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  1. Three mechanisms of Red Queen dynamics

    PubMed Central

    Khibnik, A. I.; Kondrashov, A. S.

    1997-01-01

    Models describing systems of coevolving populations often have asymptotically non-equilibrium dynamics (Red Queen dynamics (RQD)). We claim that if evolution is much slower than ecological changes, RQD arises due to either fast ecological processes, slow genetical processes, or to their interaction. The three corresponding generic types of RQD can be studied using singular perturbation theory and have very different properties and biological implications. We present simple examples of ecological, genetical, and ecogenetical RQD and describe how they may be recognized in natural populations. In particular, ecogenetical RQD often involve alternations of long epochs with radically different dynamics.

  2. Chaotic Red Queen coevolution in three-species food chains

    PubMed Central

    Dercole, Fabio; Ferriere, Regis; Rinaldi, Sergio

    2010-01-01

    Coevolution between two antagonistic species follows the so-called ‘Red Queen dynamics’ when reciprocal selection results in an endless series of adaptation by one species and counteradaptation by the other. Red Queen dynamics are ‘genetically driven’ when selective sweeps involving new beneficial mutations result in perpetual oscillations of the coevolving traits on the slow evolutionary time scale. Mathematical models have shown that a prey and a predator can coevolve along a genetically driven Red Queen cycle. We found that embedding the prey–predator interaction into a three-species food chain that includes a coevolving superpredator often turns the genetically driven Red Queen cycle into chaos. A key condition is that the prey evolves fast enough. Red Queen chaos implies that the direction and strength of selection are intrinsically unpredictable beyond a short evolutionary time, with greatest evolutionary unpredictability in the superpredator. We hypothesize that genetically driven Red Queen chaos could explain why many natural populations are poised at the edge of ecological chaos. Over space, genetically driven chaos is expected to cause the evolutionary divergence of local populations, even under homogenizing environmental fluctuations, and thus to promote genetic diversity among ecological communities over long evolutionary time. PMID:20356888

  3. The Red Queen lives: Epistasis between linked resistance loci.

    PubMed

    Metzger, César M J A; Luijckx, Pepijn; Bento, Gilberto; Mariadassou, Mahendra; Ebert, Dieter

    2016-02-01

    A popular theory explaining the maintenance of genetic recombination (sex) is the Red Queen Theory. This theory revolves around the idea that time-lagged negative frequency-dependent selection by parasites favors rare host genotypes generated through recombination. Although the Red Queen has been studied for decades, one of its key assumptions has remained unsupported. The signature host-parasite specificity underlying the Red Queen, where infection depends on a match between host and parasite genotypes, relies on epistasis between linked resistance loci for which no empirical evidence exists. We performed 13 genetic crosses and tested over 7000 Daphnia magna genotypes for resistance to two strains of the bacterial pathogen Pasteuria ramosa. Results reveal the presence of strong epistasis between three closely linked resistance loci. One locus masks the expression of the other two, while these two interact to produce a single resistance phenotype. Changing a single allele on one of these interacting loci can reverse resistance against the tested parasites. Such a genetic mechanism is consistent with host and parasite specificity assumed by the Red Queen Theory. These results thus provide evidence for a fundamental assumption of this theory and provide a genetic basis for understanding the Red Queen dynamics in the Daphnia-Pasteuria system. PMID:26763092

  4. Adult Education and Social Sustainability: Harnessing the "Red Queen Effect"

    ERIC Educational Resources Information Center

    Easton, Peter

    2007-01-01

    In 1973, the evolutionary biologist Leigh Van Valen of the University of Chicago devised what he called the "Red Queen Effect" to describe the growth and development of species. It stipulated that an evolutionary system must continue to develop just to maintain its fitness relative to others evolving in its environment. The literary reference is…

  5. The geographic mosaic of sex and the Red Queen.

    PubMed

    King, Kayla C; Delph, Lynda F; Jokela, Jukka; Lively, Curtis M

    2009-09-15

    The maintenance of sexual reproduction in natural populations is a pressing question for evolutionary biologists. Under the "Red Queen" hypothesis, coevolving parasites reduce the reproductive advantage of asexual reproduction by adapting to infect clonal genotypes after they become locally common. In addition, the "geographic mosaic" theory of coevolution proposes that structured populations of interacting species can produce selection mosaics manifested as coevolutionary "hot spots" and "cold spots". Here, we tested whether a steep, habitat-specific cline in the frequency of sexual reproduction in a freshwater snail could be explained by the existence of hot spots and cold spots for coevolving parasites. We found that the shallow-water margins of lakes, where sexual reproduction is most common, are coevolutionary hot spots, and that deeper habitats are cold spots. These results are consistent with the geographic mosaic theory, in that the intensity of selection resulting from biological interactions can vary sharply in space. The results also support the Red Queen hypothesis, in that sex is associated with coevolutionary hot spots for virulent parasites. PMID:19631541

  6. Epidemiology of a Daphnia-Multiparasite System and Its Implications for the Red Queen

    PubMed Central

    Auld, Stuart K. J. R.; Hall, Spencer R.; Duffy, Meghan A.

    2012-01-01

    The Red Queen hypothesis can explain the maintenance of host and parasite diversity. However, the Red Queen requires genetic specificity for infection risk (i.e., that infection depends on the exact combination of host and parasite genotypes) and strongly virulent effects of infection on host fitness. A European crustacean (Daphnia magna) – bacterium (Pasteuria ramosa) system typifies such specificity and high virulence. We studied the North American host Daphnia dentifera and its natural parasite Pasteuria ramosa, and also found strong genetic specificity for infection success and high virulence. These results suggest that Pasteuria could promote Red Queen dynamics with D. dentifera populations as well. However, the Red Queen might be undermined in this system by selection from a more common yeast parasite (Metschnikowia bicuspidata). Resistance to the yeast did not correlate with resistance to Pasteuria among host genotypes, suggesting that selection by Metschnikowia should proceed relatively independently of selection by Pasteuria. PMID:22761826

  7. Running with the Red Queen: the role of biotic conflicts in evolution

    PubMed Central

    Brockhurst, Michael A.; Chapman, Tracey; King, Kayla C.; Mank, Judith E.; Paterson, Steve; Hurst, Gregory D. D.

    2014-01-01

    What are the causes of natural selection? Over 40 years ago, Van Valen proposed the Red Queen hypothesis, which emphasized the primacy of biotic conflict over abiotic forces in driving selection. Species must continually evolve to survive in the face of their evolving enemies, yet on average their fitness remains unchanged. We define three modes of Red Queen coevolution to unify both fluctuating and directional selection within the Red Queen framework. Empirical evidence from natural interspecific antagonisms provides support for each of these modes of coevolution and suggests that they often operate simultaneously. We argue that understanding the evolutionary forces associated with interspecific interactions requires incorporation of a community framework, in which new interactions occur frequently. During their early phases, these newly established interactions are likely to drive fast evolution of both parties. We further argue that a more complete synthesis of Red Queen forces requires incorporation of the evolutionary conflicts within species that arise from sexual reproduction. Reciprocally, taking the Red Queen's perspective advances our understanding of the evolution of these intraspecific conflicts. PMID:25355473

  8. How Complex, Probable, and Predictable is Genetically Driven Red Queen Chaos?

    PubMed

    Duarte, Jorge; Rodrigues, Carla; Januário, Cristina; Martins, Nuno; Sardanyés, Josep

    2015-12-01

    Coevolution between two antagonistic species has been widely studied theoretically for both ecologically- and genetically-driven Red Queen dynamics. A typical outcome of these systems is an oscillatory behavior causing an endless series of one species adaptation and others counter-adaptation. More recently, a mathematical model combining a three-species food chain system with an adaptive dynamics approach revealed genetically driven chaotic Red Queen coevolution. In the present article, we analyze this mathematical model mainly focusing on the impact of species rates of evolution (mutation rates) in the dynamics. Firstly, we analytically proof the boundedness of the trajectories of the chaotic attractor. The complexity of the coupling between the dynamical variables is quantified using observability indices. By using symbolic dynamics theory, we quantify the complexity of genetically driven Red Queen chaos computing the topological entropy of existing one-dimensional iterated maps using Markov partitions. Co-dimensional two bifurcation diagrams are also built from the period ordering of the orbits of the maps. Then, we study the predictability of the Red Queen chaos, found in narrow regions of mutation rates. To extend the previous analyses, we also computed the likeliness of finding chaos in a given region of the parameter space varying other model parameters simultaneously. Such analyses allowed us to compute a mean predictability measure for the system in the explored region of the parameter space. We found that genetically driven Red Queen chaos, although being restricted to small regions of the analyzed parameter space, might be highly unpredictable. PMID:26018821

  9. Red Queen Processes Drive Positive Selection on Major Histocompatibility Complex (MHC) Genes

    PubMed Central

    Ejsmond, Maciej Jan; Radwan, Jacek

    2015-01-01

    Major Histocompatibility Complex (MHC) genes code for proteins involved in the incitation of the adaptive immune response in vertebrates, which is achieved through binding oligopeptides (antigens) of pathogenic origin. Across vertebrate species, substitutions of amino acids at sites responsible for the specificity of antigen binding (ABS) are positively selected. This is attributed to pathogen-driven balancing selection, which is also thought to maintain the high polymorphism of MHC genes, and to cause the sharing of allelic lineages between species. However, the nature of this selection remains controversial. We used individual-based computer simulations to investigate the roles of two phenomena capable of maintaining MHC polymorphism: heterozygote advantage and host-pathogen arms race (Red Queen process). Our simulations revealed that levels of MHC polymorphism were high and driven mostly by the Red Queen process at a high pathogen mutation rate, but were low and driven mostly by heterozygote advantage when the pathogen mutation rate was low. We found that novel mutations at ABSs are strongly favored by the Red Queen process, but not by heterozygote advantage, regardless of the pathogen mutation rate. However, while the strong advantage of novel alleles increased the allele turnover rate, under a high pathogen mutation rate, allelic lineages persisted for a comparable length of time under Red Queen and under heterozygote advantage. Thus, when pathogens evolve quickly, the Red Queen is capable of explaining both positive selection and long coalescence times, but the tension between the novel allele advantage and persistence of alleles deserves further investigation. PMID:26599213

  10. Red Queen dynamics in multi-host and multi-parasite interaction system

    PubMed Central

    Rabajante, Jomar F.; Tubay, Jerrold M.; Uehara, Takashi; Morita, Satoru; Ebert, Dieter; Yoshimura, Jin

    2015-01-01

    In host-parasite systems, dominant host types are expected to be eventually replaced by other hosts due to the elevated potency of their specific parasites. This leads to changes in the abundance of both hosts and parasites exhibiting cycles of alternating dominance called Red Queen dynamics. Host-parasite models with less than three hosts and parasites have been demonstrated to exhibit Red Queen cycles, but natural host-parasite interactions typically involve many host and parasite types resulting in an intractable system with many parameters. Here we present numerical simulations of Red Queen dynamics with more than ten hosts and specialist parasites under the condition of no super-host nor super-parasite. The parameter region where the Red Queen cycles arise contracts as the number of interacting host and parasite types increases. The interplay between inter-host competition and parasite infectivity influences the condition for the Red Queen dynamics. Relatively large host carrying capacity and intermediate rates of parasite mortality result in never-ending cycles of dominant types. PMID:25899168

  11. Host-parasite Red Queen dynamics with phase-locked rare genotypes

    PubMed Central

    Rabajante, Jomar F.; Tubay, Jerrold M.; Ito, Hiromu; Uehara, Takashi; Kakishima, Satoshi; Morita, Satoru; Yoshimura, Jin; Ebert, Dieter

    2016-01-01

    Interactions between hosts and parasites have been hypothesized to cause winnerless coevolution, called Red Queen dynamics. The canonical Red Queen dynamics assume that all interacting genotypes of hosts and parasites undergo cyclic changes in abundance through negative frequency-dependent selection, which means that any genotype could become frequent at some stage. However, this prediction cannot explain why many rare genotypes stay rare in natural host-parasite systems. To investigate this, we build a mathematical model involving multihost and multiparasite genotypes. In a deterministic and controlled environment, Red Queen dynamics occur between two genotypes undergoing cyclic dominance changes, whereas the rest of the genotypes remain subordinate for long periods of time in phase-locked synchronized dynamics with low amplitude. However, introduction of stochastic noise in the model might allow the subordinate cyclic host and parasite types to replace dominant cyclic types as new players in the Red Queen dynamics. The factors that influence such evolutionary switching are interhost competition, specificity of parasitism, and degree of stochastic noise. Our model can explain, for the first time, the persistence of rare, hardly cycling genotypes in populations (for example, marine microbial communities) undergoing host-parasite coevolution. PMID:26973878

  12. Host-parasite Red Queen dynamics with phase-locked rare genotypes.

    PubMed

    Rabajante, Jomar F; Tubay, Jerrold M; Ito, Hiromu; Uehara, Takashi; Kakishima, Satoshi; Morita, Satoru; Yoshimura, Jin; Ebert, Dieter

    2016-03-01

    Interactions between hosts and parasites have been hypothesized to cause winnerless coevolution, called Red Queen dynamics. The canonical Red Queen dynamics assume that all interacting genotypes of hosts and parasites undergo cyclic changes in abundance through negative frequency-dependent selection, which means that any genotype could become frequent at some stage. However, this prediction cannot explain why many rare genotypes stay rare in natural host-parasite systems. To investigate this, we build a mathematical model involving multihost and multiparasite genotypes. In a deterministic and controlled environment, Red Queen dynamics occur between two genotypes undergoing cyclic dominance changes, whereas the rest of the genotypes remain subordinate for long periods of time in phase-locked synchronized dynamics with low amplitude. However, introduction of stochastic noise in the model might allow the subordinate cyclic host and parasite types to replace dominant cyclic types as new players in the Red Queen dynamics. The factors that influence such evolutionary switching are interhost competition, specificity of parasitism, and degree of stochastic noise. Our model can explain, for the first time, the persistence of rare, hardly cycling genotypes in populations (for example, marine microbial communities) undergoing host-parasite coevolution. PMID:26973878

  13. Asymmetric ecological conditions favor Red-Queen type of continued evolution over stasis

    PubMed Central

    Nordbotten, Jan Martin; Stenseth, Nils C.

    2016-01-01

    Four decades ago, Leigh Van Valen presented the Red Queen’s hypothesis to account for evolution of species within a multispecies ecological community [Van Valen L (1973) Evol Theory 1(1):1–30]. The overall conclusion of Van Valen’s analysis was that evolution would continue even in the absence of abiotic perturbations. Stenseth and Maynard Smith presented in 1984 [Stenseth NC, Maynard Smith J (1984) Evolution 38(4):870–880] a model for the Red Queen’s hypothesis showing that both Red-Queen type of continuous evolution and stasis could result from a model with biotically driven evolution. However, although that contribution demonstrated that both evolutionary outcomes were possible, it did not identify which ecological conditions would lead to each of these evolutionary outcomes. Here, we provide, using a simple, yet general population-biologically founded eco-evolutionary model, such analytically derived conditions: Stasis will predominantly emerge whenever the ecological system contains only symmetric ecological interactions, whereas both Red-Queen and stasis type of evolution may result if the ecological interactions are asymmetrical, and more likely so with increasing degree of asymmetry in the ecological system (i.e., the more trophic interactions, host–pathogen interactions, and the like there are [i.e., +/− type of ecological interactions as well as asymmetric competitive (−/−) and mutualistic (+/+) ecological interactions]). In the special case of no between-generational genetic variance, our results also predict dynamics within these types of purely ecological systems. PMID:26831108

  14. A queen pheromone induces workers to kill sexual larvae in colonies of the red imported fire ant (Solenopsis invicta).

    PubMed

    Klobuchar, Emily A; Deslippe, Richard J

    2002-07-01

    We conducted five bioassays to study how queens control the execution of sexual larvae by workers in colonies of the red imported fire ant, Solenopsis invicta. In each assay, subset colonies were made from many large polygyne colonies, and the 20 sexual larvae they contained were monitored over time. Sexual larvae mostly survived in queenless colonies, but were mostly killed in colonies with a single dealated queen, regardless of whether or not the queen was fertilized. The larvae were also killed when fresh corpses of queens were added to queenless colonies. Whereas acetone extracts of queens did not produce a significant increase in killings, extracts in buffered saline induced workers to execute most sexual larvae, indicating successful extraction of an execution pheromone. We identified the probable storage location of the chemical as the poison sac, and found both fresh (1 day) and old (21 day) extracts of poison sacs to be equally effective in inducing executions. The pheromone is stable at room temperature, perhaps because venom alkaloids also present in the extracts keep the pheromone from degrading. It is apparently either proteinaceous or associated with a proteinaceous molecule, a novel finding, as no queen pheromone of a proteinaceous nature has been previously demonstrated in ants. PMID:12216859

  15. A queen pheromone induces workers to kill sexual larvae in colonies of the red imported fire ant (Solenopsis invicta)

    NASA Astrophysics Data System (ADS)

    Klobuchar, Emily; Deslippe, Richard

    2002-05-01

    We conducted five bioassays to study how queens control the execution of sexual larvae by workers in colonies of the red imported fire ant, Solenopsis invicta. In each assay, subset colonies were made from many large polygyne colonies, and the 20 sexual larvae they contained were monitored over time. Sexual larvae mostly survived in queenless colonies, but were mostly killed in colonies with a single dealated queen, regardless of whether or not the queen was fertilized. The larvae were also killed when fresh corpses of queens were added to queenless colonies. Whereas acetone extracts of queens did not produce a significant increase in killings, extracts in buffered saline induced workers to execute most sexual larvae, indicating successful extraction of an execution pheromone. We identified the probable storage location of the chemical as the poison sac, and found both fresh (1 day) and old (21 day) extracts of poison sacs to be equally effective in inducing executions. The pheromone is stable at room temperature, perhaps because venom alkaloids also present in the extracts keep the pheromone from degrading. It is apparently either proteinaceous or associated with a proteinaceous molecule, a novel finding, as no queen pheromone of a proteinaceous nature has been previously demonstrated in ants.

  16. Volunteering as Red Queen Mechanism for Cooperation in Public Goods Games

    NASA Astrophysics Data System (ADS)

    Hauert, Christoph; De Monte, Silvia; Hofbauer, Josef; Sigmund, Karl

    2002-05-01

    The evolution of cooperation among nonrelated individuals is one of the fundamental problems in biology and social sciences. Reciprocal altruism fails to provide a solution if interactions are not repeated often enough or groups are too large. Punishment and reward can be very effective but require that defectors can be traced and identified. Here we present a simple but effective mechanism operating under full anonymity. Optional participation can foil exploiters and overcome the social dilemma. In voluntary public goods interactions, cooperators and defectors will coexist. We show that this result holds under very diverse assumptions on population structure and adaptation mechanisms, leading usually not to an equilibrium but to an unending cycle of adjustments (a Red Queen type of evolution). Thus, voluntary participation offers an escape hatch out of some social traps. Cooperation can subsist in sizable groups even if interactions are not repeated, defectors remain anonymous, players have no memory, and assortment is purely random.

  17. The role of biotic forces in driving macroevolution: beyond the Red Queen

    PubMed Central

    Voje, Kjetil L.; Holen, Øistein H.; Liow, Lee Hsiang; Stenseth, Nils Chr.

    2015-01-01

    A multitude of hypotheses claim that abiotic factors are the main drivers of macroevolutionary change. By contrast, Van Valen's Red Queen hypothesis is often put forward as the sole representative of the view that biotic forcing is the main evolutionary driver. This imbalance of hypotheses does not reflect our current knowledge: theoretical work demonstrates the plausibility of biotically driven long-term evolution, whereas empirical work suggests a central role for biotic forcing in macroevolution. We call for a more pluralistic view of how biotic forces may drive long-term evolution that is compatible with both phenotypic stasis in the fossil record and with non-constant extinction rates. Promising avenues of research include contrasting predictions from relevant theories within ecology and macroevolution, as well as embracing both abiotic and biotic proxies while modelling long-term evolutionary data. By fitting models describing hypotheses of biotically driven macroevolution to data, we could dissect their predictions and transcend beyond pattern description, possibly narrowing the divide between our current understanding of micro- and macroevolution. PMID:25948685

  18. Mode of transmission, host switching, and escape from the Red Queen by viviparous gyrodactylids (Monogenoidea).

    PubMed

    Boeger, Walter A; Kritsky, Delane C; Pie, Marcio R; Engers, Kerlen B

    2005-10-01

    Compared to other monogenoidean groups, viviparous gyrodactylids exhibit extraordinary species diversity and broad host range. It has been suggested that this evolutionary success is associated with a suite of morphological and life-history traits that include, in part, continuous transmission (i.e., ability to infect new hosts throughout the gyrodactylid life cycle). Experiments were conducted to explore the putative adaptive advantage of continuous transmission within viviparous gyrodactylids during colonization of new host resources. Differences in infrapopulation growth, such as abundance, prevalence, and duration of the infection, of Gyrodactylus anisopharynx on 3 species of fish--Corydoras paleatus and Corydoras ehrhardti (both natural hosts) as well as Corydoras schwartzi (a host not known to harbor G. anisopharynx)--held under isolated and grouped conditions were determined. Results showed that infrapopulations of G. anisopharynx on C. paleatus and C. schwartzi had higher growth when the parasite had the opportunity for host transfer (grouped hosts). Infrapopulations of G. anisopharynx on isolated and grouped C. ehrhardti showed an opposite trend, although differences in mean duration and maximum abundance were not statistically different. Results obtained from experiments with C. paleatus and C. schwartzi support the hypothesis that continuous transmission in viviparous gyrodactylids enhances colonization success, probably by allowing initial avoidance of Red Queen dynamics. The absence of statistical differences between infrapopulations on isolated and grouped C. ehrhardti suggests that parasite dynamics may be influenced by factors other than continuous transmission in this host. PMID:16419740

  19. The Big Rust and the Red Queen: Long-Term Perspectives on Coffee Rust Research.

    PubMed

    McCook, Stuart; Vandermeer, John

    2015-09-01

    Since 2008, there has been a cluster of outbreaks of the coffee rust (Hemileia vastatrix) across the coffee-growing regions of the Americas, which have been collectively described as the Big Rust. These outbreaks have caused significant hardship to coffee producers and laborers. This essay situates the Big Rust in a broader historical context. Over the past two centuries, coffee farmers have had to deal with the "curse of the Red Queen"-the need to constantly innovate in the face of an increasing range of threats, which includes the rust. Over the 20th century, particularly after World War II, national governments and international organizations developed a network of national, regional, and international coffee research institutions. These public institutions played a vital role in helping coffee farmers manage the rust. Coffee farmers have pursued four major strategies for managing the rust: bioprospecting for resistant coffee plants, breeding resistant coffee plants, chemical control, and agroecological control. Currently, the main challenge for researchers is to develop rust control strategies that are both ecologically and economically viable for coffee farmers, in the context of a volatile, deregulated coffee industry and the emergent challenges of climate change. PMID:26371395

  20. Eco-evolutionary feedback promotes Red Queen dynamics and selects for sex in predator populations.

    PubMed

    Haafke, Julia; Abou Chakra, Maria; Becks, Lutz

    2016-03-01

    Although numerous hypotheses exist to explain the overwhelming presence of sexual reproduction across the tree of life, we still cannot explain its prevalence when considering all inherent costs involved. The Red Queen hypothesis states that sex is maintained because it can create novel genotypes with a selective advantage. This occurs when the interactions between species induce frequent environmental change. Here, we investigate whether coevolution and eco-evolutionary feedback dynamics in a predator-prey system allows for indirect selection and maintenance of sexual reproduction in the predator. Combining models and chemostat experiments of a rotifer-algae system we show a continuous feedback between population and trait change along with recurrent shifts from selection by predation and competition for a limited resource. We found that a high propensity for sex was indirectly selected and was maintained in rotifer populations within environments containing these eco-evolutionary dynamics; whereas within environments under constant conditions, predators evolved rapidly to lower levels of sex. Thus, our results indicate that the influence of eco-evolutionary feedback dynamics on the overall evolutionary change has been underestimated. PMID:26899793

  1. The role of biotic forces in driving macroevolution: beyond the Red Queen.

    PubMed

    Voje, Kjetil L; Holen, Øistein H; Liow, Lee Hsiang; Stenseth, Nils Chr

    2015-06-01

    A multitude of hypotheses claim that abiotic factors are the main drivers of macroevolutionary change. By contrast, Van Valen's Red Queen hypothesis is often put forward as the sole representative of the view that biotic forcing is the main evolutionary driver. This imbalance of hypotheses does not reflect our current knowledge: theoretical work demonstrates the plausibility of biotically driven long-term evolution, whereas empirical work suggests a central role for biotic forcing in macroevolution. We call for a more pluralistic view of how biotic forces may drive long-term evolution that is compatible with both phenotypic stasis in the fossil record and with non-constant extinction rates. Promising avenues of research include contrasting predictions from relevant theories within ecology and macroevolution, as well as embracing both abiotic and biotic proxies while modelling long-term evolutionary data. By fitting models describing hypotheses of biotically driven macroevolution to data, we could dissect their predictions and transcend beyond pattern description, possibly narrowing the divide between our current understanding of micro- and macroevolution. PMID:25948685

  2. Red queen dynamics and the evolution of translational redundancy and degeneracy

    NASA Astrophysics Data System (ADS)

    Krakauer, David C.; Jansen, Vincent A. A.; Nowak, Martin

    We explore adaptive theories for the diversity of protein translation based on the genetic code viewed as a primitive immune system. Immunity is acquired through a genetic mechanism of non-recognition of parasite genomes. Modifying the set of codons bound by tRNA anticodon molecules or changing the specificity of binding, reduces the replication rate of translational parasites such as viruses. Changing the binding specifity can be thought of in terms of varying degrees of redundancy an d degeneracy. Redundancy in the genetic code is commonly attributed to using a four base triplet mechanism to encode the 20 amino acids. This has been referred to as synonym redundancy. There are however at least a further two forms of redundancy associated with the code and one source of degeneracy. A first form of redundancy arises from decoding all 61 possible sense codons using fewer than 61 anticodons. Such a strategy involves reduced binding specificity. A second source of redundancy is present in the multiplicity of copies of each unique tRNA (tRNA copy redundancy). Degeneracy arises when different anticodons become associated with a single amino acid to increase specificity. Variation in these strategies across taxa ensures that the translational machinery is diverse whereas the code remains approximately constant. We construct a red queen theory for translational diversity: a theory in which host translational strategies - as defined by the degree of redundancy or degeneracy of anticodons - are const antly shifting through time to evade parasitism but where neither parasite nor host gains a systematic advantage.

  3. Hidden suppression of sex ratio distortion suggests Red queen dynamics between Wolbachia and its dwarf spider host.

    PubMed

    Vanthournout, B; Hendrickx, F

    2016-08-01

    Genetic conflict theory predicts strong selection for host nuclear factors suppressing endosymbiont effects on reproduction; however, evidence of these suppressors is currently scarce. This can either be caused by a low suppressor evolution rate, or if suppressors originate frequently, by rapid spread and concurrent masking of their activity by silencing the endosymbiont effect. To explore this, we use two populations of a dwarf spider with a similar female bias, caused by a Wolbachia infection. Using inter- and intrapopulation crosses, we determine that one of these populations demonstrates a higher suppressing capability towards Wolbachia despite having a similar population sex ratio. This suggests that spider and endosymbiont are locked in so-called red queen dynamics where, despite continuous coevolution, average fitness remains the same, hence hiding the presence of the suppressor. Finding different suppressor activity in populations that even lack phenotypic differentiation (i.e. similar sex ratio) further supports the hypothesis that suppressors originate often, but are often hidden by their own mode of action by countering endosymbiont effects. PMID:26995349

  4. The Red Queen and the seed bank: pathogen resistance of ex situ and in situ conserved barley

    PubMed Central

    Jensen, Helen R; Dreiseitl, Antonín; Sadiki, Mohammed; Schoen, Daniel J

    2012-01-01

    Plant geneticists have proposed that the dynamic conservation of crop plants in farm environments (in situ conservation) is complementary to static conservation in seed banks (ex situ conservation) because it may help to ensure adaptation to changing conditions. Here, we test whether collections of a traditional variety of Moroccan barley (Hordeum vulgare ssp. vulgare) conserved ex situ showed differences in qualitative and quantitative resistance to the endemic fungal pathogen, Blumeria graminis f.sp. hordei, compared to collections that were continuously cultivated in situ. In detached-leaf assays for qualitative resistance, there were some significant differences between in situ and ex situ conserved collections from the same localities. Some ex situ conserved collections showed lower resistance levels, while others showed higher resistance levels than their in situ conserved counterparts. In field trials for quantitative resistance, similar results were observed, with the highest resistance observed in situ. Overall, this study identifies some cases where the Red Queen appears to drive the evolution of increased resistance in situ. However, in situ conservation does not always result in improved adaptation to pathogen virulence, suggesting a more complex evolutionary scenario, consistent with several published examples of plant–pathogen co-evolution in wild systems. PMID:25568056

  5. Identification, expression, and immuno-reactivity of Sol i 2 & Sol i 4 venom proteins of queen red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae).

    PubMed

    Lockwood, Stephanie A; Haghipour-Peasley, Jilla; Hoffman, Donald R; Deslippe, Richard J

    2012-10-01

    We report on two low-molecular weight proteins that are stored in the venom of queen red imported fire ants (Solenopsis invicta). Translated amino acid sequences identified one protein to have 74.8% identity with the Sol i 2w worker allergen, and the other protein was found to have 96/97% identity with Sol i 4.01w/4.02w worker allergens. Both Sol i 2 and Sol i 4 queen and worker proteins were expressed using pEXP1-DEST vector in SHuffle™ T7 Express lysY Escherichia coli. Proteins were expressed at significant concentrations, as opposed to the μg/ml amounts by our previous expression methods, enabling further study of these proteins. Sol i 2q protein bound weakly to human IgE, sera pooled from allergic patients, whereas Sol i 2w, Sol i 4.01w, and Sol i 4q proteins bound strongly. Despite Sol i 2w and Sol i 2q proteins having 74.8% identity, the queen protein is less immuno-reactive than the worker allergen. This finding is consistent with allergic individuals being less sensitive to queen than worker venom. PMID:22683679

  6. The Red Queen Model of Recombination Hotspots Evolution in the Light of Archaic and Modern Human Genomes

    PubMed Central

    Lesecque, Yann; Glémin, Sylvain; Lartillot, Nicolas; Mouchiroud, Dominique; Duret, Laurent

    2014-01-01

    Recombination is an essential process in eukaryotes, which increases diversity by disrupting genetic linkage between loci and ensures the proper segregation of chromosomes during meiosis. In the human genome, recombination events are clustered in hotspots, whose location is determined by the PRDM9 protein. There is evidence that the location of hotspots evolves rapidly, as a consequence of changes in PRDM9 DNA-binding domain. However, the reasons for these changes and the rate at which they occur are not known. In this study, we investigated the evolution of human hotspot loci and of PRDM9 target motifs, both in modern and archaic human lineages (Denisovan) to quantify the dynamic of hotspot turnover during the recent period of human evolution. We show that present-day human hotspots are young: they have been active only during the last 10% of the time since the divergence from chimpanzee, starting to be operating shortly before the split between Denisovans and modern humans. Surprisingly, however, our analyses indicate that Denisovan recombination hotspots did not overlap with modern human ones, despite sharing similar PRDM9 target motifs. We further show that high-affinity PRDM9 target motifs are subject to a strong self-destructive drive, known as biased gene conversion (BGC), which should lead to the loss of the majority of them in the next 3 MYR. This depletion of PRDM9 genomic targets is expected to decrease fitness, and thereby to favor new PRDM9 alleles binding different motifs. Our refined estimates of the age and life expectancy of human hotspots provide empirical evidence in support of the Red Queen hypothesis of recombination hotspots evolution. PMID:25393762

  7. The red queen model of recombination hotspots evolution in the light of archaic and modern human genomes.

    PubMed

    Lesecque, Yann; Glémin, Sylvain; Lartillot, Nicolas; Mouchiroud, Dominique; Duret, Laurent

    2014-11-01

    Recombination is an essential process in eukaryotes, which increases diversity by disrupting genetic linkage between loci and ensures the proper segregation of chromosomes during meiosis. In the human genome, recombination events are clustered in hotspots, whose location is determined by the PRDM9 protein. There is evidence that the location of hotspots evolves rapidly, as a consequence of changes in PRDM9 DNA-binding domain. However, the reasons for these changes and the rate at which they occur are not known. In this study, we investigated the evolution of human hotspot loci and of PRDM9 target motifs, both in modern and archaic human lineages (Denisovan) to quantify the dynamic of hotspot turnover during the recent period of human evolution. We show that present-day human hotspots are young: they have been active only during the last 10% of the time since the divergence from chimpanzee, starting to be operating shortly before the split between Denisovans and modern humans. Surprisingly, however, our analyses indicate that Denisovan recombination hotspots did not overlap with modern human ones, despite sharing similar PRDM9 target motifs. We further show that high-affinity PRDM9 target motifs are subject to a strong self-destructive drive, known as biased gene conversion (BGC), which should lead to the loss of the majority of them in the next 3 MYR. This depletion of PRDM9 genomic targets is expected to decrease fitness, and thereby to favor new PRDM9 alleles binding different motifs. Our refined estimates of the age and life expectancy of human hotspots provide empirical evidence in support of the Red Queen hypothesis of recombination hotspots evolution. PMID:25393762

  8. The Red Queen in a potato field: integrated pest management versus chemical dependency in Colorado potato beetle control.

    PubMed

    Alyokhin, Andrei; Mota-Sanchez, David; Baker, Mitchell; Snyder, William E; Menasha, Sandra; Whalon, Mark; Dively, Galen; Moarsi, Wassem F

    2015-03-01

    Originally designed to reconcile insecticide applications with biological control, the concept of integrated pest management (IPM) developed into the systems-based judicious and coordinated use of multiple control techniques aimed at reducing pest damage to economically tolerable levels. Chemical control, with scheduled treatments, was the starting point for most management systems in the 1950s. Although chemical control is philosophically compatible with IPM practices as a whole, reduction in pesticide use has been historically one of the main goals of IPM practitioners. In the absence of IPM, excessive reliance on pesticides has led to repeated control failures due to the evolution of resistance by pest populations. This creates the need for constant replacement of failed chemicals with new compounds, known as the 'insecticide treadmill'. In evolutionary biology, a similar phenomenon is known as the Red Queen principle - continuing change is needed for a population to persevere because its competitors undergo constant evolutionary adaptation. The Colorado potato beetle, Leptinotarsa decemlineata (Say), is an insect defoliator of potatoes that is notorious for its ability to develop insecticide resistance. In the present article, a review is given of four case studies from across the United States to demonstrate the importance of using IPM for sustainable management of a highly adaptable insect pest. Excessive reliance on often indiscriminate insecticide applications and inadequate use of alternative control methods, such as crop rotation, appear to expedite evolution of insecticide resistance in its populations. Resistance to IPM would involve synchronized adaptations to multiple unfavorable factors, requiring statistically unlikely genetic changes. Therefore, integrating different techniques is likely to reduce the need for constant replacement of failed chemicals with new ones. PMID:24817433

  9. Strange stars

    NASA Technical Reports Server (NTRS)

    Alcock, Charles; Farhi, Edward; Olinto, Angela

    1986-01-01

    Strange matter, a form of quark matter that is postulated to be absolute stable, may be the true ground stage of the hadrons. If this hypothesis is correct, neutron stars may convert to 'strange stars'. The mass-radius relation for strange stars is very different from that of neutron stars; there is no minimum mass, and for mass of 1 solar mass or less, mass is proportional to the cube of the radius. For masses between 1 solar mass and 2 solar masses, the radii of strange stars are about 10 km, as for neutron stars. Strange stars may have an exposed quark surface, which is capable of radiating at rates greatly exceeding the Eddington limit, but has a low emissivity for X-ray photons. The stars may have a thin crust with the same composition as the preneutron drip outer layer of a conventional neutron star crust. Strange stars cool efficiently via neutrino emission.

  10. Drama queens.

    PubMed

    Taylor, J

    1998-01-01

    Abstract Why is it that many 'lesbian playwrights' are unwilling to define themselves as such? "Drama Queens: Ruling with a Rod of Irony" attempts to answer this question and to discover what the term 'lesbian playwright' means within contemporary culture. It dissects the dominant homophobic and misogynist mythologies that have outlawed 'queer' girl writers to the underskirts of British theatre, and ultimately denied them either artistic or commercial currency. It examines the history of the label in the context of feminism, gay liberation and positive representation, and queries its aesthetic and economic viability in a climate where the 'lesbian playwright' is not even supported by her own community. Finally, it is an exploration into radical forms, working methodologies and new genres stimulated by being neither semantic Man nor Woman. It is a piece about cultural terrorism-and how to avoid capture. PMID:24785519

  11. The Eight Queens Problem.

    ERIC Educational Resources Information Center

    Olson, Alton T.

    1993-01-01

    Presents a series of solution methods to the Eight Queens Problem of placing eight queens on a chess board so that no one queen can capture another. Solution methods progress from empirical approaches to the use of computer algorithms. Geometric transformations are used to find other solutions. (MDH)

  12. 14. Hell Gate Bridge south abutment tower. Queens, Queens Co., ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Hell Gate Bridge south abutment tower. Queens, Queens Co., NY. Sec. 4207, MP 7.29. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  13. Strangeness in the Nucleon

    SciTech Connect

    Dahiya, Harleen; Gupta, Manmohan

    2007-10-03

    There are several different experimental indications, such as the {sigma}{sub {pi}}{sub N} term, strange spin polarization, strangeness contribution to the magnetic moment of the proton, ratio of strange and non strange quark flavor distributions which suggest that the nucleon contains a hidden strangeness component which is contradictory to the naive constituent quark model. Chiral constituent quark model with configuration mixing ({chi}CQM{sub config}) is known to provide a satisfactory explanation of the ''proton spin problem'' and related issues. In the present work, we have extended the model to carry out the calculations for the parameters pertaining to the strange quark content of the nucleon, for example, the strange spin polarization {delta}s, strange components of the weak axial vector form factors {delta}{sigma} and {delta}{sub 8} as well as F and D, strangeness magnetic moment of the proton {mu}{sub p}{sup s}, the strange quark content in the nucleon f{sub s} coming from the {sigma}{sub {pi}}{sub N} term, the ratios between strange and non-strange quarks (2s/u+d) and (2s/u-bar+d), contribution of strangeness to angular momentum sum rule etc. Our result demonstrates the broad consistency with the experimental observations as well as other theoretical considerations.

  14. 'Snow Queen' Animation

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This animation consists of two close-up images of 'Snow Queen,' taken several days apart, by the Robotic Arm Camera (RAC) aboard NASA's Phoenix Mars Lander.

    Snow Queen is the informal name for a patch of bright-toned material underneath the lander.

    Thruster exhaust blew away surface soil covering Snow Queen when Phoenix landed on May 25, 2008, exposing this hard layer comprising several smooth rounded cavities beneath the lander. The RAC images show how Snow Queen visibly changed between June 15, 2008, the 21st Martian day, or sol, of the mission and July 9, 2008, the 44th sol.

    Cracks as long as 10 centimeters (about four inches) appeared. One such crack is visible at the left third and the upper third of the Sol 44 image. A seven millimeter (one-third inch) pebble or clod appears just above and slightly to the right of the crack in the Sol 44 image. Cracks also appear in the lower part of the left third of the image. Other pieces noticeably shift, and some smooth texture has subtly roughened.

    The Phoenix team carefully positioned and focused RAC the same way in both images. Each image is about 60 centimeters, or about two feet, wide. The object protruding in from the top on the right half of the images is Phoenix's thermal and electrical conductivity probe.

    Snow Queen and other ice exposed by Phoenix landing and trenching operations on northern polar Mars is the first time scientists have been able to monitor Martian ice at a place where temperatures are cold enough that the ice doesn't immediately sublimate, or vaporize, away.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  15. Strange Quark Star Crusts

    SciTech Connect

    Steiner, Andrew W.

    2007-02-27

    If strange quark matter is absolutely stable, some neutron stars may be strange quark stars. Strange quark stars are usually assumed to have a simple liquid surface. We show that if the surface tension of droplets of quark matter in the vacuum is sufficiently small, droplets of quark matter on the surface of a strange quark star may form a solid crust on top of the strange quark star. This solid crust can significantly modify the predictions for the photon emission for the surface in an observable way.

  16. Strange Light Nuclei

    SciTech Connect

    Nakamura, Satoshi N.

    2014-04-01

    "Strange" means 1) unusual or surprising, especially in a way that is difficult to explain or understand or 2) having strangeness degree of freedom. Light nuclear systems with strangeness, light hypernuclei, are perfect playground to study baryon force which would be a bridge between well established nuclear force in low energy region and QCD, the first principle of the strong interaction. Overview of study of light hypernuclei is given and recent experimental findings are reviewed.

  17. [The oral problems of queen Elizabeth I].

    PubMed

    Eijkman, M A J

    2012-05-01

    Queen Elizabeth I of England (1533-1603), probably the most famous English Queen ever, had persistent oral problems. Her oral problems were so serious that they probably hampered the Queen in the performance of her tasks. PMID:22667195

  18. The physics of strange matter

    SciTech Connect

    Olinto, A.V. |

    1991-12-01

    Strange matter may be the ground state of matter. We review the phenomenology and astrophysical implications of strange matter, and discuss the possible ways for testing the strange matter hypothesis.

  19. 13. New York Connecting RR: Hell Gate Bridge. Queens, Queens ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. New York Connecting RR: Hell Gate Bridge. Queens, Queens Co., NY. Sec. 4207, MP 7.29. (See HAER No. NY-88 for further documentation on this site). - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  20. 11. New York Connecting RR: Hell Gate Bridge. Queens, Queens ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. New York Connecting RR: Hell Gate Bridge. Queens, Queens Co., NY. Sec. 4207, MP 7.29. (See HAER No. NY-88 for further documentation on this site). - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  1. 12. New York Connecting RR: Hell Gate Bridge. Queens, Queens ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. New York Connecting RR: Hell Gate Bridge. Queens, Queens Co., NY. Sec. 4207, MP 7.29. (See HAER No. NY-88 for further documentation on this site). - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  2. The Red Queen Visits Minkowski Space

    ERIC Educational Resources Information Center

    Low, Robert J.

    2007-01-01

    When Alice went "Through the Looking Glass", she found herself in a situation where she had to run as fast as she could in order to stay still. In accordance with the dictum that truth is stranger than fiction, we will see that it is possible to find a situation in special relativity where running towards one's target is actually…

  3. Strange Nonchaotic Stars

    NASA Astrophysics Data System (ADS)

    Lindner, John F.; Kohar, Vivek; Kia, Behnam; Hippke, Michael; Learned, John G.; Ditto, William L.

    2015-02-01

    The unprecedented light curves of the Kepler space telescope document how the brightness of some stars pulsates at primary and secondary frequencies whose ratios are near the golden mean, the most irrational number. A nonlinear dynamical system driven by an irrational ratio of frequencies generically exhibits a strange but nonchaotic attractor. For Kepler's "golden" stars, we present evidence of the first observation of strange nonchaotic dynamics in nature outside the laboratory. This discovery could aid the classification and detailed modeling of variable stars.

  4. [Through strangeness to oneself].

    PubMed

    Sorgedrager, D B

    1993-11-01

    "Being strange" as opposed to "being oneself" is part of the thinking in all cultures. Belonging to a given culture is actually defined by ones identity and by "being oneself". Both concepts--"being oneself" or "being strange"--are rational and related constructs. Whatever they are confronted with, for most human beings it is self-evident to differentiate between subject and object, between "being oneself" or "being strange". This explains why thinking often occurs in opposites or polarities, as an either/or. All "being strange" has its origins in one's own self. "Being strange" becomes most obvious when persons, gestalt or cultures strongly deviate from one's own familiar situation. It is part of man's disposition to be cautious, suspicious of and at distance from everything considered strange and different. That explains his xenophobia feelings and actions. Behind this attitude we can always discover one's wish to preserve the familiar beliefs--combined with an uneasiness to give up one's thinking and behaviour that is proven and routine. It is only by reflecting on our own culture and our own inheritance that we have the possibility to come to terms with our own ethnic identity and foreign behavioral patterns. If we do not try to understand other cultures while keeping our own cultural identity, tensions and violent conflicts will inevitably result. PMID:8278564

  5. Queen reproductive state modulates pheromone production and queen-worker interactions in honeybees

    PubMed Central

    Kocher, Sarah D.; Richard, Freddie-Jeanne; Tarpy, David R.

    2009-01-01

    The mandibular glands of queen honeybees produce a pheromone that modulates many aspects of worker honeybee physiology and behavior and is critical for colony social organization. The exact chemical blend produced by the queen differs between virgin and mated, laying queens. Here, we investigate the role of mating and reproductive state on queen pheromone production and worker responses. Virgin queens, naturally mated queens, and queens instrumentally inseminated with either semen or saline were collected 2 days after mating or insemination. Naturally mated queens had the most activated ovaries and the most distinct chemical profile in their mandibular glands. Instrumentally inseminated queens were intermediate between virgins and naturally mated queens for both ovary activation and chemical profiles. There were no significant differences between semen- and saline-inseminated queens. Workers were preferentially attracted to the mandibular gland extracts from queens with significantly more activated ovaries. These studies suggest that the queen pheromone blend is modulated by the reproductive status of the queens, and workers can detect these subtle differences and are more responsive to queens with higher reproductive potential. Furthermore, it appears as if insemination substance does not strongly affect physiological characteristics of honeybee queens 2 days after insemination, suggesting that the insemination process or volume is responsible for stimulating these early postmating changes in honeybee queens. PMID:22476212

  6. Strange nonchaotic stars.

    PubMed

    Lindner, John F; Kohar, Vivek; Kia, Behnam; Hippke, Michael; Learned, John G; Ditto, William L

    2015-02-01

    The unprecedented light curves of the Kepler space telescope document how the brightness of some stars pulsates at primary and secondary frequencies whose ratios are near the golden mean, the most irrational number. A nonlinear dynamical system driven by an irrational ratio of frequencies generically exhibits a strange but nonchaotic attractor. For Kepler's "golden" stars, we present evidence of the first observation of strange nonchaotic dynamics in nature outside the laboratory. This discovery could aid the classification and detailed modeling of variable stars. PMID:25699444

  7. Strangeness at SIS energies

    SciTech Connect

    Koch, Volker

    2005-09-28

    In this contribution the authors discuss the physics of strange hadrons in low energy ({approx_equal} 1-2 AGeV) heavy ion collision. In this energy range the relevant strange particle are the kaons and anti-kaons. The most interesting aspect concerning these particles are so called in-medium modifications. They will attempt to review the current status of understanding of these in medium modifications. In addition they briefly discuss other issues related with kaon production, such as the nuclear equation of state and chemical equilibrium.

  8. Host manipulation of bumble bee queens by Sphaerularia nematodes indirectly affects foraging of non-host workers.

    PubMed

    Kadoya, Eri Z; Ishii, Hiroshi S

    2015-05-01

    Sphaerularia bombi Dufour is a major parasite of bumble bee queens that manipulates its host's behavior: parasitized queens do not breed and found nests but continue to fly into the early summer months. We examined the indirect consequences of this host manipulation on non-host workers in central Hokkaido Island, Japan. In this area, parasitism of Bombus terrestris by S. bombi is common but does not affect every queen; therefore, as summer begins, B. terrestris queens continue to dominate some flower patches and disappear from others. At sites dominated by parasitized queens, we found that the nectar standing crop of red clover was smaller, B. terrestris workers carried out fewer legitimate visits to red clover and more nectar robberies, and the workers were smaller than at other sites. Removing queens from a site increased the nectar standing crop of red clover, the frequency of worker visits to red clover, and the size of the workers. These results suggest that host manipulation by S. bombi increased competition for flower resources among host queens and non-host workers and altered the interaction between plants and non-host flower visitors. PMID:26236849

  9. Two alternative versions of strangeness

    PubMed Central

    Nishijima, Kazuhikoa

    2008-01-01

    The concept of strangeness emerged from the low energy phenomenology before the entry of quarks in particle physics. The connection between strangeness and isospin is rather accidental and loose and we recognize later that the definition of strangeness is model-dependent. Indeed, in Gell-Mann’s triplet quark model we realize that there is a simple alternative representation of strangeness. When the concept of generations is incorporated into the quark model we find that only the second alternative version of strangeness remains meaningful, whereas the original one does no longer keep its significance. PMID:18997448

  10. Strange Nonchaotic Stars

    NASA Astrophysics Data System (ADS)

    Lindner, John F.; Kohar, Vivek; Kia, Behnam; Hippke, Michael; Learned, John G.; Ditto, William L.

    2015-08-01

    Exploiting the unprecedented capabilities of the planet-hunting Kepler space telescope, which stared at 150 000 stars for four years, we discuss recent evidence that certain stars dim and brighten in complex patterns with fractal features. Such stars pulsate at primary and secondary frequencies whose ratios are near the famous golden mean, the most irrational number. A nonlinear system driven by an irrational ratio of frequencies is generically attracted toward a “strange” behavior that is geometrically fractal without displaying the “butterfly effect” of chaos. Strange nonchaotic attractors have been observed in laboratory experiments and have been hypothesized to describe the electrochemical activity of the brain, but a bluish white star 16 000 light years from Earth in the constellation Lyra may manifest, in the scale-free distribution of its minor frequency components, the first strange nonchaotic attractor observed in the wild. The recognition of stellar strange nonchaotic dynamics may improve the classification of these stars and refine the physical modeling of their interiors. We also discuss nonlinear analysis of other RR Lyrae stars in Kepler field of view and discuss some toy models for modeling these stars.References: 1) Hippke, Michael, et al. "Pulsation period variations in the RRc Lyrae star KIC 5520878." The Astrophysical Journal 798.1 (2015): 42.2) Lindner, John F., et al. "Strange nonchaotic stars." Phys. Rev. Lett. 114, 054101 (2015)

  11. 'Queen of Hearts' Oakleaf Hydrangea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A late-blooming oakleaf hydrangea (Hydrangea quercifolia) cultivar was released by the U.S. National Arboretum. ‘Queen of Hearts’ has grown 6.5 feet high and 11 feet wide in 11 years. In early summer, it is covered with 11-inch-long inflorescences that are held upright above the foliage. Flowers ...

  12. Multiply Strange Nuclear Systems

    NASA Astrophysics Data System (ADS)

    Schaffner, J.; Dover, C. B.; Gal, A.; Greiner, C.; Millener, D. J.; Stocker, H.

    1994-10-01

    We investigate the stability of multiply strange baryonic systems, in the context of a mean field approach obtained from an underlying set of phenomenological meson-baryon interactions. The coupling parameters which determine the conventional σ + ω mean fields (Hartree potentials) seen by various baryon species (N, Λ, Ξ) in the many-body system are constrained by reproducing the trend of observed binding energies of single particle (N, Λ, Ξ) states, as well as the energy per particle and density of non-strange nuclear matter. We also consider additional scalar (σ*) and vector (φ) fields which couple strongly to strange baryons. The couplings of these fields are adjusted to produce strong hyperon-hyperon interactions, as suggested by the data on ΛΛ hypernuclei. Extrapolating this approach to systems of large strangeness S, we find a broad class of objects composed of neutrons, protons, Λ‧s and Ξ‧s, which are stable against strong decay. In these systems, the presence of filled Λ orbitals blocks the strong decay ΞN → ΛΛ, leading to a strangeness fraction fs = |S|/A ≍1, density ρ ≍ (2 - 3) ρ0, and charge fraction fq in the range - 0.1 strange quark matter ("stranglets"), but with a low binding energy per particle EB/A ≍ -10 to -20 MeV. We compare with an approximate mass formula which qualitatively describes the results of the mean field calculations. Such weakly bound multi-strange objects can be stable for very large A, unlike ordinary nuclei, since the Coulomb repulsion generated by the protons is largely cancelled by the presence of a comparable number of Ξ‧s, leading to a small net charge (positive or negative) of order A1/3. We comment on the weak decays of such subjects and the possibility of their production in relativistic heavy ion collisions.

  13. Neonicotinoid pesticides severely affect honey bee queens.

    PubMed

    Williams, Geoffrey R; Troxler, Aline; Retschnig, Gina; Roth, Kaspar; Yañez, Orlando; Shutler, Dave; Neumann, Peter; Gauthier, Laurent

    2015-01-01

    Queen health is crucial to colony survival of social bees. Recently, queen failure has been proposed to be a major driver of managed honey bee colony losses, yet few data exist concerning effects of environmental stressors on queens. Here we demonstrate for the first time that exposure to field-realistic concentrations of neonicotinoid pesticides during development can severely affect queens of western honey bees (Apis mellifera). In pesticide-exposed queens, reproductive anatomy (ovaries) and physiology (spermathecal-stored sperm quality and quantity), rather than flight behaviour, were compromised and likely corresponded to reduced queen success (alive and producing worker offspring). This study highlights the detriments of neonicotinoids to queens of environmentally and economically important social bees, and further strengthens the need for stringent risk assessments to safeguard biodiversity and ecosystem services that are vulnerable to these substances. PMID:26459072

  14. Neonicotinoid pesticides severely affect honey bee queens

    PubMed Central

    Williams, Geoffrey R.; Troxler, Aline; Retschnig, Gina; Roth, Kaspar; Yañez, Orlando; Shutler, Dave; Neumann, Peter; Gauthier, Laurent

    2015-01-01

    Queen health is crucial to colony survival of social bees. Recently, queen failure has been proposed to be a major driver of managed honey bee colony losses, yet few data exist concerning effects of environmental stressors on queens. Here we demonstrate for the first time that exposure to field-realistic concentrations of neonicotinoid pesticides during development can severely affect queens of western honey bees (Apis mellifera). In pesticide-exposed queens, reproductive anatomy (ovaries) and physiology (spermathecal-stored sperm quality and quantity), rather than flight behaviour, were compromised and likely corresponded to reduced queen success (alive and producing worker offspring). This study highlights the detriments of neonicotinoids to queens of environmentally and economically important social bees, and further strengthens the need for stringent risk assessments to safeguard biodiversity and ecosystem services that are vulnerable to these substances. PMID:26459072

  15. Strange stars, strange dwarfs, and planetary-like strange-matter objects

    SciTech Connect

    Weber, F.; Schaab, C.; Weigel, M.K.; Glendenning, N.K.

    1995-05-01

    This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts--neutron stars and white dwarfs--their properties are determined by two (rather than one) parameters, the central star density and the density at the base of the nuclear crust. This leads to stellar strange-matter configurations whose properties are much more complex than those of the conventional sequence. As an example, two generically different categories of stable strange dwarfs are found, which could be the observed white dwarfs. Furthermore the authors find very-low-mass strange stellar objects, with masses as small as those of Jupiter or even lighter planets. Such objects, if abundant enough, should be seen by the presently performed gravitational microlensing searches.

  16. Effect of irradiation on queen survivorship and reproduction in the invasive fire ant Solenopsis invicta,(Hymenoptera: Formicidae) and a generic phytosanitary irradiation dose for ants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ants are common hitchhiker pests on traded agricultural commodities that could be controlled by postharvest irradiation treatment. We studied radiation tolerance in queens of the red imported fire ant Solenopsis invicta Buren to determine the dose sufficient for its control. Virgin or fertile queens...

  17. Strange skyrmion molecules

    NASA Astrophysics Data System (ADS)

    Kopeliovich, Vladimir B.; Stern, Boris E.

    1997-05-01

    Composed skyrmions with B=2, strangeness content close to 0.5 and the binding energy of several tens of Mev are described. These skyrmions are obtained starting from the system of two B=1 hedgehogs located in different SU(2) subgroups of SU(3) and have the mass and baryon number distribution of molecular (dipole) type. The quantization of zero modes of skyrmion molecules and physics consequences of their existence are discussed.

  18. Strange skyrmion molecules

    SciTech Connect

    Kopeliovich, Vladimir B.; Stern, Boris E.

    1997-05-20

    Composed skyrmions with B=2, strangeness content close to 0.5 and the binding energy of several tens of Mev are described. These skyrmions are obtained starting from the system of two B=1 hedgehogs located in different SU(2) subgroups of SU(3) and have the mass and baryon number distribution of molecular (dipole) type. The quantization of zero modes of skyrmion molecules and physics consequences of their existence are discussed.

  19. Strange stars at finite temperature

    NASA Astrophysics Data System (ADS)

    Ray, Subharthi; Bagchi, Manjari; Dey, Jishnu; Dey, Mira

    2006-03-01

    We calculate strange star properties, using large Nc approximation with built-in chiral symmetry restoration (CSM). We used a relativistic Hartree Fock meanfield approximation method, using a modi.ed Richardson potential with two scale parameters Λ and Λ', to find a new set of equation of state (EOS) for strange quark matter. We take the effect of temperature (T) on gluon mass, in addition to the usual density dependence, and find that the transition T from hadronic matter to strange matter is 80 MeV. Therefore formation of strange stars may be the only signal for formation of QGP with asymptotic freedom (AF) and CSM.

  20. Is the Strange Situation Too Strange for Japanese Infants?

    ERIC Educational Resources Information Center

    Ujiie, Tastuo

    The applicability of the Strange Situation procedure and the ABC typology for Japanese infants is discussed by examining data from studies in which the Strange Situation procedure was performed with Japanese infants. Findings of a study conducted in Sapporo, Japan, are discussed and their implications are pointed out. The discussion concludes that…

  1. Acceptance of mated Queens and Queen Cells in Colonies of Russian and Italian Honey Bees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Requeening colonies is a standard beekeeping practice with both mated queens and queen cells. More beekeepers are requeening with Russian honey bees queens because of their significantly higher resistance to varroa and tracheal mites, their good honey production and their overwintering abilities. ...

  2. Strange experiments at the AGS

    SciTech Connect

    Chrien, R.

    1990-01-01

    The purpose of this review is to report recent progress in nuclear experiments involving strangeness which have been carried out at the Brookhaven Alternating Gradient Synchrotron over the past three years. These recent developments are noted in three areas: few body systems and dibaryons; strange probes of the nucleus; and associated production of hypernuclei. 9 refs., 3 figs.

  3. Electroproduction of Strange Nuclei

    SciTech Connect

    E.V. Hungerford

    2002-06-01

    The advent of high-energy, CW-beams of electrons now allows electro-production and precision studies of nuclei containing hyperons. Previously, the injection of strangeness into a nucleus was accomplished using secondary beams of mesons, where beam quality and target thickness limited the missing mass resolution. We review here the theoretical description of the (e, e'K+) reaction mechanism, and discuss the first experiment demonstrating that this reaction can be used to precisely study the spectra of light hypernuclei. Future experiments based on similar techniques, are expected to attain even better resolutions and rates.

  4. Beyond the Black Queen Hypothesis.

    PubMed

    Mas, Alix; Jamshidi, Shahrad; Lagadeuc, Yvan; Eveillard, Damien; Vandenkoornhuyse, Philippe

    2016-09-01

    The Black Queen Hypothesis, recently proposed to explain an evolution of dependency based on gene loss, is gaining ground. This paper focuses on how the evolution of dependency transforms interactions and the community. Using agent-based modeling we suggest that species specializing in the consumption of a common good escape competition and therefore favor coexistence. This evolutionary trajectory could open the way for novel long-lasting interactions and a need to revisit the classically accepted assembly rules. Such evolutionary events also reshape the structure and dynamics of communities, depending on the spatial heterogeneity of the common good production. Let Black be the new black! PMID:26953598

  5. ``Towards Strange Metallic Holography'

    SciTech Connect

    Hartnoll, Sean A.; Polchinski, Joseph; Silverstein, Eva; Tong, David; /Cambridge U., DAMTP /Santa Barbara, KITP /UC, Santa Barbara

    2010-08-26

    We initiate a holographic model building approach to 'strange metallic' phenomenology. Our model couples a neutral Lifshitz-invariant quantum critical theory, dual to a bulk gravitational background, to a finite density of gapped probe charge carriers, dually described by D-branes. In the physical regime of temperature much lower than the charge density and gap, we exhibit anomalous scalings of the temperature and frequency dependent conductivity. Choosing the dynamical critical exponent z appropriately we can match the non-Fermi liquid scalings, such as linear resistivity, observed in strange metal regimes. As part of our investigation we outline three distinct string theory realizations of Lifshitz geometries: from F theory, from polarized branes, and from a gravitating charged Fermi gas. We also identify general features of renormalization group flow in Lifshitz theories, such as the appearance of relevant charge-charge interactions when z {ge} 2. We outline a program to extend this model building approach to other anomalous observables of interest such as the Hall conductivity.

  6. Eddies off the Queen Charlotte Islands

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The bright red, green, and turquoise patches to the west of British Columbia's Queen Charlotte Islands and Alaska's Alexander Archipelago highlight the presence of biological activity in the ocean. These colors indicate high concentrations of chlorophyll, the primary pigment found in phytoplankton. Notice that there are a number of eddies visible in the Pacific Ocean in this pseudo-color scene. The eddies are formed by strong outflow currents from rivers along North America's west coast that are rich in nutrients from the springtime snowmelt running off the mountains. This nutrient-rich water helps stimulate the phytoplankton blooms within the eddies. (For more details, read Tracking Eddies that Feed the Sea.) To the west of the eddies in the water, another type of eddy-this one in the atmosphere-forms the clouds into the counterclockwise spiral characteristic of a low pressure system in the Northern Hemisphere. (Click on the image above to see it at full resolution; or click to see the scene in true-color.) The snow-covered mountains of British Columbia are visible in the upper righthand corner of the image. This scene was constructed using SeaWiFS data collected on June 13, 2002. SeaWiFS image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  7. Converting neutron stars into strange stars

    NASA Technical Reports Server (NTRS)

    Olinto, A. V.

    1991-01-01

    If strange matter is formed in the interior of a neutron star, it will convert the entire neutron star into a strange star. The proposed mechanisms are reviewed for strange matter seeding and the possible strange matter contamination of neutron star progenitors. The conversion process that follows seeding and the recent calculations of the conversion timescale are discussed.

  8. Electrically charged strange quark stars

    SciTech Connect

    Negreiros, Rodrigo Picanco; Weber, Fridolin; Malheiro, Manuel; Usov, Vladimir

    2009-10-15

    The possible existence of compact stars made of absolutely stable strange quark matter--referred to as strange stars--was pointed out by Witten almost a quarter of a century ago. One of the most amazing features of such objects concerns the possible existence of ultrastrong electric fields on their surfaces, which, for ordinary strange matter, is around 10{sup 18} V/cm. If strange matter forms a color superconductor, as expected for such matter, the strength of the electric field may increase to values that exceed 10{sup 19} V/cm. The energy density associated with such huge electric fields is on the same order of magnitude as the energy density of strange matter itself, which, as shown in this paper, alters the masses and radii of strange quark stars at the 15% and 5% levels, respectively. Such mass increases facilitate the interpretation of massive compact stars, with masses of around 2M{sub {center_dot}}, as strange quark stars.

  9. Magnetic Field of Strange Dwarfs

    NASA Astrophysics Data System (ADS)

    Baghdasaryan, D. S.

    2016-03-01

    The generation of a magnetic field in a strange quark star owing to differential rotation of the superfluid and superconducting quark core relative to the normal electron-nuclear crust of the star is examined. The maximum possible magnetic field on the surface is estimated for various models of strange dwarfs. Depending on the configuration parameters, i.e., the mass M and radius R of the star, a range of 103-105 G is found. These values of the magnetic field may be an additional condition for identification of strange dwarfs among the extensive class of observed white dwarfs.

  10. Strangeness in Nucleon

    SciTech Connect

    Benaoum, Hachemi

    2008-04-01

    Results of the parity violating asymmetry APV for longitudinally polarized 3 GeV electrons from both hydrogen and helium cryogenic targets, at small scatteting angle thetalab~6 ° are presented. The asymmetry for hydrogen is a function of a linear combination of GEs and GMs, the strange quark contributions to the electric and magnetic form factors of the nucleon respectively, and that for 4He is a function solely of GEs. The combination of the two results therefore allows GEs and GMs to be separately determined.

  11. Strange perspectives at FAIR

    NASA Astrophysics Data System (ADS)

    Steinheimer, J.; Sturm, C.; Schramm, S.; Stöcker, H.

    2010-09-01

    Adjacent to the existing accelerator complex of the GSI Helmholtz Centre for Heavy Ion Research at Darmstadt, Germany, the Facility for Antiproton and Ion Research (FAIR) substantially expands research goals and technical possibilities. It will provide worldwide unique accelerator and experimental facilities allowing for a large variety of unprecedented fore-front research in hadron, nuclear and atomic physics as well as applied sciences which will be described briefly in this paper. The start version of FAIR, the so-called Modularized Start Version, will deliver first beams in 2017/2018. As an example the paper presents research efforts on strangeness at FAIR using heavy ion collisions, exotic nuclei from fragmentation and antiprotons to tackle various topics in this area. In particular hypernuclei and metastable exotic multi-hypernuclear objects will be investigated.

  12. Strangeness and onset of deconfinement

    SciTech Connect

    Becattini, F.

    2012-05-15

    I will review the current status of global strangeness production in relativistic heavy-ion collisions with particular emphasis on recent results from core-corona model. I will discuss its relevance for the detection of the onset of deconfinement.

  13. Torsional oscillations of strange stars

    NASA Astrophysics Data System (ADS)

    Mannarelli, Massimo

    2014-11-01

    Strange stars are one of the hypothetical compact stellar objects that can be formed after a supernova explosion. The existence of these objects relies on the absolute stability of strange collapsed quark matter with respect to standard nuclear matter. We discuss simple models of strange stars with a bare quark matter surface, thus standard nuclear matter is completely absent. In these models an electric dipole layer a few hundreds Fermi thick should exist close to the star surface. Studying the torsional oscillations of the electrically charged layer we estimate the emitted power, finding that it is of the order of 1045 erg/s, meaning that these objects would be among the brightest compact sources in the heavens. The associated relaxation times are very uncertain, with values ranging between microseconds and minutes, depending on the crust thickness. Although part of the radiated power should be absorbed by the electrosphere surrounding the strange star, a sizable fraction of photons should escape and be detectable.

  14. How Strange is the Proton?

    SciTech Connect

    Piotr Decowski

    2006-11-15

    The paper discusses application of parity violating polarized electron scattering off nucleons to study strange form factors of the nucleon. The results from the recent HAPPEX experiment are discussed in more detail.

  15. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing Caribbean queen conch intact. 622... ATLANTIC Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands § 622.493 Landing Caribbean queen conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat...

  16. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing Caribbean queen conch intact. 622... ATLANTIC Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands § 622.493 Landing Caribbean queen conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat...

  17. Strange Star Surface: A Crust with Nuggets

    SciTech Connect

    Jaikumar, Prashanth; Reddy, Sanjay; Steiner, Andrew W.

    2006-02-03

    We reexamine the surface composition of strange stars. Strange quark stars are hypothetical compact stars which could exist if strange quark matter was absolutely stable. It is widely accepted that they are characterized by an enormous density gradient (10{sup 26} g/cm{sup 4}) and large electric fields at the surface. By investigating the possibility of realizing a heterogeneous crust, comprised of nuggets of strange quark matter embedded in an uniform electron background, we find that the strange star surface has a much reduced density gradient and negligible electric field. We comment on how our findings will impact various proposed observable signatures for strange stars.

  18. Honey Bee (Apis mellifera) Queen Reproductive Potential Affects Queen Mandibular Gland Pheromone Composition and Worker Retinue Response.

    PubMed

    Rangel, Juliana; Böröczky, Katalin; Schal, Coby; Tarpy, David R

    2016-01-01

    Reproductive division of labor is one of the defining traits of honey bees (Apis mellifera), with non-reproductive tasks being performed by workers while a single queen normally monopolizes reproduction. The decentralized organization of a honey bee colony is maintained in large part by a bouquet of queen-produced pheromones, the distribution of which is facilitated by contact among workers throughout the hive. Previous studies have shown that the developmental fate of honey bee queens is highly plastic, with queens raised from younger worker larvae exhibiting higher measures of reproductive potential compared to queens raised from older worker larvae. We investigated differences in the chemical composition of the mandibular glands and attractiveness to workers of "high-quality" queens (i.e., raised from first instar worker larvae; more queen-like) and "low-quality" queens (i.e., raised from third instar worker larvae; more worker-like). We characterized the chemical profiles of the mandibular glands of high-quality queens and low-quality queens using GC-MS and used the worker retinue response as a measure of the attractiveness to workers of high-quality queens vs. low-quality queens. We found that queen quality affected the chemical profiles of mandibular gland contents differently across years, showing significant differences in the production of the queen mandibular pheromone ("QMP") components HVA and 9-HDA in 2010, but no significant differences of any glandular compound in 2012. We also found that workers were significantly more attracted to high-quality queens than to low-quality queens in 2012, possibly because of increased attractiveness of their mandibular gland chemical profiles. Our results indicate that the age at which honey bee larvae enter the "queen-specific" developmental pathway influences the chemical composition of queen mandibular glands and worker behavior. However, these changes are not consistent across years, suggesting that other external

  19. Honey Bee (Apis mellifera) Queen Reproductive Potential Affects Queen Mandibular Gland Pheromone Composition and Worker Retinue Response

    PubMed Central

    Böröczky, Katalin; Schal, Coby; Tarpy, David R.

    2016-01-01

    Reproductive division of labor is one of the defining traits of honey bees (Apis mellifera), with non-reproductive tasks being performed by workers while a single queen normally monopolizes reproduction. The decentralized organization of a honey bee colony is maintained in large part by a bouquet of queen-produced pheromones, the distribution of which is facilitated by contact among workers throughout the hive. Previous studies have shown that the developmental fate of honey bee queens is highly plastic, with queens raised from younger worker larvae exhibiting higher measures of reproductive potential compared to queens raised from older worker larvae. We investigated differences in the chemical composition of the mandibular glands and attractiveness to workers of “high-quality” queens (i.e., raised from first instar worker larvae; more queen-like) and “low-quality” queens (i.e., raised from third instar worker larvae; more worker-like). We characterized the chemical profiles of the mandibular glands of high-quality queens and low-quality queens using GC-MS and used the worker retinue response as a measure of the attractiveness to workers of high-quality queens vs. low-quality queens. We found that queen quality affected the chemical profiles of mandibular gland contents differently across years, showing significant differences in the production of the queen mandibular pheromone (“QMP”) components HVA and 9-HDA in 2010, but no significant differences of any glandular compound in 2012. We also found that workers were significantly more attracted to high-quality queens than to low-quality queens in 2012, possibly because of increased attractiveness of their mandibular gland chemical profiles. Our results indicate that the age at which honey bee larvae enter the “queen-specific” developmental pathway influences the chemical composition of queen mandibular glands and worker behavior. However, these changes are not consistent across years, suggesting

  20. Strange Baryon Physics in Full Lattice QCD

    SciTech Connect

    Huey-Wen Lin

    2007-11-01

    Strange baryon spectra and form factors are key probes to study excited nuclear matter. The use of lattice QCD allows us to test the strength of the Standard Model by calculating strange baryon quantities from first principles.

  1. Strange Erosional Features

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 19 December 2003

    The strange erosional pattern seen in this THEMIS visible image differs greatly from the surrounding terrain of Lycus Sulchi (see context image). The crescent-shaped erosional pits trend in the southwest-northeast direction, indicating a dominant wind direction from the southwest. Why these pits eroded in the shapes that they did, however, is a mystery.

    Image information: VIS instrument. Latitude 18.6, Longitude 214.6 East (145.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Similarity of Body Size in Queens of the Wood ant Formica aquilonia from Optimal and Sub-Optimal Habitats Indicates a Strong Heritable Component

    PubMed Central

    Haatanen, Marja-Katariina; Sorvari, Jouni

    2013-01-01

    Body size in animals is affected by both genes and the environment (e.g., the amount of food resources). In ants, body size is related to several traits in an individual's physiology and life history. For example, a large queen may increase offspring production, thus increasing her overall fitness. In this study, whether sub-optimal environmental conditions affect the body size of queens of the red wood ant, Formica aquilonia Yarrow (Hymenoptera: Formicidae). The sizes (head width in mm) of virgin queens, i.e., gynes, originating from forest interiors (resource rich) and from commercial forest clear-cuts (resource poor) were measured. No differences in the body size of the queens from the two habitats were found. In addition, the within-nest variation in queen size was similar between habitat types. The results indicate that the body size variation of F. aquilonia queens is not sensitive to environmental variation, unlike F. aquilonia workers. The lack of environmental variation in queen size in F. aquilonia may be due to a strong selection in the past to monomorphic size in this obligately polygynous (multi-queened) species. PMID:24735372

  3. Production of strange particles in hadronization processes

    SciTech Connect

    Hofmann, W.

    1987-08-01

    Strange particles provide an important tool for the study of the color confinement mechanisms involved in hadronization processes. We review data on inclusive strange-particle production and on correlations between strange particles in high-energy reactions, and discuss phenomenological models for parton fragmentation. 58 refs., 24 figs.

  4. Strange-quark-matter stars

    SciTech Connect

    Glendenning, N.K.

    1989-11-01

    We investigate the implications of rapid rotation corresponding to the frequency of the new pulsar reported in the supernovae remnant SN1987A. It places very stringent conditions on the equation of state if the star is assumed to be bound by gravity alone. We find that the central energy density of the star must be greater than 13 times that of nuclear density to be stable against the most optimistic estimate of general relativistic instabilities. This is too high for the matter to consist of individual hadrons. We conclude that it is implausible that the newly discovered pulsar, if its half-millisecond signals are attributable to rotation, is a neutron star. We show that it can be a strange quark star, and that the entire family of strange stars can sustain high rotation if strange matter is stable at an energy density exceeding about 5.4 times that of nuclear matter. We discuss the conversion of a neutron star to strange star, the possible existence of a crust of heavy ions held in suspension by centrifugal and electric forces, the cooling and other features. 34 refs., 10 figs., 1 tab.

  5. How strange is pion electroproduction?

    NASA Astrophysics Data System (ADS)

    Gorchtein, Mikhail; Spiesberger, Hubert; Zhang, Xilin

    2016-01-01

    We consider pion production in parity-violating electron scattering (PVES) in the presence of nucleon strangeness in the framework of partial wave analysis with unitarity. Using the experimental bounds on the strange form factors obtained in elastic PVES, we study the sensitivity of the parity-violating asymmetry to strange nucleon form factors. For forward kinematics and electron energies above 1 GeV, we observe that this sensitivity may reach about 20% in the threshold region. With parity-violating asymmetries being as large as tens p.p.m., this study suggests that threshold pion production in PVES can be used as a promising way to better constrain strangeness contributions. Using this model for the neutral current pion production, we update the estimate for the dispersive γZ-box correction to the weak charge of the proton. In the kinematics of the Qweak experiment, our new prediction reads Re □γZV (E = 1.165 GeV) = (5.58 ± 1.41) ×10-3, an improvement over the previous uncertainty estimate of ± 2.0 ×10-3. Our new prediction in the kinematics of the upcoming MESA/P2 experiment reads Re □γZV (E = 0.155 GeV) = (1.1 ± 0.2) ×10-3.

  6. A strange cat in Dublin

    NASA Astrophysics Data System (ADS)

    O'Raifeartaigh, Cormac

    2012-11-01

    Not many life stories in physics involve Nazis, illicit sex, a strange cat and the genetic code. Thus, a new biography of the great Austrian physicist Erwin Schrödinger is always of interest, and with Erwin Schrödinger and the Quantum Revolution, veteran science writer John Gribbin does not disappoint.

  7. Effects of Insemination Quantity on Honey Bee Queen Physiology

    PubMed Central

    Richard, Freddie-Jeanne; Tarpy, David R.; Grozinger, Christina M.

    2007-01-01

    Mating has profound effects on the physiology and behavior of female insects, and in honey bee (Apis mellifera) queens, these changes are permanent. Queens mate with multiple males during a brief period in their early adult lives, and shortly thereafter they initiate egg-laying. Furthermore, the pheromone profiles of mated queens differ from those of virgins, and these pheromones regulate many different aspects of worker behavior and colony organization. While it is clear that mating causes dramatic changes in queens, it is unclear if mating number has more subtle effects on queen physiology or queen-worker interactions; indeed, the effect of multiple matings on female insect physiology has not been broadly addressed. Because it is not possible to control the natural mating behavior of queens, we used instrumental insemination and compared queens inseminated with semen from either a single drone (single-drone inseminated, or SDI) or 10 drones (multi-drone inseminated, or MDI). We used observation hives to monitor attraction of workers to SDI or MDI queens in colonies, and cage studies to monitor the attraction of workers to virgin, SDI, and MDI queen mandibular gland extracts (the main source of queen pheromone). The chemical profiles of the mandibular glands of virgin, SDI, and MDI queens were characterized using GC-MS. Finally, we measured brain expression levels in SDI and MDI queens of a gene associated with phototaxis in worker honey bees (Amfor). Here, we demonstrate for the first time that insemination quantity significantly affects mandibular gland chemical profiles, queen-worker interactions, and brain gene expression. Further research will be necessary to elucidate the mechanistic bases for these effects: insemination volume, sperm and seminal protein quantity, and genetic diversity of the sperm may all be important factors contributing to this profound change in honey bee queen physiology, queen behavior, and social interactions in the colony. PMID

  8. Effects of insemination quantity on honey bee queen physiology.

    PubMed

    Richard, Freddie-Jeanne; Tarpy, David R; Grozinger, Christina M

    2007-01-01

    Mating has profound effects on the physiology and behavior of female insects, and in honey bee (Apis mellifera) queens, these changes are permanent. Queens mate with multiple males during a brief period in their early adult lives, and shortly thereafter they initiate egg-laying. Furthermore, the pheromone profiles of mated queens differ from those of virgins, and these pheromones regulate many different aspects of worker behavior and colony organization. While it is clear that mating causes dramatic changes in queens, it is unclear if mating number has more subtle effects on queen physiology or queen-worker interactions; indeed, the effect of multiple matings on female insect physiology has not been broadly addressed. Because it is not possible to control the natural mating behavior of queens, we used instrumental insemination and compared queens inseminated with semen from either a single drone (single-drone inseminated, or SDI) or 10 drones (multi-drone inseminated, or MDI). We used observation hives to monitor attraction of workers to SDI or MDI queens in colonies, and cage studies to monitor the attraction of workers to virgin, SDI, and MDI queen mandibular gland extracts (the main source of queen pheromone). The chemical profiles of the mandibular glands of virgin, SDI, and MDI queens were characterized using GC-MS. Finally, we measured brain expression levels in SDI and MDI queens of a gene associated with phototaxis in worker honey bees (Amfor). Here, we demonstrate for the first time that insemination quantity significantly affects mandibular gland chemical profiles, queen-worker interactions, and brain gene expression. Further research will be necessary to elucidate the mechanistic bases for these effects: insemination volume, sperm and seminal protein quantity, and genetic diversity of the sperm may all be important factors contributing to this profound change in honey bee queen physiology, queen behavior, and social interactions in the colony. PMID

  9. Behavioral plasticity in ant queens: environmental manipulation induces aggression among normally peaceful queens in the socially polymorphic ant Leptothorax acervorum.

    PubMed

    Trettin, Jürgen; Seyferth, Thomas; Heinze, Jürgen

    2014-01-01

    The behavioral traits that shape the structure of animal societies vary considerably among species but appear to be less flexible within species or at least within populations. Populations of the ant Leptothorax acervorum differ in how queens interact with other queens. Nestmate queens from extended, homogeneous habitats tolerate each other and contribute quite equally to the offspring of the colony (polygyny: low reproductive skew). In contrast, nestmate queens from patchy habitats establish social hierarchies by biting and antennal boxing, and eventually only the top-ranking queen of the colony lays eggs (functional monogyny: high reproductive skew). Here we investigate whether queen-queen behavior is fixed within populations or whether aggression and high skew can be elicited by manipulation of socio-environmental factors in colonies from low skew populations. An increase of queen/worker ratio and to a lesser extent food limitation elicited queen-queen antagonism in polygynous colonies from Nürnberger Reichswald similar to that underlying social and reproductive hierarchies in high-skew populations from Spain, Japan, and Alaska. In manipulated colonies, queens differed more in ovarian status than in control colonies. This indicates that queens are in principle capable of adapting the magnitude of reproductive skew to environmental changes in behavioral rather than evolutionary time. PMID:24743352

  10. Photoresists for microlithography, or The Red Queen's Race

    NASA Astrophysics Data System (ADS)

    Dammel, Ralph R.

    2002-07-01

    Photolithography is a key component of the industry's ability to continue to shrink devices according to Moore's Law, and any improvements immediately translate into large economic benefits for the industry. The relative contribution of the wetware, i.e., the photoresists and other chemicals used in the photolithography step, vs. the contribution of the exposure tool development is investigated by expressing the resist performance improvement as a numerical aperture (NA). Using this equivalent NA concept, it is shown that the contribution from resist improvements has historically outpaced that from stepper NA improvements. However, R&D expenditures for hardware and wetware have consistently been at greatly different levels. While part of that difference is probably intrinsic in the cost structure of the respective development efforts, it is suggested that the relative amount of spending on resist R&D has historically not been at a level that optimizes the overall return for the industry.

  11. The maintenance of sex: Ronald Fisher meets the Red Queen

    PubMed Central

    2013-01-01

    Background Sex in higher diploids carries a two-fold cost of males that should reduce its fitness relative to cloning, and result in its extinction. Instead, sex is widespread and clonal species face early obsolescence. One possible reason is that sex is an adaptation that allows organisms to respond more effectively to endless changes in their environment. The purpose of this study was to model mutation and selection in a diploid organism in an evolving environment and ascertain their support for sex. Results We used a computational approach to model finite populations where a haploid environment subjects a diploid host to endlessly evolving change. Evolution in both populations is primarily through adoption of novel advantageous mutations within a large allele space. Sex outcompetes cloning by two complementary mechanisms. First, sexual diploids adopt advantageous homozygous mutations more rapidly than clonal ones under conditions of lag load (the gap between the actual adaptation of the diploid population and its theoretical optimum). This rate advantage can offset the higher fecundity of cloning. Second, a relative advantage to sex emerges where populations are significantly polymorphic, because clonal polymorphism runs the risk of clonal interference caused by selection on numerous lines of similar adaptation. This interference extends allele lifetime and reduces the rate of adaptation. Sex abolishes the interference, making selection faster and elevating population fitness. Differences in adaptation between sexual and clonal populations increase markedly with the number of loci under selection, the rate of mutation in the host, and a rapidly evolving environment. Clonal interference in these circumstances leads to conditions where the greater fecundity of clones is unable to offset their poor adaptation. Sexual and clonal populations then either co-exist, or sex emerges as the more stable evolutionary strategy. Conclusions Sex can out-compete clones in a rapidly evolving environment, such as that characterized by pathogens, where clonal interference reduces the adaptation of clonal populations and clones adopt advantageous mutations more slowly. Since all organisms carry parasitic loads, the model is of potentially general applicability. PMID:23962342

  12. Women in History--Queen Liliuokalani

    ERIC Educational Resources Information Center

    Koeppe, Tina

    2007-01-01

    This article profiles Queen Liliuokalani, Hawaii's last monarch. Liliuokalani was born in Hawaii in 1838 into the family of a high chief. She attended the Royal School, run by American missionaries, and received a high quality education and learned to love music, writing and politics. Liliuokalani was given the Christian name "Lydia" as a child.…

  13. Queen Margaret University College's Sustainable, Community Campus

    ERIC Educational Resources Information Center

    Woodman, Susan

    2006-01-01

    The new campus of Queen Margaret University College in the United Kingdom is designed to be a sustainable educational and community resource. Early consultation with students and staff on the campus design revealed a strong desire for a sustainable environment, with plenty of green space for all to enjoy. In response to this, the design focuses on…

  14. Surface lipids of queen-laid eggs do not regulate queen production in a fission-performing ant

    NASA Astrophysics Data System (ADS)

    Ruel, Camille; Lenoir, Alain; Cerdá, Xim; Boulay, Raphaël

    2013-01-01

    In animal societies, most collective and individual decision making depends on the presence of reproductive individuals. The efficient transmission of information among reproductive and non-reproductive individuals is therefore a determinant of colony organization. In social insects, the presence of a queen modulates multiple colonial activities. In many species, it negatively affects worker reproduction and the development of diploid larvae into future queens. The queen mostly signals her presence through pheromone emission, but the means by which these chemicals are distributed in the colony are still unclear. In several ant species, queen-laid eggs are the vehicle of the queen signal. The aim of this study was to investigate whether queen-laid eggs of the ant Aphaenogaster senilis possess queen-specific cuticular hydrocarbons and/or Dufour or poison gland compounds, and whether the presence of eggs inhibited larval development into queens. Our results show that the queen- and worker-laid eggs shared cuticular and Dufour hydrocarbons with the adults; however, their poison gland compounds were not similar. Queen-laid eggs had more dimethylalkanes and possessed a queen-specific mixture of cuticular hydrocarbons composed of 3,11 + 3,9 + 3,7-dimethylnonacosane, in higher proportions than did worker-laid eggs. Even though the queen-laid eggs were biochemically similar to the queen, their addition to experimentally queenless groups did not prevent the development of new queens. More studies are needed on the means by which queen ant pheromones are transmitted in the colony, and how these mechanisms correlates with life history traits.

  15. Surface lipids of queen-laid eggs do not regulate queen production in a fission-performing ant.

    PubMed

    Ruel, Camille; Lenoir, Alain; Cerdá, Xim; Boulay, Raphaël

    2013-01-01

    In animal societies, most collective and individual decision making depends on the presence of reproductive individuals. The efficient transmission of information among reproductive and non-reproductive individuals is therefore a determinant of colony organization. In social insects, the presence of a queen modulates multiple colonial activities. In many species, it negatively affects worker reproduction and the development of diploid larvae into future queens. The queen mostly signals her presence through pheromone emission, but the means by which these chemicals are distributed in the colony are still unclear. In several ant species, queen-laid eggs are the vehicle of the queen signal. The aim of this study was to investigate whether queen-laid eggs of the ant Aphaenogaster senilis possess queen-specific cuticular hydrocarbons and/or Dufour or poison gland compounds, and whether the presence of eggs inhibited larval development into queens. Our results show that the queen- and worker-laid eggs shared cuticular and Dufour hydrocarbons with the adults; however, their poison gland compounds were not similar. Queen-laid eggs had more dimethylalkanes and possessed a queen-specific mixture of cuticular hydrocarbons composed of 3,11 + 3,9 + 3,7-dimethylnonacosane, in higher proportions than did worker-laid eggs. Even though the queen-laid eggs were biochemically similar to the queen, their addition to experimentally queenless groups did not prevent the development of new queens. More studies are needed on the means by which queen ant pheromones are transmitted in the colony, and how these mechanisms correlates with life history traits. PMID:23224071

  16. Assessing the mating 'health' of commercial honey bee queens.

    PubMed

    Tarpy, David R; Keller, Jennifer J; Caren, Joel R; Delaney, Deborah A

    2012-02-01

    Honey bee queens mate with multiple males, which increases the total genetic diversity within colonies and has been shown to confer numerous benefits for colony health and productivity. Recent surveys of beekeepers have suggested that 'poor queens' are a top management concern, thus investigating the reproductive quality and mating success of commercially produced honey bee queens is warranted. We purchased 80 commercially produced queens from large queen breeders in California and measured them for their physical size (fresh weigh and thorax width), insemination success (stored sperm counts and sperm viability), and mating number (determined by patriline genotyping of worker offspring). We found that queens had an average of 4.37 +/- 1.446 million stored sperm in their spermathecae with an average viability of 83.7 +/- 13.33%. We also found that the tested queens had mated with a high number of drones (average effective paternity frequency: 17.0 +/- 8.98). Queen "quality" significantly varied among commercial sources for physical characters but not for mating characters. These findings suggest that it may be more effective to improve overall queen reproductive potential by culling lower-quality queens rather than systematically altering current queen production practices. PMID:22420250

  17. Queen pheromone regulates egg production in a termite.

    PubMed

    Yamamoto, Yuuka; Matsuura, Kenji

    2011-10-23

    In social insects, resource allocation is a key factor that influences colony survival and growth. Optimal allocation to queens and brood is essential for maximum colony productivity, requiring colony members to have information on the total reproductive power in colonies. However, the mechanisms regulating egg production relative to the current labour force for brood care remain poorly known. Recently, a volatile chemical was identified as a termite queen pheromone that inhibits the differentiation of new neotenic reproductives (secondary reproductives developed from nymphs or workers) in Reticulitermes speratus. The same volatile chemical is also emitted by eggs. This queen pheromone would therefore be expected to act as an honest message of the reproductive power about queens. In this study, we examined how the queen pheromone influences the reproductive rate of queens in R. speratus. We compared the number of eggs produced by each queen between groups with and without exposure to artificial queen pheromone. Exposure to the pheromone resulted in a significant decrease in egg production in both single-queen and multiple-queen groups. This is the first report supporting the role of queen pheromones as a signal regulating colony-level egg production, using synthetically derived compounds in a termite. PMID:21543395

  18. Neutron stars and strange matter

    SciTech Connect

    Cooperstein, J.

    1986-01-01

    The likelihood is investigated that quark matter with strangeness of order unity resides in neutron stars. In the strong coupling regime near rho/sub 0/ this is found to be unlikely. Considering higher densities where perturbative expansions are used, we find a lower bound to be at 7rho/sub 0/ for the transition density. This is higher than the inferred density of observed neutron stars, and thus the transition to quark matter is precluded. 15 refs., 3 figs.

  19. Open strangeness production in CLAS

    SciTech Connect

    G. Niculescu

    2003-05-01

    An extensive program dedicated to the study of open strangeness systems was established in Hall B at Jefferson Lab. This program takes full advantage of the excellent characteristics of the CEBAF accelerator combined with the almost complete angular coverage of the CLAS detector. A general overview of the program is given, as well as results for the angular dependence of the electroproduction of kaon-hyperon final states.

  20. Sperm use economy of honeybee (Apis mellifera) queens.

    PubMed

    Baer, Boris; Collins, Jason; Maalaps, Kristiina; den Boer, Susanne P A

    2016-05-01

    The queens of eusocial ants, bees, and wasps only mate during a very brief period early in life to acquire and store a lifetime supply of sperm. As sperm cannot be replenished, queens have to be highly economic when using stored sperm to fertilize eggs, especially in species with large and long-lived colonies. However, queen fertility has not been studied in detail, so that we have little understanding of how economic sperm use is in different species, and whether queens are able to influence their sperm use. This is surprising given that sperm use is a key factor of eusocial life, as it determines the fecundity and longevity of queens and therefore colony fitness. We quantified the number of sperm that honeybee (Apis mellifera) queens use to fertilize eggs. We examined sperm use in naturally mated queens of different ages and in queens artificially inseminated with different volumes of semen. We found that queens are remarkably efficient and only use a median of 2 sperm per egg fertilization, with decreasing sperm use in older queens. The number of sperm in storage was always a significant predictor for the number of sperm used per fertilization, indicating that queens use a constant ratio of spermathecal fluid relative to total spermathecal volume of 2.364 × 10(-6) to fertilize eggs. This allowed us to calculate a lifetime fecundity for honeybee queens of around 1,500,000 fertilized eggs. Our data provide the first empirical evidence that honeybee queens do not manipulate sperm use, and fertilization failures in worker-destined eggs are therefore honest signals that workers can use to time queen replacement, which is crucial for colony performance and fitness. PMID:27217944

  1. Prospects for strangeness measurement in ALICE

    SciTech Connect

    Vernet, R.

    2008-09-15

    The study of strangeness production at LHC will bring significant information on the bulk chemical properties, its dynamics, and the hadronization mechanisms involved at these energies. The ALICE experiment will measure strange particles from topology (secondary vertices) and from resonance decays over a wide range in transverse momentum and shed light on this new QCD regime. These motivations will be presented as well as the identification performance of ALICE for strange hadrons.

  2. Is the sub-millisecond pulsar strange?

    NASA Technical Reports Server (NTRS)

    Frieman, Joshua A.; Olinto, Angela V.

    1989-01-01

    The possibility that the submillisecond pulsar from supernova 1987A is composed of strange matter is theoretically discussed. It is shown that for a range of hadron parameters, the maximum rotation rate of secularly stable strange stars may exceed that of the half-millisecond pulsar and the nonrotating maximum mass is greater than 1.52 solar mass. The low-mass companion(s) to SN1987A, inferred from the periodic modulations of the optical signal, can be accounted for by stable strange-matter lump(s) ejected from the young strange star.

  3. Colony strength and queen replacement in Melipona marginata (Apidae: Meliponini).

    PubMed

    Kleinert, A de M P

    2005-08-01

    Physogastric queens of Melipona marginata were removed from their colonies in order to verify the acceptance of a new queen by workers. Colony strength was evaluated according to queen oviposition rate and comb diameters. Replacement was observed seven times. Its occurrence and speed related positively to colony strength, independently of queen's age. In weak colonies, queen replacement was observed only once, following colony population increase that occurred after introduction of combs from another colony. Worker oviposition after queen removal was observed three times: in a strong colony with virgin queens and males, and in two of the weak colonies. In the first two or three days of new queen oviposition, during which most of the eggs were eaten by the queen, worker oviposition preceded almost all provisioning and oviposition processes (POPs). After this period, worker oviposition decreased until it reached around 25% of the POPs. Daily oviposition rate of young queens decreased or was even interrupted by hatching of their first brood. PMID:16341425

  4. Additional Strange Hadrons from QCD Thermodynamics and Strangeness Freezeout in Heavy Ion Collisions

    NASA Astrophysics Data System (ADS)

    Bazavov, A.; Ding, H.-T.; Hegde, P.; Kaczmarek, O.; Karsch, F.; Laermann, E.; Maezawa, Y.; Mukherjee, Swagato; Ohno, H.; Petreczky, P.; Schmidt, C.; Sharma, S.; Soeldner, W.; Wagner, M.

    2014-08-01

    We compare lattice QCD results for appropriate combinations of net strangeness fluctuations and their correlations with net baryon number fluctuations with predictions from two hadron resonance gas (HRG) models having different strange hadron content. The conventionally used HRG model based on experimentally established strange hadrons fails to describe the lattice QCD results in the hadronic phase close to the QCD crossover. Supplementing the conventional HRG with additional, experimentally uncharted strange hadrons predicted by quark model calculations and observed in lattice QCD spectrum calculations leads to good descriptions of strange hadron thermodynamics below the QCD crossover. We show that the thermodynamic presence of these additional states gets imprinted in the yields of the ground-state strange hadrons leading to a systematic 5-8 MeV decrease of the chemical freeze-out temperatures of ground-state strange baryons.

  5. Maximum rotation frequency of strange stars

    SciTech Connect

    Zdunik, J.L.; Haensel, P. )

    1990-07-15

    Using the MIT bag model of strange-quark matter, we calculate the maximum angular frequency of the uniform rotation of strange stars. After studying a broad range of the MIT bag-model parameters, we obtain an upper bound of 12.3 kHz.

  6. Strangeness production with protons and pions

    SciTech Connect

    Dover, C.B.

    1993-04-01

    We discuss the spectrum of physics questions related to strangeness which could be addressed with intense beams of protons and pions in the few GeV region. We focus on various aspects of strangeness production, including hyperon production in pp collisions, studies of hyperon-nucleon scattering, production of hypernuclei in proton and pion-nucleus collisions, and spin phenomena in hypernuclei.

  7. Strangeness production with protons and pions

    SciTech Connect

    Dover, C.B.

    1993-01-01

    We discuss the spectrum of physics questions related to strangeness which could be addressed with intense beams of protons and pions in the few GeV region. We focus on various aspects of strangeness production, including hyperon production in pp collisions, studies of hyperon-nucleon scattering, production of hypernuclei in proton and pion-nucleus collisions, and spin phenomena in hypernuclei.

  8. Strangeness detection in ALICE experiment at LHC

    SciTech Connect

    Safarik, K.

    1995-07-15

    The authors present some parameters of the ALICE detector which concern the detection of strange particles. The results of a simulation for neutral strange particles and cascades, together with estimated rates are presented. They also briefly discuss the detection of charged K-mesons. Finally, they mention the possibility of open charm particle detection.

  9. QCD in Neutron Stars and Strange Stars

    SciTech Connect

    Weber, Fridolin; Negreiros, Rodrigo

    2011-05-24

    This paper provides an overview of the possible role of Quantum Chromo Dynamics (QCD) for neutron stars and strange stars. The fundamental degrees of freedom of QCD are quarks, which may exist as unconfined (color superconducting) particles in the cores of neutron stars. There is also the theoretical possibility that a significantly large number of up, down, and strange quarks may settle down in a new state of matter known as strange quark matter, which, by hypothesis, could be more stable than even the most stable atomic nucleus, {sup 56}Fe. In the latter case new classes of self-bound, color superconducting objects, ranging from strange quark nuggets to strange quark stars, should exist. The properties of such objects will be reviewed along with the possible existence of deconfined quarks in neutron stars. Implications for observational astrophysics are pointed out.

  10. The Maximum Mass of Rotating Strange Stars

    NASA Astrophysics Data System (ADS)

    Szkudlarek, M.; Gondek-Rosiń; ska, D.; Villain, L.; Ansorg, M.

    2012-12-01

    Strange quark stars are considered as a possible alternative to neutron stars as compact objects (e.g. Weber 2003). A hot compact star (a proto-neutron star or a strange star) born in a supernova explosion or a remnant of neutron stars binary merger are expected to rotate differentially and be important sources of gravitational waves. We present results of the first relativistic calculations of differentially rotating strange quark stars for broad ranges of degree of differential rotation and maximum densities. Using a highly accurate, relativistic code we show that rotation may cause a significant increase of maximum allowed mass of strange stars, much larger than in the case of neutron stars with the same degree of differential rotation. Depending on the maximum allowed mass a massive neutron star (strange star) can be temporarily stabilized by differential rotation or collapse to a black hole.

  11. Matricide and queen sex allocation in a yellowjacket wasp

    NASA Astrophysics Data System (ADS)

    Loope, Kevin J.

    2016-08-01

    In many colonies of social insects, the workers compete with each other and with the queen over the production of the colony's males. In some species of social bees and wasps with annual societies, this intra-colony conflict even results in matricide—the killing of the colony's irreplaceable queen by a daughter worker. In colonies with low effective paternity and high worker-worker relatedness, workers value worker-laid males more than queen-laid males, and thus may benefit from queen killing. Workers gain by eliminating the queen because she is a competing source of male eggs and actively inhibits worker reproduction through policing. However, matricide may be costly to workers if it reduces the production of valuable new queens and workers. Here, I test a theoretical prediction regarding the timing of matricide in a wasp, Dolichovespula arenaria, recently shown to have facultative matricide based on intra-colony relatedness. Using analyses of collected, mature colonies and a surgical manipulation preventing queens from laying female eggs, I show that workers do not preferentially kill queens who are only producing male eggs. Instead, workers sometimes kill queens laying valuable females, suggesting a high cost of matricide. Although matricide is common and typically occurs only in low-paternity colonies, it seems that workers sometimes pay substantial costs in this expression of conflict over male parentage.

  12. Matricide and queen sex allocation in a yellowjacket wasp.

    PubMed

    Loope, Kevin J

    2016-08-01

    In many colonies of social insects, the workers compete with each other and with the queen over the production of the colony's males. In some species of social bees and wasps with annual societies, this intra-colony conflict even results in matricide-the killing of the colony's irreplaceable queen by a daughter worker. In colonies with low effective paternity and high worker-worker relatedness, workers value worker-laid males more than queen-laid males, and thus may benefit from queen killing. Workers gain by eliminating the queen because she is a competing source of male eggs and actively inhibits worker reproduction through policing. However, matricide may be costly to workers if it reduces the production of valuable new queens and workers. Here, I test a theoretical prediction regarding the timing of matricide in a wasp, Dolichovespula arenaria, recently shown to have facultative matricide based on intra-colony relatedness. Using analyses of collected, mature colonies and a surgical manipulation preventing queens from laying female eggs, I show that workers do not preferentially kill queens who are only producing male eggs. Instead, workers sometimes kill queens laying valuable females, suggesting a high cost of matricide. Although matricide is common and typically occurs only in low-paternity colonies, it seems that workers sometimes pay substantial costs in this expression of conflict over male parentage. PMID:27350328

  13. The strange beauty of the proton

    NASA Astrophysics Data System (ADS)

    Bijker, Roelof; Ferretti, Jacopo; Santopinto, Elena

    2012-10-01

    The contribution of strange quarks to the proton is addressed in two different models of the nucleon, a phenomenological two-component model in which the nucleon is described in terms of an intrinsic three-quark structure surrounded by a meson cloud, and the unquenched quark model in which the effects of the sea quarks are taken into account through a 3P0 quark-antiquark pair creation mechanism. The results for the strange magnetic moment and the strangeness radius of the proton are found to be small, in agreement with the latest experimental results from parity-violating electron scattering and recent lattice calculations.

  14. Theoretical perspectives on strange physics

    NASA Astrophysics Data System (ADS)

    Ellis, J.

    1983-04-01

    Kaons are heavy enough to have an interesting range of decay modes available to them, and light enough to be produced in sufficient numbers to explore rate modes with satisfying statistics. Kaons and their decays have provided at least two major breakthroughs in fundamental physics: CP violation, and their lack of flavor-changing neutral interactions warned us to expect charm. In addition, K0-anti K0 mixing has provided one of the most elegant and sensitive laboratories for testing quantum mechanics. There is every reason to expect that future generations of kaon experiments with intense sources would add further to fundamental physics. This talk attempts to set future kaon experiments in a general theoretical context, and indicate how they bear upon fundamental theoretical issues. A survey of different experiments which would be done with an Intense Medium Energy Source of Strangeness, including rare K decays, probes of the nature of CP isolation, (SIGMA) decays, hyperon decays and neutrino physics is given.

  15. Strangeness production in PHENIX experiment

    NASA Astrophysics Data System (ADS)

    Kotov, D. O.

    2016-01-01

    The PHENIX experiment at RHIC has measured production of K±, Ks, K* and ϕmesons in p+p, d+Au, Cu+Cu and Au+Au collisions at √sNN = 62.4 and 200 GeV. While p+p collisions provide a baseline and are used for precision tests of pQCD calculations, for heavier colliding systems such as d+Au, Cu+Cu and Au+Au nuclear modification factors are studied at different centralities. These systematic studies enrich current understanding of the strange meson production and its difference from light quark hadrons. The role of radial flow and coalescence in particle production is discussed.

  16. Effects of mosquito control pesticides on competent queen conch (Strombus gigas) larvae.

    PubMed

    Delgado, Gabriel A; Glazer, Robert A; Wetzel, Dana

    2013-10-01

    Pesticides are applied seasonally in the Florida Keys to control nuisance populations of mosquitoes that pose a health threat to humans. There is, however, a need to investigate the effects of these pesticides on non-target marine organisms. We tested naled and permethrin, two mosquito adulticides used in the Keys, on a critical early life-history stage of queen conch (Strombus gigas). We conducted 12-h exposure experiments on competent (i.e., capable of undergoing metamorphosis) queen conch larvae using environmentally relevant pesticide concentrations. We found that there was little to no mortality and that the pesticides did not induce or interfere with metamorphosis. However, after introduction of a natural metamorphic cue (extract of the red alga Laurencia potei), a significantly greater proportion of larvae underwent metamorphosis in the pesticide treatments than in those with the alga alone. In addition to the morphogenetic pathway that induces metamorphosis when stimulated, there thus appears to be a regulatory pathway that enhances the response to metamorphic triggers, as suggested by the increased sensitivity of the queen conch larvae to the algal cue after pesticide exposure (i.e., the pesticides stimulated the regulatory pathway). The regulatory pathway probably plays a role in the identification of high-quality habitat for metamorphosis, as the increased response to the algal cue suggests. Aerial drift and runoff can carry these pesticides into nearshore waters, where they may act as a false signal of favorable conditions and facilitate metamorphosis in suboptimal habitat, thus adversely affecting recruitment in nearshore queen conch populations. PMID:24243960

  17. Alternative mating behaviors of the queen polymorphic ant Temnothorax longispinosus

    NASA Astrophysics Data System (ADS)

    Howard, Kenneth J.; Kennedy, David

    2007-11-01

    Mating behaviors of ants fall into two categories: female calling, in which a female alate releases pheromones that attract males, and male swarming, in which large male aggregations attract females. Female calling is common in species with queens that return to their natal nest to found colonies dependently after mating, while male swarming is common in species with queens that disperse to found independently. In some species that display both founding strategies, a queen-size polymorphism has evolved in which dependent-founding queens are smaller than independent-founding queens. Dependent founding is likely difficult if gynes (virgin queens) are mating in distant swarms. Therefore, a queen may adopt one or the other mating strategy based on its size and founding behavior. We investigated mating behaviors in the queen-polymorphic ant, Temnothorax longispinosus. Observations in laboratory mating arenas indicated that small gynes exhibited significantly lower flight activity than large gynes. Both forms mated in male swarms, and neither form exhibited female calling. The reduced flight activity of the small morph may facilitate returning to the natal nest after mating, provided the mating swarm is located nearby. Therefore, alternative colony-founding behaviors may be possible without the evolution of female-calling behavior; however, the reduced flight activity of small morphs may require that mating swarms are not distant from the natal nest.

  18. Alternative mating behaviors of the queen polymorphic ant Temnothorax longispinosus.

    PubMed

    Howard, Kenneth J; Kennedy, David

    2007-11-01

    Mating behaviors of ants fall into two categories: female calling, in which a female alate releases pheromones that attract males, and male swarming, in which large male aggregations attract females. Female calling is common in species with queens that return to their natal nest to found colonies dependently after mating, while male swarming is common in species with queens that disperse to found independently. In some species that display both founding strategies, a queen-size polymorphism has evolved in which dependent-founding queens are smaller than independent-founding queens. Dependent founding is likely difficult if gynes (virgin queens) are mating in distant swarms. Therefore, a queen may adopt one or the other mating strategy based on its size and founding behavior. We investigated mating behaviors in the queen-polymorphic ant, Temnothorax longispinosus. Observations in laboratory mating arenas indicated that small gynes exhibited significantly lower flight activity than large gynes. Both forms mated in male swarms, and neither form exhibited female calling. The reduced flight activity of the small morph may facilitate returning to the natal nest after mating, provided the mating swarm is located nearby. Therefore, alternative colony-founding behaviors may be possible without the evolution of female-calling behavior; however, the reduced flight activity of small morphs may require that mating swarms are not distant from the natal nest. PMID:17653686

  19. Intraspecific queen parasitism in a highly eusocial bee

    PubMed Central

    Wenseleers, Tom; Alves, Denise A.; Francoy, Tiago M.; Billen, Johan; Imperatriz-Fonseca, Vera L.

    2011-01-01

    Insect societies are well-known for their advanced cooperation, but their colonies are also vulnerable to reproductive parasitism. Here, we present a novel example of an intraspecific social parasitism in a highly eusocial bee, the stingless bee Melipona scutellaris. In particular, we provide genetic evidence which shows that, upon loss of the mother queen, many colonies are invaded by unrelated queens that fly in from unrelated hives nearby. The reasons for the occurrence of this surprising form of social parasitism may be linked to the fact that unlike honeybees, Melipona bees produce new queens in great excess of colony needs, and that this exerts much greater selection on queens to seek alternative reproductive options, such as by taking over other nests. Overall, our results are the first to demonstrate that queens in highly eusocial bees can found colonies not only via supersedure or swarming, but also by infiltrating and taking over other unrelated nests. PMID:20961883

  20. Strangeness suppression in the unquenched quark model

    NASA Astrophysics Data System (ADS)

    Bijker, Roelof; García-Tecocoatzi, Hugo; Santopinto, Elena

    2016-07-01

    In this contribution, we discuss the strangeness suppression in the proton in the framework of the unquenched quark model. The theoretical results are in good agreement with the values extracted from CERN and JLab experiments.

  1. Strange Creatures: An Additive Wood Sculpture Project.

    ERIC Educational Resources Information Center

    Wales, Andrew

    2002-01-01

    Describes an art project where students create strange creatures using scraps of wood. Discusses how the students use the wood and other materials. Explains that the students also write about the habitat characteristics of their creatures. Includes learning objectives. (CMK)

  2. Strange quark matter fragmentation in astrophysical events

    NASA Astrophysics Data System (ADS)

    Paulucci, L.; Horvath, J. E.

    2014-06-01

    The conjecture of Bodmer-Witten-Terazawa suggesting a form of quark matter (Strange Quark Matter) as the ground state of hadronic interactions has been studied in laboratory and astrophysical contexts by a large number of authors. If strange stars exist, some violent events involving these compact objects, such as mergers and even their formation process, might eject some strange matter into the interstellar medium that could be detected as a trace signal in the cosmic ray flux. To evaluate this possibility, it is necessary to understand how this matter in bulk would fragment in the form of strangelets (small lumps of strange quark matter in which finite effects become important). We calculate the mass distribution outcome using the statistical multifragmentation model and point out several caveats affecting it. In particular, the possibility that strangelets fragmentation will render a tiny fraction of contamination in the cosmic ray flux is discussed.

  3. Patterns of viral infection in honey bee queens.

    PubMed

    Francis, Roy Mathew; Nielsen, Steen Lykke; Kryger, Per

    2013-03-01

    The well-being of a colony and replenishment of the workers depends on a healthy queen. Diseases in queens are seldom reported, and our knowledge on viral infection in queens is limited. In this study, 86 honey bee queens were collected from beekeepers in Denmark. All queens were tested separately by two real-time PCRs: one for the presence of deformed wing virus (DWV), and one that would detect sequences of acute bee-paralysis virus, Kashmir bee virus and Israeli acute paralysis virus (AKI complex). Worker bees accompanying the queen were also analysed. The queens could be divided into three groups based on the level of infection in their head, thorax, ovary, intestines and spermatheca. Four queens exhibited egg-laying deficiency, but visually all queens appeared healthy. Viral infection was generally at a low level in terms of AKI copy numbers, with 134/430 tissues (31 %) showing the presence of viral infection ranging from 10(1) to 10(5) copies. For DWV, 361/340 tissues (84 %) showed presence of viral infection (DWV copies ranging from 10(2) to 10(12)), with 50 tissues showing viral titres >10(7) copies. For both AKI and DWV, the thorax was the most frequently infected tissue and the ovaries were the least frequently infected. Relative to total mass, the spermatheca showed significantly higher DWV titres than the other tissues. The ovaries had the lowest titre of DWV. No significant differences were found among tissues for AKI. A subsample of 14 queens yielded positive results for the presence of negative-sense RNA strands, thus demonstrating active virus replication in all tissues. PMID:23223622

  4. Patterns of viral infection in honey bee queens

    PubMed Central

    Francis, Roy Mathew; Nielsen, Steen Lykke

    2013-01-01

    The well-being of a colony and replenishment of the workers depends on a healthy queen. Diseases in queens are seldom reported, and our knowledge on viral infection in queens is limited. In this study, 86 honey bee queens were collected from beekeepers in Denmark. All queens were tested separately by two real-time PCRs: one for the presence of deformed wing virus (DWV), and one that would detect sequences of acute bee-paralysis virus, Kashmir bee virus and Israeli acute paralysis virus (AKI complex). Worker bees accompanying the queen were also analysed. The queens could be divided into three groups based on the level of infection in their head, thorax, ovary, intestines and spermatheca. Four queens exhibited egg-laying deficiency, but visually all queens appeared healthy. Viral infection was generally at a low level in terms of AKI copy numbers, with 134/430 tissues (31 %) showing the presence of viral infection ranging from 101 to 105 copies. For DWV, 361/340 tissues (84 %) showed presence of viral infection (DWV copies ranging from 102 to 1012), with 50 tissues showing viral titres >107 copies. For both AKI and DWV, the thorax was the most frequently infected tissue and the ovaries were the least frequently infected. Relative to total mass, the spermatheca showed significantly higher DWV titres than the other tissues. The ovaries had the lowest titre of DWV. No significant differences were found among tissues for AKI. A subsample of 14 queens yielded positive results for the presence of negative-sense RNA strands, thus demonstrating active virus replication in all tissues. PMID:23223622

  5. Strange Attractors in Drift Wave Turbulence

    SciTech Connect

    J.L.V. Lewandowski

    2003-04-25

    A multi-grid part-in-cell algorithm for a shearless slab drift wave model with kinetic electrons is presented. The algorithm, which is based on an exact separation of adiabatic and nonadiabatic electron responses, is used to investigate the presence of strange attractors in drift wave turbulence. Although the simulation model has a large number of degrees of freedom, it is found that the strange attractor is low-dimensional and that it is strongly affected by dissipative (collisional) effects.

  6. Strangeness in the Meson Cloud Model

    SciTech Connect

    Signal, A. I.

    2010-07-27

    I review progress in calculating strange quark and antiquark distributions of the nucleon using the meson cloud model. This progress parallels that of the meson cloud model, which is now a useful theoretical basis for understanding symmetry breaking in nucleon parton distribution functions. I examine the breaking of symmetries involving strange quarks and antiquarks, including quark--antiquark symmetry in the sea, SU(3) flavour symmetry and SU(6) spin-flavour symmetry.

  7. Strangeness Physics with CLAS at Jefferson Lab

    SciTech Connect

    Burkert, Volker

    2009-10-01

    A brief overview of strangeness physics with the CLAS detector at JLab is given, mainly covering the domain of nucleon resonances. Several excited states predicted by the symmetric constituent quark model may have signiffcant couplings to the K+ or K0 channels. I will discuss data that are relevant in the search for such states in the strangeness channel, and give an outlook on the future prospects of the N* program at JLab with electromagnetic probes.

  8. Factors influencing survival duration and choice of virgin queens in the stingless bee Melipona quadrifasciata

    NASA Astrophysics Data System (ADS)

    Kärcher, Martin H.; Menezes, Cristiano; Alves, Denise A.; Beveridge, Oliver S.; Imperatriz-Fonseca, Vera-Lucia; Ratnieks, Francis L. W.

    2013-06-01

    In Melipona quadrifasciata, about 10 % of the females develop into queens, almost all of which are killed. Occasionally, a new queen replaces or supersedes the mother queen or heads a new colony. We investigated virgin queen fate in queenright and queenless colonies to determine the effects of queen behaviour, body mass, nestmate or non-nestmate status, queenright or queenless colony status, and, when queenless, the effect of the time a colony had been queenless, on survival duration and acceptance. None of 220 virgin queens observed in four observation hives ever attacked another virgin queen nor did any of 88 virgin queens introduced into queenright colonies ever attack the resident queen. A new queen was only accepted in a queenless colony. Factors increasing survival duration and acceptance of virgin queens were to emerge from its cell at 2 h of queenlessness, to hide, and to avoid fights with workers. In this way, a virgin queen was more likely to be available when a colony chooses a new queen, 24-48 h after resident queen removal. Running, walking or resting, antennating or trophallaxis, played little or no role, as did the factors body mass or nestmate. "Queen choice" took about 2 h during which time other virgin queens were still being killed by workers. During this agitated process, the bees congregated around the new queen. She inflated her abdomen and some of the workers deposited a substance on internal nest surfaces including the glass lid of the observation hive.

  9. Queen pheromones: The chemical crown governing insect social life.

    PubMed

    Holman, Luke

    2010-11-01

    Group-living species produce signals that alter the behavior and even the physiology of their social partners. Social insects possess especially sophisticated chemical communication systems that govern every aspect of colony life, including the defining feature of eusociality: reproductive division of labor. Current evidence hints at the central importance of queen pheromones, but progress has been hindered by the fact that such pheromones have only been isolated in honeybees. In a pair of papers on the ant Lasius niger, we identified and investigated a queen pheromone regulating worker sterility. The cuticular hydrocarbon 3-methylhentriacontane (3-MeC(31)) is correlated with queen maturity and fecundity and workers are also more likely to execute surplus queens that have low amounts of this chemical. Experiments with synthetic 3-MeC(31) found that it inhibits ovarian development in queenless workers and lowers worker aggression towards objects coated with it. Production of 3-MeC(31) by queens was depressed by an experimental immune challenge, and the same chemical was abundant on queenlaid eggs, suggesting that the workers' responses to the queen are conditional on her health and fecundity. Together with other studies, these results indicate that queen pheromones are honest signals of quality that simultaneously regulate multiple social behaviors. PMID:21331238

  10. Mandibular gland components of european and africanized honey bee queens (Apis mellifera L.).

    PubMed

    Pankiw, T; Winston, M L; Plettner, E; Slessor, K N; Pettis, J S; Taylor, O R

    1996-04-01

    The composition of the five-component honey bee queen mandibular gland pheromone (QMP) of mated European honey bee queens was compared to those of virgin and drone-laying (i.e., laying only haploid unfertilized eggs that develop into males), European queens and Africanized mated queens. QMP of mated European queens showed significantly greater quantities of individual components than all queen types compared, except for a significantly greater quantity of 9-hydroxy-(E)-2-decenoic acid (9-HDA) found in Africanized queens. Glands of European drone-laying queens contained quantities intermediate between virgin and mated queens, reflecting their intermediate reproductive state and age. QMP ontogeny shifts from a high proportion of 9-keto-(E)-2-decenoic acid (ODA) in young unmated queens to roughly equal proportions of ODA and 9-HDA in mated queens. A biosynthetic shift occurs after mating that results in a greater proportion of 9-HDA, methylp-hydroxybenzoate (HOB), and 4-hydroxy-3-methoxyphenylethanol (HVA) production, accompanied by a decreased proportion of ODA. Africanized QMP proportions of ODA and 9-HDA were significantly different from European queens. A quantitative definition of a "queen equivalent" of QMP is proposed for the various queen types, and a standard queen equivalent for mated European honeybee queen mandibular gland pheromone is adopted as 200µg ODA, 80µg 9-HDA, 20µg HOB, and 2 µg HVA. PMID:24227572

  11. Theoretical perspectives on strange physics

    SciTech Connect

    Ellis, J.

    1983-04-01

    Kaons are heavy enough to have an interesting range of decay modes available to them, and light enough to be produced in sufficient numbers to explore rare modes with satisfying statistics. Kaons and their decays have provided at least two major breakthroughs in our knowledge of fundamental physics. They have revealed to us CP violation, and their lack of flavor-changing neutral interactions warned us to expect charm. In addition, K/sup 0/-anti K/sup 0/ mixing has provided us with one of our most elegant and sensitive laboratories for testing quantum mechanics. There is every reason to expect that future generations of kaon experiments with intense sources would add further to our knowledge of fundamental physics. This talk attempts to set future kaon experiments in a general theoretical context, and indicate how they may bear upon fundamental theoretical issues. A survey of different experiments which would be done with an Intense Medium Energy Source of Strangeness, including rare K decays, probes of the nature of CP isolation, ..mu.. decays, hyperon decays and neutrino physics is given. (WHK)

  12. Strangeness Production at Jefferson Lab

    SciTech Connect

    Raue, Brian

    2003-11-01

    The Thomas Jefferson National Accelerator Facility has an extensive program of studying the electromagnetic production of strange particles. One of the main components of this program has been the study of both photo- and electropro- duction of K+ + â º0 and K+ + Å 0 final states. Experiments are being, or have been conducted in all three of Jefferson Lab s experimental halls measuring a wide range of observables at kinematics from threshold up to W H 3.0 GeV and Q2 from 0.4 up to 5 (GeV/c)2. The largest effort in this endeavor is taking place in Hall B using the CEBAF Large Acceptance Spectrometer (CLAS). Data have been taken at about ten different polarized electron beam energies and are currently being analyzed. Preliminary results [1] for one beam energy exist wherein the unpolarized cross section has been separated into three components: AT + eLAL, ATT , and ALT . The data indicate a t-channel dominance for the â º0 production and a strong s-channel dominance for Å 0 produc

  13. Strange hadron production at low transverse momenta

    NASA Astrophysics Data System (ADS)

    Veres, Gábor I.; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wyslouch, B.; Zhang, J.

    2004-01-01

    Some of the latest results of the PHOBOS experiment from the \\sqrt{s_{NN}}= 200\\ GeV Au+Au data are discussed. Those relevant to strangeness production are emphasized. These observations relate to the nature of the matter created when heavy ions collide at the highest achieved energy. The invariant yields of strange and non-strange charged hadrons at very low transverse momentum have been measured, and used to differentiate between different dynamical scenarios. In the intermediate transverse momentum range, the measured ratios of strange and anti-strange kaons approach one, while the antibaryon to baryon ratio is still significantly less, independent of collision centrality and transverse momentum. At high transverse momenta, we find that central and peripheral Au+Au collisions produce similar numbers of charged hadrons per participant nucleon pair, rather than per binary nucleon-nucleon collision. Finally, we describe the upgrades of PHOBOS completed for the 2003 d+Au and p+p run, which extend the transverse momentum range over which particle identification is possible and, at the same time, implement a trigger system selective for high-pT particles.

  14. Radar detection of drones responding to honeybee queen pheromone.

    PubMed

    Loper, G M; Wolf, W W; Taylor, O R

    1993-09-01

    The response of honey bee (Apis mellifera L.) drones to queen pheromone(s) (either natural from a mated queen, or synthetic from a lure) was recorded using an X-band, ground-based radar. The distribution of drones (insect targets on the radar screen) changed from a scattered distribution to a line concentration (downwind) when the pheromone was released. Displacement within the line concentration was toward the pheromone. This response was seen as far as 800±15 m downwind from a lure with 10 mg of synthetic 9-oxodec-trans-2-enoic acid (9-ODA) and as far as 420±15 m from a mated queen. These studies demonstrate that queen pheromone can be detected by drones at much greater distances than previously believed and illustrate how X-band radar may be used to establish the distances at which insects of similar or larger size respond to pheromones. PMID:24249369

  15. Queens become workers: pesticides alter caste differentiation in bees.

    PubMed

    Dos Santos, Charles F; Acosta, André L; Dorneles, Andressa L; Dos Santos, Patrick D S; Blochtein, Betina

    2016-01-01

    Bees are important for the world biodiversity and economy because they provide key pollination services in forests and crops. However, pesticide use in crops has adversely affected (decreased) queen production because of increased mortality among larvae. Here, we demonstrated that in vitro-reared queens of a neotropical social bee species (Plebeia droryana) also showed high larval mortality after exposure to an organophosphate pesticide (chlorpyrifos) via larval food. Moreover, most of the surviving larvae that were destined to develop into queens became workers more likely because they ate less food than expected without pesticide skewing thus caste differentiation in this bee species. This adverse effect has not been previously reported for any other social insects, such as honeybees or bumblebees. Queens are essential for breeding and colony growth. Therefore, if our data are applicable to other pantropical social bee species across the globe, it is likely that these bees are at a serious risk of failure to form new colonies. PMID:27530246

  16. Queens become workers: pesticides alter caste differentiation in bees

    PubMed Central

    dos Santos, Charles F.; Acosta, André L.; Dorneles, Andressa L.; dos Santos, Patrick D. S.; Blochtein, Betina

    2016-01-01

    Bees are important for the world biodiversity and economy because they provide key pollination services in forests and crops. However, pesticide use in crops has adversely affected (decreased) queen production because of increased mortality among larvae. Here, we demonstrated that in vitro-reared queens of a neotropical social bee species (Plebeia droryana) also showed high larval mortality after exposure to an organophosphate pesticide (chlorpyrifos) via larval food. Moreover, most of the surviving larvae that were destined to develop into queens became workers more likely because they ate less food than expected without pesticide skewing thus caste differentiation in this bee species. This adverse effect has not been previously reported for any other social insects, such as honeybees or bumblebees. Queens are essential for breeding and colony growth. Therefore, if our data are applicable to other pantropical social bee species across the globe, it is likely that these bees are at a serious risk of failure to form new colonies. PMID:27530246

  17. A Critical Look at the Queen Bee Syndrome

    ERIC Educational Resources Information Center

    Berry, Jane; Kushner, Richard

    1975-01-01

    Discusses the popular "Queen Bee" stereotype of successful female executives, and concludes that the stereotype is too narrow in focus and fails to take into account complex psychological and experiential variables. (Author/EJT)

  18. 75 FR 54419 - Environmental Impact Statement: Queens County, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-07

    ... Federal Highway Administration Environmental Impact Statement: Queens County, NY AGENCY: Federal Highway... Environmental Impact Statement (EIS) for the proposed Bridge Rehabilitation and Interchange Improvements Project... considered will not have a significant impact on the environment. To address these bridge conditions,...

  19. Maternal influence on the acceptance of virgin queens introduced into Africanized honey bee (Apis mellifera) colonies.

    PubMed

    Moretto, G; Guerra, J C V; Kalvelage, H; Espindola, E

    2004-01-01

    The oviposition potential of honey bee queens decreases with age, therefore it is important to replace old queens with younger ones on a periodic basis. However, queen replacement is problematic, especially in Africanized honey bee colonies, since many introduced queens are not accepted, and virgin queens are less easily accepted than are mated queens. We assessed the influence of genetic origin (queen mother) on the acceptance of queens, when they were introduced as virgins into Africanized honey bee colonies. For this purpose, 12 daughter queens from each of 11 mother queens with no degree of kinship among themselves were introduced. Introductions were made monthly, for 12 months, though the winter months of June and July were not included, as there is little brood and drones are rare in winter. There was some seasonal variation in the acceptance rates; generally there was greater acceptance in months with good honey flows. However, the acceptance of introduced queens was influenced by their origin. The rate of acceptance of daughter queens from the 11 different mother queens varied significantly, ranging from 33 to 75%. There appears to be a genetic influence of the mother queen on the introduced queen acceptance rate. PMID:15614734

  20. Mating triggers dynamic immune regulations in wood ant queens.

    PubMed

    Castella, G; Christe, P; Chapuisat, M

    2009-03-01

    Mating can affect female immunity in multiple ways. On the one hand, the immune system may be activated by pathogens transmitted during mating, sperm and seminal proteins, or wounds inflicted by males. On the other hand, immune defences may also be down-regulated to reallocate resources to reproduction. Ants are interesting models to study post-mating immune regulation because queens mate early in life, store sperm for many years, and use it until their death many years later, while males typically die after mating. This long-term commitment between queens and their mates limits the opportunity for sexual conflict but raises the new constraint of long-term sperm survival. In this study, we examine experimentally the effect of mating on immunity in wood ant queens. Specifically, we compared the phenoloxidase and antibacterial activities of mated and virgin Formica paralugubris queens. Queens had reduced levels of active phenoloxidase after mating, but elevated antibacterial activity 7 days after mating. These results indicate that the process of mating, dealation and ovary activation triggers dynamic patterns of immune regulation in ant queens that probably reflect functional responses to mating and pathogen exposure that are independent of sexual conflict. PMID:19170815

  1. Unequal subfamily proportions among honey bee queen and worker brood

    PubMed

    Tilley; Oldroyd

    1997-12-01

    Queens from three colonies of feral honey bees, Apis mellifera were removed and placed in separate nucleus colonies. For each colony, eggs and larvae were taken from the nucleus and placed in the main hive on each of 3-4 consecutive weeks. Workers in the queenless parts selected young larvae to rear as queens. Queen pupae, together with the surrounding worker pupae, were removed from each colony and analysed at two to three microsatellite loci to determine their paternity. In all three colonies, the paternity of larvae chosen by the bees to rear as queens was not a random sample of the paternities in the worker brood, with certain subfamilies being over-represented in queens. These results support an important prediction of kin selection theory: when colonies are queenless, unequal relatedness within colonies could lead to the evolution of reproductive competition, that is some subfamilies achieving greater reproductive success than others. The mechanism by which such dominance is achieved could be through a system of kin recognition and nepotism, but we conclude that genetically based differential attractiveness of larvae for rearing as queens is more likely.Copyright 1997 The Association for the Study of Animal BehaviourCopyright 1997The Association for the Study of Animal Behaviour. PMID:9521799

  2. Asexual queen succession in the higher termite Embiratermes neotenicus

    PubMed Central

    Fougeyrollas, Romain; Dolejšová, Klára; Sillam-Dussès, David; Roy, Virginie; Poteaux, Chantal; Hanus, Robert; Roisin, Yves

    2015-01-01

    Asexual queen succession (AQS), in which workers, soldiers and dispersing reproductives are produced sexually while numerous non-dispersing queens arise through thelytokous parthenogenesis, has recently been described in three species of lower termites of the genus Reticulitermes. Here, we show that AQS is not an oddity restricted to a single genus of lower termites, but a more widespread strategy occurring also in the most advanced termite group, the higher termites (Termitidae). We analysed the genetic structure in 10 colonies of the Neotropical higher termite Embiratermes neotenicus (Syntermitinae) using five newly developed polymorphic microsatellite loci. The colonies contained one primary king accompanied either by a single primary queen or by up to almost 200 neotenic queens. While the workers, the soldiers and most future dispersing reproductives were produced sexually, the non-dispersing neotenic queens originated through thelytokous parthenogenesis of the founding primary queen. Surprisingly, the mode of thelytoky observed in E. neotenicus is most probably automixis with central fusion, contrasting with the automixis with terminal fusion documented in Reticulitermes. The occurrence of AQS based on different mechanisms of ploidy restoration raises the hypothesis of an independent evolutionary origin of this unique reproductive strategy in individual lineages of lower and higher termites. PMID:26019158

  3. Measurements of strangeness production in the STAR experiment at RHIC

    SciTech Connect

    Wilson, W.K.

    1995-07-15

    Simulations of the ability of the STAR (Solenoidal Tracker at RHIC) detector to measure strangeness production in central Au+Au collisions at RHIC are presented. Emphasis is placed on the reconstruction of short lived particles using a high resolution inner tracker. The prospects for performing neutral kaon interferometry are discussed. Simulation results for measurements of strange and multi-strange baryons are presented.

  4. Recent results from strangeness in transport models

    NASA Astrophysics Data System (ADS)

    Steinheimer, J.; Botvina, A. S.; Bleicher, M.

    2016-01-01

    In these proceedings we discuss recent developments in the microscopic description of strange particle production in nuclear collisions. We put a special emphasis on the production of hypernuclei at the upcoming FAIR and NICA facilities as well as the deep sub threshold, ϕ and Ξ- production yields measured with the HADES experiment. Employing new resonance decay channels we obtain a satisfactory description of ϕ and Ξ- production in deep sub threshold Ar+KCl reactions. Our results implicate that no new medium effects are required to describe the rare strange particle production data from low energy nuclear collisions.

  5. Some analytical models of anisotropic strange stars

    NASA Astrophysics Data System (ADS)

    Murad, Mohammad Hassan

    2016-01-01

    Over the years of the concept of local isotropy has become a too stringent condition in modeling relativistic self-gravitating objects. Taking local anisotropy into consideration, in this work, some analytical models of relativistic anisotropic charged strange stars have been developed. The Einstein-Maxwell gravitational field equations have been solved with a particular form of one of the metric potentials. The radial pressure and the energy density have been assumed to follow the usual linear equation of state of strange quark matter, the MIT bag model.

  6. Connecting coherent structures and strange attractors

    NASA Technical Reports Server (NTRS)

    Keefe, Laurence R.

    1990-01-01

    A concept of turbulence derived from nonlinear dynamical systems theory suggests that turbulent solutions to the Navier-Stokes equations are restricted to strange attractors, and, by implication, that turbulent phenomenology must find some expression or source in the structure of these mathematical objects. Examples and discussions are presented to link coherent structures to some of the commonly known characteristics of strange attractors. Basic to this link is a geometric interpretation of conditional sampling techniques employed to educe coherent structures that offers an explanation for their appearance in measurements as well as their size.

  7. Virgin honeybee queens fail to suppress worker fertility but not fertility signalling.

    PubMed

    Orlova, Margarita; Malka, Osnat; Hefetz, Abraham

    2013-03-01

    Queen mating status in social insects is a matter of crucial importance for workers because of its influence on the queen's productivity and consequently their fitness. Behavioural and physiological reactions of workers to the queens mating status have been studied as a proxy to mechanisms maintaining insect sociality. Here we show that unmated honeybee queens have considerably impaired capacity to trigger worker sterility and cooperative behaviour in comparison to mated (and thus more productive) queens and that under unmated queens social harmony in honeybee societies and queen's dominant position are somewhat compromised. Together with this it is shown that honeybee workers exposed to unmated queens despite being active reproductively and behaving accordingly display an impaired ability to advertise their fertility compared to queenless workers. These findings suggest that reproductive development, behavioural reactions and production of fertility signals are differentially regulated and differently influenced by the queen's presence. PMID:23232436

  8. Multifunctional queen pheromone and maintenance of reproductive harmony in termite colonies.

    PubMed

    Matsuura, Kenji

    2012-06-01

    Pheromones are likely involved in all social activities of social insects including foraging, sexual behavior, defense, nestmate recognition, and caste regulation. Regulation of the number of fertile queens requires communication between reproductive and non-reproductive individuals. Queen-produced pheromones have long been believed to be the main factor inhibiting the differentiation of new reproductive individuals. However, since the discovery more than 50 years ago of the queen honeybee substance that inhibits the queen-rearing behavior of workers, little progress has been made in the chemical identification of inhibitory queen pheromones in other social insects. The recent identification of a termite queen pheromone and subsequent studies have elucidated the multifaceted roles of volatile pheromones, including functions such as a fertility signal, worker attractant, queen-queen communication signal, and antimicrobial agent. The proximate origin and evolutionary parsimony of the termite queen pheromone also are discussed. PMID:22623152

  9. Exact strangeness conservation and particle production

    NASA Astrophysics Data System (ADS)

    Cleymans, J.; Redlich, K.; Suhonen, E.

    The production of strange particles is studied in terms of a statistical formalism requiring strangeness to be exactly conserved while baryon number is treated grand canonically using a chemical potential. The gas is considered to be in thermal and chemical equilibrium and to have zero overall strangeness. All particles and resonances having masses up to approximately 2 GeV and strangeness up to plus or minus 3 are included. General formulas for different particle multiplicities in terms of infinite series of modified Bessel functions are derived. In contrast to the integral representation of particle numbers in the canonical ensemble, results can be easily handled numerically since the series converge very rapidly. As an illustration, the above formalism is applied to the description of particle production in proton-proton, proton-nucleus and nucleus-nucleus collisions. In particular the K/pi ratio shows a strong dependence on the interaction volume on the system while, in contrast, the antiLambda/Lambda ratio is almost independent of the volume. These results are in qualitative agreement with experimental data.

  10. Seismic Search for Strange Quark Matter

    NASA Technical Reports Server (NTRS)

    Teplitz, Vigdor

    2004-01-01

    Two decades ago, Witten suggested that the ground state of matter might be material of nuclear density made from up, down and strange quarks. Since then, much effort has gone into exploring astrophysical and other implications of this possibility. For example, neutron stars would almost certainly be strange quark stars; dark matter might be strange quark matter. Searches for stable strange quark matter have been made in various mass ranges, with negative, but not conclusive results. Recently, we [D. Anderson, E. Herrin, V. Teplitz, and I. Tibuleac, Bull. Seis. Soc. of Am. 93, 2363 (2003)] reported a positive result for passage through the Earth of a multi-ton "nugget" of nuclear density in a search of about a million seismic reports, to the U.S. Geological Survey for the years 1990-93, not associated with known Earthquakes. I will present the evidence (timing of first signals to the 9 stations involved, first signal directions, and unique waveform characteristics) for our conclusion and discuss potential improvements that could be obtained from exploiting the seismologically quieter environments of the moon and Mars.

  11. Last orbits of binary strange quark stars

    SciTech Connect

    Limousin, Francois; Gourgoulhon, Eric; Gondek-Rosinska, Dorota

    2005-03-15

    We present the first relativistic calculations of the final phase of inspiral of a binary system consisting of two stars built predominantly of strange quark matter (strange quark stars). We study the precoalescing stage within the Isenberg-Wilson-Mathews approximation of general relativity using a multidomain spectral method. A hydrodynamical treatment is performed under the assumption that the flow is either rigidly rotating or irrotational, taking into account the finite density at the stellar surface--a distinctive feature with respect to the neutron star case. The gravitational-radiation driven evolution of the binary system is approximated by a sequence of quasiequilibrium configurations at fixed baryon number and decreasing separation. We find that the innermost stable circular orbit (ISCO) is given by an orbital instability both for synchronized and irrotational systems. This contrasts with neutron stars for which the ISCO is given by the mass-shedding limit in the irrotational case. The gravitational wave frequency at the ISCO, which marks the end of the inspiral phase, is found to be {approx}1400 Hz for two irrotational 1.35 M{sub {center_dot}} strange stars and for the MIT bag model of strange matter with massless quarks and a bag constant B=60 MeV fm{sup -3}. Detailed comparisons with binary neutrons star models, as well as with third order post-Newtonian point-mass binaries are given.

  12. 'Strange money': risk, finance and socialized debt.

    PubMed

    Dodd, Nigel

    2011-03-01

    This paper explores an essential but neglected aspect of recent discussions of the banking and financial system, namely money itself. Specifically, I take up a distinction drawn by Susan Strange which has never been fully elaborated: between a financial system that is global, and an international monetary system that remains largely territorial. I propose a sociological elaboration of this distinction by examining each category, 'finance' and 'money', in terms of its distinctive orientation to risk and debt. Money is distinguished by its high degree of liquidity and low degree of risk, corresponding to expectations that derive from its status as a 'claim upon society'- a form of socialized debt. But as Strange argued, these features of money are being undermined by the proliferation of sophisticated instruments of financial risk management -'strange money'- that, as monetary substitutes, both weaken states' capacity to manage money, and more broadly, contribute to 'overbanking'. The ultimate danger, according to Strange, is the 'death of money'. The paper concludes by exploring the implications of the distinction for sociological arguments about the changing nature of money. PMID:21361907

  13. The evolution of queen pheromones in the ant genus Lasius.

    PubMed

    Holman, L; Lanfear, R; d'Ettorre, P

    2013-07-01

    Queen pheromones are among the most important chemical messages regulating insect societies yet they remain largely undiscovered, hindering research into interesting proximate and ultimate questions. Identifying queen pheromones in multiple species would give new insight into the selective pressures and evolutionary constraints acting on these ubiquitous signals. Here, we present experimental and comparative evidence that 3-methylalkanes, hydrocarbons present on the queen's cuticle, are a queen pheromone throughout the ant genus Lasius. Interspecific variation in the chemical profile is consistent with 3-methylalkanes evolving more slowly than other types of hydrocarbons, perhaps due to differential selection or evolutionary constraints. We argue that the sensory ecology of the worker response imposes strong stabilizing selection on queen pheromones relative to other hydrocarbons. 3-Methylalkanes are also strongly physiologically and genetically coupled with fecundity in at least one Lasius species, which may translate into evolutionary constraints. Our results highlight how honest signalling could minimize evolutionary conflict over reproduction, promoting the evolution and maintenance of eusociality. PMID:23662630

  14. Bumblebee size polymorphism and worker response to queen pheromone

    PubMed Central

    2014-01-01

    Queen pheromones are chemical signals produced by reproductive individuals in social insect colonies. In many species they are key to the maintenance of reproductive division of labor, with workers beginning to reproduce individually once the queen pheromone disappears. Recently, a queen pheromone that negatively affects worker fecundity was discovered in the bumblebee Bombus terrestris, presenting an exciting opportunity for comparisons with analogous queen pheromones in independently-evolved eusocial lineages such as honey bees, ants, wasps and termites. I set out to replicate this discovery and verify its reproducibility. Using blind, controlled experiments, I found that n-pentacosane (C25) does indeed negatively affect worker ovary development. Moreover, the pheromone affects both large and small workers, and applies to workers from large, mature colonies as well as young colonies. Given that C25 is readily available and that bumblebees are popular study organisms, I hope that this replication will encourage other researchers to tackle the many research questions enabled by the discovery of a queen pheromone. PMID:25289189

  15. Presence of Nosema ceranae associated with honeybee queen introductions.

    PubMed

    Muñoz, Irene; Cepero, Almudena; Pinto, Maria Alice; Martín-Hernández, Raquel; Higes, Mariano; De la Rúa, Pilar

    2014-04-01

    Microsporidiosis caused by Nosema species is one of the factors threatening the health of the honeybee (Apis mellifera), which is an essential element in agriculture mainly due to its pollination function. The dispersion of this pathogen may be influenced by many factors, including various aspects of beekeeping management such as introduction of queens with different origin. Herein we study the relation of the presence and distribution of Nosema spp. and the replacement of queens in honeybee populations settled on the Atlantic Canary Islands. While Nosema apis has not been detected, an increase of the presence and distribution of Nosema ceranae during the last decade has been observed in parallel with a higher frequency of foreign queens. On the other hand, a reduction of the number of N. ceranae positive colonies was observed on those islands with continued replacement of queens. We suggest that such replacement could help maintaining low rates of Nosema infection, but healthy queens native to these islands should be used in order to conserve local honeybee diversity. PMID:24568841

  16. Bumblebee size polymorphism and worker response to queen pheromone.

    PubMed

    Holman, Luke

    2014-01-01

    Queen pheromones are chemical signals produced by reproductive individuals in social insect colonies. In many species they are key to the maintenance of reproductive division of labor, with workers beginning to reproduce individually once the queen pheromone disappears. Recently, a queen pheromone that negatively affects worker fecundity was discovered in the bumblebee Bombus terrestris, presenting an exciting opportunity for comparisons with analogous queen pheromones in independently-evolved eusocial lineages such as honey bees, ants, wasps and termites. I set out to replicate this discovery and verify its reproducibility. Using blind, controlled experiments, I found that n-pentacosane (C25) does indeed negatively affect worker ovary development. Moreover, the pheromone affects both large and small workers, and applies to workers from large, mature colonies as well as young colonies. Given that C25 is readily available and that bumblebees are popular study organisms, I hope that this replication will encourage other researchers to tackle the many research questions enabled by the discovery of a queen pheromone. PMID:25289189

  17. Do sexist organizational cultures create the Queen Bee?

    PubMed

    Derks, Belle; Ellemers, Naomi; van Laar, Colette; de Groot, Kim

    2011-09-01

    'Queen Bees' are senior women in masculine organizational cultures who have fulfilled their career aspirations by dissociating themselves from their gender while simultaneously contributing to the gender stereotyping of other women. It is often assumed that this phenomenon contributes to gender discrimination in organizations, and is inherent to the personalities of successful career women. We argue for a social identity explanation and examine organizational conditions that foster the Queen Bee phenomenon. Participants were 94 women holding senior positions in diverse companies in The Netherlands who participated in an on-line survey. In line with predictions, indicators of the Queen Bee phenomenon (increased gender stereotyping and masculine self-descriptions) were found mostly among women who indicated they had started their career with low gender identification and who had subsequently experienced a high degree of gender discrimination on their way up. By contrast, the experience of gender discrimination was unrelated to signs of the Queen Bee phenomenon among women who indicated to be highly identified when they started their career. Results are discussed in light of social identity theory, interpreting the Queen Bee phenomenon as an individual mobility response of low gender identified women to the gender discrimination they encounter in their work. PMID:21884548

  18. Venom alkaloid and cuticular hydrocarbon profiles are associated with social organization, queen fertility status, and queen genotype in the fire ant Solenopsis invicta.

    PubMed

    Eliyahu, Dorit; Ross, Kenneth G; Haight, Kevin L; Keller, Laurent; Liebig, Jürgen

    2011-11-01

    Queens in social insect colonies advertise their presence in the colony to: a) attract workers' attention and care; b) gain acceptance by workers as replacement or supplemental reproductives; c) prevent reproductive development in nestmates. We analyzed the chemical content of whole body surface extracts of adult queens of different developmental and reproductive stages, and of adult workers from monogyne (single colony queen) and polygyne (multiple colony queens) forms of the fire ant Solenopsis invicta. We found that the composition of the most abundant components, venom alkaloids, differed between queens and workers, as well as between reproductive and non-reproductive queens. Additionally, workers of the two forms could be distinguished by alkaloid composition. Finally, sexually mature, non-reproductive queens from polygyne colonies differed in their proportions of cis-piperidine alkaloids, depending on their Gp-9 genotype, although the difference disappeared once they became functional reproductives. Among the unsaturated cuticular hydrocarbons characteristic of queens, there were differences in amounts of alkenes/alkadienes between non-reproductive polygyne queens of different Gp-9 genotypes, between non-reproductive and reproductive queens, and between polygyne and monogyne reproductive queens, with the amounts increasing at a relatively higher rate through reproductive ontogeny in queens bearing the Gp-9 b allele. Given that the genotype-specific piperidine differences reflect differences in rates of reproductive maturation between queens, we speculate that these abundant and unique compounds have been co-opted to serve in fertility signaling, while the cuticular hydrocarbons now play a complementary role in regulation of social organization by signaling queen Gp-9 genotype. PMID:22095515

  19. The value of oviposition timing, queen presence and kinship in a social insect

    PubMed Central

    Ozan, Martina; Helanterä, Heikki; Sundström, Liselotte

    2013-01-01

    Reproductive cooperation confers benefits, but simultaneously creates conflicts among cooperators. Queens in multi-queen colonies of ants share a nest and its resources, but reproductive competition among queens often results in unequal reproduction. Two mutually non-exclusive factors may produce such inequality in reproduction: worker intervention or queen traits. Workers may intervene by favouring some queens over others, owing to either kinship or queen signals. Queens may differ in their intrinsic fecundity at the onset of oviposition or in their timing of the onset of oviposition, leading to their unequal representation in the brood. Here, we test the role of queen kin value (relatedness) to workers, timing of the onset of oviposition and signals of presence by queens in determining the maternity of offspring. We show that queens of the ant Formica fusca gained a significantly higher proportion of sexuals in the brood when ovipositing early, and that the presence of a caged queen resulted in a significant increase in both her share of sexual brood and her overall reproductive share. Moreover, the lower the kin value of the queen, the more the workers invested in their own reproduction by producing males. Our results show that both kinship and breeding phenology influence the outcome of reproductive conflicts, and the balance of direct and indirect fitness benefits in the multi-queen colonies of F. fusca. PMID:23843391

  20. The role of queens in colonies of the swarm-founding wasp Parachartergus colobopterus.

    PubMed

    Herman; Queller; Strassmann

    2000-04-01

    Social insect queens reproduce while workers generally do not. Queens may also have other behavioural roles in the colony. In small, independent-founding colonies of social wasps, the dominant queen physically enforces her interests over those of the workers and serves as a pacemaker of the colony, stimulating workers to forage and engage in other tasks. By contrast, in large-colony, swarm-founding wasps, the collective interests of the workers are fulfilled in sex allocation and production of males, whether or not they coincide with the interests of the queens. The behavioural role of the queens in such species has not been extensively studied. We investigated the role of the queens both in regulating worker activity and in reducing the numbers of reproductively active queens in the swarm-founding epiponine wasp Parachartergus colobopterus. We found no evidence that queens regulate worker activity, as they were rarely involved in any interactions. Worker activity may be self-organized, without centralized active control by anyone. Furthermore, we found no evidence that the reduction in queen number characteristic of this tribe of wasps occurs in response to aggression among queens. The reduction in queen number may be a result of worker treatment of queens, although worker discrimination against some queens was not obvious in our data. i Copyright 2000 The Association for the Study of Animal Behaviour. PMID:10792939

  1. How many gamergates is an ant queen worth?

    NASA Astrophysics Data System (ADS)

    Monnin, Thibaud; Peeters, Christian

    2008-02-01

    Ant reproductives exhibit different morphological adaptations linked to dispersal and fertility. By reviewing the literature on taxa where workers can reproduce sexually (i.e. become gamergates) we show that (1) species with a single gamergate generally have lost the winged queen caste, whereas only half of the species with several gamergates have, and (2) single-gamergate species have smaller colonies than multiple-gamergate species. Comparison with “classical” ants without gamergates, where having one vs having several winged queens are two distinct syndromes, suggests that having one vs having several gamergates are not. Gamergate number does not affect the success of colony fission, but retention of the queen caste permits the option of independent foundation.

  2. 76 FR 2438 - Culturally Significant Objects Imported for Exhibition Determinations: “Kings, Queens, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-13

    ... the exhibition ``Kings, Queens, and Courtiers: Art in Early Renaissance France'' imported from abroad... Culturally Significant Objects Imported for Exhibition Determinations: ``Kings, Queens, and Courtiers: Art in Early Renaissance France'' SUMMARY: Notice is hereby given of the following determinations: Pursuant...

  3. Visible and near-infrared spectroscopy detects queen honey bee insemination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The abdomens of honey bee queens, the heads of worker bees, and the ventriculi of worker bees were analyzed by visible and near-infrared spectroscopy. Mated honey bee queens could be distinguished from virgin queens by their spectra with 100% accuracy. Also, the heads of worker bees taken from the...

  4. Selection against Aerial Dispersal in Ants: Two Non-Flying Queen Phenotypes in Pogonomyrmex laticeps

    PubMed Central

    Peeters, Christian; Keller, Roberto A.; Johnson, Robert A.

    2012-01-01

    The South American seed-harvester ant Pogonomyrmex laticeps has dimorphic queens: ergatoid (permanently wingless) and brachypterous (short, non-functional wings). Surveys in western Argentina indicated that colonies near Chilecito, La Rioja Province, produced only ergatoid queens, while those near Punta Balasto, Catamarca Province (263 km away), produced only brachypterous queens. Brachypterous queens were significantly larger than ergatoid queens for 10 of 11 external characters, but both phenotypes had comparable reproductive potential, i.e., a spermatheca and a similar number of ovarioles. Using normal winged queens of the closely related P. uruguayensis for comparison, we determined that both queen phenotypes in P. laticeps had a full set of dorsal thoracic sclerites, albeit each sclerite was much reduced, whereas workers had a thorax without distinct dorsal sclerites. Sclerites were fused and immobile in ergatoid queens, while they were separable and fully articulated in brachypterous queens. Both phenotypes lacked the big indirect flight muscles, but brachypterous queens retained the tiny direct flight muscles. Overall, this dimorphism across populations indicates that there are alternative solutions to selective pressures against flying queens. We lack field data about colony founding strategy (independent or dependent) for either queen phenotype, but colonies at both sites produced numerous gynes, and we infer that all foundresses initiate colonies independently and are obligate foragers. PMID:23110094

  5. Queen movement during colony emigration in the facultatively polygynous ant Pachycondyla obscuricornis

    NASA Astrophysics Data System (ADS)

    Pezon, Antoine; Denis, Damien; Cerdan, Philippe; Valenzuela, Jorge; Fresneau, Dominique

    2005-01-01

    In ants, nest relocations are frequent but nevertheless perilous, especially for the reproductive caste. During emigrations, queens are exposed to predation and face the risk of becoming lost. Therefore the optimal strategy should be to move the queen(s) swiftly to a better location, while maintaining maximum worker protection at all times in the new and old nests. The timing of that event is a crucial strategic issue for the colony and may depend on queen number. In monogynous colonies, the queen is vital for colony survival, whereas in polygynous colonies a queen is less essential, if not dispensable. We tested the null hypothesis that queen movement occurs at random within the sequence of emigration events in both monogynous and polygynous colonies of the ponerine ant Pachycondyla obscuricornis. Our study, based on 16 monogynous and 16 polygynous colony emigrations, demonstrates for the first time that regardless of the number of queens per colony, the emigration serial number of a queen occurs in the middle of all emigration events and adult ant emigration events, but not during brood transport events. It therefore appears that the number of workers in both nests plays an essential role in the timing of queen movement. Our results correspond to a robust colony-level strategy since queen emigration is related neither to colony size nor to queen number. Such an optimal strategy is characteristic of ant societies working as highly integrated units and represents a new instance of group-level adaptive behaviors in social insect colonies.

  6. Deformed wing virus can be transmitted during natural mating in honey bees and infect the queens

    PubMed Central

    Amiri, Esmaeil; Meixner, Marina D.; Kryger, Per

    2016-01-01

    Deformed wing virus is an important contributor to honey bee colony losses. Frequently queen failure is reported as a cause for colony loss. Here we examine whether sexual transmission during multiple matings of queens is a possible way of virus infection in queens. In an environment with high prevalence of deformed wing virus, queens (n = 30) were trapped upon their return from natural mating flights. The last drone’s endophallus (n = 29), if present, was removed from the mated queens for deformed wing virus quantification, leading to the detection of high-level infection in 3 endophalli. After oviposition, viral quantification revealed that seven of the 30 queens had high-level deformed wing virus infections, in all tissues, including the semen stored in the spermathecae. Two groups of either unmated queens (n = 8) with induced egg laying, or queens (n = 12) mated in isolation with drones showing comparatively low deformed wing virus infections served as control. None of the control queens exhibited high-level viral infections. Our results demonstrate that deformed wing virus infected drones are competitive to mate and able to transmit the virus along with semen, which occasionally leads to queen infections. Virus transmission to queens during mating may be common and can contribute noticeably to queen failure. PMID:27608961

  7. The effects of pesticides on queen rearing and virus titers in honey bees (Apis mellifera L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of sublethal pesticide exposure on queen emergence and virus titers were examined. Queen rearing colonies were fed pollen with chlorpyrifos (CPF) alone (pollen-1) and with CPF and the fungicide Pristine® (pollen-2). Fewer queens emerged when larvae from open foraging (i.e., outside) colo...

  8. Deformed wing virus can be transmitted during natural mating in honey bees and infect the queens.

    PubMed

    Amiri, Esmaeil; Meixner, Marina D; Kryger, Per

    2016-01-01

    Deformed wing virus is an important contributor to honey bee colony losses. Frequently queen failure is reported as a cause for colony loss. Here we examine whether sexual transmission during multiple matings of queens is a possible way of virus infection in queens. In an environment with high prevalence of deformed wing virus, queens (n = 30) were trapped upon their return from natural mating flights. The last drone's endophallus (n = 29), if present, was removed from the mated queens for deformed wing virus quantification, leading to the detection of high-level infection in 3 endophalli. After oviposition, viral quantification revealed that seven of the 30 queens had high-level deformed wing virus infections, in all tissues, including the semen stored in the spermathecae. Two groups of either unmated queens (n = 8) with induced egg laying, or queens (n = 12) mated in isolation with drones showing comparatively low deformed wing virus infections served as control. None of the control queens exhibited high-level viral infections. Our results demonstrate that deformed wing virus infected drones are competitive to mate and able to transmit the virus along with semen, which occasionally leads to queen infections. Virus transmission to queens during mating may be common and can contribute noticeably to queen failure. PMID:27608961

  9. Visible and Near-Infrared Spectroscopy Detects Honey Bee Queen Insemination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The abdomens of honey bee queens, the heads of worker bees, and the ventriculi of worker bees were analyzed by visible and near-infrared spectroscopy. Mated honey bee queens could be distinguished from virgin queens by their spectra with 100% accuracy. Also, the heads of worker bees taken from the ...

  10. SEARCH FOR NUCLEI CONTAINING TWO STRANGE QUARKS.

    SciTech Connect

    MAY,M.

    1997-10-13

    This paper discusses a search for nuclei containing two strange quarks performed at Brookhaven National Laboratory. The goals and approach of experiment E885 are reviewed. Preliminary missing mass spectra for a subset of the data are presented, showing sensitivity for {Xi} hypernuclei and H particle searches. Existence of an angular correlation between pions in the sequential decay of {Lambda}{Lambda} hypernuclei is suggested on theoretical grounds.

  11. Strangeness and meson-nucleon sigma terms

    SciTech Connect

    Dahiya, Harleen; Sharma, Neetika

    2011-10-21

    The chiral constituent quark model ({chi}CQM) has been extended to calculate the flavor structure of the nucleon through the meson-nucleon sigma terms which have large contributions from the quark sea and are greatly affected by chiral symmetry breaking and SU(3) symmetry breaking. The hidden strangeness component in the nucleon has also been investigated and its significant contribution is found to be consistent with the recent available experimental observations.

  12. Liquid-gas phase transition in nuclear matter including strangeness

    SciTech Connect

    Wang, P.; Leinweber, D.B.; Williams, A.G.; Thomas, A.W.

    2004-11-01

    We apply the chiral SU(3) quark mean field model to study the properties of strange hadronic matter at finite temperature. The liquid-gas phase transition is studied as a function of the strangeness fraction. The pressure of the system cannot remain constant during the phase transition, since there are two independent conserved charges (baryon and strangeness number). In a range of temperatures around 15 MeV (precise values depending on the model used) the equation of state exhibits multiple bifurcates. The difference in the strangeness fraction f{sub s} between the liquid and gas phases is small when they coexist. The critical temperature of strange matter turns out to be a nontrivial function of the strangeness fraction.

  13. Charmed-strange mesons revisited: Mass spectra and strong decays

    NASA Astrophysics Data System (ADS)

    Song, Qin-Tao; Chen, Dian-Yong; Liu, Xiang; Matsuki, Takayuki

    2015-03-01

    Inspired by the present experimental status of charmed-strange mesons, we perform a systematic study of the charmed-strange meson family in which we calculate the mass spectra of the charmed-strange meson family by taking a screening effect into account in the Godfrey-Isgur model and investigate the corresponding strong decays via the quark pair creation model. These phenomenological analyses of charmed-strange mesons not only shed light on the features of the observed charmed-strange states, but also provide important information on future experimental search for the missing higher radial and orbital excitations in the charmed-strange meson family, which will be a valuable task in LHCb, the forthcoming Belle II, and PANDA.

  14. Strangeness conservation constraints in hadron gas models

    SciTech Connect

    Tiwari, V.K.; Singh, S.K.; Uddin, S.; Singh, C.P.

    1996-05-01

    We examine the implications of the constraints arising due to strangeness conservation on the strangeness production in various existing thermal hadron-gas models. The dependence of strangeness chemical potential {mu}{sub {ital S}} on the baryon chemical potential {mu}{sub {ital B}} and temperature {ital T} is investigated. The incorporation of finite-size, hard-core, repulsive interactions in the thermodynamically consistent description of hot and dense hadron gas alters the results obtained for pointlike particles. We compare results in two extreme alternative cases: (1) {ital K} and {ital K}{sup {asterisk}} mesons are treated as point particles and they can penetrate all volumes occupied by baryons and antibaryons and (2) the volume occupied by the baryons and antibaryons is not accessible to them. We find that the results indeed depend on the assumptions made. Moreover, the anomalous results obtained for the ratios {bar {Xi}}/{Xi} and {bar {Lambda}}/{Lambda} rule out the second possibility. {copyright} {ital 1996 The American Physical Society.}

  15. Strangeness in the baryon ground states

    NASA Astrophysics Data System (ADS)

    Semke, A.; Lutz, M. F. M.

    2012-10-01

    We compute the strangeness content of the baryon octet and decuplet states based on an analysis of recent lattice simulations of the BMW, PACS, LHPC and HSC groups for the pion-mass dependence of the baryon masses. Our results rely on the relativistic chiral Lagrangian and large-Nc sum rule estimates of the counter terms relevant for the baryon masses at N3LO. A partial summation is implied by the use of physical baryon and meson masses in the one-loop contributions to the baryon self energies. A simultaneous description of the lattice results of the BMW, LHPC, PACS and HSC groups is achieved. From a global fit we determine the axial coupling constants F ≃ 0.45 and D ≃ 0.80 in agreement with their values extracted from semi-leptonic decays of the baryons. Moreover, various flavor symmetric limits of baron octet and decuplet masses as obtained by the QCDSF-UKQCD group are recovered. We predict the pion- and strangeness sigma terms and the pion-mass dependence of the octet and decuplet ground states at different strange quark masses.

  16. Strangeness production in AA and pp collisions

    NASA Astrophysics Data System (ADS)

    Castorina, Paolo; Satz, Helmut

    2016-07-01

    Boost-invariant hadron production in high-energy collisions occurs in causally disconnected regions of finite space-time size. As a result, globally conserved quantum numbers (charge, strangeness, baryon number) are conserved locally in spatially restricted correlation clusters. Their size is determined by two time scales: the equilibration time specifying the formation of a quark-gluon plasma, and the hadronization time, specifying the onset of confinement. The expected values for these scales provide the theoretical basis for the suppression observed for strangeness production in elementary interactions ( pp , e^+e^- below LHC energies. In contrast, the space-time superposition of individual collisions in high-energy heavy-ion interactions leads to higher energy densities, resulting in much later hadronization and hence much larger hadronization volumes. This largely removes the causality constraints and results in an ideal hadronic resonance gas in full chemical equilibrium. In the present paper, we determine the collision energies needed for that; we also estimate when pp collisions reach comparable hadronization volumes and thus determine when strangeness suppression should disappear there as well.

  17. Strangeness asymmetry of the nucleon in the statistical parton model

    NASA Astrophysics Data System (ADS)

    Bourrely, Claude; Soffer, Jacques; Buccella, Franco

    2007-04-01

    We extend to the strange quarks and antiquarks, the statistical approach of parton distributions and we calculate the strange quark asymmetry s -sbar. We find that the asymmetry is small, positive in the low x region and negative in the high x region. In this framework, the polarized strange quarks and antiquarks distributions, which are obtained simultaneously, are found to be both negative for all x values.

  18. Docile sitters and active fighters in paper wasps: a tale of two queens

    NASA Astrophysics Data System (ADS)

    Kardile, Sujata; Gadagkar, Raghavendra

    2002-02-01

    Ropalidia marginata and Ropalidia cyathiformis are sympatric, primitively eusocial paper wasps widely distributed in peninsular India. We compare the two species, especially their queens, in an attempt to begin to understand the role of the power of queens over their workers, in social organisation and evolution. Queens of R. marginata have lower levels of activity, rates of interactions and dominance behaviour, compared with queens of R. cyathiformis. For the same variables, R. marginata queens are either indistinguishable from or have lower values than their workers, while R. cyathiformis queens have higher values than their workers. R. marginata queens never occupy the top rank while R. cyathiformis queens are always at the top of the behavioural dominance hierarchies of their colonies. R. marginata queens thus do not appear to use dominance behaviour to suppress reproduction by their workers, while R. cyathiformis queens appear to do so. These different mechanisms used by the two queens to regulate worker reproduction give them different powers over their workers, because R. marginata queens are completely successful in suppressing reproduction by their nestmates while in R. cyathiformis colonies, other individuals also sometimes lay eggs. There is also some evidence that the different powers of the queens result in different mechanisms of regulation of worker foraging in the two species - decentralised, self-regulation in R. marginata and relatively more centralised regulation by the queen in R. cyathiformis. Thus we show here, perhaps for the first time, that the power of the queens over their workers can have important consequences for social organisation and evolution.

  19. Identification of an ant queen pheromone regulating worker sterility.

    PubMed

    Holman, Luke; Jørgensen, Charlotte G; Nielsen, John; d'Ettorre, Patrizia

    2010-12-22

    The selective forces that shape and maintain eusocial societies are an enduring puzzle in evolutionary biology. Ordinarily sterile workers can usually reproduce given the right conditions, so the factors regulating reproductive division of labour may provide insight into why eusociality has persisted over evolutionary time. Queen-produced pheromones that affect worker reproduction have been implicated in diverse taxa, including ants, termites, wasps and possibly mole rats, but to date have only been definitively identified in the honeybee. Using the black garden ant Lasius niger, we isolate the first sterility-regulating ant queen pheromone. The pheromone is a cuticular hydrocarbon that comprises the majority of the chemical profile of queens and their eggs, and also affects worker behaviour, by reducing aggression towards objects bearing the pheromone. We further show that the pheromone elicits a strong response in worker antennae and that its production by queens is selectively reduced following an immune challenge. These results suggest that the pheromone has a central role in colony organization and support the hypothesis that worker sterility represents altruistic self-restraint in response to an honest quality signal. PMID:20591861

  20. Queen's University Aboriginal Teacher Education Program: An Exercise in Partnership.

    ERIC Educational Resources Information Center

    Hill, Janice C.

    The Aboriginal Teacher Education Program (ATEP) at Queen's University (Ontario) delivers two models of teacher education. One is community-based, part-time, and for Aboriginal students only, who may enter with a secondary school graduation diploma or equivalent. The second is campus-based, full-time, and open to both Aboriginal and non-Aboriginal…

  1. 65. Receiving gold numbers on her designation as "Queen of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    65. Receiving gold numbers on her designation as "Queen of the Fleet," serving as the oldest Coast Guard Cutter in active service when U.S. Coast Guard Cutter Ingham was decommissioned on May 27, 1988. - U.S. Coast Guard Cutter FIR, Puget Sound Area, Seattle, King County, WA

  2. The Imperial Style: Rhetorical Depiction and Queen Victoria's Diamond Jubilee.

    ERIC Educational Resources Information Center

    Andrews, James R.

    2000-01-01

    Contributes to scholarship advancing the understanding of human communication by examining a powerful set of imperialist symbols that have a lingering impact on the British national psyche. Investigates the Queen's Diamond Jubilee speech and the performative rhetoric of the Jubilee celebration itself, to illustrate how rhetorical depiction may…

  3. Cooperation, conflict, and the evolution of queen pheromones.

    PubMed

    Kocher, Sarah D; Grozinger, Christina M

    2011-11-01

    While chemical communication regulates individual behavior in a wide variety of species, these communication systems are most elaborated in insect societies. In these complex systems, pheromones produced by the reproductive individuals (queens) are critical in establishing and maintaining dominant reproductive status over hundreds to thousands of workers. The proximate and ultimate mechanisms by which these intricate pheromone communication systems evolved are largely unknown, though there has been much debate over whether queen pheromones function as a control mechanism or as an honest signal facilitating cooperation. Here, we summarize results from recent studies in honey bees, bumble bees, wasps, ants and termites. We further discuss evolutionary mechanisms by which queen pheromone communication systems may have evolved. Overall, these studies suggest that queen-worker pheromone communication is a multi-component, labile dialog between the castes, rather than a simple, fixed signal-response system. We also discuss future approaches that can shed light on the proximate and ultimate mechanisms that underlie these complex systems by focusing on the development of increasingly sophisticated genomic tools and their potential applications to examine the molecular mechanisms that regulate pheromone production and perception. PMID:22083225

  4. Redemptive Journey: The Storytelling Motif in Andersen's "The Snow Queen."

    ERIC Educational Resources Information Center

    Misheff, Sue

    1989-01-01

    Discusses how Hans Christian Andersen's "The Snow Queen" uses the motif of storytelling to describe the journey taken by the heroine Gerda. Identifies a story as that which is alive and active and which causes catharsis for those who participate in it. (MG)

  5. Queens Tri-School Confederation, 1991-92 Evaluation Report.

    ERIC Educational Resources Information Center

    Hannah, Susan; Dworkowitz, Barbara

    An evaluation was done of the Queens Tri-School Confederation, three high schools in the New York City Public Schools funded by a federal grant from the Magnet Schools Assistance Program. The grant provided Hillcrest, Jamaica, and Thomas A. Edison High Schools with funds to develop or expand emergency technician programs at Hillcrest; a law…

  6. Non-transferable signals on ant queen eggs

    NASA Astrophysics Data System (ADS)

    D'Ettorre, Patrizia; Tofilski, Adam; Heinze, Jürgen; Ratnieks, Francis L. W.

    2006-03-01

    How biological systems resolve internal conflicts is a major evolutionary question. Social insect workers cooperate but also pursue individual interests, such as laying male eggs. The rewards of this individual selfishness can be reduced by policing, such as by killing worker-laid eggs. However, selfish individuals may evade policing. What factors prevent individuals from being able to evade policing? In the ant Pachycondyla inversa, workers kill (police) worker-laid eggs. Because the colony keeps eggs in piles and worker-laid and queen-laid eggs are chemically distinct, worker-laid eggs might become more acceptable once placed in the egg pile by odour transfer from touching queen-laid eggs. Here, we show that such “cue scrambling” does not occur. Worker-laid eggs that were sandwiched between three queen-laid eggs for 45 min were not more acceptable in a policing bioassay than control worker-laid eggs. Chemical analyses also showed that the surface hydrocarbon profile of these eggs was unchanged. Policing, therefore, is stable against this potential cheating mechanism probably because queen-laid eggs are made chemically distinct using chemicals, that are not easily transferred by physical contact.

  7. Nurturer or Queen Bee? Models of Women's Leadership

    ERIC Educational Resources Information Center

    Malveaux, Julianne

    2005-01-01

    This document describes an informal chat of about 30 students, faculty, staff, and administrators, mostly African-American women, with a couple of White and Latina sisters thrown in. One woman asked why African-American women were so mean to each other. The author retreated into a conversation about two models of women's leadership--Queen Bee or…

  8. The Queen's Two Bodies: Sor Juana and New Spain's Vicereines

    ERIC Educational Resources Information Center

    Thomas, George Anthony

    2009-01-01

    The work of Sor Juana Ines de la Cruz contains many examples of positive representations of the Queens of Spain and the Vicereines of New Spain. These poetic portraits serve to counter the primarily misogynistic portrayals of ruling women of the seventeenth century. Most importantly, Sor Juana increased the visibility of the vicereine in colonial…

  9. Artificial diets for juvenile queen conch: Studies examine algae content

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers at Harbor Branch Oceanographic Institute at Florida Atlantic University found juvenile queen conch fed diets containing added macroalgae had higher survival than a control given catfish feed only, but saw no significant difference in overall growth rates among the treatments. In a secon...

  10. 40. GARRET TRUSS DETAIL. The south queen post (called 'king ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. GARRET TRUSS DETAIL. The south queen post (called 'king post' in the 1755 account for scantling for the Greater Meeting House) of the third truss from the east end. Note the numerals for assembling the truss members and the plaster marks from the 1755 Monthly Meeting Room. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

  11. Classical conditioning of proboscis extension in harnessed Africanized honey bee queens (Apis mellifera L.).

    PubMed

    Aquino, Italo S; Abramson, Charles I; Soares, Ademilson E E; Fernandes, Andrea Cardoso; Benbassat, Danny

    2004-06-01

    Experiments are reported on learning in virgin Africanized honey bee queens (Apis mellifera L.). Queens restrained in a "Pavlovian harness" received a pairing of hexanal odor with a 1.8-M feeding of sucrose solution. Compared to explicitly unpaired controls, acquisition was rapid in reaching about 90%. Acquisition was also rapid in queens receiving an unconditioned stimulus of "bee candy" or an unconditioned stimulus administered by worker bees. During extinction the conditioned response declines. The steepest decline was observed in queens receiving an unconditioned stimulus of bee candy. These findings extend previous work on learning of Afrianized honey bee workers to a population of queen bees. PMID:15362396

  12. Chemical communication of queen supergene status in an ant.

    PubMed

    Trible, W; Ross, K G

    2016-03-01

    Traits of interest to evolutionary biologists often have complex genetic architectures, the nature of which can confound traditional experimental study at single levels of analysis. In the fire ant Solenopsis invicta, the presence of a Mendelian 'supergene' is both necessary and sufficient to induce a shift in a fundamental property of social organization, from single-queen (monogyne) to multiple-queen (polygyne) colonies. This selfish genetic element, termed the Social b (Sb) supergene, contains > 600 genes that collectively promote its fitness by inducing the characteristic polygyne syndrome, in part by causing polygyne workers to accept only queens bearing the Sb element (a behaviour termed 'worker Sb discrimination'). Here, we employ a newly developed behavioural assay to reveal that polygyne workers, many of which bear the Sb element, employ chemical cues on the cuticle of queens to achieve worker Sb discrimination, but we found no evidence for such pheromonally mediated worker Sb discrimination in monogyne workers, which universally lack the Sb element. This polygyne worker Sb discrimination was then verified through a 'green beard' effect previously described in this system. We thus have demonstrated that the Sb element is required both for production of relevant chemical cues of queens and for expression of the behaviours of workers that collectively result in worker Sb discrimination. This information fills a critical gap in the map between genotype and complex phenotype in S. invicta by restricting the search for candidate genes and molecules involved in producing this complex social trait to factors associated with the Sb element itself. PMID:26644320

  13. Interaction and behavior of virgin and physogastric queens in three Meliponini species (Hymenoptera, Apidae).

    PubMed

    Nogueira-Ferreira, F H; Silva-Matos, E V; Zucchi, R

    2009-01-01

    We studied the behavior of virgin queens of the stingless bee species Schwarziana quadripunctata, Paratrigona lineata and Tetragona clavipes, investigating internal nest activities, including the cell provisioning and oviposition process. We made direct observation of queen behavior, with the aid of video filming. Forty-four virgin queens of S. quadripunctata were observed; one was larger and more attractive than the others. Miniature queens were more abundant than normal-size queens; both were found in prison chambers. Agonistic behavior between virgin and physogastric queens of P. lineata was observed during attempts at queen supersedure. After the disappearance of the physogastric queen and the appearance of a virgin queen in T. clavipes nests, the brood cells were sealed with pollen alone, but no egg. In all three species, the presence of one or more virgin queens appeared to make the colonies nervous, even though constant production of virgin queens is vital to the survival of the colony and is part of the colony cycle in these bees. PMID:19554769

  14. Does the queen win it all? Queen-worker conflict over male production in the bumblebee, Bombus terrestris

    NASA Astrophysics Data System (ADS)

    Alaux, Cédric; Savarit, Fabrice; Jaisson, Pierre; Hefetz, Abraham

    Social insects provide a useful model for studying the evolutionary balance between cooperation and conflict linked to genetic structure. We investigated the outcome of this conflict in the bumblebee, Bombus terrestris, whose annual colony life cycle is characterized by overt competition over male production. We established artificial colonies composed of a queen and unrelated workers by daily exchange of callow workers between colony pairs of distinct genetic make-up. Using microsatellite analysis, this procedure allowed an exact calculation of the proportion of worker-derived males. The development and social behavior of these artificial colonies were similar to those of normal colonies. Despite a high worker reproduction attempt (63.8% of workers had developed ovaries and 38.4% were egg-layers), we found that on average 95% of the males produced during the competition phase (CPh) were queen-derived. However, in four colonies, queen death resulted in a considerable amount of worker-derived male production. The different putative ultimate causes of this efficient control by the queen are discussed, and we suggest a possible scenario of an evolutionary arms race that may occur between these two female castes.

  15. 75 FR 68397 - DeQueen and Eastern Railroad, LLC-Acquisition and Operation Exemption-DeQueen and Eastern...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-05

    ... border) and milepost 87.0 (Perkins, Ark.), including auxiliary, temporary storage, and spur tracks, in Howard and Sevier Counties, Ark.\\1\\ \\1\\ DQE states that it intends to interchange traffic at De Queen, Ark. with Kansas City Southern Railway Company, at Perkins with Union Pacific Railroad Company, and...

  16. Comparisons of the queen volatile compounds of instrumentally inseminated versus naturally mated honey bee (Apis mellifera) queens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Instrumental insemination is an attractive alternative to natural mating because specific genetic crosses can be made, thus producing colonies with desired traits. However, there are conflicting reports on the quality and acceptance of instrumentally inseminated (II) queens compared to naturally ma...

  17. Octopamine and cooperation: octopamine regulates the disappearance of cooperative behaviours between genetically unrelated founding queens in the ant.

    PubMed

    Koyama, Satoshi; Matsui, Shingo; Satoh, Toshiyuki; Sasaki, Ken

    2015-06-01

    We investigated whether octopamine (OA) is associated with the disappearance of cooperation in Polyrhachis moesta ant queens. Queens of P. moesta facultatively found the colony with genetically unrelated queens. The founding queens perform frequent food exchange with these non-related queens and partake in cooperative brood rearing, whereas single colony queens exclude non-related queens via aggressive behaviour. Thus, aggression is a factor that reduces cooperation. Given that aggression is generally associated with brain OA in insects, we hypothesized that OA controls the behavioural change in cooperation in the ant queen, via an increase in aggression. To test this hypothesis, we compared the amounts of OA and related substances in the brain between founding and colony queens, and observed the interaction of founding queens following oral OA administration. The brain OA levels in colony queens were significantly higher than those in founding queens. Oral administration of OA to founding queens caused significantly less trophallaxis and allogrooming behaviour than in the control founding queens, but with no significant increase in aggression. These results suggest that OA promotes the disappearance of cooperation in founding queens of P. moesta. This is the first study to reveal the neuroendocrine mechanism of cooperation in ant queens. PMID:26085498

  18. Colony failure linked to low sperm viability in honey bee (Apis mellifera) queens and an exploration of potential causative factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Queen health is closely linked to colony performance in honey bees as a single queen is normally responsible for all egg laying and brood production within the colony. In the U. S. in recent years, queens have been failing at a high rate; with 50% or greater of queens replaced in colonies within 6 m...

  19. Strange baryonic resonances and resonances coupling to strange hadrons at SIS energies

    NASA Astrophysics Data System (ADS)

    Fabbietti, L.

    2016-01-01

    The role played by baryonic resonances in the production of final states containing strangeness for proton-proton reactions at 3.5 GeV measured by HADES is discussed by means of several very different measurements. First the associate production of Δ resonances accompanying final states with strange hadrons is presented, then the role of interferences among N* resonances, as measured by HADES for the first time, is summarised. Last but not least the role played by heavy resonances, with a mass larger than 2 GeV/c2 in the production of strange and non-strange hadrons is discussed. Experimental evidence for the presence of a Δ(2000)++ are presented and hypotheses are discussed employing the contribution of similar objects to populate the excesses measured by HADES for the Ξ in A+A and p+A collisions and in the dilepton sector for A+A collisions. This extensive set of results helps to better understand the dynamic underlaying particle production in elementary reactions and sets a more solid basis for the understanding of heavy ion collisions at the same energies and even higher as planned at the FAIR facility.

  20. Queen signals in a stingless bee: suppression of worker ovary activation and spatial distribution of active compounds

    PubMed Central

    Nunes, Túlio M.; Mateus, Sidnei; Favaris, Arodi P.; Amaral, Mônica F. Z. J.; von Zuben, Lucas G.; Clososki, Giuliano C.; Bento, José M. S.; Oldroyd, Benjamin P.; Silva, Ricardo; Zucchi, Ronaldo; Silva, Denise B.; Lopes, Norberto P.

    2014-01-01

    In most species of social insect the queen signals her presence to her workers via pheromones. Worker responses to queen pheromones include retinue formation around the queen, inhibition of queen cell production and suppression of worker ovary activation. Here we show that the queen signal of the Brazilian stingless bee Friesella schrottkyi is a mixture of cuticular hydrocarbons. Stingless bees are therefore similar to ants, wasps and bumble bees, but differ from honey bees in which the queen's signal mostly comprises volatile compounds originating from the mandibular glands. This shows that cuticular hydrocarbons have independently evolved as the queen's signal across multiple taxa, and that the honey bees are exceptional. We also report the distribution of four active queen-signal compounds by Matrix-assisted laser desorption/ionization (MALDI) imaging. The results indicate a relationship between the behavior of workers towards the queen and the likely site of secretion of the queen's pheromones. PMID:25502598

  1. Seismic search for strange quark nuggets

    SciTech Connect

    Herrin, Eugene T.; Rosenbaum, Doris C.; Teplitz, Vigdor L.

    2006-02-15

    Bounds on masses and abundances of Strange Quark Nuggets (SQNs) are inferred from a seismic search on Earth. Potential SQN bounds from a possible seismic search on the Moon are reviewed and compared with Earth capabilities. Bounds are derived from the data taken by seismometers implanted on the Moon by the Apollo astronauts. We show that the Apollo data implies that the abundance of SQNs in the region of 10 kg to 1 ton must be at least an order of magnitude less than would saturate the dark matter in the solar neighborhood.

  2. Strange Quark Matter Status and Prospects

    NASA Technical Reports Server (NTRS)

    Sandweiss, J.

    2004-01-01

    The existence of quark states with more than three quarks is allowed in QCD. The stability of such quark matter states has been studied with lattice QCD and phenomenological bag models, but is not well constrained by theory. The addition of strange quarks to the system allows the quarks to be in lower energy states despite the additional mass penalty. There is additional stability from reduced Coulomb repulsion. SQM is expected to have a low Z/A. Stable or metastable massive multiquark states contain u, d, and s quarks.

  3. HD 207739 - A strange composite star

    NASA Technical Reports Server (NTRS)

    Parsons, S. B.; Holm, A. V.; Kondo, Y.

    1983-01-01

    This star, classified F8 IIe + B:, has a very unusual ultraviolet spectrum, with abnormally strong and numerous absorption features in the far-UV and exceptionally strong Mg II emission. There is some resemblance to shell and pre-main-sequence B stars, but it more closely matches the strange spectra of the eclipsing systems VV Cep and SX Cas, and it probably has considerable circumstellar material at fairly high temperature. HD 207739 is probably an interacting binary and needs to be monitored for light and velocity variations.

  4. Radial oscillations of charged strange stars

    NASA Astrophysics Data System (ADS)

    Arbañil, J. D. V.; Malheiro, M.

    2016-04-01

    The radial oscillations of charged strange quark stars is investigated. It is considered that the fluid pressure follows the MIT bag model equation of state and the charge density to be proportional to the energy density, ρe = αρ (where α is proportionality constant). The modified equations of radial oscillations to the introduction of the electric charge are integrated to determine the fundamental mode. It is found that the stability of the charged object decreases with the increment of the central energy density and with the growth of the charge fraction.

  5. Quark number susceptibilities, strangeness, and dynamical confinement

    NASA Astrophysics Data System (ADS)

    Gavai, Rajiv V.; Gupta, Sourendu

    2001-10-01

    We report the first results on the strange quark number susceptibility χs over a large range of temperatures, mainly in the plasma phase of QCD. χs jumps across the phase transition temperature Tc and grows rapidly with temperature above but close to Tc. For all quark masses and susceptibilities in the entire temperature range studied, we find a significant departure from ideal-gas values. We also observe a strong correlation between these quantities and the susceptibility in the pseudoscalar channel, supporting ideas of ``dynamical confinement'' in the high temperature phase of the QCD plasma.

  6. METHODOLOGICAL NOTES: Strange attractors in rattleback dynamics

    NASA Astrophysics Data System (ADS)

    Borisov, Aleksei V.; Mamaev, Ivan S.

    2003-04-01

    This review is dedicated to the dynamics of the rattleback, a phenomenon with curious physical properties that is studied in nonholonomic mechanics. All known analytical results are collected here, and some results of our numerical simulation are presented. In particular, three-dimensional Poincare maps associated with dynamical systems are systematically investigated for the first time. It is shown that the loss of stability of periodic and quasiperiodic solutions, which gives rise to strange attractors, is typical of the three-dimensional maps related to rattleback dynamics. This explains some newly discovered properties of the rattleback related to the transition from regular to chaotic solutions at certain values of the physical parameters.

  7. Stability of charged strange quark stars

    SciTech Connect

    Arbañil, José D. V.; Malheiro, Manuel

    2015-12-17

    We investigate the hydrostatic equilibrium and the stability of charged stars made of a charged perfect fluid. The matter contained in the star follows the MIT bag model equation of state and the charge distribution to a power-law of the radial coordinate. The hydrostatic equilibrium and the stability of charged strange stars are analyzed using the Tolman-Oppenheimer-Volkoff equation and the Chandrasekhar’s equation pulsation, respectively. These two equation are modified from their original form to the inclusion of the electric charge. We found that the stability of the star decreases with the increment of the central energy density and with the increment of the amount of charge.

  8. A sudden change of a strange repeller

    NASA Astrophysics Data System (ADS)

    Ma, Ming-Quan; Wu, Shunguang; He, Da-Ren

    1998-03-01

    We have observed a transient chaos[1] after a boundary crisis in a simplified model of an impact oscillator. A strange repeller was found there and the scaling of the averaged life time was calculated both analytically and numerically. With the developing of the control parameter, the transient chaos was suddenly destroyed via a collision of a pair of the saddle nodes with a non-differential point of the mapping. The repeller disappeared and the scaling rules significantly changed as well after this collision. [1]:T.Tél, in ``Directions in Chaos'', vol.3, ed. by Hao Bai-lin, World Scientific Pub., Singapore, 1990.

  9. Strangeness of the nucleon from lattice QCD

    NASA Astrophysics Data System (ADS)

    Alexandrou, Constantia; Constantinou, Martha; Dinter, Simon; Drach, Vincent; Hadjiyiannakou, Kyriakos; Jansen, Karl; Koutsou, Giannis; Vaquero, Alejandro; ETM Collaboration

    2015-05-01

    We present a nonperturbative calculation of the strangeness of the nucleon yN within the framework of lattice QCD. This observable is known to be an important cornerstone to interpret results from direct dark matter detection experiments. We perform a lattice computation for yN with an analysis of systematic effects originating from discretization, finite size, chiral extrapolation and excited state effects leading to the value of yN=0.173 (50 ) . The rather large uncertainty of this value of yN is dominated by systematic uncertainties which we are able to quantify in this work.

  10. Strangeness Physics with CLAS at Jefferson Lab

    SciTech Connect

    Schumacher, Reinhard

    2010-08-05

    We review recent developments in strangeness photo- and electro- production off the proton and neutron, as investigated using CLAS in Hall B at Jefferson Lab. By measuring sufficient spin observables one can decompose the reaction mechanism into elementary amplitudes. We discuss progress toward this end in recent data from CLAS, including cross sections and spin observables. We next discuss new results on the mass distribution of the {Lambda}(1405), which shows signs of being a composite meson-baryon object of mixed isospin. The work on other hyperons such as the {Xi} resonances will be mentioned, and future prospects for the CLAS program outlined.

  11. Strangeness Physics with CLAS at Jefferson Lab

    SciTech Connect

    Reinhard Schumacher

    2010-08-01

    We review recent developments in strangeness photo- and electro- production off the proton and neutron, as investigated using CLAS in Hall B at Jefferson Lab. By measuring sufficient spin observables one can decompose the reaction mechanism into elementary amplitudes. We discuss progress toward this end in recent data from CLAS, including cross sections and spin observables. We next discuss new results on the mass distribution of the Lambda(1405), which shows signs of being a composite meson-baryon object of mixed isospin. The work on other hyperons such as the Xi resonances will be mentioned, and future prospects for the CLAS program outlined.

  12. Strangeness at high temperatures: from hadrons to quarks.

    PubMed

    Bazavov, A; Ding, H-T; Hegde, P; Kaczmarek, O; Karsch, F; Laermann, E; Maezawa, Y; Mukherjee, Swagato; Ohno, H; Petreczky, P; Schmidt, C; Sharma, S; Soeldner, W; Wagner, M

    2013-08-23

    Appropriate combinations of up to fourth order cumulants of net strangeness fluctuations and their correlations with net baryon number and electric charge fluctuations, obtained from lattice QCD calculations, have been used to probe the strangeness carrying degrees of freedom at high temperatures. For temperatures up to the chiral crossover, separate contributions of strange mesons and baryons can be well described by an uncorrelated gas of hadrons. Such a description breaks down in the chiral crossover region, suggesting that the deconfinement of strangeness takes place at the chiral crossover. On the other hand, the strangeness carrying degrees of freedom inside the quark gluon plasma can be described by a weakly interacting gas of quarks only for temperatures larger than twice the chiral crossover temperature. In the intermediate temperature window, these observables show considerably richer structures, indicative of the strongly interacting nature of the quark gluon plasma. PMID:24010429

  13. Absence of nepotism in the harassment of duelling queens by honeybee workers.

    PubMed

    Gilley, David C

    2003-10-01

    Nepotism shapes interactions among the members of almost every animal society. However, clear evidence of nepotism within highly cooperative insect societies, such as ant, wasp and honeybee colonies, is rare. Recent empirical findings suggest that nepotism occurs within honeybee colonies where kin-selection theory most strongly predicts its existence: during the lethal queen-queen duels that determine which of several young queens will become the colony's next queen. In this study, I test whether worker bees act nepotistically by hindering duelling queens that are distantly related to themselves. I accomplished this by observing labelled workers harassing duelling queen bees in observation hives and subsequently by determining worker-queen relatedness using DNA microsatellites. I show that the workers that harassed duelling queens were neither more-closely nor more-distantly related to them than were workers selected randomly from the colony. Thus, workers did not behave nepotistically by hindering half-sister queens more than full-sister queens. These results demonstrate that under certain conditions, natural selection limits the evolution of nepotism within animal societies despite strong theoretical predictions for its existence. PMID:14561293

  14. Dilepton and strangeness production probed with HADES

    SciTech Connect

    Rustamov, A.

    2012-05-15

    With the High Acceptance Di-Electron Spectrometer (HADES) at GSI we have studied dilepton production in the few-GeV energy regime in various collisions systems, from elementary NN, over pA, up to the medium-heavy Ar + KCl system. We have thus confirmed the puzzling results of the former DLS Collaboration at the Bevalac. While we have traced the origin of the excess pair yield in CC collisions to elementary pp and pn processes, in our Ar + KCl data a contribution from the dense phase of the collision has been identified. Together with the e{sup +}e{sup -} pairs, we have also obtained in the Ar + KCl system at 1.76 A GeV a high-statistics data set on open and hidden strangeness, i.e. K{sup {+-}}, K{sub s}{sup 0}, {Lambda}, {phi}, and {Xi}{sup -}, allowing for a comprehensive discussion of strangeness production in this system.

  15. Notes on properties of holographic strange metals

    SciTech Connect

    Lee, Bum-Hoon; Pang, Da-Wei

    2010-11-15

    We investigate properties of holographic strange metals in p+2 dimensions, generalizing the analysis performed in [S. A. Hartnoll et al. J. High Energy Phys. 04 (2010) 120]. The bulk spacetime is a p+2-dimensional Lifshitz black hole, while the role of charge carriers is played by probe D-branes. We mainly focus on massless charge carriers, where most of the results can be obtained analytically. We obtain exact results for the free energy and calculate the entropy density and the heat capacity, as well as the speed of sound at low temperature. We obtain the DC conductivity and DC Hall conductivity and find that the DC conductivity takes a universal form in the large density limit, while the Hall conductivity is also universal in all dimensions. We also study the resistivity in different limits and clarify the condition for the linear dependence on the temperature, which is a key feature of strange metals. We show that our results for the DC conductivity are consistent with those obtained via the Kubo formula and we obtain the charge diffusion constant analytically. The corresponding properties of massive charge carriers are also discussed in brief.

  16. Strangeness electroproduction on the nucleon at CLAS

    SciTech Connect

    Daniel Carman

    2012-04-01

    High-precision measurements of strange particle production from both proton and neutron targets are a core part of the physics program with the CLAS spectrometer in Hall B at Jefferson Laboratory. Measurements have been carried out at beam energies up to 6 GeV in experiments with polarized beams and polarized targets. This talk will focus on the electroproduction measurements that have been completed, which include cross sections and hyperon polarization observables for K{sup +}Y (Y = {Lambda}{Sigma}{sup 0}) final states over a broad kinematic range in momentum transfer Q{sup 2} and invariant energy W, while spanning nearly the full kaon center-of-mass angular range. These data in the strangeness sector are necessary to better understand the different production mechanisms for {Lambda} and {Sigma} hyperons and to disentangle the different resonant and non-resonant amplitudes in the intermediate state. The usefulness of the CLAS electroproduction data as part of a coupled-channel model fit will be discussed as well as an outlook of this program for the future.

  17. Notes on properties of holographic strange metals

    NASA Astrophysics Data System (ADS)

    Lee, Bum-Hoon; Pang, Da-Wei

    2010-11-01

    We investigate properties of holographic strange metals in p+2 dimensions, generalizing the analysis performed in [S. A. Hartnoll J. High Energy Phys.JHEPFG1029-8479 04 (2010) 120]. The bulk spacetime is a p+2-dimensional Lifshitz black hole, while the role of charge carriers is played by probe D-branes. We mainly focus on massless charge carriers, where most of the results can be obtained analytically. We obtain exact results for the free energy and calculate the entropy density and the heat capacity, as well as the speed of sound at low temperature. We obtain the DC conductivity and DC Hall conductivity and find that the DC conductivity takes a universal form in the large density limit, while the Hall conductivity is also universal in all dimensions. We also study the resistivity in different limits and clarify the condition for the linear dependence on the temperature, which is a key feature of strange metals. We show that our results for the DC conductivity are consistent with those obtained via the Kubo formula and we obtain the charge diffusion constant analytically. The corresponding properties of massive charge carriers are also discussed in brief.

  18. Strangeness and charm in nuclear matter

    NASA Astrophysics Data System (ADS)

    Tolos, Laura; Cabrera, Daniel; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis

    2013-09-01

    The properties of strange (K, Kbar and K) and open-charm (D, Dbar and D*) mesons in dense matter are studied using a unitary approach in coupled channels for meson-baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden gauge Lagrangians. For the interaction of charmed mesons with nucleons we extend the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects and meson self-energies. On one hand, we obtain the K, Kbar and K spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also make an estimate of the transparency ratio of the γA→K+KA‧ reaction, which we propose as a tool to detect in-medium modifications of the K meson. On the other hand, in the charm sector, several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. The properties of these states in matter are analyzed and their influence on the open-charm meson spectral functions is studied. We finally discuss the possible formation of D-mesic nuclei at FAIR energies.

  19. Questionnaire-based survey of parturition in the queen.

    PubMed

    Musters, J; de Gier, J; Kooistra, H S; Okkens, A C

    2011-06-01

    The lack of scientific data concerning whether parturition in the queen proceeds normally or not may prevent veterinarians and cat owners from recognizing parturition problems in time. A questionnaire-based study of parturition in 197 queens was performed to determine several parameters of parturition and their influence on its progress. The mean length of gestation was 65.3 days (range 57 to 72 days) and it decreased with increasing litter size (P = 0.02). The median litter size was 4.5 kittens (range 1 to 9), with more males (53%) than females (46%) (P = 0.05). Sixty-nine percent of the kittens were born in anterior presentation and 31% in posterior presentation, indicating that either can be considered normal in the cat. Males were born in posterior position (34%) more often than females (26%) (P = 0.03). The mean birth weight was 98 g (range of 35 to 167 g) and decreased with increasing litter size (P < 0.01). Mean birth weight was higher in males and kittens born in posterior presentation (P < 0.01). Forty-four (5%) of the 887 kittens were stillborn. This was not correlated with the presentation at expulsion but stillborn kittens were more often female (P = 0.02) and weighed less than those born alive (P = 0.04). The median interkitten time was 30 min (range 2 to 343 min) and 95% were born within 100 min after expulsion of the preceding kitten. The interkitten time as a measure of the progress of parturition was not influenced by the kitten's gender, presentation at expulsion, birth weight, or stillbirth, or by the parity of the queen. The results of this study can be used to develop reference values for parturition parameters in the queen, both to determine whether a given parturition is abnormal and as the basis for a parturition protocol. PMID:21295830

  20. 39. GARRET TRUSS DETAIL. Connection of a queen post (called ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. GARRET TRUSS DETAIL. Connection of a queen post (called 'king post' in the 1755 account for scantling for the Greater Meeting House) and the bottom chord at the south side of the second truss from the east end. Note the rose head nails and plaster stains from the walls of the 1755 Monthly Meeting Room. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

  1. Asexual queen succession in the subterranean termite Reticulitermes virginicus

    PubMed Central

    Vargo, Edward L.; Labadie, Paul E.; Matsuura, Kenji

    2012-01-01

    Termite colonies are founded by a pair of primary reproductives. In many species, including subterranean termites (family Rhinotermitidae), the primary king and queen can be succeeded by neotenic reproductives that are produced from workers or nymphs within the colony. It is generally believed that these neotenics inbreed within the colony, sometimes for many generations. Here, we show that primary queens of the North American subterranean termite, Reticulitermes virginicus, are replaced by numerous parthenogenetically produced female neotenics. We collected functional female neotenics from five colonies of R. virginicus in North Carolina and Texas, USA. Genetic analysis at eight microsatellite loci showed that 91–100% of the neotenics present within a colony were homozygous at all loci, indicating that they were produced through automictic parthenogenesis with terminal fusion. In contrast, workers, soldiers and alates were almost exclusively sexually produced by mating between the female neotenics and a single king. This is the second termite species shown to undergo asexual queen succession, a system first described in the Japanese species, Reticulitermes speratus. Thus, the conditional use of sexual and asexual reproduction to produce members of different castes may be widespread within Reticulitermes and possibly other subterranean termites. PMID:21831899

  2. Strange Stars : An interesting member of the compact object family

    SciTech Connect

    Bagchi, Manjari; Ray, Subharthi; Dey, Jishnu; Dey, Mira

    2008-01-10

    We have studied strange star properties both at zero temperature and at finite temperatures and searched signatures of strange stars in gamma-ray, x-ray and radio astronomy. We have a set of Equations of State (EoS) for strange quark matter (SQM) and solving the TOV equations, we get the structure of strange stars. The maximum mass for a strange star decreases with the increase of temperature, because at high temperatures, the EoS become softer. One important aspect of strange star is that, surface tension depends on the size and structure of the star and is significantly larger than the conventional values. Moment of inertia is another important parameter for compact stars as by comparing theoretical values with observed estimate, it is possible to constrain the dense matter Equation of State. We hope that this approach will help us to decide whether the members of the double pulsar system PSR J0737-3039 are neutron stars or strange stars.

  3. Production of strange clusters in relativistic heavy ion collisions

    SciTech Connect

    Dover, C.B.; Baltz, A.J.; Pang, Yang; Schlagel, T.J.; Kahana, S.H.

    1993-02-01

    We address a number of issues related to the production of strangeness in high energy heavy ion collisions, including the possibility that stable states of multi-strange hyperonic or quark matter might exist, and the prospects that such objects may be created and detected in the laboratory. We make use of events generated by the cascade code ARC to estimate the rapidity distribution dN/dy of strange clusters produced in Si+Au and Au+Au collisions at AGS energies. These calculations are performed in a simple coalescence model, which yields a consistent description of the strange cluster (d, [sup 3]HE, [sup 3]H, [sup 4]He) production at these energies. If a doubly strange, weakly bound [Lambda][Lambda] dibaryon exists, we find that it is produced rather copiously in Au+Au collisions, with dN/dy [approximately]0.1 at raid-rapidity. If one adds another non-strange or strange baryon to a cluster, the production rate decreases by roughly one or two orders of magnitude, respectively. For instance, we predict that the hypernucleus [sub [Lambda][Lambda

  4. Reclaiming the crown: queen to worker conflict over reproduction in Aphaenogaster cockerelli

    NASA Astrophysics Data System (ADS)

    Smith, Adrian A.; Hölldobler, Bert; Liebig, Jürgen

    2011-03-01

    In many social taxa, reproductively dominant individuals sometimes use aggression to secure and maintain reproductive status. In the social insects, queen aggression towards subordinate individuals or workers has been documented and is predicted to occur only in species with a small colony size and a low level of queen-worker dimorphism. We report queen aggression towards reproductive workers in the ant species Aphaenogaster cockerelli, a species with a relatively large colony size and a high level of reproductive dimorphism. Through analysis of cuticular hydrocarbon profiles, we show that queens are aggressive only to reproductively active workers. Non-reproductive workers treated with a hydrocarbon typical for reproductives are attacked by workers but not by queens, which suggests different ways of recognition. We provide possible explanations of why queen aggression is observed in this species.

  5. Depression of brain dopamine and its metabolite after mating in European honeybee (Apis mellifera) queens

    NASA Astrophysics Data System (ADS)

    Harano, Ken-Ichi; Sasaki, Ken; Nagao, Takashi

    2005-07-01

    To explore neuro-endocrinal changes in the brain of European honeybee (Apis mellifera) queens before and after mating, we measured the amount of several biogenic amines, including dopamine and its metabolite in the brain of 6- and 12-day-old virgins and 12-day-old mated queens. Twelve-day-old mated queens showed significantly lower amounts of dopamine and its metabolite (N-acetyldopamine) than both 6- and 12-day-old virgin queens, whereas significant differences in the amounts of these amines were not detected between 6- and 12-day-old virgin queens. These results are explained by down-regulation of both synthesis and secretion of brain dopamine after mating. It is speculated that higher amounts of brain dopamine in virgin queens might be involved in activation of ovarian follicles arrested in previtellogenic stages, as well as regulation of their characteristic behaviors.

  6. Chemical profiles, division of labor and social status in Pachycondyla queens (Hymenoptera: Formicidae)

    NASA Astrophysics Data System (ADS)

    Tentschert, J.; Kolmer, K.; Hölldobler, B.; Bestmann, H.-J.; Delabie, J. H. C.; Heinze, J.

    2001-03-01

    Queens of the neotropical ponerine ant Pachycondyla cf. 'inversa' may co-operate during colony founding. One of several co-founding queens specializes in foraging, whereas the others remain in the nest and guard the brood. Division of labor is achieved by aggressive interactions, which result in the formation of dominance hierarchies. Gas chromatography and mass spectrometry of cuticular hydrocarbons obtained from live queens by SPME revealed consistent differences between the patterns of cuticular hydrocarbons of queens with high versus low rank: only high-ranking queens showed considerable amounts of cuticular pentadecane (n-C15) and heptadecene (n-C17:1). These two substances presumably originate from the queens' Dufour glands.

  7. A parallel algorithm for solving the n-queens problem based on inspired computational model.

    PubMed

    Wang, Zhaocai; Huang, Dongmei; Tan, Jian; Liu, Taigang; Zhao, Kai; Li, Lei

    2015-05-01

    DNA computing provides a promising method to solve the computationally intractable problems. The n-queens problem is a well-known NP-hard problem, which arranges n queens on an n × n board in different rows, columns and diagonals in order to avoid queens attack each other. In this paper, we present a novel parallel DNA algorithm for solving the n-queens problem using DNA molecular operations based on a biologically inspired computational model. For the n-queens problem, we reasonably design flexible length DNA strands representing elements of the allocation matrix, take appropriate biologic manipulations and get the solutions of the n-queens problem in proper length and O(n(2)) time complexity. We extend the application of DNA molecular operations, simultaneity simplify the complexity of the computation and simulate to verify the feasibility of the DNA algorithm. PMID:25817410

  8. Production of strange clusters in relativistic heavy ion collisions

    SciTech Connect

    Dover, C.B.; Baltz, A.J.; Pang, Yang; Schlagel, T.J.; Kahana, S.H.

    1993-02-01

    We address a number of issues related to the production of strangeness in high energy heavy ion collisions, including the possibility that stable states of multi-strange hyperonic or quark matter might exist, and the prospects that such objects may be created and detected in the laboratory. We make use of events generated by the cascade code ARC to estimate the rapidity distribution dN/dy of strange clusters produced in Si+Au and Au+Au collisions at AGS energies. These calculations are performed in a simple coalescence model, which yields a consistent description of the strange cluster (d, {sup 3}HE, {sup 3}H, {sup 4}He) production at these energies. If a doubly strange, weakly bound {Lambda}{Lambda} dibaryon exists, we find that it is produced rather copiously in Au+Au collisions, with dN/dy {approximately}0.1 at raid-rapidity. If one adds another non-strange or strange baryon to a cluster, the production rate decreases by roughly one or two orders of magnitude, respectively. For instance, we predict that the hypernucleus {sub {Lambda}{Lambda}}{sup 6}He should have dN/dy {approximately}5 {times} 10{sup {minus}6} for Au+Au central collisions. It should be possible to measure the successive {Lambda} {yields} p{pi}{minus} weak decays of this object. We comment on the possibility that conventional multi-strange hypernuclei may serve as ``doorway states`` for the production of stable configurations of strange quark matter, if such states exist.

  9. Pheromonal Control of Dealation and Oogenesis in Virgin Queen Fire Ants

    NASA Astrophysics Data System (ADS)

    Fletcher, David J. C.; Blum, Murray S.

    1981-04-01

    In the fire ant Solenopsis invicta, sexually mature virgin females are prevented from shedding their wings and becoming functional egg layers by the presence of the mated queen. Experimental data suggest that this inhibitory effect results from the action of a relatively nonvolatile primer pheromone (or pheromones) produced by the mated queen and distributed by the workers. Target ants are both virgin queens and workers.

  10. Avoid mistakes when choosing a new home: Nest choice and adoption of Leptothorax ant queens.

    PubMed

    Bernadou, Abel; Ruther, Joachim; Heinze, Jürgen

    2015-08-01

    In ants, mating and colony founding are critical steps in the life of ant queens. Outside of their nests, young queens are exposed to intense predation. Therefore, they are expected to have evolved behavior to accurately and quickly locate a nesting place. However, data on the early life history of female reproductives are still lacking. Leptothorax gredleri is a suitable model organism to study the behavior of young queens. Reproductives can be reared under artificial conditions and readily mate in the laboratory. After mating, L. gredleri queens have the options to found solitarily, seek adoption into another colony, or return into their natal nest. In this study, we investigated the decision-making processes of female sexuals before and after mating. In particular, we tested whether female sexuals use chemical cues to find their way back to the nest, studied if they prefer their own nest over other nesting sites and followed the adoption dynamics of mated queens over 8 weeks (plus hibernation and spring). We showed that female sexuals and freshly mated queens spent more time on substrate previously used by workers from their own colony and from another colony than on a blank substrate. This discriminatory capability of queens appears to be lost in old, reproductive queens. Nest choice experiments showed that female sexuals and freshly mated queens can distinguish their own nest while old mated queens do not. When reintroduced in their maternal colony, young queens were readily adopted, but a few weeks later aggression against young queens led to their emigration from the maternal nest and eventually also death. PMID:26086676

  11. STAR results on strangeness production in beam energy scan program

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoping

    2016-01-01

    We present the recent STAR results on the production of strange hadrons (K0s, ϕ, Λ, Ξ and Ω) in √sNN= 7.7 — 39 GeV Au+Au collisions in the RHIC beam energy scan program. We investigate the strangeness enhancement and strangeness equilibration as a function of beam energy and system size at RHIC. Nuclear modification factors and particle ratios will be highlighted. Implications on partonic vs. hadronic dynamics as a function of the beam energy will be discussed.

  12. Thelytokous parthenogenesis by queens in the dacetine ant Pyramica membranifera (Hymenoptera: Formicidae)

    NASA Astrophysics Data System (ADS)

    Ito, Fuminori; Touyama, Yoshifumi; Gotoh, Ayako; Kitahiro, Shungo; Billen, Johan

    2010-08-01

    Thelytokous parthenogenesis in which diploid females are produced from unfertilized eggs, was recently reported for some ant species. Here, we document thelytokous reproduction by queens in the polygynous species Pyramica membranifera. Queens that emerged in the laboratory were kept with or without workers under laboratory conditions. Independent colony founding was successful for a few queens if prey was provided. All artificial colonies, which started with a newly emerged queen and workers produced new workers and some of the colonies also produced female sexuals. Some of the female sexuals shed their wings in the laboratory and started formation of new polygynous colonies. Workers had no ovaries and thus, were obligatorily sterile.

  13. Queen-specific volatile in a higher termite Nasutitermes takasagoensis (Isoptera: Termitidae).

    PubMed

    Himuro, Chihiro; Yokoi, Tomoyuki; Matsuura, Kenji

    2011-07-01

    In social insect colonies, queen-produced pheromones have important functions in social regulation. These substances influence the behavior and physiology of colony members. A queen-produced volatile that inhibits differentiation of new neotenic reproductives was recently identified in the lower termite Reticulitermes speratus. However, there are no known queen-specific volatiles of this type in any other termite species. Here, we report volatile compounds emitted by live queens of the higher termite Nasutitermes takasagoensis. We used headspace gas chromatography mass spectroscopy (HS GC-MS) to analyze volatiles emitted by live primary queens, workers, soldiers, alates, and eggs collected in a Japanese subtropical forest. Among 14 detected compounds, 7 were soldier-specific, 1 was alate-specific, 1 was egg-specific, and 1 was queen-specific. The queen-specific volatile was phenylethanol, which is different than the compound identified in R. speratus. The identification of this queen-specific volatile is the first step in determining its functions in higher termite social regulation. Comparisons of queen pheromone substances regulating caste differentiation among various termite taxa will contribute to a better understanding of the evolution of social systems in termites. PMID:21540033

  14. Gene expression and variation in social aggression by queens of the harvester ant Pogonomyrmex californicus.

    PubMed

    Helmkampf, Martin; Mikheyev, Alexander S; Kang, Yun; Fewell, Jennifer; Gadau, Jürgen

    2016-08-01

    A key requirement for social cooperation is the mitigation and/or social regulation of aggression towards other group members. Populations of the harvester ant Pogonomyrmex californicus show the alternate social phenotypes of queens founding nests alone (haplometrosis) or in groups of unrelated yet cooperative individuals (pleometrosis). Pleometrotic queens display an associated reduction in aggression. To understand the proximate drivers behind this variation, we placed foundresses of the two populations into social environments with queens from the same or the alternate population, and measured their behaviour and head gene expression profiles. A proportion of queens from both populations behaved aggressively, but haplometrotic queens were significantly more likely to perform aggressive acts, and conflict escalated more frequently in pairs of haplometrotic queens. Whole-head RNA sequencing revealed variation in gene expression patterns, with the two populations showing moderate differentiation in overall transcriptional profile, suggesting that genetic differences underlie the two founding strategies. The largest detected difference, however, was associated with aggression, regardless of queen founding type. Several modules of coregulated genes, involved in metabolism, immune system and neuronal function, were found to be upregulated in highly aggressive queens. Conversely, nonaggressive queens exhibited a striking pattern of upregulation in chemosensory genes. Our results highlight that the social phenotypes of cooperative vs. solitary nest founding tap into a set of gene regulatory networks that seem to govern aggression level. We also present a number of highly connected hub genes associated with aggression, providing opportunity to further study the genetic underpinnings of social conflict and tolerance. PMID:27178446

  15. 78 FR 77772 - Culturally Significant Objects Imported for Exhibition Determinations: “A Royal Passion: Queen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ... Photography'' SUMMARY: Notice is hereby given of the following determinations: Pursuant to the authority... ``A Royal Passion: Queen Victoria and Photography,'' imported from abroad for temporary...

  16. The Strange Quark Polarisation from COMPASS data

    SciTech Connect

    Kouznetsov, O.

    2009-12-17

    The strange quark helicity distribution {delta}s(x) was derived at LO from the inclusive asymmetry A{sub a,d} and the semi-inclusive asymmetries A{sub 1,d}{sup {pi}}{sup +}, A{sub 1,d}{sup {pi}}{sup -}, A{sub 1,d}{sup K+}, A{sub 1,d}{sup K-}, measured by COMPASS in polarised deep inelastic muon-deuteron scattering. The distribution of {delta}s(x) is compatible with zero in the whole measured range. The value of the first moment of {delta}s and its error are very sensitive to the assumed value of the ratio of the s-bar-quark to u-quark fragmentation functions into positive kaons {integral}D(K+/s)(z)dz/{integral}D{sub u}{sup K+}(z)dz.

  17. The Universe is a Strange Place

    NASA Astrophysics Data System (ADS)

    Wilczek, Frank

    2006-01-01

    Our understanding of ordinary matter is remarkably accurate and complete, but it is based on principles that are very strange and unfamiliar. As I'll explain, we've come to understand matter to be a Music of the Void, in a remarkably literal sense. Just as we physicists finalized that wonderful understanding, towards the end of the twentieth century, astronomers gave us back our humility, by informing us that ordinary matter - what we, and chemists and biologists, and astronomers themselves, have been studying all these centuries constitutes only about 5% of the mass of the universe as a whole. I'll describe some of our promising attempts to rise to this challenge by improving, rather than merely complicating, our description of the world.

  18. The Universe is a Strange Place

    NASA Astrophysics Data System (ADS)

    Wilczek, Frank

    Our understanding of ordinary matter is remarkably accurate and complete, but it is based on principles that are very strange and unfamiliar. As I'll explain, we've come to understand matter to be a Music of the Void, in a remarkably literal sense. Just as we physicists finalized that wonderful understanding, towards the end of the twentieth century, astronomers gave us back our humility, by informing us that ordinary matter - what we, and chemists and biologists, and astronomers themselves, have been studying all these centuries constitutes only about 5% of the mass of the universe as a whole. I'll describe some of our promising attempts to rise to this challenge by improving, rather than merely complicating, our description of the world.

  19. Role of nucleon strangeness in supernova explosions

    NASA Astrophysics Data System (ADS)

    Hobbs, T. J.; Alberg, Mary; Miller, Gerald A.

    2016-05-01

    Recent hydrodynamical simulations of core-collapse supernova (CCSN) evolution have highlighted the importance of thorough control over the microscopic physics responsible for such internal processes as neutrino heating. In particular, it has been suggested that modifications to the neutrino-nucleon elastic cross section can potentially play a crucial role in producing successful CCSN explosions. One possible source of such corrections can be found in a nonzero value for the nucleon's strange helicity content Δ s . In the present analysis, however, we show that theoretical and experimental progress over the past decade has suggested a comparatively small magnitude for Δ s , such that its sole effect is not sufficient to provide the physics leading to CCSN explosions.

  20. Properties of color-flavor locked strange quark matter and strange stars in a new quark mass scaling

    NASA Astrophysics Data System (ADS)

    Chang, Qian; Chen, ShiWu; Peng, GuangXiong; Xu, JianFeng

    2013-09-01

    Considering the effect of one-gluon-exchange interaction between quarks, the color-flavor locked strange quark matter and strange stars are investigated in a new quark mass density-dependent model. It is found that the color-flavor locked strange quark matter can be more stable if the one-gluon-exchange effect is included. The lower density behavior of the sound velocity in this model is different from the previous results. Moreover, the new equation of state leads to a heavier acceptable maximum mass, supporting the recent observation of a compact star mass as large as about 2 times the solar mass.

  1. PREFACE: Strangeness in Quark Matter (SQM2009) Strangeness in Quark Matter (SQM2009)

    NASA Astrophysics Data System (ADS)

    Fraga, Eduardo; Kodama, Takeshi; Padula, Sandra; Takahashi, Jun

    2010-09-01

    The 14th International Conference on Strangeness in Quark Matter (SQM2009) was held in Brazil from 27 September to 2 October 2009 at Hotel Atlântico, Búzios, Rio de Janeiro. The conference was jointly organized by Universidade Federal do Rio de Janeiro, Universidade Estadual de Campinas, Centro Brasileiro de Pesquisas Físicas, Universidade de São Paulo, Universidade Estadual Paulista and Universidade Federal do Rio Grande do Sul. Over 120 scientists from Argentina, Brazil, China, France, Germany, Hungary, Italy, Japan, Mexico, The Netherlands, Norway, Poland, Russia, Slovakia, South Africa, Switzerland, the UK and the USA gathered at the meeting to discuss the physics of hot and dense matter through the signals of strangeness and also the behavior of heavy quarks. Group photograph The topics covered were strange and heavy quark production in nuclear collisions, strange and heavy quark production in elementary processes, bulk matter phenomena associated with strange and heavy quarks, and strangeness in astrophysics. In view of the LHC era and many other upcoming new machines, together with recent theoretical developments, sessions focused on `New developments and new facilities' and 'Open questions' were also included. A stimulating round-table discussion on 'Physics opportunities in the next decade in the view of strangeness and heavy flavor in matter' was chaired in a relaxed atmosphere by Grazyna Odyniec and conducted by P Braun-Munzinger, W Florkowski, K Redlich, K Šafařík and H Stöcker, We thank these colleagues for pointing out to young participants new physics directions to be pursued. We also thank J Dunlop and K Redlich for excellent introductory lectures given on the Sunday evening pre-conference session. In spite of the not-so-helpful weather, the beauty and charm of the town of Búzios helped to make the meeting successful. Nevertheless, the most important contributions were the excellent talks, whose contents are part of these proceedings, given

  2. K meson-nucleus interactions: strangeness and nuclear matter

    SciTech Connect

    Kahana, S.

    1985-01-01

    A brief review is provided of some straightforward K-nuclear and ..lambda..-hypernuclear systems. A discussion of less straightforward speculations on H-dibaryons and strange quark matter by many authors, is also given. 28 refs., 6 figs.

  3. Exploring strange nucleon form factors on the lattice

    NASA Astrophysics Data System (ADS)

    Babich, Ronald; Brower, Richard C.; Clark, Michael A.; Fleming, George T.; Osborn, James C.; Rebbi, Claudio; Schaich, David

    2012-03-01

    We discuss techniques for evaluating sea quark contributions to hadronic form factors on the lattice and apply these to an exploratory calculation of the strange electromagnetic, axial, and scalar form factors of the nucleon. We employ the Wilson gauge and fermion actions on an anisotropic 243×64 lattice, probing a range of momentum transfer with Q2<1GeV2. The strange electric and magnetic form factors, GEs(Q2) and GMs(Q2), are found to be small and consistent with zero within the statistics of our calculation. The lattice data favor a small negative value for the strange axial form factor GAs(Q2) and exhibit a strong signal for the bare strange scalar matrix element ⟨N|s¯s|N⟩0. We discuss the unique systematic uncertainties affecting the latter quantity relative to the continuum, as well as prospects for improving future determinations with Wilson-like fermions.

  4. Possible resolution of the strange quark polarization puzzle?

    NASA Astrophysics Data System (ADS)

    Leader, Elliot; Sidorov, Alexander V.; Stamenov, Dimiter B.

    2011-07-01

    The strange quark polarization puzzle, i.e. the contradiction between the negative polarized strange quark density obtained from analyses of inclusive deep inelastic scattering data and the positive values obtained from combined analyses of inclusive and semi-inclusive deep inelastic scattering data using de Florian, Sassot, Stratmann fragmentation functions, is discussed. To this end the results of a new combined next-to-leading order QCD analysis of the polarized inclusive and semi-inclusive deep inelastic scattering data, using the Hirai, Kumano, Nagai, Sudoh (HKNS) fragmentation functions, are presented. It is demonstrated that the polarized strange quark density is very sensitive to the kaon fragmentation functions, and if the set of HKNS fragmentation functions is used, the polarized strange quark density obtained from the combined analysis turns out to be negative and well consistent with values obtained from the pure deep inelastic scattering analyses.

  5. Mass Ejection by Strange Star Mergers and Observational Implications

    SciTech Connect

    Bauswein, A.; Janka, H.-T.; Oechslin, R.; Pagliara, G.; Schaffner-Bielich, J.; Sagert, I.; Hohle, M. M.; Neuhaeuser, R.

    2009-07-03

    We determine the Galactic production rate of strangelets as a canonical input to calculations of the measurable cosmic ray flux of strangelets by performing simulations of strange star mergers and combining the results with recent estimates of stellar binary populations. We find that the flux depends sensitively on the bag constant of the MIT bag model of QCD and disappears for high values of the bag constant and thus more compact strange stars. In the latter case, strange stars could coexist with ordinary neutron stars as they are not converted by the capture of cosmic ray strangelets. An unambiguous detection of an ordinary neutron star would then not rule out the strange matter hypothesis.

  6. Mass ejection by strange star mergers and observational implications.

    PubMed

    Bauswein, A; Janka, H-T; Oechslin, R; Pagliara, G; Sagert, I; Schaffner-Bielich, J; Hohle, M M; Neuhäuser, R

    2009-07-01

    We determine the Galactic production rate of strangelets as a canonical input to calculations of the measurable cosmic ray flux of strangelets by performing simulations of strange star mergers and combining the results with recent estimates of stellar binary populations. We find that the flux depends sensitively on the bag constant of the MIT bag model of QCD and disappears for high values of the bag constant and thus more compact strange stars. In the latter case, strange stars could coexist with ordinary neutron stars as they are not converted by the capture of cosmic ray strangelets. An unambiguous detection of an ordinary neutron star would then not rule out the strange matter hypothesis. PMID:19659133

  7. Nucleation of strange matter in dense stellar cores

    SciTech Connect

    Horvath, J.E. Sao Paulo, Sao Paulo ); Benvenuto, O.G. La Plata ); Vucetich, H. La Plata )

    1992-05-15

    We investigate the nucleation of strange quark matter inside hot, dense nuclear matter. Applying Zel'dovich's kinetic theory of nucleation we find a lower limit of the temperature {ital T} for strange-matter bubbles to appear, which happens to be satisfied inside the Kelvin-Helmholtz cooling era of a compact star life but not much after it. Our bounds thus suggest that a prompt conversion could be achieved, giving support to earlier expectations for nonstandard type-II supernova scenarios.

  8. Higher dimensional strange quark matter solutions in self creation cosmology

    NASA Astrophysics Data System (ADS)

    Şen, R.; Aygün, S.

    2016-03-01

    In this study, we have generalized the higher dimensional flat Friedmann-Robertson-Walker (FRW) universe solutions for a cloud of string with perfect fluid attached strange quark matter (SQM) in Self Creation Cosmology (SCC). We have obtained that the cloud of string with perfect fluid does not survive and the string tension density vanishes for this model. However, we get dark energy model for strange quark matter with positive density and negative pressure in self creation cosmology.

  9. Overview of Issues Surrounding Strangeness in the Nucleon

    SciTech Connect

    A. W. Thomas

    2009-12-01

    The calculation of the strangeness content of the nucleon and its experimental verification is a fundamental step in establishing non-perturbative QCD as the correct theory describing the structure of hadrons. It holds a role in QCD analogous to the correct calculation of the Lamb shift in QED. We review the latest developments in the vector and scalar matrix elements of the strange quarks in the proton, where there has recently been considerable progress.

  10. Hadron spectroscopy from strangeness to charm and beauty

    NASA Astrophysics Data System (ADS)

    Zou, B. S.

    2013-09-01

    Quarks of different flavors have different masses, which will cause breaking of flavor symmetries of QCD. Flavor symmetries and their breaking in hadron spectroscopy play important role for understanding the internal structures of hadrons. Hadron spectroscopy with strangeness reveals the importance of unquenched quark dynamics. Systematic study of hadron spectroscopy with strange, charm and beauty quarks would be very revealing and essential for understanding the internal structure of hadrons and its underlying quark dynamics.