the length is within a certain range. This unusual sequence length-dependent AuNPs aggregation might be ascribed to the effect of the stem of hairpin DNA. On the basis of this unique phenomenon and catalytic hairpin assembly (CHA) based signal amplification, a novel AuNPs-based colorimetric DNA assay with picomolar sensitivity and specificity was developed. This unusual sequence length-dependent AuNPs aggregation of the ssDNA sticky end introduces a new direction for the AuNPs-based colorimetric assays.

  17. Evolving dynamic web pages using web mining

    NASA Astrophysics Data System (ADS)

    Menon, Kartik; Dagli, Cihan H.

    2003-08-01

    The heterogeneity and the lack of structure that permeates much of the ever expanding information sources on the WWW makes it difficult for the user to properly and efficiently access different web pages. Different users have different needs from the same web page. It is necessary to train the system to understand the needs and demands of the users. In other words there is a need for efficient and proper web mining. In this paper issues and possible ways of training the system and providing high level of organization for semi structured data available on the web is discussed. Web pages can be evolved based on history of query searches, browsing, links traversed and observation of the user behavior like book marking and time spent on viewing. Fuzzy clustering techniques help in grouping natural users and groups, neural networks, association rules and web traversals patterns help in efficient sequential anaysis based on previous searches and queries by the user. In this paper we analyze web server logs using above mentioned techniques to know more about user interactions. Analyzing these web server logs help to closely understand the user behavior and his/her web access pattern.

  18. Synthesis of flat sticky hydrophobic carbon diamond-like films using atmospheric pressure Ar/CH4 dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Rincón, R.; Hendaoui, A.; de Matos, J.; Chaker, M.

    2016-06-01

    An Ar/CH4 atmospheric pressure dielectric barrier discharge (AP-DBD) was used to synthesize sticky hydrophobic diamond-like carbon (DLC) films on glass surface. The film is formed with plasma treatment duration shorter than 30 s, and water contact angles larger than 90° together with contact angle hysteresis larger than 10° can be achieved. According to Fourier transform infrared spectroscopy and atomic force microscopy analysis, hydrocarbon functional groups are created on the glass substrate, producing coatings with low surface energy (˜35 mJ m-2) with no modification of the surface roughness. To infer the plasma processes leading to the formation of low energy DLC surfaces, optical emission spectroscopy was used. From the results, a direct relationship between the CH species present in the plasma and the carbon concentration in the hydrophobic layer was found, which suggests that the CH species are the precursors of DLC film growth. Additionally, the plasma gas temperature was measured to be below 350 K which highlights the suitability of using AP-DBD to treat thermo-sensitive surfaces.

  19. Influence of Sticky Rice and Anionic Polyacrylamide on the Crystallization of Calcium Carbonate in Chinese Organic Sanhetu

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Peng, Changsheng; Dai, Min; Gu, Qingbao; Song, Shaoxian

    2015-09-01

    The crystallization of calcium carbonate (CaCO3) in soil controlled by natural organic material was considered a very important reason to enhance the property of ancient Chinese organic Sanhetu (COS), but how the organic material affected the crystallization of CaCO3 in COS is still unclear. In this paper, a natural organic material (sticky rice, SR) and a synthetic organic material (anionic polyacrylamide, APAM) were selected as additives to investigate their effect on the crystallization of CaCO3. The experimental results showed that the morphology and size of CaCO3 crystals could be affected by the concentration of additives and reaction time, while only the size of CaCO3 crystals could be affected by the concentration of reactant. Although the morphology and size of CaCO3 crystals varied greatly with the variation of additive concentration, reactant concentration and reaction time, the polymorph of CaCO3 crystals were always calcite, according to SEM/EDX, XRD and FTIR analyses. This study may help us to better understand the mechanism of the influence of organic materials on CaCO3 crystallization and properties of COS.

  20. An Acinetobacter trimeric autotransporter adhesin reaped from cells exhibits its nonspecific stickiness via a highly stable 3D structure

    PubMed Central

    Yoshimoto, Shogo; Nakatani, Hajime; Iwasaki, Keita; Hori, Katsutoshi

    2016-01-01

    Trimeric autotransporter adhesins (TAAs), cell surface proteins of Gram-negative bacteria, mediate bacterial adhesion to host cells and extracellular matrix proteins. However, AtaA, a TAA in the nonpathogenic Acinetobacter sp. strain Tol 5, shows nonspecific, high adhesiveness to abiotic material surfaces as well as to biotic surfaces. AtaA is a homotrimer of polypeptides comprising 3,630 amino acids and forms long nanofibers; therefore, it is too large and structurally complex to be produced as a recombinant protein. In this study, we isolated AtaA’s passenger domain (AtaA PSD), which is translocated to the cell surface through the C-terminal transmembrane domain and exhibits biological functions, using a new method. We introduced a protease recognition site and reaped AtaA nanofibers 225 nm in length from the cell surface through proteolytic cleavage with a specific protease. Biochemical and biophysical analyses of the purified native AtaA PSD revealed that it has a stable structure under alkaline and acidic conditions. Temperatures above 80 °C, which disrupted AtaA’s higher-order structure but maintained the full-length AtaA polypeptide, inactivated AtaA’s nonspecific adhesiveness, suggesting that the stickiness of AtaA requires its 3D structure. This finding refutes the widespread but vague speculation that large unfolded polypeptides readily stick to various surfaces. PMID:27305955

  1. Label-free quantitative proteomics reveals differentially regulated proteins in the latex of sticky diseased Carica papaya L. plants.

    PubMed

    Rodrigues, Silas P; Ventura, José A; Aguilar, Clemente; Nakayasu, Ernesto S; Choi, HyungWon; Sobreira, Tiago J P; Nohara, Lilian L; Wermelinger, Luciana S; Almeida, Igor C; Zingali, Russolina B; Fernandes, Patricia M B

    2012-06-18

    Papaya meleira virus (PMeV) is so far the only described laticifer-infecting virus, the causal agent of papaya (Carica papaya L.) sticky disease. The effects of PMeV on the laticifers' regulatory network were addressed here through the proteomic analysis of papaya latex. Using both 1-DE- and 1D-LC-ESI-MS/MS, 160 unique papaya latex proteins were identified, representing 122 new proteins in the latex of this plant. Quantitative analysis by normalized spectral counting revealed 10 down-regulated proteins in the latex of diseased plants, 9 cysteine proteases (chymopapain) and 1 latex serine proteinase inhibitor. A repression of papaya latex proteolytic activity during PMeV infection was hypothesized. This was further confirmed by enzymatic assays that showed a reduction of cysteine-protease-associated proteolytic activity in the diseased papaya latex. These findings are discussed in the context of plant responses against pathogens and may greatly contribute to understand the roles of laticifers in plant stress responses.

  2. Attention focusing in a sit-and-wait forager: a spider controls its prey-detection ability in different web sectors by adjusting thread tension.

    PubMed

    Nakata, Kensuke

    2010-01-07

    Focusing attention is a way for animals to search for and to obtain food efficiently. This study examines whether a sit-and-wait forager, the orb-web spider Cyclosa octotuberculata, focuses its attention on limited foraging areas. Video records of foraging activity revealed that the spiders detected prey trapped in the west and east sectors of their web less frequently than prey trapped in the north and south sectors. Comparison of photos of the web hub area with and without spiders present revealed that the spiders pulled radii towards the centre when waiting for prey. Radius pulling is stronger in the north and south web sectors than in the west and east sectors, possibly causing more tension in radii running vertically. Experimental manipulation indicated that the spiders responded to prey quicker when thread tension was increased. The results suggest that C. octotuberculata focus their attention on the web areas above and below the spider by adjusting the tension in web threads; and this causes higher prey detection rates in these areas.

  3. Detection of olive oil mill waste (OOMW) disposal areas using high resolution GeoEye's OrbView-3 and Google Earth images

    NASA Astrophysics Data System (ADS)

    Agapiou, Athos; Papadopoulos, Nikos; Sarris, Apostolos

    2016-01-01

    The olive oil industry is considered to be as one of the driving sectors of the agricultural economy of the Mediterranean basin. The extraction of olive oil generates huge quantities of wastes that may have a great impact on land and water environments due to high concentrations in phenolic compounds that could cause ophytotoxicity. This paper aims to examine the potential use of freely distributed satellite images for the detection of olive oil mil waste (OOMW) areas in the island of Crete through the use of two cases studies. In the first case study an archive GeoEye OrbView-3 image was used to detect OOMW areas using the Spectral Angle Mapper detection algorithm and other geometric and topographic parameters. In the second case study, Google Earth images were examined through different classification algorithms at different scales. The overall results demonstrate that remote sensing techniques can be used as an alternative to field observations so as to detect and monitor OOMW areas Furthermore, freely distributed RGB images from digital globes (such as Google Earth) can be sufficiently and effectively used for this purpose.

  4. JPL web team

    NASA Technical Reports Server (NTRS)

    Bickler, D. B.

    1986-01-01

    The Jet Propulsion Laboratory (JPL) WEB Team activities were reported for activities which were directed toward identifying and attacking areas in the growth of dendritic web ribbon, to complement the program at Westinghouse Electric Corp.

  5. Trilinos Web Interface Package

    SciTech Connect

    Hu, Jonathan; Phenow, Michael N.; Sala, Marzio; Tuminaro, Ray S.

    2006-09-01

    WebTrilinos is a scientific portal, a web-based environment to use several Trilinos packages through the web. If you are a teaching sparse linear algebra, you can use WebTrilinos to present code snippets and simple scripts, and let the students execute them from their browsers. If you want to test linear algebra solvers, you can use the MatrixPortal module, and you just have to select problems and options, then plot the results in nice graphs.

  6. Multimedia Web Searching Trends.

    ERIC Educational Resources Information Center

    Ozmutlu, Seda; Spink, Amanda; Ozmutlu, H. Cenk

    2002-01-01

    Examines and compares multimedia Web searching by Excite and FAST search engine users in 2001. Highlights include audio and video queries; time spent on searches; terms per query; ranking of the most frequently used terms; and differences in Web search behaviors of U.S. and European Web users. (Author/LRW)

  7. Evaluating Web Usability

    ERIC Educational Resources Information Center

    Snider, Jean; Martin, Florence

    2012-01-01

    Web usability focuses on design elements and processes that make web pages easy to use. A website for college students was evaluated for underutilization. One-on-one testing, focus groups, web analytics, peer university review and marketing focus group and demographic data were utilized to conduct usability evaluation. The results indicated that…

  8. Commercial Web Site Links.

    ERIC Educational Resources Information Center

    Thelwall, Mike

    2001-01-01

    Discusses business use of the Web and related search engine design issues as well as research on general and academic links before reporting on a survey of the links published by a collection of business Web sites. Results indicate around 66% of Web sites do carry external links, most of which are targeted at a specific purpose, but about 17%…

  9. Implementing Good Web Style.

    ERIC Educational Resources Information Center

    Plankis, Brian J.

    1998-01-01

    Provides an overview of Web-site design and discusses three steps in building a site: audience analysis, design, and evaluation. Includes an analysis of loading speeds with and without graphics; examples of no-style, low-bandwidth, and high-bandwidth Web sites; and addresses for related Web sites. (PEN)

  10. WWW: Neuroscience Web Sites

    ERIC Educational Resources Information Center

    Liu, Dennis

    2006-01-01

    The human brain contains an estimated 100 billion neurons, and browsing the Web, one might be led to believe that there's a Web site for every one of those cells. It's no surprise that there are lots of Web sites concerning the nervous system. After all, the human brain is toward the top of nearly everyone's list of favorite organs and of…

  11. Small-scale spatial pattern of web-building spiders (Araneae) in alfalfa: relationship to disturbance from cutting, prey availability, and intraguild interactions.

    PubMed

    Birkhofer, Klaus; Scheu, Stefan; Wise, David H

    2007-08-01

    Understanding the development of spatial patterns in generalist predators will improve our ability to incorporate them into biological control programs. We studied the small-scale spatial patterns of spider webs in alfalfa by analyzing the relationship between web locations over distances ranging from 4 to 66 cm. Using a coordinate-based spatial statistic (O-ring) and assuming a heterogeneous distribution of suitable web sites, we analyzed the impact of cutting and changes in spider abundance on web distribution. We analyzed the influence of small-scale variation in prey availability by comparing web distributions to the pattern of sticky-trap captures of Aphididae and Diptera described by a count-based spatial statistic (SADIE). Cutting of alfalfa reduced the overall density of web-building spiders but had no immediate impact on the spatial distribution of their webs. Availability of aphids was highest before the alfalfa was cut and was clumped at a scale of 66 cm. Spider webs, however, were not clumped at any scale or date. In contrast, webs were regularly distributed at smaller distances (<20 cm) immediately before and after cutting. Because cursorial and web-building spiders were most active during this period, we hypothesize that the development of small-scale regularity in web locations was driven by intraguild interactions. Our results suggest that intraguild interactions contribute to the development of small-scale spatial patterns of spider webs in alfalfa. Variation in prey availability may have more of an influence on web distribution in crops with a different vegetation structure or if patterns are studied at larger spatial scales.

  12. Effects of hydrolysis on solid-state relaxation and stickiness behavior of sodium caseinate-lactose powders.

    PubMed

    Mounsey, J S; Hogan, S A; Murray, B A; O'Callaghan, D J

    2012-05-01

    Hydrolyzed or nonhydrolyzed sodium caseinate-lactose dispersions were spray dried, at a protein: lactose ratio of 0.5, to examine the effects of protein hydrolysis on relaxation behavior and stickiness of model powders. Sodium caseinate (NC) used included a nonhydrolyzed control (DH 0) and 2 hydrolyzed variants (DH 8.3 and DH 15), where DH = degree of hydrolysis (%). Prior to spray drying, apparent viscosities of liquid feeds (at 70°C) at a shear rate of 20/s were 37.6, 3.14, and 3.19 mPa·s, respectively, for DH 0, DH 8, and DH 15 dispersions. Powders containing hydrolyzed casein were more susceptible to sticking than those containing intact NC. The former had also lower bulk densities and powder particle sizes. Scanning electron microscopy showed that hydrolyzed powders had thinner particle walls and were more friable than powders containing intact NC. Secondary structure of caseinates, determined by Fourier transform infrared spectroscopy, was affected by the relative humidity of storage and the presence of lactose as co-solvent rather than its physical state. Glass transition temperatures and lactose crystallization temperatures, determined by differential scanning calorimetry were not affected by caseinate hydrolysis, although the effects of protein hydrolysis on glass-rubber transitions (T(gr)) could be determined by thermo-mechanical analysis. Powders containing hydrolyzed NC had lower T(gr) values (~30°C) following storage at a higher subcrystallization relative humidity (33%) compared with powder with nonhydrolyzed NC (T(gr) value of ~40°C), an effect that reflects more extensive plasticization of powder matrices by moisture. Results support that sodium caseinate-lactose interactions were weak but that relaxation behavior, as determined by the susceptibility of powder to sticking, was affected by hydrolysis of sodium caseinate.

  13. Isolation and purification of Flavobacterium alpha-1,3-glucanase-hydrolyzing, insoluble, sticky glucan of Streptococcus mutans.

    PubMed Central

    Ebisu, S; Kato, K; Kotani, S; Misaki, A

    1975-01-01

    Studies were made on the physical and chemical properties of polysaccharides synthesized by cell-free extracts of Streptococcus mutans, Streptococcus sanguis, and Streptococcus sp. and their susceptibilities to dextranases. Among the polysaccharides examined, insoluble glucans were rather resistant to available dextranase preparations, and the insoluble, sticky glucan produced by S. mutans OMZ 176, which could be important in formation of dental plaques, was the most resistant. By enrichment culture of soil specimens, using OMZ 176 glucans as the sole carbon source, an organism was isolated that produced colonies surrounded by a clear lytic zone on opaque agar plates containing the OMZ 176 glucan. The organism was identified as a strain of Flavobacterium and named the Ek-14 bacterium. EK-14 bacterium was grown in Trypticase soy broth, and an enzyme capable of hydrolyzing the OMZ 176 glucan was concentrated from the culture supernatant and purified by negative adsorption on a diethylaminoethyl-cellulose (DE-32) column and gradient elution chromatography with a carboxymethyl-cellulose (CM-32) column. The enzyme was a basic protein with an isoelectric point of pH 8.5 and molecular weight of 65,000. Its optimum pH was 6.3 and its optimal temperature was 42 C. The purified enzyme released 11% of the total glucose residues of the OMZ 176 glucan as reducing sugars and solubilized about half of the substrate glucan. The products were found to be isomaltose, nigerose, and nigerotriose, with some oligosaccharides. The purified enzyme split the alpha-1,3-glucan endolytically and was inactive toward glucans containing alpha-1,6, alpha-1,4, beta-1,3, beta-1,4, and/or beta-1,6 bonds as the main linkages. Images PMID:370

  14. Web-based tools for real-time assessment of Earthscope's Transportable Array state-of- health: integration of the Antelope Real Time System, RRDtool, AJAX and PHP

    NASA Astrophysics Data System (ADS)

    Newman, R. L.; Lindquist, K. G.; Vernon, F. L.; Davis, G. A.; Eakins, J.; Astiz, L.

    2007-05-01

    Over the past three years the Array Network Facility (ANF) has developed a robust, extensible web-based toolkit for monitoring the state-of-health of Earthscope's Transportable Array. The tools are constructed within a framework of the Antelope Real Time System (ARTS) and the Antelope interface to the PHP Hypertext Processor (PHP), an inline scripting language. Exporting data from Datascope databases and Object Ring Buffer (ORB) packets into XML allows comprehensive client-side interaction via Asynchronous Javascript And XML (AJAX) calls. Navigating and displaying the resultant XML Document Object Model (DOM) trees are done using eXtensible Stylesheet Language Transformation (XSLT) and PHP's built-in DOM classes. Tools include regional and individual station and event maps, state-of-health statistics, waveform plots, and datalogger monitoring. Combined with real-time graphing of state-of-health parameters from status ORB packets using Round Robin Database Tool (RRDtool), this toolkit allows analysts, station engineers, scientists, and the general public to view, assess, interact with, and download data collected from the 250+ stations in the Transportable Array seismic network. Tools are available at the Array Network Facility website, http:anf.ucsd.edu.

  15. Drying of fiber webs

    DOEpatents

    Warren, David W.

    1997-01-01

    A process and an apparatus for high-intensity drying of fiber webs or sheets, such as newsprint, printing and writing papers, packaging paper, and paperboard or linerboard, as they are formed on a paper machine. The invention uses direct contact between the wet fiber web or sheet and various molten heat transfer fluids, such as liquified eutectic metal alloys, to impart heat at high rates over prolonged durations, in order to achieve ambient boiling of moisture contained within the web. The molten fluid contact process causes steam vapor to emanate from the web surface, without dilution by ambient air; and it is differentiated from the evaporative drying techniques of the prior industrial art, which depend on the uses of steam-heated cylinders to supply heat to the paper web surface, and ambient air to carry away moisture, which is evaporated from the web surface. Contact between the wet fiber web and the molten fluid can be accomplished either by submersing the web within a molten bath or by coating the surface of the web with the molten media. Because of the high interfacial surface tension between the molten media and the cellulose fiber comprising the paper web, the molten media does not appreciately stick to the paper after it is dried. Steam generated from the paper web is collected and condensed without dilution by ambient air to allow heat recovery at significantly higher temperature levels than attainable in evaporative dryers.

  16. Drying of fiber webs

    DOEpatents

    Warren, D.W.

    1997-04-15

    A process and an apparatus are disclosed for high-intensity drying of fiber webs or sheets, such as newsprint, printing and writing papers, packaging paper, and paperboard or linerboard, as they are formed on a paper machine. The invention uses direct contact between the wet fiber web or sheet and various molten heat transfer fluids, such as liquefied eutectic metal alloys, to impart heat at high rates over prolonged durations, in order to achieve ambient boiling of moisture contained within the web. The molten fluid contact process causes steam vapor to emanate from the web surface, without dilution by ambient air; and it is differentiated from the evaporative drying techniques of the prior industrial art, which depend on the uses of steam-heated cylinders to supply heat to the paper web surface, and ambient air to carry away moisture, which is evaporated from the web surface. Contact between the wet fiber web and the molten fluid can be accomplished either by submersing the web within a molten bath or by coating the surface of the web with the molten media. Because of the high interfacial surface tension between the molten media and the cellulose fiber comprising the paper web, the molten media does not appreciatively stick to the paper after it is dried. Steam generated from the paper web is collected and condensed without dilution by ambient air to allow heat recovery at significantly higher temperature levels than attainable in evaporative dryers. 6 figs.

  17. Integrating Land Conservation and Renewable Energy Goals in California: Assessing Land Use and Economic Cost Impacts Using the Optimal Renewable Energy Build-Out (ORB) Model.

    NASA Astrophysics Data System (ADS)

    Wu, G. C.; Schlag, N. H.; Cameron, D. R.; Brand, E.; Crane, L.; Williams, J.; Price, S.; Hernandez, R. R.; Torn, M. S.

    2015-12-01

    There is a lack of understanding of the environmental impacts and economic costs of potential renewable energy (RE) siting decisions that achieve ambitious RE targets. Such analyses are needed to inform policy recommendations that minimize potential conflicts between conservation and RE development. We use the state of California's rapid development of utility-scale RE as a case study to examine how possible land use constraints impact the total electricity land area, areas with conservation value, water use, and electricity cost of ambitious RE portfolios. We developed the Optimal Renewable energy Build-out (ORB) model, and used it in conjunction with the Renewable Portfolio Standard (RPS) Calculator, a RE procurement and transmission planning tool used by utilities within California, to generate environmentally constrained renewable energy potential and assess the cost and siting-associated impacts of wind, solar photovoltaic, concentrating solar power (CSP), and geothermal technologies. We find that imposing environmental constraints on RE development achieves lower conservation impacts and results in development of more fragmented land areas. With increased RE and environmental exclusions, generation becomes more widely distributed across the state, which results in more development on herbaceous agricultural vegetation, grasslands, and developed & urban land cover types. We find land use efficiencies of RE technologies are relatively inelastic to changes in environmental constraints, suggesting that cost-effective substitutions that reduce environmental impact and achieve RE goals is possible under most scenarios and exclusion categories. At very high RE penetration that is limited to in-state development, cost effectiveness decreases substantially under the highest level of environmental constraint due to the over-reliance on solar technologies. This additional cost is removed once the in-state constraint is lifted, suggesting that minimizing both negative

  18. Self-assembly and glass-formation in a lattice model of telechelic polymer melts: Influence of stiffness of the sticky bonds.

    PubMed

    Xu, Wen-Sheng; Freed, Karl F

    2016-06-07

    Telechelic polymers are chain macromolecules that may self-assemble through the association of their two mono-functional end groups (called "stickers"). A deep understanding of the relation between microscopic molecular details and the macroscopic physical properties of telechelic polymers is important in guiding the rational design of telechelic polymer materials with desired properties. The lattice cluster theory (LCT) for strongly interacting, self-assembling telechelic polymers provides a theoretical tool that enables establishing the connections between important microscopic molecular details of self-assembling polymers and their bulk thermodynamics. The original LCT for self-assembly of telechelic polymers considers a model of fully flexible linear chains [J. Dudowicz and K. F. Freed, J. Chem. Phys. 136, 064902 (2012)], while our recent work introduces a significant improvement to the LCT by including a description of chain semiflexibility for the bonds within each individual telechelic chain [W.-S. Xu and K. F. Freed, J. Chem. Phys. 143, 024901 (2015)], but the physically associative (or called "sticky") bonds between the ends of the telechelics are left as fully flexible. Motivated by the ubiquitous presence of steric constraints on the association of real telechelic polymers that impart an additional degree of bond stiffness (or rigidity), the present paper further extends the LCT to permit the sticky bonds to be semiflexible but to have a stiffness differing from that within each telechelic chain. An analytical expression for the Helmholtz free energy is provided for this model of linear telechelic polymer melts, and illustrative calculations demonstrate the significant influence of the stiffness of the sticky bonds on the self-assembly and thermodynamics of telechelic polymers. A brief discussion is also provided for the impact of self-assembly on glass-formation by combining the LCT description for this extended model of telechelic polymers with the

  19. Using Open Web APIs in Teaching Web Mining

    ERIC Educational Resources Information Center

    Chen, Hsinchun; Li, Xin; Chau, M.; Ho, Yi-Jen; Tseng, Chunju

    2009-01-01

    With the advent of the World Wide Web, many business applications that utilize data mining and text mining techniques to extract useful business information on the Web have evolved from Web searching to Web mining. It is important for students to acquire knowledge and hands-on experience in Web mining during their education in information systems…

  20. Sign language Web pages.

    PubMed

    Fels, Deborah I; Richards, Jan; Hardman, Jim; Lee, Daniel G

    2006-01-01

    The WORLD WIDE WEB has changed the way people interact. It has also become an important equalizer of information access for many social sectors. However, for many people, including some sign language users, Web accessing can be difficult. For some, it not only presents another barrier to overcome but has left them without cultural equality. The present article describes a system that allows sign language-only Web pages to be created and linked through a video-based technique called sign-linking. In two studies, 14 Deaf participants examined two iterations of signlinked Web pages to gauge the usability and learnability of a signing Web page interface. The first study indicated that signing Web pages were usable by sign language users but that some interface features required improvement. The second study showed increased usability for those features; users consequently couldnavigate sign language information with ease and pleasure.

  1. WebEAV

    PubMed Central

    Nadkarni, Prakash M.; Brandt, Cynthia M.; Marenco, Luis

    2000-01-01

    The task of creating and maintaining a front end to a large institutional entity-attribute-value (EAV) database can be cumbersome when using traditional client-server technology. Switching to Web technology as a delivery vehicle solves some of these problems but introduces others. In particular, Web development environments tend to be primitive, and many features that client-server developers take for granted are missing. WebEAV is a generic framework for Web development that is intended to streamline the process of Web application development for databases having a significant EAV component. It also addresses some challenging user interface issues that arise when any complex system is created. The authors describe the architecture of WebEAV and provide an overview of its features with suitable examples. PMID:10887163

  2. Building Community Web Platform

    NASA Astrophysics Data System (ADS)

    Ohmukai, Ikki; Matsuo, Yutaka; Matsumura, Naohiro; Takeda, Hideaki

    In this paper we propose Web-based communication environment called ``Community Web Platform''. Our platform provides an easy way to exchange personal knowledge among people with lightweight metadata such like RSS and FOAF. We investigate the nature of ``personal trustness'' on the environment since it is one and only measure for evaluating subjective information and knowledge. We also discuss how to develop and maintain Community Web applications from our exrerience.

  3. Properties of food webs

    SciTech Connect

    Pimm, S.L.

    1980-04-01

    On the assumption that systems of interacting species, when perturbed from equilibrium, should return to equilibrium quickly, one can predict four properties of food webs: (1) food chains should be short, (2) species feeding on more than one trophic level (omnivores) should be rare, (3) those species that do feed on more than one trophic level should do so by feeding on species in adjacent trophic levels, and (4) host-parasitoid systems are likely to be exceptions to (1)-(3) when interaction coefficients permit greater trophic complexity. By generating random, model food webs (with many features identical to webs described from a variety of marine, freshwater, and terrestrial systems), it is possible to generate expected values for the number of trophic levels and the degree of omnivory within webs. When compared with these random webs, real world webs are shown to have fewer trophic levels, less omnivory, and very few omnivores feeding on nonadjacent trophic levels. Insect webs are shown to have a greater degree of omnivory than other webs. The confirmation of all these predictions from stability analyses suggests that system stability places necessary, though not sufficient, limitations on the possible shapes of food webs.

  4. Web Accessibility and Guidelines

    NASA Astrophysics Data System (ADS)

    Harper, Simon; Yesilada, Yeliz

    Access to, and movement around, complex online environments, of which the World Wide Web (Web) is the most popular example, has long been considered an important and major issue in the Web design and usability field. The commonly used slang phrase ‘surfing the Web’ implies rapid and free access, pointing to its importance among designers and users alike. It has also been long established that this potentially complex and difficult access is further complicated, and becomes neither rapid nor free, if the user is disabled. There are millions of people who have disabilities that affect their use of the Web. Web accessibility aims to help these people to perceive, understand, navigate, and interact with, as well as contribute to, the Web, and thereby the society in general. This accessibility is, in part, facilitated by the Web Content Accessibility Guidelines (WCAG) currently moving from version one to two. These guidelines are intended to encourage designers to make sure their sites conform to specifications, and in that conformance enable the assistive technologies of disabled users to better interact with the page content. In this way, it was hoped that accessibility could be supported. While this is in part true, guidelines do not solve all problems and the new WCAG version two guidelines are surrounded by controversy and intrigue. This chapter aims to establish the published literature related to Web accessibility and Web accessibility guidelines, and discuss limitations of the current guidelines and future directions.

  5. Silicon Web Process Development

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.; Seidensticker, R. G.; Hopkins, R. H.; Mchugh, J. P.; Hill, F. E.; Heimlich, M. E.; Driggers, J. M.

    1978-01-01

    Progress in the development of techniques to grow silicon web at 25 wq cm/min output rate is reported. Feasibility of web growth with simultaneous melt replenishment is discussed. Other factors covered include: (1) tests of aftertrimmers to improve web width; (2) evaluation of growth lid designs to raise speed and output rate; (3) tests of melt replenishment hardware; and (4) investigation of directed gas flow systems to control unwanted oxide deposition in the system and to improve convective cooling of the web. Compatibility with sufficient solar cell performance is emphasized.

  6. Web 2.0

    NASA Astrophysics Data System (ADS)

    Gibson, Becky

    The Web is growing and changing from a paradigm of static publishing to one of participation and interaction. This change has implications for people with disabilities who rely on access to the Web for employment, information, entertainment, and increased independence. The interactive and collaborative nature of Web 2.0 can present access problems for some users. There are some best practices which can be put in place today to improve access. New specifications such as Accessible Rich Internet Applications (ARIA) and IAccessible2 are opening the doors to increasing the accessibility of Web 2.0 and beyond.

  7. An introduction to webs

    NASA Astrophysics Data System (ADS)

    White, C. D.

    2016-04-01

    Webs are sets of Feynman diagrams that contribute to the exponents of scattering amplitudes, in the kinematic limit in which emitted radiation is soft. As such, they have a number of phenomenological and formal applications, and offer tantalizing glimpses into the all-order structure of perturbative quantum field theory. This article is based on a series of lectures given to graduate students, and aims to provide a pedagogical introduction to webs. Topics covered include exponentiation in (non-)abelian gauge theories, the web mixing matrix formalism for non-abelian gauge theories, and recent progress on the calculation of web diagrams. Problems are included throughout the text, to aid understanding.

  8. Motivation Mining: Prospecting the Web.

    ERIC Educational Resources Information Center

    Small, Ruth V.; Arnone, Marilyn P.

    1999-01-01

    Describes WebMAC instruments, which differ from other Web-evaluation instruments because they have a theoretical base, are user-centered, are designed for students in grades 7 through 12, and assess the motivational quality of Web sites. Examples are given of uses of WebMAC Middle and WebMAC Senior in activities to promote evaluation and…

  9. Bloch points are sticky

    NASA Astrophysics Data System (ADS)

    Tchernyshyov, Oleg; Kim, Se Kwon

    2014-03-01

    Bloch points are zero-dimensional topological defects in three-dimensional ferromagnets. A representative magnetic configuration is a hedgehog with magnetization pointing away from a center. The singular nature of a Bloch point's core leads to interesting and observable consequences. A simple argument based on dimensional analysis shows that a magnetic lattice creates a periodic potential that can pin a Bloch point even if the lattice has no defects. The pinning force is of the order of the micromagnetic exchange constant, a few piconewtons in a typical ferromagnet. A domain wall in a cylindrical ferromagnetic wire with the diameter of a few tens of nanometers may contain a Bloch point. Such a domain wall will have a sizable depinning field, tens of oersteds. A Bloch point moving through an atomic lattice should emit electromagnetic waves at the frequency of a few hundred gigahertz. Research supported in part by the U.S. National Science Foundation under Grants No. DMR-0520491 and No. DMR-1104753.

  10. Water: A Sticky Subject?

    ERIC Educational Resources Information Center

    McCarty, Robbie V.

    2000-01-01

    Introduces an activity for fifth grade elementary students on water, cohesion, and adhesion. Provides a list of necessary materials and includes a checklist for performance based assessment. Recommends follow up experiments for testing cohesive property with different liquids. (YDS)

  11. Creating a Sticky MOOC

    ERIC Educational Resources Information Center

    Oakley, Barbara; Poole, Debra; Nestor, MaryAnne

    2016-01-01

    "Learning How to Learn," a MOOC from UC San Diego, is one of Coursera's most successful offerings; in its first year, nearly one million learners enrolled in the course. As a result of its high student satisfaction levels (4.55 on a 5-point Likert scale) and the persistence of strong student interest in the course, it is worth examining…

  12. Advancement's Sticky Issues

    ERIC Educational Resources Information Center

    Jackson, Patricia

    2011-01-01

    The author did not expect to be surprised or disturbed by the data from the latest Council for Advancement and Support of Education (CASE) salary survey; however, she was. CASE has been conducting the survey since 1982, so she assumed the findings would mirror her own salary history and those of her peers. While she suspected that older women…

  13. Web 2 Nowhere?

    ERIC Educational Resources Information Center

    Shapiro, Steven

    2012-01-01

    Web 2.0 seems to be all the rage these days. One cannot go to a library conference and attend presentations or stroll down the halls without hearing some mention of it in magical tones reserved for some great discovery. The excitement surrounding Web 2.0 reminds the author of the frenzy that gripped the country between 1848 and 1855, when…

  14. Taming the Tangled Web.

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2001-01-01

    Describes the Open Knowledge Initiative (OKI) and its use as a resource for higher education institutions interested in developing web-based learning capabilities. Highlights the OKI collaborative effort and its goal to ensure that the web tools it designs are installable and supportable on smaller campuses and by smaller institutions. (GR)

  15. Wetlands and Web Pages.

    ERIC Educational Resources Information Center

    Tisone-Bartels, Dede

    1998-01-01

    Argues that the preservation of areas like the Shoreline Park (California) wetlands depends on educating students about the value of natural resources. Describes the creation of a Web page on the wetlands for third-grade students by seventh-grade art and ecology students. Outlines the technical process of developing a Web page. (DSK)

  16. Rhizoctonia web blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia web blight, caused by several Rhizoctonia spp., is an important disease of evergreen azaleas and other ornamental plants in nurseries. The primary pathogens causing web blight are binucleate Rhizoctonia anastomosis groups (AG) (= Ceratobasidium D.P. Rogers, teleomorph). In southern AL an...

  17. The Social Web

    ERIC Educational Resources Information Center

    Richardson, Will

    2006-01-01

    This article takes a look at tech guru Will Richardson's new book, "Blogs, Wikis, Podcasts, and Other Powerful Web Tools for Classrooms." Whether it's blogs or wikis or RSS, all roads now point to a Web where little is done in isolation. The biggest, most sweeping change in the people's relationship with the Internet may not be as much the ability…

  18. Web Page Design.

    ERIC Educational Resources Information Center

    Lindsay, Lorin

    Designing a web home page involves many decisions that affect how the page will look, the kind of technology required to use the page, the links the page will provide, and kinds of patrons who can use the page. The theme of information literacy needs to be built into every web page; users need to be taught the skills of sorting and applying…

  19. Web Publishing Schedule

    EPA Pesticide Factsheets

    Section 207(f)(2) of the E-Gov Act requires federal agencies to develop an inventory and establish a schedule of information to be published on their Web sites, make those schedules available for public comment. To post the schedules on the web site.

  20. Sign Language Web Pages

    ERIC Educational Resources Information Center

    Fels, Deborah I.; Richards, Jan; Hardman, Jim; Lee, Daniel G.

    2006-01-01

    The World Wide Web has changed the way people interact. It has also become an important equalizer of information access for many social sectors. However, for many people, including some sign language users, Web accessing can be difficult. For some, it not only presents another barrier to overcome but has left them without cultural equality. The…

  1. Literature on the Web.

    ERIC Educational Resources Information Center

    Deal, Nancy

    2003-01-01

    A teacher in the English education program at Buffalo State College describes her development of Web-based literature guides for preservice teachers to use in preparation and student teaching and for secondary-level English/language arts teachers to use in their classrooms. Discusses assembling materials for the web guide; an overview of site…

  2. Web Design Matters

    ERIC Educational Resources Information Center

    Mathews, Brian

    2009-01-01

    The web site is a library's most important feature. Patrons use the web site for numerous functions, such as renewing materials, placing holds, requesting information, and accessing databases. The homepage is the place they turn to look up the hours, branch locations, policies, and events. Whether users are at work, at home, in a building, or on…

  3. The Web's Unelected Government.

    ERIC Educational Resources Information Center

    Garfinkel, Simson L.

    1998-01-01

    The World Wide Web Consortium--an organization based at the Massachusetts Institute of Technology (MIT) that has 275 corporate members and holds closed meetings--is the closest thing the Web has to a central authority; however, almost nobody outside the telecommunications industry understands what the consortium is. Analyzes the role this body may…

  4. Making WEB Meaning.

    ERIC Educational Resources Information Center

    McKenzie, Jamie

    1996-01-01

    Poorly organized and dominated by amateurs, hucksters, and marketeers, the net requires efficient navigating devices. Students at Bellingham (Washington) Public Schools tackle information overload by contributing to virtual museums on school Web sites, using annotated Web curriculum lists, and conducting research in cooperative teams stressing…

  5. EPA Web Training Classes

    EPA Pesticide Factsheets

    Scheduled webinars can help you better manage EPA web content. Class topics include Drupal basics, creating different types of pages in the WebCMS such as document pages and forms, using Google Analytics, and best practices for metadata and accessibility.

  6. CERES Web Links

    Atmospheric Science Data Center

    2013-03-21

        Web Links to Relevant CERES Information Relevant information about ... questions about the CERES data can be found at the following web sites: CERES Home Page CERES TRMM Home Page ... Information page  on the Atmospheric Science Data Center site CERES "ARM" Validation Experiment (CAVE) Home Page  has ...

  7. Vibration Propagation in Spider Webs

    NASA Astrophysics Data System (ADS)

    Hatton, Ross; Otto, Andrew; Elias, Damian

    Due to their poor eyesight, spiders rely on web vibrations for situational awareness. Web-borne vibrations are used to determine the location of prey, predators, and potential mates. The influence of web geometry and composition on web vibrations is important for understanding spider's behavior and ecology. Past studies on web vibrations have experimentally measured the frequency response of web geometries by removing threads from existing webs. The full influence of web structure and tension distribution on vibration transmission; however, has not been addressed in prior work. We have constructed physical artificial webs and computer models to better understand the effect of web structure on vibration transmission. These models provide insight into the propagation of vibrations through the webs, the frequency response of the bare web, and the influence of the spider's mass and stiffness on the vibration transmission patterns. Funded by NSF-1504428.

  8. Funnel-web spider bite

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002844.htm Funnel-web spider bite To use the sharing features on ... the effects of a bite from the funnel-web spider. Male funnel-web spiders are more poisonous ...

  9. Macroscopic characterisations of Web accessibility

    NASA Astrophysics Data System (ADS)

    Lopes, Rui; Carriço, Luis

    2010-12-01

    The Web Science framework poses fundamental questions on the analysis of the Web, by focusing on how microscopic properties (e.g. at the level of a Web page or Web site) emerge into macroscopic properties and phenomena. One research topic on the analysis of the Web is Web accessibility evaluation, which centres on understanding how accessible a Web page is for people with disabilities. However, when framing Web accessibility evaluation on Web Science, we have found that existing research stays at the microscopic level. This article presents an experimental study on framing Web accessibility evaluation into Web Science's goals. This study resulted in novel accessibility properties of the Web not found at microscopic levels, as well as of Web accessibility evaluation processes themselves. We observed at large scale some of the empirical knowledge on how accessibility is perceived by designers and developers, such as the disparity of interpretations of accessibility evaluation tools warnings. We also found a direct relation between accessibility quality and Web page complexity. We provide a set of guidelines for designing Web pages, education on Web accessibility, as well as on the computational limits of large-scale Web accessibility evaluations.

  10. Chapter 59: Web Services

    NASA Astrophysics Data System (ADS)

    Graham, M. J.

    Web services are a cornerstone of the distributed computing infrastructure that the VO is built upon yet to the newcomer, they can appear to be a black art. This perception is not helped by the miasma of technobabble that pervades the subject and the seemingly impenetrable high priesthood of actual users. In truth, however, there is nothing conceptually difficult about web services (unsurprisingly any complexities will lie in the implementation details) nor indeed anything particularly new. A web service is a piece of software available over a network with a formal description of how it is called and what it returns that a computer can understand. Note that entities such as web servers, ftp servers and database servers do not generally qualify as they lack the standardized description of their inputs and outputs. There are prior technologies, such as RMI, CORBA, and DCOM, that have employed a similar approach but the success of web services lies predominantly in its use of standardized XML to provide a language-neutral way for representing data. In fact, the standardization goes further as web services are traditionally (or as traditionally as five years will allow) tied to a specific set of technologies (WSDL and SOAP conveyed using HTTP with an XML serialization). Alternative implementations are becoming increasingly common and we will cover some of these here. One important thing to remember in all of this, though, is that web services are meant for use by computers and not humans (unlike web pages) and this is why so much of it seems incomprehensible gobbledegook. In this chapter, we will start with an overview of the web services current in the VO and present a short guide on how to use and deploy a web service. We will then review the different approaches to web services, particularly REST and SOAP, and alternatives to XML as a data format. We will consider how web services can be formally described and discuss how advanced features such as security, state

  11. Chemistry WebBook

    National Institute of Standards and Technology Data Gateway

    SRD 69 NIST Chemistry WebBook (Web, free access)   The NIST Chemistry WebBook contains: Thermochemical data for over 7000 organic and small inorganic compounds; thermochemistry data for over 8000 reactions; IR spectra for over 16,000 compounds; mass spectra for over 33,000 compounds; UV/Vis spectra for over 1600 compounds; electronic and vibrational spectra for over 5000 compounds; constants of diatomic molecules(spectroscopic data) for over 600 compounds; ion energetics data for over 16,000 compounds; thermophysical property data for 74 fluids.

  12. Silicon web process development

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.

    1981-01-01

    The silicon web process takes advantage of natural crystallographic stabilizing forces to grow long, thin single crystal ribbons directly from liquid silicon. The ribbon, or web, is formed by the solidification of a liquid film supported by surface tension between two silicon filaments, called dendrites, which border the edges of the growing strip. The ribbon can be propagated indefinitely by replenishing the liquid silicon as it is transformed to crystal. The dendritic web process has several advantages for achieving low cost, high efficiency solar cells. These advantages are discussed.

  13. Web Content Management and One EPA Web Factsheet

    EPA Pesticide Factsheets

    One EPA Web is a multi-year project to improve EPA’s website to better meet the needs of our Web visitors. Content is developed and managed in the WebCMS which supports One EPA Web goals by standardizing how we create and publish content.

  14. Web Governance and Management

    EPA Pesticide Factsheets

    This Policy establishes that the U.S. Environmental Protection Agency will operate and maintain a public access Web site to assist in fulfilling the Agency’s mission - to protect the environment and public health.

  15. Learning: The Web.

    ERIC Educational Resources Information Center

    Smith, David A., Ed.; DeVries, David J., Ed.

    1999-01-01

    Explores what can be learned--in particular, what can be learned about science--from the Web sites of four well-known science journals: Discover, Scientific American, Nature, and Science. (Author/ASK)

  16. Silicon web process development

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Blais, P. D.; Davis, J. R., Jr.

    1977-01-01

    Thirty-five (35) furnace runs were carried out during this quarter, of which 25 produced a total of 120 web crystals. The two main thermal models for the dendritic growth process were completed and are being used to assist the design of the thermal geometry of the web growth apparatus. The first model, a finite element representation of the susceptor and crucible, was refined to give greater precision and resolution in the critical central region of the melt. The second thermal model, which describes the dissipation of the latent heat to generate thickness-velocity data, was completed. Dendritic web samples were fabricated into solar cells using a standard configuration and a standard process for a N(+) -P-P(+) configuration. The detailed engineering design was completed for a new dendritic web growth facility of greater width capability than previous facilities.

  17. Fun With Food Webs

    ERIC Educational Resources Information Center

    Smith, Karl D.

    1977-01-01

    Explains an upper elementary game of tag that illustrates energy flow in food webs using candy bars as food sources. A follow-up field trip to a river and five language arts projects are also suggested. (CS)

  18. A zooming Web browser

    SciTech Connect

    Bederson, B.B.; Hollan, J.D.; Stewart, J.; Rogers, D.; Vick, D.; Ring, L.; Grose, E.; Forsythe, C.

    1996-12-31

    We are developing a prototype zooming World-Wide Web browser within Pad++, a multiscale graphical environment. Instead of having a single page visible at a time, multiple pages and the links between them are depicted on a large zoomable information surface. Pages are scaled so that the page in focus is clearly readable with connected pages shown at smaller scales to provide context. We quantitatively compared performance with the Pad++ Web browser and Netscape in several different scenarios. We examined how quickly users could answer questions about a specific Web site designed for this test. Initially we found that subjects answered questions slightly slower with Pad++ than with Netscape. After analyzing the results of this study, we implemented several changes to the Pad++ Web browser, and repeated one Pad++ condition. After improvements were made to the Pad++ browser, subjects using Pad++ answered questions 23% faster than those using Netscape.

  19. Web surveys' hidden hazards.

    PubMed

    Morrel-Samuels, Palmer

    2003-07-01

    The same question posed on the Web and in print can yield very different answers, dramatically distorting survey results and misleading management. But, as psychologist Palmer Morrel-Samuels demonstrates, the problems are readily fixed.

  20. Web Operational Status Boards

    SciTech Connect

    Millard, W. David; Stoops, LaMar R.; Dorow, Kevin E.

    2004-04-16

    Web Operational Status Boards (WebOSB)is a web-based application designed to acquire, display, and update highly dynamic status information between multiple users and jurisdictions. WebOSB is able to disseminate real-time status information—support the timely sharing of information—with constant, dynamic updates via personal computers and the Internet between emergency operations centers (EOCs), incident command centers, and to users outside the EOC who need to know the information (hospitals, shelters, schools). The WebOSB application far exceeds outdated information-sharing methods used by emergency workers: whiteboards, Word and Excel documents, or even locality-specific Web sites. WebOSB’s capabilities include the following elements: - Secure access. Multiple users can access information on WebOSB from any personal computer with Internet access and a secure ID. Privileges are use to control access and distribution of status information and to identify users who are authorized to add or edit information. - Simultaneous update. WebOSB provides options for users to add, display, and update dynamic information simultaneously at all locations involved in the emergency management effort, A single status board can be updated from multiple locations enabling shelters and hospitals to post bed availability or list decontamination capability. - On-the-fly modification. Allowing the definition of an existing status board to be modified on-the-fly can be an asset during an emergency, where information requirements can change quickly. The status board designer feature allows an administrator to quickly define, modi,, add to, and implement new status boards in minutes without needing the help of Web designers and computer programmers. - Publisher/subscriber notification. As a subscriber, each user automatically receives notification of any new information relating to specific status boards. The publisher/subscriber feature automatically notified each user of any new

  1. Learning from WebQuests

    ERIC Educational Resources Information Center

    Gaskill, Martonia; McNulty, Anastasia; Brooks, David W.

    2006-01-01

    WebQuests are activities in which students use Web resources to learn about school topics. WebQuests are advocated as constructivist activities and ones generally well regarded by students. Two experiments were conducted in school settings to compare learning using WebQuests versus conventional instruction. Students and teachers both enjoyed…

  2. Optimal Experience of Web Activities.

    ERIC Educational Resources Information Center

    Chen, Hsiang; Wigand, R. T.; Nilan, M. S.

    1999-01-01

    Reports on Web users' optimal flow experiences to examine positive aspects of Web experiences that could be linked to theory applied to other media and then incorporated into Web design. Discusses the use of content-analytic procedures to analyze open-ended questionnaires that examined Web users' perceived flow experiences. (Author/LRW)

  3. Semantic Web for Manufacturing Web Services

    SciTech Connect

    Kulvatunyou, Boonserm; Ivezic, Nenad

    2002-06-01

    As markets become unexpectedly turbulent with a shortened product life cycle and a power shift towards buyers, the need for methods to rapidly and cost-effectively develop products, production facilities and supporting software is becoming urgent. The use of a virtual enterprise plays a vital role in surviving turbulent markets. However, its success requires reliable and large-scale interoperation among trading partners via a semantic web of trading partners' services whose properties, capabilities, and interfaces are encoded in an unambiguous as well as computer-understandable form. This paper demonstrates a promising approach to integration and interoperation between a design house and a manufacturer by developing semantic web services for business and engineering transactions. To this end, detailed activity and information flow diagrams are developed, in which the two trading partners exchange messages and documents. The properties and capabilities of the manufacturer sites are defined using DARPA Agent Markup Language (DAML) ontology definition language. The prototype development of semantic webs shows that enterprises can widely interoperate in an unambiguous and autonomous manner; hence, virtual enterprise is realizable at a low cost.

  4. ADASS XII Meeting Web Site

    NASA Astrophysics Data System (ADS)

    Liou, C.; Hulbert, S.

    We present the architecture, design, and implementation details of the ADASS XII web site. The web site was implemented in Zope, a high-performance application server, web server, and content management system rolled into one. Zope includes a robust, scalable object database, web services architecture, and powerful programming capabilities. The web site was built to conform to HTML, CSS, and accessibility standards as adopted by the W3C. This dynamic web site also taps into a back-end Sybase database while requiring a minimal amount of coding. We offer this site as a prototype web site suitable for reuse in supporting future ADASS meetings.

  5. Supporting Web Search with Visualization

    NASA Astrophysics Data System (ADS)

    Hoeber, Orland; Yang, Xue Dong

    One of the fundamental goals of Web-based support systems is to promote and support human activities on the Web. The focus of this Chapter is on the specific activities associated with Web search, with special emphasis given to the use of visualization to enhance the cognitive abilities of Web searchers. An overview of information retrieval basics, along with a focus on Web search and the behaviour of Web searchers is provided. Information visualization is introduced as a means for supporting users as they perform their primary Web search tasks. Given the challenge of visualizing the primarily textual information present in Web search, a taxonomy of the information that is available to support these tasks is given. The specific challenges of representing search information are discussed, and a survey of the current state-of-the-art in visual Web search is introduced. This Chapter concludes with our vision for the future of Web search.

  6. Building a better sticky trap: description of an easy-to-use trap and pole mount for quantifying the abundance of adult aquatic insects

    USGS Publications Warehouse

    Smith, Joshua T.; Kennedy, Theodore A.; Muehlbauer, Jeffrey D.

    2014-01-01

    Insect emergence is a fundamental process in freshwaters. It is a critical life-history stage for aquatic insects and provides an important prey resource for terrestrial and aquatic consumers. Sticky traps are increasingly being used to sample these insects. The most common design consists of an acetate sheet coated with a nondrying adhesive that is attached to a wire frame or cylinder. These traps must be prepared at the deployment site, a process that can be time consuming and difficult given the vagaries of field conditions. Our goals were to develop a sturdy, low-cost sticky trap that could be prepared in advance, rapidly deployed and recovered in the field, and used to estimate the flight direction of insects. We used 150-mm Petri dishes with lids. The dishes can be coated cleanly and consistently with Tangle-Trap® adhesive. Deploying traps is simple and requires only a pole set near the body of water being sampled. Four dishes can be attached to the pole using Velcro and aligned in 4 different directions to enable quantification of insect flight direction. After sampling, Petri dishes can be taped closed, packed in boxes, and stored indefinitely. Petri traps are comparable in price to standard acetate sheet traps at ∼US$0.50/directional deployment, but they require more space for storage than acetate sheet traps. However, a major benefit of Petri traps is that field deployment times are ⅓ those of acetate traps. Our study demonstrated that large Petri dishes are an ideal platform for sampling postemergent adult aquatic insects, particularly when the study design involves estimating flight direction and when rapid deployment and recovery of traps is critical.

  7. Geology and biology of the "Sticky Grounds", shelf-margin carbonate mounds, and mesophotic ecosystem in the eastern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Locker, Stanley D.; Reed, John K.; Farrington, Stephanie; Harter, Stacey; Hine, Albert C.; Dunn, Shane

    2016-08-01

    Shelf-margin carbonate mounds in water depths of 116-135 m in the eastern Gulf of Mexico along the central west Florida shelf were investigated using swath bathymetry, side-scan sonar, sub-bottom imaging, rock dredging, and submersible dives. These enigmatic structures, known to fisherman as the "Sticky Grounds", trend along slope, are 5-15 m in relief with base diameters of 5-30 m, and suggest widespread potential for mesophotic reef habitat along the west Florida outer continental shelf. Possible origins are sea-level lowstand coral patch reefs, oyster reefs, or perhaps more recent post-lowstand biohermal development. Rock dredging recovered bioeroded carbonate-rock facies comprised of bored and cemented bioclastics. Rock sample components included calcified worm tubes, pelagic sediment, and oysters normally restricted to brackish nearshore areas. Several reef sites were surveyed at the Sticky Grounds during a cruise in August 2010 with the R/V Seward Johnson using the Johnson-Sea-Link II submersible to ground truth the swath-sonar maps and to quantify and characterize the benthic habitats, benthic macrofauna, fish populations, and coral/sponge cover. This study characterizes for the first time this mesophotic reef ecosystem and associated fish populations, and analyzes the interrelationships of the fish assemblages, benthic habitats and invertebrate biota. These highly eroded rock mounds provide extensive hard-bottom habitat for reef invertebrate species as well as essential fish habitat for reef fish and commercially/recreationally important fish species. The extent and significance of associated living resources with these bottom types is particularly important in light of the 2010 Deepwater Horizon oil spill in the northeastern Gulf and the proximity of the Loop Current. Mapping the distribution of these mesophotic-depth ecosystems is important for quantifying essential fish habitat and describing benthic resources. These activities can improve ecosystem

  8. Borderless Geospatial Web (bolegweb)

    NASA Astrophysics Data System (ADS)

    Cetl, V.; Kliment, T.; Kliment, M.

    2016-06-01

    The effective access and use of geospatial information (GI) resources acquires a critical value of importance in modern knowledge based society. Standard web services defined by Open Geospatial Consortium (OGC) are frequently used within the implementations of spatial data infrastructures (SDIs) to facilitate discovery and use of geospatial data. This data is stored in databases located in a layer, called the invisible web, thus are ignored by search engines. SDI uses a catalogue (discovery) service for the web as a gateway to the GI world through the metadata defined by ISO standards, which are structurally diverse to OGC metadata. Therefore, a crosswalk needs to be implemented to bridge the OGC resources discovered on mainstream web with those documented by metadata in an SDI to enrich its information extent. A public global wide and user friendly portal of OGC resources available on the web ensures and enhances the use of GI within a multidisciplinary context and bridges the geospatial web from the end-user perspective, thus opens its borders to everybody. Project "Crosswalking the layers of geospatial information resources to enable a borderless geospatial web" with the acronym BOLEGWEB is ongoing as a postdoctoral research project at the Faculty of Geodesy, University of Zagreb in Croatia (http://bolegweb.geof.unizg.hr/). The research leading to the results of the project has received funding from the European Union Seventh Framework Programme (FP7 2007-2013) under Marie Curie FP7-PEOPLE-2011-COFUND. The project started in the November 2014 and is planned to be finished by the end of 2016. This paper provides an overview of the project, research questions and methodology, so far achieved results and future steps.

  9. Web Scraping for Astronomy

    NASA Astrophysics Data System (ADS)

    Derriere, S.; Boch, T.

    2012-09-01

    Astronomical web sites and portals are used daily by astronomers, and are increasingly interactive and customizable, mainly through the use of JavaScript. In addition, information often arises from the linking of remotely distributed data and contents. All these potential links can not always be defined in advance and stored in a web document for at least two reasons: they could potentially increase the size of the document source by a large fraction; and sometimes only the user (and not the document creator) knows where relevant links should be provided. Web scraping is the process of automatically collecting Web information. In this context, we started developing a method allowing retrieval of remote information, and display of this information (including links to remote websites) in the current document, triggered by a very simple action from the user: the selection of a portion of text in the web document. Our first prototype deals with astronomical object names. It is written in JavaScript, and can easily be implemented in a web document, or used as a bookmarklet. Whenever the user selects a portion of text in a web document, a request to the Sesame name resolver is made to test if this is a valid object identifier. On success, information retrieved in JSON allows to display a tooltip with additional information on this object such as its coordinates, links to various CDS services, image thumbnails, etc. We present the current status of this work, and discuss how it could be extended in the future to other applications.

  10. Factsheets Web Application

    SciTech Connect

    VIGIL,FRANK; REEDER,ROXANA G.

    2000-10-30

    The Factsheets web application was conceived out of the requirement to create, update, publish, and maintain a web site with dynamic research and development (R and D) content. Before creating the site, a requirements discovery process was done in order to accurately capture the purpose and functionality of the site. One of the high priority requirements for the site would be that no specialized training in web page authoring would be necessary. All functions of uploading, creation, and editing of factsheets needed to be accomplished by entering data directly into web form screens generated by the application. Another important requirement of the site was to allow for access to the factsheet web pages and data via the internal Sandia Restricted Network and Sandia Open Network based on the status of the input data. Important to the owners of the web site would be to allow the published factsheets to be accessible to all personnel within the department whether or not the sheets had completed the formal Review and Approval (R and A) process. Once the factsheets had gone through the formal review and approval process, they could then be published both internally and externally based on their individual publication status. An extended requirement and feature of the site would be to provide a keyword search capability to search through the factsheets. Also, since the site currently resides on both the internal and external networks, it would need to be registered with the Sandia search engines in order to allow access to the content of the site by the search engines. To date, all of the above requirements and features have been created and implemented in the Factsheet web application. These have been accomplished by the use of flat text databases, which are discussed in greater detail later in this paper.

  11. Understanding and Supporting Web Developers: Design and Evaluation of a Web Accessibility Information Resource (WebAIR).

    PubMed

    Swallow, David; Petrie, Helen; Power, Christopher

    2016-01-01

    This paper describes the design and evaluation of a Web Accessibility Information Resource (WebAIR) for supporting web developers to create and evaluate accessible websites. WebAIR was designed with web developers in mind, recognising their current working practices and acknowledging their existing understanding of web accessibility. We conducted an evaluation with 32 professional web developers in which they used either WebAIR or an existing accessibility information resource, the Web Content Accessibility Guidelines, to identify accessibility problems. The findings indicate that several design decisions made in relation to the language, organisation, and volume of WebAIR were effective in supporting web developers to undertake web accessibility evaluations.

  12. Source food webs as estimators of community web structure

    NASA Astrophysics Data System (ADS)

    Hawkins, Bradford A.; Martinez, Neo D.; Gilbert, Francis

    Taxonomically restricted "source webs" are commonly used to represent the community food webs of which they are part. This raises a methodological problem if source webs provide biased estimates of food web structure. We use four high quality, extensive food webs containing multiple source species to measure the sensitivity of food web metrics to the number of source species used to generate a web. The total number of species ( S), linkage density ( L/S), directed connectance ( L/S 2) and the fractions of basal ( B), intermediate ( I), and top ( T) species are all sensitive to the number of source species. Further, the pattern of variation for the latter fractions is inconsistent and web dependent, indicating that source webs are inappropriate for characterizing these properties. Linkage densities increase with the numbers of source species in all four cases, with webs based on single or few sources severely underestimating values obtained for the full webs. Connectance shows more constrained decreases with increasing numbers of sources, suggesting that multiple-source webs may provide reasonable estimates of connectance for community webs.

  13. Learning from WebQuests

    NASA Astrophysics Data System (ADS)

    Gaskill, Martonia; McNulty, Anastasia; Brooks, David W.

    2006-04-01

    WebQuests are activities in which students use Web resources to learn about school topics. WebQuests are advocated as constructivist activities and ones generally well regarded by students. Two experiments were conducted in school settings to compare learning using WebQuests versus conventional instruction. Students and teachers both enjoyed WebQuest instruction and spoke highly of it. In one experiment, however, conventional instruction led to significantly greater student learning. In the other, there were no significant differences in the learning outcomes between conventional versus WebQuest-based instruction.

  14. Development of Kevlar parachute webbings

    SciTech Connect

    Ericksen, R.H.

    1991-01-01

    This paper describes the development of Kevlar webbings for parachute applications. Evaluation of existing webbings and a study of the effects of filling yarn denier and pick count on tensile and joint strength provided data for fabric design. Measurements of warp crimp as a function of filling denier and pick count demonstrated the relationship between warp crimp and strength. One newly developed webbing had higher strength efficiency and another had higher joint efficiency than comparable existing webbings. Both new webbings had overall efficiencies over 5% higher than values for existing webbings. 10 refs., 4 figs., 2 tabs.

  15. WebTheme: Understanding Web Information through Visual Analytics

    SciTech Connect

    Whiting, Mark A.; Cramer, Nicholas O.

    2002-06-09

    WebTheme combines the power of software agent-based information retrieval with visual analytics to provide users with a new tool for understanding web information. WebTheme allows users to both quickly comprehend large collections of information from the Web and drill down into interesting portions of a collection. Software agents work for users to perform controlled harvesting of web material of interest. Visualization and analysis tools allow exploration of the resulting document space. Information spaces are organized and presented according to their topical context. Tools that display how documents were collected by the agents, where they were gathered, and how they are linked further enhance users? understanding of information and its context. WebTheme is a significant tool in the pursuit of the Semantic Web. In particular, it supports enhanced user insight into semantics of large, pre-structured or ad-hoc, web information collections.

  16. Semantic Sensor Web

    NASA Astrophysics Data System (ADS)

    Sheth, A.; Henson, C.; Thirunarayan, K.

    2008-12-01

    Sensors are distributed across the globe leading to an avalanche of data about our environment. It is possible today to utilize networks of sensors to detect and identify a multitude of observations, from simple phenomena to complex events and situations. The lack of integration and communication between these networks, however, often isolates important data streams and intensifies the existing problem of too much data and not enough knowledge. With a view to addressing this problem, the Semantic Sensor Web (SSW) [1] proposes that sensor data be annotated with semantic metadata that will both increase interoperability and provide contextual information essential for situational knowledge. Kno.e.sis Center's approach to SSW is an evolutionary one. It adds semantic annotations to the existing standard sensor languages of the Sensor Web Enablement (SWE) defined by OGC. These annotations enhance primarily syntactic XML-based descriptions in OGC's SWE languages with microformats, and W3C's Semantic Web languages- RDF and OWL. In association with semantic annotation and semantic web capabilities including ontologies and rules, SSW supports interoperability, analysis and reasoning over heterogeneous multi-modal sensor data. In this presentation, we will also demonstrate a mashup with support for complex spatio-temporal-thematic queries [2] and semantic analysis that utilize semantic annotations, multiple ontologies and rules. It uses existing services (e.g., GoogleMap) and semantics enhanced SWE's Sensor Observation Service (SOS) over weather and road condition data from various sensors that are part of Ohio's transportation network. Our upcoming plans are to demonstrate end to end (heterogeneous sensor to application) semantics support and study scalability of SSW involving thousands of sensors to about a billion triples. Keywords: Semantic Sensor Web, Spatiotemporal thematic queries, Semantic Web Enablement, Sensor Observation Service [1] Amit Sheth, Cory Henson, Satya

  17. Dynamic Web Pages: Performance Impact on Web Servers.

    ERIC Educational Resources Information Center

    Kothari, Bhupesh; Claypool, Mark

    2001-01-01

    Discussion of Web servers and requests for dynamic pages focuses on experimentally measuring and analyzing the performance of the three dynamic Web page generation technologies: CGI, FastCGI, and Servlets. Develops a multivariate linear regression model and predicts Web server performance under some typical dynamic requests. (Author/LRW)

  18. Designing Effective Web Forms for Older Web Users

    ERIC Educational Resources Information Center

    Li, Hui; Rau, Pei-Luen Patrick; Fujimura, Kaori; Gao, Qin; Wang, Lin

    2012-01-01

    This research aims to provide insight for web form design for older users. The effects of task complexity and information structure of web forms on older users' performance were examined. Forty-eight older participants with abundant computer and web experience were recruited. The results showed significant differences in task time and error rate…

  19. APPRIS WebServer and WebServices.

    PubMed

    Rodriguez, Jose Manuel; Carro, Angel; Valencia, Alfonso; Tress, Michael L

    2015-07-01

    This paper introduces the APPRIS WebServer (http://appris.bioinfo.cnio.es) and WebServices (http://apprisws.bioinfo.cnio.es). Both the web servers and the web services are based around the APPRIS Database, a database that presently houses annotations of splice isoforms for five different vertebrate genomes. The APPRIS WebServer and WebServices provide access to the computational methods implemented in the APPRIS Database, while the APPRIS WebServices also allows retrieval of the annotations. The APPRIS WebServer and WebServices annotate splice isoforms with protein structural and functional features, and with data from cross-species alignments. In addition they can use the annotations of structure, function and conservation to select a single reference isoform for each protein-coding gene (the principal protein isoform). APPRIS principal isoforms have been shown to agree overwhelmingly with the main protein isoform detected in proteomics experiments. The APPRIS WebServer allows for the annotation of splice isoforms for individual genes, and provides a range of visual representations and tools to allow researchers to identify the likely effect of splicing events. The APPRIS WebServices permit users to generate annotations automatically in high throughput mode and to interrogate the annotations in the APPRIS Database. The APPRIS WebServices have been implemented using REST architecture to be flexible, modular and automatic.

  20. Web-dendritic ribbon growth

    NASA Technical Reports Server (NTRS)

    Hilborn, R. B., Jr.; Faust, J. W., Jr.

    1976-01-01

    A web furnace was constructed for pulling dendritic-web samples. The effect of changes in the furnace thermal geometry on the growth of dendritic-web was studied. Several attempts were made to grow primitive dendrites for use as the dendritic seed crystals for web growth and to determine the optimum twin spacing in the dendritic seed crystal for web growth. Mathematical models and computer programs were used to determine the thermal geometries in the susceptor, crucible melt, meniscus, and web. Several geometries were determined for particular furnace geometries and growth conditions. The information obtained was used in conjunction with results from the experimental growth investigations in order to achieve proper conditions for sustained pulling of two dendrite web ribbons. In addition, the facilities for obtaining the following data were constructed: twin spacing, dislocation density, web geometry, resistivity, majority charge carrier type, and minority carrier lifetime.

  1. Code AI Personal Web Pages

    NASA Technical Reports Server (NTRS)

    Garcia, Joseph A.; Smith, Charles A. (Technical Monitor)

    1998-01-01

    The document consists of a publicly available web site (george.arc.nasa.gov) for Joseph A. Garcia's personal web pages in the AI division. Only general information will be posted and no technical material. All the information is unclassified.

  2. Yahoo! Cataloging the Web.

    ERIC Educational Resources Information Center

    Callery, Anne

    The Internet has the potential to be the ultimate information resource, but it needs to be organized in order to be useful. This paper discusses how the subject guide, "Yahoo!" is different from most web search engines, and how best to search for information on Yahoo! The strength in Yahoo! lies in the subject hierarchy. Advantages to…

  3. Caught on the Web

    ERIC Educational Resources Information Center

    Isakson, Carol

    2005-01-01

    In this article, the author presents several Web sites supporting electronic presentation skills. The sites featured here will help fine-tune one's skills in modeling effective presentations and provide suggestions for managing student presentations meeting National Educational Technology Standards (NETS). Most use PowerPoint, the current industry…

  4. Experiments in Web Storytelling

    ERIC Educational Resources Information Center

    Levine, Alan

    2011-01-01

    Recognized as one of our oldest yet still vital forms of communication, storytelling offers new opportunity when it takes place on the web. Even our every day activities of writing email, creating presentations, or participating in social media can become more dynamic when considered stories. A digital storyteller from outside the museum field…

  5. Spider Webs and Silks.

    ERIC Educational Resources Information Center

    Vollrath, Fritz

    1992-01-01

    Compares the attributes of the silk from spiders with those of the commercially harvested silk from silkworms. Discusses the evolution, design, and effectiveness of spider webs; the functional mechanics of the varieties of silk that can be produced by the same spider; and the composite, as well as molecular, structure of spider silk thread. (JJK)

  6. WebWatch.

    ERIC Educational Resources Information Center

    Nesbeitt, Sarah

    1997-01-01

    Numerous Web-based phone and address directories provide advantages over the white and yellow pages. Although many share a common database, each has features that set it apart: maps, suggested driving directions, and phone dialing. This article examines eight (Bigfoot, BigBook, BigYellow, Switchboard, Infospace, Contractjobs, InterNIC)…

  7. Caught on the Web

    ERIC Educational Resources Information Center

    Isakson, Carol

    2006-01-01

    In this article, the author presents Web sites about teen use of online social networks and age-appropriate resources. These resources can be used for teaching students ways in which to use these networks safely and ethically. Among other things, "Social Network Service" entry in Wikipedia, offers a description and a "List of Social Networking…

  8. Spinning a Web Search.

    ERIC Educational Resources Information Center

    Lager, Mark A.

    This paper focuses on techniques for retrieval used in information sciences and in World Wide Web search engines. The purpose of reference service and information science is to provide useful information in response to a query. The two metrics of recall and precision serve to express information retrieval performance. There are two major…

  9. Spelling and the Web

    ERIC Educational Resources Information Center

    Varnhagen, Connie K.; McFall, G. Peggy; Figueredo, Lauren; Takach, Bonnie Sadler; Daniels, Jason; Cuthbertson, Heather

    2008-01-01

    Correct spelling is increasingly important in our technological world. We examined children's and adults' Web search behavior for easy and more difficult to spell target keywords. Grade 4 children and university students searched for the life cycle of the lemming (easy to spell target keyword) or the ptarmigan (difficult to spell target keyword).…

  10. WebWatch.

    ERIC Educational Resources Information Center

    Aycock, Anthony

    2002-01-01

    Describes 13 Web sites that relate to archives, including how to operate them, how to find them, and the ethical and professional questions archivists confront. Special focus is given to the Society of American Archivists, the National Archives and Records Administration, and Using Archives: A Practical Guide for Researchers. (LRW)

  11. Silicon web process development

    NASA Technical Reports Server (NTRS)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hill, F. E.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.

    1980-01-01

    A barrier crucible design which consistently maintains melt stability over long periods of time was successfully tested and used in long growth runs. The pellet feeder for melt replenishment was operated continuously for growth runs of up to 17 hours. The liquid level sensor comprising a laser/sensor system was operated, performed well, and meets the requirements for maintaining liquid level height during growth and melt replenishment. An automated feedback loop connecting the feed mechanism and the liquid level sensing system was designed and constructed and operated successfully for 3.5 hours demonstrating the feasibility of semi-automated dendritic web growth. The sensitivity of the cost of sheet, to variations in capital equipment cost and recycling dendrites was calculated and it was shown that these factors have relatively little impact on sheet cost. Dendrites from web which had gone all the way through the solar cell fabrication process, when melted and grown into web, produce crystals which show no degradation in cell efficiency. Material quality remains high and cells made from web grown at the start, during, and the end of a run from a replenished melt show comparable efficiencies.

  12. Lower oesophageal web

    PubMed Central

    Björk, Viking Olov; Charonis, Constantin G.

    1967-01-01

    A patient with a `congenital' oesophageal web was suffering from dysphagia and was treated surgically. A review is made of a few similar, well-documented cases. An effort is made to compare the clinical and pathological characteristics of the lesion and to discuss its pathogenesis. Images PMID:6033383

  13. WebWatch.

    ERIC Educational Resources Information Center

    Newcombe, Pat

    2002-01-01

    Reviews ten Web sites that are designed to answer basic legal questions for the layperson. They provide resources on a broad range of legal topics, such as divorce, real estate, and criminal justice, as well as legal forms and information on finding a lawyer. (LRW)

  14. Forensic web watch 4.

    PubMed

    Lumb, P; Rutty, G N

    2000-06-01

    Finding dedicated sites on the World Wide Web (WWW) touching upon issues related to the autopsy which could be of use to forensic practitioners is, as with other areas of forensic medicine and science, a time-consuming task. Unfortunately, one has to wade through lists related to 'Alien autopsy' sites and even 'Furby autopsy' sites that are generated by the most commonly used web search engines, which have been featured in earlier web reviews. Numerous sites containing large archives of autopsy photographs are available on the web. However, many of these sites represent the darker side of the WWW as they are often presented purely for titillation. Unfortunately, one can equate these sites to the modern-day version of the Victorian 'freak show'--Typically, these sites ask for your Visa card number to view their contents, and several have links to pornography sites; one even links to a Satanist site. Luckily a few of these sites do now require age confirmation codes. As many of these sites show autopsy photographs from real cases one has to ask how these were obtained and who is placing them on the WWW. This review does not list any of these sites for obvious reasons, but it does draw the reader's attention to sites touching upon issues related to autopsies which forensic practitioners may wish to visit or use.

  15. Web Development Simplified

    ERIC Educational Resources Information Center

    Becker, Bernd W.

    2010-01-01

    The author has discussed the Multimedia Educational Resource for Teaching and Online Learning site, MERLOT, in a recent Electronic Roundup column. In this article, he discusses an entirely new Web page development tool that MERLOT has added for its members. The new tool is called the MERLOT Content Builder and is directly integrated into the…

  16. Semantic Web Development

    DTIC Science & Technology

    2006-09-01

    many documents are not expressible in logica at all, and many in logic but not in N3. However, we are building a system for which a prime goal is the...demonstrate that conventional logica programming tools are efficent and straightforwradly adapted to semantic web work. • Jena RDF toolkit now accepts N3 as

  17. A Web Policy Primer.

    ERIC Educational Resources Information Center

    Levine, Elliott

    2001-01-01

    Sound technology policies can spell the difference between an effective website and an online nightmare. An effective web development policy addresses six key areas: roles and responsibilities, content/educational value, privacy and safety, adherence to copyright laws, technical standards, and use of commercial sites and services. (MLH)

  18. Elementary Classroom Web Sites

    ERIC Educational Resources Information Center

    Baker, Elizabeth A.

    2007-01-01

    The purpose of this study was to understand how elementary classroom Web sites support children's literacy. From a sociocultural perspective of literacy and a transformative stance toward the integration of literacy and technology, and building on explorations of new literacies, I discuss opportunities provided by the Internet that can support…

  19. Spider Web Pattern

    NASA Technical Reports Server (NTRS)

    2006-01-01

    A delicate pattern, like that of a spider web, appears on top of the Mars residual polar cap, after the seasonal carbon-dioxide ice slab has disappeared. Next spring, these will likely mark the sites of vents when the carbon-dioxide ice cap returns. This Mars Global Surveyor, Mars Orbiter Camera image is about 3-kilometers wide (2-miles).

  20. Geology and biology of the "Sticky Grounds," shelf-margin carbonate mounds, and mesophotic ecosystem in the eastern Gulf of Mexico

    USGS Publications Warehouse

    Locker, Stanley D.; Reed, John K.; Farrington, Stephanie; Harter, Stacey; Hine, Albert C.; Dunn, Shane

    2016-01-01

    Shelf-margin carbonate mounds in water depths of 116–135 m in the eastern Gulf of Mexico along the central west Florida shelf were investigated using swath bathymetry, side-scan sonar, sub-bottom imaging, rock dredging, and submersible dives. These enigmatic structures, known to fisherman as the “Sticky Grounds”, trend along slope, are 5–15 m in relief with base diameters of 5–30 m, and suggest widespread potential for mesophotic reef habitat along the west Florida outer continental shelf. Possible origins are sea-level lowstand coral patch reefs, oyster reefs, or perhaps more recent post-lowstand biohermal development. Rock dredging recovered bioeroded carbonate-rock facies comprised of bored and cemented bioclastics. Rock sample components included calcified worm tubes, pelagic sediment, and oysters normally restricted to brackish nearshore areas. Several reef sites were surveyed at the Sticky Grounds during a cruise in August 2010 with the R/V Seward Johnson using the Johnson-Sea-Link II submersible to ground truth the swath-sonar maps and to quantify and characterize the benthic habitats, benthic macrofauna, fish populations, and coral/sponge cover. This study characterizes for the first time this mesophotic reef ecosystem and associated fish populations, and analyzes the interrelationships of the fish assemblages, benthic habitats and invertebrate biota. These highly eroded rock mounds provide extensive hard-bottom habitat for reef invertebrate species as well as essential fish habitat for reef fish and commercially/recreationally important fish species. The extent and significance of associated living resources with these bottom types is particularly important in light of the 2010 Deepwater Horizon oil spill in the northeastern Gulf and the proximity of the Loop Current. Mapping the distribution of these mesophotic-depth ecosystems is important for quantifying essential fish habitat and describing benthic resources. These activities can improve

  1. Information Diversity in Web Search

    ERIC Educational Resources Information Center

    Liu, Jiahui

    2009-01-01

    The web is a rich and diverse information source with incredible amounts of information about all kinds of subjects in various forms. This information source affords great opportunity to build systems that support users in their work and everyday lives. To help users explore information on the web, web search systems should find information that…

  2. The Web Resource Collaboration Center

    ERIC Educational Resources Information Center

    Dunlap, Joanna C.

    2004-01-01

    The Web Resource Collaboration Center (WRCC) is a web-based tool developed to help software engineers build their own web-based learning and performance support systems. Designed using various online communication and collaboration technologies, the WRCC enables people to: (1) build a learning and professional development resource that provides…

  3. Sensor system for web inspection

    DOEpatents

    Sleefe, Gerard E.; Rudnick, Thomas J.; Novak, James L.

    2002-01-01

    A system for electrically measuring variations over a flexible web has a capacitive sensor including spaced electrically conductive, transmit and receive electrodes mounted on a flexible substrate. The sensor is held against a flexible web with sufficient force to deflect the path of the web, which moves relative to the sensor.

  4. The Semantic Web in Education

    ERIC Educational Resources Information Center

    Ohler, Jason

    2008-01-01

    The semantic web or Web 3.0 makes information more meaningful to people by making it more understandable to machines. In this article, the author examines the implications of Web 3.0 for education. The author considers three areas of impact: knowledge construction, personal learning network maintenance, and personal educational administration.…

  5. Designing a WebQuest

    ERIC Educational Resources Information Center

    Salsovic, Annette R.

    2009-01-01

    A WebQuest is an inquiry-based lesson plan that uses the Internet. This article explains what a WebQuest is, shows how to create one, and provides an example. When engaged in a WebQuest, students use technology to experience cooperative learning and discovery learning while honing their research, writing, and presentation skills. It has been found…

  6. The Art of Web Design

    ERIC Educational Resources Information Center

    Longe, Heather

    2008-01-01

    The essential components to building a successful Web site are many times overlooked. There is a misconception that if an individual knows HTML or is a Web developer, an effective Web site can easily be created. In reality, a variety of other factors are needed before technical skills ever come into play. When instructing students in the art of…

  7. Web Browser Trends and Technologies.

    ERIC Educational Resources Information Center

    Goodwin-Jones, Bob

    2000-01-01

    Discusses Web browsers and how their capabilities have been expanded, support for Web browsing on different devices (cell phones, palmtop computers, TV sets), and browser support for the next-generation Web authoring language, XML ("extensible markup language"). (Author/VWL)

  8. Publicity through Better Web Site Design.

    ERIC Educational Resources Information Center

    Guenther, Kim

    1999-01-01

    Describes how to design Web sites that will reach the most people possible. Discusses publicity; Web search engine sites; adopting Web development standards; using metatags to effectively index a site; Web site addresses and naming conventions; writing for the Web; mass submissions; subject area knowledge; making Web rings; and additional ideas to…

  9. Web Services Integration on the Fly

    DTIC Science & Technology

    2008-12-01

    22 K. WEB SERVICES CHOREOGRAPHY DESCRIPTION LANGUAGE (WS-CDL...Intelligent Framework WSBPEL Web Services Business Process Execution Language WS-CDL Web Services Choreography Description Language WSDL Web...Language (WSBPEL) is a related technology addressing service orchestration. Web Services Choreography and Web Services Security are important areas

  10. Web Usage, Advertising, and Shopping: Relationship Patterns.

    ERIC Educational Resources Information Center

    Korgaonkar, Pradeep; Wolin, Lori D.

    2002-01-01

    Discusses Web sales and explores the differences between heavy, medium, and light Web users in terms of their beliefs about Web advertising, attitudes toward Web advertising, purchasing patterns, and demographics. Suggests marketers need to target Web advertising to particular Web users. (Author/LRW)

  11. Structure determination of a tetrahydro-beta-carboline of arthropod origin: a novel alkaloid-toxin subclass from the web of spider Nephila clavipes.

    PubMed

    Marques, Maurício Ribeiro; Mendes, Maria Anita; Tormena, Cláudio Francisco; Souza, Bibiana M; Cesar, Lílian Mari Marcondes; Rittner, Roberto; Palma, Mario S

    2005-04-01

    The orb-web spiders are polyphagous animals in which the web plays a very important role in the capture of preys; oily droplets usually cover the capture-web of the spider Nephila clavipes and seem to be of great importance for prey capture. The knowledge of the chemical composition of these droplets is necessary to understand the function of this adhesive material in web mechanics and prey capture. A novel subclass of spider toxins, tetrahydro-beta-carboline, was identified among the weaponry of compounds present inside of oily droplets. This type of alkaloid is not common among the natural compounds of spider toxins. Apparently, when the prey arthropods get caught by the spider web, their bodies are covered with many adhesive oily droplets, which disrupt delivering the tetrahydro-beta-carboline to the direct contact with the prey integument. Toxicity assays demonstrated a potent lethal effect of the alkaloid toxin to the spider preys; topical applications of the tetrahydro-beta-carboline at first caused clear signs of neurotoxicity, followed by the death of preys. The structure of the major component, a tetrahydro-beta-carboline, among the alkaloid toxins was elucidated by means of UV spectrophotometry, ESI mass spectrometry, 1H-NMR spectroscopy, and high-resolution mass spectrometry. The structure of the natural toxin was determined as 1-(2-guanidinoethyl)-1,2,3,4-tetrahydro-6-hydroxymethyl)-beta-carboline; the investigation of the pharmacological properties and neurotoxic actions of this compound may be used in the future as reference for the development of new drugs to be applied at level of pest control in agriculture.

  12. WEBtop (Operating Systems on Web)

    NASA Astrophysics Data System (ADS)

    Sharma, M. K.; Kumar, Rajeev

    2011-12-01

    WebOS (Web based operating system) is a new form of Operating Systems. You can use your desktop as a virtual desktop on the web, accessible via a browser, with multiple integrated built-in applications that allow the user to easily manage and organize her data from any location. Desktop on web can be named as WEBtop. This paper starts with a introduction of WebOS and its benefits. For this paper, We have reviewed some most interesting WebOS available nowadays and tried to provide a detailed description of their features. We have identified some parameters as comparison criteria among them. A technical review is given with research design and future goals to design better web based operating systems is a part of this study. Findings of the study conclude this paper.

  13. Non-sticky translocation of bio-molecules through Tween 20-coated solid-state nanopores in a wide pH range

    NASA Astrophysics Data System (ADS)

    Li, Xiaoqing; Hu, Rui; Li, Ji; Tong, Xin; Diao, J. J.; Yu, Dapeng; Zhao, Qing

    2016-10-01

    Nanopore-based sensing technology is considered high-throughput and low-cost for single molecule detection, but solid-state nanopores have suffered from pore clogging issues. A simple Tween 20 coating method is applied to ensure long-term (several hours) non-sticky translocation of various types of bio-molecules through SiN nanopores in a wide pH range (4.0-13.0). We also emphasize the importance of choosing appropriate concentration of Tween 20 coating buffer for desired effect. By coating nanopores with a Tween 20 layer, we are able to differentiate between single-stranded DNA and double-stranded DNA, to identify drift-dominated domain for single-stranded DNA, to estimate BSA volume and to observe the shape of individual nucleosome translocation event without non-specific adsorption. The wide pH endurance from 4.0 to 13.0 and the broad types of detection analytes including nucleic acids, proteins, and biological complexes highlight the great application potential of Tween 20-coated solid-state nanopores.

  14. Monitoring/characterization of stickies contaminants coming from a papermaking plant--Toward an innovative exploitation of the screen rejects to levulinic acid.

    PubMed

    Licursi, Domenico; Antonetti, Claudia; Martinelli, Marco; Ribechini, Erika; Zanaboni, Marco; Raspolli Galletti, Anna Maria

    2016-03-01

    Recycled paper needs a lot of mechanical/chemical treatments for its re-use in the papermaking process. Some of these ones produce considerable rejected waste fractions, such as "screen rejects", which include both cellulose fibers and non-fibrous organic contaminants, or "stickies", these last representing a shortcoming both for the papermaking process and for the quality of the final product. Instead, the accepted fractions coming from these unit operations become progressively poorer in contaminants and richer in cellulose. Here, input and output streams coming from mechanical screening systems of a papermaking plant using recycled paper for cardboard production were sampled and analyzed directly and after solvent extraction, thus confirming the abundant presence of styrene-butadiene rubber (SBR) and ethylene vinyl acetate (EVA) copolymers in the output rejected stream and cellulose in the output accepted one. Despite some significant drawbacks, the "screen reject" fraction could be traditionally used as fuel for energy recovery within the paper mill, in agreement with the integrated recycled paper mill approach. The waste, which still contains a cellulose fraction, can be also exploited by means of the hydrothermal route to give levulinic acid, a platform chemical of very high value added.

  15. A novel class of sticky peel and light green mutations causes cuticle deficiency in leaves and fruits of tomato (Solanum lycopersicum).

    PubMed

    Kimbara, Junji; Yoshida, Miho; Ito, Hirotaka; Hosoi, Katsutoshi; Kusano, Miyako; Kobayashi, Makoto; Ariizumi, Tohru; Asamizu, Erika; Ezura, Hiroshi

    2012-11-01

    The plant cuticle consists of aliphatic wax and cutin, and covers all the aerial tissues, conferring resistance to both biotic and abiotic stresses. In this study, we performed phenotypic characterizations of tomato mutants having both sticky peel (pe) and light green (lg) mutations. Our genetic analysis showed that these two mutations are tightly linked and behave like a monogenic recessive mutation. The double mutant (pe lg) produced glossy soft fruits with light green leaves, most likely due to defects in cuticle formation. Cytological analysis revealed that the thickness of the fruit cuticle layer was dramatically reduced in the pe lg mutant. The epidermal cells of the leaves were also deformed in the pe lg mutant, suggesting that leaf cuticle formation was also disrupted in the mutant. Consistent with this, transmission electron microscopic analysis showed that the electron density of the cuticle layer of the adaxial surface of the leaf was reduced in the pe lg mutant compared to WT, suggesting that there are changes in cuticle structure and/or composition in the pe lg mutant. Both physiological analysis to measure the rate of transpiration, and staining of the fruits and leaves with toluidine blue, revealed that water permeability was enhanced in the pe lg mutant, consistent with the reduced thickness of its cuticle layer. Taken together the preliminary analyses of the cuticle components, the PE LG is most likely involved in proper cuticle formation.

  16. Web Resources for Pharmacogenomics

    PubMed Central

    Zhang, Guoqing; Zhang, Yunsheng; Ling, Yunchao; Jia, Jia

    2015-01-01

    Pharmacogenomics is the study of the impact of genetic variations or genotypes of individuals on their drug response or drug metabolism. Compared to traditional genomics research, pharmacogenomic research is more closely related to clinical practice. Pharmacogenomic discoveries may effectively assist clinicians and healthcare providers in determining the right drugs and proper dose for each patient, which can help avoid side effects or adverse reactions, and improve the drug therapy. Currently, pharmacogenomic approaches have proven their utility when it comes to the use of cardiovascular drugs, antineoplastic drugs, aromatase inhibitors, and agents used for infectious diseases. The rapid innovation in sequencing technology and genome-wide association studies has led to the development of numerous data resources and dramatically changed the landscape of pharmacogenomic research. Here we describe some of these web resources along with their names, web links, main contents, and our ratings. PMID:25703229

  17. Silicon dendritic web material

    NASA Technical Reports Server (NTRS)

    Meier, D. L.; Campbell, R. B.; Sienkiewicz, L. J.; Rai-Choudhury, P.

    1982-01-01

    The development of a low cost and reliable contact system for solar cells and the fabrication of several solar cell modules using ultrasonic bonding for the interconnection of cells and ethylene vinyl acetate as the potting material for module encapsulation are examined. The cells in the modules were made from dendritic web silicon. To reduce cost, the electroplated layer of silver was replaced with an electroplated layer of copper. The modules that were fabricated used the evaporated Ti, Pd, Ag and electroplated Cu (TiPdAg/Cu) system. Adherence of Ni to Si is improved if a nickel silicide can be formed by heat treatment. The effectiveness of Ni as a diffusion barrier to Cu and the ease with which nickel silicide is formed is discussed. The fabrication of three modules using dendritic web silicon and employing ultrasonic bonding for interconnecting calls and ethylene vinyl acetate as the potting material is examined.

  18. WebLogo

    SciTech Connect

    Crooks, Gavin E.

    2003-01-08

    WebLogo is a web based application designed to make the generation of sequence logos as easy and painless as possible. Sequesnce logos are a graphical representation of an amino acid or nucleic acid multiple sequence alignment developed by Tom Schneider and Mike Stephens. Each logo consists of stacks of symbols, one stack for each position in the sequence. The overall height of the stack indicates the sequence conservation at that position, while the height of symbols within the stack indicates the relative frequency of each amino or nucleic acid at that position. In general, a sequence logo provides a richer and more precise description of, for example, a binding site, than would a consensus sequence.

  19. Vote using the Web

    NASA Astrophysics Data System (ADS)

    Schmoltner, Anne-Marie

    In an effort to increase the strength of AGU by increasing participation in voting, you will be able to cast your ballot for AGU officers on the Web this year. The Tellers Committee is working with an experienced firm, election.com, to develop procedures for conducting AGU's first electronic election in November and December 2001. You will be able to cast your votes for the officers of your choice, among the 62 candidates, by going to a secure Web site, or by requesting a paper ballot.An amendment to the District of Columbia law now permits non-profit organizations incorporated in Washington, D.C. to conduct elections using electronic voting. AGU was instrumental in getting the amendment adopted by the Council of the District of Columbia in spring 2001.

  20. Promoting Teachers' Positive Attitude towards Web Use: A Study in Web Site Development

    ERIC Educational Resources Information Center

    Akpinar, Yavuz; Bayramoglu, Yusuf

    2008-01-01

    The purpose of the study was to examine effects of a compact training for developing web sites on teachers' web attitude, as composed of: web self efficacy, perceived web enjoyment, perceived web usefulness and behavioral intention to use the web. To measure the related constructs, the Web Attitude Scale was adapted into Turkish and tested with a…

  1. Google's Web Page Ranking Applied to Different Topological Web Graph Structures.

    ERIC Educational Resources Information Center

    Meghabghab, George

    2001-01-01

    This research, part of the ongoing study to better understand Web page ranking on the Web, looks at a Web page as a graph structure or Web graph, and classifies different Web graphs in the new coordinate space (out-degree, in-degree). Google's Web ranking algorithm (Brin & Page, 1998) on ranking Web pages is applied in this new coordinate…

  2. Forensic web watch.

    PubMed

    Rutty, G N

    1999-09-01

    Since the development of the Internet (Net) by the Americans in the 1970s as a potential means of communication following a future world war, it has evolved over the decades into the graphical format of the world-wide web (WWW, Web) that we know today. Anyone accessing the Net, be it from home or work, has access to information and resources on almost anything but with this comes the time-consuming and potentially expensive task of identifying those sites of use in one's professional work from those of purely interest or fun. These reviews will try and direct those working within forensic practice in all professions towards sites considered by the author to be practical resources. They are, by their very nature, a personal opinion and the author recognizes that the review of a site by one person may differ considerably from that of another user or the site designer. The articles will assume a basic knowledge of how to access and use the WWW using either Netscape or Microsoft Explorer. They will address groups of sites related to common areas of practice listing key web addresses to allow those interested to access sites reviewed. Because of the time between writing and publishing some sites may no longer be valid

  3. An Efficient Web Page Ranking for Semantic Web

    NASA Astrophysics Data System (ADS)

    Chahal, P.; Singh, M.; Kumar, S.

    2014-01-01

    With the enormous amount of information presented on the web, the retrieval of relevant information has become a serious problem and is also the topic of research for last few years. The most common tools to retrieve information from web are search engines like Google. The Search engines are usually based on keyword searching and indexing of web pages. This approach is not very efficient as the result-set of web pages obtained include large irrelevant pages. Sometimes even the entire result-set may contain lot of irrelevant pages for the user. The next generation of search engines must address this problem. Recently, many semantic web search engines have been developed like Ontolook, Swoogle, which help in searching meaningful documents presented on semantic web. In this process the ranking of the retrieved web pages is very crucial. Some attempts have been made in ranking of semantic web pages but still the ranking of these semantic web documents is neither satisfactory and nor up to the user's expectations. In this paper we have proposed a semantic web based document ranking scheme that relies not only on the keywords but also on the conceptual instances present between the keywords. As a result only the relevant page will be on the top of the result-set of searched web pages. We explore all relevant relations between the keywords exploring the user's intention and then calculate the fraction of these relations on each web page to determine their relevance. We have found that this ranking technique gives better results than those by the prevailing methods.

  4. WebVR: an interactive web browser for virtual environments

    NASA Astrophysics Data System (ADS)

    Barsoum, Emad; Kuester, Falko

    2005-03-01

    The pervasive nature of web-based content has lead to the development of applications and user interfaces that port between a broad range of operating systems and databases, while providing intuitive access to static and time-varying information. However, the integration of this vast resource into virtual environments has remained elusive. In this paper we present an implementation of a 3D Web Browser (WebVR) that enables the user to search the internet for arbitrary information and to seamlessly augment this information into virtual environments. WebVR provides access to the standard data input and query mechanisms offered by conventional web browsers, with the difference that it generates active texture-skins of the web contents that can be mapped onto arbitrary surfaces within the environment. Once mapped, the corresponding texture functions as a fully integrated web-browser that will respond to traditional events such as the selection of links or text input. As a result, any surface within the environment can be turned into a web-enabled resource that provides access to user-definable data. In order to leverage from the continuous advancement of browser technology and to support both static as well as streamed content, WebVR uses ActiveX controls to extract the desired texture skin from industry strength browsers, providing a unique mechanism for data fusion and extensibility.

  5. Use of Semantic Web technologies on the BBC Web Sites

    NASA Astrophysics Data System (ADS)

    Raimond, Yves; Scott, Tom; Oliver, Silver; Sinclair, Patrick; Smethurst, Michael

    The BBC publishes large amounts of content online, as text, audio and video. As the amount of content grows, we need to make it easy for users to locate items of interest and to draw coherent journeys across them. In this chapter, we describe our use of Semantic Web technologies for achieving this goal. We focus in particular on three BBC Web sites: BBC Programmes, BBC Music and BBC Wildlife Finder, and how those Web sites effectively use the wider Web as their Content Management System.

  6. SVG-Based Web Publishing

    NASA Astrophysics Data System (ADS)

    Gao, Jerry Z.; Zhu, Eugene; Shim, Simon

    2003-01-01

    With the increasing applications of the Web in e-commerce, advertising, and publication, new technologies are needed to improve Web graphics technology due to the current limitation of technology. The SVG (Scalable Vector Graphics) technology is a new revolutionary solution to overcome the existing problems in the current web technology. It provides precise and high-resolution web graphics using plain text format commands. It sets a new standard for web graphic format to allow us to present complicated graphics with rich test fonts and colors, high printing quality, and dynamic layout capabilities. This paper provides a tutorial overview about SVG technology and its essential features, capability, and advantages. The reports a comparison studies between SVG and other web graphics technologies.

  7. Web 3.0 Emerging

    SciTech Connect

    Hendler, James

    2012-02-22

    As more and more data and information becomes available on the Web, new technologies that use explicit semantics for information organization are becoming desirable. New terms such as Linked Data, Semantic Web and Web 3.0 are used more and more, although there is increasing confusion as to what each means. In this talk, I will describe how different sorts of models can be used to link data in different ways. I will particularly explore different kinds of Web applications, from Enterprise Data Integration to Web 3.0 startups, government data release, the different needs of Web 2.0 and 3.0, the growing interest in “semantic search”, and the underlying technologies that power these new approaches.

  8. Value of Information Web Application

    DTIC Science & Technology

    2015-04-01

    their understanding of VoI attributes (source reliable , information content, and latency). The VoI web application emulates many features of a...built to allow the tool to be accessed from the Internet via a web browser. The following sections describe the web application’s user interface...based upon 3 attributes: source reliable , information content, and latency. The cards are divided into 4 decks: training, tactical, strategic, and

  9. Genetic toxicology: web resources.

    PubMed

    Young, Robert R

    2002-04-25

    Genetic toxicology is the scientific discipline dealing with the effects of chemical, physical and biological agents on the heredity of living organisms. The Internet offers a wide range of online digital resources for the field of Genetic Toxicology. The history of genetic toxicology and electronic data collections are reviewed. Web-based resources at US National Library of Medicine (NLM), including MEDLINE, PUBMED, Gateway, Entrez, and TOXNET, are discussed. Search strategies and Medical Subject Headings (MeSH) are reviewed in the context of genetic toxicology. The TOXNET group of databases are discussed with emphasis on those databases with genetic toxicology content including GENE-TOX, TOXLINE, Hazardous Substances Data Bank, Integrated Risk Information System, and Chemical Carcinogenesis Research Information System. Location of chemical information including chemical structure and linkage to health and regulatory information using CHEMIDPLUS at NLM and other databases is reviewed. Various government agencies have active genetic toxicology research programs or use genetic toxicology data to assist fulfilling the agency's mission. Online resources at the US Food and Drug Administration (FDA), the US Environmental Protection Agency (EPA), the National Institutes of Environmental Health Sciences, and the National Toxicology Program (NTP) are outlined. Much of the genetic toxicology for pharmaceuticals, industrial chemicals and pesticides that is performed in the world is regulatory-driven. Regulatory web resources are presented for the laws mandating testing, guidelines on study design, Good Laboratory Practice (GLP) regulations, and requirements for electronic data collection and reporting. The Internet provides a range of other supporting resources to the field of genetic toxicology. The web links for key professional societies and journals in genetic toxicology are listed. Distance education, educational media resources, and job placement services are also

  10. Pleiotropic Phenotypes of the sticky peel Mutant Provide New Insight into the Role of CUTIN DEFICIENT2 in Epidermal Cell Function in Tomato1[W][OA

    PubMed Central

    Nadakuduti, Satya Swathi; Pollard, Mike; Kosma, Dylan K.; Allen, Charles; Ohlrogge, John B.; Barry, Cornelius S.

    2012-01-01

    Plant epidermal cells have evolved specialist functions associated with adaptation to stress. These include the synthesis and deposition of specialized metabolites such as waxes and cutin together with flavonoids and anthocyanins, which have important roles in providing a barrier to water loss and protection against UV radiation, respectively. Characterization of the sticky peel (pe) mutant of tomato (Solanum lycopersicum) revealed several phenotypes indicative of a defect in epidermal cell function, including reduced anthocyanin accumulation, a lower density of glandular trichomes, and an associated reduction in trichome-derived terpenes. In addition, pe mutant fruit are glossy and peels have increased elasticity due to a severe reduction in cutin biosynthesis and altered wax deposition. Leaves of the pe mutant are also cutin deficient and the epicuticular waxes contain a lower proportion of long-chain alkanes. Direct measurements of transpiration, together with chlorophyll-leaching assays, indicate increased cuticular permeability of pe leaves. Genetic mapping revealed that the pe locus represents a new allele of CUTIN DEFICIENT2 (CD2), a member of the class IV homeodomain-leucine zipper gene family, previously only associated with cutin deficiency in tomato fruit. CD2 is preferentially expressed in epidermal cells of tomato stems and is a homolog of Arabidopsis (Arabidopsis thaliana) ANTHOCYANINLESS2 (ANL2). Analysis of cuticle composition in leaves of anl2 revealed that cutin accumulates to approximately 60% of the levels observed in wild-type Arabidopsis. Together, these data provide new insight into the role of CD2 and ANL2 in regulating diverse metabolic pathways and in particular, those associated with epidermal cells. PMID:22623518

  11. Pleiotropic phenotypes of the sticky peel mutant provide new insight into the role of CUTIN DEFICIENT2 in epidermal cell function in tomato.

    PubMed

    Nadakuduti, Satya Swathi; Pollard, Mike; Kosma, Dylan K; Allen, Charles; Ohlrogge, John B; Barry, Cornelius S

    2012-07-01

    Plant epidermal cells have evolved specialist functions associated with adaptation to stress. These include the synthesis and deposition of specialized metabolites such as waxes and cutin together with flavonoids and anthocyanins, which have important roles in providing a barrier to water loss and protection against UV radiation, respectively. Characterization of the sticky peel (pe) mutant of tomato (Solanum lycopersicum) revealed several phenotypes indicative of a defect in epidermal cell function, including reduced anthocyanin accumulation, a lower density of glandular trichomes, and an associated reduction in trichome-derived terpenes. In addition, pe mutant fruit are glossy and peels have increased elasticity due to a severe reduction in cutin biosynthesis and altered wax deposition. Leaves of the pe mutant are also cutin deficient and the epicuticular waxes contain a lower proportion of long-chain alkanes. Direct measurements of transpiration, together with chlorophyll-leaching assays, indicate increased cuticular permeability of pe leaves. Genetic mapping revealed that the pe locus represents a new allele of CUTIN DEFICIENT2 (CD2), a member of the class IV homeodomain-leucine zipper gene family, previously only associated with cutin deficiency in tomato fruit. CD2 is preferentially expressed in epidermal cells of tomato stems and is a homolog of Arabidopsis (Arabidopsis thaliana) ANTHOCYANINLESS2 (ANL2). Analysis of cuticle composition in leaves of anl2 revealed that cutin accumulates to approximately 60% of the levels observed in wild-type Arabidopsis. Together, these data provide new insight into the role of CD2 and ANL2 in regulating diverse metabolic pathways and in particular, those associated with epidermal cells.

  12. Gauging the Success of Your Web Site

    ERIC Educational Resources Information Center

    Goldsborough, Reid

    2005-01-01

    Web analytics is a way to measure and optimize Web site performance, says Jason Burby, director of Web analytics for ZAAZ Inc., a Web design and development firm in Seattle with a countrywide client base. He compares it to using Evite, which is a useful, free web service that makes it easy to send out party and other invitations and,…

  13. Methodologies for Crawler Based Web Surveys.

    ERIC Educational Resources Information Center

    Thelwall, Mike

    2002-01-01

    Describes Web survey methodologies used to study the content of the Web, and discusses search engines and the concept of crawling the Web. Highlights include Web page selection methodologies; obstacles to reliable automatic indexing of Web sites; publicly indexable pages; crawling parameters; and tests for file duplication. (Contains 62…

  14. Web Searching: Innovations, Challenges, and Future Directions.

    ERIC Educational Resources Information Center

    Su, Louise T.

    2000-01-01

    Presents an outline for a planned technical session discussing innovations in the Web, the current state of Web searching, challenges, and future directions. Highlights include search engines; an empirical comparison of Web site overview techniques; Federal statistics web sites; and an evaluation of Web search engines from the end-user's…

  15. Collaborative Authoring on the Web: Introducing WebDAV.

    ERIC Educational Resources Information Center

    Whitehead, E. James, Jr.

    1998-01-01

    Discusses the WebDAV Distributed Authoring Protocol which provides standards that allow easier collaborative authoring over the World Wide Web. Topics include Hypertext Transfer Protocol (HTTP), overwrite prevention, access control, searching, metadata, XML (Extensible Markup Language), and Uniform Resource Identifier (URI). (LRW)

  16. Improving query services of web map by web mining

    NASA Astrophysics Data System (ADS)

    Huang, Maojun

    2007-11-01

    Web map is the hybrid of map and the World Wide Web (known as Web). It is usually created with WebGIS techniques. With the rapid social development, web maps oriented the public are facing pressure that dissatisfy the increased demanding. The geocoding database plays a key role in supporting query services effectively. The traditional geocoding method is laborious and time-consuming. And there is much online spatial information, which would be the supplementary information source for geocoding. Therefore, this paper discusses how to improve query services by web mining. The improvement can be described from three facets: first, improving location query by discovering and extracting address information from the Web to extend geocoding database. Second, enhancing the ability of optimum path query of public traffic and buffer query by spatial analyzing and reasoning on the extended geocoding database. Third, adjusting strategies of collecting data according to patterns discovered by web map query mining. Finally, this paper presents the designing of the application system and experimental results.

  17. Restructuring Web Site Design: An Alternative to WebTeams.

    ERIC Educational Resources Information Center

    Davis, Marc; Boyer, Janice

    In July 1997, the University Library at the University of Nebraska at Omaha adopted a new structural model for Web site development--the publishing metaphor. Rather than relying on an individual expert (the Webmaster) or a WebTeam comprised of a few individuals, the model permits everyone in the organization, regardless of position or Web…

  18. Web-Based Course Management and Web Services

    ERIC Educational Resources Information Center

    Mandal, Chittaranjan; Sinha, Vijay Luxmi; Reade, Christopher M. P.

    2004-01-01

    The architecture of a web-based course management tool that has been developed at IIT [Indian Institute of Technology], Kharagpur and which manages the submission of assignments is discussed. Both the distributed architecture used for data storage and the client-server architecture supporting the web interface are described. Further developments…

  19. Metadata for Web Resources: How Metadata Works on the Web.

    ERIC Educational Resources Information Center

    Dillon, Martin

    This paper discusses bibliographic control of knowledge resources on the World Wide Web. The first section sets the context of the inquiry. The second section covers the following topics related to metadata: (1) definitions of metadata, including metadata as tags and as descriptors; (2) metadata on the Web, including general metadata systems,…

  20. Work of the Web Weavers: Web Development in Academic Libraries

    ERIC Educational Resources Information Center

    Bundza, Maira; Vander Meer, Patricia Fravel; Perez-Stable, Maria A.

    2009-01-01

    Although the library's Web site has become a standard tool for seeking information and conducting research in academic institutions, there are a variety of ways libraries approach the often challenging--and sometimes daunting--process of Web site development and maintenance. Three librarians at Western Michigan University explored issues related…

  1. Bringing Web 2.0 to Web Lectures

    ERIC Educational Resources Information Center

    Ketterl, Markus; Mertens, Robert; Vornberger, Oliver

    2009-01-01

    Purpose: At many universities, web lectures have become an integral part of the e-learning portfolio over the last few years. While many aspects of the technology involved, like automatic recording techniques or innovative interfaces for replay, have evolved at a rapid pace, web lecturing has remained independent of other important developments…

  2. Science on the Web: Web Activities Using Scientific Data.

    ERIC Educational Resources Information Center

    Poppe, Barbara; McAlister, Deborah; Richardson, Lisa

    This guide is intended to help teachers learn about using special software tools for the World Wide Web. It makes use of the scientific data produced by the National Oceanic and Atmospheric Administration (NOAA) and other government agencies. Activities in this booklet include: (1) "Finding People in Cyberspace"; (2) "Finding Science on the Web";…

  3. Tele diagnostic by web

    NASA Astrophysics Data System (ADS)

    Sugiyama, Shigeki

    2006-03-01

    Because of the development of multimedia technologies like Web and Internet, it now becomes possible to think about Tele Medicine and Tele Diagnostic for a distant place where no doctors and no nurses are situated at or are available. And also some kind of intelligence can be added onto them, which makes possible to give certain kind of medical treatment assistance or suggestions for a patient from a computer diagnostic base through the Internetworking. For doing this, here considers about a basic system of "Tele Diagnostic for a remote place" where it dose not have a doctor and a medical assistance. In order to implement the system, JAVA, VRML, HTML, and CORTONA are used as a basic language and a viewer. And also in order to add a kind of intelligence, Augmented Knowledge In Agent (AKIA) by using Back Propagation Neural Networks (BPNN) is used. And by this study, here can introduce the system that has the following basic mechanisms; By inputting physical data like temperature or blood pressure, the system would show a diagnostic assistance by TEXT. And also the bad place of body would be shown graphically if there were any. The system can be put onto Web, so that anybody could have this assistance at any place ubiquitously only if a person has Internetworking access.

  4. FPA Depot - Web Application

    NASA Technical Reports Server (NTRS)

    Avila, Edwin M. Martinez; Muniz, Ricardo; Szafran, Jamie; Dalton, Adam

    2011-01-01

    Lines of code (LOC) analysis is one of the methods used to measure programmer productivity and estimate schedules of programming projects. The Launch Control System (LCS) had previously used this method to estimate the amount of work and to plan development efforts. The disadvantage of using LOC as a measure of effort is that one can only measure 30% to 35% of the total effort of software projects involves coding [8]. In the application, instead of using the LOC we are using function point for a better estimation of hours in each software to develop. Because of these disadvantages, Jamie Szafran of the System Software Branch of Control And Data Systems (NE-C3) at Kennedy Space Canter developed a web application called Function Point Analysis (FPA) Depot. The objective of this web application is that the LCS software architecture team can use the data to more accurately estimate the effort required to implement customer requirements. This paper describes the evolution of the domain model used for function point analysis as project managers continually strive to generate more accurate estimates.

  5. Web Search Studies: Multidisciplinary Perspectives on Web Search Engines

    NASA Astrophysics Data System (ADS)

    Zimmer, Michael

    Perhaps the most significant tool of our internet age is the web search engine, providing a powerful interface for accessing the vast amount of information available on the world wide web and beyond. While still in its infancy compared to the knowledge tools that precede it - such as the dictionary or encyclopedia - the impact of web search engines on society and culture has already received considerable attention from a variety of academic disciplines and perspectives. This article aims to organize a meta-discipline of “web search studies,” centered around a nucleus of major research on web search engines from five key perspectives: technical foundations and evaluations; transaction log analyses; user studies; political, ethical, and cultural critiques; and legal and policy analyses.

  6. 75 FR 27986 - Electronic Filing System-Web (EFS-Web) Contingency Option

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-19

    ... United States Patent and Trademark Office Electronic Filing System--Web (EFS-Web) Contingency Option..., Electronic Filing System--Web (EFS-Web) by providing a new contingency option when the primary portal to EFS-Web has an unscheduled outage. Previously, the entire EFS-Web system is not available to the...

  7. Web2Quests: Updating a Popular Web-Based Inquiry-Oriented Activity

    ERIC Educational Resources Information Center

    Kurt, Serhat

    2009-01-01

    WebQuest is a popular inquiry-oriented activity in which learners use Web resources. Since the creation of the innovation, almost 15 years ago, the Web has changed significantly, while the WebQuest technique has changed little. This article examines possible applications of new Web trends on WebQuest instructional strategy. Some possible…

  8. Working with WebQuests: Making the Web Accessible to Students with Disabilities.

    ERIC Educational Resources Information Center

    Kelly, Rebecca

    2000-01-01

    This article describes how students with disabilities in regular classes are using the WebQuest lesson format to access the Internet. It explains essential WebQuest principles, creating a draft Web page, and WebQuest components. It offers an example of a WebQuest about salvaging the sunken ships, Titanic and Lusitania. A WebQuest planning form is…

  9. Interacting Science through Web Quests

    ERIC Educational Resources Information Center

    Unal, Ahmet; Karakus, Melek Altiparmak

    2016-01-01

    The purpose of this paper is to examine the effects of WebQuests on elementary students' science achievement, attitude towards science and attitude towards web supported education in teaching 7th grade subjects (Ecosystems, Solar System). With regard to this research, "Science Achievement Test," "Attitude towards Science Scale"…

  10. Web conferencing in online classrooms.

    PubMed

    Hart, Leigh

    2014-01-01

    Web conferencing is a promising tool for online education. A well-developed teaching strategy can lead to effective use of this technology to create a sense of community, engage students, and promote academic integrity in online courses. This article presents strategies for integrating Web conferencing into online nursing courses.

  11. Distance Education Clearinghouse Web Site.

    ERIC Educational Resources Information Center

    Adams, Kate; Martin, Sara

    A World Wide Web site, developed by University of Nebraska-Lincoln Information Services staff and funded by a NEB*SAT (Nebraska's multiple channel satellite and optical fiber educational telecommunications network) grant, provides a clearinghouse of distance education, Internet, and Web page development information that is useful to librarians and…

  12. New Generation Sensor Web Enablement

    PubMed Central

    Bröring, Arne; Echterhoff, Johannes; Jirka, Simon; Simonis, Ingo; Everding, Thomas; Stasch, Christoph; Liang, Steve; Lemmens, Rob

    2011-01-01

    Many sensor networks have been deployed to monitor Earth’s environment, and more will follow in the future. Environmental sensors have improved continuously by becoming smaller, cheaper, and more intelligent. Due to the large number of sensor manufacturers and differing accompanying protocols, integrating diverse sensors into observation systems is not straightforward. A coherent infrastructure is needed to treat sensors in an interoperable, platform-independent and uniform way. The concept of the Sensor Web reflects such a kind of infrastructure for sharing, finding, and accessing sensors and their data across different applications. It hides the heterogeneous sensor hardware and communication protocols from the applications built on top of it. The Sensor Web Enablement initiative of the Open Geospatial Consortium standardizes web service interfaces and data encodings which can be used as building blocks for a Sensor Web. This article illustrates and analyzes the recent developments of the new generation of the Sensor Web Enablement specification framework. Further, we relate the Sensor Web to other emerging concepts such as the Web of Things and point out challenges and resulting future work topics for research on Sensor Web Enablement. PMID:22163760

  13. Digging Deeper: The Deep Web.

    ERIC Educational Resources Information Center

    Turner, Laura

    2001-01-01

    Focuses on the Deep Web, defined as Web content in searchable databases of the type that can be found only by direct query. Discusses the problems of indexing; inability to find information not indexed in the search engine's database; and metasearch engines. Describes 10 sites created to access online databases or directly search them. Lists ways…

  14. Advanced dendritic web growth development

    NASA Technical Reports Server (NTRS)

    Hopkins, R. H.

    1985-01-01

    A program to develop the technology of the silicon dendritic web ribbon growth process is examined. The effort is being concentrated on the area rate and quality requirements necessary to meet the JPL/DOE goals for terrestrial PV applications. Closed loop web growth system development and stress reduction for high area rate growth is considered.

  15. Parent-Friendly Web Pages.

    ERIC Educational Resources Information Center

    Farmer, Lesley S. J.

    2000-01-01

    Discusses how librarians can help parents become more knowledgeable about the Internet so they can guide their children in Internet use and become technologically independent. Recommends that school libraries develop Web pages that parents can access and discusses Web page design, content for children, and content for parents. (LRW)

  16. Web Page Design (Part Three).

    ERIC Educational Resources Information Center

    Descy, Don E.

    1997-01-01

    Discusses fonts as well as design considerations that should be reviewed when designing World Wide Web pages and sites to make them easier for clients to use and easier to maintain. Also discusses the simplicity of names; organization of pages, folders, and files; and sites to help build Web sites. (LRW)

  17. Image Searching across the Web.

    ERIC Educational Resources Information Center

    Pack, Thomas

    2002-01-01

    Discusses how to find digital images on the Web. Considers images and copyright; provides an overview of the search capabilities of six search engines, including AltaVista, Google, AllTheWeb.com, Ditto.com, Picsearch, and Lycos; and describes specialized image search engines. (LRW)

  18. Web Accessibility and Accessibility Instruction

    ERIC Educational Resources Information Center

    Green, Ravonne A.; Huprich, Julia

    2009-01-01

    Section 508 of the Americans with Disabilities Act (ADA) mandates that programs and services be accessible to people with disabilities. While schools of library and information science (SLIS*) and university libraries should model accessible Web sites, this may not be the case. This article examines previous studies about the Web accessibility of…

  19. Web Service: MedlinePlus

    MedlinePlus

    ... this page: https://medlineplus.gov/webservices.html MedlinePlus Web Service To use the sharing features on this ... please enable JavaScript. MedlinePlus offers a search-based Web service that provides access to MedlinePlus health topic ...

  20. Critical Reading of the Web

    ERIC Educational Resources Information Center

    Griffin, Teresa; Cohen, Deb

    2012-01-01

    The ubiquity and familiarity of the world wide web means that students regularly turn to it as a source of information. In doing so, they "are said to rely heavily on simple search engines, such as Google to find what they want." Researchers have also investigated how students use search engines, concluding that "the young web users tended to…

  1. NASA: Data on the Web.

    ERIC Educational Resources Information Center

    Galica, Carol

    1997-01-01

    Provides an annotated bibliography of selected NASA Web sites for K-12 math and science teachers: the NASA Lewis Research Center Learning Technologies K-12 Home Page, Spacelink, NASA Quest, Basic Aircraft Design Page, International Space Station, NASA Shuttle Web Site, LIFTOFF to Space Education, Telescopes in Education, and Space Educator's…

  2. Working with WebQuests

    ERIC Educational Resources Information Center

    Raulston, Cassie; Moellinger, Donna

    2007-01-01

    With the evolution of technology, students can now take online classes that may not be offered in their home schools. While online courses are commonly found in many high schools, WebQuests are used more commonly in elementary schools. Through the exploration of WebQuests, students are able to integrate the Internet into classroom activities. The…

  3. Web Tools: The Second Generation

    ERIC Educational Resources Information Center

    Pascopella, Angela

    2008-01-01

    Web 2.0 tools and technologies, or second generation tools, help districts to save time and money, and eliminate the need to transfer or move files back and forth across computers. Many Web 2.0 tools help students think critically and solve problems, which falls under the 21st-century skills. The second-generation tools are growing in popularity…

  4. Group Learning on the Web

    ERIC Educational Resources Information Center

    Alant, E.; Dada, S.

    2005-01-01

    This paper examines the issues of syndicate learning in a web-based environment. The multi-professional Master's degree in Early Childhood Intervention is described and discussed in terms of its philosophy of multi-professional small group learning. A description of the processes involved in facilitating web-based learning in small groups is…

  5. The Great Lakes Food Web.

    ERIC Educational Resources Information Center

    Baker, Marjane L.

    1997-01-01

    Presents a play for students in grades four to nine that incorporates the scientific names, physical characteristics, feeding habits, interactions, and interdependence of the plants and animals that make up the Great Lakes food web to facilitate the learning of this complex system. Includes a Great Lakes food web chart. (AIM)

  6. The Web and School Counseling

    ERIC Educational Resources Information Center

    Carey, John; Dimmitt, Carey

    2005-01-01

    The Web and related technologies are creating a revolution in the practice of school counseling. This paper describes emerging trends and identifies critical issues that need to be addressed to facilitate increased use. The article summarizes current uses and identifies ways the Web can be used to improve practice and professional competence. To…

  7. Staleness Among Web Search Engines.

    ERIC Educational Resources Information Center

    Koehler, Wallace

    1998-01-01

    Describes a study of four major Web search engines that tested for staleness, a condition when a significant number of the hits it returns point to Web pages or server-level domains (SLD) that are no longer viable. Results of tests of URLs with AltaVista, HotBot, InfoSeek, and Open Text are discussed. (Author/LRW)

  8. Thin film-coated polymer webs

    DOEpatents

    Wenz, Robert P.; Weber, Michael F.; Arudi, Ravindra L.

    1992-02-04

    The present invention relates to thin film-coated polymer webs, and more particularly to thin film electronic devices supported upon a polymer web, wherein the polymer web is treated with a purifying amount of electron beam radiation.

  9. Course Development on the World Wide Web.

    ERIC Educational Resources Information Center

    King, Kathleen P.

    1998-01-01

    Guidelines for developing Web-based course materials include considerations of available resources, how technology aids in meeting curricular goals and objectives, Web-site design and construction, and Web-course evaluation. (SK)

  10. The EMBRACE web service collection

    PubMed Central

    Pettifer, Steve; Ison, Jon; Kalaš, Matúš; Thorne, Dave; McDermott, Philip; Jonassen, Inge; Liaquat, Ali; Fernández, José M.; Rodriguez, Jose M.; Partners, INB-; Pisano, David G.; Blanchet, Christophe; Uludag, Mahmut; Rice, Peter; Bartaseviciute, Edita; Rapacki, Kristoffer; Hekkelman, Maarten; Sand, Olivier; Stockinger, Heinz; Clegg, Andrew B.; Bongcam-Rudloff, Erik; Salzemann, Jean; Breton, Vincent; Attwood, Teresa K.; Cameron, Graham; Vriend, Gert

    2010-01-01

    The EMBRACE (European Model for Bioinformatics Research and Community Education) web service collection is the culmination of a 5-year project that set out to investigate issues involved in developing and deploying web services for use in the life sciences. The project concluded that in order for web services to achieve widespread adoption, standards must be defined for the choice of web service technology, for semantically annotating both service function and the data exchanged, and a mechanism for discovering services must be provided. Building on this, the project developed: EDAM, an ontology for describing life science web services; BioXSD, a schema for exchanging data between services; and a centralized registry (http://www.embraceregistry.net) that collects together around 1000 services developed by the consortium partners. This article presents the current status of the collection and its associated recommendations and standards definitions. PMID:20462862

  11. Web Platform Application

    SciTech Connect

    Paulsworth, Ashley; Kurtz, Jim; Brun de Pontet, Stephanie

    2016-06-15

    Sunvestment Energy Group (previously called Sunvestment Group) was established to create a web application that brings together site hosts, those who will obtain the energy from the solar array, with project developers and funders, including affinity investors. Sunvestment Energy Group (SEG) uses a community-based model that engages with investors who have some affinity with the site host organization. In addition to a financial return, these investors receive non-financial value from their investments and are therefore willing to offer lower cost capital. This enables the site host to enjoy more savings from solar through these less expensive Community Power Purchase Agreements (CPPAs). The purpose of this award was to develop an online platform to bring site hosts and investors together virtually.

  12. Web life: Hyperphysics

    NASA Astrophysics Data System (ADS)

    2009-05-01

    So what is the site about? Hyperphysics is a network of cross-linked articles on topics from acceleration to the Zeeman effect - essentially an online physics encyclopedia. Unlike some sites featured in this column, Hyperphysics is far from new. In fact, by Web standards, it is positively ancient; when it was launched back in 1998 as a "hyperphysics exploration environment", the search engine Google was still based in a California garage. Today, Google's algorithms place Hyperphysics entries near the top of results pages for most physics-related search terms - it receives some three million hits per year - and some readers may already have stumbled across the site while searching for physics information on the Internet.

  13. Web Site Development Support

    NASA Technical Reports Server (NTRS)

    Abdul, Hameed

    2016-01-01

    This summer I assisted the RPT Program Office in developing a design plan to update their existing website to current NASA web standards. The finished website is intended for the general public, specifically potential customers interested in learning about NASA's chemical rocket test facility capabilities and test assignment process. The goal of the website is to give the public insight about the purpose and function of the RPT Program. Working on this project gave me the opportunity to learn skills necessary for effective project management. The RPT Program Office manages numerous facilities so they are required to travel often to other sites for meetings throughout the year. Maneuvering around the travel schedule of the office and the workload priority of the IT Department proved to be quite the challenge. I overcame the travel schedule of the office by frequently communicating and checking in with my mentor via email and telephone.

  14. Critical Path Web Site

    NASA Technical Reports Server (NTRS)

    Robinson, Judith L.; Charles, John B.; Rummel, John A. (Technical Monitor)

    2000-01-01

    Approximately three years ago, the Agency's lead center for the human elements of spaceflight (the Johnson Space Center), along with the National Biomedical Research Institute (NSBRI) (which has the lead role in developing countermeasures) initiated an activity to identify the most critical risks confronting extended human spaceflight. Two salient factors influenced this activity: first, what information is needed to enable a "go/no go" decision to embark on extended human spaceflight missions; and second, what knowledge and capabilities are needed to address known and potential health, safety and performance risks associated with such missions. A unique approach was used to first define and assess those risks, and then to prioritize them. This activity was called the Critical Path Roadmap (CPR) and it represents an opportunity to develop and implement a focused and evolving program of research and technology designed from a "risk reduction" perspective to prevent or minimize the risks to humans exposed to the space environment. The Critical Path Roadmap provides the foundation needed to ensure that human spaceflight, now and in the future, is as safe, productive and healthy as possible (within the constraints imposed on any particular mission) regardless of mission duration or destination. As a tool, the Critical Path Roadmap enables the decisionmaker to select from among the demonstrated or potential risks those that are to be mitigated, and the completeness of that mitigation. The primary audience for the CPR Web Site is the members of the scientific community who are interested in the research and technology efforts required for ensuring safe and productive human spaceflight. They may already be informed about the various space life sciences research programs or they may be newcomers. Providing the CPR content to potential investigators increases the probability of their delivering effective risk mitigations. Others who will use the CPR Web Site and its content

  15. Critical Path Web Site

    NASA Technical Reports Server (NTRS)

    Robinson, Judith L.; Charles, John B.; Rummel, John A. (Technical Monitor)

    2000-01-01

    Approximately three years ago, the Agency's lead center for the human elements of spaceflight (the Johnson Space Center), along with the National Biomedical Research Institute (NSBRI) (which has the lead role in developing countermeasures) initiated an activity to identify the most critical risks confronting extended human spaceflight. Two salient factors influenced this activity: first, what information is needed to enable a "go/no go" decision to embark on extended human spaceflight missions; and second, what knowledge and capabilities are needed to address known and potential health, safety and performance risks associated with such missions. A unique approach was used to first define and assess those risks, and then to prioritize them. This activity was called the Critical Path Roadmap (CPR) and it represents an opportunity to develop and implement a focused and evolving program of research and technology designed from a "risk reduction" perspective to prevent or minimize the risks to humans exposed to the space environment. The Critical Path Roadmap provides the foundation needed to ensure that human spaceflight, now and in the future, is as safe, productive and healthy as possible (within the constraints imposed on any particular mission) regardless of mission duration or destination. As a tool, the Critical Path Roadmap enables the decision maker to select from among the demonstrated or potential risks those that are to be mitigated, and the completeness of that mitigation. The primary audience for the CPR Web Site is the members of the scientific community who are interested in the research and technology efforts required for ensuring safe and productive human spaceflight. They may already be informed about the various space life sciences research programs or they may be newcomers. Providing the CPR content to potential investigators increases the probability of their delivering effective risk mitigations. Others who will use the CPR Web Site and its

  16. Diet-induced co-variation between architectural and physicochemical plasticity in an extended phenotype.

    PubMed

    Blamires, Sean J; Hasemore, Matthew; Martens, Penny J; Kasumovic, Michael M

    2017-03-01

    The adaptive benefits of extended phenotypic plasticity are imprecisely defined due to a paucity of experiments examining traits that are manipulable and measurable across environments. Spider webs are often used as models to explore the adaptive benefits of variations in extended phenotypes across environments. Nonetheless, our understanding of the adaptive nature of the plastic responses of spider webs is impeded when web architectures and silk physicochemical properties appear to co-vary. An opportunity to examine this co-variation is presented by modifying prey items while measuring web architectures and silk physiochemical properties. Here, we performed two experiments to assess the nature of the association between web architectures and gluey silk properties when the orb web spider Argiope keyserlingi was fed a diet that varied in either mass and energy or prey size and feeding frequency. We found web architectures and gluey silk physicochemical properties to co-vary across treatments in both experiments. Specifically, web capture area co-varied with gluey droplet morphometrics, thread stickiness and salt concentrations when prey mass and energy were manipulated, and spiral spacing co-varied with gluey silk salt concentrations when prey size and feeding frequency were manipulated. We explained our results as A. keyserlingi plastically shifting its foraging strategy as multiple prey parameters simultaneously varied. We confirmed and extended previous work by showing that spiders use a variety of prey cues to concurrently adjust web and silk traits across different feeding regimes.

  17. The Web as an API.

    SciTech Connect

    Roman, J. H.

    2001-01-01

    As programmers we have worked with many Application Development Interface API development kits. They are well suited for interaction with a particular system. A vast source of information can be made accessible by using the http protocol through the web as an API. This setup has many advantages including the vast knowledge available on setting web servers and services. Also, these tools are available on most hardware and operating system combinations. In this paper I will cover the various types of systems that can be developed this way, their advantages and some drawbacks of this approach. Index Terms--Application Programmer Interface, Distributed applications, Hyper Text Transfer Protocol, Web.

  18. Interstellar Initiative Web Page Design

    NASA Technical Reports Server (NTRS)

    Mehta, Alkesh

    1999-01-01

    This summer at NASA/MSFC, I have contributed to two projects: Interstellar Initiative Web Page Design and Lenz's Law Relative Motion Demonstration. In the Web Design Project, I worked on an Outline. The Web Design Outline was developed to provide a foundation for a Hierarchy Tree Structure. The Outline would help design a Website information base for future and near-term missions. The Website would give in-depth information on Propulsion Systems and Interstellar Travel. The Lenz's Law Relative Motion Demonstrator is discussed in this volume by Russell Lee.

  19. RESTful Web Services at BNL

    SciTech Connect

    Casella, R.

    2011-06-14

    RESTful (REpresentational State Transfer) web services are an alternative implementation to SOAP/RPC web services in a client/server model. BNLs IT Division has started deploying RESTful Web Services for enterprise data retrieval and manipulation. Data is currently used by system administrators for tracking configuration information and as it is expanded will be used by Cyber Security for vulnerability management and as an aid to cyber investigations. This talk will describe the implementation and outstanding issues as well as some of the reasons for choosing RESTful over SOAP/RPC and future directions.

  20. A Web Information Retrieval System

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Hyun; Park, Dong-Chul; Huh, Woong; Kim, Hyen-Ug; Yoon, Chung-Hwa; Park, Chong-Dae; Woo, Dong-Min; Jeong, Taikyeong; Cho, Il-Hwan; Lee, Yunsik

    An approach for the retrieval of price information from internet sites is applied to real-world application problems in this paper. The Web Information Retrieval System (WIRS) utilizes Hidden Markov Model (HMM) for its powerful capability to process temporal information. HMM is an extremely flexible tool and has been successfully applied to a wide variety of stochastic modeling tasks. In order to compare the prices and features of products from various web sites, the WIRS extracts prices and descriptions of various products within web pages. The WIRS is evaluated with real-world problems and compared with a conventional method and the result is reported in this paper.

  1. Sticky ions in biological systems.

    PubMed Central

    Collins, K D

    1995-01-01

    Aqueous gel sieving chromatography on Sephadex G-10 of the Group IA cations (Li+, Na+, K+, Rb+, Cs+) plus NH4+ as the Cl- salts, in combination with previous results for the halide anions (F-, Cl-, Br-, I-) as the Na+ salts [Washabaugh, M.W. & Collins, K.D. (1986) J. Biol. Chem. 261, 12477-12485], leads to the following conclusions. (i) The small monovalent ions (Li+, Na+, F-) flow through the gel with water molecules attached, whereas the large monovalent ions (K+, Rb+, Cs+, Cl-, Br-, I-) adsorb to the nonpolar surface of the gel, a process requiring partial dehydration of the ion and implying that these ions bind the immediately adjacent water molecules weakly. (ii) The transition from strong to weak hydration occurs at a radius of about 1.78 A for the monovalent anions, compared with a radius of about 1.06 A for the monovalent cations (using ionic radii), indicating that the anions are more strongly hydrated than the cations for a given charge density. (iii) The anions show larger deviations from ideal behavior (an elution position corresponding to the anhydrous molecular weight) than do the cations and dominate the chromatographic behavior of the neutral salts. These results are interpreted to mean that weakly hydrated ions (chaotropes) are "pushed" onto weakly hydrated surfaces by strong water-water interactions and that the transition from strong ionic hydration to weak ionic hydration occurs where the strength of ion-water interactions approximately equals the strength of water-water interactions in bulk solution. PMID:7539920

  2. String and Sticky Tape Experiments.

    ERIC Educational Resources Information Center

    Edge, R. D., Ed.

    1984-01-01

    Experiments which illustrate the effect of humidity on human hair and on paper are described. Also described are two ways to make a hygrometer. These methods were found in a series of British television programs (also available in the United States). Comments on the programs are included. (JN)

  3. New web technologies for astronomy

    NASA Astrophysics Data System (ADS)

    Sprimont, P.-G.; Ricci, D.; Nicastro, L.

    2014-12-01

    Thanks to the new HTML5 capabilities and the huge improvements of the JavaScript language, it is now possible to design very complex and interactive web user interfaces. On top of that, the once monolithic and file-server oriented web servers are evolving into easily programmable server applications capable to cope with the complex interactions made possible by the new generation of browsers. We believe that the whole community of amateur and professionals astronomers can benefit from the potential of these new technologies. New web interfaces can be designed to provide the user with a large deal of much more intuitive and interactive tools. Accessing astronomical data archives, schedule, control and monitor observatories, and in particular robotic telescopes, supervising data reduction pipelines, all are capabilities that can now be implemented in a JavaScript web application. In this paper we describe the Sadira package we are implementing exactly to this aim.

  4. Sustainable Materials Management Web Academy

    EPA Pesticide Factsheets

    The Sustainable Materials Management (SMM) Web Academy series is a free resource for SMM challenge participants, stakeholders, and anyone else interested in learning more about SMM principles from experts in the field.

  5. Social Web and Knowledge Management

    NASA Astrophysics Data System (ADS)

    Dolog, Peter; Krötzsch, Markus; Schaffert, Sebastian; Vrandečić, Denny

    Knowledge Management is the study and practice of representing, communicating, organizing, and applying knowledge in organizations. Moreover, being used by organizations, it is inherently social. The Web, as a medium, enables new forms of communications and interactions and requires new ways to represent knowledge assets. It is therefore obvious that the Web will influence and change Knowledge Management, but it is very unclear what the impact of these changes will be. This chapter raises questions and discusses visions in the area that connects the Social Web and Knowledge Management - an area of research that is only just emerging. The World Wide Web conference 2008 in Beijing hosted a workshop on that question, bringing together researchers and practitioners to gain first insights toward answering questions of that area.

  6. Corporate Web Sites in Traditional Print Advertisements.

    ERIC Educational Resources Information Center

    Pardun, Carol J.; Lamb, Larry

    1999-01-01

    Describes the Web presence in print advertisements to determine how marketers are creating bridges between traditional advertising and the Internet. Content analysis showed Web addresses in print ads; categories of advertisers most likely to link print ads with Web sites; and whether the Web site attempts to develop a database of potential…

  7. Challenges of Web-Based Assessment.

    ERIC Educational Resources Information Center

    Luecht, Richard M.

    This paper discusses six challenges relevant to Web-based testing. Some of these challenges are not specific to Web-based testing, but generalize to all computer-based testing. The challenges are: (1) security and using test centers for Web-based testing; (2) measuring complex skills and problem-solving tasks on the Web; (3) integrating modern…

  8. The Semantic Web in Teacher Education

    ERIC Educational Resources Information Center

    Czerkawski, Betül Özkan

    2014-01-01

    The Semantic Web enables increased collaboration among computers and people by organizing unstructured data on the World Wide Web. Rather than a separate body, the Semantic Web is a functional extension of the current Web made possible by defining relationships among websites and other online content. When explicitly defined, these relationships…

  9. Technical Services and the World Wide Web.

    ERIC Educational Resources Information Center

    Scheschy, Virginia M.

    The World Wide Web and browsers such as Netscape and Mosaic have simplified access to electronic resources. Today, technical services librarians can share in the wealth of information available on the Web. One of the premier Web sites for acquisitions librarians is AcqWeb, a cousin of the AcqNet listserv. In addition to interesting news items,…

  10. Improving Web Accessibility in a University Setting

    ERIC Educational Resources Information Center

    Olive, Geoffrey C.

    2010-01-01

    Improving Web accessibility for disabled users visiting a university's Web site is explored following the World Wide Web Consortium (W3C) guidelines and Section 508 of the Rehabilitation Act rules for Web page designers to ensure accessibility. The literature supports the view that accessibility is sorely lacking, not only in the USA, but also…

  11. Extracting Macroscopic Information from Web Links.

    ERIC Educational Resources Information Center

    Thelwall, Mike

    2001-01-01

    Discussion of Web-based link analysis focuses on an evaluation of Ingversen's proposed external Web Impact Factor for the original use of the Web, namely the interlinking of academic research. Studies relationships between academic hyperlinks and research activities for British universities and discusses the use of search engines for Web link…

  12. Web Page Design and Network Analysis.

    ERIC Educational Resources Information Center

    Wan, Hakman A.; Chung, Chi-wai

    1998-01-01

    Examines problems in Web-site design from the perspective of network analysis. In view of the similarity between the hypertext structure of Web pages and a generic network, network analysis presents concepts and theories that provide insight for Web-site design. Describes the problem of home-page location and control of number of Web pages and…

  13. NASA and The Semantic Web

    NASA Technical Reports Server (NTRS)

    Ashish, Naveen

    2005-01-01

    We provide an overview of several ongoing NASA endeavors based on concepts, systems, and technology from the Semantic Web arena. Indeed NASA has been one of the early adopters of Semantic Web Technology and we describe ongoing and completed R&D efforts for several applications ranging from collaborative systems to airspace information management to enterprise search to scientific information gathering and discovery systems at NASA.

  14. CMMI on the Web: Remastered

    DTIC Science & Technology

    2009-09-01

    strategic partners with their sponsoring government agencies What is an FFRDC 5 SEPG AP 2009 CMMI on the Web: Remastered © 2009 Carnegie Mellon...Video),  www.sei.cmu.edu/library/abstracts/videos/cmmisvc.cfm Constellations - 5 10 SEPG AP 2009 CMMI on the Web: Remastered © 2009 Carnegie Mellon...2009 Carnegie Mellon University Maturity Levels: 1 – Initial 2 – Managed 3 – Defined 4 – Quantitatively Managed 5 – Optimizing • Used in Staged

  15. TREC 2013 Web Track Overview

    DTIC Science & Technology

    2014-01-30

    relative to a provided baseline). Second, we based the 2013 Web track experiments on the new ClueWeb12 collection created by the Language Technologies...sophisticated stages of retrieval in their quest to improve result quality: from personalized and contextual re-ranking to automatic query reformulation ...B manual 0.045 0.058 0.038 6 Acknowledgements We thank Jamie Callan, David Pane and the Language Technologies Insti- tute at Carnegie Mellon

  16. Mashups over the Deep Web

    NASA Astrophysics Data System (ADS)

    Hornung, Thomas; Simon, Kai; Lausen, Georg

    Combining information from different Web sources often results in a tedious and repetitive process, e.g. even simple information requests might require to iterate over a result list of one Web query and use each single result as input for a subsequent query. One approach for this chained queries are data-centric mashups, which allow to visually model the data flow as a graph, where the nodes represent the data source and the edges the data flow.

  17. The design and implementation of web mining in web sites security

    NASA Astrophysics Data System (ADS)

    Li, Jian; Zhang, Guo-Yin; Gu, Guo-Chang; Li, Jian-Li

    2003-06-01

    The backdoor or information leak of Web servers can be detected by using Web Mining techniques on some abnormal Web log and Web application log data. The security of Web servers can be enhanced and the damage of illegal access can be avoided. Firstly, the system for discovering the patterns of information leakages in CGI scripts from Web log data was proposed. Secondly, those patterns for system administrators to modify their codes and enhance their Web site security were provided. The following aspects were described: one is to combine web application log with web log to extract more information, so web data mining could be used to mine web log for discovering the information that firewall and Information Detection System cannot find. Another approach is to propose an operation module of web site to enhance Web site security. In cluster server session, Density-Based Clustering technique is used to reduce resource cost and obtain better efficiency.

  18. Past, Present, and Future of Web Service

    NASA Astrophysics Data System (ADS)

    Kitamura, Yasuhiko

    World Wide Web was born as a means to provide information through the Internet. As a number of e-shopping sites are developed on the Internet, the Web provides not only information but also services with which users can interact to buy products. This paper describes the basic standards used in Web service; XML, SOAP, and WSDL, and how Web services are implemented on the Java-based platform Axis. It also mentions the REST-based Web service which gains more attention recently. Finally it forecasts the future of Web service from a viewpoint of Semantic Web.

  19. Evaluation and Criteria of the World Wide Web: Reference Web Sites.

    ERIC Educational Resources Information Center

    Csir, Floyd J.

    This paper applies an evaluation method for World Wide Web sites that provide access to online reference materials at academic and public libraries. The evaluation of Web sites was performed with a questionnaire form focusing on Web site currency, accuracy and relevancy; Web site organization/structure; Web site presentation; URL maintenance; and…

  20. Administering GBrowse sites with WebGBrowse.

    PubMed

    Podicheti, Ram; Dong, Qunfeng

    2011-03-01

    GBrowse is widely used by biologists to visualize genome annotation. We have developed WebGBrowse to facilitate hosting multiple GBrowse instances specific for different users on the same Web server. WebGBrowse automatically sets up each user-specific GBrowse instance by extracting information from user-supplied data to produce the appropriate configuration. This unit describes installation and administration of WebGBrowse for bioinformaticians who plan to manage local WebGBrowse servers in their institutions.

  1. WebAlchemist: a Web transcoding system for mobile Web access in handheld devices

    NASA Astrophysics Data System (ADS)

    Whang, Yonghyun; Jung, Changwoo; Kim, Jihong; Chung, Sungkwon

    2001-11-01

    In this paper, we describe the design and implementation of WebAlchemist, a prototype web transcoding system, which automatically converts a given HTML page into a sequence of equivalent HTML pages that can be properly displayed on a hand-held device. The Web/Alchemist system is based on a set of HTML transcoding heuristics managed by the Transcoding Manager (TM) module. In order to tackle difficult-to-transcode pages such as ones with large or complex table structures, we have developed several new transcoding heuristics that extract partial semantics from syntactic information such as the table width, font size and cascading style sheet. Subjective evaluation results using popular HTML pages (such as the CNN home page) show that WebAlchemist generates readable, structure-preserving transcoded pages, which can be properly displayed on hand-held devices.

  2. IsoWeb: a bayesian isotope mixing model for diet analysis of the whole food web.

    PubMed

    Kadoya, Taku; Osada, Yutaka; Takimoto, Gaku

    2012-01-01

    Quantitative description of food webs provides fundamental information for the understanding of population, community, and ecosystem dynamics. Recently, stable isotope mixing models have been widely used to quantify dietary proportions of different food resources to a focal consumer. Here we propose a novel mixing model (IsoWeb) that estimates diet proportions of all consumers in a food web based on stable isotope information. IsoWeb requires a topological description of a food web, and stable isotope signatures of all consumers and resources in the web. A merit of IsoWeb is that it takes into account variation in trophic enrichment factors among different consumer-resource links. Sensitivity analysis using realistic hypothetical food webs suggests that IsoWeb is applicable to a wide variety of food webs differing in the number of species, connectance, sample size, and data variability. Sensitivity analysis based on real topological webs showed that IsoWeb can allow for a certain level of topological uncertainty in target food webs, including erroneously assuming false links, omission of existent links and species, and trophic aggregation into trophospecies. Moreover, using an illustrative application to a real food web, we demonstrated that IsoWeb can compare the plausibility of different candidate topologies for a focal web. These results suggest that IsoWeb provides a powerful tool to analyze food-web structure from stable isotope data. We provide R and BUGS codes to aid efficient applications of IsoWeb.

  3. Drought rewires the cores of food webs

    NASA Astrophysics Data System (ADS)

    Lu, Xueke; Gray, Clare; Brown, Lee E.; Ledger, Mark E.; Milner, Alexander M.; Mondragón, Raúl J.; Woodward, Guy; Ma, Athen

    2016-09-01

    Droughts are intensifying across the globe, with potentially devastating implications for freshwater ecosystems. We used new network science approaches to investigate drought impacts on stream food webs and explored potential consequences for web robustness to future perturbations. The substructure of the webs was characterized by a core of richly connected species surrounded by poorly connected peripheral species. Although drought caused the partial collapse of the food webs, the loss of the most extinction-prone peripheral species triggered a substantial rewiring of interactions within the networks’ cores. These shifts in species interactions in the core conserved the underlying core/periphery substructure and stability of the drought-impacted webs. When we subsequently perturbed the webs by simulating species loss in silico, the rewired drought webs were as robust as the larger, undisturbed webs. Our research unearths previously unknown compensatory dynamics arising from within the core that could underpin food web stability in the face of environmental perturbations.

  4. Firefly: embracing future web technologies

    NASA Astrophysics Data System (ADS)

    Roby, W.; Wu, X.; Goldina, T.; Joliet, E.; Ly, L.; Mi, W.; Wang, C.; Zhang, Lijun; Ciardi, D.; Dubois-Felsmann, G.

    2016-07-01

    At IPAC/Caltech, we have developed the Firefly web archive and visualization system. Used in production for the last eight years in many missions, Firefly gives the scientist significant capabilities to study data. Firefly provided the first completely web based FITS viewer as well as a growing set of tabular and plotting visualizers. Further, it will be used for the science user interface of the LSST telescope which goes online in 2021. Firefly must meet the needs of archive access and visualization for the 2021 LSST telescope and must serve astronomers beyond the year 2030. Recently, our team has faced the fact that the technology behind Firefly software was becoming obsolete. We were searching for ways to utilize the current breakthroughs in maintaining stability, testability, speed, and reliability of large web applications, which Firefly exemplifies. In the last year, we have ported the Firefly to cutting edge web technologies. Embarking on this massive overhaul is no small feat to say the least. Choosing the technologies that will maintain a forward trajectory in a future development project is always hard and often overwhelming. When a team must port 150,000 lines of code for a production-level product there is little room to make poor choices. This paper will give an overview of the most modern web technologies and lessons learned in our conversion from GWT based system to React/Redux based system.

  5. DIRAC: Secure web user interface

    NASA Astrophysics Data System (ADS)

    Casajus Ramo, A.; Sapunov, M.

    2010-04-01

    Traditionally the interaction between users and the Grid is done with command line tools. However, these tools are difficult to use by non-expert users providing minimal help and generating outputs not always easy to understand especially in case of errors. Graphical User Interfaces are typically limited to providing access to the monitoring or accounting information and concentrate on some particular aspects failing to cover the full spectrum of grid control tasks. To make the Grid more user friendly more complete graphical interfaces are needed. Within the DIRAC project we have attempted to construct a Web based User Interface that provides means not only for monitoring the system behavior but also allows to steer the main user activities on the grid. Using DIRAC's web interface a user can easily track jobs and data. It provides access to job information and allows performing actions on jobs such as killing or deleting. Data managers can define and monitor file transfer activity as well as check requests set by jobs. Production managers can define and follow large data productions and react if necessary by stopping or starting them. The Web Portal is build following all the grid security standards and using modern Web 2.0 technologies which allow to achieve the user experience similar to the desktop applications. Details of the DIRAC Web Portal architecture and User Interface will be presented and discussed.

  6. Intelligent web image retrieval system

    NASA Astrophysics Data System (ADS)

    Hong, Sungyong; Lee, Chungwoo; Nah, Yunmook

    2001-07-01

    Recently, the web sites such as e-business sites and shopping mall sites deal with lots of image information. To find a specific image from these image sources, we usually use web search engines or image database engines which rely on keyword only retrievals or color based retrievals with limited search capabilities. This paper presents an intelligent web image retrieval system. We propose the system architecture, the texture and color based image classification and indexing techniques, and representation schemes of user usage patterns. The query can be given by providing keywords, by selecting one or more sample texture patterns, by assigning color values within positional color blocks, or by combining some or all of these factors. The system keeps track of user's preferences by generating user query logs and automatically add more search information to subsequent user queries. To show the usefulness of the proposed system, some experimental results showing recall and precision are also explained.

  7. Analysis of Web Proxy Logs

    NASA Astrophysics Data System (ADS)

    Fei, Bennie; Eloff, Jan; Olivier, Martin; Venter, Hein

    Network forensics involves capturing, recording and analysing network audit trails. A crucial part of network forensics is to gather evidence at the server level, proxy level and from other sources. A web proxy relays URL requests from clients to a server. Analysing web proxy logs can give unobtrusive insights to the browsing behavior of computer users and provide an overview of the Internet usage in an organisation. More importantly, in terms of network forensics, it can aid in detecting anomalous browsing behavior. This paper demonstrates the use of a self-organising map (SOM), a powerful data mining technique, in network forensics. In particular, it focuses on how a SOM can be used to analyse data gathered at the web proxy level.

  8. Project Assessment Skills Web Application

    NASA Technical Reports Server (NTRS)

    Goff, Samuel J.

    2013-01-01

    The purpose of this project is to utilize Ruby on Rails to create a web application that will replace a spreadsheet keeping track of training courses and tasks. The goal is to create a fast and easy to use web application that will allow users to track progress on training courses. This application will allow users to update and keep track of all of the training required of them. The training courses will be organized by group and by user, making readability easier. This will also allow group leads and administrators to get a sense of how everyone is progressing in training. Currently, updating and finding information from this spreadsheet is a long and tedious task. By upgrading to a web application, finding and updating information will be easier than ever as well as adding new training courses and tasks. Accessing this data will be much easier in that users just have to go to a website and log in with NDC credentials rather than request the relevant spreadsheet from the holder. In addition to Ruby on Rails, I will be using JavaScript, CSS, and jQuery to help add functionality and ease of use to my web application. This web application will include a number of features that will help update and track progress on training. For example, one feature will be to track progress of a whole group of users to be able to see how the group as a whole is progressing. Another feature will be to assign tasks to either a user or a group of users. All of these together will create a user friendly and functional web application.

  9. Workspaces in the Semantic Web

    NASA Technical Reports Server (NTRS)

    Wolfe, Shawn R.; Keller, RIchard M.

    2005-01-01

    Due to the recency and relatively limited adoption of Semantic Web technologies. practical issues related to technology scaling have received less attention than foundational issues. Nonetheless, these issues must be addressed if the Semantic Web is to realize its full potential. In particular, we concentrate on the lack of scoping methods that reduce the size of semantic information spaces so they are more efficient to work with and more relevant to an agent's needs. We provide some intuition to motivate the need for such reduced information spaces, called workspaces, give a formal definition, and suggest possible methods of deriving them.

  10. WebTag: Web Browsing into Sensor Tags over NFC

    PubMed Central

    Echevarria, Juan Jose; Ruiz-de-Garibay, Jonathan; Legarda, Jon; Álvarez, Maite; Ayerbe, Ana; Vazquez, Juan Ignacio

    2012-01-01

    Information and Communication Technologies (ICTs) continue to overcome many of the challenges related to wireless sensor monitoring, such as for example the design of smarter embedded processors, the improvement of the network architectures, the development of efficient communication protocols or the maximization of the life cycle autonomy. This work tries to improve the communication link of the data transmission in wireless sensor monitoring. The upstream communication link is usually based on standard IP technologies, but the downstream side is always masked with the proprietary protocols used for the wireless link (like ZigBee, Bluetooth, RFID, etc.). This work presents a novel solution (WebTag) for a direct IP based access to a sensor tag over the Near Field Communication (NFC) technology for secure applications. WebTag allows a direct web access to the sensor tag by means of a standard web browser, it reads the sensor data, configures the sampling rate and implements IP based security policies. It is, definitely, a new step towards the evolution of the Internet of Things paradigm. PMID:23012511

  11. WebTag: Web browsing into sensor tags over NFC.

    PubMed

    Echevarria, Juan Jose; Ruiz-de-Garibay, Jonathan; Legarda, Jon; Alvarez, Maite; Ayerbe, Ana; Vazquez, Juan Ignacio

    2012-01-01

    Information and Communication Technologies (ICTs) continue to overcome many of the challenges related to wireless sensor monitoring, such as for example the design of smarter embedded processors, the improvement of the network architectures, the development of efficient communication protocols or the maximization of the life cycle autonomy. This work tries to improve the communication link of the data transmission in wireless sensor monitoring. The upstream communication link is usually based on standard IP technologies, but the downstream side is always masked with the proprietary protocols used for the wireless link (like ZigBee, Bluetooth, RFID, etc.). This work presents a novel solution (WebTag) for a direct IP based access to a sensor tag over the Near Field Communication (NFC) technology for secure applications. WebTag allows a direct web access to the sensor tag by means of a standard web browser, it reads the sensor data, configures the sampling rate and implements IP based security policies. It is, definitely, a new step towards the evolution of the Internet of Things paradigm.

  12. WebMIRS: web-based medical information retrieval system

    NASA Astrophysics Data System (ADS)

    Long, L. Rodney; Pillemer, Stanley R.; Lawrence, Reva C.; Goh, Gin-Hua; Neve, Leif; Thoma, George R.

    1997-12-01

    At the Lister Hill National Center for Biomedical Communications, a research and development division of the National Library of Medicine (NLM), we are developing a prototype multimedia database system to provide World Wide Web access to biomedical databases. WebMIRS (Web-based Medical Information Retrieval System) will allow access to databases containing text and images and will allow database query by standard SQL, by image content, or by a combination of the two. The system is being developed in the form of Java applets, which will communicate with the Informix DBMS on an NLM Sun workstation running the Solaris operating system. The system architecture will allow access from any hardware platform, which supports a Java-enabled Web browser, such as Netscape or Internet Explorer. Initial databases will include data from two national health surveys conducted by the National Center for Health Statistics (NCHS), and will include x-ray images from those surveys. In addition to describing in- house research in database access systems, this paper describes ongoing work toward querying by image content. Image content search capability will include capability to search for x-ray images similar to an input image with respect to vertebral morphometry used to characterize features such as fractures and disc space narrowing.

  13. Web Portal for Multicast Delivery Management.

    ERIC Educational Resources Information Center

    Mannaert, H.; De Gruyter, B.; Adriaenssens, P.

    2003-01-01

    Presents a Web portal for multicast communication management, which provides fully automatic service management with integrated provisioning of hardware equipment. Describes the software architecture, the implementation, and the application usage of the Web portal for multicast delivery. (Author/AEF)

  14. ERLN WebEDR Fact Sheet

    EPA Pesticide Factsheets

    The Web-based Electronic Data Review (WebEDR) application performs automated data evaluation on ERLN electronic data deliverables (EDDs). It uses test derived from the National Functional Guidelines combined with method-defined limits to measure data.

  15. Water Quality Exchange Web Template User Guide

    EPA Pesticide Factsheets

    This is a step by step guide to using the WQX Web Monitoring Data Entry Template for Physical/Chemical data to prepare your data for import into the WQX Web tool, and subsequent transfer to the STORET Data Warehouse.

  16. The Web site your doctor prescribes

    MedlinePlus

    ... Navigation Bar Home Current Issue Past Issues The Web site your doctor prescribes Past Issues / Summer 2008 ... gov® is a free, comprehensive, up-to-date Web site with health information from the world's largest ...

  17. The Web site your doctor prescribes

    MedlinePlus

    ... Navigation Bar Home Current Issue Past Issues The Web site your doctor prescribes Past Issues / Summer 2006 ... gov ® is a free, comprehensive, up-to-date Web site with health information from the world's largest ...

  18. Thematic World Wide Web Visualization System

    SciTech Connect

    1996-10-10

    WebTheme is a system designed to facilitate world wide web information access and retrieval through visualization. It consists of two principal pieces, a WebTheme Server which allows users to enter in a query and automatocally harvest and process information of interest, and a WebTheme browser, which allows users to work with both Galaxies and Themescape visualizations of their data within a JAVA capable world wide web browser. WebTheme is an Internet solution, meaning that access to the server and the resulting visualizations can all be performed through the use of a WWW browser. This allows users to access and interact with SPIRE (Spatial Paradigm for Information Retrieval and Exploration) based visualizations through a web browser regardless of what computer platforms they are running on. WebTheme is specifically designed to create databases by harvesting and processing WWW home pages available on the Internet.

  19. Narcissism and social networking Web sites.

    PubMed

    Buffardi, Laura E; Campbell, W Keith

    2008-10-01

    The present research examined how narcissism is manifested on a social networking Web site (i.e., Facebook.com). Narcissistic personality self-reports were collected from social networking Web page owners. Then their Web pages were coded for both objective and subjective content features. Finally, strangers viewed the Web pages and rated their impression of the owner on agentic traits, communal traits, and narcissism. Narcissism predicted (a) higher levels of social activity in the online community and (b) more self-promoting content in several aspects of the social networking Web pages. Strangers who viewed the Web pages judged more narcissistic Web page owners to be more narcissistic. Finally, mediational analyses revealed several Web page content features that were influential in raters' narcissistic impressions of the owners, including quantity of social interaction, main photo self-promotion, and main photo attractiveness. Implications of the expression of narcissism in social networking communities are discussed.

  20. Climate change: A rewired food web

    NASA Astrophysics Data System (ADS)

    Blanchard, Julia L.

    2015-11-01

    Climate change is causing large fish species to move into arctic marine environments. A network analysis finds that these fishes, with their generalist diets, add links to the existing food web that may alter biodiversity and web stability.

  1. World Wide Web Homepage Design.

    ERIC Educational Resources Information Center

    Tillman, Michael L.

    This paper examines hypermedia design and draws conclusions about how educational research and theory applies to various aspects of World Wide Web (WWW) homepage design. "Hypermedia" is defined as any collection of information which may be textual, graphical, visual, or auditory in nature and which may be accessed via a nonlinear route.…

  2. Learning through Web Page Design.

    ERIC Educational Resources Information Center

    Peel, Deborah

    2001-01-01

    Describes and evaluates the use of Web page design in an undergraduate course in the United Kingdom on town planning. Highlights include incorporating information and communication technologies into higher education; and a theoretical framework for the use of educational technology. (LRW)

  3. Semantic Search of Web Services

    ERIC Educational Resources Information Center

    Hao, Ke

    2013-01-01

    This dissertation addresses semantic search of Web services using natural language processing. We first survey various existing approaches, focusing on the fact that the expensive costs of current semantic annotation frameworks result in limited use of semantic search for large scale applications. We then propose a vector space model based service…

  4. WEB-WAP based telecare.

    PubMed Central

    DeLeo, Gianluca; Krishna, Santosh; Balas, E. Andrew; Maglaveras, Nicos; Boren, Suzanne Austin; Beltrame, Francesco; Fato, Marco

    2002-01-01

    We have developed two telecare applications based on mobile telephony (WAP) and WEB. The first can be used to request Basic Life Support (BLS) guidelines any time by using a WAP device and to teach people and non-professionals involved in health care emergency situations. The second is a WEB-WAP based tool for medical data retrieval and at-home health care monitoring of chronically ill patients with congestive heart failure (CHF) or diabetes. Medical education content related to these diseases is available on the WEB and on the WAP device. The WAP application uses the features found in the last generation of mobile phones such as better multimedia information presentations, better interactivity capabilities, and enhanced ease of use. Based on these two applications, a promising platform is offered for developing applications in health care, home care, medical monitoring and health education ensuring continuity of care. In the paper we present the preliminary results of a pilot test at Thessaloniki University (Greece) where the WEB-WAP based tool is used to monitor patients with diabetes or CHF. PMID:12463815

  5. Higher Education on the Web.

    ERIC Educational Resources Information Center

    Lee, John

    2001-01-01

    The investment in information technology has doubled for colleges over the last 10 years, and the next big evolution, the development of Web-based learning, is well underway. Most colleges and universities have a strategic plan for distance education or are developing one. The effort is led by community colleges and private universities, both of…

  6. Accessible Multimedia for the Web.

    ERIC Educational Resources Information Center

    Zaparyniuk, Nicholas; Code, Jillianne

    With the Internet taking a dominant role in corporate training, education, retail, and customer based product exploration, authors of Web-based information need to ensure that the media they deliver is accessible to the widest possible audience. Whether users have a visual, auditory, physical, or developmental disability, accessible multimedia can…

  7. Moving Reference to the Web.

    ERIC Educational Resources Information Center

    McGlamery, Susan; Coffman, Steve

    2000-01-01

    Explores the possibility of using Web contact center software to offer reference assistance to remote users. Discusses a project by the Metropolitan Cooperative Library System/Santiago Library System consortium to test contact center software and to develop a virtual reference network. (Author/LRW)

  8. Web Reference: A Virtual Reality.

    ERIC Educational Resources Information Center

    Foster, Janet

    1999-01-01

    Presents ideas and strategies to enhance digital reference services available via the Internet in public libraries. Describes print publications which include Web reference columns; subject guides, both print and online; and the resources of the Internet Public Library and other virtual reference desks. (LRW)

  9. ACCELERATION PHYSICS CODE WEB REPOSITORY.

    SciTech Connect

    WEI, J.

    2006-06-26

    In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this repository, illustrate its usage, and discuss our future plans, with emphasis on code benchmarking.

  10. Accelerator Physics Code Web Repository

    SciTech Connect

    Zimmermann, F.; Basset, R.; Bellodi, G.; Benedetto, E.; Dorda, U.; Giovannozzi, M.; Papaphilippou, Y.; Pieloni, T.; Ruggiero, F.; Rumolo, G.; Schmidt, F.; Todesco, E.; Zotter, B.W.; Payet, J.; Bartolini, R.; Farvacque, L.; Sen, T.; Chin, Y.H.; Ohmi, K.; Oide, K.; Furman, M.; /LBL, Berkeley /Oak Ridge /Pohang Accelerator Lab. /SLAC /TRIUMF /Tech-X, Boulder /UC, San Diego /Darmstadt, GSI /Rutherford /Brookhaven

    2006-10-24

    In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this repository, illustrate its usage, and discuss our future plans, with emphasis on code benchmarking.

  11. The Web in the West

    ERIC Educational Resources Information Center

    Betjeman, Kenneth Jon

    2005-01-01

    This paper is a history of the adoption and implementation of "The Web of Life", an inquiry based biology course for senior secondary students in Western Australia. It focuses on the period from 1965 to 1990, outlines the issues at the time, events, and timeline of implementation and reflects on inquiry teaching and learning. It is a…

  12. Legal Aspects of the Web.

    ERIC Educational Resources Information Center

    Borrull, Alexandre Lopez; Oppenheim, Charles

    2004-01-01

    Presents a literature review that covers the following topics related to legal aspects of the Web: copyright; domain names and trademarks; linking, framing, caching, and spamdexing; patents; pornography and censorship on the Internet; defamation; liability; conflict of laws and jurisdiction; legal deposit; and spam, i.e., unsolicited mails.…

  13. Web Page Design (Part One).

    ERIC Educational Resources Information Center

    Descy, Don E.

    1997-01-01

    Discusses rules for Web page design: consider audiences' Internet skills and equipment; know your content; outline the material; map or sketch the site; be consistent; regulate size of graphics to control download time; place eye catching material in the first 300 pixels; moderate use of color to control file size and bandwidth; include a…

  14. Biomechanical characterization of spider webs.

    PubMed

    Das, Rakesh; Kumar, Amit; Patel, Anurag; Vijay, Sahil; Saurabh, Shashank; Kumar, Navin

    2017-03-01

    In light of recent focus on the behaviour of the natural structures for revolutionary technological growth, spider web seems to have seized considerable attention of product designer due to its amazing behaviour. In present work, mechanism behind the structural integrity of the spider web along with the materialistic analysis of its constituent silk threads has been extensively investigated. The nanoindentation tool both in static and dynamic mode has been utilized for complete analysis of the mechanical behaviour of the spiral and radial threads separately. Both the average elastic modulus and hardness of the radial silk thread is higher than the spiral silk thread which reveals the radial silk thread is the major structural component of the web. The sustainability of spider webs under storm, windy conditions and during the impact of pray has been investigated under dynamic conditions. The radial silk thread exhibits elastic like response and the spiral silk thread exhibits viscous like response in a wide frequency range (1-200Hz). The damping characteristic of the radial and spiral silk threads, an important parameter to investigate the energy dissipation properties of the materials has also been investigated in windy conditions.

  15. Web-Based Slide Presentations.

    ERIC Educational Resources Information Center

    Just, Melissa L.

    At the University of Southern California's Norris Medical Library, seminars on World Wide Web topics are given to faculty, staff, students, and to community health care providers at remote sites. The presentations have been given using presentation software such as Microsoft PowerPoint, while running Netscape in the background, switching between…

  16. Design of Educational Web Pages

    ERIC Educational Resources Information Center

    Galan, Jose Gomez; Blanco, Soledad Mateos

    2004-01-01

    The methodological characteristics of teaching in primary and secondary education make it necessary to revise the pedagogical and instructive lines with which to introduce the new Information and Communication Technologies into the school context. The construction of Web pages that can be used to improve student learning is, therefore, fundamental…

  17. Managing Change on the Web.

    ERIC Educational Resources Information Center

    Francisco-Revilla, Luis; Shipman, Frank; Furuta, Richard; Karadkar, Unmil; Arora, Avital

    Increasingly, digital libraries are being defined as collection pointers to World Wide Web-based resources rather than collections that hold the resources themselves. Maintaining these collections is challenging due to distributed document ownership and high fluidity. Typically a collection's maintainer has to assess the relevance of changes with…

  18. The Web and Early Literacy

    ERIC Educational Resources Information Center

    Hillman, Marguerite; Moore, Terry

    2005-01-01

    The Web as an appropriate vehicle for educating young children in formal and informal school settings is the subject of widespread, international debate (Anderson, 2000; Attewell, Suazo-Garcia, & Battle, 2003; Davis & Shade, 1994; Dolowy, 2000; Filipenko & Rolfsen, 1999; Pendleton, 2001; Vail, 2001; Wardle, 1999). Regardless of these debates,…

  19. Exemplary Web-Based Schools

    ERIC Educational Resources Information Center

    Milone, Michael

    2005-01-01

    Exemplary Web-based schools are as different as they are similar. The schools featured in this section have applied technology in unique ways to meet the needs of their students. Five examples are cited across the U.S.: Lemon Grove School District, Lemon Grove, California; Virginia Beach City Public Schools, Virginia Beach, Virginia; Carlsbad…

  20. IT Security: Target: The Web

    ERIC Educational Resources Information Center

    Waters, John K.

    2009-01-01

    In December, Microsoft announced a major security flaw affecting its Internet Explorer web browser. The flaw allowed hackers to use hidden computer code they had already injected into legitimate websites to steal the passwords of visitors to those sites. Reportedly, more than 10,000 websites were infected with the destructive code by the time…