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Sample records for field evolved spinosad

  1. Susceptibility of spinosad in Musca domestica (Diptera: Muscidae) field populations.

    PubMed

    Kristensen, Michael; Jespersen, Jørgen B

    2004-06-01

    The toxicity of spinosad was determined in one susceptible and five insecticide-resistant laboratory strains of house fly, Musca domestica L. Spinosad was relatively slow-acting, but highly toxic to house flies. In a feeding bioassay, spinosad LC50 at 72 h was 0.51 microg of spinosad per gram of sugar, making it 6.3- and 3.5-fold more toxic to house flies compared with azamethiphos and methomyl, respectively. In topical application bioassay, the LD50 at 48 h of spinosad in susceptible house flies was 40 ng per 20 mg of house fly, making spinosad less toxic than the pyrethroid bioresmethrin synergized by piperonyl butoxide and the organophosphate dimethoate. The insecticide-resistant laboratory strains had resistance factors to spinosad at LC50 in feeding bioassay from 1.5 to 5.5 and at LD50 in topical application bioassay from 2.5 to 4.7, indicating that in house fly cross-resistance to the major insecticide classes will not initially be of major concern for the use of spinosad for house fly control. The toxicity of spinosad was also evaluated against 31 field populations of house flies collected from livestock farms across Denmark. The field populations were 2.2- to 7.5-fold resistant to spinosad at 72 h in feeding bioassay, but based on steep slopes in the bioassay and the limited variation of spinosad toxicity against the various field populations, we consider the field populations to be spinosad-susceptible. We propose a diagnostic dose of 12 microg of spinosad per gram of sugar in feeding bioassay with impregnated sugar for determination of resistant house flies, which is 10x the LC95 of the susceptible strain WHO and approximately = 2x the LD95 of the field populations. Spinosad showed no substantial cross-resistance to the pyrethroid bioresmethrin synergized by piperonyl butoxide, the anticholinesterases dimethoate, azamethiphos, methomyl, and spinosad in house fly field populations.

  2. Dissipation and residue of spinosad in zucchini under field conditions.

    PubMed

    Liu, Yanping; Sun, Haibin; Wang, Siwei

    2013-08-01

    The dissipation and residue of the insecticide spinosad in zucchini were investigated. An ultra-performance liquid chromatography-tandem mass spectrometry analytical method was developed for spinosad analysis. The half-lives of spinosad were 3.5-3.9 days in zucchini and 3.6-4.1 days in soil. The results showed that the dissipation rate of spinosad was fast, and it is suggested that a combination of rapid growth of zucchini, photodecomposition and the activity of soil microorganisms affected the dissipation rate of spinosad. The terminal residues of spinosad in zucchini were all below the quantification limit. No residue limit currently exists for spinosad in zucchini in China and other countries. Thus, the results can be useful in establishing a maximum residue limit.

  3. Impacts of spinosad and λ-cyhalothrin on spider communities in cabbage fields in south Texas.

    PubMed

    Liu, T-X; Irungu, R W; Dean, D A; Harris, M K

    2013-04-01

    Spiders are a principal arthropod group that preys on numerous pests of vegetables and other crops. In this study, we determined the effects of the two most commonly used insecticides, spinosad and λ-cyhalothrin, on diversity of spiders on cabbage in south Texas. In two seasons (fall 2008 and spring 2009), we collected a total of 588 spiders belonging to 53 species in 11 families from spinosad and λ-cyhalothrin-treated cabbages and the untreated control plants. A great majority of spiders were collected from the pitfall traps (554) where only a few (34) were collected from the blower/vacuum sampling. In the insecticide-treated plots, there were significantly fewer spider individuals, species and families than in untreated fields. Spinosad had significantly less effect on spiders in total individuals, number of species and families than λ-cyhalothrin. The effects of the two insecticides were further demonstrated by the Shannon-Weiner index (H') and the hierarchical richness index (HRI). Spider diversity in the spinosad-treated plots were not significantly different from that in the untreated fields but were greater than those in λ-cyhalothrin-treated plots in both seasons when measured by H' values. In contrast, the H' values of spider's diversity in the λ-cyhalothrin-treated plots were significantly lower than spinosad-treated and untreated plots. High values of HRI for spider richness in the spinosad-treated plots suggested that spinosad had less effect on spiders than λ-cyhalothrin. We concluded that spinosad was more compatible with spiders on cabbage compared to λ-cyhalothrin and that this information should be used when developing insecticide resistance management strategies.

  4. Residues, dissipation, and risk assessment of spinosad in cowpea under open field conditions.

    PubMed

    Huan, Zhibo; Luo, Jinhui; Xu, Zhi; Xie, Defang

    2015-11-01

    The dissipation and residues of an eco-friendly bio-pesticide, spinosad, in cowpea under field conditions were studied using ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MSMS) after Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction. The method exhibited good linearity with respect to spinosyn A and spinosyn D in solvent or blank cowpea matrix with correlation coefficients>0.99. Additionally, matrix effects were not significant in the range 0.987-1.014, and the average recoveries at three concentration levels were 75.1-91.1 and 79.4-90.5% for spinosyn A and spinosyn D, respectively. The intra- and inter-day relative standard deviations were 2.5-9.3 and 7.8-9.8% for spinosyn A, respectively, and 4.1-7.9 and 6.6-8.3% for spinosyn D, respectively. The limits of detection (LODs) and limits of quantification (LOQs) were 0.005 and 0.01 mg kg(-1), respectively, for spinosyn A, and 0.002 and 0.005 mg kg(-1), respectively, for spinosyn D. The dissipation of spinosad (sum of spinosyn A and spinosyn D) fitted well to first-order kinetics with half-lives of 0.9-1.5 days. The highest residue (HR) at pre-harvest interval (PHI) of 12 h was 0.321 mg kg(-1). Compared with the maximum residue limit (MRL) set by Codex, a PHI of at least 24 h was recommended. The estimated daily chronic intake of spinosad from cowpea was less than 0.14% of the acceptable daily intake (ADI). Therefore, the risk of consuming cowpea sprayed with spinosad under recommended field conditions was considered acceptable for the Chinese population. PMID:26502727

  5. Residues, dissipation, and risk assessment of spinosad in cowpea under open field conditions.

    PubMed

    Huan, Zhibo; Luo, Jinhui; Xu, Zhi; Xie, Defang

    2015-11-01

    The dissipation and residues of an eco-friendly bio-pesticide, spinosad, in cowpea under field conditions were studied using ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MSMS) after Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction. The method exhibited good linearity with respect to spinosyn A and spinosyn D in solvent or blank cowpea matrix with correlation coefficients>0.99. Additionally, matrix effects were not significant in the range 0.987-1.014, and the average recoveries at three concentration levels were 75.1-91.1 and 79.4-90.5% for spinosyn A and spinosyn D, respectively. The intra- and inter-day relative standard deviations were 2.5-9.3 and 7.8-9.8% for spinosyn A, respectively, and 4.1-7.9 and 6.6-8.3% for spinosyn D, respectively. The limits of detection (LODs) and limits of quantification (LOQs) were 0.005 and 0.01 mg kg(-1), respectively, for spinosyn A, and 0.002 and 0.005 mg kg(-1), respectively, for spinosyn D. The dissipation of spinosad (sum of spinosyn A and spinosyn D) fitted well to first-order kinetics with half-lives of 0.9-1.5 days. The highest residue (HR) at pre-harvest interval (PHI) of 12 h was 0.321 mg kg(-1). Compared with the maximum residue limit (MRL) set by Codex, a PHI of at least 24 h was recommended. The estimated daily chronic intake of spinosad from cowpea was less than 0.14% of the acceptable daily intake (ADI). Therefore, the risk of consuming cowpea sprayed with spinosad under recommended field conditions was considered acceptable for the Chinese population.

  6. Control of Tick Infestations in Oryctolagus cuniculus (Lagomorpha: Leporidae) With Spinosad Under Laboratory and Field Conditions.

    PubMed

    ValcÁrcel, Félix; SÁnchez, J L Pérez; Jaime, J M Tercero; Basco-Basco, P I; Guajardo, S C Cota; Cutuli, M T; GonzÁlez, J; Olmeda, A S

    2015-03-01

    Because of great economic loss in the world's livestock industry, and the serious risks to human health, the control of ticks and tick-borne diseases is one of the most important health management issues today. Current methodology involves integrated tick control for preventing the development of resistance. Rabbits are hosts for immature stages of the three-host tick Hyalomma lusitanicum Koch; so, we focus on this host as a strategy to interrupt the tick life cycle. Spinosad is an insecticide-acaricide, produced by the fermentation of metabolites of the actinomycete bacterium Saccharopolyspora spinosa. We administered spinosad orally by force-feeding naturally and artificially infested rabbits, and under field conditions by administering treated food via a hopper during the period of peak infestation and reinfestation risk for rabbits. No living larvae were recovered from treated laboratory rabbits. In naturally infested rabbits, the number of live ticks collected from treated rabbits (mean = 0.62 ticks per ear) was significantly lower than those recovered from untreated rabbits (mean = 7.27; P < 0.001), whereas the number of dead ticks collected from untreated rabbits (mean = 6.53) was significantly lower than those recovered from treated rabbits (mean = 18.62; P < 0.001). In addition, free and continually reinfested rabbits freely ingested low doses of spinosad, reducing the tick burden from 48.00 (Day 0) to 26.09 ticks per ear in treated rabbits (Day 16), whereas controls maintained the infection (46.64). This strategy could be useful as an alternative or supplement to traditional acaricides in tick control programs. PMID:26336305

  7. Variation in susceptibility of field strains of three stored grain insect species to spinosad and chlorpyrifos-methyl plus deltamethrin on hard red winter wheat.

    PubMed

    Sehgal, Blossom; Subramanyam, Bhadriraju; Arthur, Frank H; Gill, Bikram S

    2013-08-01

    Spinosad and chlorpyrifos-methyl plus deltamethrin efficacy at labeled rates on hard red winter wheat were evaluated against 11 field strains of the red flour beetle, Tribolium castaneum (Herbst); six strains of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.); and two strains of the lesser grain borer, Rhyzopertha dominica (F.), collected mostly from farm-stored grain in Kansas. Adults were exposed to wheat treated with spinosad at 1 mg (active ingredient)/kg or chlorpyrifos-methyl plus deltamethrin at three plus 0.5 mg (active ingredient)/kg. Adult mortality was assessed after 7 and 14 d and progeny production after 42 d. Spinosad did not provide complete mortality or progeny suppression of T. castaneum and O. surinamensis field strains, but was effective against R. dominica strains. Chlorpyrifos-methyl plus deltamethrin produced complete mortality and progeny suppression of field strains all three species. The two least susceptible T. castaneum and O. surinamensis strains and the two R. dominica strains were chosen for dose-response tests only with spinosad. The LD99 values for T. castaneum and R. dominica field strains were similar to that of the corresponding laboratory strains. Corresponding values for the two O. sturinamensis field strains were significantly greater (approximately 6 times) than the laboratory strain. The effective dose for progeny reduction (ED99) of only one R. dominica field strain was significantly greater (approximately 2 times) than the laboratory strain. The baseline susceptibility data of field strains of three insect species to spinosad will be useful for monitoring resistance development when this product is commercially released as a grain protectant.

  8. Magnetic fields around evolved stars

    NASA Astrophysics Data System (ADS)

    Leal-Ferreira, M.; Vlemmings, W.; Kemball, A.; Amiri, N.; Maercker, M.; Ramstedt, S.; Olofsson, G.

    2014-04-01

    A number of mechanisms, such as magnetic fields, (binary) companions and circumstellar disks have been suggested to be the cause of non-spherical PNe and in particular collimated outflows. This work investigates one of these mechanisms: the magnetic fields. While MHD simulations show that the fields can indeed be important, few observations of magnetic fields have been done so far. We used the VLBA to observe five evolved stars, with the goal of detecting the magnetic field by means of water maser polarization. The sample consists in four AGB stars (IK Tau, RT Vir, IRC+60370 and AP Lyn) and one pPN (OH231.8+4.2). In four of the five sources, several strong maser features were detected allowing us to measure the linear and/or circular polarization. Based on the circular polarization detections, we infer the strength of the component of the field along the line of sight to be between ~30 mG and ~330 mG in the water maser regions of these four sources. When extrapolated to the surface of the stars, the magnetic field strength would be between a few hundred mG and a few Gauss when assuming a toroidal field geometry and higher when assuming more complex magnetic fields. We conclude that the magnetic energy we derived in the water maser regions is higher than the thermal and kinetic energy, leading to the conclusion that, indeed, magnetic fields probably play an important role in shaping Planetary Nebulae.

  9. Cross resistances in spinosad-resistant Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Su, Tianyun; Cheng, Min-Lee

    2014-03-01

    A Culex quinquefasciatus Say colony was selected for 45 generations at LC70-90 levels using Natular XRG, a granular formulation of 2.5% spinosad for induction of spinosad resistance. Resistance to spinosad was noticed in early generations (F1-F9). Resistance levels increased gradually from generations F11-F35, and elevated significantly from generation F37 through F47, when resistance ratios reached 2,845-2,907-fold at LC50 and 11,948-22,928-fold at LC90 The spinosad-resistant Cx. quinquefasciatus colony was found not to be cross-resistant to Bacillus thuringiensis israelensis (Bti), a combination of Bti and Bacillus sphaericus, methoprene, pyriproxyfen, diflubenzuron, novaluron, temephos, or imidacloprid. However, it showed various levels of cross-resistance to B. sphaericus, spinetoram, abamectin, and fipronil. Conversely, a laboratory colony of Cx. quinquefasciatus that is highly resistant to B. sphaericus did not show cross-resistance to spinosad and spinetoram. Field-collected and laboratory-selected Cx. quinquefasciatus that showed low to moderate resistance to methoprene did not show cross-resistance to spinosad and spinetoram. Mechanisms of cross-resistance among several biorational pesticides were discussed according to their modes of actions.

  10. Field evaluation in Thailand of spinosad, a larvicide derived from Saccharopolyspora spinosa (Actinomycetales) against Aedes aegypti (L.) larvae.

    PubMed

    Thavara, Usavadee; Tawatsin, Apiwat; Asavadachanukorn, Preecha; Mulla, Mir S

    2009-03-01

    Two formulations of spinosad, direct application tablet (DT) and 0.5% granules (GR), at 3 dosages (0.25, 0.5 and 1.0 mg/l) in 200-liter earthen jars were evaluated against the larvae of Aedes aegypti. Two water regimens were used in the jars: jar full all the time and a full jar in which half the volume of the water was removed and replaced at each assessment interval. All treatments and controls were replicated 4 times and challenged with cohorts of 25 third-instar larvae of Ae. aegypti at weekly intervals during the study. The number of pupal skins (indicating successful emergence of adults) in the treated and control regimens were counted 7 days post-addition and they were used to calculate inhibition of emergence (% IE) based on the original number of larvae used. The DT formulation at the highest concentration (1.0 mg/l) yielded 79-100% IE for 34 days in the full jars, efficacy declining beyond this period. However, the longevity of this dosage was much longer with 90-100% IE for 62 days post-treatment in the water exchange regimen. The target and manufacturer-recommended concentration of 0.5 mg/l of DT gave good control (92-100% IE) for 20 days, declining below 92% IE thereafter in full jars. This dose also yielded good control with IE of 97-100% for 27 days in the water exchange regimen. The 0.5% GR formulation at all 3 dosages showed higher efficacy and greater longevity in the jars than the DT. In the full jars, all 3 dosages produced IE of 76-100% for 55 days post-treatment. In the water exchange regimen, the efficacy and longevity were increased by about one week, up to 62 days post-treatment. It is clear that the DT formulation can be used effectively against Ae. aegypti larvae at a target dose of 0.5 mg/l in 200-liter jars. This dose can be increased to 1.0 mg/l if slightly longer residual activity is desired. In containers where water is consumed and more water added, the longevity of efficacy will be longer for the DT than in jars which remain full

  11. The effects of spinosad on Culex quinquefasciatus and three nontarget insect species.

    PubMed

    Jones, Owen M; Ottea, James

    2013-12-01

    Spinosad is a relatively new insecticide with a unique mode of action that is being evaluated for control of larval mosquitoes. Whereas a number of toxicological studies have measured effects of spinosad on various animals, few have been conducted on the effects of spinosad on nontarget, aquatic insect species. Such studies are important as these species might be found in the same environments as mosquito larvae targeted for control. A neighborhood pond was surveyed to find a representative species of mosquito as well as other common aquatic insects with which to examine susceptibility to spinosad and nontarget effects. The mosquito species chosen was Culex quinquefasciatus and the most common nontarget taxa were immature stages of a mayfly (Caenis sp., Ephemeroptera: Caenidae), a damselfly (Ischnura sp., Odonata: Coenagrionidae), and a dragonfly (Pachydiplax longipennis, Odonata: Libellulidae). Bioassays of mosquitoes from a reference susceptible strain (Sebring-S) and field collections of Cx. quinquefasciatus were used to determine susceptibility to spinosad. In addition, susceptibility was examined in nontarget taxa using spinosad concentrations corresponding to the LC50 of field-collected mosquitoes (0.031 ppm) and the maximum label rate (1.6 ppm) of spinosad (Natular EC). Susceptibility to spinosad did not differ between Sebring-S and field-collected mosquitoes. However, there was a marked difference in susceptibility among nontarget taxa. Susceptibility was greatest in Caenis sp., followed by Ischnura sp., and then P. longipennis. PMID:24551967

  12. Monitoring Resistance to Spinosad in the Melon Fly (Bactrocera cucurbitae) in Hawaii and Taiwan

    PubMed Central

    Hsu, Ju-Chun; Haymer, David S.; Chou, Ming-Yi; Feng, Hai-Tung; Chen, Hsaio-Han; Huang, Yu-Bing; Mau, Ronald F. L.

    2012-01-01

    Spinosad is a natural insecticide with desirable qualities, and it is widely used as an alternative to organophosphates for control of pests such as the melon fly, Bactrocera cucurbitae (Coquillett). To monitor the potential for development of resistance, information about the current levels of tolerance to spinosad in melon fly populations were established in this study. Spinosad tolerance bioassays were conducted using both topical applications and feeding methods on flies from field populations with extensive exposure to spinosad as well as from collections with little or no prior exposure. Increased levels of resistance were observed in flies from the field populations. Also, higher dosages were generally required to achieve specific levels of mortality using topical applications compared to the feeding method, but these levels were all lower than those used for many organophosphate-based food lures. Our information is important for maintaining effective programs for melon fly management using spinosad. PMID:22629193

  13. Variation in susceptibility of field strains of three stored grain insect species to spinosad and chlorpyrifos-methyl plus deltamethrin on hard red winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spinosad and chlorpyrifos-methyl plus deltamethrin efficacy at labeled rates on hard red winter wheat was evaluated against 11 strains of the red flour beetle, Tribolium castaneum (Herbst); six strains of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.); and two strains of the lesser grai...

  14. Horizontal Transfer of Spinosad in Coptotermes formosanus (Isoptera: Rhinotermitidae).

    PubMed

    Bhatta, D; Henderson, G

    2016-08-01

    Slow-acting and nonrepellent termiticides are possible candidates for nestmate to nestmate transfer called horizontal transfer. For the horizontal transfer study of spinosad, Coptotermes formosanus Shiraki was released in sand and soil at 1, 25, and 50 ppm Entrust(®) for 1 h and then mixed with healthy untreated termites for 21 d at the ratio of 1:1. Donor and recipient termites began to contact and groom each other immediately after release. Mortality of termites was recorded at 1, 3, 7, and 14 d after treatment. Spinosad was more effectively transferred in sand than in soil. In sand at 25 and 50 ppm, significantly high mortality of donors and recipients was observed after 7 d. When termites were exposed to treated soil at day 21, all three concentrations resulted in significantly higher mortality compared to the control. In our laboratory study, spinosad was effectively transferred by donor termites. Transfer of spinosad depended on its bioavailability and concentration. Further study is needed to address its effects against C. formosanus under field conditions.

  15. Horizontal Transfer of Spinosad in Coptotermes formosanus (Isoptera: Rhinotermitidae).

    PubMed

    Bhatta, D; Henderson, G

    2016-08-01

    Slow-acting and nonrepellent termiticides are possible candidates for nestmate to nestmate transfer called horizontal transfer. For the horizontal transfer study of spinosad, Coptotermes formosanus Shiraki was released in sand and soil at 1, 25, and 50 ppm Entrust(®) for 1 h and then mixed with healthy untreated termites for 21 d at the ratio of 1:1. Donor and recipient termites began to contact and groom each other immediately after release. Mortality of termites was recorded at 1, 3, 7, and 14 d after treatment. Spinosad was more effectively transferred in sand than in soil. In sand at 25 and 50 ppm, significantly high mortality of donors and recipients was observed after 7 d. When termites were exposed to treated soil at day 21, all three concentrations resulted in significantly higher mortality compared to the control. In our laboratory study, spinosad was effectively transferred by donor termites. Transfer of spinosad depended on its bioavailability and concentration. Further study is needed to address its effects against C. formosanus under field conditions. PMID:27207263

  16. Metallomics - An Interdisciplinary and Evolving Field

    SciTech Connect

    Koppenaal, David W.; Hieftje, Gary M.

    2007-09-14

    In an editorial earlier this year (JAAS, 22, 111, 2007), we opined that metallomics, the study of metals in biological systems, would be an increasingly important topic in elemental analysis in general and for this journal in particular . This issue of the journal, co-edited by the two of us, is a second special issue covering the subject of Metallomics (the first issue was JAAS, 19/1, 2004). The present issue is comprised of technique, application, and perspective papers that address this emerging field of study and show how atomic spectrometry is contributing to the understanding of biological systems. The subjects covered range from metal binding in plants through investigations of metal and metalloids in samples of biological fluids to the study of food supplements and drug interactions in cells. The issue includes two Critical Reviews. Yuxi Gao and colleagues discuss advanced nuclear analytical techniques for the emerging field of metalloproteomics. While Laura Liermann and her colleagues consider how micro-organisms extract metals from minerals in the environment for utilization in metabolic processes. The content of some of these papers stretches the traditional boundaries and scope of this journal, as echoed by the reviewers of some of the papers. This discussion about scope requires perhaps further debate. However, it is our view that while the Journal must remain true to its core aims, it must also strive to accommodate and motivate a wider authorship and readership. Metallomics is a field that transcends biology and microbiology, biochemistry, clinical chemistry, environmental chemistry, geochemistry, and yes, atomic spectroscopy. If JAAS aspires to be a leading force in metallomics, the Journal must expand its horizons beyond traditional analytical spectroscopy per se. Accordingly, in this special issue you will find papers that have a heavy clinical emphasis, which speak to complementary (non-atomic) spectroscopic techniques, and that provide

  17. Genetics, realized heritability and preliminary mechanism of spinosad resistance in Phenacoccus solenopsis Tinsley (Homoptera: Pseudococcidae): an invasive pest from Pakistan.

    PubMed

    Afzal, Muhammad Babar Shahzad; Shad, Sarfraz Ali; Abbas, Naeem

    2015-12-01

    The cotton mealybug, Phenacoccus solenopsis Tinsley (Homoptera: Pseudococcidae) has gained recognition as a key pest due to its invasive nature throughout the world. The P. solenopsis has a wide range of host plants and damages the cotton crop in various parts of the world. In view of the economic importance of this pest, a study on selection, inheritance and mechanism of spinosad resistance was conducted on P. solenopsis. Selection of field collected P. solenopsis for seven generations with spinosad resulted in a high resistance ratio of 282.45-fold. Genetic studies of spinosad resistance in P. solenopsis indicated that maternal effects are not involved in spinosad resistance; and resistance development is an autosomal and incompletely dominant trait. The number of genes involved in spinosad resistance was determined to be more than one, suggesting that resistance is controlled by multiple loci. The realized heritability (h (2)) value for spinosad resistance was 0.94. Synergism bioassays of spinosad with piperonyl butoxide and S,S,S-tributyl phosphorotrithioate showed that spinosad resistance in P. solenopsis could be due to esterase only. The study provides the basic information for implementation of effective resistance management strategies to control P. solenopsis.

  18. Genetics, realized heritability and preliminary mechanism of spinosad resistance in Phenacoccus solenopsis Tinsley (Homoptera: Pseudococcidae): an invasive pest from Pakistan.

    PubMed

    Afzal, Muhammad Babar Shahzad; Shad, Sarfraz Ali; Abbas, Naeem

    2015-12-01

    The cotton mealybug, Phenacoccus solenopsis Tinsley (Homoptera: Pseudococcidae) has gained recognition as a key pest due to its invasive nature throughout the world. The P. solenopsis has a wide range of host plants and damages the cotton crop in various parts of the world. In view of the economic importance of this pest, a study on selection, inheritance and mechanism of spinosad resistance was conducted on P. solenopsis. Selection of field collected P. solenopsis for seven generations with spinosad resulted in a high resistance ratio of 282.45-fold. Genetic studies of spinosad resistance in P. solenopsis indicated that maternal effects are not involved in spinosad resistance; and resistance development is an autosomal and incompletely dominant trait. The number of genes involved in spinosad resistance was determined to be more than one, suggesting that resistance is controlled by multiple loci. The realized heritability (h (2)) value for spinosad resistance was 0.94. Synergism bioassays of spinosad with piperonyl butoxide and S,S,S-tributyl phosphorotrithioate showed that spinosad resistance in P. solenopsis could be due to esterase only. The study provides the basic information for implementation of effective resistance management strategies to control P. solenopsis. PMID:26494239

  19. [Advances in the biosynthesis of spinosad - A review].

    PubMed

    Sheng, Zhi; Chen, Kai; Li, Xu

    2016-03-01

    Spinosad, extracted from Saccharopolyspora spinosa, one of the most successful commercial bio-insecticides, is derived from a family of macrocyclic lactones. It shows excellent potent insecticidal activities, low residue, and low environmental effect. Here, we reviewed the biosynthetic pathway of spinosad, the chemoenzymatic method of spinosad synthesis, and the strain improvement method and the heterologous expression of spinosad. PMID:27382783

  20. Development of resistance to spinosad in oriental fruit fly (Diptera: Tephritidae) in laboratory selection and cross-resistance.

    PubMed

    Hsu, Ju-Chun; Feng, Hai-Tung

    2006-06-01

    In this study, we assessed the potential for the development of resistance to the insecticide spinosad in a laboratory colony of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). Resistance was selected by using topical applications of spinosad. After eight generations of selection, the LD50 of the selected line was 408 times greater compared with that of the untreated parental colony. This spinosad-resistant line did not exhibit cross-resistance to 10 other insecticides tested, including six organophosphates (naled, trichlorfon, fenitrothion. fenthion, formothion, and malathion) one carbamate (methomyl), and three pyrethroids (cyfluthrin, cypermethrin, and fenvalerate). However, using lines previously selected for resistance to these same insecticides, two of the 10 lines tested (naled- and malathion-resistant) did show some cross-resistance to spinosad. Also, oriental fruit flies from different field collections where naled and malathion have been used for control purposes displayed some resistance to spinosad. In addition, the effects of direct ingestion of spinosad through dietary supplementation also were tested. Overall, the laboratory resistance and cross-resistance data developed in this study provide new information that will be useful for managing the development of resistance when spinosad is used to control B. dorsalis in the field. PMID:16813333

  1. Topology of Coronal Fields from Evolving Magnetofrictional Models

    NASA Astrophysics Data System (ADS)

    DeRosa, Marc L.; Cheung, M.

    2012-05-01

    The evolving magnetofrictional (MF) scheme enables the construction of time-dependent models of the active region coronal magnetic field in response to photospheric driving. When advancing such models, only the magnetic induction is solved, during which the velocity at each point is assumed to be oriented parallel to the Lorentz force. This leads to the field to evolve toward a force-free state. We present results from an evolving MF model of NOAA AR11158 using driving from time sequences of SDO/HMI data. Utilizing this simulation, we investigate changes in magnetic configurations and topology, including the number of null points, evolution of quasi-separatrix layers, and the time-history of total and free magnetic energies as well as relative helicity. This work seeks to elucidate the relation(s) between topological and energetic properties of the AR.

  2. The effects of spinosad, a naturally derived insect control agent, to the honeybee (Apis melifera).

    PubMed

    Miles, M; Mayes, M; Dutton, R

    2002-01-01

    Spinosad is a novel insect control agent derived by fermentation of the Actinomycete bacterium, Saccharopolyspora spinosa. Spinosad controls many caterpillar pests in vines, pome fruit and vegetables (including tomatoes and peppers), thrips in tomatoes, peppers and ornamental cultivation and dipterous leafminers in vegetables and ornamentals. Application rates vary between 25 to 100 g of active substance per hectare (g as/ha) and 4.8 to 36 g of active substance per hectolitre (g as/hL) depending on the crop and target pest. It is important that plant protection products are authorized for use only in ways that do not pose an unacceptable risk of harm to honeybees. For this purpose testing was performed to enable the safety of spinosad to be evaluated. The effects of spinosad to honeybees have been extensively researched. Testing has been performed under a variety of conditions in a range of countries globally. Studies to determine the acute toxicity of spinosad under laboratory conditions were conducted to generate LD50 or LC50 values for oral and contact routes of administration. These demonstrated that spinosad was highly toxic to worker honeybees under worst case laboratory conditions and that the oral route of exposure provided the greater risk. Residue tests conducted under laboratory, semi-field and field conditions on worker honeybees foraging on treated foliage indicated that dry product residues were harmless. Therefore the effects seen in the laboratory acute toxicity tests did not translate to a more realistic exposure scenario indicating that safe use patterns for the product can be developed. Semi-field cage studies have also demonstrated that spinosad was safe to bees when applied to flowering crops during periods of bee activity. The majority of studies conducted have indicated that spinosad does not adversely affect honeybee behaviour, brood or queen. It can be concluded that spinosad when used according to the approved product label recommendations

  3. Field trials of spinosad as a replacement for naled, DDVP, and malathion in methyl eugenol and cue-lure bucket traps to attract and kill male oriental fruit flies and melon flies (Diptera: Tephritidae) in Hawaii.

    PubMed

    Vargas, Roger I; Miller, Neil W; Stark, John D

    2003-12-01

    Spinosad was evaluated in Hawaii as a replacement for organophosphate insecticides (naled, dichlorvos [DDVP], and malathion) in methyl eugenol and cue-lure bucket traps to attract and kill oriental fruit fly, Bactrocera dorsalis Hendel, and melon fly, B. cucurbitae Coquillett, respectively. In the first and second methyl eugenol trials with B. dorsalis, naled was in the highest rated group for all evaluation periods (at 5, 10, 15, and 20 wk). Spinosad was equal to naled at 5 and 10 wk during both trials 1 and 2, and compared favorably with malathion during trial 2. During the first cue-lure trial with B. cucurbitae, naled and malathion were in the top rated group at 5, 10, 15, and 20 wk. Spinosad was equal to naled at 5 wk. During the second cue-lure trial, spinosad and naled were both in the top rated group at 10, 15, and 20 wk. Use of male lure traps with methyl eugenol or cue-lure had no effect on attraction of females into test areas. Our results suggest that spinosad, although not as persistent as naled or malathion, is safer to handle and a more environmentally friendly substitute for organophosphate insecticides in methyl eugenol and cue-lure traps for use in B. dorsalis and B. cucurbitae areawide integrated pest management programs in Hawaii. PMID:14977115

  4. The magnetic field of the evolved star W43A

    NASA Astrophysics Data System (ADS)

    Amiri, N.; Vlemmings, W.; van Langevelde, H. J.

    2010-01-01

    Context. The majority of the observed planetary nebulae exhibit elliptical or bipolar structures. Recent observations have shown that asymmetries already start during the last stages of the AGB phase. Theoretical modeling has indicated that magnetically collimated jets may be responsible for the formation of the non-spherical planetary nebulae. Direct measurement of the magnetic field of evolved stars is possible using polarization observations of different maser species occurring in the circumstellar envelopes around these stars. Aims: The aim of this project is to measure the Zeeman splitting caused by the magnetic field in the OH and H2O maser regions occurring in the circumstellar envelope and bipolar outflow of the evolved star W43A. We compare the magnetic field obtained in the OH maser region with the one measured in the H2O maser jet. Methods: We used the UK Multi-Element Radio Linked Interferometer Network (MERLIN) to observe the polarization of the OH masers in the circumstellar envelope of W43A. Likewise, we used the Green Bank Telescope (GBT) observations to measure the magnetic field strength obtained previously in the H2O maser jet. Results: We report a measured magnetic field of approximately 100 μ G in the OH maser region of the circumstellar envelope around W43A. The GBT observations reveal a magnetic field strength B_|| of ~30 mG changing sign across the H2O masers at the tip of the red-shifted lobe of the bipolar outflow. We also find that the OH maser shell shows no sign of non-spherical expansion and that it probably has an expansion velocity that is typical for the shells of regular OH/IR stars. Conclusions: The GBT observations confirm that the magnetic field collimates the H2O maser jet, while the OH maser observations show that a strong large-scale magnetic field is present in the envelope surrounding the W43A central star. The magnetic field in the OH maser envelope is consistent with the one extrapolated from the H2O measurements

  5. In vivo functional analysis of the Drosophila melanogaster nicotinic acetylcholine receptor Dα6 using the insecticide spinosad.

    PubMed

    Somers, Jason; Nguyen, Joseph; Lumb, Chris; Batterham, Phil; Perry, Trent

    2015-09-01

    The vinegar fly, Drosophila melanogaster, has been used to identify and manipulate insecticide resistance genes. The advancement of genome engineering technology and the increasing availability of pest genome sequences has increased the predictive and diagnostic capacity of the Drosophila model. The Drosophila model can be extended to investigate the basic biology of the interaction between insecticides and the proteins they target. Recently we have developed an in vivo system that permits the expression and study of key insecticide targets, the nicotinic acetylcholine receptors (nAChRs), in controlled genetic backgrounds. Here this system is used to study the interaction between the insecticide spinosad and a nAChR subunit, Dα6. Reciprocal chimeric subunits were created from Dα6 and Dα7, a subunit that does not respond to spinosad. Using the in vivo system, the Dα6/Dα7 chimeric subunits were tested for their capacity to respond to spinosad. Only the subunits containing the C-terminal region of Dα6 were able to respond to spinosad, thus confirming the importance this region for spinosad binding. A new incompletely dominant, spinosad resistance mechanism that may evolve in pest species is also examined. First generated using chemical mutagenesis, the Dα6(P146S) mutation was recreated using the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 system, the first use of this technology to introduce a resistant mutation into a controlled genetic background. Both alleles present with the same incompletely dominant, spinosad resistance phenotype, proving the P146S replacement to be the causal mutation. The proximity of the P146S mutation to the conserved Cys-loop indicates that it may impair the gating of the receptor. The results of this study enhance the understanding of nAChR structure:function relationships. PMID:25747007

  6. In vivo functional analysis of the Drosophila melanogaster nicotinic acetylcholine receptor Dα6 using the insecticide spinosad.

    PubMed

    Somers, Jason; Nguyen, Joseph; Lumb, Chris; Batterham, Phil; Perry, Trent

    2015-09-01

    The vinegar fly, Drosophila melanogaster, has been used to identify and manipulate insecticide resistance genes. The advancement of genome engineering technology and the increasing availability of pest genome sequences has increased the predictive and diagnostic capacity of the Drosophila model. The Drosophila model can be extended to investigate the basic biology of the interaction between insecticides and the proteins they target. Recently we have developed an in vivo system that permits the expression and study of key insecticide targets, the nicotinic acetylcholine receptors (nAChRs), in controlled genetic backgrounds. Here this system is used to study the interaction between the insecticide spinosad and a nAChR subunit, Dα6. Reciprocal chimeric subunits were created from Dα6 and Dα7, a subunit that does not respond to spinosad. Using the in vivo system, the Dα6/Dα7 chimeric subunits were tested for their capacity to respond to spinosad. Only the subunits containing the C-terminal region of Dα6 were able to respond to spinosad, thus confirming the importance this region for spinosad binding. A new incompletely dominant, spinosad resistance mechanism that may evolve in pest species is also examined. First generated using chemical mutagenesis, the Dα6(P146S) mutation was recreated using the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 system, the first use of this technology to introduce a resistant mutation into a controlled genetic background. Both alleles present with the same incompletely dominant, spinosad resistance phenotype, proving the P146S replacement to be the causal mutation. The proximity of the P146S mutation to the conserved Cys-loop indicates that it may impair the gating of the receptor. The results of this study enhance the understanding of nAChR structure:function relationships.

  7. Response of melon fly (Diptera: Tephritidae) to weathered SPLAT-Spinosad-Cue-Lure.

    PubMed

    Vargas, Roger I; Piñero, Jaime C; Jang, Eric B; Mau, Ronald F L; Stark, John D; Gomez, Luis; Stoltman, Lyndsie; Mafra-Neto, Agenor

    2010-10-01

    Studies were conducted in Hawaii to measure attraction of male melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), to SPLAT-Cue-Lure (C-L) and SPLAT-Melo-Lure (M-L) (raspberry ketone formate). Direct field comparisons of SPLAT-C-L and SPLAT-M-L at low (5%) and high (20%) concentrations indicated few differences in attraction over a 15-wk period. Subsequently, only SPLAT-Spinosad-C-L (5%) was compared with Min-U-Gel C-L with naled (standard used in California) in weathering studies. Treatments were weathered for 1, 2, 4, and 8 wk in Riverside, CA, and shipped to Hawaii for attraction/toxicity tests under field and semifield conditions by using released males of controlled ages, and for feeding tests in the laboratory. In terms of attraction, SPLAT-Spinosad-C-L compared favorably to, or outperformed the current standard of Min-U-Gel-C-L with naled. In terms of toxicity, the cumulative 24-h mortality did not differ between the two insecticide-containing C-L treatments in field cage studies after 8 wk. However, in feeding studies in which individual males were exposed for 5 min to the different C-L treatments after 4 wk of weathering, SPLAT-Spinosad-C-L demonstrated reduced mortality compared with the Min-U-Gel-C-L with naled, suggesting reduced persistence of the spinosad material. Spinosad has low contact toxicity and when mixed with SPLAT and C-L offers a reduced risk alternative for control of B. cucurbitae and related C-L-responding species, without many of the negative effects to humans and nontargets of broad-spectrum contact poisons such as naled. PMID:21061958

  8. The α6 nicotinic acetylcholine receptor subunit of Frankliniella occidentalis is not involved in resistance to spinosad.

    PubMed

    Hou, Wenjie; Liu, Qiulei; Tian, Lixia; Wu, Qingjun; Zhang, Youjun; Xie, Wen; Wang, Shaoli; Miguel, Keri San; Funderburk, Joe; Scott, Jeffrey G

    2014-05-01

    Insects evolve resistance which constrains the sustainable use of insecticides. Spinosyns, a class of environmentally-friendly macrolide insecticides, is not an exception. The mode of inheritance and the mechanisms of resistance to spinosad (the most common spinosyn insecticide) in Frankliniella occidentalis (Western flower thrips, WFT) were investigated in this study. Resistance (170,000-fold) was autosomal and completely recessive. Recent studies showed that deletion of the nicotinic acetylcholine receptor α6 subunit gene resulted in strains of Drosophila melanogaster, Plutella xylostella and Bactrocera dorsalis that are resistant to spinosad, indicating that nAChRα6 subunit maybe important for the toxic action of this insecticide. Conversely, a G275E mutation of this subunit in F. occidentalis was recently proposed as the mechanism of resistance to spinosad. We cloned and characterized nAChRα6 from three susceptible and two spinosad resistant strains from China and the USA. The Foα6 cDNA is 1873bp and the open reading frame is 1458bp which encodes 485 amino acid residues with a predicted molecular weight of 53.5-kDa, the 5' and 3' UTRs are 121 and 294bp, respectively. There was no difference in the cDNA sequence between the resistant and susceptible thrips, suggesting the G275E mutation does not confer resistance in these populations. Ten isoforms of Foα6, arising from alternative splicing, were isolated and did not differ between the spinosad-susceptible and resistant strains. Quantitative real time PCR analysis showed Foα6 was highly expressed in the first instar larva, pupa and adult, and the expression levels were 3.67, 2.47, 1.38 times that of the second instar larva. The expression level was not significantly different between the susceptible and resistant strains. These results indicate that Foα6 is not involved in resistance to spinosad in F. occidentalis from China and the USA. PMID:24861935

  9. The α6 nicotinic acetylcholine receptor subunit of Frankliniella occidentalis is not involved in resistance to spinosad.

    PubMed

    Hou, Wenjie; Liu, Qiulei; Tian, Lixia; Wu, Qingjun; Zhang, Youjun; Xie, Wen; Wang, Shaoli; Miguel, Keri San; Funderburk, Joe; Scott, Jeffrey G

    2014-05-01

    Insects evolve resistance which constrains the sustainable use of insecticides. Spinosyns, a class of environmentally-friendly macrolide insecticides, is not an exception. The mode of inheritance and the mechanisms of resistance to spinosad (the most common spinosyn insecticide) in Frankliniella occidentalis (Western flower thrips, WFT) were investigated in this study. Resistance (170,000-fold) was autosomal and completely recessive. Recent studies showed that deletion of the nicotinic acetylcholine receptor α6 subunit gene resulted in strains of Drosophila melanogaster, Plutella xylostella and Bactrocera dorsalis that are resistant to spinosad, indicating that nAChRα6 subunit maybe important for the toxic action of this insecticide. Conversely, a G275E mutation of this subunit in F. occidentalis was recently proposed as the mechanism of resistance to spinosad. We cloned and characterized nAChRα6 from three susceptible and two spinosad resistant strains from China and the USA. The Foα6 cDNA is 1873bp and the open reading frame is 1458bp which encodes 485 amino acid residues with a predicted molecular weight of 53.5-kDa, the 5' and 3' UTRs are 121 and 294bp, respectively. There was no difference in the cDNA sequence between the resistant and susceptible thrips, suggesting the G275E mutation does not confer resistance in these populations. Ten isoforms of Foα6, arising from alternative splicing, were isolated and did not differ between the spinosad-susceptible and resistant strains. Quantitative real time PCR analysis showed Foα6 was highly expressed in the first instar larva, pupa and adult, and the expression levels were 3.67, 2.47, 1.38 times that of the second instar larva. The expression level was not significantly different between the susceptible and resistant strains. These results indicate that Foα6 is not involved in resistance to spinosad in F. occidentalis from China and the USA.

  10. LIDAR Wind Speed Measurements of Evolving Wind Fields

    SciTech Connect

    Simley, E.; Pao, L. Y.; Kelley, N.; Jonkman, B.; Frehlich, R.

    2012-01-01

    is the spatial averaging caused by the LIDAR's sampling volume. However, by introducing wind evolution, the dominant source of error for large preview distances was found to be the coherence loss caused by evolving turbulence. Different measurement geometries were compared using the bandwidth for which the measurement coherence remained above 0.5 and also the area under the measurement coherence curve. Results showed that, by increasing the intensity of wind evolution, the measurement coherence decreases. Using the coherence bandwidth metric, the optimal preview distance for a fixed-scan radius remained almost constant for low and moderate amounts of wind evolution. For the wind field with the simple wind evolution model introduced, the optimal preview distance for a scan radius of 75% blade span (47.25 meters) was found to be 80 meters. Using the LES wind field, the optimal preview distance was 65 meters. When comparing scan geometries using the area under the coherence curve, results showed that, as the intensity of wind evolution increases, the optimal preview distance decreases.

  11. Evaluation of SPLAT with spinosad and methyl eugenol or cue-lure for "attract-and-kill" of oriental and melon fruit flies (Diptera: Tephritidae) in Hawaii.

    PubMed

    Vargas, Roger I; Stark, John D; Hertlein, Mark; Neto, Agenor Mafra; Coler, Reginald; Piñero, Jaime C

    2008-06-01

    Specialized Pheromone and Lure Application Technology (SPLAT) methyl eugenol (ME) and cue-lure (C-L) "attract-and-kill" sprayable formulations containing spinosad were compared with other formulations under Hawaiian weather conditions against oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), respectively. Field tests were conducted with three different dispensers (Min-U-Gel, Acti-Gel, and SPLAT) and two different insecticides (naled and spinosad). SPLAT ME with spinosad was equal in performance to the standard Min-U-Gel ME with naled formulation up to 12 wk. SPLAT C-L with spinosad was equal in performance to the standard Min-U-Gel C-L with naled formulation during weeks 7 to12, but not during weeks 1-6. In subsequent comparative trials, SPLAT ME + spinosad compared favorably with the current standard of Min-U-Gel ME + naled for up to 6 wk, and it was superior from weeks 7 to 12 in two separate tests conducted in a papaya (Carica papaya L.) orchard and a guava (Psidium guajava L.) orchard, respectively. In outdoor paired weathering tests (fresh versus weathered), C-L dispensers (SPLAT + spinosad, SPLAT + naled, and Min-U-Gel + naled) were effective up to 70 d. Weathered ME dispensers with SPLAT + spinosad compared favorably with SPLAT + naled and Min-U-Gel + naled, and they were equal to fresh dispensers for 21-28 d, depending on location. Our current studies indicate that SPLAT ME and SPLAT C-L sprayable attract-and-kill dispensers containing spinosad are a promising substitute for current liquid organophosphate insecticide formulations used for areawide suppression of B. dorsalis and B. cucurbitae in Hawaii. PMID:18613576

  12. Comparison of aeration and spinosad for suppressing insects in stored wheat.

    PubMed

    Flinn, P W; Subramanyam, Bh; Arthur, F H

    2004-08-01

    Field studies were conducted from July 2002 to January 2003 for evaluating the effects of controlled aeration and a commercial biological insecticide, spinosad, in suppressing insect populations in stored wheat. Six cylindrical steel bins were filled with newly harvested (2002 crop year) hard red winter wheat on 9 and 10 July 2002. Each bin contained 30.7 metric tons (1,100 bu) of wheat. Wheat in two bins was left untreated (control), whereas wheat in two bins was treated with spinosad, and in another two bins was subjected to aeration by using aeration controllers. Spinosad was applied to wheat at the time of bin filling to obtain a rate of 1 mg ([AI])/kg. Aeration controllers were set to run the fans when ambient air temperature fell below 23.9, 18.3, and 7.2 degrees C for the first, second, and third cooling cycles, respectively. We added 400 adults each of the rusty grain beetle, Cryptolestes ferrugineus (Stephens); lesser grain borer, Rhyzopertha dominica (F.); and red flour beetle, Tribolium castaneum (Herbst), to the grain at monthly intervals between July and October 2002. Insect density in the bins was estimated monthly by taking 3-kg grain samples from 21 locations within each bin by using a pneumatic grain sampler. No live T. castaneum or C. ferrugineus and very low densities of R. dominica (<0.008 adults per kilogram) were found in wheat treated with spinosad during the 6-mo sampling period. Density of C. ferrugineus and T. castaneum in aerated bins did not exceed two adults per kilogram (the Federal Grain Inspection Service standard for infested wheat), whereas R. dominica increased to 12 adults per kilogram in November 2002, which subsequently decreased to three adults per kilogram in January 2003. In the untreated (control) bins, R. dominica density increased faster than that of C. ferrugineus or T. castaneum. Density of R. dominica peaked at 58 adults per kilogram in October 2002 and decreased subsequently, whereas T. castaneum density was 10 adults

  13. Coming of Age: The Evolving Field of Adventure Therapy

    ERIC Educational Resources Information Center

    Bandoroff, Scott, Ed.; Newes, Sandra, Ed.

    2006-01-01

    "Coming of Age" brings together a group of articles arising from the third International Adventure Therapy Conference held in Victoria, British Columbia, in April 2003. Together, they offer an overview of the field of Adventure Therapy in the new millennium, boasting a strong collection from the field's leading international figures: Martin…

  14. In vitro and in vivo acaricidal activity and residual toxicity of spinosad to the poultry red mite, Dermanyssus gallinae.

    PubMed

    George, D R; Shiel, R S; Appleby, W G C; Knox, A; Guy, J H

    2010-10-29

    This paper describes two experiments conducted to examine the acaricidal potential of spinosad against the poultry red mite, Dermanyssus gallinae (De Geer), a serious ectoparasitic pest of laying hens. Spinosad is a natural product derived from the fermentation of the micro-organism Saccharopolyspora spinosa. In vitro testing confirmed that, when applied to a galvanised metal plate to the point of run-off, spinosad was toxic to adult female D. gallinae and suggested that at an application rate of 3.88 g/L a significant residual toxicity of spinosad could be achieved for up to 21 days. A subsequent in vivo experiment in a conventional cage housing system for laying hens demonstrated the acaricidal activity and residual toxicity to D. gallinae of a single application of spinosad when applied at either 1.94 or 3.88 g/L. Residual toxicity of spinosad at both of these application rates was maintained throughout the course of the 28 day post-spray study period, with a peak in product efficacy seen 14 days after spraying. The results suggest that the greater the D. gallinae population the greater will be the toxic effect of spinosad. Although the exact reasons for this are unclear, it can be speculated that conspecifics spread the product between each other more efficiently at higher mite population densities. However, further study is warranted to confirm this possibility. Application of spinosad in vivo had no effect on hen bodyweight or egg production parameters (number and weight), suggesting that this product could be used to effectively control D. gallinae infestations whilst birds are in lay. This paper also describes a novel method for effectively and efficiently achieving replication of treatments in a single poultry house, previously unpopulated with D. gallinae. Individual groups of conventional cages were stocked with hens, seeded with D. gallinae and used as replicates. Independence of replicates was achieved by isolating cage groups from one another using a

  15. Field Evolved Resistance in Helicoverpa armigera (Lepidoptera: Noctuidae) to Bacillus thuringiensis Toxin Cry1Ac in Pakistan

    PubMed Central

    Alvi, Anwaar H. K.; Sayyed, Ali H.; Naeem, Muhammad; Ali, Muhammad

    2012-01-01

    Helicoverpa armigera (Hübner) is one of the most destructive pests of several field and vegetable crops, with indiscriminate use of insecticides contributing to multiple instances of resistance. In the present study we assessed whether H. armigera had developed resistance to Bt cotton and compared the results with several conventional insecticides. Furthermore, the genetics of resistance was also investigated to determine the inheritance to Cry1Ac resistance. To investigate the development of resistance to Bt cotton, and selected foliar insecticides, H. armigera populations were sampled in 2010 and 2011 in several cotton production regions in Pakistan. The resistance ratios (RR) for Cry1Ac, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin and deltamethrin were 580-fold, 320-, 1110-, 1950-, 200-, 380, 690, and 40-fold, respectively, compared with the laboratory susceptible (Lab-PK) population. Selection of the field collected population with Cry1Ac in 2010 for five generations increased RR to 5440-fold. The selection also increased RR for deltamethrin, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin to 125-folds, 650-, 2840-, 9830-, 370-, 3090-, 1330-fold. The estimated LC50s for reciprocal crosses were 105 µg/ml (Cry1Ac-SEL female × Lab-PK male) and 81 g µg/ml (Lab-PK female × Cry1Ac-SEL male) suggesting that the resistance to Cry1Ac was autosomal; the degree of dominance (DLC) was 0.60 and 0.57 respectively. Mixing of enzyme inhibitors significantly decreased resistance to Cry1Ac suggesting that the resistance to Cry1Ac and other insecticides tested in the present study was primarily metabolic. Resistance to Cry1Ac was probably due to a single but unstable factor suggesting that crop rotation with non-Bt cotton or other crops could reduce the selection pressure for H. armigera and improve the sustainability of Bt cotton. PMID:23077589

  16. Toxicological assessment of spinosad: Implications for integrated control of Aedes aegypti using larvicides and larvivorous fish.

    PubMed

    Pereira, Boscolli Barbosa; Caixeta, Evelyn Siqueira; Freitas, Priscila Costa; Santos, Vanessa Santana Vieira; Limongi, Jean Ezequiel; de Campos Júnior, Edimar Olegário; Campos, Carlos Fernando; Souto, Henrique Nazareth; Rodrigues, Tamiris Sabrina; Morelli, Sandra

    2016-01-01

    Integration of larvivorous fish and biolarvicides at low concentrations to control of mosquito larvae in field situations may result in a safer and more effective tool. However, the usefulness of integrated approach depends upon survival and ecological fitness of fish employed. Thus, the aim of this study was to examine the genotoxic effects of combining different sublethal concentrations of spinosad, a naturally occurring neurotoxic insecticide, with male adult poecilid larvivorous guppy (Poecilia reticulata) and platy (Xiphophorus maculatus) fish on Aedes larvae mosquitos. Both fish species have been used for biological control of Aedes larvae in Brazil. Sublethal spinosad exposures were predetermined based on CL50-96hr. Nuclear abnormalities (NA) and micronucleus (MN) frequency in gill cells were measured after 14 d of exposure. Behavioral changes were monitored over 96 h. Although genotoxic effects were not markedly different from control, behavioral changes evaluated based upon the no-observable-effect concentration (NOEC) and lowest-observable-effect concentration (LOEC). Adverse effects were noted at concentrations of 12.6 mg/L (NOEC) and 25.3 mg/L (LOEC) spinosad. Therefore, these insecticide concentrations may be considered as being safe to these fish species and have important implications for integrated approach to control Aedes larvae using natural larvicides and larvivorous fish. PMID:27294296

  17. LIDAR Wind Speed Measurements of Evolving Wind Fields

    SciTech Connect

    Simley, E.; Pao, L. Y.

    2012-07-01

    Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed Taylor's frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations to create a more realistic measurement model. A simple model of wind evolution is applied to a frozen wind field used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements are also evaluated with a large eddy simulation of a stable boundary layer provided by the National Center for Atmospheric Research. Simulation results show the combined effects of LIDAR errors and wind evolution for realistic turbine-mounted LIDAR measurement scenarios.

  18. Planetary Nebulae: Reviews and Previews of a Rapidly Evolving Field

    NASA Astrophysics Data System (ADS)

    Balick, Bruce

    2015-01-01

    Observational results from the ground and space in the past decade and covering the entire spectrum have jolted and energized research into the nature, the formation, and the evolution of planetary nebulae (PNs). The 101-level bubble structure of PNs turned out to be a pleasant but misleading fantasy as observations by HST and ALMA revealed basic details of their infancy. Some combination of close geriatric binary stars (the precusrors of SN Ia's) and magnetic fields dredged into the dusty winds appear to play vital roles in the ejection and collimation of AGB atmospheres. As a result, PNe and their antecedents, AGB stars and prePNs, are providing an array of new opportunities to study asymmetric wind formation, complex gas dynamics, CNO production rates in various galactic environments, and galaxy structure and evolution. I shall review the highlights of recent results, summarize their interpretations, and show some of the observational opportunities to monitor in the next decade, many of which couple strongly to research to related fields.This talk is dedicated to the career of Olivier Chesneau (1972-2014) who pioneered new high-resolution imaging methods that peered into the deep inner cores of nascent planetary nebulae. We remember Olivier as everyone's enthusiastic friend and colleague whose career ended in full stride.

  19. Evolving test fields in a black-hole geometry

    NASA Astrophysics Data System (ADS)

    Andersson, Nils

    1997-01-01

    We consider the initial value problem for a massless scalar field in the Schwarzschild geometry. When constructed using a complex-frequency approach the necessary Green's function splits into three components. We discuss all of these in some detail. (1) The contribution from the singularities (the quasinormal modes of the black hole) is approximated and the mode sum is demonstrated to converge after a certain well-defined time in the evolution. A dynamic description of the mode excitation is introduced and tested. (2) It is shown how a straightforward low-frequency approximation to the integral along the branch cut in the black-hole Green's function leads to the anticipated power-law falloff at very late times. We also calculate higher order corrections to this tail and show that they provide an important complement to the leading order. (3) The high-frequency problem is also considered. We demonstrate that the combination of the obtained approximations for the quasinormal modes and the power-law tail provide a complete description of the evolution at late times. Problems that arise (in the complex-frequency picture) for early times are also discussed, as is the fact that many of the presented results generalize to, for example, Kerr black holes.

  20. Efficacy and non-target impact of spinosad, Bti and temephos larvicides for control of Anopheles spp. in an endemic malaria region of southern Mexico

    PubMed Central

    2014-01-01

    Background The larvicidal efficacy of the naturally derived insecticide spinosad, for control of immature stages of Anopheles albimanus and associated culicids, was compared to that of synthetic and biological larvicides. Effects on non-target insects were also determined. Methods A field trial was performed in replicated temporary pools during the rainy season, in southern Mexico. Pools were treated with 10 ppm a.i. spinosad (Tracer 480SC), Bti granules applied at 2 kg/ha (VectoBac WDG, ABG-6511), and 100 ml/ha temephos (50 EC), or an untreated control. Numbers of immature mosquitoes, and aquatic insects in pools were monitored for 20 weeks. Results Samples of immature mosquitoes comprised approximately 10% An. albimanus, 70% Culex spp. (mostly Cx. melanoconion and Cx. coronator) and 20% Uranotaenia lowii. The most effective larvicides were spinosad and temephos that eliminated An. albimanus in 16 out of 20 post-treatment samples, or 9 weeks of continuous control of immature stages, respectively. These larvicides resulted in 15 and 5 weeks of elimination of Culex spp., respectively, or 20 and 4 weeks of continuous elimination of U. lowii, respectively. Bti treatment provided little consistent control. Aquatic insects were recorded comprising 3 orders, 20 families, 40 genera and 44 species. Shannon diversity index values (H’) for aquatic insects were highest in the control (0.997) and Bti (0.974) treatments, intermediate in the spinosad treatment (0.638) and lowest in the temephos treatment (0.520). Severely affected non-target insects in the spinosad and temephos treated pools were predatory Coleoptera, Hemiptera and Odonata, which in the case of spinosad was likely due to the high concentration applied. Bti had little effect on aquatic insects. Conclusions The spinosad treatment retained larvicidal activity for markedly longer than expected. Spinosad is likely to be an effective tool for control of anopheline and other pool-breeding mosquitoes in tropical

  1. Field-evolved resistance: assessing the problem and ways to move forward.

    PubMed

    Sumerford, Douglas V; Head, Graham P; Shelton, Anthony; Greenplate, John; Moar, William

    2013-08-01

    "Field-evolved resistance" is defined as a "genetically based decrease in susceptibility of a population to a toxin caused by exposure to the toxin in the field." The key component of "field-evolved" resistance is that it does confer decreased susceptibility to an insecticide in the field. Another key component is that the decrease in susceptibility to the insecticide is because of previous exposure of the target insect to the toxin in the field. Several studies have reported field-evolved resistance to crops engineered to express proteins from the bacterium, Bacillus thuringiensis (Bt). However, there has not been a consistent standard in the application of the definition of field-evolved resistance for Bt crops. The inconsistency in applying the definition arises from differences in the methods used to detect resistance, the ecology of the interaction between the pest and the Bt crop, and the effective dose the pest encounters while feeding on the Bt crop. Using case studies of reported resistance to Bt crops, it is demonstrated resistance does not come in a single form, and that in most cases, resistance can still be managed.

  2. A New Medium for Improving Spinosad Production by Saccharopolyspora spinosa

    PubMed Central

    Guojun, Yang; Yuping, He; Yan, Jiang; Kaichun, Lin; Haiyang, Xia

    2016-01-01

    Background Spinosad (a mixture of spinosyns A and D) is a unique natural pesticide produced by Saccharopolyspora spinosa. With regard to attempts to improve S. spinosa by classical mutagenesis, we propose that the bottleneck of screening out high-spinosad-production strains is probably caused by the fermentation media. Objectives The current study aimed to identify a new medium to extensively investigate the potential of S. spinosa strains to produce spinosad. Materials and Methods Statistical and regressive modeling methods were used to investigate the effects of the carbon source and to optimize the production media. Results The spinosad production of S. spinosa Co121 increased 77.13%, from 310.44 ± 21.84 μg/mL in the initial fermentation medium (with glucose as the main carbon source) to 549.89 ± 38.59 μg/mL in a new optimized fermentation medium (98.0 g of mannitol, 43.0 g of cottonseed flour, 12.9 g of corn steep liquor, 0.5 g of KH2PO4, and 3.0 g of CaCO3 in 1 L of H2O; pH was adjusted to 7.0 before autoclaving). After screening 4,000 strains, an overall 3.33-fold increase was observed in spinosad titers, starting from the parental strain Co121 in the original fermentation medium and ending with the mutant strain J78 (1035 ± 34 μg/mL) in the optimized medium. Conclusions The optimized fermentation medium developed in this study can probably be used to improve spinosad production in screening industrial strains of S. spinosa. PMID:27635207

  3. A New Medium for Improving Spinosad Production by Saccharopolyspora spinosa

    PubMed Central

    Guojun, Yang; Yuping, He; Yan, Jiang; Kaichun, Lin; Haiyang, Xia

    2016-01-01

    Background Spinosad (a mixture of spinosyns A and D) is a unique natural pesticide produced by Saccharopolyspora spinosa. With regard to attempts to improve S. spinosa by classical mutagenesis, we propose that the bottleneck of screening out high-spinosad-production strains is probably caused by the fermentation media. Objectives The current study aimed to identify a new medium to extensively investigate the potential of S. spinosa strains to produce spinosad. Materials and Methods Statistical and regressive modeling methods were used to investigate the effects of the carbon source and to optimize the production media. Results The spinosad production of S. spinosa Co121 increased 77.13%, from 310.44 ± 21.84 μg/mL in the initial fermentation medium (with glucose as the main carbon source) to 549.89 ± 38.59 μg/mL in a new optimized fermentation medium (98.0 g of mannitol, 43.0 g of cottonseed flour, 12.9 g of corn steep liquor, 0.5 g of KH2PO4, and 3.0 g of CaCO3 in 1 L of H2O; pH was adjusted to 7.0 before autoclaving). After screening 4,000 strains, an overall 3.33-fold increase was observed in spinosad titers, starting from the parental strain Co121 in the original fermentation medium and ending with the mutant strain J78 (1035 ± 34 μg/mL) in the optimized medium. Conclusions The optimized fermentation medium developed in this study can probably be used to improve spinosad production in screening industrial strains of S. spinosa.

  4. Field-evolved insect resistance to Bt crops: definition, theory, and data.

    PubMed

    Tabashnik, Bruce E; Van Rensburg, J B J; Carrière, Yves

    2009-12-01

    Transgenic crops producing Bacillus thuringiensis (Bt) toxins for insect pest control have been successful, but their efficacy is reduced when pests evolve resistance. Here we review the definition of field-evolved resistance, the relationship between resistance and field control problems, the theory underlying strategies for delaying resistance, and resistance monitoring methods. We also analyze resistance monitoring data from five continents reported in 41 studies that evaluate responses of field populations of 11 lepidopteran pests to four Bt toxins produced by Bt corn and cotton. After more than a decade since initial commercialization of Bt crops, most target pest populations remain susceptible, whereas field-evolved resistance has been documented in some populations of three noctuid moth species: Spodoptera frugiperda (J. E. Smith) to Cry1F in Bt corn in Puerto Rico, Busseola fusca (Fuller) to CrylAb in Bt corn in South Africa, and Helicoverpa zea (Boddie) to CrylAc and Cry2Ab in Bt cotton in the southeastern United States. Field outcomes are consistent with predictions from theory, suggesting that factors delaying resistance include recessive inheritance of resistance, abundant refuges of non-Bt host plants, and two-toxin Bt crops deployed separately from one-toxin Bt crops. The insights gained from systematic analyses of resistance monitoring data may help to enhance the durability of transgenic insecticidal crops. We recommend continued use of the longstanding definition of resistance cited here and encourage discussions about which regulatory actions, if any, should be triggered by specific data on the magnitude, distribution, and impact of field-evolved resistance.

  5. Field-evolved resistance to Bt maize by western corn rootworm: predictions from the laboratory and effects in the field.

    PubMed

    Gassmann, Aaron J

    2012-07-01

    Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) provide an effective management tool for many key insect pests. However, pest species have repeatedly demonstrated their ability to adapt to management practices. Results from laboratory selection experiments illustrate the capacity of pest species to evolve Bt resistance. Furthermore, resistance has been documented to Bt sprays in the field and greenhouse, and more recently, by some pests to Bt crops in the field. In 2009, fields were discovered in Iowa (USA) with populations of western corn rootworm, Diabrotica virgifera virgifera LeConte, that had evolved resistance to maize that produces the Bt toxin Cry3Bb1. Fields with resistant insects in 2009 had been planted to Cry3Bb1 maize for at least three consecutive years and as many as 6years. Computer simulation models predicted that the western corn rootworm might evolve resistance to Bt maize in as few as 3years. Laboratory and field data for interactions between western corn rootworm and Bt maize indicate that currently commercialized products are not high-dose events, which increases the risk of resistance evolution because non-recessive resistance traits may enhance survival on Bt maize. Furthermore, genetic analysis of laboratory strains of western corn rootworm has found non-recessive inheritance of resistance. Field studies conducted in two fields identified as harboring Cry3Bb1-resistant western corn rootworm found that survival of western corn rootworm did not differ between Cry3Bb1 maize and non-Bt maize and that root injury to Cry3Bb1 maize was higher than injury to other types of Bt maize or to maize roots protected with a soil insecticide. These first cases of field-evolved resistance to Bt maize by western corn rootworm provide an early warning and point to the need to apply better integrated pest management practices when using Bt maize to manage western corn rootworm.

  6. Transport equations for low-energy solar particles in evolving interplanetary magnetic fields

    NASA Technical Reports Server (NTRS)

    Ng, C. K.

    1988-01-01

    Two new forms of a simplified Fokker-Planck equation are derived for the transport of low-energy solar energetic particles in an evolving interplanetary magnetic field, carried by a variable radial solar wind. An idealized solution suggests that the 'invariant' anisotropy direction reported by Allum et al. (1974) may be explained within the conventional theoretical framework. The equations may be used to relate studies of solar particle propagation to solar wind transients, and vice versa.

  7. A mean-field analysis of the simple model of evolving open systems

    NASA Astrophysics Data System (ADS)

    Shimada, Takashi; Ogushi, Fumiko

    2016-09-01

    A recently reported mechanism of letting evolving systems grow only if the interactions in it is moderately sparse is reviewed and examined. It is shown that the mean field analysis, which is known to give a good simple understanding for this transition from growing to non-growing phase but with about 30% difference in its position, is well improved by taking only mean field type information from the simulation of the original model. This supports the validity of the understanding for the mechanism of the transition, obtained from the mean field analysis. The transition stems from an essential balance of two effects: although having more interactions makes each node robust, it also increases the impact of the loss of a node.

  8. Treatment of early-stage HER2+ breast cancer—an evolving field

    PubMed Central

    Ferreira, Arlindo R; Saini, Kamal S; Metzger-Filho, Otto

    2015-01-01

    The evolving field of HER2-targeted therapy has significantly improved the outcome of women diagnosed with HER2-positive invasive breast cancer. In this review, we sought to summarise the efficacy of trastuzumab-based regimens in the adjuvant and neoadjuvant setting with a special emphasis on relevant clinical questions: treatment duration, sequence of trastuzumab administration, toxicity, the role of anthracycline-based regimens, and optimal management of small HER2+ tumours. Controversial topics are discussed taking into consideration the development of modern anti-HER2 agents. PMID:25932047

  9. A CRISPR/Cas9 mediated point mutation in the alpha 6 subunit of the nicotinic acetylcholine receptor confers resistance to spinosad in Drosophila melanogaster.

    PubMed

    Zimmer, Christoph T; Garrood, William T; Puinean, A Mirel; Eckel-Zimmer, Manuela; Williamson, Martin S; Davies, T G Emyr; Bass, Chris

    2016-06-01

    Spinosad, a widely used and economically important insecticide, targets the nicotinic acetylcholine receptor (nAChRs) of the insect nervous system. Several studies have associated loss of function mutations in the insect nAChR α6 subunit with resistance to spinosad, and in the process identified this particular subunit as the specific target site. More recently a single non-synonymous point mutation, that does not result in loss of function, was identified in spinosad resistant strains of three insect species that results in an amino acid substitution (G275E) of the nAChR α6 subunit. The causal role of this mutation has been called into question as, to date, functional evidence proving its involvement in resistance has been limited to the study of vertebrate receptors. Here we use the CRISPR/Cas9 gene editing platform to introduce the G275E mutation into the nAChR α6 subunit of Drosophila melanogaster. Reverse transcriptase-PCR and sequencing confirmed the presence of the mutation in Dα6 transcripts of mutant flies and verified that it does not disrupt the normal splicing of the two exons in close vicinity to the mutation site. A marked decrease in sensitivity to spinosad (66-fold) was observed in flies with the mutation compared to flies of the same genetic background minus the mutation, clearly demonstrating the functional role of this amino acid substitution in resistance to spinosad. Although the resistance levels observed are 4.7-fold lower than exhibited by a fly strain with a null mutation of Dα6, they are nevertheless predicated to be sufficient to result in resistance to spinosad at recommended field rates. Reciprocal crossings with susceptible fly strains followed by spinosad bioassays revealed G275E is inherited as an incompletely recessive trait, thus resembling the mode of inheritance described for this mutation in the western flower thrips, Frankliniella occidentalis. This study both resolves a debate on the functional significance of a target

  10. A CRISPR/Cas9 mediated point mutation in the alpha 6 subunit of the nicotinic acetylcholine receptor confers resistance to spinosad in Drosophila melanogaster.

    PubMed

    Zimmer, Christoph T; Garrood, William T; Puinean, A Mirel; Eckel-Zimmer, Manuela; Williamson, Martin S; Davies, T G Emyr; Bass, Chris

    2016-06-01

    Spinosad, a widely used and economically important insecticide, targets the nicotinic acetylcholine receptor (nAChRs) of the insect nervous system. Several studies have associated loss of function mutations in the insect nAChR α6 subunit with resistance to spinosad, and in the process identified this particular subunit as the specific target site. More recently a single non-synonymous point mutation, that does not result in loss of function, was identified in spinosad resistant strains of three insect species that results in an amino acid substitution (G275E) of the nAChR α6 subunit. The causal role of this mutation has been called into question as, to date, functional evidence proving its involvement in resistance has been limited to the study of vertebrate receptors. Here we use the CRISPR/Cas9 gene editing platform to introduce the G275E mutation into the nAChR α6 subunit of Drosophila melanogaster. Reverse transcriptase-PCR and sequencing confirmed the presence of the mutation in Dα6 transcripts of mutant flies and verified that it does not disrupt the normal splicing of the two exons in close vicinity to the mutation site. A marked decrease in sensitivity to spinosad (66-fold) was observed in flies with the mutation compared to flies of the same genetic background minus the mutation, clearly demonstrating the functional role of this amino acid substitution in resistance to spinosad. Although the resistance levels observed are 4.7-fold lower than exhibited by a fly strain with a null mutation of Dα6, they are nevertheless predicated to be sufficient to result in resistance to spinosad at recommended field rates. Reciprocal crossings with susceptible fly strains followed by spinosad bioassays revealed G275E is inherited as an incompletely recessive trait, thus resembling the mode of inheritance described for this mutation in the western flower thrips, Frankliniella occidentalis. This study both resolves a debate on the functional significance of a target

  11. Attraction and mortality of Bactrocera dorsalis (Diptera: Tephritidae) to STATIC Spinosad ME weathered under operational conditions in California and Florida: a reduced-risk male annihilation treatment.

    PubMed

    Vargas, Roger I; Souder, Steven K; Hoffman, Kevin; Mercogliano, Juan; Smith, Trevor R; Hammond, Jack; Davis, Bobbie J; Brodie, Matt; Dripps, James E

    2014-08-01

    Studies were conducted in 2013-2014 to quantify attraction, feeding, and mortality of male oriental fruit flies, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), to STATIC Spinosad ME a reduced-risk male annihilation treatment (MAT) formulation consisting of an amorphous polymer matrix in combination with methyl eugenol (ME) and spinosad compared with the standard treatment of Min-U-Gel mixed with ME and naled (Dibrom). Our approach used a behavioral methodology for evaluation of slow-acting reduced-risk insecticides. ME treatments were weathered for 1, 7, 14, 21, and 28 d under operational conditions in California and Florida and shipped to Hawaii for bioassays. In field tests using bucket traps to attract and capture wild males, and in toxicity studies conducted in 1-m(3) cages using released males of controlled ages, STATIC Spinosad ME performed equally as well to the standard formulation of Min-U-Gel ME with naled for material aged up to 28 d in both California and Florida. In laboratory feeding tests in which individual males were exposed for 5 min to the different ME treatments, mortality induced by STATIC Spinosad ME recorded at 24 h did not differ from mortality caused by Min-U-Gel ME with naled at 1, 7, 14, and 21 d in California and was equal to or higher for all weathered time periods in Florida during two trials. Spinosad has low contact toxicity, and when mixed with an attractant and slow release matrix, offers a reduced-risk alternative for eradication of B. dorsalis and related ME attracted species, without many of the potential negative effects to humans and nontargets associated with broad-spectrum contact insecticides such as naled. PMID:25195423

  12. Magnetic fields around evolved stars: further observations of H2O maser polarization

    NASA Astrophysics Data System (ADS)

    Leal-Ferreira, M. L.; Vlemmings, W. H. T.; Kemball, A.; Amiri, N.

    2013-06-01

    strength on the surface of the star is found to be between 15.8 and ~1945 G. The magnetic energy of our sources is higher than the thermal and kinetic energy in the H2O maser region of this class of objects. This leads us to conclude that, indeed, magnetic fields probably play an important role in shaping the outflows of evolved stars. Table 7 is available in electronic form at http://www.aanda.org

  13. 76 FR 12563 - Oral Dosage Form New Animal Drugs; Spinosad and Milbemycin Oxime

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    ... prescription use of chewable tablets containing spinosad and milbemycin oxime in dogs for the treatment and... veterinary prescription use of TRIFEXIS (spinosad and milbemycin oxime) Chewable Tablets in dogs for the... Sec. 510.600 of this chapter. (c) Conditions of use in dogs--(1) Amount. Administer once a month at...

  14. Susceptibility status of different life stages of Tribolium castaneum Herbst (Col: Tenebrionidae) to spinosad.

    PubMed

    Yousefnezhad-Irani, Roghayeh; Asghar, Pourmirza Ali

    2007-09-01

    Red flour beetle, Tribolium castaneum, is one the most important and worldwide pest of stored-products. To evaluate the susceptibility of different life stages of this pest we used a commercial formulation of biorational insecticide, Spinosad, Tracer against adults, young and old larvae and pupae using topical application bioassay method. Mortality was recorded after exclusion of pupae and 24, 48 and 72 h posttreatment for the other life stages. Spinosad did not cause pupal mortality. Comparison of LD50 values of different life stages of T. castaneum at 48 h exposure-time revealed that, young larvae and adults were more susceptible to spinosad than the old larvae. Overlapping of 95% CL revealed similarity of susceptibility of young larvae and adult insects to spinosad. Due to compatibility of spinosad with environment, this compound could be considered as a useful tool in the control of the pest in question.

  15. Pharmacokinetics of spinosad and milbemycin oxime administered in combination and separately per os to dogs.

    PubMed

    Holmstrom, S D; Totten, M L; Newhall, K B; Qiao, M; Riggs, K L

    2012-08-01

    Pharmacokinetic (PK) studies were conducted to determine the potential PK interactions when spinosad and milbemycin oxime (MBO) are administered simultaneously. Investigations used commercial MBO tablets (C-MBO; Interceptor(®) Flavor Tabs, active ingredient MBO, Novartis Animal Health, Greensboro, NC, USA), novel-source (Elanco) MBO (E-MBO) in a gelatin capsule, spinosad API (Active Pharmaceutical Ingredient using registered manufacturing process) in a gelatin capsule, spinosad tablets (Comfortis(®) chewable beef flavored tablets, active ingredient spinosad, Elanco Animal Health, Greenfield, IN, USA), and the recently registered spinosad + E-MBO combination tablets (Trifexis™ chewable beef flavored tablets, active ingredients E-MBO and spinosad, Elanco Animal Health, Greenfield, IN, USA). Regardless of the source of MBO, in the presence of spinosad, greater systemic exposure of MBO was obtained as compared to MBO administered alone. Target animal safety studies conducted with dose multiples of spinosad and MBO indicate the increased exposure of MBO does not have implications on adverse clinical reactions. Further research is required to determine whether the higher levels of MBO have any implications for improved effectiveness as compared to C-MBO. Effectiveness studies conducted with 0.5 mg/kg of E-MBO in combination tablets demonstrated noninterference against C-MBO with both products achieving >99% effectiveness against the dose-limiting nematode, Ancylostoma caninum. No statistical differences were detected in the PK of MBO when comparing animals receiving E-MBO (without spinosad) and C-MBO. Also, the PK of spinosad was unaltered when co-administered with MBO. PMID:21895692

  16. Field-Evolved Resistance to Bt Maize by Western Corn Rootworm

    PubMed Central

    Gassmann, Aaron J.; Petzold-Maxwell, Jennifer L.; Keweshan, Ryan S.; Dunbar, Mike W.

    2011-01-01

    Background Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests. However, the evolution of resistance could cut short these benefits. A primary pest targeted by Bt maize in the United States is the western corn rootworm Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). Methodology/Principal Findings We report that fields identified by farmers as having severe rootworm feeding injury to Bt maize contained populations of western corn rootworm that displayed significantly higher survival on Cry3Bb1 maize in laboratory bioassays than did western corn rootworm from fields not associated with such feeding injury. In all cases, fields experiencing severe rootworm feeding contained Cry3Bb1 maize. Interviews with farmers indicated that Cry3Bb1 maize had been grown in those fields for at least three consecutive years. There was a significant positive correlation between the number of years Cry3Bb1 maize had been grown in a field and the survival of rootworm populations on Cry3Bb1 maize in bioassays. However, there was no significant correlation among populations for survival on Cry34/35Ab1 maize and Cry3Bb1 maize, suggesting a lack of cross resistance between these Bt toxins. Conclusions/Significance This is the first report of field-evolved resistance to a Bt toxin by the western corn rootworm and by any species of Coleoptera. Insufficient planting of refuges and non-recessive inheritance of resistance may have contributed to resistance. These results suggest that improvements in resistance management and a more integrated approach to the use of Bt crops may be necessary. PMID:21829470

  17. Field-evolved resistance by western corn rootworm to multiple Bacillus thuringiensis toxins in transgenic maize.

    PubMed

    Gassmann, Aaron J; Petzold-Maxwell, Jennifer L; Clifton, Eric H; Dunbar, Mike W; Hoffmann, Amanda M; Ingber, David A; Keweshan, Ryan S

    2014-04-01

    The widespread planting of crops genetically engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) places intense selective pressure on pest populations to evolve resistance. Western corn rootworm is a key pest of maize, and in continuous maize fields it is often managed through planting of Bt maize. During 2009 and 2010, fields were identified in Iowa in which western corn rootworm imposed severe injury to maize producing Bt toxin Cry3Bb1. Subsequent bioassays revealed Cry3Bb1 resistance in these populations. Here, we report that, during 2011, injury to Bt maize in the field expanded to include mCry3A maize in addition to Cry3Bb1 maize and that laboratory analysis of western corn rootworm from these fields found resistance to Cry3Bb1 and mCry3A and cross-resistance between these toxins. Resistance to Bt maize has persisted in Iowa, with both the number of Bt fields identified with severe root injury and the ability western corn rootworm populations to survive on Cry3Bb1 maize increasing between 2009 and 2011. Additionally, Bt maize targeting western corn rootworm does not produce a high dose of Bt toxin, and the magnitude of resistance associated with feeding injury was less than that seen in a high-dose Bt crop. These first cases of resistance by western corn rootworm highlight the vulnerability of Bt maize to further evolution of resistance from this pest and, more broadly, point to the potential of insects to develop resistance rapidly when Bt crops do not achieve a high dose of Bt toxin.

  18. Tracking vortices in superconductors: Extracting singularities from a discretized complex scalar field evolving in time

    NASA Astrophysics Data System (ADS)

    Phillips, Carolyn L.; Guo, Hanqi; Peterka, Tom; Karpeyev, Dmitry; Glatz, Andreas

    2016-02-01

    In type-II superconductors, the dynamics of magnetic flux vortices determine their transport properties. In the Ginzburg-Landau theory, vortices correspond to topological defects in the complex order parameter field. Earlier, in Phillips et al. [Phys. Rev. E 91, 023311 (2015), 10.1103/PhysRevE.91.023311], we introduced a method for extracting vortices from the discretized complex order parameter field generated by a large-scale simulation of vortex matter. With this method, at a fixed time step, each vortex [simplistically, a one-dimensional (1D) curve in 3D space] can be represented as a connected graph extracted from the discretized field. Here we extend this method as a function of time as well. A vortex now corresponds to a 2D space-time sheet embedded in 4D space time that can be represented as a connected graph extracted from the discretized field over both space and time. Vortices that interact by merging or splitting correspond to disappearance and appearance of holes in the connected graph in the time direction. This method of tracking vortices, which makes no assumptions about the scale or behavior of the vortices, can track the vortices with a resolution as good as the discretization of the temporally evolving complex scalar field. Additionally, even details of the trajectory between time steps can be reconstructed from the connected graph. With this form of vortex tracking, the details of vortex dynamics in a model of a superconducting materials can be understood in greater detail than previously possible.

  19. Field-evolved resistance by western corn rootworm to multiple Bacillus thuringiensis toxins in transgenic maize

    PubMed Central

    Gassmann, Aaron J.; Petzold-Maxwell, Jennifer L.; Clifton, Eric H.; Dunbar, Mike W.; Hoffmann, Amanda M.; Ingber, David A.; Keweshan, Ryan S.

    2014-01-01

    The widespread planting of crops genetically engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) places intense selective pressure on pest populations to evolve resistance. Western corn rootworm is a key pest of maize, and in continuous maize fields it is often managed through planting of Bt maize. During 2009 and 2010, fields were identified in Iowa in which western corn rootworm imposed severe injury to maize producing Bt toxin Cry3Bb1. Subsequent bioassays revealed Cry3Bb1 resistance in these populations. Here, we report that, during 2011, injury to Bt maize in the field expanded to include mCry3A maize in addition to Cry3Bb1 maize and that laboratory analysis of western corn rootworm from these fields found resistance to Cry3Bb1 and mCry3A and cross-resistance between these toxins. Resistance to Bt maize has persisted in Iowa, with both the number of Bt fields identified with severe root injury and the ability western corn rootworm populations to survive on Cry3Bb1 maize increasing between 2009 and 2011. Additionally, Bt maize targeting western corn rootworm does not produce a high dose of Bt toxin, and the magnitude of resistance associated with feeding injury was less than that seen in a high-dose Bt crop. These first cases of resistance by western corn rootworm highlight the vulnerability of Bt maize to further evolution of resistance from this pest and, more broadly, point to the potential of insects to develop resistance rapidly when Bt crops do not achieve a high dose of Bt toxin. PMID:24639498

  20. Susceptibility of field populations of the diamondback moth, Plutella xylostella, to a selection of insecticides in Central China.

    PubMed

    Zhang, Shuzhen; Zhang, Xiaolei; Shen, Jun; Mao, Kaikai; You, Hong; Li, Jianhong

    2016-09-01

    The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. However, resistance to insecticides evolves following heavy and frequent use. Therefore, the insecticide resistance in field populations of P. xylostella collected from Central China from 2013 to 2014 was determined with a leaf-dipping method. Based on the results of the monitoring, P. xylostella has developed high levels of resistance to beta-cypermethrin (resistance ratio=69.76-335.76-fold), Bt (WG-001) (RR=35.43-167.36), and chlorfluazuron (RR=13.60-104.95) and medium levels of resistance to chlorantraniliprole (RR=1.19-14.26), chlorfenapyr (RR=4.22-13.44), spinosad (RR=5.89-21.45), indoxacarb (RR=4.01-34.45), and abamectin (RR=23.88-95.15). By contrast, the field populations of P. xylostella remained susceptible to or developed low levels of resistance to diafenthiuron (RR=1.61-8.05), spinetoram (RR=0.88-2.35), and cyantraniliprole (RR=0.4-2.15). Moreover, the LC50 values of field populations of P. xylostella were highly positively correlated between chlorantraniliprole and cyantraniliprole (r=0.88, P=0.045), chlorantraniliprole and spinosad (r=0.66, P=0.039), spinosad and diafenthiuron (r=0.57, P=0.0060), and chlorfenapyr and diafenthiuron (r=0.51, P=0.016). Additionally, the activities of detoxification enzymes in field populations of P. xylostella were significantly positively correlated with the log LC50 values of chlorantraniliprole and spinosad. The results of this study provide an important base for developing effective and successful strategies to manage insecticide resistance in P. xylostella. PMID:27521911

  1. Susceptibility of field populations of the diamondback moth, Plutella xylostella, to a selection of insecticides in Central China.

    PubMed

    Zhang, Shuzhen; Zhang, Xiaolei; Shen, Jun; Mao, Kaikai; You, Hong; Li, Jianhong

    2016-09-01

    The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. However, resistance to insecticides evolves following heavy and frequent use. Therefore, the insecticide resistance in field populations of P. xylostella collected from Central China from 2013 to 2014 was determined with a leaf-dipping method. Based on the results of the monitoring, P. xylostella has developed high levels of resistance to beta-cypermethrin (resistance ratio=69.76-335.76-fold), Bt (WG-001) (RR=35.43-167.36), and chlorfluazuron (RR=13.60-104.95) and medium levels of resistance to chlorantraniliprole (RR=1.19-14.26), chlorfenapyr (RR=4.22-13.44), spinosad (RR=5.89-21.45), indoxacarb (RR=4.01-34.45), and abamectin (RR=23.88-95.15). By contrast, the field populations of P. xylostella remained susceptible to or developed low levels of resistance to diafenthiuron (RR=1.61-8.05), spinetoram (RR=0.88-2.35), and cyantraniliprole (RR=0.4-2.15). Moreover, the LC50 values of field populations of P. xylostella were highly positively correlated between chlorantraniliprole and cyantraniliprole (r=0.88, P=0.045), chlorantraniliprole and spinosad (r=0.66, P=0.039), spinosad and diafenthiuron (r=0.57, P=0.0060), and chlorfenapyr and diafenthiuron (r=0.51, P=0.016). Additionally, the activities of detoxification enzymes in field populations of P. xylostella were significantly positively correlated with the log LC50 values of chlorantraniliprole and spinosad. The results of this study provide an important base for developing effective and successful strategies to manage insecticide resistance in P. xylostella.

  2. Long-term persistence and efficacy of spinosad against Rhyzopertha dominica (Coleoptera: Bostrychidae) in wheat.

    PubMed

    Daglish, Gregory J; Nayak, Manoj K

    2006-02-01

    A laboratory study was undertaken to determine the persistence and efficacy of spinosad against Rhyzopertha dominica (F.) in wheat stored for 9 months at 30 degrees C and 55 and 70% relative humidity. The aim was to investigate the potential of spinosad for protecting wheat from R. dominica during long-term storage in warm climates. Wheat was treated with spinosad at 0.1, 0.5 and 1 mg kg(-1) grain and sampled after 0, 1.5, 3, 4.5, 6, 7.5 and 9 months of storage for bioassays and residue analyses. Residues were estimated to have declined by 30% during 9 months of storage at 30 degrees C and there was no effect of relative humidity. Spinosad applied at 0.5 or 1 mg kg(-1) was completely effective for 9 months, with 100% adult mortality after 14 days of exposure and no live F1 adults produced. Adult mortality was <100% in some samples of wheat treated with 0.1 mg kg(-1) of spinosad, and live progeny were produced in all samples treated at this level. The results show that spinosad is likely to be an effective grain protectant against R. dominica in wheat stored in warm climates.

  3. Lack of genotoxic potential of pesticides, spinosad, imidacloprid and neem oil in mice (Mus musculus).

    PubMed

    Saxena, Ankita; Kesari, V P

    2016-03-01

    Pesticides, spinosad, imidacloprid and neem oil are widely used both in residential and agricultural environments because of its broad spectrum insecticidal activity and effectiveness. The present study was undertaken to estimate genotoxicity of formulations of some pesticides in mice. Three pesticides of diverse group studied were spinosad (45% w/v), imidacloprid (17.8%, w/v) and neem oil. Animals were exposed 37, 4.5 and 50 mg kg⁻¹ b.wt. for spinosad, imidacloprid and neem oil, respectively, through oral gavage for 5 consecutive days. A vehicle control group and one positive control (cyclophosphamide; 20 mg kg⁻¹ b. wt.) were also selected. The results showed that cyclophosphamide produced 1.12% micronuclei in mice, as against 0.18 in vehicle control, 0.30 in spinosad, 0.28 in imidacloprid and 0.22% in neem oil, respectively. The gross percentage of chromosomal aberration in mice were 28.5% in cyclophosphamide against 6.5% in vehicle control, 8.0% in spinosad, 9.5% in imidacloprid and 7.0% in neem oil, respectively. The overall findings of the present study revealed that all the three pesticide formulations, imidacloprid, spinosad and neem oil at tested dose did not show any genotoxic effect in mice.

  4. Lack of genotoxic potential of pesticides, spinosad, imidacloprid and neem oil in mice (Mus musculus).

    PubMed

    Saxena, Ankita; Kesari, V P

    2016-03-01

    Pesticides, spinosad, imidacloprid and neem oil are widely used both in residential and agricultural environments because of its broad spectrum insecticidal activity and effectiveness. The present study was undertaken to estimate genotoxicity of formulations of some pesticides in mice. Three pesticides of diverse group studied were spinosad (45% w/v), imidacloprid (17.8%, w/v) and neem oil. Animals were exposed 37, 4.5 and 50 mg kg⁻¹ b.wt. for spinosad, imidacloprid and neem oil, respectively, through oral gavage for 5 consecutive days. A vehicle control group and one positive control (cyclophosphamide; 20 mg kg⁻¹ b. wt.) were also selected. The results showed that cyclophosphamide produced 1.12% micronuclei in mice, as against 0.18 in vehicle control, 0.30 in spinosad, 0.28 in imidacloprid and 0.22% in neem oil, respectively. The gross percentage of chromosomal aberration in mice were 28.5% in cyclophosphamide against 6.5% in vehicle control, 8.0% in spinosad, 9.5% in imidacloprid and 7.0% in neem oil, respectively. The overall findings of the present study revealed that all the three pesticide formulations, imidacloprid, spinosad and neem oil at tested dose did not show any genotoxic effect in mice. PMID:27097450

  5. Spectropolarimetry of Giant stars: Probing the influence of magnetic field on evolved stars Spectropolarimetry of Giant stars: Probing the influence of magnetic field on evolved stars

    NASA Astrophysics Data System (ADS)

    da Costa, Jefferson; Castro, Matthieu; Petit, Pascal; do Nascimento, José-Dias, Jr.

    2015-08-01

    It is know that lithium is element easily destroyed in stellar interior, the existence of lithium rich stars means a great challenge in stellar evolution. In this context our observations ravels the serendipitous discovery of an unusually high lithium abundance star. This is a K0III HD 150050, which has strong deepening on lithium line (6707.8 Å) this means lithium abundance of 2.81 0.2 dex, therefore this star belong a rare group called super Li-Rich stars. A possible source of the non-standard episodes required to produce Li-rich stars were identified in magneto-thermohaline mixing accounted by models of extra-mixing induced by magnetic buoyancy. However to better understand this is necessary more observational data. In last three decades several studies has showed that late type red giant stars presents a remarkable modifications in these outer atmosphere layers when they become late type star in HR diagram. These changes are founded through X-ray, Ultraviolet, and Chromospheric activity analyses, and then we can establish the called “Dividing lines”. We made spectropalarimetric observations with ESPaDOnS@CFHT to achieve two main objectives: analyze the influence of magnetic field in the Li-rich giant stars, and understand how works the magnetic field in late type giants and supergiants across the “dividing line”.

  6. EHWPACK: An evolvable hardware environment using the SPICE simulator and the Field Programmable Transistor Array

    NASA Technical Reports Server (NTRS)

    Keymeulen, D.; Klimeck, G.; Zebulum, R.; Stoica, A.; Jin, Y.; Lazaro, C.

    2000-01-01

    This paper describes the EHW development system, a tool that performs the evolutionary synthesis of electronic circuits, using the SPICE simulator and the Field Programmable Transistor Array hardware (FPTA) developed at JPL.

  7. Early detection of field-evolved resistance to Bt cotton in China: cotton bollworm and pink bollworm.

    PubMed

    Tabashnik, Bruce E; Wu, Kongming; Wu, Yidong

    2012-07-01

    Transgenic crops producing Bacillus thuringiensis (Bt) toxins kill some major insect pests, but pests can evolve resistance and thereby reduce the effectiveness of such Bt crops. The main approach for slowing pest adaptation to Bt crops uses non-Bt host plants as "refuges" to increase survival of susceptible pests. To delay evolution of pest resistance to cotton producing Bt toxin Cry1Ac, several countries have required refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. This strategy is designed for cotton bollworm (Helicoverpa armigera), which attacks many crops and is the primary target of Bt cotton in China, but it does not apply to pink bollworm (Pectinophora gossypiella), which feeds almost entirely on cotton in China. Here we review evidence of field-evolved resistance to Cry1Ac by cotton bollworm in northern China and by pink bollworm in the Yangtze River Valley of China. For both pests, results of laboratory diet bioassays reveal significantly decreased susceptibility of field populations to Cry1Ac, yet field control failures of Bt cotton have not been reported. The early detection of resistance summarized here may spur countermeasures such as planting Bt cotton that produces two or more distinct toxins, increased planting of non-Bt cotton, and integration of other management tactics together with Bt cotton.

  8. Direct Nanoscale Imaging of Evolving Electric Field Domains in Quantum Structures

    PubMed Central

    Dhar, Rudra Sankar; Razavipour, Seyed Ghasem; Dupont, Emmanuel; Xu, Chao; Laframboise, Sylvain; Wasilewski, Zbig; Hu, Qing; Ban, Dayan

    2014-01-01

    The external performance of quantum optoelectronic devices is governed by the spatial profiles of electrons and potentials within the active regions of these devices. For example, in quantum cascade lasers (QCLs), the electric field domain (EFD) hypothesis posits that the potential distribution might be simultaneously spatially nonuniform and temporally unstable. Unfortunately, there exists no prior means of probing the inner potential profile directly. Here we report the nanoscale measured electric potential distribution inside operating QCLs by using scanning voltage microscopy at a cryogenic temperature. We prove that, per the EFD hypothesis, the multi-quantum-well active region is indeed divided into multiple sections having distinctly different electric fields. The electric field across these serially-stacked quantum cascade modules does not continuously increase in proportion to gradual increases in the applied device bias, but rather hops between discrete values that are related to tunneling resonances. We also report the evolution of EFDs, finding that an incremental change in device bias leads to a hopping-style shift in the EFD boundary – the higher electric field domain expands at least one module each step at the expense of the lower field domain within the active region. PMID:25431158

  9. Currents in Environmental Education: Mapping a Complex and Evolving Pedagogical Field

    ERIC Educational Resources Information Center

    Sauve, Lucie

    2005-01-01

    The purpose of this article is to bring to light and celebrate the richness of the environmental education field, thereby paying homage to the pedagogical creativity of its architects over the course of the last thirty years, as well as to their contribution in reflecting on the meaning, problems and possibilities of our relationship to the…

  10. NON-EQUILIBRIUM CHEMISTRY OF DYNAMICALLY EVOLVING PRESTELLAR CORES. II. IONIZATION AND MAGNETIC FIELD

    SciTech Connect

    Tassis, Konstantinos; Willacy, Karen; Yorke, Harold W.; Turner, Neal J.

    2012-07-20

    We study the effect that non-equilibrium chemistry in dynamical models of collapsing molecular cloud cores has on measurements of the magnetic field in these cores, the degree of ionization, and the mean molecular weight of ions. We find that OH and CN, usually used in Zeeman observations of the line-of-sight magnetic field, have an abundance that decreases toward the center of the core much faster than the density increases. As a result, Zeeman observations tend to sample the outer layers of the core and consistently underestimate the core magnetic field. The degree of ionization follows a complicated dependence on the number density at central densities up to 10{sup 5} cm{sup -3} for magnetic models and 10{sup 6} cm{sup -3} in non-magnetic models. At higher central densities, the scaling approaches a power law with a slope of -0.6 and a normalization which depends on the cosmic-ray ionization rate {zeta} and the temperature T as ({zeta}T){sup 1/2}. The mean molecular weight of ions is systematically lower than the usually assumed value of 20-30, and, at high densities, approaches a value of 3 due to the asymptotic dominance of the H{sup +}{sub 3} ion. This significantly lower value implies that ambipolar diffusion operates faster.

  11. Effects of spinosad and neem on the efficacy of a nucleopolyhedrovirus on pickleworm larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A neem formulation (Neemix® 4.5) and spinosad (SpinTor® 2SC) were tested for their effects when mixed with the multicapsid nucleopolyhedrovirus virus (AgMNPV) from the velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), for control of pickleworm larvae, Diaphania nitidalis...

  12. Spinosad in the native stingless bee Melipona quadrifasciata: regrettable non-target toxicity of a bioinsecticide.

    PubMed

    Tomé, Hudson Vaner V; Barbosa, Wagner F; Martins, Gustavo F; Guedes, Raul Narciso C

    2015-04-01

    The risks imposed by novel insecticides, mainly bioinsecticides, are largely unknown despite their increased use and their perceived environmental safety, which is based on their natural origin. Furthermore, unlike honeybees, native pollinator species have received little attention. In the present study, the lethal and sublethal effects of the neonicotinoid imidacloprid and the bioinsecticide spinosad were assessed in the stingless bee species Meliponaquadrifasciata, an important native pollinator in the Neotropical region. The adult stingless bee workers exhibited high oral insecticide susceptibility, with LD50s of 23.54 and 12.07 ng a.i./bee for imidacloprid and spinosad, respectively. Imidacloprid also impaired worker respiration and overall group activity and flight, while spinosad significantly impaired only worker flight despite exhibiting higher oral toxicity to adult workers than imidacloprid. These findings indicate the hazardous nature not only of imidacloprid but also the bioinsecticide spinosad to adult workers of the native pollinator M. quadrifasciata. Therefore, bioinsecticides should not be exempted from risk assessment analysis due to their lethal and sublethal components.

  13. Familial colon cancer syndromes: an update of a rapidly evolving field.

    PubMed

    Patel, Swati G; Ahnen, Dennis J

    2012-10-01

    Colorectal cancer (CRC) is a major cause of morbidity and mortality in the world. Up to 30 % of CRCs have evidence of a familial component, and about 5 % are thought to be due to well-characterized inherited mutations. This review will focus on recent developments in the understanding of the individual hereditary CRC syndromes, including Lynch syndrome, familial CRC type X, familial adenomatous polyposis, MutYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, PTEN hamartomatous syndrome, and serrated polyposis syndrome. Advances within the area of hereditary colon cancer syndromes paint a picture of a rapidly moving, rapidly maturing, and increasingly collaborative field with many opportunities for ongoing research and development.

  14. Lower Crustal Seismicity, Volatiles, and Evolving Strain Fields During the Initial Stages of Cratonic Rifting

    NASA Astrophysics Data System (ADS)

    Lambert, C.; Muirhead, J.; Ebinger, C. J.; Tiberi, C.; Roecker, S. W.; Ferdinand-Wambura, R.; Kianji, G.; Mulibo, G. D.

    2014-12-01

    The volcanically active East African rift system in southern Kenya and northern Tanzania transects thick cratonic lithosphere, and comprises several basins characterized by deep crustal seismicity. The US-French-Tanzania-Kenya CRAFTI project aims to understand the role of magma and volatile movement during the initiation and evolution of rifting in cratonic lithosphere. Our 38-station broadband network spans all or parts of fault-bounded rift segments, enabling comparison of lithospheric structure, fault kinematics, and seismogenic layer thickness with age and proximity to the deeply rooted Archaen craton. Seismicity levels are high in all basins, but we find profound differences in seismogenic layer thickness along the length of the rift. Seismicity in the Manyara basin occurs almost exclusively within the lower crust, and in spatial clusters that have been active since 1990. In contrast, seismicity in the ~ 5 My older Magadi basin is localized in the upper crust, and the long border fault bounding the west side of the basin is seismically inactive. Between these two basins lies the Natron rift segment, which shows seismicity between ~ 20 and ~2 km depth, and high concentrations at Oldoinyo Lengai and Gelai volcanoes. Older volcanoes on the uplifted western flank (e.g., Ngorongoro) experience swarms of activity, suggesting that active magmatism and degassing are widespread. Focal mechanisms of the frequent earthquakes recorded across the array are spatially variable, and indicate a stress field strongly influenced by (1) Holocene volcanoes, (2) mechanical interactions between adjacent rift basins, and (3) a far-field ESE-WNW extensional stress regime. We explore the spatial correlation between zones of intense degassing along fault systems and seismicity, and examine the influence of high gas pressures on lower and upper crustal seismicity in this youthful cratonic rift zone.

  15. Laboratory evaluation of pyriproxyfen and spinosad, alone and in combination, against Aedes aegypti larvae.

    PubMed

    Darriet, Frederic; Corbel, Vincent

    2006-11-01

    In this study, the efficacy of pyriproxyfen and spinosad, alone and in combination, was evaluated against the dengue vector Aedes aegypti (L.). Larval bioassays were carried out on susceptible mosquito larvae to determine the concentration-mortality responses of mosquitoes exposed to each insecticide alone and in mixture. Synergism between pyriproxyfen and spinosad was determined by the calculation of a combination index (CI) by using the isobologram method. For pyriproxyfen, LC50 and LC95 were 1.1 x 10(-4) (1.0 x 10(-4)-1.1 x 10(-4)) and 3.2 x 10(-4) (2.9 x 10(-4)-3.6 x 10(-4)) mg/liter, respectively. Pyriproxyfen acted at very low concentrations by inhibiting the adult emergence of Ae. aegypti (97% inhibition rates at 3.3 x 10(-4) mg/liter). Spinosad activity was -500 times lower than that of pyriproxyfen against the Bora strain, with LC50 and LC95 values estimated at 0.055 (0.047-0.064) and 0.20 (0.15-0.27) mg/liter, respectively. A binary mixture of pyriproxyfen and spinosad was realized at the ratio 1:500 by considering the values of the LC50 obtained for each product. The LC50 and LC95 of the mixture were 0.019 (0.016 - 0.022) and 0.050 (0.040 - 0.065) mg/liter, respectively. The mixture combined both the larvicidal activity of spinosad and the juvenoid action of pyriproxyfen. From the LC70 to LC99 a significant synergism effect was observed between the two insecticides (CI ranged from 0.74 to 0.31). This strong synergism observed at high concentrations allows a reduction by five and nine-fold of pyriproxyfen and spinosad amounts to kill almost 100% mosquitoes. Combination of pyriproxyfen and spinosad may then represent a promising strategy to improve mosquito control in situations with insecticide-resistant Aedes dengue vectors.

  16. Efficacy of spinosad and methoprene, applied alone or in combination, against six stored-product insect species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efficacy of the insecticides spinosad and methoprene, applied alone or in combination to wheat, was evaluated against six stored-product insect species, Rhyzopertha dominica, Sitophilus oryzae, S. granarius, Cryptolestes ferrugineus, Oryzaephilus surinamensis, and Liposcelis bostrychophila. The conc...

  17. Insecticidal effect of spinosad dust, in combination with diatomaceous earth, against two stored-grain beetle species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efficacy of the biological insecticide spinosad applied alone and combination with diatomaceous earth (DE) was determined through laboratory bioassays with adults of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and the confused flour beetle, Tribolium confusum Jacquelin du Val...

  18. Liquid chromatography-tandem mass spectrometric methods for the determination of spinosad, thiacloprid and pyridalyl in spring onions and estimation of their pre-harvest interval values.

    PubMed

    Dasenaki, Marilena E; Bletsou, Anna A; Hanafi, Ahmad H; Thomaidis, Nikolaos S

    2016-12-15

    Two liquid chromatography-tandem mass spectrometric methods were developed and validated to determine spinosyn A and D, thiacloprid and pyridalyl in spring onions cultivated under Egyptian field conditions. The degradation rates, the pre-harvest interval (PHI) values and the half-life values of the three pesticides were estimated. QuEChERS was used for sample preparation and the separation was performed on an X-Bridge C18 column with ACN-formic acid 0.1% as the mobile phase. Linear range, method detection limits (MDLs), precision, recovery and matrix effects were estimated. The multi-residue MDLs ranged from 0.02μg/kg (spinosyn A & D) to 0.05μg/kg for pyridalyl. All the investigated pesticides showed high degradation rates. For spinosad the half-life value was 1.2days, for thiacloprid it reached 2.2days and for pyridalyl 4.4days. Furthermore, the calculated PHI values, according to the maximum residue levels set by the EU, were 0days for spinosad, 9.8days for thiacloprid and 39.4days for pyridalyl. PMID:27451196

  19. Disruption of the naturally evolved N conservation strategy in soil under grassland at a sports field in York, UK.

    PubMed

    Bhatti, Ambreen; Cresser, Malcolm S

    2014-11-01

    Water- and KCl-extractable ammonium-N and nitrate-N concentrations have been monitored at approximately monthly intervals over a year in soils from 0-10 and 10-20 cm depths under permanent grass at a sports field in York, UK. Measurements were made on both fresh, field-moist soils and after the same soils had been incubated for 7 days at ambient outdoor temperatures, to assess seasonal changes in the capacity of the soils to produce mineral-N species in the absence of plant uptake and other effects. Water extracts allowed potential mobility of N species to be assessed. Comparison of seasonal trends in mineral-N species concentrations in pre- and post-incubation soils confirmed depletion of exchangeable ammonium-N from the winter to summer. Mineral-N in fresh and incubated soils displayed summer minima and also low production in winter, associated with the effects of low temperature on nitrate production and probably microbial immobilization of nitrate produced by residual senescent plant litter with a higher C:N ratio from the previous autumn. The results support the concept that plant/soil systems co-evolved under more pristine conditions to conserve soil N by matching the dynamics of soil mineral N production and plant N uptake, but now N pollution has resulted in a dynamic mismatch.

  20. Rhipicephalus annulatus (Acari: Ixodidae) Control by Nigella sativa, Thyme and Spinosad Preparations

    PubMed Central

    Aboelhadid, Shawky Mohamed; Mahran, Hesham A; El-Hariri, Hazem M; Shokier, Khalid Mohamed

    2016-01-01

    Background: Several compounds obtained from plants have potential insecticidal, growth deterrent or repellent characteristics. The control of hard ticks by non-chemical substances was targeted in this study. Methods: The effect of 36 materials on in-vitro ticks was studied, including 2 absolute controls (water only or absolute ethyl alcohol only), 6 conventionally used spinosad preparations (aqueous solutions), 12 Nigella sativa (N. sativa) preparations (aqueous and alcoholic solutions), and 12 Thyme preparations (aqueous and alcoholic solutions). The engorged ticks were tested in-vitro for mortality and oviposition ability using the studied materials. Results: The final mortality after 48 hours of application in N. sativa aqueous preparations began from 10.0% concentration, 1.0% to 100% by concentration preparations ≥10%. In addition, N. sativa alcoholic preparations began from 50.0% concentration, 2 % to 100% by concentration ≥5%. Meanwhile, Thyme aqueous and alcoholic preparations began from 70.0% concentration, 5% to 90% by concentration 10–20%. Additionally, spinosad aqueous preparations and both of control preparations (Water and Alcohol) resulted in no mortality. All differences were statistically significant. The oviposition was stopped in N. sativa (aqueous ≥10% and alcoholic ≥5%) and in spinosad (aqueous≥25%). The aqoues dilution of the used matters killed B. annulatus larvae beginning from the concentration 5%. Conclusion: Nigella sativa alcohol 20% was the best of studied preparations being the lowest concentration (20%) that could achieve the highest lethal (100%) effect in shortest time (12 hours). Moreover, Thyme oil and spinosad could not kill 100% of adult but did on larvae. PMID:27308273

  1. The development of spinosad for the control of Frankliniella occidentalis in protected ornamentals.

    PubMed

    Drinkall, M J; Boogaard, M

    2001-01-01

    Fifteen trials were undertaken to determine the effectiveness of spinosad for the control of Frankliniella occidentalis on a range of glasshouse ornamentals. A range of dose rates were tested from 6-15 g as hl-1. A high level of control (> 90%) was achieved at most assessments of both nymphs and adults with a comparatively flat dose response recorded. Rates of 9 g as hl-1 and above provided improved consistency of control compared with the lower rate of 6 g as hl-1 across trials. No adverse effect was recorded from eight selectivity trials completed on a range of pot plants and cut flowers at rates up to 72 g as hl-1 with the exception of Saintpaulia ionantha. On this highly sensitive species some spotting of the flowers occurred following application rates of spinosad applied at 24 g as hl-1 and above. It is considered that the high level of activity of spinosad combined with its excellent plant safety profile will be of significant benefit to growers for the control of a major insect pest of glasshouse ornamentals. PMID:12425059

  2. Laboratory selection of resistance to spinosad in Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Su, Tianyun; Cheng, Min-Lee

    2014-03-01

    A southern house mosquito Culex quinquefasciatus Say colony was established from surviving late instars and pupae from a semifield evaluation on Natular XRG (a granular formulation containing 2.5% spinosad). The initial lethal levels ofNatular XRG against this colony were determined in the laboratory for the first-generation progeny (designated as F1). Selection pressure was applied at LC70-90 levels to 10,000-15,000 late third- and early fourth-instar larvae of each generation with Natular XRG. Susceptibility changes in response to selection were determined every other generation, where a gradual and steady decline in susceptibility occurred from generation F1 to F35, followed by significant decline from generations F37 to F45 For reference purposes, susceptibility of freshly collected wild populations as well as a laboratory colony of the same species was also determined concurrently, which fluctuated within a slightly wider range for the wild populations and a tighter range for the laboratory colony. By comparing with wild populations and laboratory reference colony, tolerance to spinosad was observed from generations up to F9 in the selected population. Resistance levels increased gradually from generation F11 to F35, and elevated significantly from generations F37 to F45, when resistance ratios reached 1,415.3- to 2,229.9-fold at LC50 and 9,613.1- to 17,062.6-fold at LC90. Possible mechanisms of resistance development to spinosad were discussed.

  3. The development of spinosad for the control of Frankliniella occidentalis in protected ornamentals.

    PubMed

    Drinkall, M J; Boogaard, M

    2001-01-01

    Fifteen trials were undertaken to determine the effectiveness of spinosad for the control of Frankliniella occidentalis on a range of glasshouse ornamentals. A range of dose rates were tested from 6-15 g as hl-1. A high level of control (> 90%) was achieved at most assessments of both nymphs and adults with a comparatively flat dose response recorded. Rates of 9 g as hl-1 and above provided improved consistency of control compared with the lower rate of 6 g as hl-1 across trials. No adverse effect was recorded from eight selectivity trials completed on a range of pot plants and cut flowers at rates up to 72 g as hl-1 with the exception of Saintpaulia ionantha. On this highly sensitive species some spotting of the flowers occurred following application rates of spinosad applied at 24 g as hl-1 and above. It is considered that the high level of activity of spinosad combined with its excellent plant safety profile will be of significant benefit to growers for the control of a major insect pest of glasshouse ornamentals.

  4. A nicotinic acetylcholine receptor transmembrane point mutation (G275E) associated with resistance to spinosad in Frankliniella occidentalis

    PubMed Central

    Puinean, Alin M; Lansdell, Stuart J; Collins, Toby; Bielza, Pablo; Millar, Neil S

    2013-01-01

    High levels of resistance to spinosad, a macrocyclic lactone insecticide, have been reported previously in western flower thrips, Frankliniella occidentalis, an economically important insect pest of vegetables, fruit and ornamental crops. We have cloned the nicotinic acetylcholine receptor (nAChR) α6 subunit from F. occidentalis (Foα6) and compared the nucleotide sequence of Foα6 from susceptible and spinosad-resistant insect populations (MLFOM and R1S respectively). A single nucleotide change has been identified in Foα6, resulting in the replacement of a glycine (G) residue in susceptible insects with a glutamic acid (E) in resistant insects. The resistance-associated mutation (G275E) is predicted to lie at the top of the third α-helical transmembrane domain of Foα6. Although there is no direct evidence identifying the location of the spinosad binding site, the analogous amino acid in the C. elegans glutamate-gated chloride channel lies in close proximity (4.4 Å) to the known binding site of ivermectin, another macrocyclic lactone pesticide. The functional consequences of the resistance-associated mutation have been examined in the human nAChR α7 subunit. Introduction of an analogous (A272E) mutation in α7 abolishes the modulatory effects of spinosad whilst having no significant effect upon activation by acetylcholine, consistent with spinosad having an allosteric mechanism of action. PMID:23016960

  5. Life has Evolved to Evolve

    NASA Astrophysics Data System (ADS)

    Deem, Michael

    2006-03-01

    Concomitant with the evolution of biological diversity must have been the evolution of mechanisms that facilitate evolution, due to the essentially infinite complexity of protein sequence space. We describe how evolvability can be an object of Darwinian selection, emphasizing the collective nature of the process. Rapid or dramatic environmental change leads to selection for greater evolvability. The selective pressure for large scale genetic moves, such as DNA exchange, becomes increasingly strong as the environmental conditions become more uncertain. These results demonstrate that evolvability is a selectable trait and allow for the explanation of a large body of experimental results. Many observations within evolutionary biology, heretofore considered evolutionary happenstance or accidents, are explained by selection for evolvability. As specific examaples, we discuss evolution within the immune system and evolution of drug resistant microrganisims.

  6. Alternative Splicing and Highly Variable Cadherin Transcripts Associated with Field-Evolved Resistance of Pink Bollworm to Bt Cotton in India

    PubMed Central

    Fabrick, Jeffrey A.; Ponnuraj, Jeyakumar; Singh, Amar; Tanwar, Raj K.; Unnithan, Gopalan C.; Yelich, Alex J.; Li, Xianchun; Carrière, Yves; Tabashnik, Bruce E.

    2014-01-01

    Evolution of resistance by insect pests can reduce the benefits of insecticidal proteins from Bacillus thuringiensis (Bt) that are used extensively in sprays and transgenic crops. Despite considerable knowledge of the genes conferring insect resistance to Bt toxins in laboratory-selected strains and in field populations exposed to Bt sprays, understanding of the genetic basis of field-evolved resistance to Bt crops remains limited. In particular, previous work has not identified the genes conferring resistance in any cases where field-evolved resistance has reduced the efficacy of a Bt crop. Here we report that mutations in a gene encoding a cadherin protein that binds Bt toxin Cry1Ac are associated with field-evolved resistance of pink bollworm (Pectinophora gossypiella) in India to Cry1Ac produced by transgenic cotton. We conducted laboratory bioassays that confirmed previously reported resistance to Cry1Ac in pink bollworm from the state of Gujarat, where Bt cotton producing Cry1Ac has been grown extensively. Analysis of DNA from 436 pink bollworm from seven populations in India detected none of the four cadherin resistance alleles previously reported to be linked with resistance to Cry1Ac in laboratory-selected strains of pink bollworm from Arizona. However, DNA sequencing of pink bollworm derived from resistant and susceptible field populations in India revealed eight novel, severely disrupted cadherin alleles associated with resistance to Cry1Ac. For these eight alleles, analysis of complementary DNA (cDNA) revealed a total of 19 transcript isoforms, each containing a premature stop codon, a deletion of at least 99 base pairs, or both. Seven of the eight disrupted alleles each produced two or more different transcript isoforms, which implicates alternative splicing of messenger RNA (mRNA). This represents the first example of alternative splicing associated with field-evolved resistance that reduced the efficacy of a Bt crop. PMID:24840729

  7. Spinosad Induces Antioxidative Response and Ultrastructure Changes in Males of Red Palm Weevil Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae)

    PubMed Central

    Abdelsalam, Salaheldin A.; Alzahrani, Abdullah M.; Elmenshawy, Omar M.; Abdel-Moneim, Ashraf M.

    2016-01-01

    The red palm weevil, Rhynchophorus ferrugineus, is of great concern worldwide, especially in the Middle East, where dates are a strategic crop. Despite their ecological hazard, insecticides remain the most effective means of control. A bioinsecticide of bacterial origin, spinosad is effective against several pests, and its efficacy against male R. ferrugineus was assessed in the present study. The antioxidative responses of key enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST) to spinosad were investigated in the midgut and testes, and the effects of this insecticide on the cell ultrastructure of the midgut, Malpighian tubules, and testes were also determined. The lethal concentration 50 of spinosad was measured at 58.8 ppm, and the insecticide inhibited the activities of CAT, SOD, and GST in the midgut. However, no significant changes in the activities of these enzymes were observed in the testes. Spinosad treatment resulted in concentration-dependent changes in the cellular organelles of the midgut, Malpighian tubules, and testes of R. ferrugineus, and some of these effects were similar to those exerted by other xenobiotics. However, specific changes were observed as a result of spinosad treatment, including an increase in the number and size of concretions in Malpighian tubule cells and the occasional absence of the central pair of microtubules in the axonemes of sperm tails. This study introduces spinosad for potential use as an insecticide within an integrated control program against male red palm weevils. Additionally, the study provides biochemical and ultrastructural evidence for use in the development of bioindicators.

  8. Interactions between Entomopathogenic Fungus, Metarhizium anisopliae and Sublethal Doses of Spinosad for Control of House Fly, Musca domestica

    PubMed Central

    Sharififard, M; Mossadegh, MS; Vazirianzadeh, B; Zarei-Mahmoudabadi, A

    2011-01-01

    Background: Metarhizium anisopliae strain IRAN 437C is one of the most virulent fungal isolates against house fly, Musca domestica. The objective of this study was to determine the interaction of this isolate with sublethal doses of spinosad against housefly. Methods: In adult bioassay, conidia of entomopathogenic fungus were applied as inoculated bait at 105 and 107 spore per gram and spinosad at 0.5, 1 and 1.5 μg (A.I.) per gram bait. In larval bioassay, conidia were applied as combination of spore with larval bedding at 106 and 108 spore per gram and spinosad at sublethals of 0.002, 0.004 and 0.006 μg (AI) per gram medium. Results: Adult mortality was 48% and 72% for fungus alone but ranged from 66–87% and 89–95% in combination treatments of 105 and 107 spore/g with sublethal doses of spinosad respectively. The interaction between 105 spore/g with sublethals exhibited synergistic effect, but in combination of 107 spore in spite of higher mortality, the interaction was additive. There was significant difference in LT50 among various treatments. LT50 values in all combination treatments were smaller than LT50 values in alone ones. Larval mortality was 36% and 69% for fungus alone but ranged from 58%–78% and 81%–100% in combination treatments of 106 and 108 spore/g medium with sublethals of spinosad respectively. The interaction was synergistic in all combination treatments of larvae. Conclusion: The interaction between M. anispliae and spinosad indicated a synergetic effect that increased the house fly mortality as well as reduced the lethal time. PMID:22808408

  9. Immediate and delayed mortality of Rhyzopertha dominica (Coleoptera: Bostrichidae) and Sitophilus oryzae (Coleoptera: Curculionidae) adults exposed to spinosad-treated commodities.

    PubMed

    Getchell, Anna Iversen; Subramanyam, Bhadriraju

    2008-06-01

    A series of tests was conducted to characterize differences in the mortality of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), and rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), exposed to three commodities treated with a liquid and dry spinosad formulation. In laboratory bioassays, adults of the two insect species were exposed to untreated wheat, Triticum aestivum L., corn, Zea mays L., and sorghum, Sorghum bicolor (L.) Moench., and to commodities treated with 1 mg (AI)/kg of liquid and dry spinosad formulations. Mortality was assessed from independent samples examined at specific time intervals to determine immediate mortality and after 24 h of recovery on untreated grain at 28 degrees C and 65% RH to determine delayed mortality. Comparison of the time required for 50% (LT50) and 95% (LT95) mortality indicated that R. dominica adults were consistently and significantly more susceptible (died quickly) than S. oryzae adults when exposed to spinosad-treated commodities. In general, the toxicity of liquid and dry spinosad formulations was similar against R. dominica or S. oryzae. The toxicity of spinosad to each species varied slightly among the three commodities, and there were no consistent trends to suggest that spinosad was more effective on one commodity versus another. LT50 values based on immediate mortality for R. dominica on all commodities ranged from 0.45 to 0.74 d; corresponding values based on delayed mortality ranged from 0.04 to 0.23 d, suggesting delayed toxic action of spinosad in R. dominica. LT50 values based on immediate and delayed mortality for S. oryzae on all three commodities treated with the two spinosad formulations were essentially similar and ranged from 2.75 to 4.56 d. LT95 values for R. dominica based on immediate mortality on spinosad-treated commodities ranged from 1.75 to 3.36 d, and those based on delayed mortality ranged from 0.49 to 1.88 d. There were no significant differences in

  10. Quantum radiation from an inertial scalar charge evolving in the de Sitter universe: Weak-field limit

    SciTech Connect

    Blaga, Robert

    2015-12-07

    We investigate the energy radiated by an inertial scalar charge evolving in the expanding Poincaré patch of de Sitter spacetime, in the framework of scalar QED perturbation theory. We approximate the transition amplitude in the small expansion parameter limit and show that the leading contribution to the radiated energy has the form of the energy radiated by an accelerated particle in Minkowski space.

  11. Cage study of spinosad-based bait efficacy on Bactrocera cucurbitae, Dacus ciliatus, and Dacus demmerezi (Diptera: Tephritidae) in Reunion Island.

    PubMed

    Deguine, Jean-Philippe; Douraguia, Elisabeth; Atiama-Nurbel, Toulassi; Chiroleu, Fréderic; Quilici, Serge

    2012-08-01

    On Reunion Island, Bactrocera cucurbitae (Coquillett), Dacus ciliatus (Loew), and Dacus demmerezi (Bezzi) cause severe damage to Cucurbit crops. The aim of the study was to test in field cages the effectiveness of Synéis-appât (Dow AgroSciences), a spinosad-based bait (0.02% of spinosad) on both attraction and mortality of young adults (6-9 d old) of these three species. The effects of gender were also evaluated for all species whereas the effects of protein deprivation were tested with B. cucurbitae only. For the first 15 min after application, significantly more B. cucurbitae adults (21.7 +/- 1.8%) were attracted to the bait than D. demmerezi (7.6 +/- 2.4%) and D. ciliatus (2.7 +/- 1.4%); the subsequent response (30-75 min after bait application) of D. demmerezi was statistically similar to that recorded for B. cucurbitae; whereas the response ofD. ciliatus to the bait was consistently significantly lower. Adult mortality was significantly higher for B. cucurbitae (94.6 +/- 0.7%) than for D. demmerezi (85.7 +/- 2.1%), and was significantly higher for the latter than for D. ciliatus (60.4 +/- 4.4%). Sex had no significant effect on the mortality rate for each species. The efficiency of the bait was the same for B. cucurbitae adults regardless whether or not the diet included proteins. Overall, Synéis-appât appears to be more effective against B. cucurbitae and B. demmerezi than against D. ciliatus. In Reunion Island, this bait could constitute a useful component in the framework of Integrated Pest Management.

  12. Analysis of persistent changes to γ-aminobutyric acid receptor gene expression in Plutella xylostella subjected to sublethal amounts of spinosad.

    PubMed

    Yin, X-H; Wu, Q-J; Zhang, Y-J; Long, Y-H; Wu, X-M; Li, R-Y; Wang, M; Tian, X-L; Jiao, X-G

    2016-01-01

    A multi-generational approach was used to investigate the persistent effects of a sub-lethal dose of spinosad in Plutella xylostella. The susceptibility of various sub-populations of P. xylostella to spinosad and the effects of the insecticide on the gene expression of γ-aminobutyric acid receptor (GABAR) were determined. The results of a leaf dip bioassay showed that the sensitivity of P. xylostella to spinosad decreased across generations. The sub-strains had been previously selected based on a determined LC25 of spinosad. Considering that GABA-gated chloride channels are the primary targets of spinosad, the cDNA of P. xylostella was used to clone GABARα by using reverse transcription-polymerase chain reaction (RT-PCR). The mature peptide cDNA was 1477-bp long and contained a 1449-bp open reading frame encoding a protein of 483 amino acids. The resulting amino acid sequence was used to generate a neighbor-joining dendrogram, and homology search was conducted using NCBI BLAST. The protein had high similarity with the known GABAR sequence from P. xylostella. Subsequent semi-quantitative RT-PCR and real-time PCR analyses indicated that the GABAR transcript levels in the spinosad-resistant strain (RR, 145.82-fold) and in Sub1 strain (selected with LC25 spinosad for one generation) were the highest, followed by those in the spinosad-susceptible strain, the Sub10 strain (selected for ten generations), and the Sub5 strain (selected for five generations). This multi-generational study found significant correlations between spinosad susceptibility and GABAR gene expression, providing insights into the long-term effects of sub-lethal insecticide exposure and its potential to lead to the development of insecticide-resistant insect populations. PMID:27525859

  13. Efficacy of Spinosad Tablets Administered to a Colony of 15 Indoor Cats Naturally Infested with Fleas

    PubMed Central

    Cadiergues, Marie-Christine; Pressanti, Charline

    2014-01-01

    The aims of the study were (i) to describe adult fleas distribution in a strictly indoor cat colony composed of cats with flea allergy dermatitis (FAD) and non-FAD cats and (ii) to evaluate the efficacy of spinosad used alone. Skin lesions were scored according to the SCORing Feline Allergic Dermatitis lesion severity scale (SCORFAD) on days 0, 15, 30, 45, 60, and 90. Cats were combed prior to the treatment (days 0, 30, and 60) and on days 15, 45, and 90; collected fleas were replaced on the animals. All cats received flavored spinosad tablets (Comfortis) at a dosage of 50–75 mg/kg on days 0, 30, and 60. Cats were fed immediately afterwards. On day 0, a total of 60 fleas were collected (mean: 4 ± 4). Cats with FAD had a SCORFAD of 6, 8, 12, and 13 and harbored 0, 2, 1, and 0 fleas, respectively. Tablets were taken voluntarily by 8, 11, and 12 cats on days 0, 30, and 60, respectively. No adverse event was recorded. From day 15 to day 90, no fleas could be collected. SCORFAD was reduced by 40%, 71%, 80%, 89%, and 98% on days 15, 30, 45, 60, and 90, respectively. PMID:24977046

  14. Evolving force-free magnetic fields. III - States of nonequilibrium and the preflare stage. [in solar atmosphere

    NASA Technical Reports Server (NTRS)

    Low, B. C.

    1980-01-01

    The paper considers whether a neighboring magnetostatic equilibrium exists to allow a magnetic field initially in a force-free configuration to accommodate any imposed weak pressure. The following problem is treated. The foot points of the field are fixed and the plasma is frozen into the field lines under the approximation of infinite electrical conductivity. A weak pressure is introduced. It is determined infinitesimal plasma displacements exist to adjust the field lines to a new equilibrium without changing the field line connectivity. The analysis is carried out for the bipolar force-free fields forming one of two evolutionary sequences modeling the development of the preflare stage. It was found that for the force-free field corresponding to the quasi-static stage of evolution, the neighboring magnetostatic equilibrium always exists and the imposed gas pressure can be accommodated with a slight departure of the field from being exactly force free.

  15. Toxicity and feeding response of adult corn earworm (Lepidoptera: Noctuidae) to an organic spinosad formulation in sucrose solution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult corn earworm, Helicoverpa zea (Boddie), feeds on plant exudates soon after emergence from pupa in their natural habitat, and thereafter disperses to suitable host plants for reproduction. The intent of this study was to determine if Entrust™, an organic formulation of spinosad, could be used i...

  16. Sucrose mixed with spinosad enhances kill and reduces oviposition of Rhagoletis indifferens (Diptera: Tephritidae) under low-food conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Whether sugar mixed with insecticides enhances kill of western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), may depend on insecticide rate and food availability. Here, the hypothesis that sucrose mixed with the insecticide spinosad (in the Entrust® SC formulation) enhance...

  17. Mortality of Rhagoletis indifferens exposed to hydrolyzed protein baits and spinosad in the absence and presence of yeast extract

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Western cherry fruit fly, Rhagoletis indifferens Curran, is the major quarantine pest of sweet cherry, Prunus avium L. (L.), in the Pacific Northwest of the USA and in British Columbia in Canada. Although spinosad bait (GF-120 NF Naturalyte® Fruit Fly Bait, Dow AgroSciences, Indianapolis, IN, USA) ...

  18. Attraction and Mortality of Oriental Fruit Flies (Diptera: Tephritidae) to SPLAT-MAT- Methyl Eugenol with Spinosad

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted in Hawaii to quantify attraction and feeding responses resulting in mortality of male oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), to SPLAT-MAT-methyl eugenol (ME) with spinosad in comparison with Min-U-Gel-ME with naled (Dibrom). Our approach invol...

  19. Temperature-mediated kill and oviposition of Western Cherry Fruit Fly (Diptera: Tephritidae) in the presence of Spinosad

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), is a quarantine pest of sweet cherry (Prunus avium (L.) L.) that is managed using insecticides, including spinosad, an organic compound that can be applied in low spray volumes. Identifying factors that can increase the...

  20. Truncated transcripts of nicotinic acetylcholine subunit gene bdalpha6 are associated with spinosad resistance in Bactrocera dorsalis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated spinosad resistance mechanisms of a Bactocera dorsalis strain from Taiwan. Resistance levels were 901-fold, and there was no cross resistance against imidacloprid or fipronil Combined biochemical and synergistic data indicated that target site insensitivity is the major resistance co...

  1. Determination of the mineral stability field of evolving groundwater in the Lake Bosumtwi impact crater and surrounding areas

    NASA Astrophysics Data System (ADS)

    Loh, Yvonne Sena Akosua; Yidana, Sandow Mark; Banoeng-Yakubo, Bruce; Sakyi, Patrick Asamoah; Addai, Millicent Obeng; Asiedu, Daniel Kwadwo

    2016-09-01

    Conventional graphical techniques, mass balance geochemical modelling, and multivariate statistical methods were jointly applied to hydrogeochemical data of groundwater from the fractured rock aquifer system, and surface water in the Bosumtwi and surrounding areas to reveal evolutionary trends and the characteristics of evolving groundwater in the area. Four clusters distinguished from the Q-mode hierarchical cluster analysis (HCA) comprised three main groundwater associations and one surface water group (lake water). Although both water resources are of low mineralization (TDS < 1000 mg/l), it was observed that the groundwater from the upper catchment with hydrochemical facies dominated by Nasbnd Mgsbnd HCO3-, evolves to Casbnd Mgsbnd and mixed cations HCO3- water types at the lower reaches. The lake water on the other hand is Nasbnd HCO3- water type. Results from principal component analyses (PCA) and other geochemical interpretations distinguished three sources of variations in the hydrochemistry. Saturation indices of possible reactive mineral phases show groundwater undersaturation relative to albite, anorthite, aragonite, barite, calcite, chlorite, chrysotile, dolomite, gypsum, k-felspar and talc, and supersaturation with respect to gibbsite, kaolinite, Ca-montmorillonite and k-mica in the area. The PCA and other geochemical interpretation identify weathering of feldspars and carbonate mineral dissolution as predominantly influencing the hydrochemistry of the groundwater. Hydrolysis of the aluminosilicates causes the groundwater to reach equilibrium with kaolinite. In addition to dissolution of silicates, the chemical composition of the lake water has been influenced by evaporation and consequent carbonate saturation.

  2. Current-density functional theory study of the H2 molecule evolving under a strong ultrashort magnetic field

    NASA Astrophysics Data System (ADS)

    Vikas, Hash(0xb7f6e60)

    2012-01-01

    Hydrogen molecule in a strong ultrashort magnetic field is investigated through a current-density functional theory (CDFT) and quantum fluid dynamics (QFD) based approach employing current-density dependent vector exchange-correlation potential and energy density functional derived with a vorticity variable. The numerical computations through the CDFT based approach are performed for the H2 molecule, starting initially from its field-free ground state, in a parallel internuclear axis and magnetic field-axis configuration with the internuclear separation R ranging from 0.1 a.u. to 14.0 a.u., and the strength of the time-dependent (TD) magnetic field varying between 0-1011 G over a few femtoseconds. The numerical results are compared with that obtained using an approach based on the current-density independent approximation under similar computational constraints but employing only scalar exchange-correlation potential dependent on the electronic charge-density alone. The current-density based approach yields exchange- and correlation energy as well as electronic charge-density of the H2 molecule drastically different from that obtained using current-independent approach, in particular, at TD magnetic field-strengths >109 G during a typical time-period of the field when the magnetic-field had attained maximum applied field-strength and is switched to a decreasing ramp function. This nonadiabatic behavior of the TD electronic charge-density is traced to the TD vorticity-dependent vector exchange-correlation potential of the CDFT based approach. The interesting electron dynamics of the H2 molecule in strong TD magnetic field is further elucidated by treating electronic charge-density as an `electron-fluid'. The present work also reveals interesting real-time dynamics on the attosecond time-scale in the electronic charge-density distribution of the hydrogen molecule.

  3. Evolving Complex Networks Analysis of Space-Time Multi-Scale Wavelike Fields: Application to African Rainfall Dynamics

    NASA Astrophysics Data System (ADS)

    Oluoch, Kevin; Marwan, Norbert; Trauth, Martin; Kurths, Juergen

    2013-04-01

    Evolving complex networks analysis is a very recent and very promising attempt to describe, in the most realistic ways, complex systems or multi-system dynamics. The Earth system is comprised of many attractors that are multi-scaled, multi-complexity non-linear systems of systems. Space time propagations responsible for precipitation is one example in which the interactions between the aforementioned properties of complex systems can be applied; especially the spatio-temporal wave likeness of spatial patterning and temporal recurrences representative of the underlying dynamics. Tobler's first law of geography states: "Everything is related to everything else, but near things are more related than distant things" (Waldo Tobler, 1970 Economic Geography 46: 234-40). Most time-series analysis are pairwise correlations and even when faced with gridded data, the neighborhood characteristics is never used as an input variable. In our point of view, such analysis ignore vital information on the multi-scale non-linear spatial patterns of the continuities and singularities possibly resulting from underlying random processes. This work in progress is an application, mainly inspired by wave theory and non-linear dynamics. It is a systematic method of methods, which exploits the nonlinear multi-scale wave nature of virtually everything in nature including financial data, disease dynamics et cetera and applies it to climate through complex network analysis of rainfall data. The method uses a continuous spatial wavelet transform for non-linear multi-scale decomposition. Such an output carries all vital information pertaining the singularity structures in the data. Similarity measures are obtained by considering the multi-fractal nature of the distribution of discontinuities. The more similar the point-wise generalized dimensions are in-terms of their continuity, fractal, entropy, information and correlation dimensions, the higher the chance that they characterize similar

  4. A ligand field chemistry of oxygen generation by the oxygen-evolving complex and synthetic active sites

    PubMed Central

    Betley, Theodore A; Surendranath, Yogesh; Childress, Montana V; Alliger, Glen E; Fu, Ross; Cummins, Christopher C; Nocera, Daniel G

    2007-01-01

    Oxygen–oxygen bond formation and O2 generation occur from the S4 state of the oxygen-evolving complex (OEC). Several mechanistic possibilities have been proposed for water oxidation, depending on the formal oxidation state of the Mn atoms. All fall under two general classifications: the AB mechanism in which nucleophilic oxygen (base, B) attacks electrophilic oxygen (acid, A) of the Mn4Ca cluster or the RC mechanism in which radical-like oxygen species couple within OEC. The critical intermediate in either mechanism involves a metal oxo, though the nature of this oxo for AB and RC mechanisms is disparate. In the case of the AB mechanism, assembly of an even-electron count, high-valent metal-oxo proximate to a hydroxide is needed whereas, in an RC mechanism, two odd-electron count, high-valent metal oxos are required. Thus the two mechanisms give rise to very different design criteria for functional models of the OEC active site. This discussion presents the electron counts and ligand geometries that support metal oxos for AB and RC O–O bond-forming reactions. The construction of architectures that bring two oxygen functionalities together under the purview of the AB and RC scenarios are described. PMID:17971328

  5. Spinosad Topical

    MedlinePlus

    ... suspension is used to treat head lice (small insects that attach themselves to the skin) in adults ... ask your doctor or pharmacist to explain any part you do not understand. Use ... over the rest of your body. You and anyone who helped you apply the ...

  6. Chemical abundances and kinematics of 257 G-, K-type field giants. Setting a base for further analysis of giant-planet properties orbiting evolved stars

    NASA Astrophysics Data System (ADS)

    Adibekyan, V. Zh.; Benamati, L.; Santos, N. C.; Alves, S.; Lovis, C.; Udry, S.; Israelian, G.; Sousa, S. G.; Tsantaki, M.; Mortier, A.; Sozzetti, A.; De Medeiros, J. R.

    2015-06-01

    We performed a uniform and detailed abundance analysis of 12 refractory elements (Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Co, Sc, Mn, and V) for a sample of 257 G- and K-type evolved stars from the CORALIE planet search programme. To date, only one of these stars is known to harbour a planetary companion. We aimed to characterize this large sample of evolved stars in terms of chemical abundances and kinematics, thus setting a solid base for further analysis of planetary properties around giant stars. This sample, being homogeneously analysed, can be used as a comparison sample for other planet-related studies, as well as for different type of studies related to stellar and Galaxy astrophysics. The abundances of the chemical elements were determined using an local thermodynamic equilibrium (LTE) abundance analysis relative to the Sun, with the spectral synthesis code MOOG and a grid of Kurucz ATLAS9 atmospheres. To separate the Galactic stellar populations, both a purely kinematical approach and a chemical method were applied. We confirm the overabundance of Na in giant stars compared to the field FGK dwarfs. This enhancement might have a stellar evolutionary character, but departures from LTE may also produce a similar enhancement. Our chemical separation of stellar populations also suggests a `gap' in metallicity between the thick-disc and high-α metal-rich stars, as previously observed in dwarfs sample from HARPS. The present sample, as most of the giant star samples, also suffers from the B - V colour cut-off, which excludes low-log g stars with high metallicities, and high-log g star with low [Fe/H]. For future studies of planet occurrence dependence on stellar metallicity around these evolved stars, we suggest to use a subsample of stars in a `cut-rectangle' in the log g-[Fe/H] diagram to overcome the aforementioned issue.

  7. Disgust: Evolved Function and Structure

    ERIC Educational Resources Information Center

    Tybur, Joshua M.; Lieberman, Debra; Kurzban, Robert; DeScioli, Peter

    2013-01-01

    Interest in and research on disgust has surged over the past few decades. The field, however, still lacks a coherent theoretical framework for understanding the evolved function or functions of disgust. Here we present such a framework, emphasizing 2 levels of analysis: that of evolved function and that of information processing. Although there is…

  8. The Pu'u 'O'o Eruption: Space-Borne Remote Sensing of the Evolving Lava Flow Field

    NASA Astrophysics Data System (ADS)

    Flynn, L. P.; Harris, A. J.; Mouginis-Mark, P. J.; Geschwind, L. R.; Rowland, S. K.; Horton, K. A.

    2002-12-01

    Volcanic eruptions provide excellent targets for remote sensing platforms designed to monitor surface change. The Pu'u 'O'o eruption has been ongoing during a remarkable period of technological advance in satellite instruments developed by NASA, ESA, and NASDA. Here, we divide instruments into three groups based on their spatial/temporal resolution and spectral data collection capabilities. Group 1 includes the Landsat family of satellites that have been providing multi-spectral (visible-IR) images at 30 m spatial resolution once every 16 days since the launch of Landsat 1 in 1972. Since 1991, we have used Landsats 4, 5, and 7 and the ASTER instrument to map the active lava flow field during the various phases of the Pu'u 'O'o eruption and to calculate effusion rates over the entire flow field. Maps of radiative energy have been created that highlight actively expanding versus cooling lava flow pads. The Earth Observing-1 satellite, launched in November, 2000, carries the hyperspectral Hyperion instrument that has 30 m per pixel spatial resolution. Offering 220 spectral bands at 0.4 - 2.5 microns, Hyperion data are used to calculate multiple radiative thermal components from lava surfaces at different temperatures and thus provides better estimates of effusion rates. Group 2 includes NOAA's GOES and NASA's MODIS series instruments that offer higher temporal resolution data (images every 15 minutes - 1 day) for hazard monitoring, but lower spatial resolution data (0.25 -4 km/pixel). We have used GOES data to track the start and stop times of eruptions. We have used MODIS data to provide detailed daily flow maps of the eruptions. MODIS and MISR data can also be used to track the downwind dispersal of the volcanic aerosol plume. The GOES and MODIS data streams are also used in near-real-time operational hazard monitoring web-based information systems. Group 3 includes imaging radar systems (JERS-1, SIR-C, ERS and RADARSAT) that use interferometry to investigate the

  9. Evidence of Field-Evolved Resistance to Bifenthrin in Western Corn Rootworm (Diabrotica virgifera virgifera LeConte) Populations in Western Nebraska and Kansas

    PubMed Central

    Pereira, Adriano E.; Wang, Haichuan; Zukoff, Sarah N.; Meinke, Lance J.; French, B. Wade; Siegfried, Blair D.

    2015-01-01

    Pyrethroid insecticides have been used to control larvae or adults of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, a key pest of field corn in the United States. In response to reports of reduced efficacy of pyrethroids in WCR management programs in southwestern areas of Nebraska and Kansas the present research was designed to establish a baseline of susceptibility to the pyrethroid insecticide, bifenthrin, using susceptible laboratory populations and to compare this baseline with susceptibility of field populations. Concentration-response bioassays were performed to estimate the baseline susceptibility. From the baseline data, a diagnostic concentration (LC99) was determined and used to test adults of both laboratory and field populations. Larval susceptibility was also tested using both laboratory and field populations. Significant differences were recorded in adult and larval susceptibility among WCR field and laboratory populations. The highest LC50 for WCR adults was observed in populations from Keith 2 and Chase Counties, NE, with LC50s of 2.2 and 1.38 μg/vial, respectively, and Finney County 1, KS, with 1.43 μg/vial, as compared to a laboratory non-diapause population (0.24 μg/vial). For larvae, significant differences between WCR field and laboratory populations were also recorded. Significant differences in mortalities at the diagnostic bifenthrin concentration (LC99) were observed among WCR adult populations with western Corn Belt populations exhibiting lower susceptibility to bifenthrin, especially in southwestern Nebraska and southwestern Kansas. This study provides evidence that resistance to bifenthrin is evolving in field populations that have been exposed for multiple years to pyrethroid insecticides. Implications to sustainable rootworm management are discussed. PMID:26566127

  10. How simple autonomous decisions evolve into robust behaviours? A review from neurorobotics, cognitive, self-organized and artificial immune systems fields.

    PubMed

    Fernandez-Leon, Jose A; Acosta, Gerardo G; Rozenfeld, Alejandro

    2014-10-01

    Researchers in diverse fields, such as in neuroscience, systems biology and autonomous robotics, have been intrigued by the origin and mechanisms for biological robustness. Darwinian evolution, in general, has suggested that adaptive mechanisms as a way of reaching robustness, could evolve by natural selection acting successively on numerous heritable variations. However, is this understanding enough for realizing how biological systems remain robust during their interactions with the surroundings? Here, we describe selected studies of bio-inspired systems that show behavioral robustness. From neurorobotics, cognitive, self-organizing and artificial immune system perspectives, our discussions focus mainly on how robust behaviors evolve or emerge in these systems, having the capacity of interacting with their surroundings. These descriptions are twofold. Initially, we introduce examples from autonomous robotics to illustrate how the process of designing robust control can be idealized in complex environments for autonomous navigation in terrain and underwater vehicles. We also include descriptions of bio-inspired self-organizing systems. Then, we introduce other studies that contextualize experimental evolution with simulated organisms and physical robots to exemplify how the process of natural selection can lead to the evolution of robustness by means of adaptive behaviors.

  11. Assessing five evolving microbial enzyme models against field measurements from a semiarid savannah—What are the mechanisms of soil respiration pulses?

    NASA Astrophysics Data System (ADS)

    Zhang, Xia; Niu, Guo-Yue; Elshall, Ahmed S.; Ye, Ming; Barron-Gafford, Greg A.; Pavao-Zuckerman, Mitch

    2014-09-01

    Soil microbial respiration pulses in response to episodic rainfall pulses (the "Birch effect") are poorly understood. We developed and assessed five evolving microbial enzyme models against field measurements from a semiarid savannah characterized by pulsed precipitation to understand the mechanisms to generate the Birch pulses. The five models evolve from an existing four-carbon (C) pool model to models with additional C pools and explicit representations of soil moisture controls on C degradation and microbial uptake rates. Assessing the models using techniques of model selection and model averaging suggests that models with additional C pools for accumulation of degraded C in the dry zone of the soil pore space result in a higher probability of reproducing the observed Birch pulses. Degraded C accumulated in dry soil pores during dry periods becomes immediately accessible to microbes in response to rainstorms, providing a major mechanism to generate respiration pulses. Explicitly representing the transition of degraded C and enzymes between dry and wet soil pores in response to soil moisture changes and soil moisture controls on C degradation and microbial uptake rates improve the models' efficiency and robustness in simulating the Birch effect. Assuming that enzymes in the dry soil pores facilitate degradation of complex C during dry periods (though at a lower rate) results in a greater accumulation of degraded C and thus further improves the models' performance. However, the actual mechanism inducing the greater accumulation of labile C needs further experimental studies.

  12. Genomic instability induced by 50Hz magnetic fields is a dynamically evolving process not blocked by antioxidant treatment.

    PubMed

    Kesari, Kavindra Kumar; Luukkonen, Jukka; Juutilainen, Jukka; Naarala, Jonne

    2015-12-01

    Increased level of micronuclei was observed in SH-SY5Y cells in a previous study at 8 and 15 days after exposure to extremely low frequency (ELF) magnetic fields (MF), indicating possible induction of genomic instability in the progeny of the exposed cells. The aim of this study was to further explore the induction of genomic instability by ELF MFs by increasing the follow-up time up to 45 days after exposure. Human SH-SY5Y neuroblastoma cells were exposed to a 50Hz, 100μT MF for 24h with or without co-exposure to menadione (MQ), a chemical agent that increases cellular superoxide production. Micronuclei, reactive oxygen species (ROS) and lipid peroxidation (LPO) were measured at 15, 30 and 45 days after exposure. To study the possible causal role of ROS in the delayed effects of MF, the antioxidant N-acetylcysteine (NAC) was administered before MF exposure. Consistently with the previous study, the level of micronuclei was statistically significantly elevated 15 days after exposure. A similar effect was observed at 30 days, but not at 45 days after exposure. The level of LPO was statically significantly decreased 30 and 45 days after exposure. Consistently with our previous findings, the MF effect did not depend on co-exposure to MQ. Treatment with NAC effectively decreased cellular ROS level and suppressed the effect of MQ on ROS, but it did not block the MF effect, indicating that increase in ROS is not needed as a causal link between MF exposure and induction of delayed effects. The results presented here are consistent with genomic instability that persists in the progeny of MF-exposed cells up to at least 30 days after exposure. Changes in LPO observed at 30 and 45 days after exposure indicates that the MF-initiated process may continue up to at least 45 days after exposure. PMID:26653983

  13. A three amino acid deletion in the transmembrane domain of the nicotinic acetylcholine receptor α6 subunit confers high-level resistance to spinosad in Plutella xylostella

    PubMed Central

    Wang, Jing; Wang, Xingliang; Lansdell, Stuart J.; Zhang, Jianheng; Millar, Neil S.; Wu, Yidong

    2016-01-01

    Spinosad is a macrocyclic lactone insecticide that acts primarily at the nicotinic acetylcholine receptors (nAChRs) of target insects. Here we describe evidence that high levels of resistance to spinosad in the diamondback moth (Plutella xylostella) are associated with a three amino acid (3-aa) deletion in the fourth transmembrane domain (TM4) of the nAChR α6 subunit (Pxα6). Following laboratory selection with spinosad, the SZ-SpinR strain of P. xylostella exhibited 940-fold resistance to spinosad. In addition, the selected insect population had 1060-fold cross-resistance to spinetoram but, in contrast, no cross-resistance to abamectin was observed. Genetic analysis indicates that spinosad resistance in SZ-SpinR is inherited as a recessive and autosomal trait, and that the 3-aa deletion (IIA) in TM4 of Pxα6 is tightly linked to spinosad resistance. Because of well-established difficulties in functional expression of cloned insect nAChRs, the analogous resistance-associated deletion mutation was introduced into a prototype nAChR (the cloned human α7 subunit). Two-electrode voltage-clamp recording with wild-type and mutated nAChRs expressed in Xenopus laevis oocytes indicated that the mutation causes a complete loss of agonist activation. In addition, radioligand binding studies indicated that the 3-aa deletion resulted in significantly lower-affinity binding of the extracellular neurotransmitter-binding site. These findings are consistent with the 3-amino acid (IIA) deletion within the transmembrane domain of Pxα6 being responsible for target-site resistance to spinosad in the SZ-SpinR strain of P. xylostella. PMID:26855198

  14. A comparative assessment of the response of three fruit fly species (Diptera: Tephritidae) to a spinosad-based bait: effect of ammonium acetate, female age, and protein hunger.

    PubMed

    Piñero, J C; Mau, R F L; Vargas, R I

    2011-08-01

    Ammonia-releasing substances are known to play an important role in fruit fly (Diptera: Tephritidae) attraction to food sources, and this information has been exploited for the development of effective synthetic food-based lures and insecticidal baits. In field studies conducted in Hawaii, we examined the behavioural response of wild female oriental fruit fly (Bactrocera dorsalis (Hendel)), melon fly (B. cucurbitae (Coquillett)), and Mediterranean fruit fly (Ceratitis capitata (Wiedemann)) to spinosad-based GF-120 NF Naturalyte Fruit Fly Bait(©) formulated to contain either 0, 1 or 2% ammonium acetate. Use of visually-attractive yellow bait stations for bait application in the field allowed for proper comparisons among bait formulations. Field cage tests were also conducted to investigate, using a comparative behavioural approach, the effects of female age and protein starvation on the subsequent response of F1 generation B. cucurbitae and B. dorsalis to the same three bait formulations that were evaluated in the field. Our field results indicate a significant positive effect of the presence, regardless of amount, of AA in GF-120 for B. dorsalis and B. cucurbitae. For C. capitata, there was a significant positive linear relationship between the relative amounts of AA in bait and female response. GF-120 with no AA was significantly more attractive to female C. capitata, but not to female B. dorsalis or B. cucurbitae, than the control treatment. Our field cage results indicate that the effects of varying amounts of AA present in GF-120 can be modulated by the physiological stage of the female flies and that the response of female B. cucurbitae to GF-120 was consistently greater than that of B. dorsalis over the various ages and levels of protein starvation regimes evaluated. Results are discussed in light of their applications for effective fruit fly suppression.

  15. Preliminary study on the acaricidal efficacy of spinosad administered orally to dogs infested with the brown dog tick, Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae).

    PubMed

    Snyder, Daniel E; Cruthers, Larry R; Slone, Robyn L

    2009-12-01

    Spinosad is a novel mode of action insecticide and acaricide derived from a family of natural compounds produced from fermentation of the actinomycete, Saccharopolyspora spinosa. Although spinosad has been shown to have rapid knockdown and 1 month of residual efficacy against fleas (Ctenocephalides spp.) following oral administration in dogs, potential activity against ticks infesting dogs has not been determined. To address this possibility, a proof-of-concept laboratory efficacy study was conducted using dogs orally treated with spinosad and experimentally infested with the brown dog tick, Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae). In this randomized block (blocked by gender and pre-treatment tick counts), blinded, parallel-arm study, 12 dogs selected on health and ability to maintain pre-treatment tick populations were allocated equally among three groups: placebo-treated negative control, and spinosad in gelatin capsules at 50 and 100mg/kg administered per os. All treatments were administered once on Day 0. On days -6, -1, 7, 14, 21 and 28, each dog was infested with 50 unfed adult R. sanguineus, approximately 50% male and 50% female, obtained from the investigator's established tick colony. Tick comb counts were performed approximately 48 h post-infestation by study personnel who were blinded to treatments. Compared to geometric mean live tick counts in the control group, tick counts in the 50 and 100mg/kg spinosad doses were significantly (P<0.05) reduced by 94.8 and 97.2%, respectively, within 24h of treatment. Compared to geometric mean live tick counts in the control group at Days 9, 16, 23 and 30 after treatment, the 50mg/kg spinosad treatment group demonstrated 67.8, 49.1, 52.1 and 5.0% reductions, while the 100mg/kg spinosad treatment group demonstrated 88.6, 70.6, 61.9 and 71.3% reductions, respectively. This pilot efficacy study demonstrated that a single oral treatment with technical spinosad in gelatin capsules, at 50 and 100mg

  16. The Effect of Application Rate of GF-120 (Spinosad) and Malathion on the Mortality of Apis mellifera (Hymenoptera: Apidae) Foragers.

    PubMed

    Cabrera-Marín, Nina Vanessa; Liedo, Pablo; Sánchez, Daniel

    2016-04-01

    Beneficial organisms like the honey bee, Apis mellifera L. (Hymenoptera: Apidae), are heavily affected by pest control practices that incorporate insecticides. Safer alternatives as the spinosad-based formulation GF-120 have been developed to overcome this issue. Though both the low concentration of spinosad and the ultra-low-volume application rate of GF-120 are supposed to have a low acute toxicity in honey bee foragers, to our knowledge such claims have not been explicitly proven. We thus carried out a series of experiments to assess the effect of GF-120, malathion, and Spintor (spinosad) on honey bee foragers when applied at two concentrations (80 and 1,500 ppm) and two application rates (low density rate [LDR]—80 drops of 5 mm diameter per square meter; high density rate [HDR]—thousands of 200 -µm-diameter droplets per square meter). Interestingly, the three pesticides caused low mortality on foragers when applied at LDR-80, LDR-1,500, or HDR-80. However, HDR-1,500 caused a very high mortality. Based upon these results, we developed a computer program to estimate the average number of foragers that are exposed at LDR and HDR. We found that more foragers receive a lethal dose when exposed at HDR than at the other rates. Our results support the hypothesis that the impact of GF-120 and malathion upon honey bees is minimal when applied at LDR and that computer simulation can help greatly in understanding the effects of pesticides upon nontarget species. PMID:26739308

  17. Color and Stellar Population Gradients in Passively Evolving Galaxies at z ~ 2 from HST/WFC3 Deep Imaging in the Hubble Ultra Deep Field

    NASA Astrophysics Data System (ADS)

    Guo, Yicheng; Giavalisco, Mauro; Cassata, Paolo; Ferguson, Henry C.; Dickinson, Mark; Renzini, Alvio; Koekemoer, Anton; Grogin, Norman A.; Papovich, Casey; Tundo, Elena; Fontana, Adriano; Lotz, Jennifer M.; Salimbeni, Sara

    2011-07-01

    We report the detection of color gradients in six massive (stellar mass (M star) > 1010 M ⊙) and passively evolving (specific star formation rate <10-11 yr-1) galaxies at redshift 1.3 < z < 2.5 identified in the Hubble Ultra Deep Field using ultra-deep Hubble Space Telescope (HST) Advanced Camera for Surveys and WFC3/IR images. After carefully matching the different point-spread functions, we obtain color maps and multi-band optical/near-IR photometry (BVizYJH) in concentric annuli, from the smallest resolved radial distance (≈1.7 kpc) up to several times the H-band effective radius. We find that the inner regions of these galaxies have redder rest-frame UV-optical colors (U - V, U - B, and B - V) than the outer parts. The slopes of the color gradient have no obvious dependence on the redshift and on the stellar mass of the galaxies. They do mildly depend, however, on the overall dust obscuration (E(B - V)) and rest-frame (U - V) color, with more obscured or redder galaxies having steeper color gradients. The z ~ 2 color gradients are also steeper than those of local early-type ones. The gradient of a single parameter (age, extinction, or metallicity) cannot fully explain the observed color gradients. Fitting the spatially resolved HST seven-band photometry to stellar population synthesis models, we find that, regardless of assumptions on the metallicity gradient, the redder inner regions of the galaxies have slightly higher dust obscuration than the bluer outer regions, implying that dust partly contributes to the observed color gradients, although the magnitude depends on the assumed extinction law. Due to the age-metallicity degeneracy, the derived age gradient depends on the assumptions for the metallicity gradient. We discuss the implications of a number of assumptions for metallicity gradients on the formation and evolution of these galaxies. We find that the evolution of the mass-size relationship from z ~ 2 to the present cannot be driven by in situ

  18. Evolvable synthetic neural system

    NASA Technical Reports Server (NTRS)

    Curtis, Steven A. (Inventor)

    2009-01-01

    An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

  19. Dose confirmation and non-interference evaluations of the oral efficacy of a combination of milbemycin oxime and spinosad against the dose limiting parasites, adult cat flea (Ctenocephalides felis) and hookworm (Ancylostoma caninum), in dogs.

    PubMed

    Snyder, Daniel E; Wiseman, Scott

    2012-03-23

    Two separate controlled and blinded studies were conducted to confirm the dose and non-interference of spinosad and milbemycin oxime (MO) administered orally in combination or alone to dogs for the treatment and control of experimentally induced flea infestations (Ctenocephalides felis) and adult hookworm infections (Ancylostoma caninum). For each study, dogs were allocated randomly based on pre-treatment adult flea and hookworm egg counts to one of four treatment groups of 10 animals each. In each study, spinosad and MO in combination, using the lower half (30-45 mg/kg spinosad; 0.5-0.75 mg/kg MO) of the US commercial dose band (30-60 mg/kg spinosad; 0.5-1.0mg/kg MO) of each active ingredient, or individually alone using the full dose range, were given orally to dogs on Day 0 using a tablet formulation. A placebo control was treated similarly. In one study, on Days -1, 5, 12, 19, 28 and 35 each dog was infested with approximately 100 unfed adult C. felis obtained from the investigator's established flea colony. All dogs were infested via the same method. Forty-eight hour post-infestation flea comb counts were conducted on Days 1, 7, 14, 21, 30 and 37 and were used to determine the knockdown and residual flea activity. In the second study, on Day -27 each of 48 dogs were experimentally inoculated with 100 third-stage infective larvae of the hookworm, A. caninum. Dogs were treated on Day 0 and necropsied on Day 7 or Day 8. All nematodes in the intestinal tract were collected on Day 7 or Day 8, identified and counted by species and stage. Post-treatment, the geometric mean live flea counts were significantly different (p-value<0.0001) between the spinosad/MO combination and the spinosad only treatment groups as compared to the vehicle control group. The flea counts in the MO only group and the control group were not statistically different. The spinosad and MO combination group and the spinosad only treatment group demonstrated significantly different knockdown (100

  20. Field Characterization of the Mineralogy and Organic Chemistry of Carbonates from the 2010 Arctic Mars Analog Svalbard Expedition by Evolved Gas Analysis

    NASA Technical Reports Server (NTRS)

    McAdam, A. C.; Ten Kate, I. L.; Stern, J. C.; Mahaffy, P. R.; Blake, D. F.; Morris, R. V.; Steele, A.; Amundson, H. E. F.

    2011-01-01

    The 2010 Arctic Mars Analog Svalbard Expedition (AMASE) investigated two geologic settings using methodologies and techniques being developed or considered for future Mars missions, such as the Mars Science Laboratory (MSL), ExoMars, and Mars Sample Return. The Sample Analysis at Mars (SAM) [1] instrument suite, which will be on MSL, consists of a quadrupole mass spectrometer (QMS), a gas chromatograph (GC), and a tunable laser mass spectrometer (TLS); all will be applied to analyze gases created by pyrolysis of samples. During AMASE, a Hiden Evolved Gas Analysis-Mass Spectrometer (EGA-MS) system represented the EGA-MS capability of SAM. Another MSL instrument, CheMin, will use x-ray diffraction (XRD) and x-ray fluorescence (XRF) to perform quantitative mineralogical characterization of samples [e.g., 2]. Field-portable versions of CheMin were used during AMASE. AMASE 2010 focused on two sites that represented biotic and abiotic analogs. The abiotic site was the basaltic Sigurdfjell vent complex, which contains Mars-analog carbonate cements including carbonate globules which are excellent analogs for the globules in the ALH84001 martian meteorite [e.g., 3, 4]. The biotic site was the Knorringfjell fossil methane seep, which featured carbonates precipitated in a methane-supported chemosynthetic community [5]. This contribution focuses on EGA-MS analyses of samples from each site, with mineralogy comparisons to CheMin team results. The results give insight into organic content and organic-mineral associations, as well as some constraints on the minerals present.

  1. Field Efficacy of New Larvicide Products for Control of Multi-Resistant Aedes aegypti Populations in Martinique (French West Indies)

    PubMed Central

    Marcombe, Sébastien; Darriet, Frédéric; Agnew, Philip; Etienne, Manuel; Yp-Tcha, Marie-Michelle; Yébakima, André; Corbel, Vincent

    2011-01-01

    World-wide dengue vector control is hampered by the spread of insecticide resistance in Aedes aegypti. We report the resistance status of a wild Ae. aegypti population from Martinique (Vauclin) to conventional larvicides (Bacillus thuringiensis var israeliensis [Bti] and temephos) and potential alternatives (spinosad, diflubenzuron, and pyriproxyfen). The efficacy and residual activity of these insecticides were evaluated under simulated and field conditions. The Vauclin strain exhibited a high level of resistance to temephos, a tolerance to insect growth regulators, and full susceptibility to spinosad and Bti. In simulated trials, pyriproxyfen and Bti showed long residual activities in permanent breeding containers (28 and 37 weeks), whereas under field conditions they failed to curtail Ae. aegypti populations after four weeks. Conversely, diflubenzuron and spinosad showed a residual efficacy of 16 weeks, suggesting that these chemicals may be promising alternatives to Bti and temephos for controlling insecticide-resistant Ae. aegypti populations. PMID:21212213

  2. Field efficacy of new larvicide products for control of multi-resistant Aedes aegypti populations in Martinique (French West Indies).

    PubMed

    Marcombe, Sébastien; Darriet, Frédéric; Agnew, Philip; Etienne, Manuel; Yp-Tcha, Marie-Michelle; Yébakima, André; Corbel, Vincent

    2011-01-01

    World-wide dengue vector control is hampered by the spread of insecticide resistance in Aedes aegypti. We report the resistance status of a wild Ae. aegypti population from Martinique (Vauclin) to conventional larvicides (Bacillus thuringiensis var israeliensis [Bti] and temephos) and potential alternatives (spinosad, diflubenzuron, and pyriproxyfen). The efficacy and residual activity of these insecticides were evaluated under simulated and field conditions. The Vauclin strain exhibited a high level of resistance to temephos, a tolerance to insect growth regulators, and full susceptibility to spinosad and Bti. In simulated trials, pyriproxyfen and Bti showed long residual activities in permanent breeding containers (28 and 37 weeks), whereas under field conditions they failed to curtail Ae. aegypti populations after four weeks. Conversely, diflubenzuron and spinosad showed a residual efficacy of 16 weeks, suggesting that these chemicals may be promising alternatives to Bti and temephos for controlling insecticide-resistant Ae. aegypti populations.

  3. Effect of temperature and commodity on insecticidal efficacy of spinosad dust against Sitophilus oryzae (Coleoptera: Curculionidae) and Rhyzopertha dominica (Coleoptera: Bostrychidae).

    PubMed

    Athanassiou, Christos G; Kavallieratos, Nickolas G; Chintzoglou, George J; Peteinatos, Gerassimos G; Boukouvala, Maria C; Petrou, Stamatina S; Panoussakis, Emmanouel C

    2008-06-01

    The insecticidal effect of spinosad dust, a formulation that contains 0.125% spinosad, was evaluated against adults of Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) at three temperature levels (20, 25, and 30 degrees C) and four commodities (wheat, Triticum aestivum L.; barley, Hordeum vulgare L.; rice, Oryza sativa L.; and maize, Zea mays L.). For this purpose, quantities of the above-mentioned grains were treated with spinosad at two dose rates (20 and 50 ppm of the formulation, corresponding to 0.025 and 0.06 ppm AI, respectively), and mortality of the exposed adults in the treated grains was measured after 7 and 14 d, whereas progeny production was assessed 65 d later. Generally, for both species, mortality increased with dose, exposure interval, and temperature. For S. oryzae, adult survival and progeny production were lower on wheat than the other grains. After 14 d of exposure, mortality of S. oryzae adults on wheat treated with 50 ppm ranged between 61 and 98%, whereas in the other three commodities it did not exceed 42%. Mortality of R. dominica after 14 d on grains treated 50 ppm ranged between 91 and 100%. For this species, progeny production from exposed parental adults was low in all commodities regardless of temperature. Results indicate that spinosad dust can be used as an alternative to traditional grain protectants, but its effectiveness is highly determined by the target species, commodity, dose, and temperature.

  4. A comparison of bioinsecticide, Spinosad, the semi-synthetic insecticide, Spinetoram and synthetic insecticides as soil drenches for control of Tephritid fruit flies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eight insecticides, including the natural bioinsecticide spinosad and the semi-synthetic insecticide spinetoram, as well as two synthetic pyrethroids, an insect growth regulator, an anthranilic diamide, and an organophosphate were evaluated as soil drench treatments for control of three economically...

  5. Control of Rhagoletis indifferents using Thiamethoxam and Spinosad baits under external fly pressure and its relation to rapidity of kill and residual bait activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Control of western cherry fruit fly (Rhagoletis indifferens Curran) using thiamethoxam in sucrose bait and spinosad bait in cherry orchards under external fly pressure and its relation to rapidity of kill and residual bait activity were studied in Washington and Utah in 2010 and 2011. Thiamethoxam ...

  6. Comparative efficacy on dogs of a single topical treatment with the pioneer fipronil/(S)-methoprene and an oral treatment with spinosad against Ctenocephalides felis

    PubMed Central

    Beugnet, F.; Doyle, V.; Murray, M.; Chalvet-Monfray, K.

    2011-01-01

    In the study reported here, the pioneer fipronil/(S)-methoprene topical product (FRONTLINE® PLUS, Merial Limited, Duluth, GA) was compared to the oral spinosad product (COMFORTIS® Elanco, Greenfield, IN) for efficacy against adult fleas and preventing egg production. The product presentations, doses and labelling were the one applicable in the USA. Using a standard protocol, 200 cat fleas of mixed sex were applied to dogs on Days 1, 7, 14, 21, 28, 35, and 42. Dogs were combed to remove fleas 24 hours post-infestation, the fleas were counted, collected, and then reapplied to each dog following completion of their respective count. At 48 hours post-infestation, comb counts were performed and fleas were removed. No fleas were collected from any dog in the fipronil/(S)-methoprene group at any 24 or 48 hours post-infestation assessment throughout the six weeks study, yielding a preventive efficacy of 100%. For the spinosad treatment, efficacy was 100% at 24 hours and 48 hours through Day 16, and thereafter declined. The results observed in the spinosad-treated dogs were highly variable between animals. At the 24 and 48 hours counts following the Day 21 infestation, only five of eight spinosad-treated dogs (62.5%) were flea-free. Following the Day 28 infestation, spinosad efficacy fell to 85% and 89%, for the 24 hours and 48 hours counts, and only two dogs (25%) were flea free, compared to 100% flea-free dogs in the fipronil/(S)-methoprene group. No fleas were collected from the fipronil/(S)- methoprene treated dogs throughout the entire study, therefore, no eggs were collected at any time from any dog in the group. However, in the spinosad group adult fleas were found on dogs starting on Day 21 and by Day 30, 42 eggs were collected from one dog that had 107 adult fleas counted at 48 hours. At Day 37 and Day 49, more than 100 eggs were collected from each dog in the spinosad-treated and control groups. PMID:22091463

  7. Efficacies of spinosad and a combination of chlorpyrifos-methyl and deltamethrin against phosphine-resistant Rhyzopertha dominica (Coleoptera: Bostrichidae) and Tribolium castaneum (Coleoptera: Tenebrionidae) on wheat.

    PubMed

    Bajracharya, N S; Opit, George P; Talley, J; Jones, C L

    2013-10-01

    Highly phosphine-resistant populations of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) have recently been found in Oklahoma grain storage facilities. These findings necessitate development of a phosphine resistance management strategy to ensure continued effective use of phosphine. Therefore, we investigated the efficacies of two grain insecticides, namely, spinosad applied at label rate of 1 ppm and a mixture of chlorpyrifos-methyl and deltamethrin applied at label rates of 3 and 0.5 ppm, respectively, against highly phosphine-resistant R. dominica and T. castaneum. Adult mortality and progeny production suppression of spinosad- or chlorpyrifos-methyl + deltamethrin mixture-treated wheat that had been stored for 2, 84, 168, 252, and 336 d posttreatment were assessed. We found that both spinosad and chlorpyrifos-methyl + deltamethrin were effective against phosphine-resistant R. dominica and caused 83-100% mortality and also caused total progeny production suppression for all storage periods. Spinosad was not effective against phosphine-resistant T. castaneum; the highest mortality observed was only 3% for all the storage periods. Chlorpyrifos-methyl + deltamethrin was effective against phosphine-resistant T. castaneum only in treated wheat stored for 2 and 84 d, where it caused 93-99% mortality. However, chlorpyrifos-methyl + deltamethrin was effective and achieved total suppression of progeny production in T. castaneum for all the storage periods. Spinosad was not as effective as chlorpyrifos-methyl + deltamethrin mixture at suppressing progeny production of phosphine-resistant T. castaneum. These two insecticides can be used in a phosphine resistance management strategy for R. dominica and T. castaneum in the United States.

  8. Evolving endoscopic surgery.

    PubMed

    Sakai, Paulo; Faintuch, Joel

    2014-06-01

    Since the days of Albukasim in medieval Spain, natural orifices have been regarded not only as a rather repugnant source of bodily odors, fluids and excreta, but also as a convenient invitation to explore and treat the inner passages of the organism. However, surgical ingenuity needed to be matched by appropriate tools and devices. Lack of technologically advanced instrumentation was a strong deterrent during almost a millennium until recent decades when a quantum jump materialized. Endoscopic surgery is currently a vibrant and growing subspecialty, which successfully handles millions of patients every year. Additional opportunities lie ahead which might benefit millions more, however, requiring even more sophisticated apparatuses, particularly in the field of robotics, artificial intelligence, and tissue repair (surgical suturing). This is a particularly exciting and worthwhile challenge, namely of larger and safer endoscopic interventions, followed by seamless and scarless recovery. In synthesis, the future is widely open for those who use together intelligence and creativity to develop new prototypes, new accessories and new techniques. Yet there are many challenges in the path of endoscopic surgery. In this new era of robotic endoscopy, one will likely need a virtual simulator to train and assess the performance of younger doctors. More evidence will be essential in multiple evolving fields, particularly to elucidate whether more ambitious and complex pathways, such as intrathoracic and intraperitoneal surgery via natural orifice transluminal endoscopic surgery (NOTES), are superior or not to conventional techniques.

  9. Evolving endoscopic surgery.

    PubMed

    Sakai, Paulo; Faintuch, Joel

    2014-06-01

    Since the days of Albukasim in medieval Spain, natural orifices have been regarded not only as a rather repugnant source of bodily odors, fluids and excreta, but also as a convenient invitation to explore and treat the inner passages of the organism. However, surgical ingenuity needed to be matched by appropriate tools and devices. Lack of technologically advanced instrumentation was a strong deterrent during almost a millennium until recent decades when a quantum jump materialized. Endoscopic surgery is currently a vibrant and growing subspecialty, which successfully handles millions of patients every year. Additional opportunities lie ahead which might benefit millions more, however, requiring even more sophisticated apparatuses, particularly in the field of robotics, artificial intelligence, and tissue repair (surgical suturing). This is a particularly exciting and worthwhile challenge, namely of larger and safer endoscopic interventions, followed by seamless and scarless recovery. In synthesis, the future is widely open for those who use together intelligence and creativity to develop new prototypes, new accessories and new techniques. Yet there are many challenges in the path of endoscopic surgery. In this new era of robotic endoscopy, one will likely need a virtual simulator to train and assess the performance of younger doctors. More evidence will be essential in multiple evolving fields, particularly to elucidate whether more ambitious and complex pathways, such as intrathoracic and intraperitoneal surgery via natural orifice transluminal endoscopic surgery (NOTES), are superior or not to conventional techniques. PMID:24628672

  10. Emplacement and geochemical evolution of highly evolved syenites investigated by a combined structural and geochemical field study: The lujavrites of the Ilímaussaq complex, SW Greenland

    NASA Astrophysics Data System (ADS)

    Ratschbacher, Barbara C.; Marks, Michael A. W.; Bons, Paul D.; Wenzel, Thomas; Markl, Gregor

    2015-08-01

    Structural mapping and the combined study of magmatic to solid-state deformation textures and mineral compositions in highly evolved nepheline syenites (lujavrites) of the alkaline to peralkaline Ilímaussaq complex (South Greenland) reveal detailed insight into the emplacement and geochemical evolution of the melts they crystallized from. Based on magmatic to solid-state flow textures such as foliations and lineations, we propose that the investigated rock sequence forms a sill-like structure with a steep feeder zone that flattens out over a short distance and intrudes into less evolved overlying units as sub-horizontal sheets by roof uplift. Systematic compositional variation of early-magmatic eudialyte-group minerals (EGM) in the investigated rock sequence monitors the geochemical evolution of the lujavrite-forming melt(s). The chlorine contents of EGM decrease successively upwards within the rock sequence, which probably indicates a successive increase of water activity during differentiation, consistent with a change from sodic pyroxene (aegirine) to sodic amphibole (arfvedsonite) in the mineral assemblage. Both REE contents and Fe/Mn ratios of EGM are promising differentiation indicators, which increase and decrease, respectively, upwards within the sequence due to fractional crystallization. This closed-system evolution is interrupted by a shift towards less evolved melt compositions in one lujavrite unit, for which we assume magma recharge. Our study demonstrates the strength of a combined structural and petrological approach to understand the petrogenesis of an igneous body in more detail and highlights their close connection.

  11. Prokaryote and eukaryote evolvability.

    PubMed

    Poole, Anthony M; Phillips, Matthew J; Penny, David

    2003-05-01

    The concept of evolvability covers a broad spectrum of, often contradictory, ideas. At one end of the spectrum it is equivalent to the statement that evolution is possible, at the other end are untestable post hoc explanations, such as the suggestion that current evolutionary theory cannot explain the evolution of evolvability. We examine similarities and differences in eukaryote and prokaryote evolvability, and look for explanations that are compatible with a wide range of observations. Differences in genome organisation between eukaryotes and prokaryotes meets this criterion. The single origin of replication in prokaryote chromosomes (versus multiple origins in eukaryotes) accounts for many differences because the time to replicate a prokaryote genome limits its size (and the accumulation of junk DNA). Both prokaryotes and eukaryotes appear to switch from genetic stability to genetic change in response to stress. We examine a range of stress responses, and discuss how these impact on evolvability, particularly in unicellular organisms versus complex multicellular ones. Evolvability is also limited by environmental interactions (including competition) and we describe a model that places limits on potential evolvability. Examples are given of its application to predator competition and limits to lateral gene transfer. We suggest that unicellular organisms evolve largely through a process of metabolic change, resulting in biochemical diversity. Multicellular organisms evolve largely through morphological changes, not through extensive changes to cellular biochemistry. PMID:12689728

  12. Stochastically evolving networks

    NASA Astrophysics Data System (ADS)

    Chan, Derek Y.; Hughes, Barry D.; Leong, Alex S.; Reed, William J.

    2003-12-01

    We discuss a class of models for the evolution of networks in which new nodes are recruited into the network at random times, and links between existing nodes that are not yet directly connected may also form at random times. The class contains both models that produce “small-world” networks and less tightly linked models. We produce both trees, appropriate in certain biological applications, and networks in which closed loops can appear, which model communication networks and networks of human sexual interactions. One of our models is closely related to random recursive trees, and some exact results known in that context can be exploited. The other models are more subtle and difficult to analyze. Our analysis includes a number of exact results for moments, correlations, and distributions of coordination number and network size. We report simulations and also discuss some mean-field approximations. If the system has evolved for a long time and the state of a random node (which thus has a random age) is observed, power-law distributions for properties of the system arise in some of these models.

  13. Evolvable Systems for Space Applications

    NASA Technical Reports Server (NTRS)

    Lohn, Jason; Crawford, James; Globus, Al; Hornby, Gregory; Kraus, William; Larchev, Gregory; Pryor, Anna; Srivastava, Deepak

    2003-01-01

    This article surveys the research of the Evolvable System Group at NASA Ames Research Center. Over the past few years, our group has developed the ability to use evolutionary algorithms in a variety of NASA applications ranging from spacecraft antenna design, fault tolerance for programmable logic chips, atomic force field parameter fitting, analog circuit design, and earth observing satellite scheduling. In some of these applications, evolutionary algorithms match or improve on human performance.

  14. Evolvable Hardware for Space Applications

    NASA Technical Reports Server (NTRS)

    Lohn, Jason; Globus, Al; Hornby, Gregory; Larchev, Gregory; Kraus, William

    2004-01-01

    This article surveys the research of the Evolvable Systems Group at NASA Ames Research Center. Over the past few years, our group has developed the ability to use evolutionary algorithms in a variety of NASA applications ranging from spacecraft antenna design, fault tolerance for programmable logic chips, atomic force field parameter fitting, analog circuit design, and earth observing satellite scheduling. In some of these applications, evolutionary algorithms match or improve on human performance.

  15. REFLECTIONS ON EVOLVING CHANGE.

    PubMed

    Angood, Peter B

    2016-01-01

    Physician leadership is increasingly recognized as pivotal for improved change in health care. Multi-professional care teams, education and leadership are evolving trends that are important for health care's future. PMID:27295737

  16. Performance of Methyl Eugenol + Matrix + Toxicant combinations under field conditions in Hawaii and California for trapping B. dorsalis (Diptera:Tephritidae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New solid formulations containing methyl eugenol and either naled or DDVP toxicants were compared to the standard formulations on cotton wicks in large scale field evaluation in Hawaii. Two “reduced risk” toxicants (spinosad and Rynaxypyr®) were also evaluated. In one test the solid lure-toxicant-ma...

  17. The Evolving Leadership Path of Visual Analytics

    SciTech Connect

    Kluse, Michael; Peurrung, Anthony J.; Gracio, Deborah K.

    2012-01-02

    This is a requested book chapter for an internationally authored book on visual analytics and related fields, coordianted by a UK university and to be published by Springer in 2012. This chapter is an overview of the leadship strategies that PNNL's Jim Thomas and other stakeholders used to establish visual analytics as a field, and how those strategies may evolve in the future.

  18. Field-Evolved Mode 1 Resistance of the Fall Armyworm to Transgenic Cry1Fa-Expressing Corn Associated with Reduced Cry1Fa Toxin Binding and Midgut Alkaline Phosphatase Expression

    PubMed Central

    Jakka, Siva R. K.; Gong, Liang; Hasler, James; Banerjee, Rahul; Sheets, Joel J.; Narva, Kenneth; Blanco, Carlos A.

    2015-01-01

    Insecticidal protein genes from the bacterium Bacillus thuringiensis (Bt) are expressed by transgenic Bt crops (Bt crops) for effective and environmentally safe pest control. The development of resistance to these insecticidal proteins is considered the most serious threat to the sustainability of Bt crops. Resistance in fall armyworm (Spodoptera frugiperda) populations from Puerto Rico to transgenic corn producing the Cry1Fa insecticidal protein resulted, for the first time in the United States, in practical resistance, and Bt corn was withdrawn from the local market. In this study, we used a field-collected Cry1Fa corn-resistant strain (456) of S. frugiperda to identify the mechanism responsible for field-evolved resistance. Binding assays detected reduced Cry1Fa, Cry1Ab, and Cry1Ac but not Cry1Ca toxin binding to midgut brush border membrane vesicles (BBMV) from the larvae of strain 456 compared to that from the larvae of a susceptible (Ben) strain. This binding phenotype is descriptive of the mode 1 type of resistance to Bt toxins. A comparison of the transcript levels for putative Cry1 toxin receptor genes identified a significant downregulation (>90%) of a membrane-bound alkaline phosphatase (ALP), which translated to reduced ALP protein levels and a 75% reduction in ALP activity in BBMV from 456 compared to that of Ben larvae. We cloned and heterologously expressed this ALP from susceptible S. frugiperda larvae and demonstrated that it specifically binds with Cry1Fa toxin. This study provides a thorough mechanistic description of field-evolved resistance to a transgenic Bt crop and supports an association between resistance and reduced Cry1Fa toxin binding and levels of a putative Cry1Fa toxin receptor, ALP, in the midguts of S. frugiperda larvae. PMID:26637593

  19. Field-Evolved Mode 1 Resistance of the Fall Armyworm to Transgenic Cry1Fa-Expressing Corn Associated with Reduced Cry1Fa Toxin Binding and Midgut Alkaline Phosphatase Expression.

    PubMed

    Jakka, Siva R K; Gong, Liang; Hasler, James; Banerjee, Rahul; Sheets, Joel J; Narva, Kenneth; Blanco, Carlos A; Jurat-Fuentes, Juan L

    2015-12-04

    Insecticidal protein genes from the bacterium Bacillus thuringiensis (Bt) are expressed by transgenic Bt crops (Bt crops) for effective and environmentally safe pest control. The development of resistance to these insecticidal proteins is considered the most serious threat to the sustainability of Bt crops. Resistance in fall armyworm (Spodoptera frugiperda) populations from Puerto Rico to transgenic corn producing the Cry1Fa insecticidal protein resulted, for the first time in the United States, in practical resistance, and Bt corn was withdrawn from the local market. In this study, we used a field-collected Cry1Fa corn-resistant strain (456) of S. frugiperda to identify the mechanism responsible for field-evolved resistance. Binding assays detected reduced Cry1Fa, Cry1Ab, and Cry1Ac but not Cry1Ca toxin binding to midgut brush border membrane vesicles (BBMV) from the larvae of strain 456 compared to that from the larvae of a susceptible (Ben) strain. This binding phenotype is descriptive of the mode 1 type of resistance to Bt toxins. A comparison of the transcript levels for putative Cry1 toxin receptor genes identified a significant downregulation (>90%) of a membrane-bound alkaline phosphatase (ALP), which translated to reduced ALP protein levels and a 75% reduction in ALP activity in BBMV from 456 compared to that of Ben larvae. We cloned and heterologously expressed this ALP from susceptible S. frugiperda larvae and demonstrated that it specifically binds with Cry1Fa toxin. This study provides a thorough mechanistic description of field-evolved resistance to a transgenic Bt crop and supports an association between resistance and reduced Cry1Fa toxin binding and levels of a putative Cry1Fa toxin receptor, ALP, in the midguts of S. frugiperda larvae.

  20. Chitobiase activity as an indicator of altered survival, growth and reproduction in Daphnia pulex and Daphnia magna (Crustacea: Cladocera) exposed to spinosad and diflubenzuron.

    PubMed

    Duchet, Claire; Mitie Inafuku, Marília; Caquet, Thierry; Larroque, Michel; Franquet, Evelyne; Lagneau, Christophe; Lagadic, Laurent

    2011-05-01

    Chitobiase is involved in exoskeleton degradation and recycling during the moulting process in arthropods. In aquatic species, the moulting fluid is released into the aqueous environment, and chitobiase activity present therein can be used to follow the dynamics of arthropod populations. Here, chitobiase activity was used for monitoring the impact of mosquito candidate larvicides on Daphnia pulex and Daphnia magna under laboratory conditions. Both species were exposed to spinosad (2, 4, 8 μg L(-1)) and diflubenzuron (0.2, 0.4, 0.8 μg L(-1)) for 14 days. Bacillus thuringiensis var. israelensis (Bti; 0.25, 0.5, 1 μL L(-1)) was used as the reference larvicide. Chitobiase activity, adult survival, individual growth and fecundity, expressed as the number of neonates produced, were measured every 2 days. Average Exposure Concentrations of spinosad were ten-fold lower than the nominal concentrations, whereas only a slight deviation was observed for diflubenzuron. In contrast to Bti, spinosad and diflubenzuron significantly affected both species in terms of adult survival, and production of neonates. As compared to D. pulex, D. magna was more severely affected by diflubenzuron, at low and medium concentrations, with reduced adult growth and much lower chitobiase activity. Chitobiase activity was positively correlated with the individual body length, number of neonates produced between two consecutive observation dates, and number of females and neonates. In addition, the significant positive correlations between chitobiase activity measured on the last sampling date before the first emission of neonates and the cumulative number of neonates produced during the whole observation period strongly support the potential of the activity of this chitinolytic enzyme as a proxy for assessing the dynamics of arthropod populations exposed to larvicides used for mosquito control.

  1. Evolvable Neural Software System

    NASA Technical Reports Server (NTRS)

    Curtis, Steven A.

    2009-01-01

    The Evolvable Neural Software System (ENSS) is composed of sets of Neural Basis Functions (NBFs), which can be totally autonomously created and removed according to the changing needs and requirements of the software system. The resulting structure is both hierarchical and self-similar in that a given set of NBFs may have a ruler NBF, which in turn communicates with other sets of NBFs. These sets of NBFs may function as nodes to a ruler node, which are also NBF constructs. In this manner, the synthetic neural system can exhibit the complexity, three-dimensional connectivity, and adaptability of biological neural systems. An added advantage of ENSS over a natural neural system is its ability to modify its core genetic code in response to environmental changes as reflected in needs and requirements. The neural system is fully adaptive and evolvable and is trainable before release. It continues to rewire itself while on the job. The NBF is a unique, bilevel intelligence neural system composed of a higher-level heuristic neural system (HNS) and a lower-level, autonomic neural system (ANS). Taken together, the HNS and the ANS give each NBF the complete capabilities of a biological neural system to match sensory inputs to actions. Another feature of the NBF is the Evolvable Neural Interface (ENI), which links the HNS and ANS. The ENI solves the interface problem between these two systems by actively adapting and evolving from a primitive initial state (a Neural Thread) to a complicated, operational ENI and successfully adapting to a training sequence of sensory input. This simulates the adaptation of a biological neural system in a developmental phase. Within the greater multi-NBF and multi-node ENSS, self-similar ENI s provide the basis for inter-NBF and inter-node connectivity.

  2. Evidence of field-evolved resistance of Spodoptera frugiperda to Bt corn expressing Cry1F in Brazil that is still sensitive to modified Bt toxins.

    PubMed

    Monnerat, Rose; Martins, Erica; Macedo, Cristina; Queiroz, Paulo; Praça, Lilian; Soares, Carlos Marcelo; Moreira, Helio; Grisi, Isabella; Silva, Joseane; Soberon, Mario; Bravo, Alejandra

    2015-01-01

    Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda.

  3. Evidence of Field-Evolved Resistance of Spodoptera frugiperda to Bt Corn Expressing Cry1F in Brazil That Is Still Sensitive to Modified Bt Toxins

    PubMed Central

    Monnerat, Rose; Martins, Erica; Macedo, Cristina; Queiroz, Paulo; Praça, Lilian; Soares, Carlos Marcelo; Moreira, Helio; Grisi, Isabella; Silva, Joseane; Soberon, Mario; Bravo, Alejandra

    2015-01-01

    Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda. PMID:25830928

  4. Evolvability is inevitable: increasing evolvability without the pressure to adapt.

    PubMed

    Lehman, Joel; Stanley, Kenneth O

    2013-01-01

    Why evolvability appears to have increased over evolutionary time is an important unresolved biological question. Unlike most candidate explanations, this paper proposes that increasing evolvability can result without any pressure to adapt. The insight is that if evolvability is heritable, then an unbiased drifting process across genotypes can still create a distribution of phenotypes biased towards evolvability, because evolvable organisms diffuse more quickly through the space of possible phenotypes. Furthermore, because phenotypic divergence often correlates with founding niches, niche founders may on average be more evolvable, which through population growth provides a genotypic bias towards evolvability. Interestingly, the combination of these two mechanisms can lead to increasing evolvability without any pressure to out-compete other organisms, as demonstrated through experiments with a series of simulated models. Thus rather than from pressure to adapt, evolvability may inevitably result from any drift through genotypic space combined with evolution's passive tendency to accumulate niches.

  5. Regolith Evolved Gas Analyzer

    NASA Technical Reports Server (NTRS)

    Hoffman, John H.; Hedgecock, Jud; Nienaber, Terry; Cooper, Bonnie; Allen, Carlton; Ming, Doug

    2000-01-01

    The Regolith Evolved Gas Analyzer (REGA) is a high-temperature furnace and mass spectrometer instrument for determining the mineralogical composition and reactivity of soil samples. REGA provides key mineralogical and reactivity data that is needed to understand the soil chemistry of an asteroid, which then aids in determining in-situ which materials should be selected for return to earth. REGA is capable of conducting a number of direct soil measurements that are unique to this instrument. These experimental measurements include: (1) Mass spectrum analysis of evolved gases from soil samples as they are heated from ambient temperature to 900 C; and (2) Identification of liberated chemicals, e.g., water, oxygen, sulfur, chlorine, and fluorine. REGA would be placed on the surface of a near earth asteroid. It is an autonomous instrument that is controlled from earth but does the analysis of regolith materials automatically. The REGA instrument consists of four primary components: (1) a flight-proven mass spectrometer, (2) a high-temperature furnace, (3) a soil handling system, and (4) a microcontroller. An external arm containing a scoop or drill gathers regolith samples. A sample is placed in the inlet orifice where the finest-grained particles are sifted into a metering volume and subsequently moved into a crucible. A movable arm then places the crucible in the furnace. The furnace is closed, thereby sealing the inner volume to collect the evolved gases for analysis. Owing to the very low g forces on an asteroid compared to Mars or the moon, the sample must be moved from inlet to crucible by mechanical means rather than by gravity. As the soil sample is heated through a programmed pattern, the gases evolved at each temperature are passed through a transfer tube to the mass spectrometer for analysis and identification. Return data from the instrument will lead to new insights and discoveries including: (1) Identification of the molecular masses of all of the gases

  6. Counseling in Turkey: An Evolving Field

    ERIC Educational Resources Information Center

    Stockton, Rex; Guneri, Oya Yerin

    2011-01-01

    This article provides a brief history of counseling and addresses the current issues and future trends of counseling in Turkey. Special emphasis is placed on the factors that impede the development of school counseling as a discipline.

  7. Palliative care: an evolving field in medicine.

    PubMed

    Eti, Serife

    2011-06-01

    Palliative care is an approach that improves the quality of life of patients and their families facing the problems associated with life-threatening illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems: physical, psychosocial, and spiritual. This article discusses illness trajectories and prognostic estimates, prognostic tools, educating physicians and nurses in palliative care, research in palliative medicine, and palliative care in hospitals and the community. PMID:21628032

  8. Speech processing: An evolving technology

    SciTech Connect

    Crochiere, R.E.; Flanagan, J.L.

    1986-09-01

    As we enter the information age, speech processing is emerging as an important technology for making machines easier and more convenient for humans to use. It is both an old and a new technology - dating back to the invention of the telephone and forward, at least in aspirations, to the capabilities of HAL in 2001. Explosive advances in microelectronics now make it possible to implement economical real-time hardware for sophisticated speech processing - processing that formerly could be demonstrated only in simulations on main-frame computers. As a result, fundamentally new product concepts - as well as new features and functions in existing products - are becoming possible and are being explored in the marketplace. As the introductory piece to this issue, the authors draw a brief perspective on the evolving field of speech processing and assess the technology in the the three constituent sectors: speech coding, synthesis, and recognition.

  9. Our evolving universe

    NASA Astrophysics Data System (ADS)

    Longair, Malcolm S.

    Our Evolving Universe is a lucid, non-technical and infectiously enthusiastic introduction to current astronomy and cosmology. Highly illustrated throughout with the latest colour images from the world's most advanced telescopes, it also provides a colourful view of our Universe. Malcolm Longair takes us on a breathtaking tour of the most dramatic recent results astronomers have on the birth of stars, the hunt for black holes and dark matter, on gravitational lensing and the latest tests of the Big Bang. He leads the reader right up to understand the key questions that future research in astronomy and cosmology must answer. A clear and comprehensive glossary of technical terms is also provided. For the general reader, student or professional wishing to understand the key questions today's astronomers and cosmologists are trying to answer, this is an invaluable and inspiring read.

  10. Evolving synergetic interactions.

    PubMed

    Wu, Bin; Arranz, Jordi; Du, Jinming; Zhou, Da; Traulsen, Arne

    2016-07-01

    Cooperators forgo their own interests to benefit others. This reduces their fitness and thus cooperators are not likely to spread based on natural selection. Nonetheless, cooperation is widespread on every level of biological organization ranging from bacterial communities to human society. Mathematical models can help to explain under which circumstances cooperation evolves. Evolutionary game theory is a powerful mathematical tool to depict the interactions between cooperators and defectors. Classical models typically involve either pairwise interactions between individuals or a linear superposition of these interactions. For interactions within groups, however, synergetic effects may arise: their outcome is not just the sum of its parts. This is because the payoffs via a single group interaction can be different from the sum of any collection of two-player interactions. Assuming that all interactions start from pairs, how can such synergetic multiplayer games emerge from simpler pairwise interactions? Here, we present a mathematical model that captures the transition from pairwise interactions to synergetic multiplayer ones. We assume that different social groups have different breaking rates. We show that non-uniform breaking rates do foster the emergence of synergy, even though individuals always interact in pairs. Our work sheds new light on the mechanisms underlying such synergetic interactions. PMID:27466437

  11. Communicability across evolving networks

    NASA Astrophysics Data System (ADS)

    Grindrod, Peter; Parsons, Mark C.; Higham, Desmond J.; Estrada, Ernesto

    2011-04-01

    Many natural and technological applications generate time-ordered sequences of networks, defined over a fixed set of nodes; for example, time-stamped information about “who phoned who” or “who came into contact with who” arise naturally in studies of communication and the spread of disease. Concepts and algorithms for static networks do not immediately carry through to this dynamic setting. For example, suppose A and B interact in the morning, and then B and C interact in the afternoon. Information, or disease, may then pass from A to C, but not vice versa. This subtlety is lost if we simply summarize using the daily aggregate network given by the chain A-B-C. However, using a natural definition of a walk on an evolving network, we show that classic centrality measures from the static setting can be extended in a computationally convenient manner. In particular, communicability indices can be computed to summarize the ability of each node to broadcast and receive information. The computations involve basic operations in linear algebra, and the asymmetry caused by time’s arrow is captured naturally through the noncommutativity of matrix-matrix multiplication. Illustrative examples are given for both synthetic and real-world communication data sets. We also discuss the use of the new centrality measures for real-time monitoring and prediction.

  12. Evolving Concepts of Asthma.

    PubMed

    Gauthier, Marc; Ray, Anuradha; Wenzel, Sally E

    2015-09-15

    Our understanding of asthma has evolved over time from a singular disease to a complex of various phenotypes, with varied natural histories, physiologies, and responses to treatment. Early therapies treated most patients with asthma similarly, with bronchodilators and corticosteroids, but these therapies had varying degrees of success. Similarly, despite initial studies that identified an underlying type 2 inflammation in the airways of patients with asthma, biologic therapies targeted toward these type 2 pathways were unsuccessful in all patients. These observations led to increased interest in phenotyping asthma. Clinical approaches, both biased and later unbiased/statistical approaches to large asthma patient cohorts, identified a variety of patient characteristics, but they also consistently identified the importance of age of onset of disease and the presence of eosinophils in determining clinically relevant phenotypes. These paralleled molecular approaches to phenotyping that developed an understanding that not all patients share a type 2 inflammatory pattern. Using biomarkers to select patients with type 2 inflammation, repeated trials of biologics directed toward type 2 cytokine pathways saw newfound success, confirming the importance of phenotyping in asthma. Further research is needed to clarify additional clinical and molecular phenotypes, validate predictive biomarkers, and identify new areas for possible interventions.

  13. Evolving paradigms in pharmacovigilance.

    PubMed

    Brewster, Wendy; Gibbs, Trevor; Lacroix, Karol; Murray, Alison; Tydeman, Michael; Almenoff, June

    2006-05-01

    All medicines have adverse effects as well as benefits. The aim of pharmacovigilance is to protect public health by monitoring medicines to identify and evaluate issues and ensure that the overall benefits outweigh the potential risks. The tools and processes used in pharmacovigilance are continually evolving. Increasingly sophisticated tools are being designed to evaluate safety data from clinical trials to enhance the likelihood of detecting safety signals ahead of product registration. Methods include integration of safety data throughout development, meta-analytical techniques, quantitative and qualitative methods for evaluation of adverse event data and graphical tools to explore laboratory and biometric data. Electronic data capture facilitates monitoring of ongoing studies so that it is possible to promptly identify potential issues and manage patient safety. In addition, GSK employs a number of proactive methods for post-marketing signal detection and knowledge management using state-of-the-art statistical and analytical tools. Using these tools, together with safety data collected through pharmacoepidemiologic studies, literature and spontaneous reporting, potential adverse drug reactions can be better identified in marketed products. In summary, the information outlined in this paper provides a valuable benchmark for risk management and pharmacovigilance in pharmaceutical development.

  14. Evolving synergetic interactions

    PubMed Central

    Wu, Bin; Arranz, Jordi; Du, Jinming; Zhou, Da; Traulsen, Arne

    2016-01-01

    Cooperators forgo their own interests to benefit others. This reduces their fitness and thus cooperators are not likely to spread based on natural selection. Nonetheless, cooperation is widespread on every level of biological organization ranging from bacterial communities to human society. Mathematical models can help to explain under which circumstances cooperation evolves. Evolutionary game theory is a powerful mathematical tool to depict the interactions between cooperators and defectors. Classical models typically involve either pairwise interactions between individuals or a linear superposition of these interactions. For interactions within groups, however, synergetic effects may arise: their outcome is not just the sum of its parts. This is because the payoffs via a single group interaction can be different from the sum of any collection of two-player interactions. Assuming that all interactions start from pairs, how can such synergetic multiplayer games emerge from simpler pairwise interactions? Here, we present a mathematical model that captures the transition from pairwise interactions to synergetic multiplayer ones. We assume that different social groups have different breaking rates. We show that non-uniform breaking rates do foster the emergence of synergy, even though individuals always interact in pairs. Our work sheds new light on the mechanisms underlying such synergetic interactions. PMID:27466437

  15. Bioefficacy of larvicdial and pupicidal properties of Carica papaya (Caricaceae) leaf extract and bacterial insecticide, spinosad, against chikungunya vector, Aedes aegypti (Diptera: Culicidae).

    PubMed

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Naresh Kumar, Arjunan; Vincent, Savariar; Hwang, Jiang-Shiou

    2012-02-01

    The present study was carried out to establish the properties of Carica papaya leaf extract and bacterial insecticide, spinosad on larvicidal and pupicidal activity against the chikungunya vector, Aedes aegypti. The medicinal plants were collected from the area around Bharathiar University, Coimbatore, India. C. papaya leaf was washed with tap water and shade-dried at room temperature. An electrical blender powdered the dried plant materials (leaves). The powder (500 g) of the leaf was extracted with 1.5 l of organic solvents of methanol for 8 h using a Soxhlet apparatus and then filtered. The crude leaf extracts were evaporated to dryness in a rotary vacuum evaporator. The plant extract showed larvicidal and pupicidal effects after 24 h of exposure; however, the highest larval and pupal mortality was found in the leaf extract of methanol C. papaya against the first- to fourth-instar larvae and pupae of values LC(50) = I instar was 51.76 ppm, II instar was 61.87 ppm, III instar was 74.07 ppm, and IV instar was 82.18 ppm, and pupae was 440.65 ppm, respectively, and bacterial insecticide, spinosad against the first to fourth instar larvae and pupae of values LC(50) = I instar was 51.76 ppm, II instar was 61.87 ppm, III instar was 74.07 ppm, and IV instar was 82.18 ppm, and pupae was 93.44 ppm, respectively. Moreover, combined treatment of values of LC(50) = I instar was 55.77 ppm, II instar was 65.77 ppm, III instar was 76.36 ppm, and IV instar was 92.78 ppm, and pupae was 107.62 ppm, respectively. No mortality was observed in the control. The results that the leaves extract of C. papaya and bacterial insecticide, Spinosad is promising as good larvicidal and pupicidal properties of against chikungunya vector, A. aegypti. This is an ideal eco-friendly approach for the control of chikungunya vector, A. aegypti as target species of vector control programs.

  16. How do drumlin patterns evolve?

    NASA Astrophysics Data System (ADS)

    Ely, Jeremy; Clark, Chris; Spagnolo, Matteo; Hughes, Anna

    2016-04-01

    The flow of a geomorphic agent over a sediment bed creates patterns in the substrate composed of bedforms. Ice is no exception to this, organising soft sedimentary substrates into subglacial bedforms. As we are yet to fully observe their initiation and evolution beneath a contemporary ice mass, little is known about how patterns in subglacial bedforms develop. Here we study 36,222 drumlins, divided into 72 flowsets, left behind by the former British-Irish Ice sheet. These flowsets provide us with 'snapshots' of drumlin pattern development. The probability distribution functions of the size and shape metrics of drumlins within these flowsets were analysed to determine whether behaviour that is common of other patterned phenomena has occurred. Specifically, we ask whether drumlins i) are printed at a specific scale; ii) grow or shrink after they initiate; iii) stabilise at a specific size and shape; and iv) migrate. Our results indicate that drumlins initiate at a minimum size and spacing. After initiation, the log-normal distribution of drumlin size and shape metrics suggests that drumlins grow, or possibly shrink, as they develop. We find no evidence for stabilisation in drumlin length, supporting the idea of a subglacial bedform continuum. Drumlin migration is difficult to determine from the palaeo-record. However, there are some indications that a mixture of static and mobile drumlins occurs, which could potentially lead to collisions, cannibalisation and coarsening. Further images of modern drumlin fields evolving beneath ice are required to capture stages of drumlin pattern evolution.

  17. Evolving virtual creatures and catapults.

    PubMed

    Chaumont, Nicolas; Egli, Richard; Adami, Christoph

    2007-01-01

    We present a system that can evolve the morphology and the controller of virtual walking and block-throwing creatures (catapults) using a genetic algorithm. The system is based on Sims' work, implemented as a flexible platform with an off-the-shelf dynamics engine. Experiments aimed at evolving Sims-type walkers resulted in the emergence of various realistic gaits while using fairly simple objective functions. Due to the flexibility of the system, drastically different morphologies and functions evolved with only minor modifications to the system and objective function. For example, various throwing techniques evolved when selecting for catapults that propel a block as far as possible. Among the strategies and morphologies evolved, we find the drop-kick strategy, as well as the systematic invention of the principle behind the wheel, when allowing mutations to the projectile. PMID:17355189

  18. Evolving virtual creatures and catapults.

    PubMed

    Chaumont, Nicolas; Egli, Richard; Adami, Christoph

    2007-01-01

    We present a system that can evolve the morphology and the controller of virtual walking and block-throwing creatures (catapults) using a genetic algorithm. The system is based on Sims' work, implemented as a flexible platform with an off-the-shelf dynamics engine. Experiments aimed at evolving Sims-type walkers resulted in the emergence of various realistic gaits while using fairly simple objective functions. Due to the flexibility of the system, drastically different morphologies and functions evolved with only minor modifications to the system and objective function. For example, various throwing techniques evolved when selecting for catapults that propel a block as far as possible. Among the strategies and morphologies evolved, we find the drop-kick strategy, as well as the systematic invention of the principle behind the wheel, when allowing mutations to the projectile.

  19. Spacetimes containing slowly evolving horizons

    SciTech Connect

    Kavanagh, William; Booth, Ivan

    2006-08-15

    Slowly evolving horizons are trapping horizons that are ''almost'' isolated horizons. This paper reviews their definition and discusses several spacetimes containing such structures. These include certain Vaidya and Tolman-Bondi solutions as well as (perturbatively) tidally distorted black holes. Taking into account the mass scales and orders of magnitude that arise in these calculations, we conjecture that slowly evolving horizons are the norm rather than the exception in astrophysical processes that involve stellar-scale black holes.

  20. Natural selection promotes antigenic evolvability.

    PubMed

    Graves, Christopher J; Ros, Vera I D; Stevenson, Brian; Sniegowski, Paul D; Brisson, Dustin

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide an experimentally tractable system to test whether natural selection has favored mechanisms that increase evolvability. Many antigenic variation systems consist of paralogous unexpressed 'cassettes' that recombine into an expression site to rapidly alter the expressed protein. Importantly, the magnitude of antigenic change is a function of the genetic diversity among the unexpressed cassettes. Thus, evidence that selection favors among-cassette diversity is direct evidence that natural selection promotes antigenic evolvability. We used the Lyme disease bacterium, Borrelia burgdorferi, as a model to test the prediction that natural selection favors amino acid diversity among unexpressed vls cassettes and thereby promotes evolvability in a primary surface antigen, VlsE. The hypothesis that diversity among vls cassettes is favored by natural selection was supported in each B. burgdorferi strain analyzed using both classical (dN/dS ratios) and Bayesian population genetic analyses of genetic sequence data. This hypothesis was also supported by the conservation of highly mutable tandem-repeat structures across B. burgdorferi strains despite a near complete absence of sequence conservation. Diversification among vls cassettes due to natural selection and mutable repeat structures promotes long-term antigenic evolvability of VlsE. These findings provide a direct demonstration that molecular mechanisms that enhance evolvability of surface antigens are an evolutionary adaptation. The molecular evolutionary processes identified here can serve as a model for the evolution of antigenic evolvability in many pathogens which utilize similar strategies to establish chronic infections.

  1. Robustness to Faults Promotes Evolvability: Insights from Evolving Digital Circuits

    PubMed Central

    Nolfi, Stefano

    2016-01-01

    We demonstrate how the need to cope with operational faults enables evolving circuits to find more fit solutions. The analysis of the results obtained in different experimental conditions indicates that, in absence of faults, evolution tends to select circuits that are small and have low phenotypic variability and evolvability. The need to face operation faults, instead, drives evolution toward the selection of larger circuits that are truly robust with respect to genetic variations and that have a greater level of phenotypic variability and evolvability. Overall our results indicate that the need to cope with operation faults leads to the selection of circuits that have a greater probability to generate better circuits as a result of genetic variation with respect to a control condition in which circuits are not subjected to faults. PMID:27409589

  2. Signing Apes and Evolving Linguistics.

    ERIC Educational Resources Information Center

    Stokoe, William C.

    Linguistics retains from its antecedents, philology and the study of sacred writings, some of their apologetic and theological bias. Thus it has not been able to face squarely the question how linguistic function may have evolved from animal communication. Chimpanzees' use of signs from American Sign Language forces re-examination of language…

  3. Evolving Sensitivity Balances Boolean Networks

    PubMed Central

    Luo, Jamie X.; Turner, Matthew S.

    2012-01-01

    We investigate the sensitivity of Boolean Networks (BNs) to mutations. We are interested in Boolean Networks as a model of Gene Regulatory Networks (GRNs). We adopt Ribeiro and Kauffman’s Ergodic Set and use it to study the long term dynamics of a BN. We define the sensitivity of a BN to be the mean change in its Ergodic Set structure under all possible loss of interaction mutations. Insilico experiments were used to selectively evolve BNs for sensitivity to losing interactions. We find that maximum sensitivity was often achievable and resulted in the BNs becoming topologically balanced, i.e. they evolve towards network structures in which they have a similar number of inhibitory and excitatory interactions. In terms of the dynamics, the dominant sensitivity strategy that evolved was to build BNs with Ergodic Sets dominated by a single long limit cycle which is easily destabilised by mutations. We discuss the relevance of our findings in the context of Stem Cell Differentiation and propose a relationship between pluripotent stem cells and our evolved sensitive networks. PMID:22586459

  4. Thermal and evolved gas analyzer

    NASA Technical Reports Server (NTRS)

    Williams, M. S.; Boynton, W. V.; James, R. L.; Verts, W. T.; Bailey, S. H.; Hamara, D. K.

    1998-01-01

    The Thermal and Evolved Gas Analyzer (TEGA) instrument will perform calorimetry and evolved gas analysis on soil samples collected from the Martian surface. TEGA is one of three instruments, along with a robotic arm, that form the Mars Volatile and Climate Survey (MVACS) payload. The other instruments are a stereo surface imager, built by Peter Smith of the University of Arizona and a meteorological station, built by JPL. The MVACS lander will investigate a Martian landing site at approximately 70 deg south latitude. Launch will take place from Kennedy Space Center in January, 1999. The TEGA project started in February, 1996. In the intervening 24 months, a flight instrument concept has been designed, prototyped, built as an engineering model and flight model, and tested. The instrument performs laboratory-quality differential-scanning calorimetry (DSC) over the temperature range of Mars ambient to 1400K. Low-temperature volatiles (water and carbon dioxide ices) and the carbonates will be analyzed in this temperature range. Carbonates melt and evolve carbon dioxide at temperatures above 600 C. Evolved oxygen (down to a concentration of 1 ppm) is detected, and C02 and water vapor and the isotopic variations of C02 and water vapor are detected and their concentrations measured. The isotopic composition provides important tests of the theory of solar system formation.

  5. Slippery Texts and Evolving Literacies

    ERIC Educational Resources Information Center

    Mackey, Margaret

    2007-01-01

    The idea of "slippery texts" provides a useful descriptor for materials that mutate and evolve across different media. Eight adult gamers, encountering the slippery text "American McGee's Alice," demonstrate a variety of ways in which players attempt to manage their attention as they encounter a new text with many resonances. The range of their…

  6. The Evolving Status of Photojournalism Education. ERIC Digest.

    ERIC Educational Resources Information Center

    Cookman, Claude

    Noting that new technologies are resulting in extensive changes in the field of photojournalism, both as it is practiced and taught, this Digest reviews this rapidly evolving field of education and professional practice. It discusses what digital photography is; the history of digital photography; how digital photography has changed…

  7. When did oxygenic photosynthesis evolve?

    PubMed

    Buick, Roger

    2008-08-27

    The atmosphere has apparently been oxygenated since the 'Great Oxidation Event' ca 2.4 Ga ago, but when the photosynthetic oxygen production began is debatable. However, geological and geochemical evidence from older sedimentary rocks indicates that oxygenic photosynthesis evolved well before this oxygenation event. Fluid-inclusion oils in ca 2.45 Ga sandstones contain hydrocarbon biomarkers evidently sourced from similarly ancient kerogen, preserved without subsequent contamination, and derived from organisms producing and requiring molecular oxygen. Mo and Re abundances and sulphur isotope systematics of slightly older (2.5 Ga) kerogenous shales record a transient pulse of atmospheric oxygen. As early as ca 2.7 Ga, stromatolites and biomarkers from evaporative lake sediments deficient in exogenous reducing power strongly imply that oxygen-producing cyanobacteria had already evolved. Even at ca 3.2 Ga, thick and widespread kerogenous shales are consistent with aerobic photoautrophic marine plankton, and U-Pb data from ca 3.8 Ga metasediments suggest that this metabolism could have arisen by the start of the geological record. Hence, the hypothesis that oxygenic photosynthesis evolved well before the atmosphere became permanently oxygenated seems well supported. PMID:18468984

  8. When did oxygenic photosynthesis evolve?

    PubMed

    Buick, Roger

    2008-08-27

    The atmosphere has apparently been oxygenated since the 'Great Oxidation Event' ca 2.4 Ga ago, but when the photosynthetic oxygen production began is debatable. However, geological and geochemical evidence from older sedimentary rocks indicates that oxygenic photosynthesis evolved well before this oxygenation event. Fluid-inclusion oils in ca 2.45 Ga sandstones contain hydrocarbon biomarkers evidently sourced from similarly ancient kerogen, preserved without subsequent contamination, and derived from organisms producing and requiring molecular oxygen. Mo and Re abundances and sulphur isotope systematics of slightly older (2.5 Ga) kerogenous shales record a transient pulse of atmospheric oxygen. As early as ca 2.7 Ga, stromatolites and biomarkers from evaporative lake sediments deficient in exogenous reducing power strongly imply that oxygen-producing cyanobacteria had already evolved. Even at ca 3.2 Ga, thick and widespread kerogenous shales are consistent with aerobic photoautrophic marine plankton, and U-Pb data from ca 3.8 Ga metasediments suggest that this metabolism could have arisen by the start of the geological record. Hence, the hypothesis that oxygenic photosynthesis evolved well before the atmosphere became permanently oxygenated seems well supported.

  9. Evolving Systems and Adaptive Key Component Control

    NASA Technical Reports Server (NTRS)

    Frost, Susan A.; Balas, Mark J.

    2009-01-01

    We propose a new framework called Evolving Systems to describe the self-assembly, or autonomous assembly, of actively controlled dynamical subsystems into an Evolved System with a higher purpose. An introduction to Evolving Systems and exploration of the essential topics of the control and stability properties of Evolving Systems is provided. This chapter defines a framework for Evolving Systems, develops theory and control solutions for fundamental characteristics of Evolving Systems, and provides illustrative examples of Evolving Systems and their control with adaptive key component controllers.

  10. Life cycle planning: An evolving concept

    SciTech Connect

    Moore, P.J.R.; Gorman, I.G.

    1994-12-31

    Life-cycle planning is an evolving concept in the management of oil and gas projects. BHP Petroleum now interprets this idea to include all development planning from discovery and field appraisal to final abandonment and includes safety, environmental, technical, plant, regulatory, and staffing issues. This article describes in the context of the Timor Sea, how despite initial successes and continuing facilities upgrades, BHPP came to perceive that current operations could be the victim of early development successes, particularly in the areas of corrosion and maintenance. The search for analogies elsewhere lead to the UK North Sea, including the experiences of Britoil and BP, both of which performed detailed Life of Field studies in the later eighties. These materials have been used to construct a format and content for total Life-cycle plans in general and the social changes required to ensure their successful application in Timor Sea operations and deployment throughout Australia.

  11. Foraging Allocation in the Honey Bee, Apis mellifera L. (Hymenoptera, Apidae), Tuned by the Presence of the Spinosad-Based Pesticide GF-120.

    PubMed

    Cabrera-Marín, N V; Liedo, P; Vandame, R; Sánchez, D

    2015-04-01

    Agroecosystem management commonly involves the use of pesticides. As a result, a heterogeneous landscape is created, in which suitable and unsuitable spaces are defined by the absence/presence of pesticides. In this study, we explored how foragers of the honey bee, Apis mellifera L., adapt to such context. We specifically evaluated the effect of GF-120, a spinosad-based fruit fly toxic bait, on the allocation of foragers between food sources under the hypothesis that foragers will move from food sources with GF-120 to food sources without it. We thus carried out three experiments: in experiment 1, a group of foragers was trained to collect honey solution from a feeder; next, this feeder offered a GF-120/honey solution. A minority of foragers continued collecting the GF-120/honey solution. In experiment 2, we trained two groups of foragers from a colony to two food sources equally rewarding. Next, GF-120 was added to one of the food sources. We found that the majority of foragers moved from the GF-120-treated feeder to the feeder without GF-120 and that the minority that continued visiting the GF-120-treated feeder did not collect the GF-120/honey solution. In a third experiment, we wanted to know if foragers in an experimental setup as in experiment 1 would perform waggle dances: none of the foragers that collected GF-120/honey were observed dancing. Our results emphasize the importance of "food refuges" for non-target species, since they minimize the impact of agrochemicals upon them. PMID:26013135

  12. Evolving Robust Gene Regulatory Networks

    PubMed Central

    Noman, Nasimul; Monjo, Taku; Moscato, Pablo; Iba, Hitoshi

    2015-01-01

    Design and implementation of robust network modules is essential for construction of complex biological systems through hierarchical assembly of ‘parts’ and ‘devices’. The robustness of gene regulatory networks (GRNs) is ascribed chiefly to the underlying topology. The automatic designing capability of GRN topology that can exhibit robust behavior can dramatically change the current practice in synthetic biology. A recent study shows that Darwinian evolution can gradually develop higher topological robustness. Subsequently, this work presents an evolutionary algorithm that simulates natural evolution in silico, for identifying network topologies that are robust to perturbations. We present a Monte Carlo based method for quantifying topological robustness and designed a fitness approximation approach for efficient calculation of topological robustness which is computationally very intensive. The proposed framework was verified using two classic GRN behaviors: oscillation and bistability, although the framework is generalized for evolving other types of responses. The algorithm identified robust GRN architectures which were verified using different analysis and comparison. Analysis of the results also shed light on the relationship among robustness, cooperativity and complexity. This study also shows that nature has already evolved very robust architectures for its crucial systems; hence simulation of this natural process can be very valuable for designing robust biological systems. PMID:25616055

  13. Netgram: Visualizing Communities in Evolving Networks.

    PubMed

    Mall, Raghvendra; Langone, Rocco; Suykens, Johan A K

    2015-01-01

    Real-world complex networks are dynamic in nature and change over time. The change is usually observed in the interactions within the network over time. Complex networks exhibit community like structures. A key feature of the dynamics of complex networks is the evolution of communities over time. Several methods have been proposed to detect and track the evolution of these groups over time. However, there is no generic tool which visualizes all the aspects of group evolution in dynamic networks including birth, death, splitting, merging, expansion, shrinkage and continuation of groups. In this paper, we propose Netgram: a tool for visualizing evolution of communities in time-evolving graphs. Netgram maintains evolution of communities over 2 consecutive time-stamps in tables which are used to create a query database using the sql outer-join operation. It uses a line-based visualization technique which adheres to certain design principles and aesthetic guidelines. Netgram uses a greedy solution to order the initial community information provided by the evolutionary clustering technique such that we have fewer line cross-overs in the visualization. This makes it easier to track the progress of individual communities in time evolving graphs. Netgram is a generic toolkit which can be used with any evolutionary community detection algorithm as illustrated in our experiments. We use Netgram for visualization of topic evolution in the NIPS conference over a period of 11 years and observe the emergence and merging of several disciplines in the field of information processing systems. PMID:26356538

  14. Data-driven Simulations of Evolving Active Regions

    NASA Astrophysics Data System (ADS)

    Cheung, M.; DeRosa, M. L.

    2011-12-01

    We present results from numerical simulations of coronal field evolution in response to photospheric driving. In the simulations, the coronal field evolves according to magnetofriction, which ensures that the model field evolves toward a non-linear force-free state. Unlike static field extrapolation methods, this approach takes into account the history of the photospheric field evolution. This allows for the formation of flux ropes as well as current sheets between magnetic domains of connectivity. Using time sequences of HMI magnetograms as the bottom boundary condition, we apply this method to model the emergence and evolution of various active regions. Comparisons of the models with AIA observations and with HMI vector magnetogram inversions will be discussed.

  15. Primordial evolvability: Impasses and challenges.

    PubMed

    Vasas, Vera; Fernando, Chrisantha; Szilágyi, András; Zachár, István; Santos, Mauro; Szathmáry, Eörs

    2015-09-21

    While it is generally agreed that some kind of replicating non-living compounds were the precursors of life, there is much debate over their possible chemical nature. Metabolism-first approaches propose that mutually catalytic sets of simple organic molecules could be capable of self-replication and rudimentary chemical evolution. In particular, the graded autocatalysis replication domain (GARD) model, depicting assemblies of amphiphilic molecules, has received considerable interest. The system propagates compositional information across generations and is suggested to be a target of natural selection. However, evolutionary simulations indicate that the system lacks selectability (i.e. selection has negligible effect on the equilibrium concentrations). We elaborate on the lessons learnt from the example of the GARD model and, more widely, on the issue of evolvability, and discuss the implications for similar metabolism-first scenarios. We found that simple incorporation-type chemistry based on non-covalent bonds, as assumed in GARD, is unlikely to result in alternative autocatalytic cycles when catalytic interactions are randomly distributed. An even more serious problem stems from the lognormal distribution of catalytic factors, causing inherent kinetic instability of such loops, due to the dominance of efficiently catalyzed components that fail to return catalytic aid. Accordingly, the dynamics of the GARD model is dominated by strongly catalytic, but not auto-catalytic, molecules. Without effective autocatalysis, stable hereditary propagation is not possible. Many repetitions and different scaling of the model come to no rescue. Despite all attempts to show the contrary, the GARD model is not evolvable, in contrast to reflexively autocatalytic networks, complemented by rare uncatalyzed reactions and compartmentation. The latter networks, resting on the creation and breakage of chemical bonds, can generate novel ('mutant') autocatalytic loops from a given set of

  16. Isotopic Analysis and Evolved Gases

    NASA Technical Reports Server (NTRS)

    Swindle, Timothy D.; Boynton, William V.; Chutjian, Ara; Hoffman, John H.; Jordan, Jim L.; Kargel, Jeffrey S.; McEntire, Richard W.; Nyquist, Larry

    1996-01-01

    Precise measurements of the chemical, elemental, and isotopic composition of planetary surface material and gases, and observed variations in these compositions, can contribute significantly to our knowledge of the source(s), ages, and evolution of solar system materials. The analyses discussed in this paper are mostly made by mass spectrometers or some other type of mass analyzer, and address three broad areas of interest: (1) atmospheric composition - isotopic, elemental, and molecular, (2) gases evolved from solids, and (3) solids. Current isotopic data on nine elements, mostly from in situ analysis, but also from meteorites and telescopic observations are summarized. Potential instruments for isotopic analysis of lunar, Martian, Venusian, Mercury, and Pluto surfaces, along with asteroid, cometary and icy satellites, surfaces are discussed.

  17. Managing Oriental Fruit Fly, Bactrocera dorsalis (Diptera: Tephritidae), Using Spinosad-Based Protein Bait Sprays in Papaya Orchards in Hawaii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficacy of GF-120 Fruit Fly Bait was evaluated as a control of female oriental fruit fly, Bactrocera dorsalis (Hendel) in papaya orchards in Hawaii. Two important components of this study were field sanitation and mass trapping using the male-specific lure methyl eugenol. Three different spray ...

  18. Planets in Evolved Binary Systems

    NASA Astrophysics Data System (ADS)

    Perets, Hagai B.

    2011-03-01

    Exo-planets are typically thought to form in protoplanetary disks left over from protostellar disk of their newly formed host star. However, additional planetary formation and evolution routes may exist in old evolved binary systems. Here we discuss the implications of binary stellar evolution on planetary systems in such environments. In these binary systems stellar evolution could lead to the formation of symbiotic stars, where mass is lost from one star and could be transferred to its binary companion, and may form an accretion disk around it. This raises the possibility that such a disk could provide the necessary environment for the formation of a new, second generation of planets in both circumstellar or circumbinary configurations. Pre-existing first generation planets surviving the post-MS evolution of such systems would be dynamically effected by the mass loss in the systems and may also interact with the newly formed disk. Such planets and/or planetesimals may also serve as seeds for the formation of the second generation planets, and/or interact with them, possibly forming atypical planetary systems. Second generation planetary systems should be typically found in white dwarf binary systems, and may show various observational signatures. Most notably, second generation planets could form in environment which are inaccessible, or less favorable, for first generation planets. The orbital phase space available for the second generation planets could be forbidden (in terms of the system stability) to first generation planets in the pre-evolved progenitor binaries. In addition planets could form in metal poor environments such as globular clusters and/or in double compact object binaries. Observations of exo-planets in such forbidden or unfavorable regions could possibly serve to uniquely identify their second generation character. Finally, we point out a few observed candidate second generation planetary systems, including Gl 86, HD 27442 and all of the

  19. A Quantitative Approach to Assessing System Evolvability

    NASA Technical Reports Server (NTRS)

    Christian, John A., III

    2004-01-01

    When selecting a system from multiple candidates, the customer seeks the one that best meets his or her needs. Recently the desire for evolvable systems has become more important and engineers are striving to develop systems that accommodate this need. In response to this search for evolvability, we present a historical perspective on evolvability, propose a refined definition of evolvability, and develop a quantitative method for measuring this property. We address this quantitative methodology from both a theoretical and practical perspective. This quantitative model is then applied to the problem of evolving a lunar mission to a Mars mission as a case study.

  20. Recommendation in evolving online networks

    NASA Astrophysics Data System (ADS)

    Hu, Xiao; Zeng, An; Shang, Ming-Sheng

    2016-02-01

    Recommender system is an effective tool to find the most relevant information for online users. By analyzing the historical selection records of users, recommender system predicts the most likely future links in the user-item network and accordingly constructs a personalized recommendation list for each user. So far, the recommendation process is mostly investigated in static user-item networks. In this paper, we propose a model which allows us to examine the performance of the state-of-the-art recommendation algorithms in evolving networks. We find that the recommendation accuracy in general decreases with time if the evolution of the online network fully depends on the recommendation. Interestingly, some randomness in users' choice can significantly improve the long-term accuracy of the recommendation algorithm. When a hybrid recommendation algorithm is applied, we find that the optimal parameter gradually shifts towards the diversity-favoring recommendation algorithm, indicating that recommendation diversity is essential to keep a high long-term recommendation accuracy. Finally, we confirm our conclusions by studying the recommendation on networks with the real evolution data.

  1. Multiscale modelling of evolving foams

    NASA Astrophysics Data System (ADS)

    Saye, R. I.; Sethian, J. A.

    2016-06-01

    We present a set of multi-scale interlinked algorithms to model the dynamics of evolving foams. These algorithms couple the key effects of macroscopic bubble rearrangement, thin film drainage, and membrane rupture. For each of the mechanisms, we construct consistent and accurate algorithms, and couple them together to work across the wide range of space and time scales that occur in foam dynamics. These algorithms include second order finite difference projection methods for computing incompressible fluid flow on the macroscale, second order finite element methods to solve thin film drainage equations in the lamellae and Plateau borders, multiphase Voronoi Implicit Interface Methods to track interconnected membrane boundaries and capture topological changes, and Lagrangian particle methods for conservative liquid redistribution during rearrangement and rupture. We derive a full set of numerical approximations that are coupled via interface jump conditions and flux boundary conditions, and show convergence for the individual mechanisms. We demonstrate our approach by computing a variety of foam dynamics, including coupled evolution of three-dimensional bubble clusters attached to an anchored membrane and collapse of a foam cluster.

  2. Submillimeter observations of evolved stars

    SciTech Connect

    Sopka, R.J.; Hildebrand, R.; Jaffe, D.T.; Gatley, I.; Roellig, T.; Werner, M.; Jura, M.; Zuckerman, B.

    1985-07-01

    Broad-band submillimeter observations of the thermal emission from evolved stars have been obtained with the United Kingdom Infrared Telescope on Mauna Kea, Hawaii. These observations, at an effective wavelength of 400 ..mu..m, provide the most direct method for estimating the mass loss rate in dust from these stars and also help to define the long-wavelength thermal spectrum of the dust envelopes. The mass loss rates in dust that we derive range from 10/sup -9/ to 10/sup -6/ M/sub sun/ yr/sup -1/ and are compared with mass loss rates derived from molecular line observations to estimate gas-to-dust ratios in outflowing envelopes. These values are found to be generally compatible with the interstellar gas-to-dust ratio of approx.100 if submillimeter emissivities appropriate to amorphous grain structures are assumed. Our analysis of the spectrum of IRC+10216 confirms previous suggestions that the grain emissivity varies as lambda/sup -1.2/ rather than as lambda/sup -2/ for 10

  3. Voyages Through Time: Everything Evolves

    NASA Astrophysics Data System (ADS)

    Pendleton, Y. J.; Tarter, J. C.; DeVore, E. K.; O'Sullivan, K. A.; Taylor, S. M.

    2001-12-01

    Evolutionary change is a powerful framework for studying our world and our place therein. It is a recurring theme in every realm of science: over time, the universe, the planet Earth, life, and human technologies all change, albeit on vastly different scales. Evolution offers scientific explanations for the age-old question, "Where did we come from?" In addition, historical perspectives of science show how our understanding has evolved over time. The complexities of all of these systems will never reveal a "finished" story. But it is a story of epic size, capable of inspiring awe and of expanding our sense of time and place, and eminently worthy of investigating. This story is the basis of Voyages Through Time. Voyages Through Time (VTT), provides teachers with not only background science content and pedagogy, but also with materials and resources for the teaching of evolution. The six modules, Cosmic Evolution, Planetary Evolution, Origin of Life, Evolution of Life, Hominid Evolution, and Evolution of Technology, emphasize student inquiry, and promote the nature of science, as recommended in the NSES and BSL. The modules are unified by the overarching theme of evolution and the meta questions: "What is changing?" "What is the rate of change?" and "What is the mechanism of change?" Determination of student outcomes for the project required effective collaboration of scientists, teachers, students and media specialists. The broadest curricula students outcomes are 1) an enjoyment of science, 2) an understanding of the nature of science, especially the understanding of evidence and re-evaluation, and 3) key science content. The curriculum is being developed by the SETI Institute, NASA Ames Research Center, California Academy of Sciences, and San Francisco State University, and is funded by the NSF (IMD 9730693), with support form Hewlett-Packard Company, The Foundation for Microbiology, Combined Federated Charities, NASA Astrobiology Institute, and NASA Fundamental

  4. A slowly evolving host moves first in symbiotic interactions

    NASA Astrophysics Data System (ADS)

    Damore, James; Gore, Jeff

    2011-03-01

    Symbiotic relationships, both parasitic and mutualistic, are ubiquitous in nature. Understanding how these symbioses evolve, from bacteria and their phages to humans and our gut microflora, is crucial in understanding how life operates. Often, symbioses consist of a slowly evolving host species with each host only interacting with its own sub-population of symbionts. The Red Queen hypothesis describes coevolutionary relationships as constant arms races with each species rushing to evolve an advantage over the other, suggesting that faster evolution is favored. Here, we use a simple game theoretic model of host- symbiont coevolution that includes population structure to show that if the symbionts evolve much faster than the host, the equilibrium distribution is the same as it would be if it were a sequential game where the host moves first against its symbionts. For the slowly evolving host, this will prove to be advantageous in mutualisms and a handicap in antagonisms. The model allows for symbiont adaptation to its host, a result that is robust to changes in the parameters and generalizes to continuous and multiplayer games. Our findings provide insight into a wide range of symbiotic phenomena and help to unify the field of coevolutionary theory.

  5. What Technology? Reflections on Evolving Services

    ERIC Educational Resources Information Center

    Collins, Sharon

    2009-01-01

    Each year, the members of the EDUCAUSE Evolving Technologies Committee identify and research the evolving technologies that are having--or are predicted to have--the most direct impact on higher education institutions. The committee members choose the relevant topics, write white papers, and present their findings at the EDUCAUSE annual…

  6. Extreme insular dwarfism evolved in a mammoth.

    PubMed

    Herridge, Victoria L; Lister, Adrian M

    2012-08-22

    The insular dwarfism seen in Pleistocene elephants has come to epitomize the island rule; yet our understanding of this phenomenon is hampered by poor taxonomy. For Mediterranean dwarf elephants, where the most extreme cases of insular dwarfism are observed, a key systematic question remains unresolved: are all taxa phyletic dwarfs of a single mainland species Palaeoloxodon antiquus (straight-tusked elephant), or are some referable to Mammuthus (mammoths)? Ancient DNA and geochronological evidence have been used to support a Mammuthus origin for the Cretan 'Palaeoloxodon' creticus, but these studies have been shown to be flawed. On the basis of existing collections and recent field discoveries, we present new, morphological evidence for the taxonomic status of 'P'. creticus, and show that it is indeed a mammoth, most probably derived from Early Pleistocene Mammuthus meridionalis or possibly Late Pliocene Mammuthus rumanus. We also show that Mammuthus creticus is smaller than other known insular dwarf mammoths, and is similar in size to the smallest dwarf Palaeoloxodon species from Sicily and Malta, making it the smallest mammoth species known to have existed. These findings indicate that extreme insular dwarfism has evolved to a similar degree independently in two elephant lineages.

  7. Extreme insular dwarfism evolved in a mammoth.

    PubMed

    Herridge, Victoria L; Lister, Adrian M

    2012-08-22

    The insular dwarfism seen in Pleistocene elephants has come to epitomize the island rule; yet our understanding of this phenomenon is hampered by poor taxonomy. For Mediterranean dwarf elephants, where the most extreme cases of insular dwarfism are observed, a key systematic question remains unresolved: are all taxa phyletic dwarfs of a single mainland species Palaeoloxodon antiquus (straight-tusked elephant), or are some referable to Mammuthus (mammoths)? Ancient DNA and geochronological evidence have been used to support a Mammuthus origin for the Cretan 'Palaeoloxodon' creticus, but these studies have been shown to be flawed. On the basis of existing collections and recent field discoveries, we present new, morphological evidence for the taxonomic status of 'P'. creticus, and show that it is indeed a mammoth, most probably derived from Early Pleistocene Mammuthus meridionalis or possibly Late Pliocene Mammuthus rumanus. We also show that Mammuthus creticus is smaller than other known insular dwarf mammoths, and is similar in size to the smallest dwarf Palaeoloxodon species from Sicily and Malta, making it the smallest mammoth species known to have existed. These findings indicate that extreme insular dwarfism has evolved to a similar degree independently in two elephant lineages. PMID:22572206

  8. Evolving Magnetic Structures and Their Relation to Coronal Mass Ejections

    NASA Technical Reports Server (NTRS)

    Feynman, J.

    1996-01-01

    Solar activity regions are frequently concentrated into cluster which persist for many solar rotations. These activity complexes are associated with weak dispersed magnetic fields which are most apparent after the activity itself has ceased. We call this combination of persistent activity and dispersed Evolving Magnetic Structures (EMS). Here we show examples of EMSs and describe the evolution of an EMS associated with major Coronal Mass Ejections (CME) and other solar and magnetic disturbances.

  9. Memristive Physically Evolving Networks Enabling the Emulation of Heterosynaptic Plasticity.

    PubMed

    Yang, Yuchao; Chen, Bing; Lu, Wei D

    2015-12-16

    A nanoscale, solid-state physically evolving network is experimentally demonstrated, based on the self-organization of Ag nanoclusters under an electric field. The adaptive nature of the network is determined by the collective inputs from multiple terminals and allows the emulation of heterosynaptic plasticity, an important learning rule in biological systems. These effects are universally observed in devices based on different switching materials. PMID:26484746

  10. What to Expect From the Evolving Field of Geriatric Cardiology.

    PubMed

    Bell, Susan P; Orr, Nicole M; Dodson, John A; Rich, Michael W; Wenger, Nanette K; Blum, Kay; Harold, John Gordon; Tinetti, Mary E; Maurer, Mathew S; Forman, Daniel E

    2015-09-15

    The population of older adults is expanding rapidly, and aging predisposes to cardiovascular disease. The principle of patient-centered care must respond to the preponderance of cardiac disease that now occurs in combination with the complexities of old age. Geriatric cardiology melds cardiovascular perspectives with multimorbidity, polypharmacy, frailty, cognitive decline, and other clinical, social, financial, and psychological dimensions of aging. Although some assume that a cardiologist may instinctively cultivate some of these skills over the course of a career, we assert that the volume and complexity of older cardiovascular patients in contemporary practice warrants a more direct approach to achieve suitable training and a more reliable process of care. We present a rationale and vision for geriatric cardiology as a melding of primary cardiovascular and geriatrics skills, thereby infusing cardiology practice with expanded proficiencies in diagnosis, risks, care coordination, communications, end-of-life, and other competences required to best manage older cardiovascular patients.

  11. Theories of Aging: An Ever-Evolving Field

    PubMed Central

    Sergiev, P. V.; Dontsova, O. A.; Berezkin, G. V.

    2015-01-01

    Senescence has been the focus of research for many centuries. Despite significant progress in extending average human life expectancy, the process of aging remains largely elusive and, unfortunately, inevitable. In this review, we attempted to summarize the current theories of aging and the approaches to understanding it. PMID:25926998

  12. Gut Microbiota and Brain Function: An Evolving Field in Neuroscience.

    PubMed

    Foster, Jane A; Lyte, Mark; Meyer, Emeran; Cryan, John F

    2016-05-01

    There is a growing appreciation of the importance of gut microbiota to health and disease. This has been driven by advances in sequencing technology and recent findings demonstrating the important role of microbiota in common health disorders such as obesity. Moreover, the potential role of gut microbiota in influencing brain function, behavior, and mental health has attracted the attention of neuroscientists and psychiatrists. At the 29(th) International College of Neuropsychopharmacology (CINP) World Congress held in Vancouver, Canada, in June 2014, a group of experts presented the symposium, "Gut microbiota and brain function: Relevance to psychiatric disorders" to review the latest findings in how gut microbiota may play a role in brain function, behavior, and disease. The symposium covered a broad range of topics, including gut microbiota and neuroendocrine function, the influence of gut microbiota on behavior, probiotics as regulators of brain and behavior, and imaging the gut-brain axis in humans. This report provides an overview of these presentations. PMID:26438800

  13. Gut Microbiota and Brain Function: An Evolving Field in Neuroscience

    PubMed Central

    Lyte, Mark; Meyer, Emeran; Cryan, John F

    2016-01-01

    There is a growing appreciation of the importance of gut microbiota to health and disease. This has been driven by advances in sequencing technology and recent findings demonstrating the important role of microbiota in common health disorders such as obesity. Moreover, the potential role of gut microbiota in influencing brain function, behavior, and mental health has attracted the attention of neuroscientists and psychiatrists. At the 29th International College of Neuropsychopharmacology (CINP) World Congress held in Vancouver, Canada, in June 2014, a group of experts presented the symposium, “Gut microbiota and brain function: Relevance to psychiatric disorders” to review the latest findings in how gut microbiota may play a role in brain function, behavior, and disease. The symposium covered a broad range of topics, including gut microbiota and neuroendocrine function, the influence of gut microbiota on behavior, probiotics as regulators of brain and behavior, and imaging the gut-brain axis in humans. This report provides an overview of these presentations. PMID:26438800

  14. Towards Evolving Electronic Circuits for Autonomous Space Applications

    NASA Technical Reports Server (NTRS)

    Lohn, Jason D.; Haith, Gary L.; Colombano, Silvano P.; Stassinopoulos, Dimitris

    2000-01-01

    The relatively new field of Evolvable Hardware studies how simulated evolution can reconfigure, adapt, and design hardware structures in an automated manner. Space applications, especially those requiring autonomy, are potential beneficiaries of evolvable hardware. For example, robotic drilling from a mobile platform requires high-bandwidth controller circuits that are difficult to design. In this paper, we present automated design techniques based on evolutionary search that could potentially be used in such applications. First, we present a method of automatically generating analog circuit designs using evolutionary search and a circuit construction language. Our system allows circuit size (number of devices), circuit topology, and device values to be evolved. Using a parallel genetic algorithm, we present experimental results for five design tasks. Second, we investigate the use of coevolution in automated circuit design. We examine fitness evaluation by comparing the effectiveness of four fitness schedules. The results indicate that solution quality is highest with static and co-evolving fitness schedules as compared to the other two dynamic schedules. We discuss these results and offer two possible explanations for the observed behavior: retention of useful information, and alignment of problem difficulty with circuit proficiency.

  15. Interactions between planets and evolved stars

    NASA Astrophysics Data System (ADS)

    Shengbang, Qian; Zhongtao, Han; Fernández Lajús, E.; liying, Zhu; Wenping, Liao; Miloslav, Zejda; Linjia, Li; Voloshina, Irina; Liang, Liu; Jiajia., He

    2016-07-01

    Searching for planetary companions to evolved stars (e.g., white dwarfs (WD) and Cataclysmic Variables (CV)) can provide insight into the interaction between planets and evolved stars as well as on the ultimate fate of planets. We have monitored decades of CVs and their progenitors including some detached WD binaries since 2006 to search for planets orbiting these systems. In the present paper, we will show some observational results of circumbinary planets in orbits around CVs and their progenitors. Some of our findings include planets with the shortest distance to the central evolved binaries and a few multiple planetary systems orbiting binary stars. Finally, by comparing the observational properties of planetary companions to single WDs and WD binaries, the interaction between planets and evolved stars and the ultimate fate of planets are discussed.

  16. Neural mechanisms underlying the evolvability of behaviour

    PubMed Central

    Katz, Paul S.

    2011-01-01

    The complexity of nervous systems alters the evolvability of behaviour. Complex nervous systems are phylogenetically constrained; nevertheless particular species-specific behaviours have repeatedly evolved, suggesting a predisposition towards those behaviours. Independently evolved behaviours in animals that share a common neural architecture are generally produced by homologous neural structures, homologous neural pathways and even in the case of some invertebrates, homologous identified neurons. Such parallel evolution has been documented in the chromatic sensitivity of visual systems, motor behaviours and complex social behaviours such as pair-bonding. The appearance of homoplasious behaviours produced by homologous neural substrates suggests that there might be features of these nervous systems that favoured the repeated evolution of particular behaviours. Neuromodulation may be one such feature because it allows anatomically defined neural circuitry to be re-purposed. The developmental, genetic and physiological mechanisms that contribute to nervous system complexity may also bias the evolution of behaviour, thereby affecting the evolvability of species-specific behaviour. PMID:21690127

  17. Laboratory and field efficacy of entomopathogenic fungi for the management of the sweetpotato weevil, Cylas formicarius (Coleoptera: Brentidae).

    PubMed

    Reddy, Gadi V P; Zhao, Zihua; Humber, Richard A

    2014-10-01

    The sweetpotato weevil, Cylas formicarius (F.) (Coleoptera: Brentidae), is one of the most important pests of sweet potatoes in the world. With free trade between the United States and the U.S.-controlled Mariana Islands, C. formicarius has spread along with this commodity. Because of the cryptic nature of the larvae and nocturnal activity of the adults, and the cancellation of long-residual pesticides, this pest has become increasingly difficult to control. Therefore, the present study sought to explore and to compare the effectiveness of Metarhizium brunneum F52 (90ml a.i./ha), Beauveria bassiana GHA (40ml a.i./ha), spinosad (90g a.i./ha), azadirachtin (1484ml a.i./ha), B. bassiana+M. brunneum (20ml a.i./ha+45ml a.i./ha), B. bassiana+azadirachtin (20ml a.i./ha+742ml a.i./ha), B. bassiana+spinosad (20ml a.i./ha+45ml a.i./ha), M. brunneum+azadirachtin (45ml a.i./ha+742ml a.i./ha) and M. brunneum+spinosad (45ml a.i./ha+45 grams a.i./ha) in controlling this pest in both the laboratory and the field. The treatment with B. bassiana+M. brunneum was the most effective in reducing tuber damage by C. formicarius, producing the highest yields. The most adult cadavers were found in plots treated with the combination of two fungi. This combined fungal formulation appears to be appropriate for the practical control of C. formicarius on sweet potatoes. PMID:25111763

  18. Laboratory and field efficacy of entomopathogenic fungi for the management of the sweetpotato weevil, Cylas formicarius (Coleoptera: Brentidae).

    PubMed

    Reddy, Gadi V P; Zhao, Zihua; Humber, Richard A

    2014-10-01

    The sweetpotato weevil, Cylas formicarius (F.) (Coleoptera: Brentidae), is one of the most important pests of sweet potatoes in the world. With free trade between the United States and the U.S.-controlled Mariana Islands, C. formicarius has spread along with this commodity. Because of the cryptic nature of the larvae and nocturnal activity of the adults, and the cancellation of long-residual pesticides, this pest has become increasingly difficult to control. Therefore, the present study sought to explore and to compare the effectiveness of Metarhizium brunneum F52 (90ml a.i./ha), Beauveria bassiana GHA (40ml a.i./ha), spinosad (90g a.i./ha), azadirachtin (1484ml a.i./ha), B. bassiana+M. brunneum (20ml a.i./ha+45ml a.i./ha), B. bassiana+azadirachtin (20ml a.i./ha+742ml a.i./ha), B. bassiana+spinosad (20ml a.i./ha+45ml a.i./ha), M. brunneum+azadirachtin (45ml a.i./ha+742ml a.i./ha) and M. brunneum+spinosad (45ml a.i./ha+45 grams a.i./ha) in controlling this pest in both the laboratory and the field. The treatment with B. bassiana+M. brunneum was the most effective in reducing tuber damage by C. formicarius, producing the highest yields. The most adult cadavers were found in plots treated with the combination of two fungi. This combined fungal formulation appears to be appropriate for the practical control of C. formicarius on sweet potatoes.

  19. Evolving physically simulated flying creatures for efficient cruising.

    PubMed

    Shim, Yoon-Sik; Kim, Chang-Hun

    2006-01-01

    The body-brain coevolution of aerial life forms has not been developed as far as aquatic or terrestrial locomotion in the field of artificial life. We are studying physically simulated 3D flying creatures by evolving both wing shapes and their controllers. A creature's wing is modeled as a number of articulated cylinders, connected by triangular films (patagia). The wing structure and its motor controllers for cruising flight are generated by an evolutionary algorithm within a simulated aerodynamic environment. The most energy-efficient cruising speed and the lift and drag coefficients of each flier are calculated from its morphological characteristics and used in the fitness evaluation. To observe a wide range of creature size, the evolution is run separately for creatures categorized into three species by body weight. The resulting creatures vary in size from pigeons to pterosaurs, with various wing configurations. We discuss the characteristics of shape and motion of the evolved creatures, including flight stability and Strouhal number.

  20. Evolving Approaches to the Ethical Management of Genomic Data

    PubMed Central

    Boyer, Joy T.; Sun, Kathie Y.

    2013-01-01

    The ethical landscape in the field of genomics is rapidly shifting. Plummeting sequencing costs, along with ongoing advances in bioinformatics, now make it possible to generate an enormous volume of genomic data about vast numbers of people. The informational richness, complexity, and frequently uncertain meaning of these data, coupled with evolving norms surrounding the sharing of data and samples and persistent privacy concerns, have generated a range of approaches to the ethical management of genomic information. As calls increase for the expanded use of broad or even open consent, and as controversy grows about how best to handle incidental genomic findings, these approaches, informed by normative analysis and empirical data, will continue to evolve alongside the science. PMID:23453621

  1. The evolving magnetic topology of τ Boötis

    NASA Astrophysics Data System (ADS)

    Mengel, M. W.; Fares, R.; Marsden, S. C.; Carter, B. D.; Jeffers, S. V.; Petit, P.; Donati, J.-F.; Folsom, C. P.; BCool Collaboration

    2016-07-01

    We present six epochs of spectropolarimetric observations of the hot-Jupiter-hosting star τ Boötis that extend the exceptional previous multiyear data set of its large-scale magnetic field. Our results confirm that the large-scale magnetic field of τ Boötis varies cyclicly, with the observation of two further magnetic reversals; between 2013 December and 2014 May and between 2015 January and March. We also show that the field evolves in a broadly solar-type manner in contrast to other F-type stars. We further present new results which indicate that the chromospheric activity cycle and the magnetic activity cycles are related, which would indicate a very rapid magnetic cycle. As an exemplar of long-term magnetic field evolution, τ Boötis and this long-term monitoring campaign presents a unique opportunity for studying stellar magnetic cycles.

  2. BUBBLE DYNAMICS AT GAS-EVOLVING ELECTRODES

    SciTech Connect

    Sides, Paul J.

    1980-12-01

    Nucleation of bubbles, their growth by diffusion of dissolved gas to the bubble surface and by coalescence, and their detachment from the electrode are all very fast phenomena; furthermore, electrolytically generated bubbles range in size from ten to a few hundred microns; therefore, magnification and high speed cinematography are required to observe bubbles and the phenomena of their growth on the electrode surface. Viewing the action from the front side (the surface on which the bubbles form) is complicated because the most important events occur close to the surface and are obscured by other bubbles passing between the camera and the electrode; therefore, oxygen was evolved on a transparent tin oxide "window" electrode and the events were viewed from the backside. The movies showed that coalescence of bubbles is very important for determining the size of bubbles and in the chain of transport processes; growth by diffusion and by coalescence proceeds in series and parallel; coalescing bubbles cause significant fluid motion close to the electrode; bubbles can leave and reattach; and bubbles evolve in a cycle of growth by diffusion and different modes of coalescence. An analytical solution for the primary potential and current distribution around a spherical bubble in contact with a plane electrode is presented. Zero at the contact point, the current density reaches only one percent of its undisturbed value at 30 percent of the radius from that point and goes through a shallow maximum two radii away. The solution obtained for spherical bubbles is shown to apply for the small bubbles of electrolytic processes. The incremental resistance in ohms caused by sparse arrays of bubbles is given by {Delta}R = 1.352 af/kS where f is the void fraction of gas in the bubble layer, a is the bubble layer thickness, k is the conductivity of gas free electrolyte, and S is the electrode area. A densely populated gas bubble layer on an electrode was modeled as a hexagonal array of

  3. A magnetically collimated jet from an evolved star.

    PubMed

    Vlemmings, Wouter H T; Diamond, Philip J; Imai, Hiroshi

    2006-03-01

    Planetary nebulae often have asymmetric shapes, even though their progenitor stars were symmetric; this structure could be the result of collimated jets from the evolved stars before they enter the planetary nebula phase. Theoretical models have shown that magnetic fields could be the dominant source of jet-collimation in evolved stars, just as these fields are thought to collimate outflows in other astrophysical sources, such as active galactic nuclei and proto-stars. But hitherto there have been no direct observations of both the magnetic field direction and strength in any collimated jet. Here we report measurements of the polarization of water vapour masers that trace the precessing jet emanating from the asymptotic giant branch star W43A (at a distance of 2.6 kpc from the Sun), which is undergoing rapid evolution into a planetary nebula. The masers occur in two clusters at opposing tips of the jets, approximately 1,000 au from the star. We conclude from the data that the magnetic field is indeed collimating the jet. PMID:16511488

  4. Quantifying evolvability in small biological networks

    SciTech Connect

    Nemenman, Ilya; Mugler, Andrew; Ziv, Etay; Wiggins, Chris H

    2008-01-01

    The authors introduce a quantitative measure of the capacity of a small biological network to evolve. The measure is applied to a stochastic description of the experimental setup of Guet et al. (Science 2002, 296, pp. 1466), treating chemical inducers as functional inputs to biochemical networks and the expression of a reporter gene as the functional output. The authors take an information-theoretic approach, allowing the system to set parameters that optimise signal processing ability, thus enumerating each network's highest-fidelity functions. All networks studied are highly evolvable by the measure, meaning that change in function has little dependence on change in parameters. Moreover, each network's functions are connected by paths in the parameter space along which information is not significantly lowered, meaning a network may continuously change its functionality without completely losing it along the way. This property further underscores the evolvability of the networks.

  5. Metanetworks of artificially evolved regulatory networks

    NASA Astrophysics Data System (ADS)

    Danacı, Burçin; Erzan, Ayşe

    2016-04-01

    We study metanetworks arising in genotype and phenotype spaces, in the context of a model population of Boolean graphs evolved under selection for short dynamical attractors. We define the adjacency matrix of a graph as its genotype, which gets mutated in the course of evolution, while its phenotype is its set of dynamical attractors. Metanetworks in the genotype and phenotype spaces are formed, respectively, by genetic proximity and by phenotypic similarity, the latter weighted by the sizes of the basins of attraction of the shared attractors. We find that evolved populations of Boolean graphs form tree-like giant clusters in genotype space, while random populations of Boolean graphs are typically so far removed from each other genetically that they cannot form a metanetwork. In phenotype space, the metanetworks of evolved populations are super robust both under the elimination of weak connections and random removal of nodes.

  6. Reliability of genetic networks is evolvable

    NASA Astrophysics Data System (ADS)

    Braunewell, Stefan; Bornholdt, Stefan

    2008-06-01

    Control of the living cell functions with remarkable reliability despite the stochastic nature of the underlying molecular networks—a property presumably optimized by biological evolution. We ask here to what extent the ability of a stochastic dynamical network to produce reliable dynamics is an evolvable trait. Using an evolutionary algorithm based on a deterministic selection criterion for the reliability of dynamical attractors, we evolve networks of noisy discrete threshold nodes. We find that, starting from any random network, reliability of the attractor landscape can often be achieved with only a few small changes to the network structure. Further, the evolvability of networks toward reliable dynamics while retaining their function is investigated and a high success rate is found.

  7. JavaGenes: Evolving Graphs with Crossover

    NASA Technical Reports Server (NTRS)

    Globus, Al; Atsatt, Sean; Lawton, John; Wipke, Todd

    2000-01-01

    Genetic algorithms usually use string or tree representations. We have developed a novel crossover operator for a directed and undirected graph representation, and used this operator to evolve molecules and circuits. Unlike strings or trees, a single point in the representation cannot divide every possible graph into two parts, because graphs may contain cycles. Thus, the crossover operator is non-trivial. A steady-state, tournament selection genetic algorithm code (JavaGenes) was written to implement and test the graph crossover operator. All runs were executed by cycle-scavagging on networked workstations using the Condor batch processing system. The JavaGenes code has evolved pharmaceutical drug molecules and simple digital circuits. Results to date suggest that JavaGenes can evolve moderate sized drug molecules and very small circuits in reasonable time. The algorithm has greater difficulty with somewhat larger circuits, suggesting that directed graphs (circuits) are more difficult to evolve than undirected graphs (molecules), although necessary differences in the crossover operator may also explain the results. In principle, JavaGenes should be able to evolve other graph-representable systems, such as transportation networks, metabolic pathways, and computer networks. However, large graphs evolve significantly slower than smaller graphs, presumably because the space-of-all-graphs explodes combinatorially with graph size. Since the representation strongly affects genetic algorithm performance, adding graphs to the evolutionary programmer's bag-of-tricks should be beneficial. Also, since graph evolution operates directly on the phenotype, the genotype-phenotype translation step, common in genetic algorithm work, is eliminated.

  8. A Stefan problem on an evolving surface

    PubMed Central

    Alphonse, Amal; Elliott, Charles M.

    2015-01-01

    We formulate a Stefan problem on an evolving hypersurface and study the well posedness of weak solutions given L1 data. To do this, we first develop function spaces and results to handle equations on evolving surfaces in order to give a natural treatment of the problem. Then, we consider the existence of solutions for data; this is done by regularization of the nonlinearity. The regularized problem is solved by a fixed point theorem and then uniform estimates are obtained in order to pass to the limit. By using a duality method, we show continuous dependence, which allows us to extend the results to L1 data. PMID:26261364

  9. How the first biopolymers could have evolved.

    PubMed Central

    Abkevich, V I; Gutin, A M; Shakhnovich, E I

    1996-01-01

    In this work, we discuss a possible origin of the first biopolymers with stable unique structures. We suggest that at the prebiotic stage of evolution, long organic polymers had to be compact to avoid hydrolysis and had to be soluble and thus must not be exceedingly hydrophobic. We present an algorithm that generates such sequences for model proteins. The evolved sequences turn out to have a stable unique structure, into which they quickly fold. This result illustrates the idea that the unique three-dimensional native structures of first biopolymers could have evolved as a side effect of nonspecific physicochemical factors acting at the prebiotic stage of evolution. PMID:8570645

  10. Surveying The Digital Landscape: Evolving Technologies 2004. The EDUCAUSE Evolving Technologies Committee

    ERIC Educational Resources Information Center

    EDUCAUSE Review, 2004

    2004-01-01

    Each year, the members of the EDUCAUSE Evolving Technologies Committee identify and research the evolving technologies that are having the most direct impact on higher education institutions. The committee members choose the relevant topics, write white papers, and present their findings at the EDUCAUSE annual conference. This year, under the…

  11. Higher rates of sex evolve in spatially heterogeneous environments.

    PubMed

    Becks, Lutz; Agrawal, Aneil F

    2010-11-01

    The evolution and maintenance of sexual reproduction has puzzled biologists for decades. Although this field is rich in hypotheses, experimental evidence is scarce. Some important experiments have demonstrated differences in evolutionary rates between sexual and asexual populations; other experiments have documented evolutionary changes in phenomena related to genetic mixing, such as recombination and selfing. However, direct experiments of the evolution of sex within populations are extremely rare (but see ref. 12). Here we use the rotifer, Brachionus calyciflorus, which is capable of both sexual and asexual reproduction, to test recent theory predicting that there is more opportunity for sex to evolve in spatially heterogeneous environments. Replicated experimental populations of rotifers were maintained in homogeneous environments, composed of either high- or low-quality food habitats, or in heterogeneous environments that consisted of a mix of the two habitats. For populations maintained in either type of homogeneous environment, the rate of sex evolves rapidly towards zero. In contrast, higher rates of sex evolve in populations experiencing spatially heterogeneous environments. The data indicate that the higher level of sex observed under heterogeneity is not due to sex being less costly or selection against sex being less efficient; rather sex is sufficiently advantageous in heterogeneous environments to overwhelm its inherent costs. Counter to some alternative theories for the evolution of sex, there is no evidence that genetic drift plays any part in the evolution of sex in these populations.

  12. Project Evolve User-Adopter Manual.

    ERIC Educational Resources Information Center

    Joiner, Lee M.

    An adult basic education (ABE) program for mentally retarded young adults between the ages of 14 and 26 years, Project Evolve can provide education agencies for educationally handicapped children with detailed information concerning an innovative program. The manual format was developed through interviews with professional educators concerning the…

  13. A Course Evolves-Physical Anthropology.

    ERIC Educational Resources Information Center

    O'Neil, Dennis

    2001-01-01

    Describes the development of an online physical anthropology course at Palomar College (California) that evolved from online tutorials. Discusses the ability to update materials on the Web more quickly than in traditional textbooks; creating Web pages that are readable by most Web browsers; test security issues; and clarifying ownership of online…

  14. Hyper massive black holes in evolved galaxies

    NASA Astrophysics Data System (ADS)

    Romero-Cruz, Fernando J.

    2015-09-01

    From the SDSS DR7 we took a sample of 16733 galaxies which do not show all of the emission lines required to classify their activity according to the classical BPT diagram (Baldwin et al. 1981 PASP). Since they do not show these emission lines they are thought to be evolved enough so to host Hyper Massive Black holes. We compared their statistical properties with other galaxies from the SDSS DR7 which do show emission lines and confirmed that their M-sigma relationship correspond to HMBHs (Gutelkin et al. 2009 ApJ) and also that their SFH confirms evolution. We also analyzed them with a new Diagnostic Diagram in the IR (Coziol et al. 2015 AJ) and found that their position in the IR color space (W3W4 vs W2W3) correspond to AGN activity with current low SF, another confirmation of an evolved galaxy. The position of our final sample in the IR diagram is in the same region in which Holm 15A lies, this galaxy is considered to host the most massive BHs in the nearby universe (Lopez-Cruz et al. 2014 ApJL). The morphology of these galaxies (all of them are classified as elliptical) confirms that they are very evolved. We claim that the hyper massive BH lie in galaxies very evolved and with very low SF and without clear AGN activity in the BPT diagram.

  15. Evolving dimensions in medical case reporting

    PubMed Central

    2011-01-01

    Medical case reports (MCRs) have been undervalued in the literature to date. It seems that while case series emphasize what is probable, case reports describe what is possible and what can go wrong. MCRs transfer medical knowledge and act as educational tools. We outline evolving aspects of the MCR in current practice. PMID:21524284

  16. Antibody therapeutics - the evolving patent landscape.

    PubMed

    Petering, Jenny; McManamny, Patrick; Honeyman, Jane

    2011-09-01

    The antibody patent landscape has evolved dramatically over the past 30 years, particularly in areas of technology relating to antibody modification to reduce immunogenicity in humans or improve antibody function. In some cases antibody techniques that were developed in the 1980s are still the subject of patent protection in the United States or Canada.

  17. The Evolving Office of the Registrar

    ERIC Educational Resources Information Center

    Pace, Harold L.

    2011-01-01

    A healthy registrar's office will continue to evolve as it considers student, faculty, and institutional needs; staff talents and expectations; technological opportunities; economic realities; space issues; work environments; and where the strategic plan is taking the institution in support of the mission. Several recognized leaders in the field…

  18. Apollo 16 Evolved Lithology Sodic Ferrogabbro

    NASA Technical Reports Server (NTRS)

    Zeigler, Ryan; Jolliff, B. L.; Korotev, R. L.

    2014-01-01

    Evolved lunar igneous lithologies, often referred to as the alkali suite, are a minor but important component of the lunar crust. These evolved samples are incompatible-element rich samples, and are, not surprisingly, most common in the Apollo sites in (or near) the incompatible-element rich region of the Moon known as the Procellarum KREEP Terrane (PKT). The most commonly occurring lithologies are granites (A12, A14, A15, A17), monzogabbro (A14, A15), alkali anorthosites (A12, A14), and KREEP basalts (A15, A17). The Feldspathic Highlands Terrane is not entirely devoid of evolved lithologies, and rare clasts of alkali gabbronorite and sodic ferrogabbro (SFG) have been identified in Apollo 16 station 11 breccias 67915 and 67016. Curiously, nearly all pristine evolved lithologies have been found as small clasts or soil particles, exceptions being KREEP basalts 15382/6 and granitic sample 12013 (which is itself a breccia). Here we reexamine the petrography and geochemistry of two SFG-like particles found in a survey of Apollo 16 2-4 mm particles from the Cayley Plains 62283,7-15 and 62243,10-3 (hereafter 7-15 and 10-3 respectively). We will compare these to previously reported SFG samples, including recent analyses on the type specimen of SFG from lunar breccia 67915.

  19. Numerical Simulation of a Spatially Evolving Supersonic Turbulent Boundary Layer

    NASA Technical Reports Server (NTRS)

    Gatski, T. B.; Erlebacher, G.

    2002-01-01

    The results from direct numerical simulations of a spatially evolving, supersonic, flat-plate turbulent boundary-layer flow, with free-stream Mach number of 2.25 are presented. The simulated flow field extends from a transition region, initiated by wall suction and blowing near the inflow boundary, into the fully turbulent regime. Distributions of mean and turbulent flow quantities are obtained and an analysis of these quantities is performed at a downstream station corresponding to Re(sub x)= 5.548 x10(exp 6) based on distance from the leading edge.

  20. 2009 Arctic Mars Analogue Svalbard Expedition (AMASE) Evolved Gas Studies

    NASA Astrophysics Data System (ADS)

    Mahaffy, P. R.; McAdam, A.; Eigenbrode, J.; Steele, A.

    2009-12-01

    The Arctic Mars Analogue Svalbard Expedition (AMASE) continued its multi-year campaign in August 2009 to study selected sedimentary and igneous environments in this geological diverse archipelago using a variety of measurement techniques and protocols that are candidates for future Mars missions. The X-ray diffraction mineralogical and evolved gas analysis (EGA) employed during the AMASE-2009 campaign closely mimicked similar experiments that are planned for the 2011 Mars Science Laboratory (MSL). Field instruments similar to those under development for the ESA ExoMars or other rover missions provided imaging, spectroscopic, and subsurface sounding data. A variety of microbiology and field life detection techniques rounded out the AMASE-2009 analytical tools. The evolved gas mass spectrometer utilized on AMASE-2009 was designed to model elements of the Sample Analysis at Mars (SAM) suite of instruments on MSL. Powdered rock samples were heated from ambient to 1000 C in a helium stream and evolved gases continuously analyzed by a mass spectrometer. A continued focus of AMASE-2009 was analysis of carbonates from the Spitsbergen Sverrefjell volcano [1]. The similarity of macromolecular carbon (MMC) associated with magnetite in carbonate globules found in an ice cave in Sverrefjell to those studied in the Mars meteorite ALH84001 has been a motivation for their intensive study. The MMC associated with these carbonates appears to have been formed abiotically [2] following the eruption of the Sverrefjell volcano into glacial ice. The AMASE-2008 EGA studies of microsampled carbonate layers are described and the ability and limitations of these in situ tools to distinguish biomarkers. [1] H. Amundsen, Nature 327, 692-695 (1987). [2] A. Steele et al., Meteoritics and Planetary Science 42, 1549-1566 (2007) Acknowledgement: Support of this work is from the NASA ASTEP program with A. Steele AMASE PI and H. Amundsen Expedition lead.

  1. An Evolved Orthogonal Enzyme/Cofactor Pair.

    PubMed

    Reynolds, Evan W; McHenry, Matthew W; Cannac, Fabien; Gober, Joshua G; Snow, Christopher D; Brustad, Eric M

    2016-09-28

    We introduce a strategy that expands the functionality of hemoproteins through orthogonal enzyme/heme pairs. By exploiting the ability of a natural heme transport protein, ChuA, to promiscuously import heme derivatives, we have evolved a cytochrome P450 (P450BM3) that selectively incorporates a nonproteinogenic cofactor, iron deuteroporphyrin IX (Fe-DPIX), even in the presence of endogenous heme. Crystal structures show that selectivity gains are due to mutations that introduce steric clash with the heme vinyl groups while providing a complementary binding surface for the smaller Fe-DPIX cofactor. Furthermore, the evolved orthogonal enzyme/cofactor pair is active in non-natural carbenoid-mediated olefin cyclopropanation. This methodology for the generation of orthogonal enzyme/cofactor pairs promises to expand cofactor diversity in artificial metalloenzymes.

  2. Evolving neural networks through augmenting topologies.

    PubMed

    Stanley, Kenneth O; Miikkulainen, Risto

    2002-01-01

    An important question in neuroevolution is how to gain an advantage from evolving neural network topologies along with weights. We present a method, NeuroEvolution of Augmenting Topologies (NEAT), which outperforms the best fixed-topology method on a challenging benchmark reinforcement learning task. We claim that the increased efficiency is due to (1) employing a principled method of crossover of different topologies, (2) protecting structural innovation using speciation, and (3) incrementally growing from minimal structure. We test this claim through a series of ablation studies that demonstrate that each component is necessary to the system as a whole and to each other. What results is significantly faster learning. NEAT is also an important contribution to GAs because it shows how it is possible for evolution to both optimize and complexify solutions simultaneously, offering the possibility of evolving increasingly complex solutions over generations, and strengthening the analogy with biological evolution. PMID:12180173

  3. Evolving neural models of path integration.

    PubMed

    Vickerstaff, R J; Di Paolo, E A

    2005-09-01

    We use a genetic algorithm to evolve neural models of path integration, with particular emphasis on reproducing the homing behaviour of Cataglyphis fortis ants. This is done within the context of a complete model system, including an explicit representation of the animal's movements within its environment. We show that it is possible to produce a neural network without imposing a priori any particular system for the internal representation of the animal's home vector. The best evolved network obtained is analysed in detail and is found to resemble the bicomponent model of Mittelstaedt. Because of the presence of leaky integration, the model can reproduce the systematic navigation errors found in desert ants. The model also naturally mimics the searching behaviour that ants perform once they have reached their estimate of the nest location. The results support possible roles for leaky integration and cosine-shaped compass response functions in path integration.

  4. Evolved gas analysis of secondary organic aerosols

    SciTech Connect

    Grosjean, D.; Williams, E.L. II; Grosjean, E. ); Novakov, T. )

    1994-11-01

    Secondary organic aerosols have been characterized by evolved gas analysis (EGA). Hydrocarbons selected as aerosol precursors were representative of anthropogenic emissions (cyclohexene, cyclopentene, 1-decene and 1-dodecene, n-dodecane, o-xylene, and 1,3,5-trimethylbenzene) and of biogenic emissions (the terpenes [alpha]-pinene, [beta]-pinene and d-limonene and the sesquiterpene trans-caryophyllene). Also analyzed by EGA were samples of secondary, primary (highway tunnel), and ambient (urban) aerosols before and after exposure to ozone and other photochemical oxidants. The major features of the EGA thermograms (amount of CO[sub 2] evolved as a function of temperature) are described. The usefulness and limitations of EGA data for source apportionment of atmospheric particulate carbon are briefly discussed. 28 refs., 7 figs., 4 tabs.

  5. The evolving definition of systemic arterial hypertension.

    PubMed

    Ram, C Venkata S; Giles, Thomas D

    2010-05-01

    Systemic hypertension is an important risk factor for premature cardiovascular disease. Hypertension also contributes to excessive morbidity and mortality. Whereas excellent therapeutic options are available to treat hypertension, there is an unsettled issue about the very definition of hypertension. At what level of blood pressure should we treat hypertension? Does the definition of hypertension change in the presence of co-morbid conditions? This article covers in detail the evolving concepts in the diagnosis and management of hypertension.

  6. Quantum games on evolving random networks

    NASA Astrophysics Data System (ADS)

    Pawela, Łukasz

    2016-09-01

    We study the advantages of quantum strategies in evolutionary social dilemmas on evolving random networks. We focus our study on the two-player games: prisoner's dilemma, snowdrift and stag-hunt games. The obtained result show the benefits of quantum strategies for the prisoner's dilemma game. For the other two games, we obtain regions of parameters where the quantum strategies dominate, as well as regions where the classical strategies coexist.

  7. Continuous evaluation of evolving behavioral intervention technologies.

    PubMed

    Mohr, David C; Cheung, Ken; Schueller, Stephen M; Hendricks Brown, C; Duan, Naihua

    2013-10-01

    Behavioral intervention technologies (BITs) are web-based and mobile interventions intended to support patients and consumers in changing behaviors related to health, mental health, and well-being. BITs are provided to patients and consumers in clinical care settings and commercial marketplaces, frequently with little or no evaluation. Current evaluation methods, including RCTs and implementation studies, can require years to validate an intervention. This timeline is fundamentally incompatible with the BIT environment, where technology advancement and changes in consumer expectations occur quickly, necessitating rapidly evolving interventions. However, BITs can routinely and iteratively collect data in a planned and strategic manner and generate evidence through systematic prospective analyses, thereby creating a system that can "learn." A methodologic framework, Continuous Evaluation of Evolving Behavioral Intervention Technologies (CEEBIT), is proposed that can support the evaluation of multiple BITs or evolving versions, eliminating those that demonstrate poorer outcomes, while allowing new BITs to be entered at any time. CEEBIT could be used to ensure the effectiveness of BITs provided through deployment platforms in clinical care organizations or BIT marketplaces. The features of CEEBIT are described, including criteria for the determination of inferiority, determination of BIT inclusion, methods of assigning consumers to BITs, definition of outcomes, and evaluation of the usefulness of the system. CEEBIT offers the potential to collapse initial evaluation and postmarketing surveillance, providing ongoing assurance of safety and efficacy to patients and consumers, payers, and policymakers. PMID:24050429

  8. Transistor Level Circuit Experiments using Evolvable Hardware

    NASA Technical Reports Server (NTRS)

    Stoica, A.; Zebulum, R. S.; Keymeulen, D.; Ferguson, M. I.; Daud, Taher; Thakoor, A.

    2005-01-01

    The Jet Propulsion Laboratory (JPL) performs research in fault tolerant, long life, and space survivable electronics for the National Aeronautics and Space Administration (NASA). With that focus, JPL has been involved in Evolvable Hardware (EHW) technology research for the past several years. We have advanced the technology not only by simulation and evolution experiments, but also by designing, fabricating, and evolving a variety of transistor-based analog and digital circuits at the chip level. EHW refers to self-configuration of electronic hardware by evolutionary/genetic search mechanisms, thereby maintaining existing functionality in the presence of degradations due to aging, temperature, and radiation. In addition, EHW has the capability to reconfigure itself for new functionality when required for mission changes or encountered opportunities. Evolution experiments are performed using a genetic algorithm running on a DSP as the reconfiguration mechanism and controlling the evolvable hardware mounted on a self-contained circuit board. Rapid reconfiguration allows convergence to circuit solutions in the order of seconds. The paper illustrates hardware evolution results of electronic circuits and their ability to perform under 230 C temperature as well as radiations of up to 250 kRad.

  9. Continuous Evaluation of Evolving Behavioral Intervention Technologies

    PubMed Central

    Mohr, David C.; Cheung, Ken; Schueller, Stephen M.; Brown, C. Hendricks; Duan, Naihua

    2013-01-01

    Behavioral intervention technologies (BITs) are web-based and mobile interventions intended to support patients and consumers in changing behaviors related to health, mental health, and well-being. BITs are provided to patients and consumers in clinical care settings and commercial marketplaces, frequently with little or no evaluation. Current evaluation methods, including RCTs and implementation studies, can require years to validate an intervention. This timeline is fundamentally incompatible with the BIT environment, where technology advancement and changes in consumer expectations occur quickly, necessitating rapidly evolving interventions. However, BITs can routinely and iteratively collect data in a planned and strategic manner and generate evidence through systematic prospective analyses, thereby creating a system that can “learn.” A methodologic framework, Continuous Evaluation of Evolving Behavioral Intervention Technologies (CEEBIT), is proposed that can support the evaluation of multiple BITs or evolving versions, eliminating those that demonstrate poorer outcomes, while allowing new BITs to be entered at any time. CEEBIT could be used to ensure the effectiveness of BITs provided through deployment platforms in clinical care organizations or BIT marketplaces. The features of CEEBIT are described, including criteria for the determination of inferiority, determination of BIT inclusion, methods of assigning consumers to BITs, definition of outcomes, and evaluation of the usefulness of the system. CEEBIT offers the potential to collapse initial evaluation and postmarketing surveillance, providing ongoing assurance of safety and efficacy to patients and consumers, payers, and policymakers. PMID:24050429

  10. Evolving specialization of the arthropod nervous system

    PubMed Central

    Jarvis, Erin; Bruce, Heather S.; Patel, Nipam H.

    2012-01-01

    The diverse array of body plans possessed by arthropods is created by generating variations upon a design of repeated segments formed during development, using a relatively small “toolbox” of conserved patterning genes. These attributes make the arthropod body plan a valuable model for elucidating how changes in development create diversity of form. As increasingly specialized segments and appendages evolved in arthropods, the nervous systems of these animals also evolved to control the function of these structures. Although there is a remarkable degree of conservation in neural development both between individual segments in any given species and between the nervous systems of different arthropod groups, the differences that do exist are informative for inferring general principles about the holistic evolution of body plans. This review describes developmental processes controlling neural segmentation and regionalization, highlighting segmentation mechanisms that create both ectodermal and neural segments, as well as recent studies of the role of Hox genes in generating regional specification within the central nervous system. We argue that this system generates a modular design that allows the nervous system to evolve in concert with the body segments and their associated appendages. This information will be useful in future studies of macroevolutionary changes in arthropod body plans, especially in understanding how these transformations can be made in a way that retains the function of appendages during evolutionary transitions in morphology. PMID:22723369

  11. Electron acceleration and radiation in evolving complex active regions

    NASA Astrophysics Data System (ADS)

    Anastasiadis, A.; Gontikakis, C.; Vilmer, N.; Vlahos, L.

    2004-07-01

    We present a model for the acceleration and radiation of solar energetic particles (electrons) in evolving complex active regions. The spatio - temporal evolution of active regions is calculated using a cellular automaton model, based on self-organized criticality. The acceleration of electrons is due to the presence of randomly placed, localized electric fields produced by the energy release process, simulated by the cellular automaton model. We calculate the resulting kinetic energy distributions of the particles and their emitted X-ray radiation spectra using the thick target approximation, and we perform a parametric study with respect to number of electric fields present and thermal temperature of the injected distribution. Finally, comparing our results with the existing observations, we find that they are in a good agreement with the observed X-ray spectra in the energy range 100-1000 keV.

  12. Water Maser Emission Around Low/Intermediate Mass Evolved Stars

    NASA Astrophysics Data System (ADS)

    Leal-Ferreira, M. L.; Vlemmings, W. H. T.; Diamond, P. J.; Kemball, A.; Amiri, N.; Desmurs, J.-F.

    2012-07-01

    We present results of Very Long Baseline Array (VLBA) polarimetric 22 GHz H2O maser observations of a number of low/intermediate mass evolved stars. We observed 3 Miras (Ap Lyn, IK Tau and IRC+60370), 1 semi-regular variable (RT Vir) and 1 pPN (OH231.8+4.2). Circular polarization is detected in the H2O maser region of OH231.8+4.2 and we infer a magnetic field of |B||| = ~45 mG. This implies an extrapolated magnetic field of ~2.5 G on the surface of the central star. The preliminary results on RT Vir and IRC+60370 also indicate the first detection of weak H2O maser linear polarization.

  13. Evolvability Is an Evolved Ability: The Coding Concept as the Arch-Unit of Natural Selection.

    PubMed

    Janković, Srdja; Ćirković, Milan M

    2016-03-01

    Physical processes that characterize living matter are qualitatively distinct in that they involve encoding and transfer of specific types of information. Such information plays an active part in the control of events that are ultimately linked to the capacity of the system to persist and multiply. This algorithmicity of life is a key prerequisite for its Darwinian evolution, driven by natural selection acting upon stochastically arising variations of the encoded information. The concept of evolvability attempts to define the total capacity of a system to evolve new encoded traits under appropriate conditions, i.e., the accessible section of total morphological space. Since this is dependent on previously evolved regulatory networks that govern information flow in the system, evolvability itself may be regarded as an evolved ability. The way information is physically written, read and modified in living cells (the "coding concept") has not changed substantially during the whole history of the Earth's biosphere. This biosphere, be it alone or one of many, is, accordingly, itself a product of natural selection, since the overall evolvability conferred by its coding concept (nucleic acids as information carriers with the "rulebook of meanings" provided by codons, as well as all the subsystems that regulate various conditional information-reading modes) certainly played a key role in enabling this biosphere to survive up to the present, through alterations of planetary conditions, including at least five catastrophic events linked to major mass extinctions. We submit that, whatever the actual prebiotic physical and chemical processes may have been on our home planet, or may, in principle, occur at some time and place in the Universe, a particular coding concept, with its respective potential to give rise to a biosphere, or class of biospheres, of a certain evolvability, may itself be regarded as a unit (indeed the arch-unit) of natural selection.

  14. Evolvability Is an Evolved Ability: The Coding Concept as the Arch-Unit of Natural Selection

    NASA Astrophysics Data System (ADS)

    Janković, Srdja; Ćirković, Milan M.

    2016-03-01

    Physical processes that characterize living matter are qualitatively distinct in that they involve encoding and transfer of specific types of information. Such information plays an active part in the control of events that are ultimately linked to the capacity of the system to persist and multiply. This algorithmicity of life is a key prerequisite for its Darwinian evolution, driven by natural selection acting upon stochastically arising variations of the encoded information. The concept of evolvability attempts to define the total capacity of a system to evolve new encoded traits under appropriate conditions, i.e., the accessible section of total morphological space. Since this is dependent on previously evolved regulatory networks that govern information flow in the system, evolvability itself may be regarded as an evolved ability. The way information is physically written, read and modified in living cells (the "coding concept") has not changed substantially during the whole history of the Earth's biosphere. This biosphere, be it alone or one of many, is, accordingly, itself a product of natural selection, since the overall evolvability conferred by its coding concept (nucleic acids as information carriers with the "rulebook of meanings" provided by codons, as well as all the subsystems that regulate various conditional information-reading modes) certainly played a key role in enabling this biosphere to survive up to the present, through alterations of planetary conditions, including at least five catastrophic events linked to major mass extinctions. We submit that, whatever the actual prebiotic physical and chemical processes may have been on our home planet, or may, in principle, occur at some time and place in the Universe, a particular coding concept, with its respective potential to give rise to a biosphere, or class of biospheres, of a certain evolvability, may itself be regarded as a unit (indeed the arch-unit) of natural selection.

  15. Survivability Is More Fundamental Than Evolvability

    PubMed Central

    Palmer, Michael E.; Feldman, Marcus W.

    2012-01-01

    For a lineage to survive over long time periods, it must sometimes change. This has given rise to the term evolvability, meaning the tendency to produce adaptive variation. One lineage may be superior to another in terms of its current standing variation, or it may tend to produce more adaptive variation. However, evolutionary outcomes depend on more than standing variation and produced adaptive variation: deleterious variation also matters. Evolvability, as most commonly interpreted, is not predictive of evolutionary outcomes. Here, we define a predictive measure of the evolutionary success of a lineage that we call the k-survivability, defined as the probability that the lineage avoids extinction for k generations. We estimate the k-survivability using multiple experimental replicates. Because we measure evolutionary outcomes, the initial standing variation, the full spectrum of generated variation, and the heritability of that variation are all incorporated. Survivability also accounts for the decreased joint likelihood of extinction of sub-lineages when they 1) disperse in space, or 2) diversify in lifestyle. We illustrate measurement of survivability with in silico models, and suggest that it may also be measured in vivo using multiple longitudinal replicates. The k-survivability is a metric that enables the quantitative study of, for example, the evolution of 1) mutation rates, 2) dispersal mechanisms, 3) the genotype-phenotype map, and 4) sexual reproduction, in temporally and spatially fluctuating environments. Although these disparate phenomena evolve by well-understood microevolutionary rules, they are also subject to the macroevolutionary constraint of long-term survivability. PMID:22723844

  16. Evolvable circuit with transistor-level reconfigurability

    NASA Technical Reports Server (NTRS)

    Stoica, Adrian (Inventor); Salazar-Lazaro, Carlos Harold (Inventor)

    2004-01-01

    An evolvable circuit includes a plurality of reconfigurable switches, a plurality of transistors within a region of the circuit, the plurality of transistors having terminals, the plurality of transistors being coupled between a power source terminal and a power sink terminal so as to be capable of admitting power between the power source terminal and the power sink terminal, the plurality of transistors being coupled so that every transistor terminal to transistor terminal coupling within the region of the circuit comprises a reconfigurable switch.

  17. Present weather and climate: evolving conditions

    USGS Publications Warehouse

    Hoerling, Martin P; Dettinger, Michael; Wolter, Klaus; Lukas, Jeff; Eischeid, Jon K.; Nemani, Rama; Liebmann, Brant; Kunkel, Kenneth E.

    2013-01-01

    This chapter assesses weather and climate variability and trends in the Southwest, using observed climate and paleoclimate records. It analyzes the last 100 years of climate variability in comparison to the last 1,000 years, and links the important features of evolving climate conditions to river flow variability in four of the region’s major drainage basins. The chapter closes with an assessment of the monitoring and scientific research needed to increase confidence in understanding when climate episodes, events, and phenomena are attributable to human-caused climate change.

  18. The Evolving Theory of Evolutionary Radiations.

    PubMed

    Simões, M; Breitkreuz, L; Alvarado, M; Baca, S; Cooper, J C; Heins, L; Herzog, K; Lieberman, B S

    2016-01-01

    Evolutionary radiations have intrigued biologists for more than 100 years, and our understanding of the patterns and processes associated with these radiations continues to grow and evolve. Recently it has been recognized that there are many different types of evolutionary radiation beyond the well-studied adaptive radiations. We focus here on multifarious types of evolutionary radiations, paying special attention to the abiotic factors that might trigger diversification in clades. We integrate concepts such as exaptation, species selection, coevolution, and the turnover-pulse hypothesis (TPH) into the theoretical framework of evolutionary radiations. We also discuss other phenomena that are related to, but distinct from, evolutionary radiations that have relevance for evolutionary biology.

  19. Evolving Black Holes with Wavy Initial Data

    NASA Astrophysics Data System (ADS)

    Kelly, Bernard; Tichy, Wolfgang; Zlochower, Yosef; Campanelli, Manuela; Whiting, Bernard

    2009-05-01

    In Kelly et al. [Phys. Rev. D v. 76, 024008 (2007)], we presented new binary black-hole initial data adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to 2.5 post-Newtonian order, and contains a transverse-traceless ``wavy'' metric contribution, violating the standard assumption of conformal flatness. We report on progress in evolving this data with a modern moving-puncture implementation of the BSSN equations in several numerical codes. We will discuss the effect of the new metric terms on junk radiation and continuity of physical radiation extracted.

  20. Mobile computing acceptance grows as applications evolve.

    PubMed

    Porn, Louis M; Patrick, Kelly

    2002-01-01

    Handheld devices are becoming more cost-effective to own, and their use in healthcare environments is increasing. Handheld devices currently are being used for e-prescribing, charge capture, and accessing daily schedules and reference tools. Future applications may include education on medications, dictation, order entry, and test-results reporting. Selecting the right handheld device requires careful analysis of current and future applications, as well as vendor expertise. It is important to recognize the technology will continue to evolve over the next three years. PMID:11806321

  1. Mobile computing acceptance grows as applications evolve.

    PubMed

    Porn, Louis M; Patrick, Kelly

    2002-01-01

    Handheld devices are becoming more cost-effective to own, and their use in healthcare environments is increasing. Handheld devices currently are being used for e-prescribing, charge capture, and accessing daily schedules and reference tools. Future applications may include education on medications, dictation, order entry, and test-results reporting. Selecting the right handheld device requires careful analysis of current and future applications, as well as vendor expertise. It is important to recognize the technology will continue to evolve over the next three years.

  2. Earth As an Evolving Planetary System

    NASA Astrophysics Data System (ADS)

    Meert, Joseph G.

    2005-05-01

    ``System'' is an overused buzzword in textbooks covering geological sciences. Describing the Earth as a system of component parts is a reasonable concept, but providing a comprehensive framework for detailing the system is a more formidable task. Kent Condie lays out the systems approach in an easy-to-read introductory chapter in Earth as an Evolving Planetary System. In the book, Condie makes a valiant attempt at taking the mélange of diverse subjects in the solid Earth sciences and weaving them into a coherent tapestry.

  3. Single neutron star systems evolving with fallback discs

    NASA Astrophysics Data System (ADS)

    Ertan, Unal; Caliskan, Sirin; Alpar, Mehmet Ali; Benli, Onur; Trümper, Joachim E.

    2016-07-01

    We have investigated the long-term evolution of the young neutron star systems, namely anomalous X-ray pulsars (AXPs), soft gamma repeaters (SGRs), dim isolated neutron stars (XDINs), and the so-called "high-B radio pulsars" in the frame of the fallback disk disc model. We have shown that the X-ray luminosities and the rotational properties of individual sources in these different populations can be achieved by neutron stars evolving with fallback disks and with conventional dipole magnetic fields of young neutron stars. Presence of small-scale magnetar fields in the higher multi-poles which are likely to be responsible for soft gamma bursts observed from these systems is compatible with the fallback disk model, since the rotational evolution of the star is governed by the interaction between the large-scale dipole field and the disc. The results of our model is self-consistent in that (1) the X-ray luminosity, period and period derivative of individual sources are produced simultaneously, and (2) these results are obtained with very similar set of main disk parameters for all these systems with rather different properties. Our results indicate that all known AXPs, except two sources, are in the accretion phase at present. The 6 XDINs with confirmed period and period derivatives reached their long periods in the accretion epochs in the past. At present, XDINs are evolving in the propeller phase without accretion, but they are still slowing down under effect of the disk torques. For the "high-B radio pulsars", the source properties are obtained in the phases when accretion is not allowed, which is consistent with the radio pulsar property of these sources.

  4. Have plants evolved to self-immolate?

    PubMed

    Bowman, David M J S; French, Ben J; Prior, Lynda D

    2014-01-01

    By definition fire prone ecosystems have highly combustible plants, leading to the hypothesis, first formally stated by Mutch in 1970, that community flammability is the product of natural selection of flammable traits. However, proving the "Mutch hypothesis" has presented an enormous challenge for fire ecologists given the difficulty in establishing cause and effect between landscape fire and flammable plant traits. Individual plant traits (such as leaf moisture content, retention of dead branches and foliage, oil rich foliage) are known to affect the flammability of plants but there is no evidence these characters evolved specifically to self-immolate, although some of these traits may have been secondarily modified to increase the propensity to burn. Demonstrating individual benefits from self-immolation is extraordinarily difficult, given the intersection of the physical environmental factors that control landscape fire (fuel production, dryness and ignitions) with community flammability properties that emerge from numerous traits of multiple species (canopy cover and litter bed bulk density). It is more parsimonious to conclude plants have evolved mechanisms to tolerate, but not promote, landscape fire. PMID:25414710

  5. Evolving resistance to obesity in an insect.

    PubMed

    Warbrick-Smith, James; Behmer, Spencer T; Lee, Kwang Pum; Raubenheimer, David; Simpson, Stephen J

    2006-09-19

    Failure to adapt to a changing nutritional environment comes at a cost, as evidenced by the modern human obesity crisis. Consumption of energy-rich diets can lead to obesity and is associated with deleterious consequences not only in humans but also in many other animals, including insects. The question thus arises whether animals restricted over multiple generations to high-energy diets can evolve mechanisms to limit the deposition of adverse levels of body fat. We show that Plutella xylostella caterpillars reared for multiple generations on carbohydrate-rich foods (either a chemically defined artificial diet or a high-starch Arabidopsis mutant) progressively developed the ability to eat excess carbohydrate without laying it down as fat, providing strong evidence that excess fat storage has a fitness cost. In contrast, caterpillars reared in carbohydrate-scarce environments (a chemically defined artificial diet or a low-starch Arabidopsis mutant) had a greater propensity to store ingested carbohydrate as fat. Additionally, insects reared on the low-starch Arabidopsis mutant evolved a preference for laying their eggs on this plant, whereas those selected on the high-starch Arabidopsis mutant showed no preference. Our results provide an experimental example of metabolic adaptation in the face of changes in the nutritional environment and suggest that changes in plant macronutrient profiles may promote host-associated population divergence.

  6. Collapse of cooperation in evolving games

    PubMed Central

    Stewart, Alexander J.; Plotkin, Joshua B.

    2014-01-01

    Game theory provides a quantitative framework for analyzing the behavior of rational agents. The Iterated Prisoner’s Dilemma in particular has become a standard model for studying cooperation and cheating, with cooperation often emerging as a robust outcome in evolving populations. Here we extend evolutionary game theory by allowing players’ payoffs as well as their strategies to evolve in response to selection on heritable mutations. In nature, many organisms engage in mutually beneficial interactions and individuals may seek to change the ratio of risk to reward for cooperation by altering the resources they commit to cooperative interactions. To study this, we construct a general framework for the coevolution of strategies and payoffs in arbitrary iterated games. We show that, when there is a tradeoff between the benefits and costs of cooperation, coevolution often leads to a dramatic loss of cooperation in the Iterated Prisoner’s Dilemma. The collapse of cooperation is so extreme that the average payoff in a population can decline even as the potential reward for mutual cooperation increases. Depending upon the form of tradeoffs, evolution may even move away from the Iterated Prisoner’s Dilemma game altogether. Our work offers a new perspective on the Prisoner’s Dilemma and its predictions for cooperation in natural populations; and it provides a general framework to understand the coevolution of strategies and payoffs in iterated interactions. PMID:25422421

  7. Caterpillars evolved from onychophorans by hybridogenesis.

    PubMed

    Williamson, Donald I

    2009-11-24

    I reject the Darwinian assumption that larvae and their adults evolved from a single common ancestor. Rather I posit that, in animals that metamorphose, the basic types of larvae originated as adults of different lineages, i.e., larvae were transferred when, through hybridization, their genomes were acquired by distantly related animals. "Caterpillars," the name for eruciforms with thoracic and abdominal legs, are larvae of lepidopterans, hymenopterans, and mecopterans (scorpionflies). Grubs and maggots, including the larvae of beetles, bees, and flies, evolved from caterpillars by loss of legs. Caterpillar larval organs are dismantled and reconstructed in the pupal phase. Such indirect developmental patterns (metamorphoses) did not originate solely by accumulation of random mutations followed by natural selection; rather they are fully consistent with my concept of evolution by hybridogenesis. Members of the phylum Onychophora (velvet worms) are proposed as the evolutionary source of caterpillars and their grub or maggot descendants. I present a molecular biological research proposal to test my thesis. By my hypothesis 2 recognizable sets of genes are detectable in the genomes of all insects with caterpillar grub- or maggot-like larvae: (i) onychophoran genes that code for proteins determining larval morphology/physiology and (ii) sequentially expressed insect genes that code for adult proteins. The genomes of insects and other animals that, by contrast, entirely lack larvae comprise recognizable sets of genes from single animal common ancestors.

  8. Collapse of cooperation in evolving games.

    PubMed

    Stewart, Alexander J; Plotkin, Joshua B

    2014-12-01

    Game theory provides a quantitative framework for analyzing the behavior of rational agents. The Iterated Prisoner's Dilemma in particular has become a standard model for studying cooperation and cheating, with cooperation often emerging as a robust outcome in evolving populations. Here we extend evolutionary game theory by allowing players' payoffs as well as their strategies to evolve in response to selection on heritable mutations. In nature, many organisms engage in mutually beneficial interactions and individuals may seek to change the ratio of risk to reward for cooperation by altering the resources they commit to cooperative interactions. To study this, we construct a general framework for the coevolution of strategies and payoffs in arbitrary iterated games. We show that, when there is a tradeoff between the benefits and costs of cooperation, coevolution often leads to a dramatic loss of cooperation in the Iterated Prisoner's Dilemma. The collapse of cooperation is so extreme that the average payoff in a population can decline even as the potential reward for mutual cooperation increases. Depending upon the form of tradeoffs, evolution may even move away from the Iterated Prisoner's Dilemma game altogether. Our work offers a new perspective on the Prisoner's Dilemma and its predictions for cooperation in natural populations; and it provides a general framework to understand the coevolution of strategies and payoffs in iterated interactions.

  9. Caterpillars evolved from onychophorans by hybridogenesis.

    PubMed

    Williamson, Donald I

    2009-11-24

    I reject the Darwinian assumption that larvae and their adults evolved from a single common ancestor. Rather I posit that, in animals that metamorphose, the basic types of larvae originated as adults of different lineages, i.e., larvae were transferred when, through hybridization, their genomes were acquired by distantly related animals. "Caterpillars," the name for eruciforms with thoracic and abdominal legs, are larvae of lepidopterans, hymenopterans, and mecopterans (scorpionflies). Grubs and maggots, including the larvae of beetles, bees, and flies, evolved from caterpillars by loss of legs. Caterpillar larval organs are dismantled and reconstructed in the pupal phase. Such indirect developmental patterns (metamorphoses) did not originate solely by accumulation of random mutations followed by natural selection; rather they are fully consistent with my concept of evolution by hybridogenesis. Members of the phylum Onychophora (velvet worms) are proposed as the evolutionary source of caterpillars and their grub or maggot descendants. I present a molecular biological research proposal to test my thesis. By my hypothesis 2 recognizable sets of genes are detectable in the genomes of all insects with caterpillar grub- or maggot-like larvae: (i) onychophoran genes that code for proteins determining larval morphology/physiology and (ii) sequentially expressed insect genes that code for adult proteins. The genomes of insects and other animals that, by contrast, entirely lack larvae comprise recognizable sets of genes from single animal common ancestors. PMID:19717430

  10. Evolving resistance to obesity in an insect

    PubMed Central

    Warbrick-Smith, James; Behmer, Spencer T.; Lee, Kwang Pum; Raubenheimer, David; Simpson, Stephen J.

    2006-01-01

    Failure to adapt to a changing nutritional environment comes at a cost, as evidenced by the modern human obesity crisis. Consumption of energy-rich diets can lead to obesity and is associated with deleterious consequences not only in humans but also in many other animals, including insects. The question thus arises whether animals restricted over multiple generations to high-energy diets can evolve mechanisms to limit the deposition of adverse levels of body fat. We show that Plutella xylostella caterpillars reared for multiple generations on carbohydrate-rich foods (either a chemically defined artificial diet or a high-starch Arabidopsis mutant) progressively developed the ability to eat excess carbohydrate without laying it down as fat, providing strong evidence that excess fat storage has a fitness cost. In contrast, caterpillars reared in carbohydrate-scarce environments (a chemically defined artificial diet or a low-starch Arabidopsis mutant) had a greater propensity to store ingested carbohydrate as fat. Additionally, insects reared on the low-starch Arabidopsis mutant evolved a preference for laying their eggs on this plant, whereas those selected on the high-starch Arabidopsis mutant showed no preference. Our results provide an experimental example of metabolic adaptation in the face of changes in the nutritional environment and suggest that changes in plant macronutrient profiles may promote host-associated population divergence. PMID:16968774

  11. Shaping the outflows of evolved stars

    NASA Astrophysics Data System (ADS)

    Mohamed, Shazrene

    2015-08-01

    Both hot and cool evolved stars, e.g., red (super)giants and Wolf-Rayet stars, lose copious amounts of mass, momentum and mechanical energy through powerful, dense stellar winds. The interaction of these outflows with their surroundings results in highly structured and complex circumstellar environments, often featuring knots, arcs, shells and spirals. Recent improvements in computational power and techniques have led to the development of detailed, multi-dimensional simulations that have given new insight into the origin of these structures, and better understanding of the physical mechanisms driving their formation. In this talk, I will discuss three of the main mechanisms that shape the outflows of evolved stars:- interaction with the interstellar medium (ISM), i.e., wind-ISM interactions- interaction with a stellar wind, either from a previous phase of evolution or the wind from a companion star, i.e., wind-wind interactions- and interaction with a companion star that has a weak or insignicant outflow (e.g., a compact companion such as a neutron star or black hole), i.e., wind-companion interactions.I will also highlight the broader implications and impact of these stellar wind interactions for other phenomena, e.g, for symbiotic and X-ray binaries, supernovae and Gamma-ray bursts.

  12. Early formation of evolved asteroidal crust.

    PubMed

    Day, James M D; Ash, Richard D; Liu, Yang; Bellucci, Jeremy J; Rumble, Douglas; McDonough, William F; Walker, Richard J; Taylor, Lawrence A

    2009-01-01

    Mechanisms for the formation of crust on planetary bodies remain poorly understood. It is generally accepted that Earth's andesitic continental crust is the product of plate tectonics, whereas the Moon acquired its feldspar-rich crust by way of plagioclase flotation in a magma ocean. Basaltic meteorites provide evidence that, like the terrestrial planets, some asteroids generated crust and underwent large-scale differentiation processes. Until now, however, no evolved felsic asteroidal crust has been sampled or observed. Here we report age and compositional data for the newly discovered, paired and differentiated meteorites Graves Nunatak (GRA) 06128 and GRA 06129. These meteorites are feldspar-rich, with andesite bulk compositions. Their age of 4.52 +/- 0.06 Gyr demonstrates formation early in Solar System history. The isotopic and elemental compositions, degree of metamorphic re-equilibration and sulphide-rich nature of the meteorites are most consistent with an origin as partial melts from a volatile-rich, oxidized asteroid. GRA 06128 and 06129 are the result of a newly recognized style of evolved crust formation, bearing witness to incomplete differentiation of their parent asteroid and to previously unrecognized diversity of early-formed materials in the Solar System. PMID:19129845

  13. Early formation of evolved asteroidal crust

    NASA Astrophysics Data System (ADS)

    Day, James M. D.; Ash, Richard D.; Liu, Yang; Bellucci, Jeremy J.; Rumble, Douglas, III; McDonough, William F.; Walker, Richard J.; Taylor, Lawrence A.

    2009-01-01

    Mechanisms for the formation of crust on planetary bodies remain poorly understood. It is generally accepted that Earth's andesitic continental crust is the product of plate tectonics, whereas the Moon acquired its feldspar-rich crust by way of plagioclase flotation in a magma ocean. Basaltic meteorites provide evidence that, like the terrestrial planets, some asteroids generated crust and underwent large-scale differentiation processes. Until now, however, no evolved felsic asteroidal crust has been sampled or observed. Here we report age and compositional data for the newly discovered, paired and differentiated meteorites Graves Nunatak (GRA) 06128 and GRA 06129. These meteorites are feldspar-rich, with andesite bulk compositions. Their age of 4.52+/-0.06Gyr demonstrates formation early in Solar System history. The isotopic and elemental compositions, degree of metamorphic re-equilibration and sulphide-rich nature of the meteorites are most consistent with an origin as partial melts from a volatile-rich, oxidized asteroid. GRA 06128 and 06129 are the result of a newly recognized style of evolved crust formation, bearing witness to incomplete differentiation of their parent asteroid and to previously unrecognized diversity of early-formed materials in the Solar System.

  14. Early formation of evolved asteroidal crust.

    PubMed

    Day, James M D; Ash, Richard D; Liu, Yang; Bellucci, Jeremy J; Rumble, Douglas; McDonough, William F; Walker, Richard J; Taylor, Lawrence A

    2009-01-01

    Mechanisms for the formation of crust on planetary bodies remain poorly understood. It is generally accepted that Earth's andesitic continental crust is the product of plate tectonics, whereas the Moon acquired its feldspar-rich crust by way of plagioclase flotation in a magma ocean. Basaltic meteorites provide evidence that, like the terrestrial planets, some asteroids generated crust and underwent large-scale differentiation processes. Until now, however, no evolved felsic asteroidal crust has been sampled or observed. Here we report age and compositional data for the newly discovered, paired and differentiated meteorites Graves Nunatak (GRA) 06128 and GRA 06129. These meteorites are feldspar-rich, with andesite bulk compositions. Their age of 4.52 +/- 0.06 Gyr demonstrates formation early in Solar System history. The isotopic and elemental compositions, degree of metamorphic re-equilibration and sulphide-rich nature of the meteorites are most consistent with an origin as partial melts from a volatile-rich, oxidized asteroid. GRA 06128 and 06129 are the result of a newly recognized style of evolved crust formation, bearing witness to incomplete differentiation of their parent asteroid and to previously unrecognized diversity of early-formed materials in the Solar System.

  15. Environmental stress and evolvability in microbial systems.

    PubMed

    Baquero, F

    2009-01-01

    The sustainability of life on the planet depends on the preservation of the existing microbial systems, which constitutes our major "biological atmosphere". The detection of variations in microbial systems as a result of anthropogenic or natural changes is critical both to detect and assess risks and to programme specific interventions. Changes in microbial systems provokes stress, probably altering the local evolutionary time by changing evolvability (the possibilities of microbes to evolve). Methods should be refined to properly assess diversity in microbial systems. We propose that such diversity estimations should be done on a multi-hierarchical scale, encompassing not only organisms, but sub-cellular entities (e.g. chromosomal domains, plasmids, transposons, integrons, genes, gene modules) and supra-cellular organizations (e.g. clones, populations, communities, ecosystems), applying Hamiltonian criteria of inclusive fitness for the different ensembles. In any of these entities, we can generally identify, in a fractal manner, constant and variable parts. Variation in these entities and ensembles is probably both reduced and increased by environmental stress. Because of that, variation in microbial systems might serve as mirrors or symptoms of the health of the planet. PMID:19220344

  16. The emotion system promotes diversity and evolvability

    PubMed Central

    Giske, Jarl; Eliassen, Sigrunn; Fiksen, Øyvind; Jakobsen, Per J.; Aksnes, Dag L.; Mangel, Marc; Jørgensen, Christian

    2014-01-01

    Studies on the relationship between the optimal phenotype and its environment have had limited focus on genotype-to-phenotype pathways and their evolutionary consequences. Here, we study how multi-layered trait architecture and its associated constraints prescribe diversity. Using an idealized model of the emotion system in fish, we find that trait architecture yields genetic and phenotypic diversity even in absence of frequency-dependent selection or environmental variation. That is, for a given environment, phenotype frequency distributions are predictable while gene pools are not. The conservation of phenotypic traits among these genetically different populations is due to the multi-layered trait architecture, in which one adaptation at a higher architectural level can be achieved by several different adaptations at a lower level. Our results emphasize the role of convergent evolution and the organismal level of selection. While trait architecture makes individuals more constrained than what has been assumed in optimization theory, the resulting populations are genetically more diverse and adaptable. The emotion system in animals may thus have evolved by natural selection because it simultaneously enhances three important functions, the behavioural robustness of individuals, the evolvability of gene pools and the rate of evolutionary innovation at several architectural levels. PMID:25100697

  17. Evolvability of an Optimal Recombination Rate.

    PubMed

    Lobkovsky, Alexander E; Wolf, Yuri I; Koonin, Eugene V

    2015-12-10

    Evolution and maintenance of genetic recombination and its relation to the mutational process is a long-standing, fundamental problem in evolutionary biology that is linked to the general problem of evolution of evolvability. We explored a stochastic model of the evolution of recombination using additive fitness and infinite allele assumptions but no assumptions on the sign or magnitude of the epistasis and the distribution of mutation effects. In this model, fluctuating negative epistasis and predominantly deleterious mutations arise naturally as a consequence of the additive fitness and a reservoir from which new alleles arrive with a fixed distribution of fitness effects. Analysis of the model revealed a nonmonotonic effect of recombination intensity on fitness, with an optimal recombination rate value which maximized fitness in steady state. The optimal recombination rate depended on the mutation rate and was evolvable, that is, subject to selection. The predictions of the model were compatible with the observations on the dependence between genome rearrangement rate and gene flux in microbial genomes.

  18. Collapse of cooperation in evolving games.

    PubMed

    Stewart, Alexander J; Plotkin, Joshua B

    2014-12-01

    Game theory provides a quantitative framework for analyzing the behavior of rational agents. The Iterated Prisoner's Dilemma in particular has become a standard model for studying cooperation and cheating, with cooperation often emerging as a robust outcome in evolving populations. Here we extend evolutionary game theory by allowing players' payoffs as well as their strategies to evolve in response to selection on heritable mutations. In nature, many organisms engage in mutually beneficial interactions and individuals may seek to change the ratio of risk to reward for cooperation by altering the resources they commit to cooperative interactions. To study this, we construct a general framework for the coevolution of strategies and payoffs in arbitrary iterated games. We show that, when there is a tradeoff between the benefits and costs of cooperation, coevolution often leads to a dramatic loss of cooperation in the Iterated Prisoner's Dilemma. The collapse of cooperation is so extreme that the average payoff in a population can decline even as the potential reward for mutual cooperation increases. Depending upon the form of tradeoffs, evolution may even move away from the Iterated Prisoner's Dilemma game altogether. Our work offers a new perspective on the Prisoner's Dilemma and its predictions for cooperation in natural populations; and it provides a general framework to understand the coevolution of strategies and payoffs in iterated interactions. PMID:25422421

  19. Have plants evolved to self-immolate?

    PubMed Central

    Bowman, David M. J. S.; French, Ben J.; Prior, Lynda D.

    2014-01-01

    By definition fire prone ecosystems have highly combustible plants, leading to the hypothesis, first formally stated by Mutch in 1970, that community flammability is the product of natural selection of flammable traits. However, proving the “Mutch hypothesis” has presented an enormous challenge for fire ecologists given the difficulty in establishing cause and effect between landscape fire and flammable plant traits. Individual plant traits (such as leaf moisture content, retention of dead branches and foliage, oil rich foliage) are known to affect the flammability of plants but there is no evidence these characters evolved specifically to self-immolate, although some of these traits may have been secondarily modified to increase the propensity to burn. Demonstrating individual benefits from self-immolation is extraordinarily difficult, given the intersection of the physical environmental factors that control landscape fire (fuel production, dryness and ignitions) with community flammability properties that emerge from numerous traits of multiple species (canopy cover and litter bed bulk density). It is more parsimonious to conclude plants have evolved mechanisms to tolerate, but not promote, landscape fire. PMID:25414710

  20. Evolving MEMS Resonator Designs for Fabrication

    NASA Technical Reports Server (NTRS)

    Hornby, Gregory S.; Kraus, William F.; Lohn, Jason D.

    2008-01-01

    Because of their small size and high reliability, microelectromechanical (MEMS) devices have the potential to revolution many areas of engineering. As with conventionally-sized engineering design, there is likely to be a demand for the automated design of MEMS devices. This paper describes our current status as we progress toward our ultimate goal of using an evolutionary algorithm and a generative representation to produce designs of a MEMS device and successfully demonstrate its transfer to an actual chip. To produce designs that are likely to transfer to reality, we present two ways to modify evaluation of designs. The first is to add location noise, differences between the actual dimensions of the design and the design blueprint, which is a technique we have used for our work in evolving antennas and robots. The second method is to add prestress to model the warping that occurs during the extreme heat of fabrication. In future we expect to fabricate and test some MEMS resonators that are evolved in this way.

  1. Platform for evolving genetic automata for text segmentation

    NASA Astrophysics Data System (ADS)

    Garris, Michael D.

    1992-07-01

    Developers of large-scale document processing and image recognition systems are in need of a dynamically robust character segmentation component. Without this essential module, potential turn-key products will remain in the laboratory indefinitely. An experiment of evolving a biologically based neural image processing system which has the ability to isolate characters within an unstructured text image is presented. In this study, organisms are simulated using a genetic algorithm with the goal of learning the intelligent behavior required for locating and consuming text image characters. Each artificial life-form is defined by a genotype containing a list of interdependent control parameters which contribute to specific functions of the organism. Control functions include vision, consumption, and movement. Using asexual reproduction in conjunction with random mutation, a domain independent solution for text segmentation is sought. For this experiment, an organism's vision system utilizes a rectangular receptor field with signals accumulated using Gabor functions. The optimal subset of Gabor kernel functions for conducting character segmentation are determined through the process of evolution. From the results, two analyses are presented. A study of performance over evolved generations shows that qualifiers for the natural selection of dominant organisms increased 62%. The second analysis visually compares and discusses the variations of dominant genotypes form the first generation to the uniform genotypes resulting from the final generation.

  2. Evolving Photospheric Flux Concentrations and Filament Dynamic Changes

    NASA Astrophysics Data System (ADS)

    Schmieder, B.; Aulanier, G.; Mein, P.; López Ariste, A.

    2006-11-01

    We analyze the role of weak photospheric flux concentrations that evolve in a filament channel, in the triggering of dynamic changes in the shape of a filament. The high polarimetric sensitivity of THEMIS allowed us to detect weak flux concentrations (few Gauss) associated with the filament development. The synoptic instruments (MDI, SOLIS) even if their sensitivity is much less than THEMIS were useful to follow any subsequent strengthening of these flux concentrations after their identification in the THEMIS magnetograms. We found that (1) the northern part of the filament develops an Hα barb at the same time that weak minority polarity elements develop near a plage; (2) a section in the southern part of the Hα filament gradually disappears and later reforms at the same time that several mixed-polarity magnetic elements appear, then subsequently cancel or spread away from each other. These changes correspond to increases in EUV emission, as observed by TRACE, EIT, and CDS. This suggests that the plasma is temporarily heated along the filament spine. An idealized sequence of force-free models of this filament channel, based on plasma-supporting magnetic dips occurring in the windings of a very weakly twisted flux tube, naturally explains the evolution of its southern part as being due to changes in the topology of the coronal magnetic field as the photospheric flux concentrations evolve.

  3. The evolving block universe and the meshing together of times.

    PubMed

    Ellis, George F R

    2014-10-01

    It has been proposed that spacetime should be regarded as an evolving block universe, bounded to the future by the present time, which continually extends to the future. This future boundary is defined at each time by measuring proper time along Ricci eigenlines from the start of the universe. A key point, then, is that physical reality can be represented at many different scales: hence, the passage of time may be seen as different at different scales, with quantum gravity determining the evolution of spacetime itself at the Planck scale, but quantum field theory and classical physics determining the evolution of events within spacetime at larger scales. The fundamental issue then arises as to how the effective times at different scales mesh together, leading to the concepts of global and local times.

  4. Microsatellites evolve more rapidly in humans than in chimpanzees

    SciTech Connect

    Rubinsztein, D.C.; Leggo, J.; Amos, W.

    1995-12-10

    Microsatellites are highly polymorphic markers consisting of varying numbers of tandem repeats. At different loci, these repeats can consist of one to five nucleotides. Microsatellites have been used in many fields of genetics, including genetic mapping, linkage disequilibrium analyses, forensic studies, and population genetics. It is important that we understand their mutational processes better so that they can be exploited optimally for studies of human diversity and evolutionary genetics. We have analyzed 24 microsatellite loci in chimpanzees, East Anglians, and Sub-Saharan Africans. The stepwise-weighted genetic distances between the humans and the chimpanzees and between the two human populations were calculated according to the method described by Deka et al. The ratio of the genetic distances between the chimpanzees and the humans relative to that between the Africans and the East Anglians was more than 10 times smaller than expected. This suggests that microsatellites have evolved more rapidly in humans than in chimpanzees. 12 refs., 1 tab.

  5. Evolving spiking networks with variable resistive memories.

    PubMed

    Howard, Gerard; Bull, Larry; de Lacy Costello, Ben; Gale, Ella; Adamatzky, Andrew

    2014-01-01

    Neuromorphic computing is a brainlike information processing paradigm that requires adaptive learning mechanisms. A spiking neuro-evolutionary system is used for this purpose; plastic resistive memories are implemented as synapses in spiking neural networks. The evolutionary design process exploits parameter self-adaptation and allows the topology and synaptic weights to be evolved for each network in an autonomous manner. Variable resistive memories are the focus of this research; each synapse has its own conductance profile which modifies the plastic behaviour of the device and may be altered during evolution. These variable resistive networks are evaluated on a noisy robotic dynamic-reward scenario against two static resistive memories and a system containing standard connections only. The results indicate that the extra behavioural degrees of freedom available to the networks incorporating variable resistive memories enable them to outperform the comparative synapse types. PMID:23614774

  6. Renal cell carcinoma: Evolving and emerging subtypes

    PubMed Central

    Crumley, Suzanne M; Divatia, Mukul; Truong, Luan; Shen, Steven; Ayala, Alberto G; Ro, Jae Y

    2013-01-01

    Our knowledge of renal cell carcinoma (RCC) is rapidly expanding. For those who diagnose and treat RCC, it is important to understand the new developments. In recent years, many new renal tumors have been described and defined, and our understanding of the biology and clinical correlates of these tumors is changing. Evolving concepts in Xp11 translocation carcinoma, mucinous tubular and spindle cell carcinoma, multilocular cystic clear cell RCC, and carcinoma associated with neuroblastoma are addressed within this review. Tubulocystic carcinoma, thyroid-like follicular carcinoma of kidney, acquired cystic disease-associated RCC, and clear cell papillary RCC are also described. Finally, candidate entities, including RCC with t(6;11) translocation, hybrid oncocytoma/chromophobe RCC, hereditary leiomyomatosis and RCC syndrome, and renal angiomyoadenomatous tumor are reviewed. Knowledge of these new entities is important for diagnosis, treatment and subsequent prognosis. This review provides a targeted summary of new developments in RCC. PMID:24364021

  7. Evolving olfactory systems on the fly.

    PubMed

    Ramdya, Pavan; Benton, Richard

    2010-07-01

    The detection of odour stimuli in the environment is universally important for primal behaviours such as feeding, mating, kin interactions and escape responses. Given the ubiquity of many airborne chemical signals and the similar organisation of animal olfactory circuits, a fundamental question in our understanding of the sense of smell is how species-specific behavioural responses to odorants can evolve. Recent comparative genomic, developmental and physiological studies are shedding light on this problem by providing insights into the genetic mechanisms that underlie anatomical and functional evolution of the olfactory system. Here we synthesise these data, with a particular focus on insect olfaction, to address how new olfactory receptors and circuits might arise and diverge, offering glimpses into how odour-evoked behaviours could adapt to an ever-changing chemosensory world.

  8. Evolving unipolar memristor spiking neural networks

    NASA Astrophysics Data System (ADS)

    Howard, David; Bull, Larry; De Lacy Costello, Ben

    2015-10-01

    Neuromorphic computing - brain-like computing in hardware - typically requires myriad complimentary metal oxide semiconductor spiking neurons interconnected by a dense mesh of nanoscale plastic synapses. Memristors are frequently cited as strong synapse candidates due to their statefulness and potential for low-power implementations. To date, plentiful research has focused on the bipolar memristor synapse, which is capable of incremental weight alterations and can provide adaptive self-organisation under a Hebbian learning scheme. In this paper, we consider the unipolar memristor synapse - a device capable of non-Hebbian switching between only two states (conductive and resistive) through application of a suitable input voltage - and discuss its suitability for neuromorphic systems. A self-adaptive evolutionary process is used to autonomously find highly fit network configurations. Experimentation on two robotics tasks shows that unipolar memristor networks evolve task-solving controllers faster than both bipolar memristor networks and networks containing constant non-plastic connections whilst performing at least comparably.

  9. Synchronization in evolving snowdrift game model

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Wu, L.; Zhu, S. Q.

    2009-06-01

    The interaction between the evolution of the game and the underlying network structure with evolving snowdrift game model is investigated. The constructed network follows a power-law degree distribution typically showing scale-free feature. The topological features of average path length, clustering coefficient, degree-degree correlations and the dynamical feature of synchronizability are studied. The synchronizability of the constructed networks changes by the interaction. It will converge to a certain value when sufficient new nodes are added. It is found that initial payoffs of nodes greatly affect the synchronizability. When initial payoffs for players are equal, low common initial payoffs may lead to more heterogeneity of the network and good synchronizability. When initial payoffs follow certain distributions, better synchronizability is obtained compared to equal initial payoff. The result is also true for phase synchronization of nonidentical oscillators.

  10. Hyperhidrosis: evolving concepts and a comprehensive review.

    PubMed

    Vorkamp, Tobias; Foo, Fung Joon; Khan, Sidra; Schmitto, Jan D; Wilson, Paul

    2010-10-01

    Hyperhidrosis (primary or secondary) describes a disorder of excessive sweating. It has a significant negative impact on quality of life and affects nearly 1% of the population living in the United Kingdom (UK). Axillary involvement is the most common affecting 80% of cases. A common link to these disorders is an extreme non-thermoregulatory sympathetic stimulus of exocrine sweat glands, mostly due to emotional stimuli. Non-surgical treatment involves topical medication, iontophoresis and systemic anti-cholinergics. More recently the use of intradermal botulinum toxin has gained popularity. Surgical treatment reserved for severe cases, not responding to conservative management involves local excision, curettage and thoracoscopic sympathectomy. Evolving concepts for treatment, risks and benefits are discussed in the paper herein. PMID:20709287

  11. A local-world evolving hypernetwork model

    NASA Astrophysics Data System (ADS)

    Yang, Guang-Yong; Liu, Jian-Guo

    2014-01-01

    Complex hypernetworks are ubiquitous in the real system. It is very important to investigate the evolution mechanisms. In this paper, we present a local-world evolving hypernetwork model by taking into account the hyperedge growth and local-world hyperedge preferential attachment mechanisms. At each time step, a newly added hyperedge encircles a new coming node and a number of nodes from a randomly selected local world. The number of the selected nodes from the local world obeys the uniform distribution and its mean value is m. The analytical and simulation results show that the hyperdegree approximately obeys the power-law form and the exponent of hyperdegree distribution is γ = 2 + 1/m. Furthermore, we numerically investigate the node degree, hyperedge degree, clustering coefficient, as well as the average distance, and find that the hypernetwork model shares the scale-free and small-world properties, which shed some light for deeply understanding the evolution mechanism of the real systems.

  12. The Evolving Theory of Evolutionary Radiations.

    PubMed

    Simões, M; Breitkreuz, L; Alvarado, M; Baca, S; Cooper, J C; Heins, L; Herzog, K; Lieberman, B S

    2016-01-01

    Evolutionary radiations have intrigued biologists for more than 100 years, and our understanding of the patterns and processes associated with these radiations continues to grow and evolve. Recently it has been recognized that there are many different types of evolutionary radiation beyond the well-studied adaptive radiations. We focus here on multifarious types of evolutionary radiations, paying special attention to the abiotic factors that might trigger diversification in clades. We integrate concepts such as exaptation, species selection, coevolution, and the turnover-pulse hypothesis (TPH) into the theoretical framework of evolutionary radiations. We also discuss other phenomena that are related to, but distinct from, evolutionary radiations that have relevance for evolutionary biology. PMID:26632984

  13. Evolving resistance among Gram-positive pathogens.

    PubMed

    Munita, Jose M; Bayer, Arnold S; Arias, Cesar A

    2015-09-15

    Antimicrobial therapy is a key component of modern medical practice and a cornerstone for the development of complex clinical interventions in critically ill patients. Unfortunately, the increasing problem of antimicrobial resistance is now recognized as a major public health threat jeopardizing the care of thousands of patients worldwide. Gram-positive pathogens exhibit an immense genetic repertoire to adapt and develop resistance to virtually all antimicrobials clinically available. As more molecules become available to treat resistant gram-positive infections, resistance emerges as an evolutionary response. Thus, antimicrobial resistance has to be envisaged as an evolving phenomenon that demands constant surveillance and continuous efforts to identify emerging mechanisms of resistance to optimize the use of antibiotics and create strategies to circumvent this problem. Here, we will provide a broad perspective on the clinical aspects of antibiotic resistance in relevant gram-positive pathogens with emphasis on the mechanistic strategies used by these organisms to avoid being killed by commonly used antimicrobial agents.

  14. Resiliently evolving supply-demand networks

    NASA Astrophysics Data System (ADS)

    Rubido, Nicolás; Grebogi, Celso; Baptista, Murilo S.

    2014-01-01

    The ability to design a transport network such that commodities are brought from suppliers to consumers in a steady, optimal, and stable way is of great importance for distribution systems nowadays. In this work, by using the circuit laws of Kirchhoff and Ohm, we provide the exact capacities of the edges that an optimal supply-demand network should have to operate stably under perturbations, i.e., without overloading. The perturbations we consider are the evolution of the connecting topology, the decentralization of hub sources or sinks, and the intermittence of supplier and consumer characteristics. We analyze these conditions and the impact of our results, both on the current United Kingdom power-grid structure and on numerically generated evolving archetypal network topologies.

  15. Language as an evolving word web.

    PubMed

    Dorogovtsev, S N; Mendes, J F

    2001-12-22

    Human language may be described as a complex network of linked words. In such a treatment, each distinct word in language is a vertex of this web, and interacting words in sentences are connected by edges. The empirical distribution of the number of connections of words in this network is of a peculiar form that includes two pronounced power-law regions. Here we propose a theory of the evolution of language, which treats language as a self-organizing network of interacting words. In the framework of this concept, we completely describe the observed word web structure without any fitting. We show that the two regimes in the distribution naturally emerge from the evolutionary dynamics of the word web. It follows from our theory that the size of the core part of language, the 'kernel lexicon', does not vary as language evolves.

  16. Microbial communities evolve faster in extreme environments

    PubMed Central

    Li, Sheng-Jin; Hua, Zheng-Shuang; Huang, Li-Nan; Li, Jie; Shi, Su-Hua; Chen, Lin-Xing; Kuang, Jia-Liang; Liu, Jun; Hu, Min; Shu, Wen-Sheng

    2014-01-01

    Evolutionary analysis of microbes at the community level represents a new research avenue linking ecological patterns to evolutionary processes, but remains insufficiently studied. Here we report a relative evolutionary rates (rERs) analysis of microbial communities from six diverse natural environments based on 40 metagenomic samples. We show that the rERs of microbial communities are mainly shaped by environmental conditions, and the microbes inhabiting extreme habitats (acid mine drainage, saline lake and hot spring) evolve faster than those populating benign environments (surface ocean, fresh water and soil). These findings were supported by the observation of more relaxed purifying selection and potentially frequent horizontal gene transfers in communities from extreme habitats. The mechanism of high rERs was proposed as high mutation rates imposed by stressful conditions during the evolutionary processes. This study brings us one stage closer to an understanding of the evolutionary mechanisms underlying the adaptation of microbes to extreme environments. PMID:25158668

  17. A study of massive and evolved galaxies at high redshift

    SciTech Connect

    Nayyeri, H.; Mobasher, B.; Hemmati, S.; De Barros, S.; Ferguson, H. C.; Wiklind, T.; Dahlen, T.; Kassin, S.; Koekemoer, A.; Dickinson, M.; Giavalisco, M.; Fontana, A.; Paris, D.; Ashby, M.; Willner, S.; Barro, G.; Guo, Y.; Hathi, N. P.; Dunlop, J. S.; Targett, T. A.

    2014-10-10

    We use data taken as part of Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) observations of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) to identify massive and evolved galaxies at 3 < z < 4.5. This is performed using the strength of the Balmer break feature at rest-frame 3648 Å, which is a diagnostic of the age of the stellar population in galaxies. Using the WFC3 H-band-selected catalog for the CANDELS GOODS-S field and deep multi-waveband photometry from optical (HST) to mid-infrared (Spitzer) wavelengths, we identify a population of old and evolved post-starburst galaxies based on the strength of their Balmer breaks (Balmer break galaxies, BBGs). The galaxies are also selected to be bright in rest-frame near-IR wavelengths and hence massive. We identify a total of 16 BBGs. Fitting the spectral energy distribution of the BBGs shows that the candidate galaxies have average estimated ages of ∼800 Myr and average stellar masses of ∼5 × 10{sup 10} M {sub ☉}, consistent with being old and massive systems. Two of our BBG candidates are also identified by the criteria that are sensitive to star-forming galaxies (Lyman break galaxy selection). We find a number density of ∼3.2 × 10{sup –5} Mpc{sup –3} for the BBGs, corresponding to a mass density of ∼2.0 × 10{sup 6} M {sub ☉} Mpc{sup –3} in the redshift range covering the survey. Given the old age and the passive evolution, it is argued that some of these objects formed the bulk of their mass only a few hundred million years after the big bang.

  18. Evolving circuits in seconds: experiments with a stand-alone board-level evolvable system

    NASA Technical Reports Server (NTRS)

    Stoica, A.; Zebulum, R. S.; Ferguson, M. I.; Keymeulen, D.; Duong, V.; Guo, X.

    2002-01-01

    The purpose of this paper is twofold: first, to illustrate a stand-alone board-level evolvable system (SABLES) and its performance, and second to illustrate some problems that occur during evolution with real hardware in the loop, or when the intention of the user is not completely reflected in the fitness function.

  19. How evolved psychological mechanisms empower cultural group selection.

    PubMed

    Henrich, Joseph; Boyd, Robert

    2016-01-01

    Driven by intergroup competition, social norms, beliefs, and practices can evolve in ways that more effectively tap into a wide variety of evolved psychological mechanisms to foster group-beneficial behavior. The more powerful such evolved mechanisms are, the more effectively culture can potentially harness and manipulate them to generate greater phenotypic variation across groups, thereby fueling cultural group selection. PMID:27561383

  20. Evolving Stories of Child Career Development

    ERIC Educational Resources Information Center

    Watson, Mark; Nota, Laura; McMahon, Mary

    2015-01-01

    Herein, the contributions to this special issue and positions the field of child career development in terms of its past, present, and future are considered. There is an initial brief overview of past developments in the field, specifically as described in seminal reviews. The article then considers the present status of and future agenda for the…

  1. Mercury-T: Tidally evolving multi-planet systems code

    NASA Astrophysics Data System (ADS)

    Bolmont, Emeline; Raymond, Sean N.; Leconte, Jeremy; Hersant, Franck; Correia, Alexandre C. M.

    2015-11-01

    Mercury-T calculates the evolution of semi-major axis, eccentricity, inclination, rotation period and obliquity of the planets as well as the rotation period evolution of the host body; it is based on the N-body code Mercury (Chambers 1999, ascl:1201.008). It is flexible, allowing computation of the tidal evolution of systems orbiting any non-evolving object (if its mass, radius, dissipation factor and rotation period are known), but also evolving brown dwarfs (BDs) of mass between 0.01 and 0.08 M⊙, an evolving M-dwarf of 0.1 M⊙, an evolving Sun-like star, and an evolving Jupiter.

  2. Speciation genetics: current status and evolving approaches

    PubMed Central

    Wolf, Jochen B. W.; Lindell, Johan; Backström, Niclas

    2010-01-01

    The view of species as entities subjected to natural selection and amenable to change put forth by Charles Darwin and Alfred Wallace laid the conceptual foundation for understanding speciation. Initially marred by a rudimental understanding of hereditary principles, evolutionists gained appreciation of the mechanistic underpinnings of speciation following the merger of Mendelian genetic principles with Darwinian evolution. Only recently have we entered an era where deciphering the molecular basis of speciation is within reach. Much focus has been devoted to the genetic basis of intrinsic postzygotic isolation in model organisms and several hybrid incompatibility genes have been successfully identified. However, concomitant with the recent technological advancements in genome analysis and a newfound interest in the role of ecology in the differentiation process, speciation genetic research is becoming increasingly open to non-model organisms. This development will expand speciation research beyond the traditional boundaries and unveil the genetic basis of speciation from manifold perspectives and at various stages of the splitting process. This review aims at providing an extensive overview of speciation genetics. Starting from key historical developments and core concepts of speciation genetics, we focus much of our attention on evolving approaches and introduce promising methodological approaches for future research venues. PMID:20439277

  3. The Evolving Role of Midwives as Laborists.

    PubMed

    DeJoy, Susan A; Sankey, Heather Z; Dickerson, Anissa E; Psaltis, Audrey; Galli, Amy; Burkman, Ronald T

    2015-01-01

    This article examines the history and present state of the midwife as laborist. The role of the midwife and obstetrician laborist/hospitalist is rapidly evolving due to the need to improve patient safety and provide direct care due to reduced resident work hours, as well as practice demands experienced by community providers and other factors. Models under development are customized to meet the needs of different communities and hospitals. Midwives are playing a prominent role in many laborist/hospitalist practices as the first-line hospital provider or as part of a team with physicians. Some models incorporate certified nurse-midwives/certified midwives as faculty to residents and medical students. The midwifery laborist/hospitalist practices at Baystate Medical Center in Springfield, Massachusetts, are presented as an example of how midwives are functioning as laborists. Essential components of a successful midwife laborist program include interdisciplinary planning, delineation of problems the model should solve, establishment of program metrics, clear practice guidelines and role definitions, and a plan for sustained funding. This article is part of a special series of articles that address midwifery innovations in clinical practice, education, interprofessional collaboration, health policy, and global health. PMID:26619374

  4. Are Electronic Cardiac Devices Still Evolving?

    PubMed Central

    Mabo, P.

    2014-01-01

    Summary Objectives The goal of this paper is to review some important issues occurring during the past year in Implantable devices. Methods First cardiac implantable device was proposed to maintain an adequate heart rate, either because the heart’s natural pacemaker is not fast enough, or there is a block in the heart’s electrical conduction system. During the last forty years, pacemakers have evolved considerably and become programmable and allow to configure specific patient optimum pacing modes. Various technological aspects (electrodes, connectors, algorithms diagnosis, therapies, …) have been progressed and cardiac implants address several clinical applications: management of arrhythmias, cardioversion / defibrillation and cardiac resynchronization therapy. Results Observed progress was the miniaturization of device, increased longevity, coupled with efficient pacing functions, multisite pacing modes, leadless pacing and also a better recognition of supraventricular or ventricular tachycardia’s in order to deliver appropriate therapy. Subcutaneous implant, new modes of stimulation (leadless implant or ultrasound lead), quadripolar lead and new sensor or new algorithm for the hemodynamic management are introduced and briefly described. Each times, the main result occurring during the two past years are underlined and repositioned from the history, remaining limitations are also addressed. Conclusion Some important technological improvements were described. Nevertheless, news trends for the future are also considered in a specific session such as the remote follow-up of the patient or the treatment of heart failure by neuromodulation. PMID:25123732

  5. Women and Ischemic Heart Disease: Evolving Knowledge

    PubMed Central

    Shaw, Leslee J.; Bugiardini, Raffaelle; Merz, C. Noel Bairey

    2009-01-01

    Evolving knowledge regarding sex differences in coronary heart disease (CHD) is emerging. Given the lower burden of obstructive coronary artery disease (CAD) and preserved systolic function in women contrasted by higher rates of myocardial ischemia and near-term mortality compared to men, we propose the term ischemic heart disease (IHD) as appropriate for this discussion specific to women, rather than CAD or CHD. This paradoxical difference where women have lower rates of anatomical CAD but more symptoms, ischemia, and outcomes appear linked to coronary reactivity which includes microvascular dysfunction. Novel risk factors can improve the Framingham risk score, including inflammatory markers and reproductive hormones, as well as noninvasive imaging and functional capacity measurements. Risk for women with obstructive CAD is elevated compared to men, yet women are less likely to receive guideline-indicated therapies. In the setting of non-ST elevation acute myocardial infarction, interventional strategies are equally effective in biomarker positive women and men, while conservative management is indicated for biomarker negative women. For women with evidence of ischemia but no obstructive CAD, anti-anginal and anti-ischemic therapies can improve symptoms, endothelial function, and quality of life; however trials evaluating adverse outcomes are needed. We hypothesize that women experience more adverse outcomes compared to men because obstructive CAD remains the current focus of therapeutic strategies. Continued research is indicated to devise therapeutic regimens to improve symptom burden and reduce risk in women with IHD. PMID:19833255

  6. Evolving Earth Models and Nuclear Explosion Monitoring

    NASA Astrophysics Data System (ADS)

    Wallace, T. C.

    2003-12-01

    One of the most important problems in nuclear explosion monitoring is accurate seismic event location. Traditional location methods rely on estimating travel times in a known Earth model and accounting for heterogeneity through various empirical corrections. The history of location accuracy and precision is closely coupled to evolving theories of the nature of the Earth's interior. LONG SHOT was a 80 Kt explosion conducted on Amchitka Island on October 29, 1965. The travel times recorded from LONG SHOT deviated strongly from a radially symmetric Earth, and in fact showed a pattern consistent a tabular body of relatively high seismic velocity (the subducting North American Plate) validating certain concepts of the then new theory of plate tectonics. Each subsequent advance in conceptual models for the dynamics of the Earth's interior has impacted explosion monitoring. Many of the advances in the theory of the Earth's interior have been spurred by the ideas and work of Don Anderson. These include anelasticity, anisotropy, tomography, the Lehmann discontinuity, and mantle plumes (or lack of). The present state-of-the-art monitoring paradigm incorporates a dynamic Earth model, and the synergy between verification research and basic research on the Earth's interior is quite important.

  7. Evolving Resistance Among Gram-positive Pathogens

    PubMed Central

    Munita, Jose M.; Bayer, Arnold S.; Arias, Cesar A.

    2015-01-01

    Antimicrobial therapy is a key component of modern medical practice and a cornerstone for the development of complex clinical interventions in critically ill patients. Unfortunately, the increasing problem of antimicrobial resistance is now recognized as a major public health threat jeopardizing the care of thousands of patients worldwide. Gram-positive pathogens exhibit an immense genetic repertoire to adapt and develop resistance to virtually all antimicrobials clinically available. As more molecules become available to treat resistant gram-positive infections, resistance emerges as an evolutionary response. Thus, antimicrobial resistance has to be envisaged as an evolving phenomenon that demands constant surveillance and continuous efforts to identify emerging mechanisms of resistance to optimize the use of antibiotics and create strategies to circumvent this problem. Here, we will provide a broad perspective on the clinical aspects of antibiotic resistance in relevant gram-positive pathogens with emphasis on the mechanistic strategies used by these organisms to avoid being killed by commonly used antimicrobial agents. PMID:26316558

  8. Tearing Mode Stability of Evolving Toroidal Equilibria

    NASA Astrophysics Data System (ADS)

    Pletzer, A.; McCune, D.; Manickam, J.; Jardin, S. C.

    2000-10-01

    There are a number of toroidal equilibrium (such as JSOLVER, ESC, EFIT, and VMEC) and transport codes (such as TRANSP, BALDUR, and TSC) in our community that utilize differing equilibrium representations. There are also many heating and current drive (LSC and TORRAY), and stability (PEST1-3, GATO, NOVA, MARS, DCON, M3D) codes that require this equilibrium information. In an effort to provide seamless compatibility between the codes that produce and need these equilibria, we have developed two Fortran 90 modules, MEQ and XPLASMA, that serve as common interfaces between these two classes of codes. XPLASMA provides a common equilibrium representation for the heating and current drive applications while MEQ provides common equilibrium and associated metric information needed by MHD stability codes. We illustrate the utility of this approach by presenting results of PEST-3 tearing stability calculations of an NSTX discharge performed on profiles provided by the TRANSP code. Using the MEQ module, the TRANSP equilibrium data are stored in a Fortran 90 derived type and passed to PEST3 as a subroutine argument. All calculations are performed on the fly, as the profiles evolve.

  9. Origins of stereoselectivity in evolved ketoreductases

    PubMed Central

    Noey, Elizabeth L.; Tibrewal, Nidhi; Jiménez-Osés, Gonzalo; Osuna, Sílvia; Park, Jiyong; Bond, Carly M.; Cascio, Duilio; Liang, Jack; Zhang, Xiyun; Huisman, Gjalt W.; Tang, Yi; Houk, Kendall N.

    2015-01-01

    Mutants of Lactobacillus kefir short-chain alcohol dehydrogenase, used here as ketoreductases (KREDs), enantioselectively reduce the pharmaceutically relevant substrates 3-thiacyclopentanone and 3-oxacyclopentanone. These substrates differ by only the heteroatom (S or O) in the ring, but the KRED mutants reduce them with different enantioselectivities. Kinetic studies show that these enzymes are more efficient with 3-thiacyclopentanone than with 3-oxacyclopentanone. X-ray crystal structures of apo- and NADP+-bound selected mutants show that the substrate-binding loop conformational preferences are modified by these mutations. Quantum mechanical calculations and molecular dynamics (MD) simulations are used to investigate the mechanism of reduction by the enzyme. We have developed an MD-based method for studying the diastereomeric transition state complexes and rationalize different enantiomeric ratios. This method, which probes the stability of the catalytic arrangement within the theozyme, shows a correlation between the relative fractions of catalytically competent poses for the enantiomeric reductions and the experimental enantiomeric ratio. Some mutations, such as A94F and Y190F, induce conformational changes in the active site that enlarge the small binding pocket, facilitating accommodation of the larger S atom in this region and enhancing S-selectivity with 3-thiacyclopentanone. In contrast, in the E145S mutant and the final variant evolved for large-scale production of the intermediate for the antibiotic sulopenem, R-selectivity is promoted by shrinking the small binding pocket, thereby destabilizing the pro-S orientation. PMID:26644568

  10. An evolving model of online bipartite networks

    NASA Astrophysics Data System (ADS)

    Zhang, Chu-Xu; Zhang, Zi-Ke; Liu, Chuang

    2013-12-01

    Understanding the structure and evolution of online bipartite networks is a significant task since they play a crucial role in various e-commerce services nowadays. Recently, various attempts have been tried to propose different models, resulting in either power-law or exponential degree distributions. However, many empirical results show that the user degree distribution actually follows a shifted power-law distribution, the so-called Mandelbrot’s law, which cannot be fully described by previous models. In this paper, we propose an evolving model, considering two different user behaviors: random and preferential attachment. Extensive empirical results on two real bipartite networks, Delicious and CiteULike, show that the theoretical model can well characterize the structure of real networks for both user and object degree distributions. In addition, we introduce a structural parameter p, to demonstrate that the hybrid user behavior leads to the shifted power-law degree distribution, and the region of power-law tail will increase with the increment of p. The proposed model might shed some lights in understanding the underlying laws governing the structure of real online bipartite networks.

  11. Regulatory mechanisms link phenotypic plasticity to evolvability

    PubMed Central

    van Gestel, Jordi; Weissing, Franz J.

    2016-01-01

    Organisms have a remarkable capacity to respond to environmental change. They can either respond directly, by means of phenotypic plasticity, or they can slowly adapt through evolution. Yet, how phenotypic plasticity links to evolutionary adaptability is largely unknown. Current studies of plasticity tend to adopt a phenomenological reaction norm (RN) approach, which neglects the mechanisms underlying plasticity. Focusing on a concrete question – the optimal timing of bacterial sporulation – we here also consider a mechanistic approach, the evolution of a gene regulatory network (GRN) underlying plasticity. Using individual-based simulations, we compare the RN and GRN approach and find a number of striking differences. Most importantly, the GRN model results in a much higher diversity of responsive strategies than the RN model. We show that each of the evolved strategies is pre-adapted to a unique set of unseen environmental conditions. The regulatory mechanisms that control plasticity therefore critically link phenotypic plasticity to the adaptive potential of biological populations. PMID:27087393

  12. Gastric cancer: current and evolving treatment landscape.

    PubMed

    Sun, Weijing; Yan, Li

    2016-01-01

    Gastric (including gastroesophageal junction) cancer is the third leading cause of cancer-related death in the world. In China, an estimated 420,000 patients were diagnosed with gastric cancer in 2011, ranking this malignancy the second most prevalent cancer type and resulting in near 300,000 deaths. The treatment landscape of gastric cancer has evolved in recent years. Although systemic chemotherapy is still the mainstay treatment of metastatic disease, the introduction of agents targeting human epidermal growth factor receptor 2 and vascular endothelial growth factor/vascular endothelia growth factor receptor has brought this disease into the molecular and personalized medicine era. The preliminary yet encouraging clinical efficacy observed with immune checkpoint inhibitors, e.g., anti-programmed cell death protein 1/programmed death-ligand 1, will further shape the treatment landscape for gastric cancer. Molecular characterization of patients will play a critical role in developing new agents, as well as in implementing new treatment options for this disease. PMID:27581465

  13. Relatedness influences signal reliability in evolving robots.

    PubMed

    Mitri, Sara; Floreano, Dario; Keller, Laurent

    2011-02-01

    Communication is an indispensable component of animal societies, yet many open questions remain regarding the factors affecting the evolution and reliability of signalling systems. A potentially important factor is the level of genetic relatedness between signallers and receivers. To quantitatively explore the role of relatedness in the evolution of reliable signals, we conducted artificial evolution over 500 generations in a system of foraging robots that can emit and perceive light signals. By devising a quantitative measure of signal reliability, and comparing independently evolving populations differing in within-group relatedness, we show a strong positive correlation between relatedness and reliability. Unrelated robots produced unreliable signals, whereas highly related robots produced signals that reliably indicated the location of the food source and thereby increased performance. Comparisons across populations also revealed that the frequency for signal production-which is often used as a proxy of signal reliability in empirical studies on animal communication-is a poor predictor of signal reliability and, accordingly, is not consistently correlated with group performance. This has important implications for our understanding of signal evolution and the empirical tools that are used to investigate communication.

  14. Exploring Evolving Media Discourse Through Event Cueing.

    PubMed

    Lu, Yafeng; Steptoe, Michael; Burke, Sarah; Wang, Hong; Tsai, Jiun-Yi; Davulcu, Hasan; Montgomery, Douglas; Corman, Steven R; Maciejewski, Ross

    2016-01-01

    Online news, microblogs and other media documents all contain valuable insight regarding events and responses to events. Underlying these documents is the concept of framing, a process in which communicators act (consciously or unconsciously) to construct a point of view that encourages facts to be interpreted by others in a particular manner. As media discourse evolves, how topics and documents are framed can undergo change, shifting the discussion to different viewpoints or rhetoric. What causes these shifts can be difficult to determine directly; however, by linking secondary datasets and enabling visual exploration, we can enhance the hypothesis generation process. In this paper, we present a visual analytics framework for event cueing using media data. As discourse develops over time, our framework applies a time series intervention model which tests to see if the level of framing is different before or after a given date. If the model indicates that the times before and after are statistically significantly different, this cues an analyst to explore related datasets to help enhance their understanding of what (if any) events may have triggered these changes in discourse. Our framework consists of entity extraction and sentiment analysis as lenses for data exploration and uses two different models for intervention analysis. To demonstrate the usage of our framework, we present a case study on exploring potential relationships between climate change framing and conflicts in Africa.

  15. Metapopulation capacity of evolving fluvial landscapes

    NASA Astrophysics Data System (ADS)

    Bertuzzo, Enrico; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2015-04-01

    The form of fluvial landscapes is known to attain stationary network configurations that settle in dynamically accessible minima of total energy dissipation by landscape-forming discharges. Recent studies have highlighted the role of the dendritic structure of river networks in controlling population dynamics of the species they host and large-scale biodiversity patterns. Here, we systematically investigate the relation between energy dissipation, the physical driver for the evolution of river networks, and the ecological dynamics of their embedded biota. To that end, we use the concept of metapopulation capacity, a measure to link landscape structures with the population dynamics they host. Technically, metapopulation capacity is the leading eigenvalue λM of an appropriate "landscape" matrix subsuming whether a given species is predicted to persist in the long run. λM can conveniently be used to rank different landscapes in terms of their capacity to support viable metapopulations. We study how λM changes in response to the evolving network configurations of spanning trees. Such sequence of configurations is theoretically known to relate network selection to general landscape evolution equations through imperfect searches for dynamically accessible states frustrated by the vagaries of Nature. Results show that the process shaping the metric and the topological properties of river networks, prescribed by physical constraints, leads to a progressive increase in the corresponding metapopulation capacity and therefore on the landscape capacity to support metapopulations—with implications on biodiversity in fluvial ecosystems.

  16. Generative Representations for Evolving Families of Designs

    NASA Technical Reports Server (NTRS)

    Hornby, Gregory S.

    2003-01-01

    Since typical evolutionary design systems encode only a single artifact with each individual, each time the objective changes a new set of individuals must be evolved. When this objective varies in a way that can be parameterized, a more general method is to use a representation in which a single individual encodes an entire class of artifacts. In addition to saving time by preventing the need for multiple evolutionary runs, the evolution of parameter-controlled designs can create families of artifacts with the same style and a reuse of parts between members of the family. In this paper an evolutionary design system is described which uses a generative representation to encode families of designs. Because a generative representation is an algorithmic encoding of a design, its input parameters are a way to control aspects of the design it generates. By evaluating individuals multiple times with different input parameters the evolutionary design system creates individuals in which the input parameter controls specific aspects of a design. This system is demonstrated on two design substrates: neural-networks which solve the 3/5/7-parity problem and three-dimensional tables of varying heights.

  17. How does cognition evolve? Phylogenetic comparative psychology

    PubMed Central

    Matthews, Luke J.; Hare, Brian A.; Nunn, Charles L.; Anderson, Rindy C.; Aureli, Filippo; Brannon, Elizabeth M.; Call, Josep; Drea, Christine M.; Emery, Nathan J.; Haun, Daniel B. M.; Herrmann, Esther; Jacobs, Lucia F.; Platt, Michael L.; Rosati, Alexandra G.; Sandel, Aaron A.; Schroepfer, Kara K.; Seed, Amanda M.; Tan, Jingzhi; van Schaik, Carel P.; Wobber, Victoria

    2014-01-01

    Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution. PMID:21927850

  18. Evolving application of biomimetic nanostructured hydroxyapatite

    PubMed Central

    Roveri, Norberto; Iafisco, Michele

    2010-01-01

    By mimicking Nature, we can design and synthesize inorganic smart materials that are reactive to biological tissues. These smart materials can be utilized to design innovative third-generation biomaterials, which are able to not only optimize their interaction with biological tissues and environment, but also mimic biogenic materials in their functionalities. The biomedical applications involve increasing the biomimetic levels from chemical composition, structural organization, morphology, mechanical behavior, nanostructure, and bulk and surface chemical–physical properties until the surface becomes bioreactive and stimulates cellular materials. The chemical–physical characteristics of biogenic hydroxyapatites from bone and tooth have been described, in order to point out the elective sides, which are important to reproduce the design of a new biomimetic synthetic hydroxyapatite. This review outlines the evolving applications of biomimetic synthetic calcium phosphates, details the main characteristics of bone and tooth, where the calcium phosphates are present, and discusses the chemical–physical characteristics of biomimetic calcium phosphates, methods of synthesizing them, and some of their biomedical applications. PMID:24198477

  19. Speciation genetics: current status and evolving approaches.

    PubMed

    Wolf, Jochen B W; Lindell, Johan; Backström, Niclas

    2010-06-12

    The view of species as entities subjected to natural selection and amenable to change put forth by Charles Darwin and Alfred Wallace laid the conceptual foundation for understanding speciation. Initially marred by a rudimental understanding of hereditary principles, evolutionists gained appreciation of the mechanistic underpinnings of speciation following the merger of Mendelian genetic principles with Darwinian evolution. Only recently have we entered an era where deciphering the molecular basis of speciation is within reach. Much focus has been devoted to the genetic basis of intrinsic postzygotic isolation in model organisms and several hybrid incompatibility genes have been successfully identified. However, concomitant with the recent technological advancements in genome analysis and a newfound interest in the role of ecology in the differentiation process, speciation genetic research is becoming increasingly open to non-model organisms. This development will expand speciation research beyond the traditional boundaries and unveil the genetic basis of speciation from manifold perspectives and at various stages of the splitting process. This review aims at providing an extensive overview of speciation genetics. Starting from key historical developments and core concepts of speciation genetics, we focus much of our attention on evolving approaches and introduce promising methodological approaches for future research venues.

  20. Evolving paradigms in multifocal breast cancer.

    PubMed

    Salgado, Roberto; Aftimos, Philippe; Sotiriou, Christos; Desmedt, Christine

    2015-04-01

    The 7th edition of the TNM defines multifocal breast cancer as multiple simultaneous ipsilateral and synchronous breast cancer lesions, provided they are macroscopically distinct and measurable using current traditional pathological and clinical tools. According to the College of American Pathologists (CAP), the characterization of only the largest lesion is considered sufficient, unless the grade and/or histology are different between the lesions. Here, we review three potentially clinically relevant aspects of multifocal breast cancers: first, the importance of a different intrinsic breast cancer subtype of the various lesions; second, the emerging awareness of inter-lesion heterogeneity; and last but not least, the potential introduction of bias in clinical trials due to the unrecognized biological diversity of these cancers. Although the current strategy to assess the lesion with the largest diameter has clearly its advantages in terms of costs and feasibility, this recommendation may not be sustainable in time and might need to be adapted to be compliant with new evolving paradigms in breast cancer.

  1. Origins and evolvability of the PAX family.

    PubMed

    Paixão-Côrtes, Vanessa R; Salzano, Francisco M; Bortolini, Maria Cátira

    2015-08-01

    The paired box (PAX) family of transcription/developmental genes plays a key role in numerous stages of embryonic development, as well as in adult organogenesis. There is evidence linking the acquisition of a paired-like DNA binding domain (PD) to domestication of a Tc1/mariner transposon. Further duplication/deletion processes led to at least five paralogous metazoan protein groups, which can be classified into two supergroups, PAXB-like or PAXD-like, using ancestral defining structures; the PD plus an octapeptide motif (OP) and a paired-type homeobox DNA binding domain (PTHD), producing the PD-OP-PTHD structure characteristic of the PAXB-like group, whereas an additional domain, the paired-type homeodomain tail (PHT), is present in the PAXD-like group, producing a PD-OP-PTHD-PHT structure. We examined their patterns of distribution in various species, using both available data and new bioinformatic analyses, including vertebrate PAX genes and their shared and specific functions, as well as inter- and intraspecific variability of PAX in primates. These analyses revealed a relatively conserved PAX network, accompanied by specific changes that led to adaptive novelties. Therefore, both stability and evolvability shaped the molecular evolution of this key transcriptional network. PMID:26321496

  2. Evolving role of MRI in Crohn's disease.

    PubMed

    Yacoub, Joseph H; Obara, Piotr; Oto, Aytekin

    2013-06-01

    MR enterography is playing an evolving role in the evaluation of small bowel Crohn's disease (CD). Standard MR enterography includes a combination of rapidly acquired T2 sequence, balanced steady-state acquisition, and contrast enhanced T1-weighted gradient echo sequence. The diagnostic performance of these sequences has been shown to be comparable, and in some respects superior, to other small bowel imaging modalities. The findings of CD on MR enterography have been well described in the literature. New and emerging techniques such as diffusion-weighted imaging (DWI), dynamic contrast enhanced MRI (DCE-MRI), cinematography, and magnetization transfer, may lead to improved accuracy in characterizing the disease. These advanced techniques can provide quantitative parameters that may prove to be useful in assessing disease activity, severity, and response to treatment. In the future, MR enterography may play an increasing role in management decisions for patients with small bowel CD; however, larger studies are needed to validate these emerging MRI parameters as imaging biomarkers. PMID:23712842

  3. Lower mass limit of an evolving interstellar cloud and chemistry in an evolving oscillatory cloud

    NASA Technical Reports Server (NTRS)

    Tarafdar, S. P.

    1986-01-01

    Simultaneous solution of the equation of motion, equation of state and energy equation including heating and cooling processes for interstellar medium gives for a collapsing cloud a lower mass limit which is significantly smaller than the Jeans mass for the same initial density. The clouds with higher mass than this limiting mass collapse whereas clouds with smaller than critical mass pass through a maximum central density giving apparently similar clouds (i.e., same Av, size and central density) at two different phases of its evolution (i.e., with different life time). Preliminary results of chemistry in such an evolving oscillatory cloud show significant difference in abundances of some of the molecules in two physically similar clouds with different life times. The problems of depletion and short life time of evolving clouds appear to be less severe in such an oscillatory cloud.

  4. Implementing a spinosad-based local bait station to control Bactrocera cucurbitae (Diptera: Tephritidae) in high rainfall areas of Reunion Island.

    PubMed

    Delpoux, Camille; Deguine, Jean-Philippe

    2015-01-01

    Three species of fruit flies cause serious damage to cucurbit crops on Reunion Island: Bactrocera cucurbitae (Diptera: Tephritidae) (Coquillett 1899), Dacus ciliatus (Loew 1901), and Dacus demmerezi (Bezzi 1917). To control them, a program of agroecological management of cucurbit flies has been implemented based on the application of Synéis-appât, especially spot sprays on corn borders. However, the high rainfall on Reunion Island limits the long-term efficiency of the bait; in addition, this method cannot be used for large chayote trellises, because corn borders cannot be planted around them. The aim of this study was to design a bait station adapted to prevailing conditions on Reunion Island. An 'umbrella trap' tested in Taiwan was used as a reference to compare its efficacy with our local bait station. Experiments were conducted in field cages on B. cucurbitae to test different characteristics of bait stations and to construct one using local materials. Results were validated in the field. The attractiveness of the bait station was related mainly to the color of the external surface, yellow being the most attractive color. The efficacy of the bait station with respect to fly mortality was found to be linked to the accessibility of the bait, and direct application of Synéis-appât on the bait station was found to be the most efficient. In the field, B. cucurbitae were more attracted to the local bait station than to the umbrella trap, while the two other fly species displayed equal attraction to both trap types. Our local bait station is a useful alternative to spot sprays of Synéis-appât and is now included in a local pest management program and is well accepted by farmers. PMID:25688089

  5. Implementing a Spinosad-Based Local Bait Station to Control Bactrocera cucurbitae (Diptera: Tephritidae) in High Rainfall Areas of Reunion Island

    PubMed Central

    Delpoux, Camille; Deguine, Jean-Philippe

    2015-01-01

    Three species of fruit flies cause serious damage to cucurbit crops on Reunion Island: Bactrocera cucurbitae (Diptera: Tephritidae) (Coquillett 1899), Dacus ciliatus (Loew 1901), and Dacus demmerezi (Bezzi 1917). To control them, a program of agroecological management of cucurbit flies has been implemented based on the application of Synéis-appât, especially spot sprays on corn borders. However, the high rainfall on Reunion Island limits the long-term efficiency of the bait; in addition, this method cannot be used for large chayote trellises, because corn borders cannot be planted around them. The aim of this study was to design a bait station adapted to prevailing conditions on Reunion Island. An ‘umbrella trap’ tested in Taiwan was used as a reference to compare its efficacy with our local bait station. Experiments were conducted in field cages on B. cucurbitae to test different characteristics of bait stations and to construct one using local materials. Results were validated in the field. The attractiveness of the bait station was related mainly to the color of the external surface, yellow being the most attractive color. The efficacy of the bait station with respect to fly mortality was found to be linked to the accessibility of the bait, and direct application of Synéis-appât on the bait station was found to be the most efficient. In the field, B. cucurbitae were more attracted to the local bait station than to the umbrella trap, while the two other fly species displayed equal attraction to both trap types. Our local bait station is a useful alternative to spot sprays of Synéis-appât and is now included in a local pest management program and is well accepted by farmers. PMID:25688089

  6. Early-branching or fast-evolving eukaryotes? An answer based on slowly evolving positions.

    PubMed

    Philippe, H; Lopez, P; Brinkmann, H; Budin, K; Germot, A; Laurent, J; Moreira, D; Müller, M; Le Guyader, H

    2000-06-22

    The current paradigm of eukaryotic evolution is based primarily on comparative analysis of ribosomal RNA sequences. It shows several early-emerging lineages, mostly amitochondriate, which might be living relics of a progressive assembly of the eukaryotic cell. However, the analysis of slow-evolving positions, carried out with the newly developed slow-fast method, reveals that these lineages are, in terms of nucleotide substitution, fast-evolving ones, misplaced at the base of the tree by a long branch attraction artefact. Since the fast-evolving groups are not always the same, depending on which macromolecule is used as a marker, this explains most of the observed incongruent phylogenies. The current paradigm of eukaryotic evolution thus has to be seriously re-examined as the eukaryotic phylogeny is presently best summarized by a multifurcation. This is consistent with the Big Bang hypothesis that all extant eukaryotic lineages are the result of multiple cladogeneses within a relatively brief period, although insufficiency of data is also a possible explanation for the lack of resolution. For further resolution, rare evolutionary events such as shared insertions and/or deletions or gene fusions might be helpful.

  7. Early-branching or fast-evolving eukaryotes? An answer based on slowly evolving positions.

    PubMed Central

    Philippe, H; Lopez, P; Brinkmann, H; Budin, K; Germot, A; Laurent, J; Moreira, D; Müller, M; Le Guyader, H

    2000-01-01

    The current paradigm of eukaryotic evolution is based primarily on comparative analysis of ribosomal RNA sequences. It shows several early-emerging lineages, mostly amitochondriate, which might be living relics of a progressive assembly of the eukaryotic cell. However, the analysis of slow-evolving positions, carried out with the newly developed slow-fast method, reveals that these lineages are, in terms of nucleotide substitution, fast-evolving ones, misplaced at the base of the tree by a long branch attraction artefact. Since the fast-evolving groups are not always the same, depending on which macromolecule is used as a marker, this explains most of the observed incongruent phylogenies. The current paradigm of eukaryotic evolution thus has to be seriously re-examined as the eukaryotic phylogeny is presently best summarized by a multifurcation. This is consistent with the Big Bang hypothesis that all extant eukaryotic lineages are the result of multiple cladogeneses within a relatively brief period, although insufficiency of data is also a possible explanation for the lack of resolution. For further resolution, rare evolutionary events such as shared insertions and/or deletions or gene fusions might be helpful. PMID:10902687

  8. Molecular line emission in asymmetric envelopes of evolved stars

    NASA Astrophysics Data System (ADS)

    Sanchez, Andres Felipe Perez

    2014-06-01

    Stars with initial masses of 0.8 < M⊙ < 9M⊙ eject most of their mass when evolving along the asymptotic giant branch (AGB) phase. The ejected material eventually cools down, which leads it to condensate and to form dust grains and molecular gas around the star, creating an extended circumstellar envelope (CSE). The mechanism responsible for the expansion of the dusty and dense CSEs is not completely understood. It is suggested that stellar radiation pressure on the dust particles can accelerate them outwards. Then, by collisional exchange of momentum, the dust particles drag along the molecular gas. However, this scenario cannot explain the onset of asymmetries in the CSEs observed towards more evolved sources such as post-AGB sources and Planetary nebulae. Part of the research in this thesis is focused on the study of the role that the stellar magnetic field plays on the formation of the collimated high-velocity outflows observed towards post-AGB sources. Polarized maser emission towards (post-)AGB stars has become an useful tool to determine the properties of the stellar magnetic fields permeating their CSEs. However, the polarization fraction detected can be affected by non-Zeeman effects. Here I present the results of our analysis of the polarization properties of SiO, H2O and HCN maser emission in the (sub-)millimetre wavelength range. The goal of this analysis is to determine whether polarized maser emission of these molecular species can be used as reliable tracer of the magnetic field from observations at (sub-)millimetre wavelengths. I also present the results of radio interferometric observations of both continuum and polarized maser emission towards post-AGB stars. The sources observed are characterized by H2O maser emission arising from their collimated, high-velocity outflows. The observations have been carried out with the Australian Telescope Compact Array aiming to detect both polarized maser emission and non-thermal radio continuum emission

  9. Summary of the Conference "The Physics of Evolved Stars"

    NASA Astrophysics Data System (ADS)

    De Marco, O.

    2015-12-01

    Olivier Chesneau was an astronomer of many talents. His expertise was on optical and infrared interferometry. Olivier*s tool of choice, the Very Large Telescope Interferometer (VLTI), allowed him to see solutions to open questions in stellar astrophysics. These visions led to collaborations with experts in each of the fields where VLTI observations could be useful. As a result Olivier was a man in the middle of a phenomenal network of astronomers, collaborators and friends. I am fortunate to have been one of them. In this contribution I summarise the conference "Physics of Evolved Stars", held in Nice in June 2015 in memory of Olivier. The conference neatly showcased the science that Olivier had been involved with during his life and laid out the advancements that were made thanks in great part to him and to the collaborations he started. Without doubt his bubbly, happy personality, child-like in a way, made him the perfect connector bringing the technique, the questions and the experts in diverse fields together. Dear to all who worked with him, he was truly the little prince of Astronomy. We shall miss him every day.

  10. Coronal Modeling with Flux-Evolved Maps: Comparison with Observations

    NASA Astrophysics Data System (ADS)

    Linker, J.; Downs, C.; Lionello, R.; Caplan, R. M.; Mikic, Z.; Riley, P.; Henney, C. J.; Arge, C. N.

    2014-12-01

    MHD simulations of the solar corona rely on maps of the solar magnetic field for input as boundary conditions. These "synoptic" maps (available from a number of ground-based and space-based solar observatories) are built up over a solar rotation. A well-known problem with this approach is that the maps contain data that is as much as 27 days old. The Sun's magnetic flux is always evolving, and these changes in the flux affect coronal and heliospheric structure. Flux evolution models can in principle provide a more accurate specification, by estimating the likely state of the photospheric magnetic field on unobserved portions of the Sun. The Air Force Data Assimilative Photospheric flux Transport (ADAPT) model (Arge et al. 2010) is especially well suited for this purpose. ADAPT can also incorporate information from helioseismic acoustic images to estimate the emergence of new active regions on the Sun's far side. In this presentation we describe MHD models with boundary conditions derived from ADAPT maps. We investigate the June-August 2010 time period, when there was significant coronal hole evolution observed by the STEREO and SDO spacecraft. We compare model results using ADAPT maps, including those with far side data, as well as models using traditional synoptic maps, to STEREO EUVI and SDO AIA data. Research supported by AFOSR & NASA.

  11. An Evolving Trio of Hybrid Stars: C 111

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald (Technical Monitor); Dupree, Andrea K.

    2004-01-01

    Our goal is to understand the behavior of the outer atmosphere in this intermediate stage to create a comprehensive picture of atmospheric evolution. In the hybrid phase, the large-scale magnetic dynamo activity decays and hydrodynamic processes assume importance. Some hot plasma is still confined close to the star by magnetic loops, yet the confining field is breaking open, the atmosphere can escape through these open field lines, and the diffuse corona may be warm. There may well be a more extended and variable transition process. It remains for FUSE to identify the controlling parameters of the hybrid stars. It shows the positions of our 3 targets in the color-magnitude diagram where it is seen that they are at the extreme end of the hybrid region. Originally we had been awarded the hybrid star Iota Aur, but due to newly imposed pointing constraints of FUSE, that target was not accessible. And so we substituted Iota Dra, a giant of mass similar to our other targets but less evolved. In addition, Iota Dra was recently found to harbor a sub-stellar objects, possibly a planet, and so it could reveal the stellar environment of the planet. This substitution was accepted.

  12. Robustness and Evolvability of the Human Signaling Network

    PubMed Central

    Kim, Jeong-Rae; Munoz, Amaya Garcia; Kolch, Walter; Cho, Kwang-Hyun

    2014-01-01

    Biological systems are known to be both robust and evolvable to internal and external perturbations, but what causes these apparently contradictory properties? We used Boolean network modeling and attractor landscape analysis to investigate the evolvability and robustness of the human signaling network. Our results show that the human signaling network can be divided into an evolvable core where perturbations change the attractor landscape in state space, and a robust neighbor where perturbations have no effect on the attractor landscape. Using chemical inhibition and overexpression of nodes, we validated that perturbations affect the evolvable core more strongly than the robust neighbor. We also found that the evolvable core has a distinct network structure, which is enriched in feedback loops, and features a higher degree of scale-freeness and longer path lengths connecting the nodes. In addition, the genes with high evolvability scores are associated with evolvability-related properties such as rapid evolvability, low species broadness, and immunity whereas the genes with high robustness scores are associated with robustness-related properties such as slow evolvability, high species broadness, and oncogenes. Intriguingly, US Food and Drug Administration-approved drug targets have high evolvability scores whereas experimental drug targets have high robustness scores. PMID:25077791

  13. Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

    NASA Technical Reports Server (NTRS)

    Diaz, Carlos E., Jr.

    2015-01-01

    This paper provides a summary of the findings of recent activities conducted by Marshall Space Flight Center's (MSFC) In-Space Propulsion Branch and MSFC's Metrology and Calibration Lab to assess the performance of current "state of the art" pressure transducers for use in long duration storage and transfer of cryogenic propellants. A brief historical narrative in this paper describes the Evolvable Cryogenics program and the relevance of these activities to the program. This paper also provides a review of three separate test activities performed throughout this effort, including: (1) the calibration of several pressure transducer designs in a liquid nitrogen cryogenic environmental chamber, (2) the calibration of a pressure transducer in a liquid helium Dewar, and (3) the calibration of several pressure transducers at temperatures ranging from 20 to 70 degrees Kelvin (K) using a "cryostat" environmental chamber. These three separate test activities allowed for study of the sensors along a temperature range from 4 to 300 K. The combined data shows that both the slope and intercept of the sensor's calibration curve vary as a function of temperature. This homogeneous function is contrary to the linearly decreasing relationship assumed at the start of this investigation. Consequently, the data demonstrates the need for lookup tables to change the slope and intercept used by any data acquisition system. This ultimately would allow for more accurate pressure measurements at the desired temperature range. This paper concludes with a review of a request for information (RFI) survey conducted amongst different suppliers to determine the availability of current "state of the art" flight-qualified pressure transducers. The survey identifies requirements that are most difficult for the suppliers to meet, most notably the capability to validate the sensor's performance at temperatures below 70 K.

  14. Did DNA replication evolve twice independently?

    PubMed

    Leipe, D D; Aravind, L; Koonin, E V

    1999-09-01

    DNA replication is central to all extant cellular organisms. There are substantial functional similarities between the bacterial and the archaeal/eukaryotic replication machineries, including but not limited to defined origins, replication bidirectionality, RNA primers and leading and lagging strand synthesis. However, several core components of the bacterial replication machinery are unrelated or only distantly related to the functionally equivalent components of the archaeal/eukaryotic replication apparatus. This is in sharp contrast to the principal proteins involved in transcription and translation, which are highly conserved in all divisions of life. We performed detailed sequence comparisons of the proteins that fulfill indispensable functions in DNA replication and classified them into four main categories with respect to the conservation in bacteria and archaea/eukaryotes: (i) non-homologous, such as replicative polymerases and primases; (ii) containing homologous domains but apparently non-orthologous and conceivably independently recruited to function in replication, such as the principal replicative helicases or proofreading exonucleases; (iii) apparently orthologous but poorly conserved, such as the sliding clamp proteins or DNA ligases; (iv) orthologous and highly conserved, such as clamp-loader ATPases or 5'-->3' exonucleases (FLAP nucleases). The universal conservation of some components of the DNA replication machinery and enzymes for DNA precursor biosynthesis but not the principal DNA polymerases suggests that the last common ancestor (LCA) of all modern cellular life forms possessed DNA but did not replicate it the way extant cells do. We propose that the LCA had a genetic system that contained both RNA and DNA, with the latter being produced by reverse transcription. Consequently, the modern-type system for double-stranded DNA replication likely evolved independently in the bacterial and archaeal/eukaryotic lineages.

  15. A possible molecular metric for biological evolvability.

    PubMed

    Mittal, Aditya; Jayaram, B

    2012-07-01

    Proteins manifest themselves as phenotypic traits, retained or lost in living systems via evolutionary pressures. Simply put, survival is essentially the ability of a living system to synthesize a functional protein that allows for a response to environmental perturbations (adaptation). Loss of functional proteins leads to extinction. Currently there are no universally applicable quantitative metrics at the molecular level for either measuring 'evolvability' of life or for assessing the conditions under which a living system would go extinct and why. In this work, we show emergence of the first such metric by utilizing the recently discovered stoichiometric margin of life for all known naturally occurring (and functional) proteins. The constraint of having well-defined stoichiometries of the 20 amino acids in naturally occurring protein sequences requires utilization of the full scope of degeneracy in the genetic code, i.e. usage of all codons coding for an amino acid, by only 11 of the 20 amino acids. This shows that the non-availability of individual codons for these 11 amino acids would disturb the fine stoichiometric balance resulting in non-functional proteins and hence extinction. Remarkably, these amino acids are found in close proximity of any given amino acid in the backbones of thousands of known crystal structures of folded proteins. On the other hand, stoichiometry of the remaining 9 amino acids, found to be farther/distal from any given amino acid in backbones of folded proteins, is maintained independent of the number of codons available to synthesize them, thereby providing some robustness and hence survivability.

  16. Evolving Recommendations on Prostate Cancer Screening.

    PubMed

    Brawley, Otis W; Thompson, Ian M; Grönberg, Henrik

    2016-01-01

    Results of a number of studies demonstrate that the serum prostate-specific antigen (PSA) in and of itself is an inadequate screening test. Today, one of the most pressing questions in prostate cancer medicine is how can screening be honed to identify those who have life-threatening disease and need aggressive treatment. A number of efforts are underway. One such effort is the assessment of men in the landmark Prostate Cancer Prevention Trial that has led to a prostate cancer risk calculator (PCPTRC), which is available online. PCPTRC version 2.0 predicts the probability of the diagnosis of no cancer, low-grade cancer, or high-grade cancer when variables such as PSA, age, race, family history, and physical findings are input. Modern biomarker development promises to provide tests with fewer false positives and improved ability to find high-grade cancers. Stockholm III (STHLM3) is a prospective, population-based, paired, screen-positive, prostate cancer diagnostic study assessing a combination of plasma protein biomarkers along with age, family history, previous biopsy, and prostate examination for prediction of prostate cancer. Multiparametric MRI incorporates anatomic and functional imaging to better characterize and predict future behavior of tumors within the prostate. After diagnosis of cancer, several genomic tests promise to better distinguish the cancers that need treatment versus those that need observation. Although the new technologies are promising, there is an urgent need for evaluation of these new tests in high-quality, large population-based studies. Until these technologies are proven, most professional organizations have evolved to a recommendation of informed or shared decision making in which there is a discussion between the doctor and patient. PMID:27249774

  17. Evolving detectors of 2D patterns on a simulated CAM-Brain machine: an evolvable hardware tool for building a 75-million-neuron artificial brain

    NASA Astrophysics Data System (ADS)

    de Garis, Hugo; Korkin, Michael; Guttikonda, Padma; Cooley, Donald

    2000-11-01

    This paper presents some simulation results of the evolution of 2D visual pattern recognizers to be implemented very shortly on real hardware, namely the 'CAM-Brain Machine' (CBM), an FPGA based piece of evolvable hardware which implements a genetic algorithm (GA) to evolve a 3D cellular automata (CA) based neural network circuit module, of approximately 1,000 neurons, in about a second, i.e. a complete run of a GA, with 10,000s of circuit growths and performance evaluations. Up to 65,000 of these modules, each of which is evolved with a humanly specified function, can be downloaded into a large RAM space, and interconnected according to humanly specified gvdvips -o SPIE-2000.ps SPIE-2000 artificial brain architectures. This RAM, containing an artificial brain with up to 75 million neurons, is then updated by the CBM at a rate of 130 billion CA cells per second. Such speeds will enable real time control of robots and hopefully the birth of a new research field that we call 'brain building.' The first such artificial brain, to be built at STARLAB in 2000 and beyond, will be used to control the behaviors of a life sized kitten robot called 'Robokitty.' This kitten robot will need 2D pattern recognizers in the visual section of its artificial brain. This paper presents simulation results on the evolvability and generalization properties of such recognizers.

  18. Conceptualizing Evolving Models of Educational Development

    ERIC Educational Resources Information Center

    Fraser, Kym; Gosling, David; Sorcinelli, Mary Deane

    2010-01-01

    Educational development, which the authors use to refer to the field of professional and strategic development associated with university and college learning and teaching, can be described in many ways by referring to its different aspects. In this article the authors endeavor to categorize many of the models that have been used to describe…

  19. Cancer and aging. An evolving panorama.

    PubMed

    Balducci, L; Extermann, M

    2000-02-01

    This article illustrates how the nosology of cancer evolves with the patient's age. If the current trends are maintained, 70% of all neoplasms will occur in persons aged 65 years and over by the year 2020, leading to increased cancer-related morbidity among older persons. Cancer control in the older person involves chemoprevention, early diagnosis, and timely and effective treatment that entails both antineoplastic therapy and symptom management. These interventions must be individualized based on a multidimensional assessment that can predict life expectancy and treatment complications and that may evaluate the quality of life of the older person. This article suggests a number of interventions that may improve cancer control in the aged. Public education is needed to illustrate the benefits of health maintenance and early detection of cancer even among older individuals, to create realistic expectations, and to heighten awareness of early symptoms and signs of cancer. Professional education is needed to train students and practitioners in the evaluation and management of the older person. Of special interest is the current initiative of the Hartford Foundation offering combined fellowships in oncology and geriatrics and incorporating principles of geriatric medicine in medical specialty training. Prudent pharmacologic principles must be followed in managing older persons with cytotoxic chemotherapy. These principles include adjusting the dose according to the patient's renal function, using epoietin to maintain hemoglobin levels of 12 g/dL or more, and using hemopoietic growth factors in persons aged 70 years and older receiving cytotoxic chemotherapy of moderate toxicity (e.g., CHOP). To assure uniformity of data, a cooperative oncology group should formulate a geriatric package outlining a common plan for evaluating function and comorbidity. This article also suggests several important areas of research items: Molecular interactions of age and cancer Host

  20. Observational studies of highly evolved cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Uthas, Helena

    2011-05-01

    According to standard evolutionary theory for cataclysmic variables (CVs), angular momentum loss drives CVs to initially evolve from longer to shorter orbital periods until a minimum period is reached (approx 80 min). At roughly this stage, the donors becomes degenerate, expand in size, and the systems move towards longer Porb. Theory predicts that 70% of all CVs should have passed their minimum period and have sub-stellar donors, but until recently, no such systems were known. I present one CV showing evidence of harbouring a sub-dwarf donor, SDSS J1507+52. Due to the system's unusually short Porb of about 65 min, and very high space velocity, two origins for SDSS J1507+52 have been proposed; either the system was formed from a young WD/brown-dwarf binary, or the system is a halo CV. In order to distinguish between these two theories, I present UV spectroscopy and find a metallicity consistent with halo origin. Systems close to Pmin are expected to have low accretion rates. Some of these CVs show absorption in their spectra, implying that the underlying WD is exposed. This yields a rare opportunity to study the WD in a CV. I introduce two new systems showing WD signatures in their light curves and spectra, SDSS J1457+51 and BW Scl. Despite the fact that CVs close to Pmin should be faint, we find systems that are much too bright for their Porb. Such a system is T Pyx - a recurrent nova with an unusually high accretion rate and a photometrically determined Porb < 2 hr. T Pyx is about 2 times brighter than any other CV at its period. However, to confirm its evolutionary status, a more reliable period determination is needed. Here, I present a spectroscopic study, confirming T Pyx as a short-period CV. In this thesis, I discuss what implications these systems may have on the current understanding of CV evolution, and the importance of studying individual systems in general.

  1. The Evolvement of Automobile Steering System Based on TRIZ

    NASA Astrophysics Data System (ADS)

    Zhao, Xinjun; Zhang, Shuang

    Products and techniques pass through a process of birth, growth, maturity, death and quit the stage like biological evolution process. The developments of products and techniques conform to some evolvement rules. If people know and hold these rules, they can design new kind of products and forecast the develop trends of the products. Thereby, enterprises can grasp the future technique directions of products, and make product and technique innovation. Below, based on TRIZ theory, the mechanism evolvement, the function evolvement and the appearance evolvement of automobile steering system had been analyzed and put forward some new ideas about future automobile steering system.

  2. AKI and Genetics: Evolving Concepts in the Genetics of Acute Kidney Injury: Implications for Pediatric AKI.

    PubMed

    Lee-Son, Kathy; Jetton, Jennifer G

    2016-03-01

    In spite of recent advances in the field of acute kidney injury (AKI) research, morbidity and mortality remain high for AKI sufferers. The study of genetic influences in AKI pathways is an evolving field with potential for improving outcomes through the identification of risk and protective factors at the individual level that may in turn allow for the development of rational therapeutic interventions. Studies of single nucleotide polymorphisms, individual susceptibility to nephrotoxic medications, and epigenetic factors comprise a growing body of research in this area. While promising, this field is still only emerging, with a small number of studies in humans and very little data in pediatric patients. PMID:27617143

  3. Can Venus magnetosheath plasma evolve into turbulence?

    NASA Astrophysics Data System (ADS)

    Dwivedi, Navin; Schmid, Daniel; Narita, Yasuhito; Volwerk, Martin; Delva, Magda; Voros, Zoltan; Zhang, Tielong

    2014-05-01

    The present work aims to understand turbulence properties in planetary magnetosheath regions to obtain physical insight on the energy transfer from the larger to smaller scales, in spirit of searching for power-law behaviors in the spectra which is an indication of the energy cascade and wave-wave interaction. We perform a statistical analysis of energy spectra using the Venus Express spacecraft data in the Venusian magnetosheath. The fluxgate magnetometer data (VEXMAG) calibrated down to 1 Hz as well as plasma data from the ion mass analyzer (ASPERA) aboard the spacecraft are used in the years 2006-2009. Ten-minute intervals in the magnetosheath are selected, which is typical time length of observations of quasi-stationary fluctuations avoiding multiple boundaries crossings. The magnetic field data are transformed into the mean-field-aligned (MFA) coordinate system with respect to the large-scale magnetic field direction and the energy spectra are evaluated using a Welch algorithm in the frequency range between 0.008 Hz and 0.5 Hz for 105 time intervals. The averaged energy spectra show a power law upto 0.3 Hz with the approximate slope of -1, which is flatter than the Kolmogorov slope, -5/3. A slight hump in the spectra is found in the compressive component near 0.3 Hz, which could possibly be realization of mirror mode in the magnetosheath. A spectral break (sudden change in slope) accompanies the spectral hump at 0.4 Hz, above which the spectral curve becomes steeper. The overall spectral shape is reminiscent of turbulence. The low-frequency part with the slope -1 is interpreted as realization of the energy containing range, while the high-frequency part with the steepening is interpreted either as the beginning of energy cascade mediated by mirror mode or as the dissipation range due to wave-particle resonance processes. The present research work is fully supported by FP7/STORM (313038).

  4. Health-Literate Youth: Evolving Challenges for Health Educators

    ERIC Educational Resources Information Center

    Fetro, Joyce V.

    2010-01-01

    This article presents the author's AAHE Scholar presentation at the 2010 AAHE annual meeting in Indianapolis, Indiana. In her discussion, the author addresses what she sees to be some evolving challenges for health educators working with youth as well as some possible strategies for addressing them. These evolving challenges are: (1) understanding…

  5. Adaptation of Escherichia coli to glucose promotes evolvability in lactose.

    PubMed

    Phillips, Kelly N; Castillo, Gerardo; Wünsche, Andrea; Cooper, Tim F

    2016-02-01

    The selective history of a population can influence its subsequent evolution, an effect known as historical contingency. We previously observed that five of six replicate populations that were evolved in a glucose-limited environment for 2000 generations, then switched to lactose for 1000 generations, had higher fitness increases in lactose than populations started directly from the ancestor. To test if selection in glucose systematically increased lactose evolvability, we started 12 replay populations--six from a population subsample and six from a single randomly selected clone--from each of the six glucose-evolved founder populations. These replay populations and 18 ancestral populations were evolved for 1000 generations in a lactose-limited environment. We found that replay populations were initially slightly less fit in lactose than the ancestor, but were more evolvable, in that they increased in fitness at a faster rate and to higher levels. This result indicates that evolution in the glucose environment resulted in genetic changes that increased the potential of genotypes to adapt to lactose. Genome sequencing identified four genes--iclR, nadR, spoT, and rbs--that were mutated in most glucose-evolved clones and are candidates for mediating increased evolvability. Our results demonstrate that short-term selective costs during selection in one environment can lead to changes in evolvability that confer longer term benefits. PMID:26748670

  6. Loops and autonomy promote evolvability of ecosystem networks.

    PubMed

    Luo, Jianxi

    2014-01-01

    The structure of ecological networks, in particular food webs, determines their ability to evolve further, i.e. evolvability. The knowledge about how food web evolvability is determined by the structures of diverse ecological networks can guide human interventions purposefully to either promote or limit evolvability of ecosystems. However, the focus of prior food web studies was on stability and robustness; little is known regarding the impact of ecological network structures on their evolvability. To correlate ecosystem structure and evolvability, we adopt the NK model originally from evolutionary biology to generate and assess the ruggedness of fitness landscapes of a wide spectrum of model food webs with gradual variation in the amount of feeding loops and link density. The variation in network structures is controlled by linkage rewiring. Our results show that more feeding loops and lower trophic link density, i.e. higher autonomy of species, of food webs increase the potential for the ecosystem to generate heritable variations with improved fitness. Our findings allow the prediction of the evolvability of actual food webs according to their network structures, and provide guidance to enhancing or controlling the evolvability of specific ecosystems.

  7. Quantifying dynamical spillover in co-evolving multiplex networks

    NASA Astrophysics Data System (ADS)

    Vijayaraghavan, Vikram S.; Noël, Pierre-André; Maoz, Zeev; D'Souza, Raissa M.

    2015-10-01

    Multiplex networks (a system of multiple networks that have different types of links but share a common set of nodes) arise naturally in a wide spectrum of fields. Theoretical studies show that in such multiplex networks, correlated edge dynamics between the layers can have a profound effect on dynamical processes. However, how to extract the correlations from real-world systems is an outstanding challenge. Here we introduce the Multiplex Markov chain to quantify correlations in edge dynamics found in longitudinal data of multiplex networks. By comparing the results obtained from the multiplex perspective to a null model which assumes layers in a network are independent, we can identify real correlations as distinct from simultaneous changes that occur due to random chance. We use this approach on two different data sets: the network of trade and alliances between nation states, and the email and co-commit networks between developers of open source software. We establish the existence of “dynamical spillover” showing the correlated formation (or deletion) of edges of different types as the system evolves. The details of the dynamics over time provide insight into potential causal pathways.

  8. Evolving Insights on Metabolism, Autophagy, and Epigenetics in Liver Myofibroblasts

    PubMed Central

    Nwosu, Zeribe C.; Alborzinia, Hamed; Wölfl, Stefan; Dooley, Steven; Liu, Yan

    2016-01-01

    Liver myofibroblasts (MFB) are crucial mediators of extracellular matrix (ECM) deposition in liver fibrosis. They arise mainly from hepatic stellate cells (HSCs) upon a process termed “activation.” To a lesser extent, and depending on the cause of liver damage, portal fibroblasts, mesothelial cells, and fibrocytes may also contribute to the MFB population. Targeting MFB to reduce liver fibrosis is currently an area of intense research. Unfortunately, a clog in the wheel of antifibrotic therapies is the fact that although MFB are known to mediate scar formation, and participate in liver inflammatory response, many of their molecular portraits are currently unknown. In this review, we discuss recent understanding of MFB in health and diseases, focusing specifically on three evolving research fields: metabolism, autophagy, and epigenetics. We have emphasized on therapeutic prospects where applicable and mentioned techniques for use in MFB studies. Subsequently, we highlighted uncharted territories in MFB research to help direct future efforts aimed at bridging gaps in current knowledge. PMID:27313533

  9. Quantifying dynamical spillover in co-evolving multiplex networks

    PubMed Central

    Vijayaraghavan, Vikram S.; Noël, Pierre-André; Maoz, Zeev; D’Souza, Raissa M.

    2015-01-01

    Multiplex networks (a system of multiple networks that have different types of links but share a common set of nodes) arise naturally in a wide spectrum of fields. Theoretical studies show that in such multiplex networks, correlated edge dynamics between the layers can have a profound effect on dynamical processes. However, how to extract the correlations from real-world systems is an outstanding challenge. Here we introduce the Multiplex Markov chain to quantify correlations in edge dynamics found in longitudinal data of multiplex networks. By comparing the results obtained from the multiplex perspective to a null model which assumes layers in a network are independent, we can identify real correlations as distinct from simultaneous changes that occur due to random chance. We use this approach on two different data sets: the network of trade and alliances between nation states, and the email and co-commit networks between developers of open source software. We establish the existence of “dynamical spillover” showing the correlated formation (or deletion) of edges of different types as the system evolves. The details of the dynamics over time provide insight into potential causal pathways. PMID:26459949

  10. Compact configurations within small evolving groups of galaxies

    NASA Astrophysics Data System (ADS)

    Mamon, G. A.

    Small virialized groups of galaxies are evolved with a gravitational N-body code, where the galaxies and a diffuse background are treated as single particles, but with mass and luminosity profiles attached, which enbles the estimation of parameters such as internal energies, half-mass radii, and the softened potential energies of interaction. The numerical treatment includes mergers, collisional stripping, tidal limitation by the mean-field of the background (evaluated using a combination of instantaneous and impulsive formulations), galaxy heating from collisons, and background heating from dynamical friction. The groups start out either as dense as appear the groups in Hickson's (1982) catalog, or as loose as appear those in Turner and Gott's (1976a) catalog, and they are simulated many times (usually 20) with different initial positions and velocities. Dense groups of galaxies with massive dark haloes coalesce into a single galaxy and lose their compact group appearance in approximately 3 group half-mass crossing times, while dense groups of galaxies without massive haloes survive the merger instability for 15 half-mass crossing times (in a more massive background to keep the same total group mass).

  11. Laplacian Estrada and normalized Laplacian Estrada indices of evolving graphs.

    PubMed

    Shang, Yilun

    2015-01-01

    Large-scale time-evolving networks have been generated by many natural and technological applications, posing challenges for computation and modeling. Thus, it is of theoretical and practical significance to probe mathematical tools tailored for evolving networks. In this paper, on top of the dynamic Estrada index, we study the dynamic Laplacian Estrada index and the dynamic normalized Laplacian Estrada index of evolving graphs. Using linear algebra techniques, we established general upper and lower bounds for these graph-spectrum-based invariants through a couple of intuitive graph-theoretic measures, including the number of vertices or edges. Synthetic random evolving small-world networks are employed to show the relevance of the proposed dynamic Estrada indices. It is found that neither the static snapshot graphs nor the aggregated graph can approximate the evolving graph itself, indicating the fundamental difference between the static and dynamic Estrada indices. PMID:25822506

  12. Gene Essentiality Is a Quantitative Property Linked to Cellular Evolvability.

    PubMed

    Liu, Gaowen; Yong, Mei Yun Jacy; Yurieva, Marina; Srinivasan, Kandhadayar Gopalan; Liu, Jaron; Lim, John Soon Yew; Poidinger, Michael; Wright, Graham Daniel; Zolezzi, Francesca; Choi, Hyungwon; Pavelka, Norman; Rancati, Giulia

    2015-12-01

    Gene essentiality is typically determined by assessing the viability of the corresponding mutant cells, but this definition fails to account for the ability of cells to adaptively evolve to genetic perturbations. Here, we performed a stringent screen to assess the degree to which Saccharomyces cerevisiae cells can survive the deletion of ~1,000 individual "essential" genes and found that ~9% of these genetic perturbations could in fact be overcome by adaptive evolution. Our analyses uncovered a genome-wide gradient of gene essentiality, with certain essential cellular functions being more "evolvable" than others. Ploidy changes were prevalent among the evolved mutant strains, and aneuploidy of a specific chromosome was adaptive for a class of evolvable nucleoporin mutants. These data justify a quantitative redefinition of gene essentiality that incorporates both viability and evolvability of the corresponding mutant cells and will enable selection of therapeutic targets associated with lower risk of emergence of drug resistance. PMID:26627736

  13. Gene Essentiality Is a Quantitative Property Linked to Cellular Evolvability.

    PubMed

    Liu, Gaowen; Yong, Mei Yun Jacy; Yurieva, Marina; Srinivasan, Kandhadayar Gopalan; Liu, Jaron; Lim, John Soon Yew; Poidinger, Michael; Wright, Graham Daniel; Zolezzi, Francesca; Choi, Hyungwon; Pavelka, Norman; Rancati, Giulia

    2015-12-01

    Gene essentiality is typically determined by assessing the viability of the corresponding mutant cells, but this definition fails to account for the ability of cells to adaptively evolve to genetic perturbations. Here, we performed a stringent screen to assess the degree to which Saccharomyces cerevisiae cells can survive the deletion of ~1,000 individual "essential" genes and found that ~9% of these genetic perturbations could in fact be overcome by adaptive evolution. Our analyses uncovered a genome-wide gradient of gene essentiality, with certain essential cellular functions being more "evolvable" than others. Ploidy changes were prevalent among the evolved mutant strains, and aneuploidy of a specific chromosome was adaptive for a class of evolvable nucleoporin mutants. These data justify a quantitative redefinition of gene essentiality that incorporates both viability and evolvability of the corresponding mutant cells and will enable selection of therapeutic targets associated with lower risk of emergence of drug resistance.

  14. Laplacian Estrada and normalized Laplacian Estrada indices of evolving graphs.

    PubMed

    Shang, Yilun

    2015-01-01

    Large-scale time-evolving networks have been generated by many natural and technological applications, posing challenges for computation and modeling. Thus, it is of theoretical and practical significance to probe mathematical tools tailored for evolving networks. In this paper, on top of the dynamic Estrada index, we study the dynamic Laplacian Estrada index and the dynamic normalized Laplacian Estrada index of evolving graphs. Using linear algebra techniques, we established general upper and lower bounds for these graph-spectrum-based invariants through a couple of intuitive graph-theoretic measures, including the number of vertices or edges. Synthetic random evolving small-world networks are employed to show the relevance of the proposed dynamic Estrada indices. It is found that neither the static snapshot graphs nor the aggregated graph can approximate the evolving graph itself, indicating the fundamental difference between the static and dynamic Estrada indices.

  15. Food Addiction: An Evolving Nonlinear Science

    PubMed Central

    Shriner, Richard; Gold, Mark

    2014-01-01

    The purpose of this review is to familiarize readers with the role that addiction plays in the formation and treatment of obesity, type 2 diabetes and disorders of eating. We will outline several useful models that integrate metabolism, addiction, and human relationship adaptations to eating. A special effort will be made to demonstrate how the use of simple and straightforward nonlinear models can and are being used to improve our knowledge and treatment of patients suffering from nutritional pathology. Moving forward, the reader should be able to incorporate some of the findings in this review into their own practice, research, teaching efforts or other interests in the fields of nutrition, diabetes, and/or bariatric (weight) management. PMID:25421535

  16. A SEARCH FOR CO-EVOLVING ION AND NEUTRAL GAS SPECIES IN PRESTELLAR MOLECULAR CLOUD CORES

    SciTech Connect

    Tassis, Konstantinos; Hezareh, Talayeh; Willacy, Karen

    2012-11-20

    A comparison between the widths of ion and neutral molecule spectral lines has been recently used to estimate the strength of the magnetic field in turbulent star-forming regions. However, the ion (HCO{sup +}) and neutral (HCN) species used in such studies may not be necessarily co-evolving at every scale and density, and thus, may not trace the same regions. Here, we use coupled chemical/dynamical models of evolving prestellar molecular cloud cores including non-equilibrium chemistry, with and without magnetic fields, to study the spatial distribution of HCO{sup +} and HCN, which have been used in observations of spectral line width differences to date. In addition, we seek new ion-neutral pairs that are good candidates for such observations, because they have similar evolution and are approximately co-spatial in our models. We identify three such good candidate pairs: HCO{sup +}/NO, HCO{sup +}/CO, and NO{sup +}/NO.

  17. Chromospheric activity of evolved late-type stars - Chromospheric activity in evolved stars

    NASA Astrophysics Data System (ADS)

    Pasquini, L.; Brocato, E.; Pallavicini, R.

    1990-08-01

    Ca II K emission in a homogeneous sample of late-type giants and supergiants is analyzed. The Wilson-Bappu relationship and color-temperature scales are used to construct an H-R diagram which is compared with theoretical evolutionary tracks. It is shown that in spite of the errors involved in the determination of the fundamental stellar parameters, a clear relationship between chromospheric surface activity and stellar mass is present. 5-10 solar mass stars in He burning phase show the highest levels of activity; on the other hand, less massive stars ascending along the Red Giant Branch are extremely quiet. A correlation between surface activity and rotation is found, and it is shown that a knowledge of the stellar evolutionary history is essential for understanding chromospheric emission from evolved stars.

  18. NASA's Space Launch System: An Evolving Capability for Exploration An Evolving Capability for Exploration

    NASA Technical Reports Server (NTRS)

    Creech, Stephen D.; Crumbly, Christopher M.; Robinson, Kimerly F.

    2016-01-01

    A foundational capability for international human deep-space exploration, NASA's Space Launch System (SLS) vehicle represents a new spaceflight infrastructure asset, creating opportunities for mission profiles and space systems that cannot currently be executed. While the primary purpose of SLS, which is making rapid progress towards initial launch readiness in two years, will be to support NASA's Journey to Mars, discussions are already well underway regarding other potential utilization of the vehicle's unique capabilities. In its initial Block 1 configuration, capable of launching 70 metric tons (t) to low Earth orbit (LEO), SLS is capable of propelling the Orion crew vehicle to cislunar space, while also delivering small CubeSat-class spacecraft to deep-space destinations. With the addition of a more powerful upper stage, the Block 1B configuration of SLS will be able to deliver 105 t to LEO and enable more ambitious human missions into the proving ground of space. This configuration offers opportunities for launching co-manifested payloads with the Orion crew vehicle, and a class of secondary payloads, larger than today's CubeSats. Further upgrades to the vehicle, including advanced boosters, will evolve its performance to 130 t in its Block 2 configuration. Both Block 1B and Block 2 also offer the capability to carry 8.4- or 10-m payload fairings, larger than any contemporary launch vehicle. With unmatched mass-lift capability, payload volume, and C3, SLS not only enables spacecraft or mission designs currently impossible with contemporary EELVs, it also offers enhancing benefits, such as reduced risk, operational costs and/or complexity, shorter transit time to destination or launching large systems either monolithically or in fewer components. This paper will discuss both the performance and capabilities of Space Launch System as it evolves, and the current state of SLS utilization planning.

  19. A fibre based triature interferometer for measuring rapidly evolving, ablatively driven plasma densities

    NASA Astrophysics Data System (ADS)

    Macdonald, J.; Bland, S. N.; Threadgold, J.

    2015-08-01

    We report on the first use of a fibre interferometer incorporating triature analysis for measuring rapidly evolving plasma densities of ne ˜ 1013/cm3 and above, such as those produced by simple coaxial plasma guns. The resultant system is extremely portable, easy to field in experiments, relatively cheap to produce, and—with the exception of a small open area in which the plasma is sampled—safe in operation as all laser light is enclosed.

  20. The role of the physician-scientist in our evolving society.

    PubMed

    Rosen, Michael R

    2011-10-01

    The physician-scientist represents the medical-scientific version of the "triple threat" athlete. Yet, in medicine as in sports, specialization and business are ever more in the forefront. As the field of medicine evolves, it is likely that the role of the physician, the scientist, and the physician-scientist will continue to change. Whether this is for the good or bad will only be known in hindsight.

  1. Senescence and cancer: An evolving inflammatory paradox.

    PubMed

    Ruhland, Megan K; Coussens, Lisa M; Stewart, Sheila A

    2016-01-01

    The senescent phenotype was first described in 1961 as a phenomenon characterized by the cessation of cellular division. After years of debate as to whether it represented a tissue culture artifact or an important biological process, it is now appreciated that senescence plays an important role in tumorigenesis. Further, senescence is integral to normal biological processes such as embryogenesis and the maintenance of tissue homeostasis. Now with defined roles in development, wound healing, tumor promotion and tumor suppression, it is not surprising that attention has turned to refining our understanding of the mechanisms behind, and consequences of, the induction of senescence. One emerging role for senescence lies in the ability of senescence to orchestrate an inflammatory response: factors secreted by senescent cells have been identified in multiple contexts to modulate various aspects of the immune response. As with many of the previously described roles for senescence, the type of inflammation established by the senescence phenotype is varied and dependent on context. In this review, we discuss the current state of the field with a focus on the paradoxical outcomes of the senescence-induced inflammatory responses in the context of cancer. A more complete understanding of senescence and an appreciation for its complexities will be important for eventual development of senescence-targeted therapies. PMID:26453912

  2. Grounding explanations in evolving, diagnostic situations

    NASA Technical Reports Server (NTRS)

    Johannesen, Leila J.; Cook, Richard I.; Woods, David D.

    1994-01-01

    Certain fields of practice involve the management and control of complex dynamic systems. These include flight deck operations in commercial aviation, control of space systems, anesthetic management during surgery or chemical or nuclear process control. Fault diagnosis of these dynamic systems generally must occur with the monitored process on-line and in conjunction with maintaining system integrity.This research seeks to understand in more detail what it means for an intelligent system to function cooperatively, or as a 'team player' in complex, dynamic environments. The approach taken was to study human practitioners engaged in the management of a complex, dynamic process: anesthesiologists during neurosurgical operations. The investigation focused on understanding how team members cooperate in management and fault diagnosis and comparing this interaction to the situation with an Artificial Intelligence(AI) system that provides diagnoses and explanations. Of particular concern was to study the ways in which practitioners support one another in keeping aware of relevant information concerning the state of the monitored process and of the problem solving process.

  3. Advances in understanding erythropoiesis: evolving perspectives.

    PubMed

    Nandakumar, Satish K; Ulirsch, Jacob C; Sankaran, Vijay G

    2016-04-01

    Red blood cells (RBCs) are generated from haematopoietic stem and progenitor cells (HSPCs) through the step-wise process of differentiation known as erythropoiesis. In this review, we discuss our current understanding of erythropoiesis and highlight recent advances in this field. During embryonic development, erythropoiesis occurs in three distinct waves comprising first, the yolk sac-derived primitive RBCs, followed sequentially by the erythro-myeloid progenitor (EMP) and HSPC-derived definitive RBCs. Recent work has highlighted the complexity and variability that may exist in the hierarchical arrangement of progenitors responsible for erythropoiesis. Using recently defined cell surface markers, it is now possible to enrich for erythroid progenitors and precursors to a much greater extent than has been possible before. While a great deal of knowledge has been gained on erythropoiesis from model organisms, our understanding of this process is currently being refined through human genetic studies. Genes mutated in erythroid disorders can now be identified more rapidly by the use of next-generation sequencing techniques. Genome-wide association studies on erythroid traits in healthy populations have also revealed new modulators of erythropoiesis. All of these recent developments have significant promise not only for increasing our understanding of erythropoiesis, but also for improving our ability to intervene when RBC production is perturbed in disease. PMID:26846448

  4. Multiscale macromolecular simulation: role of evolving ensembles.

    PubMed

    Singharoy, A; Joshi, H; Ortoleva, P J

    2012-10-22

    Multiscale analysis provides an algorithm for the efficient simulation of macromolecular assemblies. This algorithm involves the coevolution of a quasiequilibrium probability density of atomic configurations and the Langevin dynamics of spatial coarse-grained variables denoted order parameters (OPs) characterizing nanoscale system features. In practice, implementation of the probability density involves the generation of constant OP ensembles of atomic configurations. Such ensembles are used to construct thermal forces and diffusion factors that mediate the stochastic OP dynamics. Generation of all-atom ensembles at every Langevin time step is computationally expensive. Here, multiscale computation for macromolecular systems is made more efficient by a method that self-consistently folds in ensembles of all-atom configurations constructed in an earlier step, history, of the Langevin evolution. This procedure accounts for the temporal evolution of these ensembles, accurately providing thermal forces and diffusions. It is shown that efficiency and accuracy of the OP-based simulations is increased via the integration of this historical information. Accuracy improves with the square root of the number of historical timesteps included in the calculation. As a result, CPU usage can be decreased by a factor of 3-8 without loss of accuracy. The algorithm is implemented into our existing force-field based multiscale simulation platform and demonstrated via the structural dynamics of viral capsomers.

  5. EVOLVE historical and projected orbital debris test environments

    NASA Astrophysics Data System (ADS)

    Krisko, P. H.

    2004-01-01

    The NASA/JSC orbital debris research effort within the Earth's low-altitude regime continues with the upgrade of the debris environment simulation model EVOLVE. Two main contributions to this new version will include a more streamlined structure (transparent to the analyst) and an updated, expanded set of launch/orbital insertion files. The new database includes such improvements as high fidelity launch times and orbital elements, dataderived area-to-mass ratios, and individual object dry mass and physical description. As an additional test of the new code, a version of the Anz-Meador [Adv. Space Res. (2004)] explosive fragmentation model is implemented and the resulting historical and projected LEO environments are compared to those of the US Space Surveillance Network (SSN) Catalog, ORDEM2000, and EVOLVE 4.1 (the current production version of the code) historical and projection periods EVOLVE test historical environments compare well with the catalog and ORDEM2000 environments over the 1-mm and larger size range. However, it should be noted that SRM slag is not included in EVOLVE at this time. Differences between the EVOLVE test and the EVOLVE 4.1 long-term projection environments are traced directly to the modified launch cycle and the chosen form of the Anz-Meador [Adv. Space Res. (2004)] breakup model of this EVOLVE test.

  6. Mixtures research at NIEHS: an evolving program.

    PubMed

    Rider, Cynthia V; Carlin, Danielle J; Devito, Micheal J; Thompson, Claudia L; Walker, Nigel J

    2013-11-16

    The National Institute of Environmental Health Sciences (NIEHS) has a rich history in evaluating the toxicity of mixtures. The types of mixtures assessed by the Division of the National Toxicology Program (DNTP) and the extramural community (through the Division of Extramural Research and Training, DERT) have included a broad range of chemicals and toxicants, with each study having a unique set of questions and design considerations. Some examples of the types of mixtures studied include: groundwater contaminants, pesticides/fertilizers, dioxin-like chemicals (assessing the toxic equivalency approach), drug combinations, air pollution, metals, polycyclic aromatic hydrocarbons, technical mixtures (e.g., pentachlorophenol, flame retardants), and mixed entities (e.g., herbals, asbestos). These endeavors have provided excellent data on the toxicity of specific mixtures and have been informative to the human health risk assessment process in general (e.g., providing data on low dose exposures to environmental chemicals). However, the mixtures research effort at NIEHS, to date, has been driven by test article nominations to the DNTP or by investigator-initiated research through DERT. Recently, the NIEHS has embarked upon an effort to coordinate mixtures research across both intramural and extramural divisions in order to maximize mixtures research results. A path forward for NIEHS mixtures research will be based on feedback from a Request for Information (RFI) designed to gather up-to-date views on the knowledge gaps and roadblocks to evaluating mixtures and performing cumulative risk assessment, and a workshop organized to bring together mixtures experts from risk assessment, exposure science, biology, epidemiology, and statistics. The future of mixtures research at NIEHS will include projects from nominations to DNTP, studies by extramural investigators, and collaborations across government agencies that address high-priority questions in the field of mixtures research

  7. Mixtures research at NIEHS: an evolving program.

    PubMed

    Rider, Cynthia V; Carlin, Danielle J; Devito, Micheal J; Thompson, Claudia L; Walker, Nigel J

    2013-11-16

    The National Institute of Environmental Health Sciences (NIEHS) has a rich history in evaluating the toxicity of mixtures. The types of mixtures assessed by the Division of the National Toxicology Program (DNTP) and the extramural community (through the Division of Extramural Research and Training, DERT) have included a broad range of chemicals and toxicants, with each study having a unique set of questions and design considerations. Some examples of the types of mixtures studied include: groundwater contaminants, pesticides/fertilizers, dioxin-like chemicals (assessing the toxic equivalency approach), drug combinations, air pollution, metals, polycyclic aromatic hydrocarbons, technical mixtures (e.g., pentachlorophenol, flame retardants), and mixed entities (e.g., herbals, asbestos). These endeavors have provided excellent data on the toxicity of specific mixtures and have been informative to the human health risk assessment process in general (e.g., providing data on low dose exposures to environmental chemicals). However, the mixtures research effort at NIEHS, to date, has been driven by test article nominations to the DNTP or by investigator-initiated research through DERT. Recently, the NIEHS has embarked upon an effort to coordinate mixtures research across both intramural and extramural divisions in order to maximize mixtures research results. A path forward for NIEHS mixtures research will be based on feedback from a Request for Information (RFI) designed to gather up-to-date views on the knowledge gaps and roadblocks to evaluating mixtures and performing cumulative risk assessment, and a workshop organized to bring together mixtures experts from risk assessment, exposure science, biology, epidemiology, and statistics. The future of mixtures research at NIEHS will include projects from nominations to DNTP, studies by extramural investigators, and collaborations across government agencies that address high-priority questions in the field of mixtures research.

  8. 21 CFR 520.2130 - Spinosad.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... weight. (ii) Indications for use. To kill fleas and for the prevention and treatment of flea infestations... mg per kilogram) of body weight. (ii) Indications for use. To kill fleas and for the prevention...

  9. 21 CFR 520.2130 - Spinosad.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... weight. (ii) Indications for use. To kill fleas and for the prevention and treatment of flea infestations... mg per kilogram) of body weight. (ii) Indications for use. To kill fleas and for the prevention...

  10. 21 CFR 520.2130 - Spinosad.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... in § 510.600 of this chapter. (c) Conditions of use in dogs—(1) Amount. Administer tablets once a... felis) on dogs for 1 month. (3) Limitations. Federal law restricts this drug to use by or on the...

  11. 21 CFR 520.2130 - Spinosad.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... in § 510.600 of this chapter. (c) Conditions of use in dogs—(1) Amount. Administer tablets once a... felis) on dogs for 1 month. (3) Limitations. Federal law restricts this drug to use by or on the...

  12. 75 FR 60321 - Spinosad; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-30

    ... entities may include, but are not limited to those engaged in the following activities: Crop production (NAICS code 111). Animal production (NAICS code 112). Food manufacturing (NAICS code 311). Pesticide...-5805. II. Summary of Petitioned-For Tolerance In the Federal Register of October 26, 2009 (74 FR...

  13. Evolving role of pharmaceutical physicians in the industry: Indian perspective

    PubMed Central

    Patil, Anant; Rajadhyaksha, Viraj

    2012-01-01

    The Indian pharmaceutical industry, like any other industry, has undergone significant change in the last decade. The role of a Medical advisor has always been of paramount importance in the pharmaceutical companies in India. On account of the evolving medical science and the competitive environment, the medical advisor's role is also increasingly becoming critical. In India, with changes in regulatory rules, safety surveillance, and concept of medical liaisons, the role of the medical advisor is evolving continuously and is further likely to evolve in the coming years in important areas like health economics, public private partnerships, and strategic planning. PMID:22347701

  14. Heterogeneous edge weights promote epidemic diffusion in weighted evolving networks

    NASA Astrophysics Data System (ADS)

    Duan, Wei; Song, Zhichao; Qiu, Xiaogang

    2016-08-01

    The impact that the heterogeneities of links’ weights have on epidemic diffusion in weighted networks has received much attention. Investigating how heterogeneous edge weights affect epidemic spread is helpful for disease control. In this paper, we study a Reed-Frost epidemic model in weighted evolving networks. Our results indicate that a higher heterogeneity of edge weights leads to higher epidemic prevalence and epidemic incidence at earlier stage of epidemic diffusion in weighted evolving networks. In addition, weighted evolving scale-free networks come with a higher epidemic prevalence and epidemic incidence than unweighted scale-free networks.

  15. Polarization and studies of evolved star mass loss

    NASA Astrophysics Data System (ADS)

    Sargent, Benjamin; Srinivasan, Sundar; Riebel, David; Meixner, Margaret

    2012-05-01

    Polarization studies of astronomical dust have proven very useful in constraining its properties. Such studies are used to constrain the spatial arrangement, shape, composition, and optical properties of astronomical dust grains. Here we explore possible connections between astronomical polarization observations to our studies of mass loss from evolved stars. We are studying evolved star mass loss in the Large Magellanic Cloud (LMC) by using photometry from the Surveying the Agents of a Galaxy's Evolution (SAGE; PI: M. Meixner) Spitzer Space Telescope Legacy program. We use the radiative transfer program 2Dust to create our Grid of Red supergiant and Asymptotic giant branch ModelS (GRAMS), in order to model this mass loss. To model emission of polarized light from evolved stars, however, we appeal to other radiative transfer codes. We probe how polarization observations might be used to constrain the dust shell and dust grain properties of the samples of evolved stars we are studying.

  16. Evolutionary genetics: you are what you evolve to eat.

    PubMed

    Dworkin, Ian; Jones, Corbin D

    2015-04-20

    The evolution of host specialization can potentially limit future evolutionary opportunities. A new study now shows how Drosophila sechellia, specialized on the toxic Morinda fruit, has evolved new nutritional needs influencing its reproduction.

  17. Evolved Stars: Interferometer Baby Food or Staple Diet?

    NASA Astrophysics Data System (ADS)

    Tuthill, Peter

    With their extreme red and infrared luminosities and large apparent diameters, evolved stars have nurtured generations of interferometers (beginning with Michelson's work on Betelgeuse) with unique science programs at attainable resolutions. Furthermore, the inflated photosphere and circumstellar material associated with dying stars presents complex targets with asymmetric structure on many scales encoding a wealth of poorly-understood astrophysics. A brief review the major past milestones and future prospects for interferometry's contribution to studies of circumstellar matter in evolved stars is presented.

  18. Dust in Interstellar Clouds, Evolved Stars and Supernovae

    SciTech Connect

    Hartquist, T. W.; Van Loo, S.; Caselli, P.; Ashmore, I.; Falle, S. A. E. G.

    2008-09-07

    Outflows of pre-main-sequence stars drive shocks into molecular material within 0.01-1 pc of the young stars. The shock-heated gas emits infrared lines of H{sub 2} and H{sub 2}O and millimeter and submillimeter lines of many species including CO, SiO, H{sub 2}S and HCO{sup +}. Dust grains are important charge carriers and play a large role in coupling the magnetic field and flow of neutral gas. Some understanding of the effects of the dust on the dynamics of oblique shocks began to emerge in the 1990s. However, detailed models of these shocks are required for the calculation of the grain sputtering contribution to gas phase abundances of species producing observed emissions. We are developing such models.Some of the molecular species introduced into the gas phase by sputtering in shocks or by thermally driven desorption in radiatively heated hot cores form on grain surfaces. Recently laboratory studies have begun to contribute to the understanding of surface reactions and thermally driven desorption important for the chemistry of star forming clouds.Dusty plasmas are prevalent in many evolved stars just as well as in star forming regions. Radiation pressure on dust plays a significant role in mass loss from some post-main-sequence stars. The mechanisms leading to the formation of carbonaceous dust in the stellar outflows are similar to those important for soot formation in flames. However, nucleation in oxygen-rich outflows is less well understood and remains a challenging research area.Dust is observed in supernova ejecta that have not passed through the reverse shocks that develop in the interaction of ejecta with ambient media. Dust is detected in high redshift galaxies that are sufficiently young that the only stars that could have produced the dust were so massive that they became supernovae. Consequently, the issue of the survival of dust in strong supernova shocks is of considerable interest.

  19. Holographic Imaging of Evolving Laser-Plasma Structures

    SciTech Connect

    Downer, Michael; Shvets, G.

    2014-07-31

    sprinting animal. The object modifies the probe, imprinting information about its structure. Meanwhile, our “reference” probe co-propagates ahead of the object, free of its influence. After the interaction, object and reference combine to record a hologram. For technical reasons, our recording device is a spectrometer (a frequency-measuring device), hence the name “frequency-domain” holography. We read the hologram electronically to obtain a “snapshot” of the object’s average structure as it transits the medium. Our published work shows numerous snapshots of electron density waves (“laser wakes”) in ionized gas (“plasma”), analogous to a water wake behind a boat. Such waves are the basis of tabletop particle accelerators, in which charged particles surf on the light-speed wave, gaining energy. Comparing our snapshots to computer simulations deepens understanding of laser wakes. FDH takes snapshots of objects that are quasi-static --- i.e. like Muybridge’s horse standing still on a treadmill. If the object changes shape, FDH images blur, as when a subject moves while a camera shutter is open. Many laser-generated objects of interest do evolve as they propagate. To overcome this limit of FDH, we developed .... (2) Frequency-Domain Tomography (FDT). In FDT, 5 to 10 probe pulses are fired simultaneously across the object’s path at different angles, like a crossfire of bullets. The object imprints a “streaked” record of its evolution on each probe, which we record as in FDH, then recover a multi-frame “movie” of the object’s evolving structure using algorithms of computerized tomography. When propagation distance exceeds a few millimeters, reconstructed FDT images distort. This is because the lenses that image probes to detector have limited depth of field, like cameras that cannot focus simultaneously on both nearby and distant objects. But some laser-generated objects of interest propagate over meters. For these applications we developed

  20. Low field magnetic resonance imaging

    DOEpatents

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  1. Evolving Darwin's 'most wonderful' plant: ecological steps to a snap-trap.

    PubMed

    Gibson, Thomas C; Waller, Donald M

    2009-08-01

    Among carnivorous plants, Darwin was particularly fascinated by the speed and sensitivity of snap-traps in Dionaea and Aldrovanda. Recent molecular work confirms Darwin's conjecture that these monotypic taxa are sister to Drosera, meaning that snap-traps evolved from a 'flypaper' trap. Transitions include tentacles being modified into trigger hairs and marginal 'teeth', the loss of sticky tentacles, depressed digestive glands, and rapid leaf movement. Pre-adaptations are known for all these traits in Drosera yet snap-traps only evolved once. We hypothesize that selection to catch and retain large insects favored the evolution of elongate leaves and snap-tentacles in Drosera and snap-traps. Although sticky traps efficiently capture small prey, they allow larger prey to escape and may lose nutrients. Dionaea's snap-trap efficiently captures and processes larger prey providing higher, but variable, rewards. We develop a size-selective model and parametrize it with field data to demonstrate how selection to capture larger prey strongly favors snap-traps. As prey become larger, they also become rarer and gain the power to rip leaves, causing returns to larger snap-traps to plateau. We propose testing these hypotheses with specific field data and Darwin-like experiments. The complexity of snap-traps, competition with pitfall traps, and their association with ephemeral habitats all help to explain why this curious adaptation only evolved once. PMID:19573135

  2. Evolving Darwin's 'most wonderful' plant: ecological steps to a snap-trap.

    PubMed

    Gibson, Thomas C; Waller, Donald M

    2009-08-01

    Among carnivorous plants, Darwin was particularly fascinated by the speed and sensitivity of snap-traps in Dionaea and Aldrovanda. Recent molecular work confirms Darwin's conjecture that these monotypic taxa are sister to Drosera, meaning that snap-traps evolved from a 'flypaper' trap. Transitions include tentacles being modified into trigger hairs and marginal 'teeth', the loss of sticky tentacles, depressed digestive glands, and rapid leaf movement. Pre-adaptations are known for all these traits in Drosera yet snap-traps only evolved once. We hypothesize that selection to catch and retain large insects favored the evolution of elongate leaves and snap-tentacles in Drosera and snap-traps. Although sticky traps efficiently capture small prey, they allow larger prey to escape and may lose nutrients. Dionaea's snap-trap efficiently captures and processes larger prey providing higher, but variable, rewards. We develop a size-selective model and parametrize it with field data to demonstrate how selection to capture larger prey strongly favors snap-traps. As prey become larger, they also become rarer and gain the power to rip leaves, causing returns to larger snap-traps to plateau. We propose testing these hypotheses with specific field data and Darwin-like experiments. The complexity of snap-traps, competition with pitfall traps, and their association with ephemeral habitats all help to explain why this curious adaptation only evolved once.

  3. canEvolve: A Web Portal for Integrative Oncogenomics

    PubMed Central

    Yan, Zhenyu; Wang, Xujun; Cao, Qingyi; Munshi, Nikhil C.; Li, Cheng

    2013-01-01

    Background & Objective Genome-wide profiles of tumors obtained using functional genomics platforms are being deposited to the public repositories at an astronomical scale, as a result of focused efforts by individual laboratories and large projects such as the Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium. Consequently, there is an urgent need for reliable tools that integrate and interpret these data in light of current knowledge and disseminate results to biomedical researchers in a user-friendly manner. We have built the canEvolve web portal to meet this need. Results canEvolve query functionalities are designed to fulfill most frequent analysis needs of cancer researchers with a view to generate novel hypotheses. canEvolve stores gene, microRNA (miRNA) and protein expression profiles, copy number alterations for multiple cancer types, and protein-protein interaction information. canEvolve allows querying of results of primary analysis, integrative analysis and network analysis of oncogenomics data. The querying for primary analysis includes differential gene and miRNA expression as well as changes in gene copy number measured with SNP microarrays. canEvolve provides results of integrative analysis of gene expression profiles with copy number alterations and with miRNA profiles as well as generalized integrative analysis using gene set enrichment analysis. The network analysis capability includes storage and visualization of gene co-expression, inferred gene regulatory networks and protein-protein interaction information. Finally, canEvolve provides correlations between gene expression and clinical outcomes in terms of univariate survival analysis. Conclusion At present canEvolve provides different types of information extracted from 90 cancer genomics studies comprising of more than 10,000 patients. The presence of multiple data types, novel integrative analysis for identifying regulators of oncogenesis, network analysis and ability

  4. Research and development of the evolving architecture for beyond the Standard Model

    NASA Astrophysics Data System (ADS)

    Cho, Kihyeon; Kim, Jangho; Kim, Junghyun

    2015-12-01

    The Standard Model (SM) has been successfully validated with the discovery of Higgs boson. However, the model is not yet fully regarded as a complete description. There are efforts to develop phenomenological models that are collectively termed beyond the standard model (BSM). The BSM requires several orders of magnitude more simulations compared with those required for the Higgs boson events. On the other hand, particle physics research involves major investments in hardware coupled with large-scale theoretical and computational efforts along with experiments. These fields include simulation toolkits based on an evolving computing architecture. Using the simulation toolkits, we study particle physics beyond the standard model. Here, we describe the state of this research and development effort for evolving computing architecture of high throughput computing (HTC) and graphic processing units (GPUs) for searching beyond the standard model.

  5. Recoiling Black Holes in Static and Evolving Dark Matter Halo Potential

    NASA Astrophysics Data System (ADS)

    Smole, M.

    2015-12-01

    We follow trajectories of kicked black holes in static and evolving dark matter halo potential. We explore both NFW and Einasto dark matter density distributions. The considered dark matter halos represent hosts of massive spiral and elliptical field galaxies. We study the critical amplitude of kick velocity necessary for complete black hole ejection at various redshifts and find that ˜40 percent lower kick velocities can remove black holes from their host haloes at z=7 compared to z=1. The greatest difference between the static and evolving potential occurs near the critical velocity for black hole ejection and at high redshifts. When NFW and Einasto density distributions are compared ˜30 percent higher kick velocities are needed for complete removal of BHs from dark matter halo described by the NFW profile.

  6. MODELING TO EVOLVE UNDERSTANDING OF THE SHALLOW GROUND WATER FLOW SYSTEM BENEATH THE LIZZIE RESEARCH SITE, NC

    EPA Science Inventory

    The purpose of the modeling effort presented here is to evolve a conceptual model of ground-water flow at the Lizzie, NC research site using analytic solutions and field observations. The resulting analytic element parameterization of boundary conditions, aquifer transmissivitie...

  7. Measuring and comparing evolvability and constraint in multivariate characters.

    PubMed

    Hansen, T F; Houle, D

    2008-09-01

    The Lande equation forms the basis for our understanding of the short-term evolution of quantitative traits in a multivariate context. It predicts the response to selection as the product of an additive genetic variance matrix and a selection gradient. The selection gradient approximates the force and direction of selection, and the genetic variance matrix quantifies the role of the genetic system in evolution. Attempts to understand the evolutionary significance of the genetic variance matrix are hampered by the fact that the majority of the methods used to characterize and compare variance matrices have not been derived in an explicit theoretical context. We use the Lande equation to derive new measures of the ability of a variance matrix to allow or constrain evolution in any direction in phenotype space. Evolvability captures the ability of a population to evolve in the direction of selection when stabilizing selection is absent. Conditional evolvability captures the ability of a population to respond to directional selection in the presence of stabilizing selection on other trait combinations. We then derive measures of character autonomy and integration from these evolvabilities. We study the properties of these measures and show how they can be used to interpret and compare variance matrices. As an illustration, we show that divergence of wing shape in the dipteran family Drosophilidae has proceeded in directions that have relatively high evolvabilities.

  8. The fitness and functionality of culturally evolved communication systems.

    PubMed

    Fay, Nicolas; Garrod, Simon; Roberts, Leo

    2008-11-12

    This paper assesses whether human communication systems undergo the same progressive adaptation seen in animal communication systems and concrete artefacts. Four experiments compared the fitness of ad hoc sign systems created under different conditions when participants play a graphical communication task. Experiment 1 demonstrated that when participants are organized into interacting communities, a series of signs evolve that enhance individual learning and promote efficient decoding. No such benefits are found for signs that result from the local interactions of isolated pairs of interlocutors. Experiments 2 and 3 showed that the decoding benefits associated with community evolved signs cannot be attributed to superior sign encoding or detection. Experiment 4 revealed that naive overseers were better able to identify the meaning of community evolved signs when compared with isolated pair developed signs. Hence, the decoding benefits for community evolved signs arise from their greater residual iconicity. We argue that community evolved sign systems undergo a process of communicative selection and adaptation that promotes optimized sign systems. This results from the interplay between sign diversity and a global alignment constraint; pairwise interaction introduces a range of competing signs and the need to globally align on a single sign-meaning mapping for each referent applies selection pressure.

  9. The fitness and functionality of culturally evolved communication systems.

    PubMed

    Fay, Nicolas; Garrod, Simon; Roberts, Leo

    2008-11-12

    This paper assesses whether human communication systems undergo the same progressive adaptation seen in animal communication systems and concrete artefacts. Four experiments compared the fitness of ad hoc sign systems created under different conditions when participants play a graphical communication task. Experiment 1 demonstrated that when participants are organized into interacting communities, a series of signs evolve that enhance individual learning and promote efficient decoding. No such benefits are found for signs that result from the local interactions of isolated pairs of interlocutors. Experiments 2 and 3 showed that the decoding benefits associated with community evolved signs cannot be attributed to superior sign encoding or detection. Experiment 4 revealed that naive overseers were better able to identify the meaning of community evolved signs when compared with isolated pair developed signs. Hence, the decoding benefits for community evolved signs arise from their greater residual iconicity. We argue that community evolved sign systems undergo a process of communicative selection and adaptation that promotes optimized sign systems. This results from the interplay between sign diversity and a global alignment constraint; pairwise interaction introduces a range of competing signs and the need to globally align on a single sign-meaning mapping for each referent applies selection pressure. PMID:18799421

  10. How Hierarchical Topics Evolve in Large Text Corpora.

    PubMed

    Cui, Weiwei; Liu, Shixia; Wu, Zhuofeng; Wei, Hao

    2014-12-01

    Using a sequence of topic trees to organize documents is a popular way to represent hierarchical and evolving topics in text corpora. However, following evolving topics in the context of topic trees remains difficult for users. To address this issue, we present an interactive visual text analysis approach to allow users to progressively explore and analyze the complex evolutionary patterns of hierarchical topics. The key idea behind our approach is to exploit a tree cut to approximate each tree and allow users to interactively modify the tree cuts based on their interests. In particular, we propose an incremental evolutionary tree cut algorithm with the goal of balancing 1) the fitness of each tree cut and the smoothness between adjacent tree cuts; 2) the historical and new information related to user interests. A time-based visualization is designed to illustrate the evolving topics over time. To preserve the mental map, we develop a stable layout algorithm. As a result, our approach can quickly guide users to progressively gain profound insights into evolving hierarchical topics. We evaluate the effectiveness of the proposed method on Amazon's Mechanical Turk and real-world news data. The results show that users are able to successfully analyze evolving topics in text data.

  11. The value of monitoring to control evolving populations

    PubMed Central

    Fischer, Andrej; Mustonen, Ville

    2015-01-01

    Populations can evolve to adapt to external changes. The capacity to evolve and adapt makes successful treatment of infectious diseases and cancer difficult. Indeed, therapy resistance has become a key challenge for global health. Therefore, ideas of how to control evolving populations to overcome this threat are valuable. Here we use the mathematical concepts of stochastic optimal control to study what is needed to control evolving populations. Following established routes to calculate control strategies, we first study how a polymorphism can be maintained in a finite population by adaptively tuning selection. We then introduce a minimal model of drug resistance in a stochastically evolving cancer cell population and compute adaptive therapies. When decisions are in this manner based on monitoring the response of the tumor, this can outperform established therapy paradigms. For both case studies, we demonstrate the importance of high-resolution monitoring of the target population to achieve a given control objective, thus quantifying the intuition that to control, one must monitor. PMID:25587136

  12. How Hierarchical Topics Evolve in Large Text Corpora.

    PubMed

    Cui, Weiwei; Liu, Shixia; Wu, Zhuofeng; Wei, Hao

    2014-12-01

    Using a sequence of topic trees to organize documents is a popular way to represent hierarchical and evolving topics in text corpora. However, following evolving topics in the context of topic trees remains difficult for users. To address this issue, we present an interactive visual text analysis approach to allow users to progressively explore and analyze the complex evolutionary patterns of hierarchical topics. The key idea behind our approach is to exploit a tree cut to approximate each tree and allow users to interactively modify the tree cuts based on their interests. In particular, we propose an incremental evolutionary tree cut algorithm with the goal of balancing 1) the fitness of each tree cut and the smoothness between adjacent tree cuts; 2) the historical and new information related to user interests. A time-based visualization is designed to illustrate the evolving topics over time. To preserve the mental map, we develop a stable layout algorithm. As a result, our approach can quickly guide users to progressively gain profound insights into evolving hierarchical topics. We evaluate the effectiveness of the proposed method on Amazon's Mechanical Turk and real-world news data. The results show that users are able to successfully analyze evolving topics in text data. PMID:26356942

  13. Parabolic equation modeling of high frequency acoustic transmission with an evolving sea surface.

    PubMed

    Senne, J; Song, A; Badiey, M; Smith, K B

    2012-09-01

    The present paper examines the temporal evolution of acoustic fields by modeling forward propagation subject to sea surface dynamics with time scales of less than a second to tens of seconds. A time-evolving rough sea surface model is combined with a rough surface formulation of a parabolic equation model for predicting time-varying acoustic fields. Surface waves are generated from surface wave spectra, and stepped in time using a Runge-Kutta integration technique applied to linear evolution equations. This evolving, range-dependent surface information is combined with other environmental parameters and input to the acoustic model, giving an approximation of the time-varying acoustic field. The wide-angle parabolic equation model manages the rough sea surfaces by molding them into the boundary conditions for calculations of the near-surface acoustic field. This merged acoustic model is validated using concurrently-collected acoustic and environmental information, including surface wave spectra. Data to model comparisons demonstrate that the model is able to approximate the ensemble-averaged acoustic intensity at ranges of about a kilometer for acoustic signals of around 15 kHz. Furthermore, the model is shown to capture variations due to surface fluctuations occurring over time scales of less than a second to tens of seconds.

  14. Evolving mobile robots able to display collective behaviors.

    PubMed

    Baldassarre, Gianluca; Nolfi, Stefano; Parisi, Domenico

    2003-01-01

    We present a set of experiments in which simulated robots are evolved for the ability to aggregate and move together toward a light target. By developing and using quantitative indexes that capture the structural properties of the emerged formations, we show that evolved individuals display interesting behavioral patterns in which groups of robots act as a single unit. Moreover, evolved groups of robots with identical controllers display primitive forms of situated specialization and play different behavioral functions within the group according to the circumstances. Overall, the results presented in the article demonstrate that evolutionary techniques, by exploiting the self-organizing behavioral properties that emerge from the interactions between the robots and between the robots and the environment, are a powerful method for synthesizing collective behavior. PMID:14556687

  15. Synthesis of Evolving Cells for Reconfigurable Manufacturing Systems

    NASA Astrophysics Data System (ADS)

    Padayachee, J.; Bright, G.

    2014-07-01

    The concept of Reconfigurable Manufacturing Systems (RMSs) was formulated due to the global necessity for production systems that are able to economically evolve according to changes in markets and products. Technologies and design methods are under development to enable RMSs to exhibit transformable system layouts, reconfigurable processes, cells and machines. Existing factory design methods and software have not yet advanced to include reconfigurable manufacturing concepts. This paper presents the underlying group technology framework for the design of manufacturing cells that are able to evolve according to a changing product mix by mechanisms of reconfiguration. The framework is based on a Norton- Bass forecast and time variant BOM models. An adaptation of legacy group technology methods is presented for the synthesis of evolving cells and two optimization problems are presented within this context.

  16. Evolving Lorentzian wormholes supported by phantom matter and cosmological constant

    SciTech Connect

    Cataldo, Mauricio; Campo, Sergio del; Minning, Paul; Salgado, Patricio

    2009-01-15

    In this paper we study the possibility of sustaining an evolving wormhole via exotic matter made of phantom energy in the presence of a cosmological constant. We derive analytical evolving wormhole geometries by supposing that the radial tension of the phantom matter, which is negative to the radial pressure, and the pressure measured in the tangential directions have barotropic equations of state with constant state parameters. In this case the presence of a cosmological constant ensures accelerated expansion of the wormhole configurations. More specifically, for positive cosmological constant we have wormholes which expand forever and, for negative cosmological constant we have wormholes which expand to a maximum value and then recollapse. At spatial infinity the energy density and the pressures of the anisotropic phantom matter threading the wormholes vanish; thus these evolving wormholes are asymptotically vacuum {lambda}-Friedmann models with either open or closed or flat topologies.

  17. Evolving Systems: An Outcome of Fondest Hopes and Wildest Dreams

    NASA Technical Reports Server (NTRS)

    Frost, Susan A.; Balas, Mark J.

    2012-01-01

    New theory is presented for evolving systems, which are autonomously controlled subsystems that self-assemble into a new evolved system with a higher purpose. Evolving systems of aerospace structures often require additional control when assembling to maintain stability during the entire evolution process. This is the concept of Adaptive Key Component Control that operates through one specific component to maintain stability during the evolution. In addition, this control must often overcome persistent disturbances that occur while the evolution is in progress. Theoretical results will be presented for Adaptive Key Component control for persistent disturbance rejection. An illustrative example will demonstrate the Adaptive Key Component controller on a system composed of rigid body and flexible body modes.

  18. Hybridization Reveals the Evolving Genomic Architecture of Speciation

    PubMed Central

    Kronforst, Marcus R.; Hansen, Matthew E.B.; Crawford, Nicholas G.; Gallant, Jason R.; Zhang, Wei; Kulathinal, Rob J.; Kapan, Durrell D.; Mullen, Sean P.

    2014-01-01

    SUMMARY The rate at which genomes diverge during speciation is unknown, as are the physical dynamics of the process. Here, we compare full genome sequences of 32 butterflies, representing five species from a hybridizing Heliconius butterfly community, to examine genome-wide patterns of introgression and infer how divergence evolves during the speciation process. Our analyses reveal that initial divergence is restricted to a small fraction of the genome, largely clustered around known wing-patterning genes. Over time, divergence evolves rapidly, due primarily to the origin of new divergent regions. Furthermore, divergent genomic regions display signatures of both selection and adaptive introgression, demonstrating the link between microevolutionary processes acting within species and the origin of species across macroevolutionary timescales. Our results provide a uniquely comprehensive portrait of the evolving species boundary due to the role that hybridization plays in reducing the background accumulation of divergence at neutral sites. PMID:24183670

  19. The evolved basis and adaptive functions of cognitive distortions.

    PubMed

    Gilbert, P

    1998-12-01

    This paper explores common cognitive distortions from the perspective of evolutionary psychology. It is suggested that cognitive distortions are natural consequences of using fast track defensive algorithms that are sensitive to threat. In various contexts, especially those of threat, humans evolved to think adaptively rather than logically. Hence cognitive distortions are not strictly errors in brain functioning and it can be useful to inform patients that 'negative thinking' may be dysfunctional but is a reflection of basic brain design and not personal irrationality. The evolved nature of cognitive distortions has been implicit in cognitive therapy from its early days (Beck, 1963; Ellis, 1962) but has not been fully articulated in what is now known about evolved mental processes. Many forms of cognitive distortion can be seen to use the (previously) adaptive heuristic of better safe than sorry.

  20. Active Printed Materials for Complex Self-Evolving Deformations

    NASA Astrophysics Data System (ADS)

    Raviv, Dan; Zhao, Wei; McKnelly, Carrie; Papadopoulou, Athina; Kadambi, Achuta; Shi, Boxin; Hirsch, Shai; Dikovsky, Daniel; Zyracki, Michael; Olguin, Carlos; Raskar, Ramesh; Tibbits, Skylar

    2014-12-01

    We propose a new design of complex self-evolving structures that vary over time due to environmental interaction. In conventional 3D printing systems, materials are meant to be stable rather than active and fabricated models are designed and printed as static objects. Here, we introduce a novel approach for simulating and fabricating self-evolving structures that transform into a predetermined shape, changing property and function after fabrication. The new locally coordinated bending primitives combine into a single system, allowing for a global deformation which can stretch, fold and bend given environmental stimulus.

  1. Active printed materials for complex self-evolving deformations.

    PubMed

    Raviv, Dan; Zhao, Wei; McKnelly, Carrie; Papadopoulou, Athina; Kadambi, Achuta; Shi, Boxin; Hirsch, Shai; Dikovsky, Daniel; Zyracki, Michael; Olguin, Carlos; Raskar, Ramesh; Tibbits, Skylar

    2014-12-18

    We propose a new design of complex self-evolving structures that vary over time due to environmental interaction. In conventional 3D printing systems, materials are meant to be stable rather than active and fabricated models are designed and printed as static objects. Here, we introduce a novel approach for simulating and fabricating self-evolving structures that transform into a predetermined shape, changing property and function after fabrication. The new locally coordinated bending primitives combine into a single system, allowing for a global deformation which can stretch, fold and bend given environmental stimulus.

  2. The cartography of pain: the evolving contribution of pain maps.

    PubMed

    Schott, Geoffrey D

    2010-09-01

    Pain maps are nowadays widely used in clinical practice. This article aims to critically review the fundamental principles that underlie the mapping of pain, to analyse the evolving iconography of pain maps and their sometimes straightforward and sometimes contentious nature when used in the clinic, and to draw attention to some more recent developments in mapping pain. It is concluded that these maps are intriguing and evolving cartographic tools which can be used for depicting not only the spatial features but also the interpretative or perceptual components and accompaniments of pain.

  3. Research at the Crossroads: How Intellectual Initiatives across Disciplines Evolve

    ERIC Educational Resources Information Center

    Frost, Susan H.; Jean, Paul M.; Teodorescu, Daniel; Brown, Amy B.

    2004-01-01

    How do intellectual initiatives across disciplines evolve? This qualitative case study of 11 interdisciplinary research initiatives at Emory University identifies key factors in their development: the passionate commitments of scholarly leaders, the presence of strong collegial networks, access to timely and multiple resources, flexible practices,…

  4. Coevolution Drives the Emergence of Complex Traits and Promotes Evolvability

    PubMed Central

    Zaman, Luis; Meyer, Justin R.; Devangam, Suhas; Bryson, David M.; Lenski, Richard E.; Ofria, Charles

    2014-01-01

    The evolution of complex organismal traits is obvious as a historical fact, but the underlying causes—including the role of natural selection—are contested. Gould argued that a random walk from a necessarily simple beginning would produce the appearance of increasing complexity over time. Others contend that selection, including coevolutionary arms races, can systematically push organisms toward more complex traits. Methodological challenges have largely precluded experimental tests of these hypotheses. Using the Avida platform for digital evolution, we show that coevolution of hosts and parasites greatly increases organismal complexity relative to that otherwise achieved. As parasites evolve to counter the rise of resistant hosts, parasite populations retain a genetic record of past coevolutionary states. As a consequence, hosts differentially escape by performing progressively more complex functions. We show that coevolution's unique feedback between host and parasite frequencies is a key process in the evolution of complexity. Strikingly, the hosts evolve genomes that are also more phenotypically evolvable, similar to the phenomenon of contingency loci observed in bacterial pathogens. Because coevolution is ubiquitous in nature, our results support a general model whereby antagonistic interactions and natural selection together favor both increased complexity and evolvability. PMID:25514332

  5. Evolving Nature of Sexual Orientation and Gender Identity

    ERIC Educational Resources Information Center

    Jourian, T. J.

    2015-01-01

    This chapter discusses the historical and evolving terminology, constructs, and ideologies that inform the language used by those who are lesbian, gay, bisexual, and same-gender loving, who may identify as queer, as well as those who are members of trans* communities from multiple and intersectional perspectives.

  6. Optimists' Creed: Brave New Cyberlearning, Evolving Utopias (Circa 2041)

    ERIC Educational Resources Information Center

    Burleson, Winslow; Lewis, Armanda

    2016-01-01

    This essay imagines the role that artificial intelligence innovations play in the integrated living, learning and research environments of 2041. Here, in 2041, in the context of increasingly complex wicked challenges, whose solutions by their very nature continue to evade even the most capable experts, society and technology have co-evolved to…

  7. Does evolving the future preclude learning from it?

    PubMed

    Dowrick, Peter W

    2014-08-01

    Despite its considerable length, this article proposes a theory of human behavioral science that eschews half the evidence. There is irony in the title "Evolving the Future" when the featured examples of intentional change represent procedures that build slowly on the past. Has an opportunity been missed, or is an evolutionary perspective simply incompatible with learning from the future? PMID:25162866

  8. Hip Hop Is Now: An Evolving Youth Culture

    ERIC Educational Resources Information Center

    Taylor, Carl; Taylor, Virgil

    2007-01-01

    Emerging from Rap music, Hip Hop has become a lifestyle to many modern youth around the world. Embodying both creativity and controversy, Hip Hop mirrors the values, violence, and hypocrisy of modern culture. The authors dispel some of the simplistic views that surround this evolving youth movement embraced by millions of young people who are…

  9. The Evolving Military Learner Population: A Review of the Literature

    ERIC Educational Resources Information Center

    Ford, Kate; Vignare, Karen

    2015-01-01

    This literature review examines the evolving online military learner population with emphasis on current generation military learners, who are most frequently Post-9/11 veterans. The review synthesizes recent scholarly and grey literature on military learner demographics and attributes, college experiences, and academic outcomes against a backdrop…

  10. Do Infants Possess an Evolved Spider-Detection Mechanism?

    ERIC Educational Resources Information Center

    Rakison, David H.; Derringer, Jaime

    2008-01-01

    Previous studies with various non-human animals have revealed that they possess an evolved predator recognition mechanism that specifies the appearance of recurring threats. We used the preferential looking and habituation paradigms in three experiments to investigate whether 5-month-old human infants have a perceptual template for spiders that…

  11. A Conceptual Framework for Evolving, Recommender Online Learning Systems

    ERIC Educational Resources Information Center

    Peiris, K. Dharini Amitha; Gallupe, R. Brent

    2012-01-01

    A comprehensive conceptual framework is developed and described for evolving recommender-driven online learning systems (ROLS). This framework describes how such systems can support students, course authors, course instructors, systems administrators, and policy makers in developing and using these ROLS. The design science information systems…

  12. Today`s control systems evolved from early pioneers` dreams

    SciTech Connect

    Smith, D.J.

    1996-04-01

    In the last 100 years, power plant controls have evolved from manual operation and simple instruments to automatic state-of-the-art computerized control systems using smart instruments. This article traces the evolution of controls. The topics of the article include early control systems, developments in the early 20th century, Bailey controls, and developments in the late 20th century.

  13. You 3.0: The Most Important Evolving Technology

    ERIC Educational Resources Information Center

    Tamarkin, Molly; Bantz, David A.; Childs, Melody; diFilipo, Stephen; Landry, Stephen G.; LoPresti, Frances; McDonald, Robert H.; McGuthry, John W.; Meier, Tina; Rodrigo, Rochelle; Sparrow, Jennifer; Diggs, D. Teddy; Yang, Catherine W.

    2010-01-01

    That technology evolves is a given. Not as well understood is the impact of technological evolution on each individual--on oneself, one's skill development, one's career, and one's relationship with the work community. The authors believe that everyone in higher education will become an IT worker and that IT workers will be managing a growing…

  14. The Evolving Understanding of the Construct of Intellectual Disability

    ERIC Educational Resources Information Center

    Schalock, Robert L.

    2011-01-01

    This article addresses two major areas concerned with the evolving understanding of the construct of intellectual disability. The first part of the article discusses current answers to five critical questions that have revolved around the general question, "What is Intellectual Disability?" These five are what to call the phenomenon, how to…

  15. Evolving Strategies for Cancer and Autoimmunity: Back to the Future

    PubMed Central

    Lane, Peter J. L.; McConnell, Fiona M.; Anderson, Graham; Nawaf, Maher G.; Gaspal, Fabrina M.; Withers, David R.

    2014-01-01

    Although current thinking has focused on genetic variation between individuals and environmental influences as underpinning susceptibility to both autoimmunity and cancer, an alternative view is that human susceptibility to these diseases is a consequence of the way the immune system evolved. It is important to remember that the immunological genes that we inherit and the systems that they control were shaped by the drive for reproductive success rather than for individual survival. It is our view that human susceptibility to autoimmunity and cancer is the evolutionarily acceptable side effect of the immune adaptations that evolved in early placental mammals to accommodate a fundamental change in reproductive strategy. Studies of immune function in mammals show that high affinity antibodies and CD4 memory, along with its regulation, co-evolved with placentation. By dissection of the immunologically active genes and proteins that evolved to regulate this step change in the mammalian immune system, clues have emerged that may reveal ways of de-tuning both effector and regulatory arms of the immune system to abrogate autoimmune responses whilst preserving protection against infection. Paradoxically, it appears that such a detuned and deregulated immune system is much better equipped to mount anti-tumor immune responses against cancers. PMID:24782861

  16. Institutional Change of Universities as a Problem of Evolving Boundaries

    ERIC Educational Resources Information Center

    Vakkuri, Jarmo

    2004-01-01

    This paper examines institutional change in universities from the perspective of the notion of "boundaries". The paper asks: how can some of the most important regulatory and administrative changes in universities be understood in the framework of evolving boundaries? Two areas are studied empirically. First, the third mission of universities is…

  17. Tensions inherent in the evolving role of the infection preventionist

    PubMed Central

    Conway, Laurie J.; Raveis, Victoria H.; Pogorzelska-Maziarz, Monika; Uchida, May; Stone, Patricia W.; Larson, Elaine L.

    2014-01-01

    Background The role of infection preventionists (IPs) is expanding in response to demands for quality and transparency in health care. Practice analyses and survey research have demonstrated that IPs spend a majority of their time on surveillance and are increasingly responsible for prevention activities and management; however, deeper qualitative aspects of the IP role have rarely been explored. Methods We conducted a qualitative content analysis of in-depth interviews with 19 IPs at hospitals throughout the United States to describe the current IP role, specifically the ways that IPs effect improvements and the facilitators and barriers they face. Results The narratives document that the IP role is evolving in response to recent changes in the health care landscape and reveal that this progression is associated with friction and uncertainty. Tensions inherent in the evolving role of the IP emerged from the interviews as 4 broad themes: (1) expanding responsibilities outstrip resources, (2) shifting role boundaries create uncertainty, (3) evolving mechanisms of influence involve trade-offs, and (4) the stress of constant change is compounded by chronic recurring challenges. Conclusion Advances in implementation science, data standardization, and training in leadership skills are needed to support IPs in their evolving role. PMID:23880116

  18. An Evolved Wavelet Library Based on Genetic Algorithm

    PubMed Central

    Vaithiyanathan, D.; Seshasayanan, R.; Kunaraj, K.; Keerthiga, J.

    2014-01-01

    As the size of the images being captured increases, there is a need for a robust algorithm for image compression which satiates the bandwidth limitation of the transmitted channels and preserves the image resolution without considerable loss in the image quality. Many conventional image compression algorithms use wavelet transform which can significantly reduce the number of bits needed to represent a pixel and the process of quantization and thresholding further increases the compression. In this paper the authors evolve two sets of wavelet filter coefficients using genetic algorithm (GA), one for the whole image portion except the edge areas and the other for the portions near the edges in the image (i.e., global and local filters). Images are initially separated into several groups based on their frequency content, edges, and textures and the wavelet filter coefficients are evolved separately for each group. As there is a possibility of the GA settling in local maximum, we introduce a new shuffling operator to prevent the GA from this effect. The GA used to evolve filter coefficients primarily focuses on maximizing the peak signal to noise ratio (PSNR). The evolved filter coefficients by the proposed method outperform the existing methods by a 0.31 dB improvement in the average PSNR and a 0.39 dB improvement in the maximum PSNR. PMID:25405225

  19. Coevolution drives the emergence of complex traits and promotes evolvability.

    PubMed

    Zaman, Luis; Meyer, Justin R; Devangam, Suhas; Bryson, David M; Lenski, Richard E; Ofria, Charles

    2014-12-01

    The evolution of complex organismal traits is obvious as a historical fact, but the underlying causes--including the role of natural selection--are contested. Gould argued that a random walk from a necessarily simple beginning would produce the appearance of increasing complexity over time. Others contend that selection, including coevolutionary arms races, can systematically push organisms toward more complex traits. Methodological challenges have largely precluded experimental tests of these hypotheses. Using the Avida platform for digital evolution, we show that coevolution of hosts and parasites greatly increases organismal complexity relative to that otherwise achieved. As parasites evolve to counter the rise of resistant hosts, parasite populations retain a genetic record of past coevolutionary states. As a consequence, hosts differentially escape by performing progressively more complex functions. We show that coevolution's unique feedback between host and parasite frequencies is a key process in the evolution of complexity. Strikingly, the hosts evolve genomes that are also more phenotypically evolvable, similar to the phenomenon of contingency loci observed in bacterial pathogens. Because coevolution is ubiquitous in nature, our results support a general model whereby antagonistic interactions and natural selection together favor both increased complexity and evolvability.

  20. Evolvability suppression to stabilize far-sighted adaptations.

    PubMed

    Altenberg, Lee

    2005-01-01

    The opportunistic character of adaptation through natural selection can lead to evolutionary pathologies--situations in which traits evolve that promote the extinction of the population. Such pathologies include imprudent predation and other forms of habitat overexploitation, or the tragedy of the commons, adaptation to temporally unreliable resources, cheating and other antisocial behavior, infectious pathogen carrier states, parthenogenesis, and cancer, an intraorganismal evolutionary pathology. It is known that hierarchical population dynamics can protect a population from invasion by pathological genes. Can it also alter the genotype so as to prevent the generation of such genes in the first place, that is, suppress the evolvability of evolutionary pathologies? A model is constructed in which one locus controls the expression of the pathological trait, and a series of modifier loci exist that can prevent the expression of this trait. It is found that multiple evolvability checkpoint genes can evolve to prevent the generation of variants that cause evolutionary pathologies. The consequences of this finding are discussed.

  1. The Evolving Theme of Teaching Multicultural Art Education. Monograph Series.

    ERIC Educational Resources Information Center

    La Pierre, Sharon Greenleaf, Ed.; Ballengee-Morris, Christine, Ed.

    This publication, sponsored by the U.S. Society of Education through Art (USSEA) as a forum of past presidents involving audience participation, aims to stimulate dialogue on the evolving theme of teaching multicultural issues and what affects student learning. Session participants were past presidents of the USSEA who prepared written statements…

  2. The Evolving Significance of Race: Living, Learning, and Teaching

    ERIC Educational Resources Information Center

    Hughes, Sherick A., Ed.; Berry, Theodorea Regina, Ed.

    2012-01-01

    Individuals are living, learning, and teaching by questioning how to address race in a society that consistently prefers to see itself as colorblind, a society claiming to seek a "post-racial" existence. This edited volume offers evidence of the evolving significance of race from a diverse group of male and female contributors self-identifying as…

  3. To evolve an ear: Epistemological implications of Gordon Pask`s electrochemical devices

    SciTech Connect

    Cariani, P.

    1993-12-31

    In the late 1950`s Gordon Pask constructed several electrochemical devices having emergent sensory capabilities. These control systems possessed the ability to adaptively construct their own sensors, thereby choosing the relationship between their internal states and the world at large. Devices were built that evolved de novo sensitivity to sound or magnetic fields. Pask`s devices have far-reaching implications for artificial intelligence, self-constructing devices, theories of observers and epistemically-autonomous agents, theories of functional emergence, machine creativity, and the limits of contemporary machine learning paradigms. 44 refs.

  4. A flexible method to evolve collisional systems and their tidal debris in external potentials

    NASA Astrophysics Data System (ADS)

    Renaud, Florent; Gieles, Mark

    2015-04-01

    We introduce a numerical method to integrate tidal effects on collisional systems, using any definition of the external potential as a function of space and time. Rather than using a linearization of the tidal field, this new method follows a differential technique to numerically evaluate the tidal acceleration and its time derivative. These are then used to integrate the motions of the components of the collisional systems, like stars in star clusters, using a predictor-corrector scheme. The versatility of this approach allows the study of star clusters, including their tidal tails, in complex, multicomponents, time-evolving external potentials. The method is implemented in the code NBODY6.

  5. NASAs Evolvable Mars Campaign: Mars Moons Robotic Precursor

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael L.; Abercromby, Andrew F. J.; Abell, Paul A.; Love, Stanley G.; Lee, David E.; Chappell, Steven P.; Howe, A. Scott; Friedensen, Victoria

    2015-01-01

    Human exploration missions to the moons of Mars are being considered within NASA's Evolvable Mars Campaign (EMC) as an intermediate step for eventual human exploration and pioneering of the surface of Mars. A range of mission architectures is being evaluated in which human crews would explore one or both moons for as little as 14 days or for as long as 500 days with a variety of orbital and surface habitation and mobility options being considered. Relatively little is known about the orbital, surface, or subsurface characteristics of either moon. This makes them interesting but challenging destinations for human exploration missions during which crewmembers must be able to effectively conduct scientific exploration without being exposed to undue risks due to radiation, dust, micrometeoroids, or other hazards. A robotic precursor mission to one or both moons will be required to provide data necessary for the design and operation of subsequent human systems and for the identification and prioritization of scientific exploration objectives. This paper identifies and discusses considerations for the design of such a precursor mission based on current human mission architectures. Objectives of a Mars' moon precursor in support of human missions are expected to include: 1) identifying hazards on the surface and the orbital environment at up to 50-km distant retrograde orbits; 2) collecting data on physical characteristics for planning of detailed human proximity and surface operations; 3) performing remote sensing and in situ science investigations to refine and focus future human scientific activities; and 4) prospecting for in situ resource utilization. These precursor objectives can be met through a combination or remote sensing (orbital) and in-situ (surface) measurements. Analysis of spacecraft downlink signals using radio science techniques would measure the moon's mass, mass distribution, and gravity field, which will be necessary to enable trajectory planning

  6. Evolvable mathematical models: A new artificial Intelligence paradigm

    NASA Astrophysics Data System (ADS)

    Grouchy, Paul

    We develop a novel Artificial Intelligence paradigm to generate autonomously artificial agents as mathematical models of behaviour. Agent/environment inputs are mapped to agent outputs via equation trees which are evolved in a manner similar to Symbolic Regression in Genetic Programming. Equations are comprised of only the four basic mathematical operators, addition, subtraction, multiplication and division, as well as input and output variables and constants. From these operations, equations can be constructed that approximate any analytic function. These Evolvable Mathematical Models (EMMs) are tested and compared to their Artificial Neural Network (ANN) counterparts on two benchmarking tasks: the double-pole balancing without velocity information benchmark and the challenging discrete Double-T Maze experiments with homing. The results from these experiments show that EMMs are capable of solving tasks typically solved by ANNs, and that they have the ability to produce agents that demonstrate learning behaviours. To further explore the capabilities of EMMs, as well as to investigate the evolutionary origins of communication, we develop NoiseWorld, an Artificial Life simulation in which interagent communication emerges and evolves from initially noncommunicating EMM-based agents. Agents develop the capability to transmit their x and y position information over a one-dimensional channel via a complex, dialogue-based communication scheme. These evolved communication schemes are analyzed and their evolutionary trajectories examined, yielding significant insight into the emergence and subsequent evolution of cooperative communication. Evolved agents from NoiseWorld are successfully transferred onto physical robots, demonstrating the transferability of EMM-based AIs from simulation into physical reality.

  7. The Dynamical Classification of Centaurs which Evolve into Comets

    NASA Astrophysics Data System (ADS)

    Wood, Jeremy R.; Horner, Jonathan; Hinse, Tobias; Marsden, Stephen; Swinburne University of Technology

    2016-10-01

    Centaurs are small Solar system bodies with semi-major axes between Jupiter and Neptune and perihelia beyond Jupiter. Centaurs can be further subclassified into two dynamical categories – random walk and resonance hopping. Random walk Centaurs have mean square semi-major axes (< a2 >) which vary in time according to a generalized diffusion equation where < a2 > ~t2H. H is the Hurst exponent with 0 < H < 1, and t is time. The behavior of < a2 > for resonance hopping Centaurs is not well described by generalized diffusion.The aim of this study is to determine which dynamical type of Centaur is most likely to evolve into each class of comet. 31,722 fictional massless test particles were integrated for 3 Myr in the 6-body problem (Sun, Jovian planets, test particle). Initially each test particle was a member of one of four groups. The semi-major axes of all test particles in a group were clustered within 0.27 au from a first order, interior Mean Motion resonance of Neptune. The resonances were centered at 18.94 au, 22.95 au, 24.82 au and 28.37 au.If the perihelion of a test particle reached < 4 au then the test particle was considered to be a comet and classified as either a random walk or resonance hopping Centaur. The results showed that over 4,000 test particles evolved into comets within 3 Myr. 59% of these test particles were random walk and 41% were resonance hopping. The behavior of the semi-major axis in time was usually well described by generalized diffusion for random walk Centaurs (ravg = 0.98) and poorly described for resonance hopping Centaurs (ravg = 0.52). The average Hurst exponent was 0.48 for random walk Centaurs and 0.20 for resonance hopping Centaurs. Random walk Centaurs were more likely to evolve into short period comets while resonance hopping Centaurs were more likely to evolve into long period comets. For each initial cluster, resonance hopping Centaurs took longer to evolve into comets than random walk Centaurs. Overall the population of

  8. Cell biology, molecular embryology, Lamarckian and Darwinian selection as evolvability.

    PubMed

    Hoenigsberg, H

    2003-01-01

    The evolvability of vertebrate systems involves various mechanisms that eventually generate cooperative and nonlethal functional variation on which Darwinian selection can operate. It is a truism that to get vertebrate animals to develop a coherent machine they first had to inherit the right multicellular ontogeny. The ontogeny of a metazoan involves cell lineages that progressively deny their own capacity for increase and for totipotency in benefit of the collective interest of the individual. To achieve such cell altruism Darwinian dynamics rescinded its original unicellular mandate to reproduce. The distinction between heritability at the level of the cell lineage and at the level of the individual is crucial. However, its implications have seldom been explored in depth. While all out reproduction is the Darwinian measure of success among unicellular organisms, a high replication rate of cell lineages within the organism may be deleterious to the individual as a functional unit. If a harmoniously functioning unit is to evolve, mechanisms must have evolved whereby variants that increase their own replication rate by failing to accept their own somatic duties are controlled. For questions involving organelle origins, see Godelle and Reboud, 1995 and Hoekstra, 1990. In other words, modifiers of conflict that control cell lineages with conflicting genes and new mutant replication rates that deviate from their somatic duties had to evolve. Our thesis is that selection at the level of the (multicellular) individual must have opposed selection at the level of the cell lineage. The metazoan embryo is not immune to this conflict especially with the evolution of set-aside cells and other modes of self-policing modifiers (Blackstone and Ellison, 1998; Ransick et al., 1996. In fact, the conflict between the two selection processes permitted a Lamarckian soma-to-germline feedback loop. This new element in metazoan ontogeny became the evolvability of the vertebrate adaptive

  9. Electron Acceleration in a Dynamically Evolved Current Sheet of Solar Coronal Conditions

    NASA Astrophysics Data System (ADS)

    Shaohua, Z.; Du, A.; Feng, X.

    2012-12-01

    Electron acceleration in a drastically evolved current sheet of solar coronal conditions is investigated via the combined resistive Magnetohydrodynamics (MHD) and test particle approaches. With high magnetic Reynolds number, the long-thin current sheet is tearing into a chain of magnetic islands, which grow in size and coalesce together. The acceleration of electrons are explored in three typical evolvement phases: when several large magnetic islands are formed (phase1), two of them are approaching each other (phase2) and almost merging into a "monster" magnetic island (phase3). The results show that for all the three phases electrons with an initially Maxwellian distribution evolve into a heavy-tailed distribution and more than 20% of the electrons can be accelerated higher than 200 keV within 0.1 second and some of them can even be energized up to MeV ranges. Most of the energetic electrons move around the magnetic islands in clockwise direction (anti-parallel to the magnetic field lines), drifting in the -Z direction. The energetic electrons with 10 keV < Ek < 200 keV are located outside the magnetic separatrices, where parallel electric field (Ep) is small. The electrons with 200 keV < Ek < 5000 keV are distributed inside the magnetic islands where Ep is moderate large but have complex structures. The electrons with Ek > 5000 keV are located around the outer regions of the magnetic islands or at the core regions of the magnetic islands. Some of the most energetic electrons even appear in the small secondary magnetic islands that are embedded in the diusion regions in between the magnetic islands. It is the trapping eect of the magnetic islands and the distributions of Ep that determine the acceleration processes and space distribution of the energetic electrons.

  10. Network connections that evolve to circumvent the inverse optics problem.

    PubMed

    Ng, Cherlyn; Sundararajan, Janani; Hogan, Michael; Purves, Dale

    2013-01-01

    A fundamental problem in vision science is how useful perceptions and behaviors arise in the absence of information about the physical sources of retinal stimuli (the inverse optics problem). Psychophysical studies show that human observers contend with this problem by using the frequency of occurrence of stimulus patterns in cumulative experience to generate percepts. To begin to understand the neural mechanisms underlying this strategy, we examined the connectivity of simple neural networks evolved to respond according to the cumulative rank of stimulus luminance values. Evolved similarities with the connectivity of early level visual neurons suggests that biological visual circuitry uses the same mechanisms as a means of creating useful perceptions and behaviors without information about the real world.

  11. A screen for fast evolving genes from Drosophila.

    PubMed

    Schmid, K J; Tautz, D

    1997-09-01

    In an attempt to quantify the rates of protein sequence divergence in Drosophila, we have devised a screen to differentiate between slow and fast evolving genes. We find that over one-third of randomly drawn cDNAs from a Drosophila melanogaster library do not cross-hybridize with Drosophila virilis DNA, indicating that they evolve with a very high rate. To determine the evolutionary characteristics of such protein sequences, we sequenced their homologs from a more closely related species (Drosophila yakuba). The amino acid substitution rates among these cDNAs are among the fastest known and several are only about 2-fold lower than the corresponding values for silent substitutions. An analysis of within-species polymorphisms for one of these sequences reveals an exceptionally high number of polymorphic amino acid positions, indicating that the protein is not under strong negative selection. We conclude that the Drosophila genome harbors a substantial proportion of genes with a very high divergence rate.

  12. Evolvable Production Systems: Mechatronic Production Equipment with Evolutionary Control

    NASA Astrophysics Data System (ADS)

    Maffei, Antonio; Onori, Mauro; Neves, Pedro; Barata, José

    Current major roadmapping efforts have all clearly underlined that true industrial sustainability will require far higher levels of systems' autonomy and adaptability. In accordance with these recommendations, the Evolvable Production Systems (EPS) has aimed at developing such technological solutions and support mechanisms. Since its inception in 2002 as a next generation of production systems, the concept is being further developed and tested to emerge as a production system paradigm. Characteristically, Evolvable systems have distributed control, and are composed of intelligent modules with embedded control. A concerted effort is being exerted through European research projects in collaboration with manufacturers, technology/equipment suppliers, and universities. After introducing EPS, this paper presents current developments and applications.

  13. The origins of religion: evolved adaptation or by-product?

    PubMed

    Pyysiäinen, Ilkka; Hauser, Marc

    2010-03-01

    Considerable debate has surrounded the question of the origins and evolution of religion. One proposal views religion as an adaptation for cooperation, whereas an alternative proposal views religion as a by-product of evolved, non-religious, cognitive functions. We critically evaluate each approach, explore the link between religion and morality in particular, and argue that recent empirical work in moral psychology provides stronger support for the by-product approach. Specifically, despite differences in religious background, individuals show no difference in the pattern of their moral judgments for unfamiliar moral scenarios. These findings suggest that religion evolved from pre-existing cognitive functions, but that it may then have been subject to selection, creating an adaptively designed system for solving the problem of cooperation.

  14. Properties of artificial networks evolved to contend with natural spectra.

    PubMed

    Morgenstern, Yaniv; Rostami, Mohammad; Purves, Dale

    2014-07-22

    Understanding why spectra that are physically the same appear different in different contexts (color contrast), whereas spectra that are physically different appear similar (color constancy) presents a major challenge in vision research. Here, we show that the responses of biologically inspired neural networks evolved on the basis of accumulated experience with spectral stimuli automatically generate contrast and constancy. The results imply that these phenomena are signatures of a strategy that biological vision uses to circumvent the inverse optics problem as it pertains to light spectra, and that double-opponent neurons in early-level vision evolve to serve this purpose. This strategy provides a way of understanding the peculiar relationship between the objective world and subjective color experience, as well as rationalizing the relevant visual circuitry without invoking feature detection or image representation.

  15. Herschel-SPIRE FTS Spectroscopy of Evolved Stars

    NASA Astrophysics Data System (ADS)

    Wesson, R.; Cernicharo, J.; Barlow, M. J.; Matsuura, M.; Decin, L.; Groenewegen, M. A. T.; Polehampton, E. T.; Agundez, M.; Cohen, M.; Daniel, F.; Exter, K. M.; Gear, W. K.; Gomez, H. L.; Hargrave, P. C.; Imhof, P.; Ivison, R. J.; Leeks, S. J.; Lim, T. L.; Olofsson, G.; Savini, G.; Sibthorpe, B.; Swinyard, B. M.; Ueta, T.; Witherick, D. K.; Yates, J. A.

    2011-09-01

    We present far-infrared and submillimetre spectra of evolved objects observed with the SPIRE Fourier-transform spectrometer on board the Herschel Space Observatory. The observations cover wavelengths 195-670 μm, a region of the electromagnetic spectrum hitherto difficult to study. The far-infrared spectra of these objects are rich and complex. We determine physical conditions from observations of the rotational lines of several molecules, and present initial large velocity gradient models for AFGL 618. We detect water in AFGL 2688 for the first time, and confirm its presence in AFGL 618 in both ortho and para forms. In addition, we detect of the J = 1-0 line of CH+ in NGC 7027. Finally, we present new Herschel-SPIRE spectroscopic observations of both O-rich and C-rich evolved sources, and discuss preliminary investigations into their physical conditions.

  16. Evolving Approaches to Patients with Advanced Differentiated Thyroid Cancer

    PubMed Central

    Sherman, Steven I.

    2013-01-01

    Advanced differentiated thyroid cancer (DTC), defined by clinical characteristics including gross extrathyroidal invasion, distant metastases, radioiodine (RAI) resistance, and avidity for 18-fluorodeoxyglucose (positron emission tomography-positive), is found in approximately 10–20% of patients with DTC. Standard therapy (surgery, RAI, TSH suppression with levothyroxine) is ineffective for many of these patients, as is standard chemotherapy. Our understanding of the molecular mechanisms leading to DTC and the transformation to advanced DTC has rapidly evolved over the past 15–20 years. Newer targeted therapy, specifically inhibitors of intracellular kinase signaling pathways, and cooperative multicenter clinical trials have dramatically changed the therapeutic landscape for patients with advanced DTC. In this review focusing on morbidities, molecules, and medicinals, we present a patient with advanced DTC, explore the genetics and molecular biology of advanced DTC, and review evolving therapies for these patients including multikinase inhibitors, selective kinase inhibitors, and combination therapies. PMID:23575762

  17. Enlightenment from a small but rapidly evolving penetrating aortic ulcer.

    PubMed

    Tan, Guangyi; Tang, Wenyi; Chen, Jian

    2016-07-01

    Penetrating aortic ulcer (PAU) is a pathologic type of acute aortic syndrome and usually locates in the descending aorta. The presentation, behavior and natural history of this disease process have not been clear. Here we report a case in which a rapidly evolving PAU in descending aorta needed aggressive percutaneous interventional treatment. The present case with its unique scenario might draw clinicians' attention on a "beyond the guidelines" issue.

  18. Modeling and control of evolving, noisy chaotic dynamical systems

    NASA Astrophysics Data System (ADS)

    Weber, Nicholas Noel

    We study the modeling and control of evolving dynamical systems. In particular we model the dynamics of an evolving noisy iterative map, we study the extraction of the control parameter of the same map using a sparse time series from it, and we also study the dynamics of an evolving electronic circuit whose control parameter changes in proportion to low-pass filtering of one of its dynamical variables. First, we study a noisy one-dimensional iterative map whose system parameter evolves randomly in time. We find that there is an optimal number of model parameters and that there is an optimal number of data points to be retained as input for the model. Second, we study modeling based on a sparsely sampled time series. We compare three different methods of extracting the system parameter from a sparse set of the map's data. Two of these methods employ an ensemble of test trajectories in order to determine if statistical properties, such as the law of large numbers, facilitate the search for the system parameter. The third extraction method uses a single test trajectory. Third, we study self-adjusting dynamical systems. We study the logistic map and a chaotic electronic circuit, the Chua oscillator. We find that when these systems begin in a chaotic region of phase space, they self-adjust their own dynamics to the edge of chaos or a periodic window neighboring chaos. In addition, we study a self-adjusting system which has both low-pass filtered feedback and linear feedback control applied to its system parameter. The objective of the linear feedback control component is to drive the parameter to a target value in the presence of the low-pass component which behaves as described earlier. We find that the system parameter stays close to the target parameter value if the dynamics is non-chaotic. (Abstract shortened by UMI.)

  19. Computational structural mechanics methods research using an evolving framework

    NASA Technical Reports Server (NTRS)

    Knight, N. F., Jr.; Lotts, C. G.; Gillian, R. E.

    1990-01-01

    Advanced structural analysis and computational methods that exploit high-performance computers are being developed in a computational structural mechanics research activity sponsored by the NASA Langley Research Center. These new methods are developed in an evolving framework and applied to representative complex structural analysis problems from the aerospace industry. An overview of the methods development environment is presented, and methods research areas are described. Selected application studies are also summarized.

  20. Conflict resolution strategies: when ethical dilemmas evolve into conflict.

    PubMed

    Broom, C

    1991-01-01

    In critical care, ethical dilemmas arise when all duties, rights, and goals cannot be satisfied by the alternatives that are available. Conflicts evolve from ethical dilemmas due to differences in how nurses, physicians, administrators, and patients or families who are involved in a clinical situation assign priorities or interpret roles and responsibilities. This author presents strategies for critical care nurses to use to resolve conflicts that arise in relation to ethical dilemmas.

  1. Spatial mobility in India: evolving patterns, emerging issues and implications.

    PubMed

    Mehta, S

    1990-01-01

    "This study examines the patterns of spatial mobility in India as expressed at the inter-state level for the post-Independence period. Comparing these patterns with those which had been evolving throughout the colonial period the paper probes into the processes of dislocation of people in the context of India's development strategy.... The analysis points out the complex interrelationships with the nature of socio-economic development and suggests alternatives for stemming distress migration from the backward regions."

  2. Hemicrania continua evolving from cluster headache responsive to valproic acid.

    PubMed

    Lambru, Giorgio; Castellini, Paola; Bini, Annamaria; Evangelista, Andrea; Manzoni, Gian Camillo; Torelli, Paola

    2008-10-01

    Hemicrania continua (HC) is a rare type of primary headache characterized by a prompt and enduring response to indomethacin. We describe a patient who suffered from cluster headache evolving into ipsilateral HC, who does not tolerate a long-term indomethacin therapy. The case was complex in terms of diagnosis, associated comorbidity, and choice of treatment; after several trials with different therapeutic regimens, we started the patient on a therapy with valproic acid and obtained an improvement of her HC.

  3. Enlightenment from a small but rapidly evolving penetrating aortic ulcer.

    PubMed

    Tan, Guangyi; Tang, Wenyi; Chen, Jian

    2016-07-01

    Penetrating aortic ulcer (PAU) is a pathologic type of acute aortic syndrome and usually locates in the descending aorta. The presentation, behavior and natural history of this disease process have not been clear. Here we report a case in which a rapidly evolving PAU in descending aorta needed aggressive percutaneous interventional treatment. The present case with its unique scenario might draw clinicians' attention on a "beyond the guidelines" issue. PMID:26961076

  4. Evolving with Medicare: an approach to retirement strategy.

    PubMed

    Habliston, Charles; Hanrahan, Mark

    2006-01-01

    With Medicare Part D now providing prescription drug coverage, employers' retiree health plans are ripe for change. Effective change requires more than just adjustments. A global or enterprisewide approach to the development of a retirement strategy is important and should encompass five components: design, finance, administration, communication and control. This article discusses the strategic approach to crafting retiree health policy as the Medicare landscape continues to evolve. PMID:17039820

  5. The Evolving Nature of Hepatic Abscess: A Review

    PubMed Central

    Mavilia, Marianna G.; Molina, Marco; Wu, George Y.

    2016-01-01

    Abstract Hepatic abscess (HA) remains a serious and often difficult to diagnose problem. HAs can be divided into three main categories based on the underlying conditions: infectious, malignant, and iatrogenic. Infectious abscesses include those secondary to direct extension from local infection, systemic bacteremia, and intra-abdominal infections that seed the portal system. However, over the years, the etiologies and risks factors for HA have continued to evolve. Prompt recognition is important for instituting effective management and obtaining good outcomes. PMID:27350946

  6. The evolving state of online search for consumer health information.

    PubMed

    Hunscher, Dale A

    2008-11-06

    Online search for consumer health information is a public health concern. General-purpose search engines have historically returned health-related query results of dubious relevance and quality. Meanwhile, consumers have become increasingly reliant on and trusting of these engines. General-purpose search engines have attempted to make their interfaces more consumer-friendly with respect to consumer health queries and their results more relevant and trustworthy. We illustrate the characteristics of the evolving health search landscape using network visualization.

  7. Cooperative behavior and phase transitions in co-evolving stag hunt game

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Li, Y. S.; Xu, C.; Hui, P. M.

    2016-02-01

    Cooperative behavior and different phases in a co-evolving network dynamics based on the stag hunt game is studied. The dynamical processes are parameterized by a payoff r that tends to promote non-cooperative behavior and a probability q for a rewiring attempt that could isolate the non-cooperators. The interplay between the parameters leads to different phases. Detailed simulations and a mean field theory are employed to reveal the properties of different phases. For small r, the cooperators are the majority and form a connected cluster while the non-cooperators increase with q but remain isolated over the whole range of q, and it is a static phase. For sufficiently large r, cooperators disappear in an intermediate range qL ≤ q ≤qU and a dynamical all-non-cooperators phase results. For q >qU, a static phase results again. A mean field theory based on how the link densities change in time by the co-evolving dynamics is constructed. The theory gives a phase diagram in the q- r parameter space that is qualitatively in agreement with simulation results. The sources of discrepancies between theory and simulations are discussed.

  8. Detecting the Collapse of Cooperation in Evolving Networks.

    PubMed

    Cavaliere, Matteo; Yang, Guoli; Danos, Vincent; Dakos, Vasilis

    2016-01-01

    The sustainability of biological, social, economic and ecological communities is often determined by the outcome of social conflicts between cooperative and selfish individuals (cheaters). Cheaters avoid the cost of contributing to the community and can occasionally spread in the population leading to the complete collapse of cooperation. Although such collapse often unfolds unexpectedly, it is unclear whether one can detect the risk of cheater's invasions and loss of cooperation in an evolving community. Here, we combine dynamical networks and evolutionary game theory to study the abrupt loss of cooperation with tools for studying critical transitions. We estimate the risk of cooperation collapse following the introduction of a single cheater under gradually changing conditions. We observe an increase in the average time it takes for cheaters to be eliminated from the community as the risk of collapse increases. We argue that such slow system response resembles slowing down in recovery rates prior to a critical transition. In addition, we show how changes in community structure reflect the risk of cooperation collapse. We find that these changes strongly depend on the mechanism that governs how cheaters evolve in the community. Our results highlight novel directions for detecting abrupt transitions in evolving networks. PMID:27492876

  9. Evolving experience-dependent robust behaviour in embodied agents.

    PubMed

    Fernandez-Leon, Jose A

    2011-01-01

    In this work, based on behavioural and dynamical evidence, a study of simulated agents with the capacity to change feedback from their bodies to accomplish a one-legged walking task is proposed to understand the emergence of coupled dynamics for robust behaviour. Agents evolve with evolutionary-defined biases that modify incoming body signals (sensory offsets). Analyses on whether these agents show further dependence to their environmental coupled dynamics than others with no feedback control is described in this article. The ability to sustain behaviours is tested during lifetime experiments with mutational and sensory perturbations after evolution. Using dynamical systems analysis, this work identifies conditions for the emergence of dynamical mechanisms that remain functional despite sensory perturbations. Results indicate that evolved agents with evolvable sensory offset depends not only on where in neural space the state of the neural system operates, but also on the transients to which the inner-system was being driven by sensory signals from its interactions with the environment, controller, and agent body. Experimental evidence here leads discussions on a dynamical systems perspective on behavioural robustness that goes beyond attractors of controller phase space.

  10. THE DECELERATION OF NEBULAR SHELLS IN EVOLVED PLANETARY NEBULAE

    SciTech Connect

    Pereyra, Margarita; Richer, Michael G.; Lopez, Jose Alberto E-mail: richer@astrosen.unam.mx

    2013-07-10

    We have selected a group of 100 evolved planetary nebulae (PNe) and study their kinematics based upon spatially-resolved, long-slit, echelle spectroscopy. The data have been drawn from the San Pedro Martir Kinematic Catalogue of PNe. The aim is to characterize in detail the global kinematics of PNe at advanced stages of evolution with the largest sample of homogenous data used to date for this purpose. The results reveal two groups that share kinematics, morphology, and photo-ionization characteristics of the nebular shell and central star luminosities at the different late stages under study. The typical flow velocities we measure are usually larger than seen in earlier evolutionary stages, with the largest velocities occurring in objects with very weak or absent [N II] {lambda}6584 line emission, by all indications the least evolved objects in our sample. The most evolved objects expand more slowly. This apparent deceleration during the final stage of PNe evolution is predicted by hydrodynamical models, but other explanations are also possible. These results provide a template for comparison with the predictions of theoretical models.

  11. Angular momentum transport via internal gravity waves in evolving stars

    SciTech Connect

    Fuller, Jim; Lecoanet, Daniel; Cantiello, Matteo; Brown, Ben

    2014-11-20

    Recent asteroseismic advances have allowed for direct measurements of the internal rotation rates of many subgiant and red giant stars. Unlike the nearly rigidly rotating Sun, these evolved stars contain radiative cores that spin faster than their overlying convective envelopes, but slower than they would in the absence of internal angular momentum transport. We investigate the role of internal gravity waves in angular momentum transport in evolving low-mass stars. In agreement with previous results, we find that convectively excited gravity waves can prevent the development of strong differential rotation in the radiative cores of Sun-like stars. As stars evolve into subgiants, however, low-frequency gravity waves become strongly attenuated and cannot propagate below the hydrogen-burning shell, allowing the spin of the core to decouple from the convective envelope. This decoupling occurs at the base of the subgiant branch when stars have surface temperatures of T ≈ 5500 K. However, gravity waves can still spin down the upper radiative region, implying that the observed differential rotation is likely confined to the deep core near the hydrogen-burning shell. The torque on the upper radiative region may also prevent the core from accreting high angular momentum material and slow the rate of core spin-up. The observed spin-down of cores on the red giant branch cannot be totally attributed to gravity waves, but the waves may enhance shear within the radiative region and thus increase the efficacy of viscous/magnetic torques.

  12. Emergent diversity in an open-ended evolving virtual community.

    PubMed

    Fernández, Jose D; Lobo, Daniel; Martín, Gema M; Doursat, René; Vico, Francisco J

    2012-01-01

    Understanding the dynamics of biodiversity has become an important line of research in theoretical ecology and, in particular, conservation biology. However, studying the evolution of ecological communities under traditional modeling approaches based on differential calculus requires species' characteristics to be predefined, which limits the generality of the results. An alternative but less standardized methodology relies on intensive computer simulation of evolving communities made of simple, explicitly described individuals. We study here the formation, evolution, and diversity dynamics of a community of virtual plants with a novel individual-centered model involving three different scales: the genetic, the developmental, and the physiological scales. It constitutes an original attempt at combining development, evolution, and population dynamics (based on multi-agent interactions) into one comprehensive, yet simple model. In this world, we observe that our simulated plants evolve increasingly elaborate canopies, which are capable of intercepting ever greater amounts of light. Generated morphologies vary from the simplest one-branch structure of promoter plants to a complex arborization of several hundred thousand branches in highly evolved variants. On the population scale, the heterogeneous spatial structuration of the plant community at each generation depends solely on the evolution of its component plants. Using this virtual data, the morphologies and the dynamics of diversity production were analyzed by various statistical methods, based on genotypic and phenotypic distance metrics. The results demonstrate that diversity can spontaneously emerge in a community of mutually interacting individuals under the influence of specific environmental conditions.

  13. Evolving proteins in mammalian cells using somatic hypermutation.

    PubMed

    Wang, Lei; Tsien, Roger Y

    2006-01-01

    We describe a new method to mutate target genes through somatic hypermutation (SHM) and to evolve proteins directly in living mammalian cells. Target genes are expressed under the control of an inducible promoter in a B-cell line that hypermutates its immunoglobulin (Ig) V genes constitutively. Mutations can be introduced into the target gene through SHM upon transcription. Mutant genes are then expressed and selected or screened for desired properties in cells. Identified cells are subjected to another round of mutation and selection or screening. This process can be iterated easily for numerous rounds, and multiple reinforcing mutations can be accumulated to produce desirable phenotypes. This approach bypasses labor-intensive in vitro mutagenesis and samples a large protein sequence space. In this protocol a monomeric red fluorescent protein (mRFP1.2) was evolved in Ramos cells to afford a mutant (mPlum) with far-red emission. This method can be adapted to evolve other eukaryotic proteins and to be used in other cells able to perform SHM. For each round of evolution, it takes approximately 1 d to mutate the target gene, approximately 0.5-1 d to select or screen, and 2-4 d to propagate the cells for the next round depending on how many cells are collected. PMID:17406421

  14. Differential Scanning Calorimetry and Evolved Gas Analysis of Hydromagnesite

    NASA Technical Reports Server (NTRS)

    Lauer, H. V., Jr.; Golden, D. C.; Ming, Douglas W.; Boynton, W. V.

    1999-01-01

    Volatile-bearing minerals (e.g., Fe-oxyhydroxides, phyllosilicates, carbonates and sulfates) may be important phases on the surface of Mars. In order to characterize these phases the Thermal and Evolved Gas Analyzer (TEGA) flying on the Mars'98 lander will perform analyses on surface samples from Mars. Hydromagnesite [Mg5(CO3)4(OH)2.4H2O] is considered a good standard mineral to examine as a Mars soil analog component because it evolves both H2O and CO2 at temperatures between 0 and 600 C. Our aim here is to interpret the DSC signature of hydromagnesite under ambient pressure and 20 sccm N2 flow in the range 25 to 600 C. The DSC curve for hydromagnesite under the above conditions consists of three endothermic peaks at temperatures 296, 426, and 548 and one sharp exotherm at 511 C. X-ray analysis of the sample at different stop temperatures suggested that the exotherm corresponded with the formation of crystalline magnesite. The first endotherm was due to dehydration of hydromagnesite, and then the second one was due to the decomposition of carbonate, immediately followed by the formation of magnesite (exotherm) and its decomposition to periclase (last endotherm). Evolution of water and CO2 were consistent with the observed enthalpy changes. A library of such DSC-evolved gas curves for putative Martian minerals are currently being acquired in order to facilitate the interpretation of results obtained by a robotic lander.

  15. Changes in bay circulation in an evolving multiple inlet system

    NASA Astrophysics Data System (ADS)

    Orescanin, Mara M.; Elgar, Steve; Raubenheimer, Britt

    2016-08-01

    Observations and numerical model (ADCIRC) simulations are used to quantify the changes in circulation within the evolving, shallow, two-inlet tidal Katama system, Martha's Vineyard, MA. From 2011 to 2013, Katama Inlet, connecting Katama Bay to the Atlantic, became 5 times longer, 1/3 as wide, and 1/3 as deep as the inlet migrated and rotated. This morphological evolution caused a significant loss of energy throughout Katama Bay and Edgartown Channel, which connects the bay to Vineyard Sound. The decrease in energy as the inlet evolved between 2011 and 2013 was not monotonic. Model simulations suggest bathymetric changes caused by Hurricane Irene (August 2011) resulted in a temporary increase in circulation energy throughout the inlets and bay. Changes in the M4 and M6 tidal constituents, harmonics of the primary M2 tidal forcing, suggest the changes in the observed circulation patterns primarily were owing to changes in friction, and not to changes in advection resulting from the evolving inlet location, orientation, or geometry, consistent with previous results.

  16. Do Brain Networks Evolve by Maximizing Their Information Flow Capacity?

    PubMed Central

    Antonopoulos, Chris G.; Srivastava, Shambhavi; Pinto, Sandro E. de S.; Baptista, Murilo S.

    2015-01-01

    We propose a working hypothesis supported by numerical simulations that brain networks evolve based on the principle of the maximization of their internal information flow capacity. We find that synchronous behavior and capacity of information flow of the evolved networks reproduce well the same behaviors observed in the brain dynamical networks of Caenorhabditis elegans and humans, networks of Hindmarsh-Rose neurons with graphs given by these brain networks. We make a strong case to verify our hypothesis by showing that the neural networks with the closest graph distance to the brain networks of Caenorhabditis elegans and humans are the Hindmarsh-Rose neural networks evolved with coupling strengths that maximize information flow capacity. Surprisingly, we find that global neural synchronization levels decrease during brain evolution, reflecting on an underlying global no Hebbian-like evolution process, which is driven by no Hebbian-like learning behaviors for some of the clusters during evolution, and Hebbian-like learning rules for clusters where neurons increase their synchronization. PMID:26317592

  17. Evolving Human Alteration of the Carbon Cycle: the Watershed Continuum

    NASA Astrophysics Data System (ADS)

    Kaushal, S.; Delaney Newcomb, K.; Newcomer Johnson, T.; Pennino, M. J.; Smith, R. M.; Beaulieu, J. J.; Belt, K.; Grese, M.; Blomquist, J.; Duan, S.; Findlay, S.; Likens, G.; Mayer, P. M.; Murthy, S.; Utz, R.; Yepsen, M.

    2014-12-01

    Watersheds experiencing land development are constantly evolving, and their biogeochemical signatures are expected to evolve across both space and time in drainage waters. We investigate how land development influences spatial and temporal evolution of the carbon cycle from small streams to major rivers in the Eastern U.S. Along the watershed continuum, we show that there is spatial evolution in: (1) the amount, chemical form, and bioavailability of carbon; (2) carbon retention/release at the reach scale; and (3) ecosystem metabolism of carbon from headwaters to coastal waters. Over shorter time scales, the interaction between land use and climate variability alters magnitude and frequency of carbon "pulses" in watersheds. Amounts and forms of carbon pulses in agricultural and urban watersheds respond similarly to climate variability due to headwater alteration and loss of ecosystem services to buffer runoff and temperature changes. Over longer time scales, land use change has altered organic carbon concentrations in tidal waters of Chesapeake Bay, and there have been increased bicarbonate alkalinity concentrations in rivers throughout the Eastern U.S. due to human activities. In summary, our analyses indicates that the form and reactivity of carbon have evolved over space and time along the watershed continuum with major implications for downstream ecosystem metabolism, biological oxygen demand, carbon dioxide production, and river alkalinization.

  18. Social networks: Evolving graphs with memory dependent edges

    NASA Astrophysics Data System (ADS)

    Grindrod, Peter; Parsons, Mark

    2011-10-01

    The plethora of digital communication technologies, and their mass take up, has resulted in a wealth of interest in social network data collection and analysis in recent years. Within many such networks the interactions are transient: thus those networks evolve over time. In this paper we introduce a class of models for such networks using evolving graphs with memory dependent edges, which may appear and disappear according to their recent history. We consider time discrete and time continuous variants of the model. We consider the long term asymptotic behaviour as a function of parameters controlling the memory dependence. In particular we show that such networks may continue evolving forever, or else may quench and become static (containing immortal and/or extinct edges). This depends on the existence or otherwise of certain infinite products and series involving age dependent model parameters. We show how to differentiate between the alternatives based on a finite set of observations. To test these ideas we show how model parameters may be calibrated based on limited samples of time dependent data, and we apply these concepts to three real networks: summary data on mobile phone use from a developing region; online social-business network data from China; and disaggregated mobile phone communications data from a reality mining experiment in the US. In each case we show that there is evidence for memory dependent dynamics, such as that embodied within the class of models proposed here.

  19. Detecting the Collapse of Cooperation in Evolving Networks

    PubMed Central

    Cavaliere, Matteo; Yang, Guoli; Danos, Vincent; Dakos, Vasilis

    2016-01-01

    The sustainability of biological, social, economic and ecological communities is often determined by the outcome of social conflicts between cooperative and selfish individuals (cheaters). Cheaters avoid the cost of contributing to the community and can occasionally spread in the population leading to the complete collapse of cooperation. Although such collapse often unfolds unexpectedly, it is unclear whether one can detect the risk of cheater’s invasions and loss of cooperation in an evolving community. Here, we combine dynamical networks and evolutionary game theory to study the abrupt loss of cooperation with tools for studying critical transitions. We estimate the risk of cooperation collapse following the introduction of a single cheater under gradually changing conditions. We observe an increase in the average time it takes for cheaters to be eliminated from the community as the risk of collapse increases. We argue that such slow system response resembles slowing down in recovery rates prior to a critical transition. In addition, we show how changes in community structure reflect the risk of cooperation collapse. We find that these changes strongly depend on the mechanism that governs how cheaters evolve in the community. Our results highlight novel directions for detecting abrupt transitions in evolving networks. PMID:27492876

  20. A catalog of rotational and radial velocities for evolved stars

    NASA Astrophysics Data System (ADS)

    de Medeiros, J. R.; Mayor, M.

    1999-11-01

    Rotational and radial velocities have been measured for about 2000 evolved stars of luminosity classes IV, III, II and Ib covering the spectral region F, G and K. The survey was carried out with the CORAVEL spectrometer. The precision for the radial velocities is better than 0.30 km s-1, whereas for the rotational velocity measurements the uncertainties are typically 1.0 km s-1 for subgiants and giants and 2.0 km s-1 for class II giants and Ib supergiants. These data will add constraints to studies of the rotational behaviour of evolved stars as well as solid informations concerning the presence of external rotational brakes, tidal interactions in evolved binary systems and on the link between rotation, chemical abundance and stellar activity. In this paper we present the rotational velocity v sin i and the mean radial velocity for the stars of luminosity classes IV, III and II. Based on observations collected at the Haute--Provence Observatory, Saint--Michel, France and at the European Southern Observatory, La Silla, Chile. Table \\ref{tab5} also available in electronic form at CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

  1. The transcriptomics of an experimentally evolved plant-virus interaction

    PubMed Central

    Hillung, Julia; García-García, Francisco; Dopazo, Joaquín; Cuevas, José M.; Elena, Santiago F.

    2016-01-01

    Models of plant-virus interaction assume that the ability of a virus to infect a host genotype depends on the matching between virulence and resistance genes. Recently, we evolved tobacco etch potyvirus (TEV) lineages on different ecotypes of Arabidopsis thaliana, and found that some ecotypes selected for specialist viruses whereas others selected for generalists. Here we sought to evaluate the transcriptomic basis of such relationships. We have characterized the transcriptomic responses of five ecotypes infected with the ancestral and evolved viruses. Genes and functional categories differentially expressed by plants infected with local TEV isolates were identified, showing heterogeneous responses among ecotypes, although significant parallelism existed among lineages evolved in the same ecotype. Although genes involved in immune responses were altered upon infection, other functional groups were also pervasively over-represented, suggesting that plant resistance genes were not the only drivers of viral adaptation. Finally, the transcriptomic consequences of infection with the generalist and specialist lineages were compared. Whilst the generalist induced very similar perturbations in the transcriptomes of the different ecotypes, the perturbations induced by the specialist were divergent. Plant defense mechanisms were activated when the infecting virus was specialist but they were down-regulated when infecting with generalist. PMID:27113435

  2. Numerical method for evolving the dipolar projected Gross-Pitaevskii equation

    NASA Astrophysics Data System (ADS)

    Blakie, P. B.; Ticknor, C.; Bradley, A. S.; Martin, A. M.; Davis, M. J.; Kawaguchi, Y.

    2009-07-01

    We describe a method for evolving the projected Gross-Pitaevskii equation (PGPE) for an interacting Bose gas in a harmonic-oscillator potential, with the inclusion of a long-range dipolar interaction. The central difficulty in solving this equation is the requirement that the field is restricted to a small set of prescribed modes that constitute the low-energy c -field region of the system. We present a scheme, using a Hermite-polynomial-based spectral representation, which precisely implements this mode restriction and allows an efficient and accurate solution of the dipolar PGPE. We introduce a set of auxiliary oscillator states to perform a Fourier transform necessary to evaluate the dipolar interaction in reciprocal space. We extensively characterize the accuracy of our approach and derive Ehrenfest equations for the evolution of the angular momentum.

  3. Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyser (TEGA)

    NASA Technical Reports Server (NTRS)

    Musselwhite, D. S.; Boynton, W. V.; Ming, D. W.; Quadlander, G.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

    2000-01-01

    Differential Scanning Calorimetry (DSC) combined with evolved gas analysis (EGA) is a well developed technique for the analysis of a wide variety of sample types with broad application in material and soil sciences. However, the use of the technique for samples under conditions of pressure and temperature as found on other planets is one of current development and cutting edge research. The Thermal Evolved Gas Analyzer (TEGA), which was designed, built and tested at the University of Arizona's Lunar and Planetary Lab (LPL), utilizes DSC/EGA. TEGA, which was sent to Mars on the ill-fated Mars Polar Lander, was to be the first application of DSC/EGA on the surface of Mars as well as the first direct measurement of the volatile-bearing mineralogy in martian soil. Additional information is available in the original extended abstract.

  4. Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyzer (TEGA)

    NASA Technical Reports Server (NTRS)

    Musselwhite, D. S.; Boynton, W. V.; Ming, Douglas W.; Quadlander, G.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

    2000-01-01

    Differential Scanning Calorimetry (DSC) combined with evolved gas analysis (EGA) is a well developed technique for the analysis of a wide variety of sample types with broad application in material and soil sciences. However, the use of the technique for samples under conditions of pressure and temperature as found on other planets is one of current C development and cutting edge research. The Thermal Evolved Gas Analyzer (MGA), which was designed, built and tested at the University of Arizona's Lunar and Planetary Lab (LPL), utilizes DSC/EGA. TEGA, which was sent to Mars on the ill-fated Mars Polar Lander, was to be the first application of DSC/EGA on the surface of Mars as well as the first direct measurement of the volatile-bearing mineralogy in martian soil.

  5. Mapping the evolving strain field during continental breakup from crustal anisotropy in the Afar Depression

    PubMed Central

    Keir, Derek; Belachew, M.; Ebinger, C.J.; Kendall, J.-M.; Hammond, J.O.S.; Stuart, G.W.; Ayele, A.; Rowland, J.V.

    2011-01-01

    Rifting of the continents leading to plate rupture occurs by a combination of mechanical deformation and magma intrusion, yet the spatial and temporal scales over which these alternate mechanisms localize extensional strain remain controversial. Here we quantify anisotropy of the upper crust across the volcanically active Afar Triple Junction using shear-wave splitting from local earthquakes to evaluate the distribution and orientation of strain in a region of continental breakup. The pattern of S-wave splitting in Afar is best explained by anisotropy from deformation-related structures, with the dramatic change in splitting parameters into the rift axis from the increased density of dyke-induced faulting combined with a contribution from oriented melt pockets near volcanic centres. The lack of rift-perpendicular anisotropy in the lithosphere, and corroborating geoscientific evidence of extension dominated by dyking, provide strong evidence that magma intrusion achieves the majority of plate opening in this zone of incipient plate rupture. PMID:21505441

  6. Dominant Inheritance of Field-Evolved Resistance to Bt Corn in Busseolafusca

    PubMed Central

    Campagne, Pascal; Kruger, Marlene; Pasquet, Rémy; Le Ru, Bruno; Van den Berg, Johnnie

    2013-01-01

    Transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been adopted worldwide, notably in developing countries. In spite of their success in controlling target pests while allowing a substantial reduction of insecticide use, the sustainable control of these pest populations is threatened by the evolution of resistance. The implementation of the “high dose/refuge” strategy for managing insect resistance in transgenic crops aims at delaying the evolution of resistance to Bt crops in pest populations by promoting survival of susceptible insects. However, a crucial condition for the “high dose/refuge” strategy to be efficient is that the inheritance of resistance should be functionally recessive. Busseolafusca developed high levels of resistance to the Bt toxin Cry 1Ab expressed in Bt corn in South Africa. To test whether the inheritance of B. fusca resistance to the Bt toxin could be considered recessive we performed controlled crosses with this pest and evaluated its survival on Bt and non-Bt corn. Results show that resistance of B. fusca to Bt corn is dominant, which refutes the hypothesis of recessive inheritance. Survival on Bt corn was not lower than on non-Bt corn for both resistant larvae and the F1 progeny from resistant × susceptible parents. Hence, resistance management strategies of B. fusca to Bt corn must address non-recessive resistance. PMID:23844262

  7. The evolving field of imaging mass spectrometry and its impact on future biological research

    PubMed Central

    Watrous, Jeramie D.; Alexandrov, Theodore; Dorrestein, Pieter C.

    2012-01-01

    Within the past decade, imaging mass spectrometry has been increasingly recognized as an indispensable technique for studying biological systems. Its rapid evolution has resulted in an impressive array of instrument variations and sample applications, yet the tools and data are largely confined to specialists. It is therefore important that at this junction the IMS community begin to establish IMS as a permanent fixture in life sciences research thereby making the technology and/or the data approachable by non-mass spectrometrists, leading to further integration into biological and clinical research. In this perspective article, we provide insight into the evolution and current state of imaging mass spectrometry and propose some of the directions that IMS could develop in order to stay on course to become one of the most promising new tools in life science research. PMID:21322093

  8. Feedback regulation of telomerase reverse transcriptase: new insight into the evolving field of telomerase in cancer.

    PubMed

    Wu, Xiao-Qin; Huang, Cheng; He, Xu; Tian, Yuan-Yao; Zhou, De-Xi; He, Yong; Liu, Xin-Hua; Li, Jun

    2013-12-01

    Telomerase reverse transcriptase (TERT) is the catalytic component of telomerase, especially the rate-limiting determinant of telomerase activity. So far, TERT has been reported to be over-expressed in more than 90% of cancers, thereby playing a critical role in sustained proliferation and survival potentials of various cancer cells. Over the past decade, a comprehensive network of transcription factors has been shown to be involved in the regulation of TERT. Furthermore, accumulating evidence has suggested that TERT could modulate the expression of numerous genes involved in diverse group of cellular processes, including cell cycle regulation and cellular signaling. Therefore, it indicates that TERT is both an effector and a regulator in carcinoma. However, the mechanisms of the interaction between TERT and its target genes are still not fully understood. Thus, it is necessary to consolidate and summarize recent developments of the cross-talk between TERT and related genes in cancer cells or other cells with cancer cell characteristics, and elucidate these relevant mechanisms. In this review, we focus on various signaling pathways and genes that participate in the feedback regulation of TERT and the underlying feedback loop mechanism of TERT, further providing new insights into non-telomeric functions of telomerase and potentially to be used as a novel therapeutic target for cancer. PMID:23993966

  9. Control of canalization and evolvability by Hsp90.

    PubMed

    Milton, Claire C; Ulane, Christina M; Rutherford, Suzannah

    2006-01-01

    Partial reduction of Hsp90 increases expression of morphological novelty in qualitative traits of Drosophila and Arabidopsis, but the extent to which the Hsp90 chaperone also controls smaller and more likely adaptive changes in natural quantitative traits has been unclear. To determine the effect of Hsp90 on quantitative trait variability we deconstructed genetic, stochastic and environmental components of variation in Drosophila wing and bristle traits of genetically matched flies, differing only by Hsp90 loss-of-function or wild-type alleles. Unexpectedly, Hsp90 buffering was remarkably specific to certain normally invariant and highly discrete quantitative traits. Like the qualitative trait phenotypes controlled by Hsp90, highly discrete quantitative traits such as scutellor and thoracic bristle number are threshold traits. When tested across genotypes sampled from a wild population or in laboratory strains, the sensitivity of these traits to many types of variation was coordinately controlled, while continuously variable bristle types and wing size, and critically invariant left-right wing asymmetry, remained relatively unaffected. Although increased environmental variation and developmental noise would impede many types of selection response, in replicate populations in which Hsp90 was specifically impaired, heritability and 'extrinsic evolvability', the expected response to selection, were also markedly increased. However, despite the overall buffering effect of Hsp90 on variation in populations, for any particular individual or genotype in which Hsp90 was impaired, the size and direction of its effects were unpredictable. The trait and genetic-background dependence of Hsp90 effects and its remarkable bias toward invariant or canalized traits support the idea that traits evolve independent and trait-specific mechanisms of canalization and evolvability through their evolution of non-linearity and thresholds. Highly non-linear responses would buffer variation

  10. Rapidly evolving Rab GTPase paralogs and reproductive isolation in Drosophila.

    PubMed

    Hutter, Pierre

    2007-01-01

    Alterations at the X-linked Hmr gene of Drosophila melanogaster can fully restore viability and partially restore fertility in hybrid flies from crosses between D. melanogaster and any of its three most closely related species. Although more than one gene is expected to be involved in these barriers to reproduction, a single DNA-binding protein was recently identified as HMR. The Hmr gene was shown to evolve unusually fast, a feature that supports its role in causing genetic incompatibility in a hybrid genotype. The current treatment of hybrid genetics focuses not only on Hmr but also on the Rab9D gene, which lies only 1kb from Hmr. Rab9D is proposed also to influence hybrid viability. This gene has remained tightly linked to Hmr for about 10 million years, but it has diverged even more than Hmr with regard to D. melanogaster and its most closely related species. Furthermore, the 197-amino acid RAB9D protein contains four amino acid substitutions in the D. melanogaster-rescuing mutant Hmr1. Rab9D is shown to have evolved under very strong positive selection and to be the most recent member of a cluster of six paralogs that encode small RAB GTPases. Four of the six paralogs are unique to D. melanogaster in which they have diverged considerably, their encoded proteins sharing less than 50% amino acid identities with proteins from their orthologs in the closest species. Only two Rab orthologs are present in these sibling species and none is present in the genomes of more distantly related Drosophila species. Rapidly evolving Rab paralogs near the Hmr locus probably developed functional specialization of redundant proteins involved in trafficking macromolecules between cytoplasm and nucleus. Positive selection acting on duplicates of these Rab genes appears to participate in reproductive isolation.

  11. EVOLVE 4.0 orbital debris mitigation studies

    NASA Astrophysics Data System (ADS)

    Krisko, P. H.; Johnson, N. L.; Opiela, J. N.

    2001-01-01

    In a continuing effort to limit future space debris generation, the NASA Policy Directive 8710.3 was issued in May 1997. It requires all NASA-sponsored programs to conduct formal assessments in accordance with NASA Safety Standard 1740.14 to quantify the potential to generate debris and to consider debris mitigation options. Recent improvements to the NASA long-term debris environment model, EVOLVE 4.0, allow for a reassessment of the effects of NASA Safety Standard mitigation measures on the projected debris environment. The NASA Safety Standard guidelines requiring the passivation of upper stages and spacecraft through depletion of on-board energy sources, and the post-mission disposal of satellites may be studied with EVOLVE 4.0. In this paper, we present the results of a set of parametric EVOLVE 4.0 studies. We set our test matrix to include a draconian level of explosion suppression, i.e., passivation in future launches, and post-mission disposal decay time periods ranging from 100 years to 25 years. The post-mission disposal options are initiated at a time 10 years in the future. It is confirmed that explosion suppression alone effects only a minor change in the long-term environment. Post-mission disposal implementation is required to significantly reduce it. But complications arise for the longer tested post-mission disposal lifetime. The enhanced dwell time at low altitudes (the dominant manned spacecraft region of Earth orbits) increases the likelihood that a collision will occur there compared to the lower post-mission disposal lifetime of 25 years.

  12. NASA's new breakup model of evolve 4.0

    NASA Astrophysics Data System (ADS)

    Johnson, N. L.; Krisko, P. H.; Liou, J.-C.; Anz-Meador, P. D.

    2001-01-01

    Analyses of the fragmentation (due to explosions and collisions) of spacecraft and rocket bodies in low Earth orbit (LEO) have been performed this year at NASA/JSC. The overall goals of this study have been to achieve a better understanding of the results of fragmentations on the orbital debris environment and then to implement this understanding into the breakup model of EVOLVE 4.0. The previous breakup model implemented in EVOLVE 3.0 and other long-term orbital debris environment models was known to be inadequate in two major areas. First, it treated all fragmentational debris as spheres of a density which varied as a function of fragment diameter, where diameter was directly related to mass. Second, it underestimated the generation of fragments smaller than 10-cm in the majority of explosions. Without reliable data from both ground tests and on-orbit breakups, these inadequacies were unavoidable. Recent years, however, have brought additional data and related analyses: results of three ground tests, better on-orbit size and mass estimation techniques, more regular orbital tracking and reporting, additional radar resources dedicated to the observation of small objects, and simply a longer time period with which to observe the debris and their decay. Together these studies and data are applied to the reanalysis of the breakup model. In this paper we compare the new breakup model to the old breakup model in detail, including the size distributions for explosions and collisions, the area-to-mass and impact velocity assignments and distributions, and the delta-velocity distributions. These comparisons demonstrate a significantly better understanding of the fragmentation process as compared to previous versions of EVOLVE.

  13. Evolving networks-Using past structure to predict the future

    NASA Astrophysics Data System (ADS)

    Shang, Ke-ke; Yan, Wei-sheng; Small, Michael

    2016-08-01

    Many previous studies on link prediction have focused on using common neighbors to predict the existence of links between pairs of nodes. More broadly, research into the structural properties of evolving temporal networks and temporal link prediction methods have recently attracted increasing attention. In this study, for the first time, we examine the use of links between a pair of nodes to predict their common neighbors and analyze the relationship between the weight and the structure in static networks, evolving networks, and in the corresponding randomized networks. We propose both new unweighted and weighted prediction methods and use six kinds of real networks to test our algorithms. In unweighted networks, we find that if a pair of nodes connect to each other in the current network, they will have a higher probability to connect common nodes both in the current and the future networks-and the probability will decrease with the increase of the number of neighbors. Furthermore, we find that the original networks have their particular structure and statistical characteristics which benefit link prediction. In weighted networks, the prediction algorithm performance of networks which are dominated by human factors decrease with the decrease of weight and are in general better in static networks. Furthermore, we find that geographical position and link weight both have significant influence on the transport network. Moreover, the evolving financial network has the lowest predictability. In addition, we find that the structure of non-social networks has more robustness than social networks. The structure of engineering networks has both best predictability and also robustness.

  14. A Change Impact Analysis to Characterize Evolving Program Behaviors

    NASA Technical Reports Server (NTRS)

    Rungta, Neha Shyam; Person, Suzette; Branchaud, Joshua

    2012-01-01

    Change impact analysis techniques estimate the potential effects of changes made to software. Directed Incremental Symbolic Execution (DiSE) is an intraprocedural technique for characterizing the impact of software changes on program behaviors. DiSE first estimates the impact of the changes on the source code using program slicing techniques, and then uses the impact sets to guide symbolic execution to generate path conditions that characterize impacted program behaviors. DiSE, however, cannot reason about the flow of impact between methods and will fail to generate path conditions for certain impacted program behaviors. In this work, we present iDiSE, an extension to DiSE that performs an interprocedural analysis. iDiSE combines static and dynamic calling context information to efficiently generate impacted program behaviors across calling contexts. Information about impacted program behaviors is useful for testing, verification, and debugging of evolving programs. We present a case-study of our implementation of the iDiSE algorithm to demonstrate its efficiency at computing impacted program behaviors. Traditional notions of coverage are insufficient for characterizing the testing efforts used to validate evolving program behaviors because they do not take into account the impact of changes to the code. In this work we present novel definitions of impacted coverage metrics that are useful for evaluating the testing effort required to test evolving programs. We then describe how the notions of impacted coverage can be used to configure techniques such as DiSE and iDiSE in order to support regression testing related tasks. We also discuss how DiSE and iDiSE can be configured for debugging finding the root cause of errors introduced by changes made to the code. In our empirical evaluation we demonstrate that the configurations of DiSE and iDiSE can be used to support various software maintenance tasks

  15. Formation of Magnesium Silicates is Limited around Evolved Stars

    NASA Astrophysics Data System (ADS)

    Kimura, Yuki; Nuth, J. A., III

    2009-05-01

    Laboratory experiments suggest that magnesium silicide (Mg2Si) grains could be produced in the hydrogen dominant gas outflow from evolved stars in addition to amorphous oxide minerals. Astronomical observations have shown the existence of abundant silicate grains around evolved stars and we have long realized that most of the silicate grains are amorphous, based on the observed infrared features. Only high mass loss stars show the feature attributed to magnesium-rich crystalline silicate about 10-20 % respect to total silicates, so far. The lower degree of crystallinity observed in silicates formed in outflows of lower mass-loss-rate stars might be caused by the formation of magnesium silicide in this relatively hydrogen-rich environment. As a result of predominant distribution of magnesium into the silicide, the composition of interstellar amorphous silicates could be magnesium poor compared with silicon. Indeed, the chemical composition of isotopically anomalous GEMS (glass with embedded metal and sulfides) is magnesium poor with respect to a forsteritic composition (Floss et al. 2006; Keller & Messenger 2007). Infrared observations suggest that there is little or no crystalline forsterite in interstellar environments while there is an abundance of crystalline forsterite in our Solar System. If the forsterite is a result of the oxidation of interstellar magnesium silicide, then it is clear both why crystalline forsterite is stoichiometric olivine and why the chemical composition of isotopically anomalous GEMS is magnesium poor with respect to a forsteritic composition. In addition, it may also explain why the chemical composition of olivine is iron poor. Unfortunately, magnesium silicide has never been detected via astronomical observation or in the analysis of primitive meteorites. I would suggest that future analysis of meteorites and theoretical calculations could confirm the possibility of the formation of magnesium silicide grains around evolved stars.

  16. Evolving Multi Rover Systems in Dynamic and Noisy Environments

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan; Agogino, Adrian

    2005-01-01

    In this chapter, we address how to evolve control strategies for a collective: a set of entities that collectively strives to maximize a global evaluation function that rates the performance of the full system. Addressing such problems by directly applying a global evolutionary algorithm to a population of collectives is unworkable because the search space is prohibitively large. Instead, we focus on evolving control policies for each member of the collective, where each member is trying to maximize the fitness of its own population. The main difficulty with this approach is creating fitness evaluation functions for the members of the collective that induce the collective to achieve high performance with respect to the system level goal. To overcome this difficulty, we derive member evaluation functions that are both aligned with the global evaluation function (ensuring that members trying to achieve high fitness results in a collective with high fitness) and sensitive to the fitness of each member (a member's fitness depends more on its own actions than on actions of other members). In a difficult rover coordination problem in dynamic and noisy environments, we show how to construct evaluation functions that lead to good collective behavior. The control policy evolved using aligned and member-sensitive evaluations outperforms global evaluation methods by up to a factor of four. in addition we show that the collective continues to perform well in the presence of high noise levels and when the environment is highly dynamic. More notably, in the presence of a larger number of rovers or rovers with noisy sensors, the improvements due to the proposed method become significantly more pronounced.

  17. Emergence of complexity in evolving niche-model food webs.

    PubMed

    Guill, Christian; Drossel, Barbara

    2008-03-01

    We have analysed mechanisms that promote the emergence of complex structures in evolving model food webs. The niche model is used to determine predator-prey relationships. Complexity is measured by species richness as well as trophic level structure and link density. Adaptive dynamics that allow predators to concentrate on the prey species they are best adapted to lead to a strong increase in species number but have only a small effect on the number and relative occupancy of trophic levels. The density of active links also remains small but a high number of potential links allows the network to adjust to changes in the species composition (emergence and extinction of species). Incorporating effects of body size on individual metabolism leads to a more complex trophic level structure: both the maximum and the average trophic level increase. So does the density of active links. Taking body size effects into consideration does not have a measurable influence on species richness. If species are allowed to adjust their foraging behaviour, the complexity of the evolving networks can also be influenced by the size of the external resources. The larger the resources, the larger and more complex is the food web it can sustain. Body size effects and increasing resources do not change size and the simple structure of the evolving networks if adaptive foraging is prohibited. This leads to the conclusion that in the framework of the niche model adaptive foraging is a necessary but not sufficient condition for the emergence of complex networks. It is found that despite the stabilising effect of foraging adaptation the system displays elements of self-organised critical behaviour.

  18. Evolving excised black holes with TVD numerical methods

    NASA Astrophysics Data System (ADS)

    Neilsen, David

    2003-04-01

    Total Variation Diminishing (TVD) numerical methods have improved stability properties for nonlinear differential equations, and are widely used in computational fluid dynamics. While Einstein's equations are not genuinely nonlinear, these methods may be advantageous for solving the Einstein equations in specific instances, such as evolving fluid spacetimes and black holes with excision. Using a Frittelli-Reula formulation of the Einstein equations, I will present results of 1-D and 3-D black hole evolutions, and compare the performance of TVD methods with other numerical approaches.

  19. Hodge-Kodaira decomposition of evolving neural networks.

    PubMed

    Miura, Keiji; Aoki, Takaaki

    2015-02-01

    Although it is very important to scrutinize recurrent structures of neural networks for elucidating brain functions, conventional methods often have difficulty in characterizing global loops within a network systematically. Here we applied the Hodge-Kodaira decomposition, a topological method, to an evolving neural network model in order to characterize its loop structure. By controlling a learning rule parametrically, we found that a model with an STDP-rule, which tends to form paths coincident with causal firing orders, had the most loops. Furthermore, by counting the number of global loops in the network, we detected the inhomogeneity inside the chaotic region, which is usually considered intractable.

  20. The synthesis of organic and inorganic compounds in evolved stars.

    PubMed

    Kwok, Sun

    2004-08-26

    Recent isotopic analysis of meteorites and interplanetary dust has identified solid-state materials of pre-solar origin. We can now trace the origin of these inorganic grains to the circumstellar envelopes of evolved stars. Moreover, organic (aromatic and aliphatic) compounds have been detected in proto-planetary nebulae and planetary nebulae, which are the descendants of carbon stars. This implies that molecular synthesis is actively happening in the circumstellar environment on timescales as short as several hundred years. The detection of stellar grains in the Solar System suggests that they can survive their journey through the interstellar medium and that they are a major contributor of interstellar grains. PMID:15329712

  1. Bacterial resistance to antimicrobial peptides: an evolving phenomenon.

    PubMed

    Fleitas, Osmel; Agbale, Caleb M; Franco, Octavio L

    2016-01-01

    Bacterial resistance to conventional antibiotics is currently a real problem all over the world, making novel antimicrobial compounds a real research priority. Some of the most promising compounds found to date are antimicrobial peptides (AMPs). The benefits of these drugs include their broad spectrum of activity that affects several microbial processes, making the emergence of resistance less likely. However, bacterial resistance to AMPs is an evolving phenomenon that compromises the therapeutic potential of these compounds. Therefore, it is mandatory to understand bacterial mechanisms of resistance to AMPs in depth, in order to develop more powerful AMPs that overcome the bacterial resistance response.

  2. IRAS observations of extended dust envelopes around evolved stars

    NASA Technical Reports Server (NTRS)

    Hawkins, George

    1990-01-01

    Deconvolved IRAS profiles, with resolution 2-3 time better than detector sizes 1.5 and 3 arcmin at 60 and 100 microns, are presented for a number of evolved stars with extended emission. These include VY UMa, Mu Cep, S Sct, U Hya, Y CVn, U Ant, alpha Ori, Y Pav, UU aur, IRC + 10216, RZ Sgr, and R Lyr. Simple models suggest that extended IRAS emission results from stars which greater mass loss rates in the past, rather than from stars with large current mass loss rates.

  3. Evolving Pharmacotherapies for the Treatment of Metastatic Melanoma

    PubMed Central

    Salama, April K.S.

    2013-01-01

    Metastatic melanoma remains a difficult disease to treat, and long term survivors are rare. Over the past few years, however, breakthroughs in both immunotherapy as well as targeted agents have had a tremendous impact on patients diagnosed with this disease. This review summarizes recent advances in systemic therapies for melanoma, including immune modulators directed against cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and programmed death-1 (PD-1), as well as a number of targeted agents. These approaches hold great promise as the landscape of therapeutic options for advanced melanoma continues to evolve. PMID:23843723

  4. Commentary on “Biophysical Economics” and Evolving Areas

    NASA Astrophysics Data System (ADS)

    Flomenbom, Ophir; Coban, Gul Unal; Adigüzel, Yekbun

    2016-07-01

    In this Issue, papers in the area of socio-econo-physics and biophysical economics are presented. We have recently introduced socio-econo-physics and biophysical economics in Biophysical Reviews and Letters (BRL), yet saw 3 to 4 relevant papers just in these most recent three quarters. In this commentary, we therefore would like to elaborate on the topics of socio-econo-physics and biophysical economics and to introduce these concepts to the readers of BRL and the biophysical community of science, with the purpose of supporting many more publications here in BRL, in this evolving area.

  5. Gravity effects on information filtering and network evolving.

    PubMed

    Liu, Jin-Hu; Zhang, Zi-Ke; Chen, Lingjiao; Liu, Chuang; Yang, Chengcheng; Wang, Xueqi

    2014-01-01

    In this paper, based on the gravity principle of classical physics, we propose a tunable gravity-based model, which considers tag usage pattern to weigh both the mass and distance of network nodes. We then apply this model in solving the problems of information filtering and network evolving. Experimental results on two real-world data sets, Del.icio.us and MovieLens, show that it can not only enhance the algorithmic performance, but can also better characterize the properties of real networks. This work may shed some light on the in-depth understanding of the effect of gravity model.

  6. Autophagy and bacterial infection: an evolving arms race.

    PubMed

    Choy, Augustine; Roy, Craig R

    2013-09-01

    Autophagy is an important membrane transport pathway that is conserved among eukaryotic cells. Although first described as an intracellular catabolic pathway used to break down self-components, autophagy has been found to play an important role in the elimination of intracellular pathogens. A variety of host mechanisms exist for recognizing and targeting intracellular bacteria to autophagosomes. Several intracellular bacteria have evolved ways to manipulate, inhibit, or avoid autophagy in order to survive in the cell. Thus, the autophagy pathway can be viewed as an evolutionarily conserved host response to infection.

  7. Raman spectroscopy: an evolving technique for live cell studies.

    PubMed

    Smith, Rachael; Wright, Karen L; Ashton, Lorna

    2016-06-21

    One of the most exciting developments in Raman spectroscopy in the last decade has been its application to cells and tissues for diagnostic and pharmaceutical applications, and in particular its use in the analysis of cellular dynamics. Raman spectroscopy is rapidly advancing as a cell imaging method that overcomes many of the limitations of current techniques and is earning its place as a routine tool in cell biology. In this review we focus on important developments in Raman spectroscopy that have evolved into the exciting technique of live-cell Raman microscopy and highlight some of the most recent and significant applications to cell biology.

  8. Recycling of Aluminum Salt Cake: Utilization of Evolved Ammonia

    NASA Astrophysics Data System (ADS)

    Li, Peng; Zhang, Mei; Teng, Lidong; Seetharaman, Seshadri

    2013-02-01

    The communication presents an extension of the leaching process of the salt cake earlier developed by the present authors. The process describes the investigations in capturing the ammonia gas evolved by hydrolysis of AlN during aqueous leaching at 373 K (100 °C) by CO2-saturated water. The product, i.e., ammonium bicarbonate which is free of chlorides, is a value-added product and can find application in the fertilizer industry. The present method has the added advantage of fixing CO2 as well.

  9. Simulations of embodied evolving semiosis: Emergent semantics in artificial environments

    SciTech Connect

    Rocha, L.M.; Joslyn, C.

    1998-02-01

    As we enter this amazing new world of artificial and virtual systems and environments in the context of human communities, we are interested in the development of systems and environments which have the capacity to grow and evolve their own meanings in the context of this community of interaction. In this paper the authors analyze the necessary conditions to achieve systems and environments with these properties: (1) a coupled interaction between a system and its environment; (2) an environment with sufficient initial richness and structure to allow for; (3) embodied emergent classification of that environment system coupling; and (4) which is subject to pragmatic selection.

  10. Child sexual abuse and forensic psychiatry: evolving and controversial issues.

    PubMed

    Burton, K; Myers, W C

    1992-01-01

    Child sexual abuse has received growing attention in recent years, and the topic continues to spark controversy among mental health and legal professionals as well as in the popular media. This paper will review the concept of child sexual abuse, cover relevant definitions, address the clinician's role, and then will address the principal evolving and controversial areas. These areas include psychic damages, false allegations, improper investigatory techniques, use of anatomical dolls, admissibility of expert testimony, hearsay testimony, and the competency of minors to testify. PMID:1482798

  11. Evolving extrinsic curvature and the cosmological constant problem

    NASA Astrophysics Data System (ADS)

    Capistrano, Abraão J. S.; Cabral, Luis A.

    2016-10-01

    The concept of smooth deformation of Riemannian manifolds associated with the extrinsic curvature is explained and applied to the Friedmann-Lemaître-Robertson-Walker cosmology. We show that such deformation can be derived from the Einstein-Hilbert-like dynamical principle may produce an observable effect in the sense of Noether. As a result, we show how the extrinsic curvature compensates both quantitative and qualitative differences between the cosmological constant Λ and the vacuum energy {ρ }{vac} obtaining the observed upper bound for the cosmological constant problem at electroweak scale. The topological characteristics of the extrinsic curvature are discussed showing that the produced extrinsic scalar curvature is an evolving dynamical quantity.

  12. Using ESB and BPEL for evolving healthcare systems towards SOA.

    PubMed

    Papakonstantinou, D; Malamateniou, F; Vassilacopoulos, G

    2008-01-01

    Healthcare organizations often face the challenge of integrating diverse and geographically disparate information technology systems to respond to changing requirements and to exploit the capabilities of modern technologies. Hence, systems evolution, through modification and extension of the existing information technology infrastructure, becomes a necessity. This paper takes a process perspective of healthcare delivery within and across organizational boundaries and the presents a disciplined approach for evolving healthcare systems towards a service-oriented architecture using the enterprise system bus middleware technology for resolving integration issues and the business process execution language for supporting collaboration requirements. PMID:18487821

  13. The Concepts that Revolutionized the Field of Infectious Diseases.

    PubMed

    Chaudhari, Piyush; Shetty, Anjali; Soman, Rajeev

    2015-08-01

    The fields of Microbiology and Infectious diseases have developed tremendously in the 19th and the 20th centuries. Four revolutionary concepts that evolved during this period form the cornerstones on which these fields have developed further. PMID:27604447

  14. A guide for the design of evolve and resequencing studies.

    PubMed

    Kofler, Robert; Schlötterer, Christian

    2014-02-01

    Standing genetic variation provides a rich reservoir of potentially useful mutations facilitating the adaptation to novel environments. Experimental evolution studies have demonstrated that rapid and strong phenotypic responses to selection can also be obtained in the laboratory. When combined with the next-generation sequencing technology, these experiments promise to identify the individual loci contributing to adaption. Nevertheless, until now, very little is known about the design of such evolve & resequencing (E&R) studies. Here, we use forward simulations of entire genomes to evaluate different experimental designs that aim to maximize the power to detect selected variants. We show that low linkage disequilibrium in the starting population, population size, duration of the experiment, and the number of replicates are the key factors in determining the power and accuracy of E&R studies. Furthermore, replication of E&R is more important for detecting the targets of selection than increasing the population size. Using an optimized design, beneficial loci with a selective advantage as low as s = 0.005 can be identified at the nucleotide level. Even when a large number of loci are selected simultaneously, up to 56% can be reliably detected without incurring large numbers of false positives. Our computer simulations suggest that, with an adequate experimental design, E&R studies are a powerful tool to identify adaptive mutations from standing genetic variation and thereby provide an excellent means to analyze the trajectories of selected alleles in evolving populations.

  15. Evolving effective behaviours to interact with tag-based populations

    NASA Astrophysics Data System (ADS)

    Yucel, Osman; Crawford, Chad; Sen, Sandip

    2015-07-01

    Tags and other characteristics, externally perceptible features that are consistent among groups of animals or humans, can be used by others to determine appropriate response strategies in societies. This usage of tags can be extended to artificial environments, where agents can significantly reduce cognitive effort spent on appropriate strategy choice and behaviour selection by reusing strategies for interacting with new partners based on their tags. Strategy selection mechanisms developed based on this idea have successfully evolved stable cooperation in games such as the Prisoner's Dilemma game but relies upon payoff sharing and matching methods that limit the applicability of the tag framework. Our goal is to develop a general classification and behaviour selection approach based on the tag framework. We propose and evaluate alternative tag matching and adaptation schemes for a new, incoming individual to select appropriate behaviour against any population member of an existing, stable society. Our proposed approach allows agents to evolve both the optimal tag for the environment as well as appropriate strategies for existing agent groups. We show that these mechanisms will allow for robust selection of optimal strategies by agents entering a stable society and analyse the various environments where this approach is effective.

  16. EVOLVE 5.0 historical and projected orbital debris environments

    NASA Astrophysics Data System (ADS)

    Krisko, P.; Anz-Meador, P.; Opiela, J.; Matney, M.

    The NASA/JSC orbital debris research effort within Earth's low-altitude orbit continues with the upgrade of the debris environment simulation model EVOLVE to version 5.0. Two main improvements to this new version include an updated, expanded set of launch/orbital injection files and an upgraded explosion fragmentation model. The new database includes such improvements as high fidelity launch times and orbital elements, data-derived area-to-mass ratios, and individual object dry mass and physical description. The new explosion model is a modification of the previous version in the 10-cm through 1-mm size regime. This is the debris population that the previous model slightly overestimated. Resulting present day environments are presented in comparison to the US SPACECOM Space Surveillance Network (SSN) catalog and Haystack radar and Haystack Auxiliary Radar (HAX) data. Long-term projection environments, given presumed future launch rates and mitigation measures, are also shown and compared with those of the previous version of EVOLVE.

  17. Functional modules of sigma factor regulons guarantee adaptability and evolvability

    NASA Astrophysics Data System (ADS)

    Binder, Sebastian C.; Eckweiler, Denitsa; Schulz, Sebastian; Bielecka, Agata; Nicolai, Tanja; Franke, Raimo; Häussler, Susanne; Meyer-Hermann, Michael

    2016-02-01

    The focus of modern molecular biology turns from assigning functions to individual genes towards understanding the expression and regulation of complex sets of molecules. Here, we provide evidence that alternative sigma factor regulons in the pathogen Pseudomonas aeruginosa largely represent insulated functional modules which provide a critical level of biological organization involved in general adaptation and survival processes. Analysis of the operational state of the sigma factor network revealed that transcription factors functionally couple the sigma factor regulons and significantly modulate the transcription levels in the face of challenging environments. The threshold quality of newly evolved transcription factors was reached faster and more robustly in in silico testing when the structural organization of sigma factor networks was taken into account. These results indicate that the modular structures of alternative sigma factor regulons provide P. aeruginosa with a robust framework to function adequately in its environment and at the same time facilitate evolutionary change. Our data support the view that widespread modularity guarantees robustness of biological networks and is a key driver of evolvability.

  18. Evolutionary Stability of Jointly Evolving Traits in Subdivided Populations.

    PubMed

    Mullon, Charles; Keller, Laurent; Lehmann, Laurent

    2016-08-01

    The evolutionary stability of quantitative traits depends on whether a population can resist invasion by any mutant. While uninvadability is well understood in well-mixed populations, it is much less so in subdivided populations when multiple traits evolve jointly. Here, we investigate whether a spatially subdivided population at a monomorphic equilibrium for multiple traits can withstand invasion by any mutant or is subject to diversifying selection. Our model also explores the correlations among traits arising from diversifying selection and how they depend on relatedness due to limited dispersal. We find that selection tends to favor a positive (negative) correlation between two traits when the selective effects of one trait on relatedness is positively (negatively) correlated to the indirect fitness effects of the other trait. We study the evolution of traits for which this matters: dispersal that decreases relatedness and helping that has positive indirect fitness effects. We find that when dispersal cost is low and the benefits of helping accelerate faster than its costs, selection leads to the coexistence of mobile defectors and sessile helpers. Otherwise, the population evolves to a monomorphic state with intermediate helping and dispersal. Overall, our results highlight the effects of population subdivision for evolutionary stability and correlations among traits. PMID:27420783

  19. Destruction of Interstellar Dust in Evolving Supernova Remnant Shock Waves

    NASA Technical Reports Server (NTRS)

    Slavin, Jonathan D.; Dwek, Eli; Jones, Anthony P.

    2015-01-01

    Supernova generated shock waves are responsible for most of the destruction of dust grains in the interstellar medium (ISM). Calculations of the dust destruction timescale have so far been carried out using plane parallel steady shocks, however that approximation breaks down when the destruction timescale becomes longer than that for the evolution of the supernova remnant (SNR) shock. In this paper we present new calculations of grain destruction in evolving, radiative SNRs. To facilitate comparison with the previous study by Jones et al. (1996), we adopt the same dust properties as in that paper. We find that the efficiencies of grain destruction are most divergent from those for a steady shock when the thermal history of a shocked gas parcel in the SNR differs significantly from that behind a steady shock. This occurs in shocks with velocities 200 km s(exp -1) for which the remnant is just beginning to go radiative. Assuming SNRs evolve in a warm phase dominated ISM, we find dust destruction timescales are increased by a factor of approximately 2 compared to those of Jones et al. (1996), who assumed a hot gas dominated ISM. Recent estimates of supernova rates and ISM mass lead to another factor of approximately 3 increase in the destruction timescales, resulting in a silicate grain destruction timescale of approximately 2-3 Gyr. These increases, while not able resolve the problem of the discrepant timescales for silicate grain destruction and creation, are an important step towards understanding the origin, and evolution of dust in the ISM.

  20. Genetic distance and species formation in evolving populations.

    PubMed

    Higgs, P G; Derrida, B

    1992-11-01

    We compare the behavior of the genetic distance between individuals in evolving populations for three stochastic models. In the first model reproduction is asexual and the distribution of genetic distances reflects the genealogical tree of the population. This distribution fluctuates greatly in time, even for very large populations. In the second model reproduction is sexual with random mating allowed between any pair of individuals. In this case, the population becomes homogeneous and the genetic distance between pairs of individuals has small fluctuations which vanish in the limit of an infinitely large population. In the third model reproduction is still sexual but instead of random mating, mating only occurs between individuals which are genetically similar to each other. In that case, the population splits spontaneously into species which are in reproductive isolation from one another and one observes a steady state with a continual appearance and extinction of species in the population. We discuss this model in relation to the biological theory of speciation and isolating mechanisms. We also point out similarities between these three models of evolving populations and the theory of disordered systems in physics. PMID:1487829

  1. Constrained evolvability of interferon suppression in an RNA virus

    PubMed Central

    Garijo, Raquel; Cuevas, José M.; Briz, Álvaro; Sanjuán, Rafael

    2016-01-01

    Innate immunity responses controlled by interferon (IFN) are believed to constitute a major selective pressure shaping viral evolution. Viruses encode a variety of IFN suppressors, but these are often multifunctional proteins that also play essential roles in other steps of the viral infection cycle, possibly limiting their evolvability. Here, we experimentally evolved a vesicular stomatitis virus (VSV) mutant carrying a defect in the matrix protein (M∆51) that abolishes IFN suppression and that has been previously used in the context of oncolytic virotherapy. Serial transfers of this virus in normal, IFN-secreting cells led to a modest recovery of IFN blocking capacity and to weak increases in viral fitness. Full-genome ultra-deep sequencing and phenotypic analysis of population variants revealed that the anti-IFN function of the matrix protein was not restored, and that the Mdelta51 defect was instead compensated by changes in the viral phosphoprotein. We also show that adaptation to IFN-secreting cells can be driven by the selection of fast-growing viruses with no IFN suppression capacity, and that these population variants can be trans-complemented by other, IFN-suppressing variants. Our results thus suggest that virus-virus interactions and alternative strategies of innate immunity evasion can determine the evolution of IFN suppression in a virus. PMID:27098004

  2. Modelling cell motility and chemotaxis with evolving surface finite elements

    PubMed Central

    Elliott, Charles M.; Stinner, Björn; Venkataraman, Chandrasekhar

    2012-01-01

    We present a mathematical and a computational framework for the modelling of cell motility. The cell membrane is represented by an evolving surface, with the movement of the cell determined by the interaction of various forces that act normal to the surface. We consider external forces such as those that may arise owing to inhomogeneities in the medium and a pressure that constrains the enclosed volume, as well as internal forces that arise from the reaction of the cells' surface to stretching and bending. We also consider a protrusive force associated with a reaction–diffusion system (RDS) posed on the cell membrane, with cell polarization modelled by this surface RDS. The computational method is based on an evolving surface finite-element method. The general method can account for the large deformations that arise in cell motility and allows the simulation of cell migration in three dimensions. We illustrate applications of the proposed modelling framework and numerical method by reporting on numerical simulations of a model for eukaryotic chemotaxis and a model for the persistent movement of keratocytes in two and three space dimensions. Movies of the simulated cells can be obtained from http://homepages.warwick.ac.uk/∼maskae/CV_Warwick/Chemotaxis.html. PMID:22675164

  3. Evolving technologies drive the new roles of Biomedical Engineering.

    PubMed

    Frisch, P H; St Germain, J; Lui, W

    2008-01-01

    Rapidly changing technology coupled with the financial impact of organized health care, has required hospital Biomedical Engineering organizations to augment their traditional operational and business models to increase their role in developing enhanced clinical applications utilizing new and evolving technologies. The deployment of these technology based applications has required Biomedical Engineering organizations to re-organize to optimize the manner in which they provide and manage services. Memorial Sloan-Kettering Cancer Center has implemented a strategy to explore evolving technologies integrating them into enhanced clinical applications while optimally utilizing the expertise of the traditional Biomedical Engineering component (Clinical Engineering) to provide expanded support in technology / equipment management, device repair, preventive maintenance and integration with legacy clinical systems. Specifically, Biomedical Engineering is an integral component of the Medical Physics Department which provides comprehensive and integrated support to the Center in advanced physical, technical and engineering technology. This organizational structure emphasizes the integration and collaboration between a spectrum of technical expertise for clinical support and equipment management roles. The high cost of clinical equipment purchases coupled with the increasing cost of service has driven equipment management responsibilities to include significant business and financial aspects to provide a cost effective service model. This case study details the dynamics of these expanded roles, future initiatives and benefits for Biomedical Engineering and Memorial Sloan Kettering Cancer Center.

  4. Evolving technologies drive the new roles of Biomedical Engineering.

    PubMed

    Frisch, P H; St Germain, J; Lui, W

    2008-01-01

    Rapidly changing technology coupled with the financial impact of organized health care, has required hospital Biomedical Engineering organizations to augment their traditional operational and business models to increase their role in developing enhanced clinical applications utilizing new and evolving technologies. The deployment of these technology based applications has required Biomedical Engineering organizations to re-organize to optimize the manner in which they provide and manage services. Memorial Sloan-Kettering Cancer Center has implemented a strategy to explore evolving technologies integrating them into enhanced clinical applications while optimally utilizing the expertise of the traditional Biomedical Engineering component (Clinical Engineering) to provide expanded support in technology / equipment management, device repair, preventive maintenance and integration with legacy clinical systems. Specifically, Biomedical Engineering is an integral component of the Medical Physics Department which provides comprehensive and integrated support to the Center in advanced physical, technical and engineering technology. This organizational structure emphasizes the integration and collaboration between a spectrum of technical expertise for clinical support and equipment management roles. The high cost of clinical equipment purchases coupled with the increasing cost of service has driven equipment management responsibilities to include significant business and financial aspects to provide a cost effective service model. This case study details the dynamics of these expanded roles, future initiatives and benefits for Biomedical Engineering and Memorial Sloan Kettering Cancer Center. PMID:19163865

  5. Evolving a Behavioral Repertoire for a Walking Robot.

    PubMed

    Cully, A; Mouret, J-B

    2016-01-01

    Numerous algorithms have been proposed to allow legged robots to learn to walk. However, most of these algorithms are devised to learn walking in a straight line, which is not sufficient to accomplish any real-world mission. Here we introduce the Transferability-based Behavioral Repertoire Evolution algorithm (TBR-Evolution), a novel evolutionary algorithm that simultaneously discovers several hundreds of simple walking controllers, one for each possible direction. By taking advantage of solutions that are usually discarded by evolutionary processes, TBR-Evolution is substantially faster than independently evolving each controller. Our technique relies on two methods: (1) novelty search with local competition, which searches for both high-performing and diverse solutions, and (2) the transferability approach, which combines simulations and real tests to evolve controllers for a physical robot. We evaluate this new technique on a hexapod robot. Results show that with only a few dozen short experiments performed on the robot, the algorithm learns a repertoire of controllers that allows the robot to reach every point in its reachable space. Overall, TBR-Evolution introduced a new kind of learning algorithm that simultaneously optimizes all the achievable behaviors of a robot.

  6. Salt tolerance evolves more frequently in C4 grass lineages.

    PubMed

    Bromham, L; Bennett, T H

    2014-03-01

    Salt tolerance has evolved many times in the grass family, and yet few cereal crops are salt tolerant. Why has it been so difficult to develop crops tolerant of saline soils when salt tolerance has evolved so frequently in nature? One possible explanation is that some grass lineages have traits that predispose them to developing salt tolerance and that without these background traits, salt tolerance is harder to achieve. One candidate background trait is photosynthetic pathway, which has also been remarkably labile in grasses. At least 22 independent origins of the C4 photosynthetic pathway have been suggested to occur within the grass family. It is possible that the evolution of C4 photosynthesis aids exploitation of saline environments, because it reduces transpiration, increases water-use efficiency and limits the uptake of toxic ions. But the observed link between the evolution of C4 photosynthesis and salt tolerance could simply be due to biases in phylogenetic distribution of halophytes or C4 species. Here, we use a phylogenetic analysis to investigate the association between photosynthetic pathway and salt tolerance in the grass family Poaceae. We find that salt tolerance is significantly more likely to occur in lineages with C4 photosynthesis than in C3 lineages. We discuss the possible links between C4 photosynthesis and salt tolerance and consider the limitations of inferring the direction of causality of this relationship.

  7. THROES: A Catalogue of Herschel Observations of Evolved Stars

    NASA Astrophysics Data System (ADS)

    Ramos-Medina, J.; Sánchez-Contreras, C.; García-Lario, P.; Rodrigo, C.

    2015-12-01

    We are building a catalogue of fully-reprocessed observations of all evolved stars observed with Herschel (THROES). In a first stage, we focus on observations performed with the PACS instrument in its full range spectroscopy mode. Once finished, the catalogue will offer all reduced data for each observation, as well as, complementary information from other observatories. As a first step, we concentrate our efforts on two main activities: 1) the reprocessing and data-reduction of more than 200 individual sources, observed by Herschel/PACS in the 55-210 micron range, available in the Herschel Science Archive (HSA); 2) The creation of an initial catalogue, accesible via web and the Virtual Observatory (VO), with all the information relative to PACS observations and the classification of the sources. Our ultimate goal will be to carry out a comprehensive and systematic study of the far infrared properties of low-and intermediate-mass (1-8 FX1) evolved stars using these data. These objects cover the whole range of possible evolutionary stages in this short-lived phase of stellar evolution, from AGB phase to the PN stage, displaying a wide variety of chemical and physical properties.

  8. Evolving a Behavioral Repertoire for a Walking Robot.

    PubMed

    Cully, A; Mouret, J-B

    2016-01-01

    Numerous algorithms have been proposed to allow legged robots to learn to walk. However, most of these algorithms are devised to learn walking in a straight line, which is not sufficient to accomplish any real-world mission. Here we introduce the Transferability-based Behavioral Repertoire Evolution algorithm (TBR-Evolution), a novel evolutionary algorithm that simultaneously discovers several hundreds of simple walking controllers, one for each possible direction. By taking advantage of solutions that are usually discarded by evolutionary processes, TBR-Evolution is substantially faster than independently evolving each controller. Our technique relies on two methods: (1) novelty search with local competition, which searches for both high-performing and diverse solutions, and (2) the transferability approach, which combines simulations and real tests to evolve controllers for a physical robot. We evaluate this new technique on a hexapod robot. Results show that with only a few dozen short experiments performed on the robot, the algorithm learns a repertoire of controllers that allows the robot to reach every point in its reachable space. Overall, TBR-Evolution introduced a new kind of learning algorithm that simultaneously optimizes all the achievable behaviors of a robot. PMID:25585055

  9. Functional modules of sigma factor regulons guarantee adaptability and evolvability.

    PubMed

    Binder, Sebastian C; Eckweiler, Denitsa; Schulz, Sebastian; Bielecka, Agata; Nicolai, Tanja; Franke, Raimo; Häussler, Susanne; Meyer-Hermann, Michael

    2016-01-01

    The focus of modern molecular biology turns from assigning functions to individual genes towards understanding the expression and regulation of complex sets of molecules. Here, we provide evidence that alternative sigma factor regulons in the pathogen Pseudomonas aeruginosa largely represent insulated functional modules which provide a critical level of biological organization involved in general adaptation and survival processes. Analysis of the operational state of the sigma factor network revealed that transcription factors functionally couple the sigma factor regulons and significantly modulate the transcription levels in the face of challenging environments. The threshold quality of newly evolved transcription factors was reached faster and more robustly in in silico testing when the structural organization of sigma factor networks was taken into account. These results indicate that the modular structures of alternative sigma factor regulons provide P. aeruginosa with a robust framework to function adequately in its environment and at the same time facilitate evolutionary change. Our data support the view that widespread modularity guarantees robustness of biological networks and is a key driver of evolvability. PMID:26915971

  10. Endless forms: human behavioural diversity and evolved universals

    PubMed Central

    Smith, Eric Alden

    2011-01-01

    Human populations have extraordinary capabilities for generating behavioural diversity without corresponding genetic diversity or change. These capabilities and their consequences can be grouped into three categories: strategic (or cognitive), ecological and cultural-evolutionary. Strategic aspects include: (i) a propensity to employ complex conditional strategies, some certainly genetically evolved but others owing to directed invention or to cultural evolution; (ii) situations in which fitness payoffs (or utilities) are frequency-dependent, so that there is no one best strategy; and (iii) the prevalence of multiple equilibria, with history or minor variations in starting conditions (path dependence) playing a crucial role. Ecological aspects refer to the fact that social behaviour and cultural institutions evolve in diverse niches, producing various adaptive radiations and local adaptations. Although environmental change can drive behavioural change, in humans, it is common for behavioural change (especially technological innovation) to drive environmental change (i.e. niche construction). Evolutionary aspects refer to the fact that human capacities for innovation and cultural transmission lead to diversification and cumulative cultural evolution; critical here is institutional design, in which relatively small shifts in incentive structure can produce very different aggregate outcomes. In effect, institutional design can reshape strategic games, bringing us full circle. PMID:21199837

  11. Can functionality in evolving networks be explained reductively?

    PubMed

    Krohs, Ulrich

    2015-10-01

    Philosophers of biology disagree about an adequate explication of the concept of function. Instead of perpetuating the debate on the level of in principle-arguments, this paper aims first at reconstructing functional talk in the biological research papers of Marom and Braun, which focus on two different kinds of evolving networks, and in discussing the ontological consequences which the authors draw from their results. Marom investigates evolving neural networks controlling Braitenberg vehicles. Braun observes the evolutionary rearrangement or "rewiring" of the genetic network of genetically modified yeast on a short time scale. In both cases, the parameters under investigation are defined in functional terms. However, both authors report striking differences in the structures that realize one and the same function, as well as striking differences in the function of identical structures. From this, they construct an argument against reductionism. The second aim of my paper is an inquiry into the epistemic legitimacy of this conclusion. This requires addressing critically several concepts on which Marom and Braun's argument is built. PMID:25899912

  12. Evolving communicative complexity: insights from rodents and beyond.

    PubMed

    Pollard, Kimberly A; Blumstein, Daniel T

    2012-07-01

    Social living goes hand in hand with communication, but the details of this relationship are rarely simple. Complex communication may be described by attributes as diverse as a species' entire repertoire, signallers' individualistic signatures, or complex acoustic phenomena within single calls. Similarly, attributes of social complexity are diverse and may include group size, social role diversity, or networks of interactions and relationships. How these different attributes of social and communicative complexity co-evolve is an active question in behavioural ecology. Sciurid rodents (ground squirrels, prairie dogs and marmots) provide an excellent model system for studying these questions. Sciurid studies have found that demographic role complexity predicts alarm call repertoire size, while social group size predicts alarm call individuality. Along with other taxa, sciurids reveal an important insight: different attributes of sociality are linked to different attributes of communication. By breaking social and communicative complexity down to different attributes, focused studies can better untangle the underlying evolutionary relationships and move us closer to a comprehensive theory of how sociality and communication evolve. PMID:22641825

  13. Scalability, Timing, and System Design Issues for Intrinsic Evolvable Hardware

    NASA Technical Reports Server (NTRS)

    Hereford, James; Gwaltney, David

    2004-01-01

    In this paper we address several issues pertinent to intrinsic evolvable hardware (EHW). The first issue is scalability; namely, how the design space scales as the programming string for the programmable device gets longer. We develop a model for population size and the number of generations as a function of the programming string length, L, and show that the number of circuit evaluations is an O(L2) process. We compare our model to several successful intrinsic EHW experiments and discuss the many implications of our model. The second issue that we address is the timing of intrinsic EHW experiments. We show that the processing time is a small part of the overall time to derive or evolve a circuit and that major improvements in processor speed alone will have only a minimal impact on improving the scalability of intrinsic EHW. The third issue we consider is the system-level design of intrinsic EHW experiments. We review what other researchers have done to break the scalability barrier and contend that the type of reconfigurable platform and the evolutionary algorithm are tied together and impose limits on each other.

  14. Evolving the future: toward a science of intentional change.

    PubMed

    Wilson, David Sloan; Hayes, Steven C; Biglan, Anthony; Embry, Dennis D

    2014-08-01

    Humans possess great capacity for behavioral and cultural change, but our ability to manage change is still limited. This article has two major objectives: first, to sketch a basic science of intentional change centered on evolution; second, to provide examples of intentional behavioral and cultural change from the applied behavioral sciences, which are largely unknown to the basic sciences community. All species have evolved mechanisms of phenotypic plasticity that enable them to respond adaptively to their environments. Some mechanisms of phenotypic plasticity count as evolutionary processes in their own right. The human capacity for symbolic thought provides an inheritance system having the same kind of combinatorial diversity as does genetic recombination and antibody formation. Taking these propositions seriously allows an integration of major traditions within the basic behavioral sciences, such as behaviorism, social constructivism, social psychology, cognitive psychology, and evolutionary psychology, which are often isolated and even conceptualized as opposed to one another. The applied behavioral sciences include well-validated examples of successfully managing behavioral and cultural change at scales ranging from individuals to small groups to large populations. However, these examples are largely unknown beyond their disciplinary boundaries, for lack of a unifying theoretical framework. Viewed from an evolutionary perspective, they are examples of managing evolved mechanisms of phenotypic plasticity, including open-ended processes of variation and selection. Once the many branches of the basic and applied behavioral sciences become conceptually unified, we are closer to a science of intentional change than one might think. PMID:24826907

  15. An Evolvable Space Telescope for Future Astronomical Missions

    NASA Astrophysics Data System (ADS)

    Polidan, Ronald S.; Breckinridge, James B.; Lillie, Charles F.; MacEwen, Howard A.; Flannery, Martin; Dailey, Dean

    2015-01-01

    Astronomical flagship missions after the James Webb Space Telescope (JWST) will require lower cost space telescopes and science instruments. Innovative spacecraft-electro-opto-mechanical system architectures matched to the science requirements are needed for observations for exoplanet characterization, cosmology, dark energy, galactic evolution formation of stars and planets, and many other research areas. The needs and requirements to perform this science will continue to drive us toward larger and larger apertures.Recent technology developments in precision station keeping of spacecraft, interplanetary transfer orbits, wavefront/sensing and control, laser engineering, macroscopic application of nano-technology, lossless optical designs, deployed structures, thermal management, interferometry, detectors and signal processing enable innovative telescope/system architectures with break-through performance.Unfortunately, NASA's budget for Astrophysics is unlikely to be able to support the funding required for the 8-m to 16-m telescopes that have been studied for the follow-on to JWST using similar development/assembly approaches without accounting for too large of a portion of the Astrophysics Division's budget. Consequently, we have been examining the feasibility of developing an 'Evolvable Space Telescope' that would be 3 to 4-m when placed on orbit and then periodically augmented with additional mirror segments, structures, and newer instruments to evolve the telescope and achieve the performance of a 16-m space telescope.This paper reviews the technologies required for such a mission, identifies candidate architectures, and discusses different science measurement objectives for these architectures.

  16. An evolvable space telescope for future astronomical missions

    NASA Astrophysics Data System (ADS)

    Polidan, Ronald S.; Breckinridge, James B.; Lillie, Charles F.; MacEwen, Howard A.; Flannery, Martin R.; Dailey, Dean R.

    2014-08-01

    Astronomical flagship missions after JWST will require affordable space telescopes and science instruments. Innovative spacecraft-electro-opto-mechanical system architectures matched to the science requirements are needed for observations for exoplanet characterization, cosmology, dark energy, galactic evolution formation of stars and planets, and many other research areas. The needs and requirements to perform this science will continue to drive us toward larger and larger apertures. Recent technology developments in precision station keeping of spacecraft, interplanetary transfer orbits, wavefront/sensing and control, laser engineering, macroscopic application of nano-technology, lossless optical designs, deployed structures, thermal management, interferometry, detectors and signal processing enable innovative telescope/system architectures with break-through performance. Unfortunately, NASA's budget for Astrophysics is unlikely to be able to support the funding required for the 8 m to 16 m telescopes that have been studied as a follow-on to JWST using similar development/assembly approaches without decimating the rest of the Astrophysics Division's budget. Consequently, we have been examining the feasibility of developing an "Evolvable Space Telescope" that would begin as a 3 to 4 m telescope when placed on orbit and then periodically be augmented with additional mirror segments, structures, and newer instruments to evolve the telescope and achieve the performance of a 16 m or larger space telescope. This paper reviews the approach for such a mission and identifies and discusses candidate architectures.

  17. An analysis of why highly similar enzymes evolve differently.

    PubMed Central

    Majiduddin, Fahd K; Palzkill, Timothy

    2003-01-01

    The TEM-1 and SHV-1 beta-lactamases are important contributors to resistance to beta-lactam antibiotics in gram-negative bacteria. These enzymes share 68% amino acid sequence identity and their atomic structures are nearly superimposable. Extended-spectrum cephalosporins were introduced to avoid the action of these beta-lactamases. The widespread use of antibiotics has led to the evolution of variant TEM and SHV enzymes that can hydrolyze extended-spectrum antibiotics. Despite being highly similar in structure, the TEM and SHV enzymes have evolved differently in response to the selective pressure of antibiotic therapy. Examples of this are at residues Arg164 and Asp179. Among TEM variants, substitutions are found only at position 164, while among SHV variants, substitutions are found only at position 179. To explain this observation, the effects of substitutions at position 164 in both TEM-1 and SHV-1 on antibiotic resistance and on enzyme catalytic efficiency were examined. Competition experiments were performed between mutants to understand why certain substitutions preferentially evolve in response to the selective pressure of antibiotic therapy. The data presented here indicate that substitutions at position Asp179 in SHV-1 and Arg164 in TEM-1 are more beneficial to bacteria because they provide increased fitness relative to either wild type or other mutants. PMID:12618385

  18. Highly evolved rhyolitic glass compositions from the Toba Caldera, Sumatra

    SciTech Connect

    Chesner, C.A.

    1985-01-01

    The quartz latite to rhyolitic ash flow tuffs erupted form the Toba Caldera, perhaps the largest caldera on earth (100 by 30 kms), provide the unique opportunity to study a highly differentiated liquid in equilibrium with numerous mineral phases. Not only are the rocks very crystal rich (30-50%), but at present a minimum of 15 co-existing mineral phases have been identified. Both whole-rock and glass analyses were made by XRF techniques providing data on both major and trace elements. Whole rock chemistry of individual pumices from the youngest eruption at Toba (75,000 years ago), are suggestive of the eruption of two magma compositions across a boundary layer in the magma chamber. Glass chemistry of the pumices also show two distinct liquid compositions. The more silicic pumices, which have the most evolved glass compositions, are similar to the whole rock chemistry of the few aplitic pumices and cognate granitic xenoliths that were collected. This highly evolved composition resulted from the removal of up to 15 mineral phases and may be a fractionation buffered, univariant composition. The glasses from the less silicic pumices are similar to the whole rock chemistry of the more silicic pumice, thus falling nicely on a fractionation trend towards the univariant composition for these rocks. This set of glass compositions allows an independent test for the origin of distal ashes thought to have erupted from Toba and deposited in Malaysia, the Indian Ocean, and as far away as India.

  19. Structural Analysis of an Evolved Transketolase Reveals Divergent Binding Modes

    PubMed Central

    Affaticati, Pierre E.; Dai, Shao-Bo; Payongsri, Panwajee; Hailes, Helen C.; Tittmann, Kai; Dalby, Paul A.

    2016-01-01

    The S385Y/D469T/R520Q variant of E. coli transketolase was evolved previously with three successive smart libraries, each guided by different structural, bioinformatical or computational methods. Substrate-walking progressively shifted the target acceptor substrate from phosphorylated aldehydes, towards a non-phosphorylated polar aldehyde, a non-polar aliphatic aldehyde, and finally a non-polar aromatic aldehyde. Kinetic evaluations on three benzaldehyde derivatives, suggested that their active-site binding was differentially sensitive to the S385Y mutation. Docking into mutants generated in silico from the wild-type crystal structure was not wholly satisfactory, as errors accumulated with successive mutations, and hampered further smart-library designs. Here we report the crystal structure of the S385Y/D469T/R520Q variant, and molecular docking of three substrates. This now supports our original hypothesis that directed-evolution had generated an evolutionary intermediate with divergent binding modes for the three aromatic aldehydes tested. The new active site contained two binding pockets supporting π-π stacking interactions, sterically separated by the D469T mutation. While 3-formylbenzoic acid (3-FBA) preferred one pocket, and 4-FBA the other, the less well-accepted substrate 3-hydroxybenzaldehyde (3-HBA) was caught in limbo with equal preference for the two pockets. This work highlights the value of obtaining crystal structures of evolved enzyme variants, for continued and reliable use of smart library strategies. PMID:27767080

  20. An evolvable space telescope for future astronomical missions 2015 update

    NASA Astrophysics Data System (ADS)

    Polidan, Ronald S.; Breckinridge, James B.; Lillie, Charles F.; MacEwen, Howard A.; Flannery, Martin R.; Dailey, Dean R.; Baldauf, Brian; Makowski, David; Rafanelli, Gerald L.

    2015-09-01

    In 2014 we presented a concept for an Evolvable Space Telescope (EST) that was assembled on orbit in 3 stages, growing from a 4x12 meter telescope in Stage 1, to a 12-meter filled aperture in Stage 2, and then to a 20-meter filled aperture in Stage 3. Stage 1 is launched as a fully functional telescope and begins gathering science data immediately after checkout on orbit. This observatory is then periodically augmented in space with additional mirror segments, structures, and newer instruments to evolve the telescope over the years to a 20-meter space telescope. In this 2015 update of EST we focus upon three items: 1) a restructured Stage 1 EST with three mirror segments forming an off-axis telescope (half a 12-meter filled aperture); 2) more details on the value and architecture of the prime focus instrument accommodation; and 3) a more in depth discussion of the essential in-space infrastructure, early ground testing and a concept for an International Space Station testbed called MoDEST. In addition to the EST discussions we introduce a different alternative telescope architecture: a Rotating Synthetic Aperture (RSA). This is a rectangular primary mirror that can be rotated to fill the UV-plane. The original concept was developed by Raytheon Space and Airborne Systems for non-astronomical applications. In collaboration with Raytheon we have begun to explore the RSA approach as an astronomical space telescope and have initiated studies of science and cost performance.