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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. 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.

  3. Red Queen Dynamics with Non-Standard Fitness Interactions

    PubMed Central

    Engelstädter, Jan; Bonhoeffer, Sebastian

    2009-01-01

    Antagonistic coevolution between hosts and parasites can involve rapid fluctuations of genotype frequencies that are known as Red Queen dynamics. Under such dynamics, recombination in the hosts may be advantageous because genetic shuffling can quickly produce disproportionately fit offspring (the Red Queen hypothesis). Previous models investigating these dynamics have assumed rather simple models of genetic interactions between hosts and parasites. Here, we assess the robustness of earlier theoretical predictions about the Red Queen with respect to the underlying host-parasite interactions. To this end, we created large numbers of random interaction matrices, analysed the resulting dynamics through simulation, and ascertained whether recombination was favoured or disfavoured. We observed Red Queen dynamics in many of our simulations provided the interaction matrices exhibited sufficient ‘antagonicity’. In agreement with previous studies, strong selection on either hosts or parasites favours selection for increased recombination. However, fast changes in the sign of linkage disequilibrium or epistasis were only infrequently observed and do not appear to be a necessary condition for the Red Queen hypothesis to work. Indeed, recombination was often favoured even though the linkage disequilibrium remained of constant sign throughout the simulations. We conclude that Red Queen-type dynamics involving persistent fluctuations in host and parasite genotype frequencies appear to not be an artefact of specific assumptions about host-parasite fitness interactions, but emerge readily with the general interactions studied here. Our results also indicate that although recombination is often favoured, some of the factors previously thought to be important in this process such as linkage disequilibrium fluctuations need to be reassessed when fitness interactions between hosts and parasites are complex. PMID:19680432

  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. 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…

  6. The shift between the Red Queen and the Red King effects in mutualisms.

    PubMed

    Gao, Lei; Li, Yao-Tang; Wang, Rui-Wu

    2015-02-04

    Interspecific mutualisms consist of partners trading services that yield common benefits to both species. Until now, understanding how the payoffs from mutualistic cooperation are allocated among the participants has been problematic. Two hypotheses have been proposed to resolve this problem. The Red Queen effect argues that faster-evolving species are favoured in co-evolutionary processes because they are able to obtain a larger share of benefits. Conversely, the Red King effect argues that the slower-evolving species gains a larger share of benefits. The model we propose shows that the allocations for a common benefit vary when the effect of a reward mechanism is included in the model. The outcome is a shift from the Red Queen effect to the Red King effect and vice versa. In addition, our model shows that either an asymmetry in payoff or an asymmetry in the number of cooperative partners causes a shift between the Red Queen effect and the Red King effect. Even in situations where the evolutionary rates are equal between the two species, asymmetries in rewards and in participant number lead to an uneven allocation of benefits among the partners.

  7. How the Red Queen drives terrestrial mammals to extinction.

    PubMed

    Quental, Tiago B; Marshall, Charles R

    2013-07-19

    Most species disappear by the processes of background extinction, yet those processes are poorly understood. We analyzed the evolutionary dynamics of 19 Cenozoic terrestrial mammalian clades with rich fossil records that are now fully extinct or in diversity decline. We find their diversity loss was not just a consequence of "gamblers ruin" but resulted from the evolutionary loss to the Red Queen, a failure to keep pace with a deteriorating environment. Diversity loss is driven equally by both depressed origination rates and elevated extinction rates. Although we find diversity-dependent origination and extinction rates, the diversity of each clade only transiently equaled the implied equilibrium diversity. Thus, the processes that drove diversity loss in terrestrial mammal clades were fundamentally nonequilibrial and overwhelmed diversity-dependent processes.

  8. The Red Queen and King in finite populations.

    PubMed

    Veller, Carl; Hayward, Laura K; Hilbe, Christian; Nowak, Martin A

    2017-07-03

    In antagonistic symbioses, such as host-parasite interactions, one population's success is the other's loss. In mutualistic symbioses, such as division of labor, both parties can gain, but they might have different preferences over the possible mutualistic arrangements. The rates of evolution of the two populations in a symbiosis are important determinants of which population will be more successful: Faster evolution is thought to be favored in antagonistic symbioses (the "Red Queen effect"), but disfavored in certain mutualistic symbioses (the "Red King effect"). However, it remains unclear which biological parameters drive these effects. Here, we analyze the effects of the various determinants of evolutionary rate: generation time, mutation rate, population size, and the intensity of natural selection. Our main results hold for the case where mutation is infrequent. Slower evolution causes a long-term advantage in an important class of mutualistic interactions. Surprisingly, less intense selection is the strongest driver of this Red King effect, whereas relative mutation rates and generation times have little effect. In antagonistic interactions, faster evolution by any means is beneficial. Our results provide insight into the demographic evolution of symbionts.

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

    PubMed

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

    2015-04-22

    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.

  10. 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

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

    PubMed

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

    2014-12-22

    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.

  12. 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

  13. 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.

  14. 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

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

    PubMed

    Nordbotten, Jan Martin; Stenseth, Nils C

    2016-02-16

    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.

  16. A phylogenetic test of the Red Queen Hypothesis: outcrossing and parasitism in the Nematode phylum.

    PubMed

    Gibson, Amanda Kyle; Fuentes, Jesualdo Arturo

    2015-02-01

    Sexual outcrossing is costly relative to selfing and asexuality, yet it is ubiquitous in nature, a paradox that has long puzzled evolutionary biologists. The Red Queen Hypothesis argues that outcrossing is maintained by antagonistic interactions between host and parasites. Most tests of this hypothesis focus on the maintenance of outcrossing in hosts. The Red Queen makes an additional prediction that parasitic taxa are more likely to be outcrossing than their free-living relatives. We test this prediction in the diverse Nematode phylum using phylogenetic comparative methods to evaluate trait correlations. In support of the Red Queen, we demonstrate a significant correlation between parasitism and outcrossing in this clade. We find that this correlation is driven by animal parasites, for which outcrossing is significantly enriched relative to both free-living and plant parasitic taxa. Finally, we test hypotheses for the evolutionary history underlying the correlation of outcrossing and animal parasitism. Our results demonstrate that selfing and asexuality are significantly less likely to arise on parasitic lineages than on free-living ones. The findings of this study are consistent with the Red Queen Hypothesis. Moreover, they suggest that the maintenance of genetic variation is an important factor in the persistence of parasitic lineages.

  17. A phylogenetic test of the Red Queen Hypothesis: Outcrossing and parasitism in the Nematode phylum

    PubMed Central

    Gibson, Amanda Kyle; Fuentes, Jesualdo Arturo

    2017-01-01

    Sexual outcrossing is costly relative to selfing and asexuality, yet it is ubiquitous in nature, a paradox that has long puzzled evolutionary biologists. The Red Queen Hypothesis argues that outcrossing is maintained by antagonistic interactions between host and parasites. Most tests of this hypothesis focus on the maintenance of outcrossing in hosts. The Red Queen makes an additional prediction that parasitic taxa are more likely to be outcrossing than their free-living relatives. We test this prediction in the diverse Nematode phylum using phylogenetic comparative methods to evaluate trait correlations. In support of the Red Queen, we demonstrate a significant correlation between parasitism and outcrossing in this clade. We find that this correlation is driven by animal parasites, for which outcrossing is significantly enriched relative to both free-living and plant parasitic taxa. Finally, we test hypotheses for the evolutionary history underlying the correlation of outcrossing and animal parasitism. Our results demonstrate that selfing and asexuality are significantly less likely to arise on parasitic lineages than on free-living ones. The findings of this study are consistent with the Red Queen Hypothesis. Moreover, they suggest that the maintenance of genetic variation is an important factor in the persistence of parasitic lineages. PMID:25403727

  18. On the track of the Red Queen: bark beetles, their nematodes, local climate and geographic parthenogenesis.

    PubMed

    Meirmans, S; Skorping, A; Løyning, M K; Kirkendall, L R

    2006-11-01

    Geographic parthenogenesis has been explained as resulting from parasite pressure (Red Queen hypothesis): several studies have found high degrees of sexuals where the prevalence of parasites is high. However, it is important to address whether prevalence of parasites mirrors risk of infection. We explored geographic parthenogenesis of Ips acuminatus bark beetles and their nematodes. Local climate is crucial for nematode stages outside the host, in spring and summer, and prevalence should thus be associated with those temperatures if prevalence reliably reflects exposure risk across populations. This was the case; however, high prevalence of a virulent nematode species was not associated with many sexuals, whereas highly sexual populations were characterized by high infection risk of benign nematodes. Low virulence of the latter makes Red Queen dynamics unlikely. Geographical patterns of parthenogenesis were instead associated with winter temperature and variance in temperature.

  19. Hill-Robertson Interference Maintained by Red Queen Dynamics Favours the Evolution of Sex.

    PubMed

    da Silva, Jack; Galbraith, James D

    2017-03-15

    Although it is well established theoretically that selective interference among mutations (Hill-Robertson interference) favours meiotic recombination, genome-wide mean rates of mutation and strengths of selection appear too low to support this as the mechanism favouring recombination in nature. A possible solution to this discrepancy between theory and observation is that selection is at least intermittently very strong due to the antagonistic coevolution between a host and its parasites. The Red Queen theory posits that such coevolution generates fitness epistasis among loci, which generates negative linkage disequilibrium among beneficial mutations, which in turn favours recombination. This theory has received only limited support. However, Red Queen dynamics without epistasis may provide the ecological conditions that maintain strong and frequent selective interference in finite populations that indirectly selects for recombination. This hypothesis is developed here through the simulation of Red Queen dynamics. This approach required the development of a method to calculate the exact frequencies of multi-locus haplotypes after recombination. Simulations show that recombination is favoured by the moderately weak selection of many loci involved in the interaction between a host and its parasites, which results in substitution rates that are compatible with empirical estimates. The model also reproduces the previously reported rapid increase in the rate of outcrossing in Caenorhabditis elegans coevolving with a bacterial pathogen. This article is protected by copyright. All rights reserved.

  20. Dynamic Red Queen Explains Patterns in Fatal Insurgent Attacks

    DTIC Science & Technology

    2011-03-01

    www.nytimes.com/2008/10/15/world/asia/15afghanistan.html http://www.independent.co.uk/news/world/asia/remember-afghanistan-insurgents-bring- suicide ...average and variance for R n( ) after n steps. Our notation for the change in R n( ) at step is . Hence the change between step 0 and is...the Red Queen’s walk over the n fatal days of the conflict (i.e. steps) increases as nb where b = 0.5. Using the more general notation of

  1. Parasites in sexual and asexual mollies (Poecilia, Poeciliidae, Teleostei): a case for the Red Queen?

    PubMed Central

    Tobler, Michael; Schlupp, Ingo

    2005-01-01

    The maintenance of sexual reproduction in the face of its supposed costs is a major paradox in evolutionary biology. The Red Queen hypothesis, which states that sex is an adaptation to fast-evolving parasites, is currently one of the most recognized explanations for the ubiquity of sex and predicts that asexual lineages should suffer from a higher parasite load if they coexist with closely related sexuals. We tested this prediction using four populations of the sexual fish species Poecilia latipinna and its asexual relative Poecilia formosa. Contrary to expectation, no differences in parasite load could be detected between the two species. PMID:17148156

  2. Parasites in sexual and asexual mollies (Poecilia, Poeciliidae, Teleostei): a case for the Red Queen?

    PubMed

    Tobler, Michael; Schlupp, Ingo

    2005-06-22

    The maintenance of sexual reproduction in the face of its supposed costs is a major paradox in evolutionary biology. The Red Queen hypothesis, which states that sex is an adaptation to fast-evolving parasites, is currently one of the most recognized explanations for the ubiquity of sex and predicts that asexual lineages should suffer from a higher parasite load if they coexist with closely related sexuals. We tested this prediction using four populations of the sexual fish species Poecilia latipinna and its asexual relative Poecilia formosa. Contrary to expectation, no differences in parasite load could be detected between the two species.

  3. Differences between selection on sex versus recombination in red queen models with diploid hosts.

    PubMed

    Agrawal, Aneil F

    2009-08-01

    The Red Queen hypothesis argues that parasites generate selection for genetic mixing (sex and recombination) in their hosts. A number of recent papers have examined this hypothesis using models with haploid hosts. In these haploid models, sex and recombination are selectively equivalent. However, sex and recombination are not equivalent in diploids because selection on sex depends on the consequences of segregation as well as recombination. Here I compare how parasites select on modifiers of sexual reproduction and modifiers of recombination rate. Across a wide set of parameters, parasites tend to select against both sex and recombination, though recombination is favored more often than is sex. There is little correspondence between the conditions favoring sex and those favoring recombination, indicating that the direction of selection on sex is often determined by the effects of segregation, not recombination. Moreover, when sex was favored it is usually due to a long-term advantage whereas short-term effects are often responsible for selection favoring recombination. These results strongly indicate that Red Queen models focusing exclusively on the effects of recombination cannot be used to infer the type of selection on sex that is generated by parasites on diploid hosts.

  4. The Red Queen in mitochondria: cyto-nuclear co-evolution, hybrid breakdown and human disease

    PubMed Central

    Chou, Jui-Yu; Leu, Jun-Yi

    2015-01-01

    Cyto-nuclear incompatibility, a specific form of Dobzhansky-Muller incompatibility caused by incompatible alleles between mitochondrial and nuclear genomes, has been suggested to play a critical role during speciation. Several features of the mitochondrial genome (mtDNA), including high mutation rate, dynamic genomic structure, and uniparental inheritance, make mtDNA more likely to accumulate mutations in the population. Once mtDNA has changed, the nuclear genome needs to play catch-up due to the intimate interactions between these two genomes. In two populations, if cyto-nuclear co-evolution is driven in different directions, it may eventually lead to hybrid incompatibility. Although cyto-nuclear incompatibility has been observed in a wide range of organisms, it remains unclear what type of mutations drives the co-evolution. Currently, evidence supporting adaptive mutations in mtDNA remains limited. On the other hand, it has been known that some mutations allow mtDNA to propagate more efficiently but compromise the host fitness (described as selfish mtDNA). Arms races between such selfish mtDNA and host nuclear genomes can accelerate cyto-nuclear co-evolution and lead to a phenomenon called the Red Queen Effect. Here, we discuss how the Red Queen Effect may contribute to the frequent observation of cyto-nuclear incompatibility and be the underlying driving force of some human mitochondrial diseases. PMID:26042149

  5. Peering through the looking glass at a sexual parasite: are Amazon mollies red queens?

    PubMed

    Dries, Laurie A

    2003-06-01

    The gynogenetic Amazon molly (Poecilia formosa) is a clonal, all-female lineage of livebearing fish that faces an unusual obstacle to evolutionary persistence. Sperm from heterospecific males (either sailfin, P. latipinna, or Atlantic, P. mexicana, mollies) is necessary to trigger embryogenesis. However, none of the male's genes are incorporated into the genome of the gynogenetic offspring. Some investigators have proposed that the evolution of male mate discrimination is a result of this cost, leading to a coevolutionary arms race between male avoidance of P. formosa and P. formosa attractiveness. Given that P. formosa successfully reproduces and has not yet gone extinct, it is clear there are mechanisms by which they attract the sexual attention of males. Although a Red Queen coevolutionary process in typical host/parasite systems has been shown to favor the persistence of sexual species, in this system an arms race has been invoked to explain the reverse. Here I present behavioral data supporting a more parsimonious scenario: that mechanisms of attraction in P. formosa are simply a consequence of its hybrid origin. Poecilia latipinna and P. mexicana males do not discriminate between gynogenetic P. formosa females and first generation sexual hybrid females, and females do not differ in agonistic behaviors associated with competition for mates. Both results contradict predictions from the Red Queen hypothesis. Therefore, coevolution is not necessary to explain the apparent evolutionary persistence of P. formosa.

  6. A General Class of Test Statistics for Van Valen’s Red Queen Hypothesis

    PubMed Central

    Wiltshire, Jelani; Huffer, Fred W.; Parker, William C.

    2014-01-01

    Van Valen’s Red Queen hypothesis states that within a homogeneous taxonomic group the age is statistically independent of the rate of extinction. The case of the Red Queen hypothesis being addressed here is when the homogeneous taxonomic group is a group of similar species. Since Van Valen’s work, various statistical approaches have been used to address the relationship between taxon age and the rate of extinction. We propose a general class of test statistics that can be used to test for the effect of age on the rate of extinction. These test statistics allow for a varying background rate of extinction and attempt to remove the effects of other covariates when assessing the effect of age on extinction. No model is assumed for the covariate effects. Instead we control for covariate effects by pairing or grouping together similar species. Simulations are used to compare the power of the statistics. We apply the test statistics to data on Foram extinctions and find that age has a positive effect on the rate of extinction. A derivation of the null distribution of one of the test statistics is provided in the supplementary material. PMID:24910489

  7. 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

  8. 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.

  9. A mean field model for competition: from neutral ecology to the Red Queen.

    PubMed

    O'Dwyer, James P; Chisholm, Ryan

    2014-08-01

    Individual species are distributed inhomogeneously over space and time, yet, within large communities of species, aggregated patterns of biodiversity seem to display nearly universal behaviour. Neutral models assume that an individual's demographic prospects are independent of its species identity. They have successfully predicted certain static, time-independent patterns. But they have generally failed to predict temporal patterns, such as species ages or population dynamics. We construct a new, multispecies framework incorporating competitive differences between species, and assess the impact of this competition on static and dynamic patterns of biodiversity. We solve this model exactly for the special case of a Red Queen hypothesis, where fitter species are continually arising. The model predicts more realistic species ages than neutral models, without greatly changing predictions for static species abundance distributions. Our modelling approach may allow users to incorporate a broad range of ecological mechanisms.

  10. 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.

  11. Who was the Red Queen? Identity of the female Maya dignitary from the sarcophagus tomb of Temple XIII, Palenque, Mexico.

    PubMed

    Tiesler, V; Cucina, A; Pacheco, A Romano

    2004-01-01

    The present investigation aims at contributing to the ongoing discussion on the unconfirmed identity of the Red Queen, a Classic Maya dignitary discovered in Temple XIII at Palenque, Mexico, by comparing her reconstructed facial profile to the portraiture of known female personages from the site. The comparison rests upon individual cranial features, like buccal prognatism, nasal root and inclination, chin prominence and the artificially shaped forehead. The similarities between the reconstruction, the female's funerary mask and local portraiture appear to identify the Red Queen as Lady Ix Tz'akb'u Ajaw (Ahpo Hel), the wife of Janaab' Pakal, one of the famous Maya rulers of the Classic Period. The proposed match and her family relationship with the king might explain the spatial closeness of their burial places in the Temple of the Inscriptions and Temple XIII.

  12. 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

  13. Infection dynamics in coexisting sexual and asexual host populations: support for the Red Queen hypothesis.

    PubMed

    Vergara, Daniela; Jokela, Jukka; Lively, Curtis M

    2014-08-01

    The persistence of sexual reproduction is a classic problem in evolutionary biology. The problem stems from the fact that, all else equal, asexual lineages should rapidly replace coexisting sexual individuals due to the cost of producing males in sexual populations. One possible countervailing advantage to sexual reproduction is that, on average, outcrossed offspring are more resistant than common clones to coevolving parasites, as predicted under the Red Queen hypothesis. In this study, we evaluated the prevalence of infection by a sterilizing trematode (Microphallus sp.) in a natural population of freshwater snails that was composed of both sexual and asexual individuals (Potamopyrgus antipodarum). More specifically, we compared the frequency of infection in sexual and asexual individuals over a 5-year period at four sites at a natural glacial lake (Lake Alexandrina, South Island, New Zealand). We found that at most sites and over most years, the sexual population was less infected than the coexisting asexual population. Moreover, the frequency of uninfected sexual females was periodically greater than two times the frequency of uninfected asexual females. These results give clear support for a fluctuating parasite-mediated advantage to sexual reproduction in a natural population.

  14. 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. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  15. How counterfactuals of Red-Queen theory shed light on science and its historiography.

    PubMed

    Dagg, Joachim L

    2017-08-01

    A historical episode of evolutionary theory, which has lead to the Red Queen theory of the evolutionary maintenance of sex, includes two striking contingencies. These are used to explore alternative what-if scenarios, in order to test some common opinions about such counterfactuals. This sheds new light on the nature of science and its historiography. One counterfactual leads to an unexpected convergence of its result to that of the actual science but, nevertheless, differs in its causal structure. The other diverges towards an incompatible alternative, but this requires further contingent choices that also diverge from actual science. The convergence in the first counterfactual is due to a horizontal transfer of knowledge. Similar transfers of knowledge are typical for innovations of actual science. This suggests that contingent choices can merge as well as fork research traditions both in actual research and counterfactual history. Neither the paths of the actual history of science nor those of its counterfactual alternatives will form a tree of exclusively diverging bifurcations, but a network instead. Convergencies in counterfactuals may, therefore, be due to the web-structure of science as much as to the aims of the historians in question. Furthermore, the difference in causal structure between the actual science and its convergent counterfactual might become diagnostic for external factors rather than internal aims forcing a historian towards convergence. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The Red Queen and the Court Jester: species diversity and the role of biotic and abiotic factors through time.

    PubMed

    Benton, Michael J

    2009-02-06

    Evolution may be dominated by biotic factors, as in the Red Queen model, or abiotic factors, as in the Court Jester model, or a mixture of both. The two models appear to operate predominantly over different geographic and temporal scales: Competition, predation, and other biotic factors shape ecosystems locally and over short time spans, but extrinsic factors such as climate and oceanographic and tectonic events shape larger-scale patterns regionally and globally, and through thousands and millions of years. Paleobiological studies suggest that species diversity is driven largely by abiotic factors such as climate, landscape, or food supply, and comparative phylogenetic approaches offer new insights into clade dynamics.

  17. Lotka-Volterra dynamics kills the Red Queen: population size fluctuations and associated stochasticity dramatically change host-parasite coevolution.

    PubMed

    Gokhale, Chaitanya S; Papkou, Andrei; Traulsen, Arne; Schulenburg, Hinrich

    2013-11-19

    Host-parasite coevolution is generally believed to follow Red Queen dynamics consisting of ongoing oscillations in the frequencies of interacting host and parasite alleles. This belief is founded on previous theoretical work, which assumes infinite or constant population size. To what extent are such sustained oscillations realistic? Here, we use a related mathematical modeling approach to demonstrate that ongoing Red Queen dynamics is unlikely. In fact, they collapse rapidly when two critical pieces of realism are acknowledged: (i) population size fluctuations, caused by the antagonism of the interaction in concordance with the Lotka-Volterra relationship; and (ii) stochasticity, acting in any finite population. Together, these two factors cause fast allele fixation. Fixation is not restricted to common alleles, as expected from drift, but also seen for originally rare alleles under a wide parameter space, potentially facilitating spread of novel variants. Our results call for a paradigm shift in our understanding of host-parasite coevolution, strongly suggesting that these are driven by recurrent selective sweeps rather than continuous allele oscillations.

  18. Lotka–Volterra dynamics kills the Red Queen: population size fluctuations and associated stochasticity dramatically change host-parasite coevolution

    PubMed Central

    2013-01-01

    Background Host-parasite coevolution is generally believed to follow Red Queen dynamics consisting of ongoing oscillations in the frequencies of interacting host and parasite alleles. This belief is founded on previous theoretical work, which assumes infinite or constant population size. To what extent are such sustained oscillations realistic? Results Here, we use a related mathematical modeling approach to demonstrate that ongoing Red Queen dynamics is unlikely. In fact, they collapse rapidly when two critical pieces of realism are acknowledged: (i) population size fluctuations, caused by the antagonism of the interaction in concordance with the Lotka-Volterra relationship; and (ii) stochasticity, acting in any finite population. Together, these two factors cause fast allele fixation. Fixation is not restricted to common alleles, as expected from drift, but also seen for originally rare alleles under a wide parameter space, potentially facilitating spread of novel variants. Conclusion Our results call for a paradigm shift in our understanding of host-parasite coevolution, strongly suggesting that these are driven by recurrent selective sweeps rather than continuous allele oscillations. PMID:24252104

  19. Coevolution of slow–fast populations: evolutionary sliding, evolutionary pseudo-equilibria and complex Red Queen dynamics

    PubMed Central

    Dercole, F; Ferrière, R; Gragnani, A; Rinaldi, S

    2006-01-01

    We study the interplay of ecological and evolutionary dynamics in communities composed of populations with contrasting time-scales. In such communities, genetic variation of individual traits can cause population transitions between stationary and cyclic ecological regimes, hence abrupt variations in fitness. Such abrupt variations raise ridges in the adaptive landscape, where the populations are poised between equilibrium and cyclic coexistence and along which evolutionary trajectories can remain sliding for long times or halt at special points called evolutionary pseudo-equilibria. These novel phenomena should be generic to all systems in which ecological interactions cause fitness to vary discontinuously. They are demonstrated by the analysis of a predator–prey community, with one adaptive trait for each population. The eco-evolutionary dynamics of the system show a number of other distinctive features, including evolutionary extinction and two forms of Red Queen dynamics. One of them is characterized by intermittent bouts of cyclic oscillations of the two populations. PMID:16627284

  20. 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

  1. 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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. 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. © 2014 Society of Chemical Industry.

  3. 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.

  4. Early Miocene catarrhine dietary behaviour: the influence of the Red Queen Effect on incisor shape and curvature.

    PubMed

    Deane, Andrew S

    2009-03-01

    Red Queen Effect (Van Valen, L., 1973. A new evolutionary law. Evol. Theory 1, 1-30), which predicts that taxa that are removed from one another by geological time, although potentially having similar diets, may exhibit differing degrees of a similar dietary adaptation (i.e., differing degrees of incisal curvature).

  5. 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.

  6. 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)

  7. Strangeness observables and pentaquarks

    SciTech Connect

    Kabana, Sonia

    2004-12-02

    We review the experimental evidence on firstly, strangeness production as a signature for the QCD phase transition and secondly, pentaquarks, the latest and most exotic manifestations of strangeness in hadrons.

  8. 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

  9. Goddard Queen Visit

    NASA Image and Video Library

    2007-05-07

    Queen Elizabeth II and Prince Philip, The Duke of Edinburgh look on as Goddard employees demonstrate “Science on a Sphere.” This system, developed by the National Oceanic and Atmospheric Administration (NOAA), uses computers and four video projectors to display animated images on the outside of a 6-foot diameter sphere. Photo Credit: (NASA/Pat Izzo)

  10. Goddard Queen Visit

    NASA Image and Video Library

    2007-05-07

    Queen Elizabeth II and NASA Administrator Michael Griffin plant a commemorative tree on the grounds of the visitor's center during a visit to NASA's Goddard Space Flight Center, Tuesday, May 8, 2007, in Greenbelt, Md. The Royal couple's appearance was one of the last stops on a six-day visit to the United States. Photo Credit (NASA/Debbie McCallum)

  11. 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.

  12. '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.

  13. 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

  14. 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

  15. 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

  16. Strangeness -2 hypertriton.

    PubMed

    Garcilazo, H; Valcarce, A

    2013-01-04

    We solve for the first time, the Faddeev equations for the bound state problem of the coupled ΛΛN-ΞNN system to study whether or not a hypertriton with strangeness -2 may exist. We make use of the interactions obtained from a chiral quark model describing the low-energy observables of the two-baryon systems with strangeness 0, -1, and -2 and three-baryon systems with strangeness 0 and -1. The ΛΛN system alone is unbound. However, when the full coupling to ΞNN is considered, the strangeness -2 three-baryon system with quantum numbers (I,J(P)) = (1/2,1/2(+)) becomes bound, with a binding energy of about 0.5 MeV. This result is compatible with the nonexistence of a stable (Λ)(3)H with isospin one.

  17. Strange nonchaotic stars.

    PubMed

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

    2015-02-06

    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.

  18. [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.

  19. "Sculpture of a Benin Queen."

    ERIC Educational Resources Information Center

    Guip, David

    1987-01-01

    Offers an art lesson for grades K-3 based on an early 19th century sculpture of the head of a Benin Queen. Presents background on the relevance of Queen Mother's position in Benin culture. Discusses importance of regalia and scarification associated with Benin heads. Includes suggestions for classroom activities. (BR)

  20. 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…

  1. 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…

  2. 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.

  3. 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

  4. Oocyte membrane localization of vitellogenin receptor coincides with queen flying age, and receptor silencing by RNAi disrupts egg formation in fire ant virgin queens.

    PubMed

    Lu, Hsiao-Ling; Vinson, S B; Pietrantonio, Patricia V

    2009-06-01

    In ant species in which mating flights are a strategic life-history trait for dispersal and reproduction, maturation of virgin queens occurs. However, the specific molecular mechanisms that mark this transition and the effectors that control premating ovarian growth are unknown. The vitellogenin receptor (VgR) is responsible for vitellogenin uptake during egg formation in insects. In the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), virgin queens have more abundant VgR transcripts than newly mated queens, but limited egg formation. To elucidate whether the transition to egg production involved changes in VgR expression, we investigated both virgin and mated queens. In both queens, western blot analysis showed an ovary-specific VgR band (approximately 202 kDa), and immunofluorescence analysis of ovaries detected differential VgR localization in early- and late-stage oocytes. However, the VgR signal was much lower in virgin queens ready to fly than in mated queens 8 h post mating flight. In virgin queens, the receptor signal was first observed at the oocyte membrane beginning at day 12 post emergence, coinciding with the 2 weeks of maturation required before a mating flight. Thus, the membrane localization of VgR appears to be a potential marker for queen mating readiness. Silencing of the receptor in virgin queens through RNA interference abolished egg formation, demonstrating that VgR is involved in fire ant ovary development pre mating. To our knowledge, this is the first report of RNA interference in any ant species and the first report of silencing of a hymenopteran VgR.

  5. Strangeness production at Saturne

    NASA Astrophysics Data System (ADS)

    Bertini, R.

    1995-02-01

    Since many years strangeness production is studied at Saturne in a large variety of experiments. I will remind here the work performed at the SPES4 facility by a Bonn-Orsay-Saclay collaboration and on the research program, in progress now, of the Dubna-Indiana-Saclay-Torino (DISTO) collaboration.

  6. 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)

  7. 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.

  8. 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

  9. Strange hadronic matter

    SciTech Connect

    Schafner, J. |; Dover, C.B. |; Gal, A. ||; Greiner, C. |; Stoecker, H. |

    1993-02-01

    In an extended mean field theory, there is found a large class of bound multi-strange objects, formed from combinations of (p,n,{Lambda} {Xi}{sup 0} {Xi}{sup {minus}}, baryons, which are stable against strong decay. A maximal binding energy per baryon of E{sub B}/A {approx} {minus}21 MeV, strangeness per baryon of {integral}{sub s} {approx} 1--1.2, charge per baryon of {integral}{sub q} {approx} {minus}-0.1 to 0.1, and baryon density of 2.5--3 times that of ordinary nuclei are predicted. For A {ge} 6, stable combinations involving only ({Lambda},{Xi}{sup 0},{Xi}) hyperons are obtained.

  10. 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.

  11. 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.

  12. Reflections on the "N" + "k" Queens Problem

    ERIC Educational Resources Information Center

    Chatham, Doug

    2009-01-01

    The "N" queens problem is a classic puzzle. It asks for an arrangement of "N" mutually non-attacking queens on an "N" x "N" chessboard. We discuss a recent variation called the "N" + "k" queens problem, where pawns are added to the chessboard to allow a greater number of non-attacking queens to be placed on it. We describe some of what is known…

  13. 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.

  14. 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.

  15. 'Queen of Hearts' Oakleaf Hydrangea

    USDA-ARS?s Scientific Manuscript database

    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 ...

  16. Stranger in a strange land

    NASA Astrophysics Data System (ADS)

    Steinberg, Peter

    2005-06-01

    The important new results and trends presented at Strangeness in Quark Matter 2004 are discussed. Particular emphasis is placed on strangeness and charm production, bulk dynamics, thermal models and the relevance of elementary systems to our understanding of heavy ion reactions. With of course, a nod to Robert A Heinlein, but without the messianic overtones.

  17. 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.

  18. 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

  19. 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

    2015-10-13

    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.

  20. 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.

  1. ``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.

  2. 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.

  3. Dispersal behavior of yellowjacket (Vespula germanica) queens.

    PubMed

    Masciocchi, Maité; Martinez, Andrés S; Pereira, Ana J; Villacide, José M; Corley, Juan C

    2016-06-30

    Understanding the factors that affect animal dispersal behavior is important from both fundamental and applied perspectives. Dispersal can have clear evolutionary and ecological consequences, but for nonnative insect pests, dispersal capacity can also help to explain invasion success. Vespula germanica is a social wasp that, in the last century, has successfully invaded several regions of the world, showing one of the highest spread rates reported for a nonnative insect. In contrast with nonsocial wasps, in social species, queens are responsible for population redistribution and spread, as workers are sterile. For V. germanica, it has been observed that queen flight is limited to 2 distinct periods: early autumn, when new queens leave the nest to mate and find sheltered places in which to hibernate, and spring when new colonies are founded. Our aim was to study the flight behavior of V. germanica queens by focusing on the different periods in which dispersal occurs, characterizing as well the potential contribution of queen flight (i.e., distance) to the observed geographical spread. Our results suggest that the distances flown by nonoverwintered queens is greater than that flown by overwintered individuals, suggesting that the main queen dispersal events would occur before queens enter hibernation. This could relate to a behavioral trait of the queens to avoid the inbreeding with related drones. Additionally, given the short distances flown and remarkable geographical spread observed, we provide evidence showing that queen dispersal by flight is likely to contribute proportionately less to population spread than human-aided factors.

  4. 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

    USDA-ARS?s Scientific Manuscript database

    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...

  5. 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.

  6. Grammatical complexity of strange sets

    NASA Astrophysics Data System (ADS)

    Auerbach, Ditza; Procaccia, Itamar

    1990-06-01

    Chaotic dynamical systems can be organized around an underlying strange set, which is comprised of all the unstable periodic orbits. In this paper, we quantify the complexity of such an organization; this complexity addresses the difficulty of predicting the structure of the strange set from low-order data and is independent of the entropy and the algorithmic complexity. We refer to the new measure as the grammatical complexity. The notion is introduced, discussed, and illustrated in the context of simple dynamical systems. In addition, the grammatical complexity is generalized to include metric properties arising due to the nonuniform distribution of the invariant measure on the strange set.

  7. Strange nucleon form-factors

    NASA Astrophysics Data System (ADS)

    Maas, F. E.; Paschke, K. D.

    2017-07-01

    A broad program measuring parity-violation in electron-nuclear scattering has now provided a large set of precision data on the weak-neutral-current form-factors of the proton. Under comparison with well-measured electromagnetic nucleon form-factors, these measurements reveal the role of the strange quark sea on the low-energy interactions of the proton through the strange-quark-flavor vector form-factors. This review will describe the experimental program and the implications of the global data for the strange-quark vector form-factors. We present here a new fit to the world data.

  8. 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.

  9. Strangeness and onset of deconfinement

    NASA Astrophysics Data System (ADS)

    Becattini, F.

    2012-05-01

    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.

  10. Effect of Irradiation on Queen Survivorship and Reproduction in the Invasive Fire Ant Solenopsis invicta (Hymenoptera: Formicidae) and a Proposed Phytosanitary Irradiation Treatment for Ants.

    PubMed

    Follett, Peter A; Porcel, Sol; Calcaterra, Luis A

    2016-12-01

    We studied radiation tolerance in queens of the red imported fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae) to identify a dose that prevents reproduction. Virgin or fertile queens were collected from Santa Fe and Formosa provinces in Argentina and reared in the laboratory in microcolonies. Virgin queens were irradiated at 0 (control), 70, 90, 120, or 150 Gy, and fertile queens were irradiated at 0, 60, 125, and 190 Gy, and then followed for 11 wk in the microcolonies to evaluate survival and reproduction. Virgin queens lay trophic eggs that do not hatch, whereas fertile queens lay eggs that hatch and develop into brood. In general, queen oviposition and survival decreased with increasing irradiation dose. For virgin queens, no eggs were laid by irradiated queens after the third week, whereas the control queens continued laying eggs throughout the 11-wk experiment. For fertile queens, only one larva and no pupae was observed in the 60 Gy treatment and no larvae or pupae were observed in the 125 and 190 Gy treatments, whereas a total of 431 larvae and 83 pupae were produced by untreated control queens during 11 wks. Survivorship of virgin and fertile queens was similarly reduced by irradiation treatment. These results with S. invicta are consistent with previous findings for three other invasive ants, Wasmannia auropunctata (Roger), Pheidole megacephala (F.), and Linephithema humile (Mayr), that are hitchhiker pests on fresh horticultural commodities. A radiation dose of 150 Gy is proposed as a phytosanitary treatment to prevent reproduction in ants. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.

  11. 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

  12. 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

  13. Magnetized strange quark matter and magnetized strange quark stars

    SciTech Connect

    Felipe, R. Gonzalez; Martinez, A. Perez; Rojas, H. Perez; Orsaria, M.

    2008-01-15

    Strange quark matter could be found in the core of neutron stars or forming strange quark stars. As is well known, these astrophysical objects are endowed with strong magnetic fields that affect the microscopic properties of matter and modify the macroscopic properties of the system. In this article we study the role of a strong magnetic field in the thermodynamical properties of a magnetized degenerate strange quark gas, taking into account {beta}-equilibrium and charge neutrality. Quarks and electrons interact with the magnetic field via their electric charges and anomalous magnetic moments. In contrast to the magnetic field value of 10{sup 19} G, obtained when anomalous magnetic moments are not taken into account, we find the upper bound B < or approx. 8.6x10{sup 17} G, for the stability of the system. A phase transition could be hidden for fields greater than this value.

  14. Strangeness asymmetry in the proton

    NASA Astrophysics Data System (ADS)

    Alberg, Mary

    2015-04-01

    Strangeness asymmetry in the proton may arise from fluctuations of the proton into meson-baryon pairs. The leading contributions to proton strangeness are from the KΛ , KΣ , K* Λ and K* Σ states. We use a Fock state expansion of the proton in terms of these pairs to represent the strange meson cloud. We determine the strangeness distributions of the proton in a hybrid convolution model, in which the fluctuations are represented either by light-cone wave functions or meson-baryon splitting functions. For the parton distributions of the s(s) quarks in the bare baryons(mesons) of the Fock states, we use light cone wave functions or our statistical model, which expands the bare hadrons in terms of quark-gluon states. The momentum distributions of the s and s quarks in each Fock state differ because they are constituents of different hadrons. We present our results for proton strangeness asymmetry, and compare them to NuTeV and to global parton distributions. This research has been supported in part by NSF Award 1205686.

  15. 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.

  16. Strangeness in hadronic stellar matter

    NASA Astrophysics Data System (ADS)

    Knorren, R.; Prakash, M.; Ellis, P. J.

    1995-12-01

    We examine the presence of strangeness-bearing components, hyperons and kaons, in dense neutron star matter. Calculations are performed using relativistic mean field models, in which both the baryon-baryon and kaon-baryon interactions are mediated by meson exchange. Results of kaon condensation are found to be qualitatively similar to previous work with chiral models, if compatibility of the kaon optical potentials is required. The presence of strangeness, be it in the form of hyperons or kaons, implies a reduction in the maximum mass and a relatively large number of protons, sufficient to allow rapid cooling to take place. The need to improve upon the poorly known couplings of the strange particles, which determine the composition and structure of neutron stars, is stressed. We also discuss generic problems with effective masses in mean field theories.

  17. Strangeness production at high baryon density

    NASA Astrophysics Data System (ADS)

    Satz, Helmut

    2016-08-01

    We propose to measure strange and non-strange hadron abundances at NICA in both AA and pp collisions, in order to test the validity range and possible extension schemes for present explanations of the energy and collision dependence of strange particle suppression.

  18. Strange nonchaotic self-oscillator

    NASA Astrophysics Data System (ADS)

    Jalnine, Alexey Yu.; Kuznetsov, Sergey P.

    2016-08-01

    An example of strange nonchaotic attractor (SNA) is discussed in a dissipative system of mechanical nature driven by a constant torque applied to one of the elements of the construction. So the external force is not oscillatory, and the system is autonomous. Components of the motion with incommensurable frequencies emerge due to the irrational ratio of the sizes of the involved rotating elements. We regard the phenomenon as strange nonchaotic self-oscillations, and its existence sheds new light on the question of feasibility of SNA in autonomous systems.

  19. 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

    ... Surface Transportation Board DeQueen and Eastern Railroad, LLC--Acquisition and Operation Exemption--DeQueen and Eastern Railroad Company DeQueen and Eastern Railroad, LLC (DQE), a noncarrier, has filed a verified notice of exemption under 49 CFR 1150.31 to acquire from DeQueen and Eastern Railroad Company and...

  20. 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.

  1. How strange is pion electroproduction?

    DOE PAGES

    Gorchtein, Mikhail; Spiesberger, Hubert; Zhang, Xilin

    2015-11-18

    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 constrainmore » 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 ReVγZ(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 ReVγZ(E = 0.155 GeV) = (1.1 ±0.2) ×10–3.« less

  2. Will strangeness win the prize?

    NASA Astrophysics Data System (ADS)

    Kapusta, Joseph I.

    2001-03-01

    Five groups have made predictions involving the production of strange hadrons and entered them in a competition set up by Barbara Jacak, Xin-Nian Wang and myself in the spring of 1998 for the purpose of comparing with first-year physics results from RHIC. These predictions are summarized and evaluated.

  3. Strange probes of the nucleus

    SciTech Connect

    Dover, C.B.

    1986-01-01

    Recent experimental and theoretical advances in hypernuclear physics are reviewed. An appraisal is given of various suggestions for using strange probes to test partial quark deconfinement in nuclei and meson exchange vs quark-gluon exchange descriptions of baryon-baryon interactions. 76 refs., 6 figs.

  4. 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.

  5. Queen of the giant storms

    NASA Astrophysics Data System (ADS)

    Beebe, Reta F.

    1990-10-01

    The observational history and present understanding of Jupiter's Great Red Spot (GRS) are reviewed. Analogies are drawn between earth's hurricanes and hot spots and the GRS. The results of computer modeling of the GRS are addressed.

  6. Asexually produced Cape honeybee queens (Apis mellifera capensis) reproduce sexually.

    PubMed

    Beekman, Madeleine; Allsopp, Michael H; Lim, Julianne; Goudie, Frances; Oldroyd, Benjamin P

    2011-01-01

    Unmated workers of the Cape honeybee Apis mellifera capensis can produce female offspring including daughter queens. As worker-laid queens are produced asexually, we wondered whether these asexually produced individuals reproduce asexually or sexually. We sampled 11 colonies headed by queens known to be the clonal offspring of workers and genotyped 23 worker offspring from each queen at 5 microsatellite loci. Without exception, asexually produced queens produced female worker offspring sexually. In addition, we report the replacement of a queen by her asexually produced granddaughter, with this asexually produced queen also producing offspring sexually. Hence, once a female larva is raised as a queen, mating and sexual reproduction appears to be obligatory in this subspecies, despite the fact that worker-laid queens are derived from asexual lineages.

  7. 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

  8. 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

  9. Pentaquarks and strange tetraquark mesons

    NASA Astrophysics Data System (ADS)

    Anisovich, V. V.; Matveev, M. A.; Sarantsev, A. V.; Semenova, A. N.

    2015-11-01

    We consider the interplay of the pentaquark states and strange tetraquark states in the decay Λb0 → K-J/ψp. Possible existence of (csc¯ū)-states is taken up and their manifestation in the K-J/ψ-channel is discussed. It is emphasized that these exotic mesons can imitate broad bumps in the pJ/ψ-channel.

  10. Strangeness exchange reactions and hypernuclei

    SciTech Connect

    Dover, C.B.

    1982-01-01

    Recent progress in the spectroscopy of ..lambda.. and ..sigma.. hypernuclei is reviewed. Prospects for the production of doubly strange hypernuclei at a future kaon factory are assessed. It is suggested that the (K/sup -/,K/sup +/) reaction on a nuclear target may afford an optimal way of producing the H dibaryon, a stable six quark object with J/sup ..pi../ = O/sup +/, S = -2.

  11. Strangeness in ALICE at the LHC

    NASA Astrophysics Data System (ADS)

    Bellini, Francesca; ALICE Collaboration

    2017-01-01

    Strangeness production has been measured by the ALICE experiment in different collision systems at the unprecedented center-of-mass energies available at the CERN Large Hadron Collider. In Pb–Pb collisions at TeV the relative production of strange and multi-strange baryons relative to pions is observed to follow a saturating trend with increasing centrality, and reaching values that are consistent with those predicted by thermal model calculations in the Grand-Canonical ensemble. More recently, the multiplicity dependence of strangeness production in small systems such as pp and p–Pb has also been investigated. An overview of the most recent results on strangeness production is reported, including the first observation of strangeness enhancement with charged particle multiplicity in pp collisions.

  12. Making a queen: an epigenetic analysis of the robustness of the honeybee (Apis mellifera) queen developmental pathway.

    PubMed

    He, Xu Jiang; Zhou, Lin Bin; Pan, Qi Zhong; Barron, Andrew B; Yan, Wei Yu; Zeng, Zhi Jiang

    2017-03-01

    Specialized castes are considered a key reason for the evolutionary and ecological success of the social insect lifestyle. The most essential caste distinction is between the fertile queen and the sterile workers. Honeybee (Apis mellifera) workers and queens are not genetically distinct, rather these different phenotypes are the result of epigenetically regulated divergent developmental pathways. This is an important phenomenon in understanding the evolution of social insect societies. Here, we studied the genomic regulation of the worker and queen developmental pathways, and the robustness of the pathways by transplanting eggs or young larvae to queen cells. Queens could be successfully reared from worker larvae transplanted up to 3 days age, but queens reared from older worker larvae had decreased queen body size and weight compared with queens from transplanted eggs. Gene expression analysis showed that queens raised from worker larvae differed from queens raised from eggs in the expression of genes involved in the immune system, caste differentiation, body development and longevity. DNA methylation levels were also higher in 3-day-old queen larvae raised from worker larvae compared with that raised from transplanted eggs identifying a possible mechanism stabilizing the two developmental paths. We propose that environmental (nutrition and space) changes induced by the commercial rearing practice result in a suboptimal queen phenotype via epigenetic processes, which may potentially contribute to the evolution of queen-worker dimorphism. This also has potentially contributed to the global increase in honeybee colony failure rates. © 2016 John Wiley & Sons Ltd.

  13. Balancing acts: drag queens, gender and faith.

    PubMed

    Sullivan-Blum, Constance R

    2004-01-01

    While engaged in research on the same-sex marriage debate in mainline denominations, I interviewed 23 LGBT Christians, four of whom were drag queens. While it is not possible to generalize from such a small sample, the drag queens in this study insist on maintaining their identity as Christians despite the hegemonic discourse that renders faith and LGBT identities mutually exclusive. They developed innovative approaches to reconciling their gender and sexual identities with their spirituality. Their innovations are potentially liberating not just for them personally, but for LGBT people generally because they challenge Christianity's rigid dichotomies of gender and sexuality.

  14. Queen Charlotte 2001 Earthquake Aftershock Sequence

    NASA Astrophysics Data System (ADS)

    Mulder, T.; Rogers, G. C.

    2012-12-01

    On Oct 12, 2001, an Mw=6.3 earthquake occurred off the Queen Charlotte Islands, BC. It was felt throughout Haida Gwaii (Queen Charlotte Islands) and the adjoining mainland. It generated a small tsunami recorded on Vancouver Island tide gauges. Moment tensor solutions show almost pure thrust faulting. There was a significant aftershock sequence associated with this event. Relocation of the catalogue aftershock sequence with respect to a key calibration event with various subsets of common stations show significant movement in the event locations. The aftershocks define an ~30 degree dipping fault plane.

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

    PubMed

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

    2007-10-03

    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.

  16. 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

  17. Additional strange hadrons from QCD thermodynamics and strangeness freezeout in heavy ion collisions.

    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

    2014-08-15

    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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Behavioral Plasticity in Ant Queens: Environmental Manipulation Induces Aggression among Normally Peaceful Queens in the Socially Polymorphic Ant Leptothorax acervorum

    PubMed Central

    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

  3. 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…

  4. 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…

  5. 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…

  6. 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…

  7. Red queen dynamics in specific predator-prey systems.

    PubMed

    Harris, Terence; Cai, Anna Q

    2015-10-01

    The dynamics of a predator-prey system are studied, with a comparison of discrete and continuous strategy spaces. For a [Formula: see text] system, the average strategies used in the discrete and continuous case are shown to be the same. It is further shown that the inclusion of constant prey switching in the discrete case can have a stabilising effect and reduce the number of available predator types through extinction.

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

    PubMed

    Green, David; Mason, Chris

    2013-08-21

    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. 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. 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.

  9. 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

  10. 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.

  11. 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.

  12. Queen volatiles as a modulator of Tetragonisca angustula drone behavior.

    PubMed

    Fierro, Macario M; Cruz-López, Leopoldo; Sánchez, Daniel; Villanueva-Gutiérrez, Rogel; Vandame, Remy

    2011-11-01

    Tetragonisca angustula mating occurs during the virgin queen nuptial flight, usually in the presence of a drone congregation area (DCA). The presence of virgin queen pheromone is considered the trigger for DCA establishment, although this has not been demonstrated experimentally. We established meliponaries, in different habitats, with T. angustula virgin queens during the main drone reproduction period. Eight DCAs were observed in urban areas, and all established outside or near colonies containing at least one virgin queen. The accumulation of drones in the DCAs occurred from 08:00 to 18:00 h and over 3-35 days. The number of drones in DCAs ranged from 60 to 2,000. In field trials, drones were attracted to virgin queens and also, unexpectedly, to physogastric queens. Volatiles collected from both virgin and physogastric queens elicited strong electoantennogram (EAG) responses from drones. Virgin and physogastric queen volatiles were qualitatively similar, but quantitatively different, in chemical composition. The queen's abdomen was the principal source of these compounds. Isopropyl hexanoate (IPH), the most abundant compound in virgin queen volatiles and one of the most abundant in physogastric queen volatiles, was identified as one of the compounds that elicited EAG responses and was demonstrated to attract drones in a field test.

  13. 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.

  14. Immune priming and pathogen resistance in ant queens

    PubMed Central

    Gálvez, Dumas; Chapuisat, Michel

    2014-01-01

    Growing empirical evidence indicates that invertebrates become more resistant to a pathogen following initial exposure to a nonlethal dose; yet the generality, mechanisms, and adaptive value of such immune priming are still under debate. Because life-history theory predicts that immune priming and large investment in immunity should be more frequent in long-lived species, we here tested for immune priming and pathogen resistance in ant queens, which have extraordinarily long life span. We exposed virgin and mated queens of Lasius niger and Formica selysi to a low dose of the entomopathogenic fungus Beauveria bassiana, before challenging them with a high dose of the same pathogen. We found evidence for immune priming in naturally mated queens of L. niger. In contrast, we found no sign of priming in virgin queens of L. niger, nor in virgin or experimentally mated queens of F. selysi, which indicates that immune priming in ant queens varies according to mating status and mating conditions or species. In both ant species, mated queens showed higher pathogen resistance than virgin queens, which suggests that mating triggers an up-regulation of the immune system. Overall, mated ant queens combine high reproductive output, very long life span, and elevated investment in immune defense. Hence, ant queens are able to invest heavily in both reproduction and maintenance, which can be explained by the fact that mature queens will be protected and nourished by their worker offspring. PMID:24963375

  15. Bottom-strange mesons in hyperonic matter

    NASA Astrophysics Data System (ADS)

    Pathak, Divakar; Mishra, Amruta

    2014-11-01

    The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of their medium mass on baryonic density and strangeness content of the medium. Certain aspects of these in-medium interactions are similar to those observed for the strange-charmed mesons in a preceding investigation, such as the lifting of mass-degeneracy of BS0 and {\\bar B}S0 mesons in hyperonic matter, while the same is respected in vacuum as well as in nuclear matter. In general, however, there is a remarkable distinction between the two species, even though the formalism predicts a completely analogous in-medium interaction Lagrangian density. We discuss in detail the reason for different in-medium behavior of these bottom-strange mesons as compared to charmed-strange mesons, despite the dynamics of the heavy quark being treated as frozen in both cases.

  16. and : candidates for charmed-strange mesons

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    Newly observed two charmed-strange resonances, and , are investigated by calculating their Okubo-Zweig-Iizuka-allowed strong decays, which shows that they are suitable candidates for the and states in the charmed-strange meson family. Our study also predicts other main decay modes of and , which can be accessible at the future experiment. In addition, the decay behaviors of the spin partners of and , i.e., and , are predicted in this work, which are still missing at present. The experimental search for the missing and charmed-strange mesons is an intriguing and challenging task for further experiments.

  17. Nuclear physics with strange particles

    SciTech Connect

    Dover, C.B.

    1988-01-01

    Recent progress in the understanding of strange particle interactions with nuclear systems is reviewed. We discuss the relative merits of various reactions such as (K/sup -/, ..pi../sup +-/), (..pi../sup +/, K/sup +/), or (..gamma.., K/sup +/) for hypernuclear production. The structure of /sub ..lambda..//sup 13/C is analyzed in some detail, in order to illustrate the role of the ..lambda..N residual interaction and approximate dynamical symmetries in hypernuclear structure. Recent results on the single particle states of a ..lambda.. in heavy systems, as revealed by (..pi../sup +/, K/sup +/) reaction studies, are used to extract information on the density dependence and effective mass which characterize the ..lambda..-nucleus mean field. Finally, we develop the idea the K/sup +/-nucleus scattering at low energies is sensitive to the subtle ''swelling'' effects for nucleons bound in nuclei. 64 refs., 13 figs.

  18. Ultrarelativistic cascades and strangeness production

    SciTech Connect

    Kahana, D.E.; Kahana, S.H.

    1998-02-01

    A two phase cascade, LUCIFER II, developed for the treatment of ultra high energy Ion-Ion collisions is applied to the production of strangeness at SPS energies. This simulation is able to simultaneously describe both hard processes such as Drell-Yan and slower, soft processes such as the production of light mesons by separating the dynamics into two steps, a fast cascade involving only the nucleons in the original colliding relativistic ions followed, after an appropriate delay, by a normal multiscattering of the resulting excited baryons and mesons produced virtually in the first step. No energy loss can take place in the short time interval over which the first cascade takes place. The chief result is a reconciliation of the important Drell-Yan measurements with the apparent success of standard cascades to describe the nucleon stopping and meson production in heavy ion experiments at the CERN SPS.

  19. REVISING A CLASSIC BUTTERFLY MIMICRY SCENARIO: DEMONSTRATION OF MÜLLERIAN MIMICRY BETWEEN FLORIDA VICEROYS (LIMENITIS ARCHIPPUS FLORIDENSIS) AND QUEENS (DANAUS GILIPPUS BERENICE).

    PubMed

    Ritland, David B

    1991-06-01

    Batesian and Müllerian mimicry relationships differ greatly in terms of selective pressures affecting the participants; hence, accurately characterizing a mimetic interaction is a crucial prerequisite to understanding the selective milieux of model, mimic, and predator. Florida viceroy butterflies (Limenitis archippus floridensis) are conventionally characterized as palatable Batesian mimics of distasteful Florida queens (Danaus gilippus berenice). However, recent experiments indicate that both butterflies are moderately distasteful, suggesting they may be Müllerian comimics. To directly test whether the butterflies exemplify Müllerian mimicry, I performed two reciprocal experiments using red-winged blackbird predators. In Experiment 1, each of eight birds was exposed to a series of eight queens as "models," then offered four choice trials involving a viceroy (the putative "mimic") versus a novel alternative butterfly. If mimicry was effective, viceroys should be attacked less than alternatives. I also compared the birds' reactions to solo viceroy "mimics" offered before and after queen models, hypothesizing that attack rate on the viceroy would decrease after birds had been exposed to queen models. In Experiment 2, 12 birds were tested with viceroys as models and queens as putative mimics. The experiments revealed that (1) viceroys and queens offered as models were both moderately unpalatable (only 16% entirely eaten), (2) some birds apparently developed conditioned aversions to viceroy or queen models after only eight exposures, (3) in the subsequent choice trials, viceroy and queen "mimics" were attacked significantly less than alternatives, and (4) solo postmodel mimics were attacked significantly less than solo premodel mimics. Therefore, under these experimental conditions, sampled Florida viceroys and queens are comimics and exemplify Müllerian, not Batesian, mimicry. This compels a reassessment of selective forces affecting the butterflies and their

  20. Queen pheromones in Temnothorax ants: control or honest signal?

    PubMed Central

    2011-01-01

    Background The division of reproductive labor among group members in insect societies is regulated by "queen pheromones". However, it remains controversial whether these are manipulative, i.e., actively suppress worker reproduction, or honestly signal the fertility status of the queen to which workers react in their own interest by refraining from laying eggs. Manipulative queen control is thought to lead to an evolutionary arms race between queens and workers, resulting in complex queen bouquets that diverge strongly among different populations and species. In contrast, honest signals would evolve more slowly and might therefore differ less strongly within and among species. Results We aimed at determining the tempo of the evolution of queen signals in two ways. First, we investigated whether queens of Temnothorax ants are capable of controlling egg laying by workers of their own, closely, and distantly related species. Second, we compared the species- and caste-specific patterns of cuticular hydrocarbons, which are assumed to convey information on reproductive status. In mixed-species colonies, queens were not able to fully suppress egg-laying and male production by workers of unrelated species, while workers did not reproduce under the influence of a queen from their own species. Furthermore, the chemical profiles differed more strongly among queens of different species than among the respective workers. Conclusions Our results suggest that cuticular hydrocarbons associated with fecundity are not fully conserved in evolution and evolve slightly faster than worker-specific components in the blend of cuticular hydrocarbons. While this higher rate of evolution might reflect an arms race between queens and workers, the observation that workers still respond to the presence of a queen from another species support the honest signal hypothesis. Future studies need to examine alternative explanations for a higher rate of evolution of queen-specific substances, such as

  1. Reproductive ultrasound of the bitch and queen.

    PubMed

    Davidson, Autumn P; Baker, Tomas W

    2009-05-01

    Ultrasonographic evaluation of the reproductive tract is an important component in the evaluation of the bitch and queen. Information is obtained concerning normal events involving the reproductive system (eg, ovulation, pregnancy) as well as pathologic conditions (eg, ovarian cysts, metritis). The appearance of the female reproductive tract normally changes with phases of the cycle; these changes need to be interpreted with knowledge of the ovarian cycle. Serial ultrasonographic evaluation of the diseased reproductive tract can be very helpful in evaluating response to therapy.

  2. Examination of strangeness instabilities and effects of strange meson couplings in dense strange hadronic matter and compact stars

    NASA Astrophysics Data System (ADS)

    Torres, James R.; Gulminelli, Francesca; Menezes, Débora P.

    2017-02-01

    Background: The emergence of hyperon degrees of freedom in neutron star matter has been associated to first-order phase transitions in some phenomenological models, but conclusions on the possible physical existence of an instability in the strangeness sector are strongly model dependent. Purpose: The purposes of the present study are to assess whether strangeness instabilities are related to specific values of the largely unconstrained hyperon interactions and to study the effect of the strange meson couplings on phenomenological properties of neutron stars and supernova matter, once these latter are fixed to fulfill the constraints imposed by hypernuclear data. Method: We consider a phenomenological relativistic mean field model (RMF) model sufficiently simple to allow a complete exploration of the parameter space. Results: We show that no instability at supersaturation density exists for the RMF model, as long as the parameter space is constrained by basic physical requirements. This is at variance with a nonrelativistic functional, with a functional behavior fitted through ab initio calculations. Once the study is extended to include the full octet, we show that the parameter space allows reasonable radii for canonical neutron stars as well as massive stars above two-solar mass, together with an important strangeness content of the order of 30%, slightly decreasing with increasing entropy, even in the absence of a strangeness-driven phase transition. Conclusions: We conclude that the hyperon content of neutron stars and supernova matter cannot be established with present constraints, and is essentially governed by the unconstrained coupling to the strange isoscalar meson.

  3. Strange and heavy mesons in hadronic matter

    NASA Astrophysics Data System (ADS)

    Cabrera, Daniel; Abreu, Luciano M.; Bratkovskaya, Elena; Ilner, Andrej; Llanes-Estrada, Felipe J.; Ramos, Angels; Tolos, Laura; Torres-Rincon, Juan M.

    2014-04-01

    We present selected results on the properties of strange and heavy-flavoured mesons in a hot and dense nuclear medium, with emphasis in selfconsistent coupled-channel approaches based on the chiral Lagrangian. In the strangeness sector, we discuss how the enhanced reactivity of light strange vectors at FAIR conditions can be tied to in-medium effects on their predominant decay modes (e.g. bar K* → bar Kπ) and to the excitation of strange baryons in vector-meson nucleon interactions. In the heavy-flavour sector, we focus on recent determinations of the transport coefficients of charmed and bottomed mesons in a hadron gas at vanishing baryonic chemical potential. We comment on the role of microscopic transport simulations to establish a connection between theoretical models and experimental observables from heavy-ion collisions (HICs).

  4. Nonstrange and strange pentaquarks with hidden charm

    NASA Astrophysics Data System (ADS)

    Anisovich, V. V.; Matveev, M. A.; Nyiri, J.; Sarantsev, A. V.; Semenova, A. N.

    2015-11-01

    Nonstrange and strange pentaquarks with hidden charm are considered as diquark-diquark-antiquark composite systems. Spin and isospin content of such exotic states is discussed and masses are evaluated.

  5. 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.

  6. 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)

  7. Bare strange quark stars: formation and emission

    NASA Astrophysics Data System (ADS)

    Xu, Renxin

    Recent achievements of bare strange stars are briefly reviewed. A nascent protostrange star should be bare because of strong mass ejection and high temperature after the supernova detonation flame, and a crust can also hardly form except for a super-Eddington accretion. The magnetosphere of a bare strange star is composed mainly of e± pair plasma, where both inner and outer vacuum gaps work for radio as well as high energy nonthermal emission. A featureless thermal spectrum is expected since no ion is above the quark surface, whilst electron cyclotron lines could appear in some bare strange stars with suitable magnetic fields. Various astrophysical implications of bare strange stars are discussed.

  8. 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)

  9. Strange Baryonic Matter and Kaon Condensation

    NASA Astrophysics Data System (ADS)

    Gazda, D.; Friedman, E.; Gal, A.; Mareš, J.

    In this contribution we address the question whether kaon condensation could occur in strongly interacting self-bound strange hadronic matter. In our comprehensive dynamical relativistic mean-field (RMF) calculations of nuclear and hypernuclear systems containing several antikaons we found saturation of bar K separation energy as well as the associated nuclear and bar K density distributions upon increasing the number of bar K mesons. The saturation pattern was found to be a universal feature of these multi-strangeness configurations. Since in all cases the bar K separation energy does not exceed 200 MeV, we conclude that bar K mesons do not provide the physical "strangeness" degrees of freedom for self-bound strange hadronic matter.

  10. Strangeness contributions to nucleon form factors

    SciTech Connect

    Ross Young

    2006-09-11

    We review a recent theoretical determination of the strange quark content of the electromagnetic form factors of the nucleon. These are compared with a global analysis of current experimental measurements in parity-violating electron scattering.

  11. 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.

  12. 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.

  13. [Did the Queen of Pount suffer from cutis laxa?].

    PubMed

    Martin, Jean-Pierre

    2010-12-01

    A bas-relief of the temple of Deir el-Bahari, Luxor, Egypt, discovered in 1867 by Mariette, shows a queen (Queen of Pount) with wide cutaneous folds on arms, abdomen and legs, hyperlordosis, a steatopygia and abnormally short lower limbs. Various assumptions about the diagnosis (steatopygia, partial achondroplasia, neurofibromatosis) were proposed at the beginning of the XXth century, neither taking into account all morphological abnormalities of the queen. We propose a novel hypothesis taking into account all signs: a Cutis Laxa.

  14. 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.

  15. Conservation of Queen Pheromones Across Two Species of Vespine Wasps.

    PubMed

    Oi, Cintia A; Millar, Jocelyn G; van Zweden, Jelle S; Wenseleers, Tom

    2016-11-01

    Social insects are known for their reproductive division of labor between queens and workers, whereby queens lay the majority of the colony's eggs, and workers engage mostly in non-reproductive tasks. Queens produce pheromones that signal their presence and fertility to workers, which in turn generally remain sterile. Recently, it has been discovered that specific queen-characteristic cuticular hydrocarbons (CHCs) function as queen pheromones across multiple lineages of social insects. In the common wasp, Vespula vulgaris, several long-chain linear alkanes and 3-methylalkanes were shown to act as queen signals. Here, we describe similar bioassays with a related species of highly eusocial vespine wasp, the Saxon wasp, Dolichovespula saxonica. We show that a blend of queen-characteristic hydrocarbons that are structurally related to those of the common wasp inhibit worker reproduction, suggesting conservation of queen pheromones across social wasps. Overall, our results highlight the central importance of CHCs in chemical communication among social insects in general, and as conserved queen pheromones in these social wasps in particular.

  16. Maternity of emergency queens in the Cape honey bee, Apis mellifera capensis.

    PubMed

    Holmes, Michael J; Oldroyd, Benjamin P; Allsopp, Michael H; Lim, Julianne; Wossler, Theresa C; Beekman, Madeleine

    2010-07-01

    During reproductive swarming, some workers of the Cape honey bee, Apis mellifera capensis, lay eggs in queen cells, many of which are reared to maturity. However, it is unknown if workers are able to lay in queen cells immediately after queen loss during an episode of emergency queen rearing. In this study we experimentally de-queened colonies and determined the maternity of larvae and pupae that were reared as queens. This allowed us to determine how soon after queen loss workers contribute to the production of new queens. We were further interested to see if workers would preferentially raise new queens from queen-laid brood if this was introduced later. We performed our manipulations in two different settings: an apiary setting where colonies were situated close together and a more natural situation in which the colonies were well separated. This allowed us to determine how the vicinity of other colonies affects the presence of parasites. We found that workers do indeed contribute to queen cell production immediately after the loss of their queen, thus demonstrating that some workers either have activated ovaries even when their colony has a queen or are able to activate their ovaries extremely rapidly. Queen-laid brood introduced days after queen loss was ignored, showing that workers do not prefer to raise new queens from queen brood when given a choice. We also detected non-natal parasitism of queen cells in both settings. We therefore conclude that some A. m. capensis genotypes specialize in parasitizing queen cells.

  17. 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)

  18. Queen succession through asexual reproduction in termites.

    PubMed

    Matsuura, Kenji; Vargo, Edward L; Kawatsu, Kazutaka; Labadie, Paul E; Nakano, Hiroko; Yashiro, Toshihisa; Tsuji, Kazuki

    2009-03-27

    The evolution and maintenance of sexual reproduction may involve important tradeoffs because asexual reproduction can double an individual's contribution to the gene pool but reduces diversity. Moreover, in social insects the maintenance of genetic diversity among workers may be important for colony growth and survival. We identified a previously unknown termite breeding system in which both parthenogenesis and sexual reproduction are conditionally used. Queens produce their replacements asexually but use normal sexual reproduction to produce other colony members. These findings show how eusociality can lead to extraordinary reproductive systems and provide important insights into the advantages and disadvantages of sex.

  19. Strangeness asymmetry in the proton sea

    NASA Astrophysics Data System (ADS)

    Alberg, Mary

    2015-10-01

    Meson cloud models describe the proton sea in terms of fluctuations of the proton into meson-baryon pairs. The leading contributions to proton strangeness are from states which contain a kaon and a Lambda or Sigma hyperon. We use a Fock state expansion of the proton in terms of these states to determine the strangeness distributions of the proton in a convolution model, in which the fluctuations are represented by meson-baryon splitting functions, which determine the total strangeness of the proton. Strangeness asymmetry, the difference between momentum distributions of the s and sbar quarks in the proton, arises because the quarks are constituents of different hadrons. For the parton distributions of the s(sbar) quarks in the bare baryons(mesons) of the Fock states, we use light cone wave functions or our statistical model, which expands the bare hadrons in terms of quark-gluon states. We show that strangeness asymmetry depends strongly on the parton distributions used for the hadrons in the cloud. We compare our results to NuTeV and to global parton distributions. This research has been supported in part by NSF Award 1205686.

  20. Vitellogenin, juvenile hormone, insulin signaling, and queen honey bee longevity

    PubMed Central

    Corona, Miguel; Velarde, Rodrigo A.; Remolina, Silvia; Moran-Lauter, Adrienne; Wang, Ying; Hughes, Kimberly A.; Robinson, Gene E.

    2007-01-01

    In most animals, longevity is achieved at the expense of fertility, but queen honey bees do not show this tradeoff. Queens are both long-lived and fertile, whereas workers, derived from the same genome, are both relatively short-lived and normally sterile. It has been suggested, on the basis of results from workers, that vitellogenin (Vg), best known as a yolk protein synthesized in the abdominal fat body, acts as an antioxidant to promote longevity in queen bees. We explored this hypothesis, as well as related roles of insulin–IGF-1 signaling and juvenile hormone. Vg was expressed in thorax and head fat body cells in an age-dependent manner, with old queens showing much higher expression than workers. In contrast, Vg expression in worker head was much lower. Queens also were more resistant to oxidative stress than workers. These results support the hypothesis that caste-specific differences in Vg expression are involved in queen longevity. Consistent with predictions from Drosophila, old queens had lower head expression of insulin-like peptide and its putative receptors than did old workers. Juvenile hormone affected the expression of Vg and insulin–IGF-1 signaling genes in opposite directions. These results suggest that conserved and species-specific mechanisms interact to regulate queen bee longevity without sacrificing fecundity. PMID:17438290

  1. 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.

  2. Momentum distributions of strange and anti-strange quarks in the proton

    NASA Astrophysics Data System (ADS)

    Hansen, Chase; Raschko, David; Netzel, Greg

    2013-10-01

    Strangeness in the proton has been confirmed by experiment. We are using the statistical method of Zhang et al., which explained the u - d asymmetry in the proton. We expand the model to include strange quarks, to explain the existence of strangeness in the proton. We used RAMBO in order to create a Bjorken-x distribution for the partons in the proton. We adjusted RAMBO to include the strange quark mass. In order to suppress the transitions to states that include s - s pairs, we calculate energy distributions for the gluons and allow gluons to split into s - s pairs only if the gluon is above the energy threshold of twice the mass of a strange quark. We expand our view to include the meson cloud model, attempting a different approach at explaining strangeness in the proton. After Q2 evolution, we compare our calculations of strangeness probability and S+ (x) to HERMES and ATLAS data, as well as global parton distribution fits. Supported in part by NSF Grants No. 0855656 and 1205686.

  3. 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.

  4. Intraspecific queen parasitism in a highly eusocial bee.

    PubMed

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

    2011-04-23

    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.

  5. 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.

  6. 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.

  7. Characterization of strange attractors as inhomogeneous fractals

    NASA Astrophysics Data System (ADS)

    Paladin, G.; Vulpiani, A.

    1984-09-01

    The geometry of strange attractors of chaotic dynamical systems is investigated analytically within the framework of fractal theory. A set of easily computable exponents which generalize the fractal dimensionality and characterize the inhomogeneity of the fractals of strange attractors is derived, and sample computations are shown. It is pointed out that the fragmentation process described is similar to models of intermittency in fully developed turbulence. The exponents for the sample problems are computed in the same amount of CPU time as the computation of nu by the method of Grassberger and Procaccia (1983) but provide more information; less time is required than for the nu(n) computation of Hentschel and Procaccia (1983).

  8. Electromagnetic signals from bare strange stars

    NASA Astrophysics Data System (ADS)

    Parisi, Alessandro

    2015-01-01

    Strange stars with a crystalline color superconducting crust can sustain large shear stresses, supporting torsional oscillations of large amplitude. We consider a simple model of strange star with a bare quark matter surface. When a torsional oscillation is excited, for example by a stellar glitch, the positive charge at the star surface oscillates, with typical kHz frequencies, for a 1km thick crust, to hundreds of Hz, for a 9km thick crust. Higher frequencies, of the order of few GHz, can be reached if the star crust is of the order of few centimeters thick. The estimated emitted power is of the order of 10^{45}{ erg/s}.

  9. 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.

  10. Strange behavior of rapidity dependent strangeness enhancement of particles containing and not containing leading quarks

    NASA Astrophysics Data System (ADS)

    Dey, Kalyan; Bhattacharjee, B.

    2017-09-01

    Rapidity dependent strangeness enhancement factors for the identified particles have been studied with the help of a string based hadronic transport model UrQMD-3.3 (Ultra-relativistic Quantum Molecular Dynamics) at FAIR energies. A strong rapidity dependent strangeness enhancement could be observed with our generated data for Au + Au collisions at the beam energy of 30A GeV. The strangeness enhancement is found to be maximum at mid-rapidity for the particles containing leading quarks while for particles consisting of produced quarks only, the situation is seen to be otherwise. Such rapidity dependent strangeness enhancement could be traced back to the dependence of rapidity width on centrality or otherwise on the distribution of net-baryon density.

  11. Dual effect of wasp queen pheromone in regulating insect sociality.

    PubMed

    Oi, Cintia A; Van Oystaeyen, Annette; Caliari Oliveira, Ricardo; Millar, Jocelyn G; Verstrepen, Kevin J; van Zweden, Jelle S; Wenseleers, Tom

    2015-06-15

    Eusocial insects exhibit a remarkable reproductive division of labor between queens and largely sterile workers [1, 2]. Recently, it was shown that queens of diverse groups of social insects employ specific, evolutionarily conserved cuticular hydrocarbons to signal their presence and inhibit worker reproduction [3]. Workers also recognize and discriminate between eggs laid by the queen and those laid by workers, with the latter being destroyed by workers in a process known as "policing" [4, 5]. Worker policing represents a classic example of a conflict-reducing mechanism, in which the reproductive monopoly of the queen is maintained through the selective destruction of worker-laid eggs [5, 6]. However, the exact signals used in worker policing have thus far remained elusive [5, 7]. Here, we show that in the common wasp, Vespula vulgaris, the pheromone that signals egg maternity and enables the workers to selectively destroy worker-laid eggs is in fact the same as one of the sterility-inducing queen signals that we identified earlier [3]. These results imply that queen pheromones regulate insect sociality in two distinct and complementary ways, i.e., by signaling the queen's presence and inhibiting worker reproduction, and by facilitating the recognition and policing of worker-laid eggs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. 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.

  13. Histiostoma Blomquisti N. SP. (Acari: Histiostomatidae) A phoretic mite of the red imported ant, Solenopsis Invicta Buren (Hymenoptera: Formicidae).

    Treesearch

    Stefan Wirth; John Moser

    2010-01-01

    The new species Histiostoma bJol1lquisti n. sp., associated with the Red Imported Fire Ant, Solenopsis invicta, is described by its deutonymph. A putative adult female is depicted. The deutonymphs only attach to female alates, dealates and queens of S. invicta. While queens may be covered by more than 200 deutonymphs over their entire bodies, the numbers of deutonymphs...

  14. 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.

  15. The mystery of the strange formulae

    NASA Astrophysics Data System (ADS)

    Bracken, Tony

    2016-10-01

    On a recent visit to the Wilhelm Röntgen memorial in Wurzburg, Germany, I noticed two strange trigonometric formulae set in the terrazzo floor at the western entrance to the building that houses Röntgen's X-ray laboratory.

  16. '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.

  17. 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.

  18. Strangeness chemical equilibration in a quark-gluon plasma

    SciTech Connect

    Letessier, Jean; Rafelski, Johann

    2007-01-15

    We study, in the dynamically evolving quark-gluon plasma (QGP) fireball formed in relativistic heavy ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC), the growth of strangeness yield toward and beyond the chemical equilibrium. We account for the contribution of the direct strangeness production and evaluate the thermal-QCD strangeness production mechanisms. The specific yield of strangeness per entropy, s/S, is the primary target variable. We explore the effect of collision impact parameter, i.e., fireball size, on kinetic strangeness chemical equilibration in QGP. Insights gained in studying the RHIC data with regard to the dynamics of the fireball are applied to the study of strangeness production at the LHC. We use these results and consider the strange hadron relative particle yields at RHIC and LHC in a systematic fashion. We consider both the dependence on s/S and the direct dependence on the participant number.

  19. Histological estimates of ovariole number in honey bee queens, Apis mellifera, reveal lack of correlation with other queen quality measures.

    PubMed

    Jackson, Jeffrey T; Tarpy, David R; Fahrbach, Susan E

    2011-01-01

    Published estimates of the number of ovarioles found in the ovaries of honey bee, Apis mellifera L. (Hymenoptera: Apidae) queens range from 100 to 180 per ovary. Within the context of a large-scale study designed to assay the overall quality of queens obtained from various commercial sources, a simple histology-based method for accurate determination of ovariole number was developed and then applied to a sample of 75 queens. Although all 10 commercial sources evaluated provided queens with ovariole numbers within the expected range, ovariole number was found to vary significantly across sources. Overall, and within most of the individual samples, there was no correlation of ovariole number with other morphological attributes such as thoracic width, wing length, or wet weight. Queens from two of the sources, however, displayed a significant negative relationship between wet weight and ovariole number. This study provides baseline data on ovariole number in commercial honey bee queens in the United States at a time when honey bee populations are declining; the method described can be used in studies relating ovariole number in queens to egg production and behavior.

  20. Histological Estimates of Ovariole Number in Honey Bee Queens, Apis mellifera, Reveal Lack of Correlation with other Queen Quality Measures

    PubMed Central

    Jackson, Jeffrey T.; Tarpy, David R.; Fahrbach, Susan E.

    2011-01-01

    Published estimates of the number of ovarioles found in the ovaries of honey bee, Apis mellifera L. (Hymenoptera: Apidae) queens range from 100 to 180 per ovary. Within the context of a large-scale study designed to assay the overall quality of queens obtained from various commercial sources, a simple histology-based method for accurate determination of ovariole number was developed and then applied to a sample of 75 queens. Although all 10 commercial sources evaluated provided queens with ovariole numbers within the expected range, ovariole number was found to vary significantly across sources. Overall, and within most of the individual samples, there was no correlation of ovariole number with other morphological attributes such as thoracic width, wing length, or wet weight. Queens from two of the sources, however, displayed a significant negative relationship between wet weight and ovariole number. This study provides baseline data on ovariole number in commercial honey bee queens in the United States at a time when honey bee populations are declining; the method described can be used in studies relating ovariole number in queens to egg production and behavior. PMID:21870968

  1. 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.

  2. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat and shell intact. (b) The operator of a vessel that fishes in the EEZ is responsible for ensuring...

  3. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat and shell intact. (b) The operator of a vessel that fishes in the EEZ is responsible for ensuring...

  4. 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

    2016-08-17

    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.

  5. 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

  6. Queen reproductive tract secretions enhance sperm motility in ants

    PubMed Central

    Baer, Boris; Boomsma, Jacobus J.

    2016-01-01

    Queens of Acromyrmex leaf-cutting ants store sperm of multiple males after a single mating flight, and never remate even though they may live for decades and lay tens of thousands of eggs. Sperm of different males are initially transferred to the bursa copulatrix and compete for access to the long-term storage organ of queens, but the factors determining storage success or failure have never been studied. We used in vitro experiments to show that reproductive tract secretions of Acromyrmex echinatior queens increase sperm swimming performance by at least 50% without discriminating between sperm of brothers and unrelated males. Indiscriminate female-induced sperm chemokinesis makes the likelihood of storage directly dependent on initial sperm viability and thus provides a simple mechanism to secure maximal possible reproductive success of queens, provided that initial sperm motility is an accurate predictor of viability during later egg fertilization. PMID:27807252

  7. 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

    2004-09-30

    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.

  8. Prudent sperm use by leaf-cutter ant queens

    PubMed Central

    den Boer, Susanne P. A.; Baer, Boris; Dreier, Stephanie; Aron, Serge; Nash, David R.; Boomsma, Jacobus J.

    2009-01-01

    In many species, females store sperm between copulation and egg fertilization, but the consequences of sperm storage and patterns of sperm use for female life history and reproductive success have not been investigated in great detail. In hymenopteran insect societies (ants, bees, wasps), reproduction is usually monopolized by one or relatively few queens, who mate only during a brief period early in life and store sperm for later use. The queens of some ants are particularly long-lived and have the potential to produce millions of offspring during their life. To do so, queens store many sperm cells, and this sperm must remain viable throughout the years of storage. Queens should also be under strong selection to use stored sperm prudently when fertilizing eggs. We used the leaf-cutter ant Atta colombica to investigate the dynamics of sperm use during egg fertilization. We show that queens are able to fertilize close to 100 per cent of the eggs and that the average sperm use per egg is very low, but increases with queen age. The robustness of stored sperm was found to decrease with years of storage, signifying that senescence affects sperm either directly or indirectly via the declining glandular secretions or deteriorating sperm-storage organs. We evaluate our findings with a heuristic model, which suggests that the average queen has sperm for almost 9 years of normal colony development. We discuss the extent to which leaf-cutter ant queens have been able to optimize their sperm expenditure and infer that our observed averages of sperm number, sperm robustness and sperm use are consistent with sperm depletion being a significant cause of mortality of mature colonies of Atta leaf-cutter ants. PMID:19710057

  9. Prudent sperm use by leaf-cutter ant queens.

    PubMed

    den Boer, Susanne P A; Baer, Boris; Dreier, Stephanie; Aron, Serge; Nash, David R; Boomsma, Jacobus J

    2009-11-22

    In many species, females store sperm between copulation and egg fertilization, but the consequences of sperm storage and patterns of sperm use for female life history and reproductive success have not been investigated in great detail. In hymenopteran insect societies (ants, bees, wasps), reproduction is usually monopolized by one or relatively few queens, who mate only during a brief period early in life and store sperm for later use. The queens of some ants are particularly long-lived and have the potential to produce millions of offspring during their life. To do so, queens store many sperm cells, and this sperm must remain viable throughout the years of storage. Queens should also be under strong selection to use stored sperm prudently when fertilizing eggs. We used the leaf-cutter ant Atta colombica to investigate the dynamics of sperm use during egg fertilization. We show that queens are able to fertilize close to 100 per cent of the eggs and that the average sperm use per egg is very low, but increases with queen age. The robustness of stored sperm was found to decrease with years of storage, signifying that senescence affects sperm either directly or indirectly via the declining glandular secretions or deteriorating sperm-storage organs. We evaluate our findings with a heuristic model, which suggests that the average queen has sperm for almost 9 years of normal colony development. We discuss the extent to which leaf-cutter ant queens have been able to optimize their sperm expenditure and infer that our observed averages of sperm number, sperm robustness and sperm use are consistent with sperm depletion being a significant cause of mortality of mature colonies of Atta leaf-cutter ants.

  10. Virgin queen attraction toward males in honey bees.

    PubMed

    Bastin, Florian; Cholé, Hanna; Lafon, Grégory; Sandoz, Jean-Christophe

    2017-07-24

    Although the honeybee is a crucial agricultural agent and a prominent scientific model organism, crucial aspects of its reproductive behaviour are still unknown. During the mating season, honeybee males, the drones, gather in congregations 10-40 m above ground. Converging evidence suggests that drones emit a pheromone that can attract other drones, thereby increasing the size of the congregation. Virgin queens join the vicinity of the congregation after it has formed, and mate with as many as 20 males in mid-air. It is still unclear which sensory cues help virgin queens find drone congregations in the first place. Beside visual cues for long-range orientation, queens may use olfactory cues. We thus tested virgin queens' olfactory orientation on a walking simulator in which they have full control over odour stimulation. We show that sexually-mature virgin queens are attracted to the odour bouquet from a group of living drones. They are not attracted to the bouquet from a group of workers. In addition, non-sexually receptive females (workers) of the same age are not attracted to the drone odour bouquet. Interpreted in the context of mating, these results may suggest that virgin queens use volatile olfactory cues from the drones to find the congregations.

  11. 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

  12. Phenomenology of strangeness production at high energies

    NASA Astrophysics Data System (ADS)

    Nasser Tawfik, Abdel; Yassin, Hayam; Abo Elyazeed, Eman R.; Maher, Muhammad; Magied Diab, Abdel; Abdel Wahab, Magda; Abou El Dahab, Eiman

    2016-12-01

    The strange-quark occupation factor (γ_s) is determined from the statistical fit of the multiplicity ratio {K}^+/π+ in a wide range of nucleon-nucleon center-of-mass energies (\\sqrt{sNN} ). From this single-strange-quark subsystem, γ_s(\\sqrt{sNN}) was parametrized as a damped trigonometric functionality and successfully implemented into the hadron resonance gas model, at chemical semi-equilibrium. Various particle ratios including {K}^-/ π- , Λ/π- , and \\barΛ/π- are well reproduced. The phenomenology of γ_s(\\sqrt{sNN}) suggests that the hadrons (γs rises) at \\sqrt{sNN} ≃ 7 \\text{GeV} seem to undergo a phase transition to a mixed phase (γs decreases), which is then derived into partons (γs remains unchanged with increasing \\sqrt{sNN} ), at \\sqrt{sNN} ≃ 20 \\text{GeV} .

  13. Analytical signal analysis of strange nonchaotic dynamics.

    PubMed

    Gupta, Kopal; Prasad, Awadhesh; Singh, Harinder P; Ramaswamy, Ramakrishna

    2008-04-01

    We apply an analytical signal analysis to strange nonchaotic dynamics. Through this technique it is possible to obtain the spectrum of instantaneous intrinsic mode frequencies that are present in a given signal. We find that the second-mode frequency and its variance are good order parameters for dynamical transitions from quasiperiodic tori to strange nonchaotic attractors (SNAs) and from SNAs to chaotic attractors. Phase fluctuation analysis shows that SNAs and chaotic attractors behave identically within short time windows as a consequence of local instabilities in the dynamics. In longer time windows, however, the globally stable character of SNAs becomes apparent. This methodology can be of great utility in the analysis of experimental time series, and representative applications are made to signals obtained from Rössler and Duffing oscillators.

  14. Unique signatures for QGP in strangeness sector

    NASA Astrophysics Data System (ADS)

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

    1998-03-01

    We suggest that the variations of certain strange particle ratios either with the energy density or with the baryon density constitute a significant signal for identification of the QGP formation in ultra-relativistic nucleus-nucleus collisions. We use realistic equations of state (EOS) for the QGP as well as for dense, hot hadron gas (HG) scenarios. We suggest that a direct comparison of the ratios obtained in the QGP and HG scenarios will be immensely helpful in identifying the QGP formation.

  15. The PANDA physics program: Strangeness and more

    SciTech Connect

    Iazzi, Felice; Collaboration: PANDA Collaboration

    2016-06-21

    The physics program of the PANDA experiment at FAIR is illustrated, with a particular attention to the planned activity in the field of the doubly strange systems. The investigation of these systems can help, among others, to shed light on the role of the hyperons in the composition of the neutron stars. The great advantages that can be reached in the field of the charmed systems and nucleon structure by using high quality and intense antiproton beams are also recalled.

  16. Calculation of the dimension of strange attractors

    NASA Astrophysics Data System (ADS)

    Malinetskii, G. G.; Potapov, A. B.

    1988-07-01

    Algorithms for calculating the dimension of strange attractors of dynamic systems are presented. Algorithms proposed for calculating the capacity, information dimension, and correlation index make it possible to reduce the amount of computations and the memory size. Calculations of the dimension of a Kantor set and a Feigenbaum attractor are considered as tests. Examples of calculations of the dimension of attractors of certain systems of ordinary differential equations are also considered.

  17. 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.

  18. 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.

  19. Spin and flavor strange quark content of the nucleon

    SciTech Connect

    Dahiya, Harleen; Gupta, Manmohan

    2008-07-01

    Several spin and flavor dependent parameters characterizing the strangeness content of the nucleon have been calculated in the chiral constituent quark model with configuration mixing ({chi}CQM{sub config}) which is known to provide a satisfactory explanation of the ''proton spin crisis'' and related issues. In particular, we have calculated the strange spin polarization {delta}s, the strangeness contribution to the weak axial vector couplings {delta}{sub 8} etc., strangeness contribution to the magnetic moments {mu}(p){sup s} etc., the strange quark flavor fraction f{sub s}, the strangeness dependent quark flavor ratios (2s/u+d) and (2s/u+d) etc. Our results are consistent with the recent experimental observations.

  20. Complete strangeness measurements in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Tomášik, Boris; Kolomeitsev, Evgeni E.

    2016-08-01

    We discuss strangeness production in heavy-ion collisions within and around the energy range of the planned NICA facility. We describe a minimal statistical model, in which the total strangeness yield is fixed by the observed or calculated K+ multiplicity. We show how the exact strangeness conservation can be taken into account on event-by-event basis in such a model. We argue that from strange particle yields one can reveal information about the collision dynamics and about possible modifications of particle properties in medium. This can be best achieved if the complete strangeness measurement is performed, i.e. kaons, antikaons, hyperons and multistrange hyperons are registered in the same experimental setup. In particular, production of hadrons containing two and more strange quarks, like Ξ and Ω baryons could be of interest.

  1. Strangeness production in antiproton annihilation on nuclei

    NASA Astrophysics Data System (ADS)

    Cugnon, J.; Deneye, P.; Vandermeulen, J.

    1990-04-01

    The strangeness production in antiproton annihilation on nuclei is investigated by means of a cascade-type model, within the frame of the conventional picture of the annihilation on a single nucleon followed by subsequent rescattering proceeding in the hadronic phase. The following hadrons are introduced: N, Λ, Σ, Λ¯, π, η, ω, K, and K¯ and, as far as possible, the experimental reaction cross sections are used in our simulation. The numerical results are compared with experimental data up to 4 GeV/c. The Λ¯ yield is correctly reproduced, while the Λ and Ks yields are overestimated in the p¯Ta and p¯Ne cases. On the other hand, the rapidity and perpendicular momentum distributions are well reproduced. It is shown that total strange yield is not very much affected by the associated production taking place during the rescattering process. It is also shown that the Λ/Ks ratio is largely due to the strangeness exchange reactions induced by antikaons. In particular, values of the order of 1 to 3 are expected in the energy range investigated here, independently of the detail of the hadronic phase dynamics. Finally, it is stressed that rapidity distributions are consistent with the rescattering process. Comparison with other works and implications of our results are examined.

  2. 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.

  3. 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.

  4. Strange quark contribution to the nucleon form factor

    NASA Astrophysics Data System (ADS)

    Baunack, S.

    PoS(Confinement8)078 According to QCD, the nucleon is made up of valence quarks, sea quarks and gluons. Concern- ing the quark sea, also strange quarks can contribute to the nucleon properties. Parity violating electron scattering offers a tool to investigate the strange quark contribution to the nucleon form factors parameterized by the strange form factors GE and Gs . The theoretical framework to ac- s M cess these strange form factors is outlined here and an overview of the existing world data is given. The measurements performed by the A4 collaboration at the electron accelerator facility MAMI are described here in more details and preliminary results are reported.

  5. Subdiffusion due to strange nonchaotic dynamics: a numerical study.

    PubMed

    Mitsui, Takahito

    2011-06-01

    We numerically investigate diffusion phenomena in quasiperiodically forced systems with spatially periodic potentials using a lift of the quasiperiodically forced circle map and a quasiperiodically forced damped pendulum. These systems exhibit several types of dynamics: quasiperiodic, strange nonchaotic, and chaotic. The strange nonchaotic and chaotic dynamics induce deterministic diffusion of orbits. The diffusion type gradually changes from logarithmic to subdiffusive within a strange nonchaotic regime and finally becomes normal in a chaotic regime. Fractal time-series analysis shows that the subdiffusion is caused by the antipersistence property of strange nonchaotic motion.

  6. Queen Quality and the Impact of Honey Bee Diseases on Queen Health: Potential for Interactions between Two Major Threats to Colony Health

    PubMed Central

    Amiri, Esmaeil; Strand, Micheline K.; Rueppell, Olav; Tarpy, David R.

    2017-01-01

    Western honey bees, Apis mellifera, live in highly eusocial colonies that are each typically headed by a single queen. The queen is the sole reproductive female in a healthy colony, and because long-term colony survival depends on her ability to produce a large number of offspring, queen health is essential for colony success. Honey bees have recently been experiencing considerable declines in colony health. Among a number of biotic and abiotic factors known to impact colony health, disease and queen failure are repeatedly reported as important factors underlying colony losses. Surprisingly, there are relatively few studies on the relationship and interaction between honey bee diseases and queen quality. It is critical to understand the negative impacts of pests and pathogens on queen health, how queen problems might enable disease, and how both factors influence colony health. Here, we review the current literature on queen reproductive potential and the impacts of honey bee parasites and pathogens on queens. We conclude by highlighting gaps in our knowledge on the combination of disease and queen failure to provide a perspective and prioritize further research to mitigate disease, improve queen quality, and ensure colony health. PMID:28481294

  7. Experimental evaluation of the reproductive quality of Africanized queen bees (Apis mellifera) on the basis of body weight at emergence.

    PubMed

    De Souza, D A; Bezzera-Laure, M A F; Francoy, T M; Gonçalves, L S

    2013-11-07

    There has been much speculation about which phenotypic traits serve as reliable indicators of productivity in queen honeybees (Apis mellifera). To investigate the predictive value of queen body weight on colony development and quality, we compared colonies in which queens weighed less than 180 mg to those in which queens weighed more than 200 mg. Both groups contained naturally mated and instrumentally inseminated queens. Colonies were evaluated on the basis of performance quality, growth rate, and queen longevity. We found that queen body weight was significantly correlated with fecundity and colony quality. Heavy queens exhibited the most favorable performance and colony quality. In contrast, naturally mated, with the opposite trend being obtained for light-weight queens. We found no statistically significant difference between instrumentally inseminated queens and naturally mated queens. Our results support the use of queen body weight as a reliable visual (physiological) indicator of potential colony productivity in honey bees to enhance genetic lines in genetic improvement programs.

  8. 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.

  9. 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.

  10. 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. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  11. Gene expression patterns associated with queen honey bee longevity.

    PubMed

    Corona, Miguel; Hughes, Kimberly A; Weaver, Daniel B; Robinson, Gene E

    2005-11-01

    The oxidative stress theory of aging proposes that accumulation of oxidative damage is the main proximate cause of aging and that lifespan is determined by the rate at which this damage occurs. Two predictions from this theory are that long-lived organisms produce fewer ROS or have increased antioxidant production. Based in these predictions, molecular mechanisms to promote longevity could include either changes in the regulation of mitochondrial genes that affect ROS production or elevated expression of antioxidant genes. We explored these possibilities in the honey bee, a good model for the study of aging because it has a caste system in which the same genome produces both a long-lived queen and a short-lived worker. We measured mRNA levels for genes encoding eight of the most prominent antioxidant enzymes and five mitochondrial proteins involved in respiration. The expression of antioxidant genes generally decreased with age in queens, but not in workers. Expression of most mitochondrial genes, in particular CytC, was higher in young queens, but these genes showed a faster age-related decline relative to workers. One exception to this trend was COX-I in thorax. This resulted in higher COX-I/CytC ratios in old queens compared to old workers, which suggests caste-specific differences in mitochondrial function that might be related to the caste-specific differences in longevity. Queen honey bee longevity appears to have evolved via mechanisms other than increased antioxidant gene expression.

  12. Venom Alkaloid and Cuticular Hydrocarbon Profiles Are Associated with Social Organization, Queen Fertility Status, and Queen Genotype in the Fire Ant Solenopsis invicta

    PubMed Central

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

    2013-01-01

    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

  13. 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.

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

    SciTech Connect

    Fabbietti, L.

    2016-01-22

    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{sup *} 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/c{sup 2} in the production of strange and non-strange hadrons is discussed. Experimental evidence for the presence of a Δ(2000){sup ++} 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.

  15. Strangeness in nuclei and neutron stars

    NASA Astrophysics Data System (ADS)

    Lonardoni, Diego

    2017-01-01

    The presence of exotic particles in the core of neutron stars (NS) has been questioned for a long time. At present, it is still an unsolved problem that drives intense research efforts, both theoretical and experimental. The appearance of strange baryons in the inner regions of a NS, where the density can exceed several times the nuclear saturation density, is likely to happen due to energetic considerations. The onset of strange degrees of freedom is considered as an effective mechanism to soften the equation of state (EoS). This softening affects the entire structure of the star, reducing the pressure and therefore the maximum mass that the star can stably support. The observation of two very massive NS with masses of the order of 2M⊙ seems instead to rule out soft EoS, apparently excluding the possibility of hyperon formation in the core of the star. This inconsistency, usually referred to as the hyperon puzzle, is based on what we currently know about the interaction between strange particles and normal nucleons. The combination of a poor knowledge of the hypernuclear interactions and the difficulty of obtaining clear astrophysical evidence of the presence of hyperons in NS makes the understanding of the behavior of strange degrees of freedom in NS an intriguing theoretical challenge. We give our contribution to the discussion by studying the general problem of the hyperon-nucleon interaction. We attack this issue by employing a quantum Monte Carlo (QMC) technique, that has proven to be successful in the description of strongly correlated Fermion systems, to the study of finite size nuclear systems including strange degrees of freedom, i.e. hypernuclei. We show that many-body hypernuclear forces are fundamental to properly reproduce the ground state physics of Λ hypernuclei from light- to medium-heavy. However, the poor abundance of experimental data on strange nuclei leaves room for a good deal of indetermination in the construction of hypernuclear

  16. Self Assessment in Insects: Honeybee Queens Know Their Own Strength

    PubMed Central

    Hepburn, Colleen; Hepburn, H. Randall; Jin, Shui-Hua; Crewe, Robin M.; Radloff, Sarah E.; Hu, Fu-Liang; Pirk, Christian W. W.

    2008-01-01

    Contests mediate access to reproductive opportunities in almost all species of animals. An important aspect of the evolution of contests is the reduction of the costs incurred during intra-specific encounters to a minimum. However, escalated fights are commonly lethal in some species like the honeybee, Apis mellifera. By experimentally reducing honeybee queens' fighting abilities, we demonstrate that they refrain from engaging in lethal contests that typically characterize their reproductive dominance behavior and coexist peacefully within a colony. This suggests that weak queens exploit an alternative reproductive strategy and provides an explanation for rare occurrences of queen cohabitation in nature. Our results further indicate that self-assessment, but not mutual assessment of fighting ability occurs prior to and during the agonistic encounters. PMID:18183293

  17. Onset of fights and mutual assessment in ant founding queens.

    PubMed

    Berthelot, Kévin; Portugal, Felipe Ramon; Jeanson, Raphaël

    2017-03-01

    In animals, the progress and outcome of contests can be influenced by an individual's own condition, their opponent's condition or a combination of the two. The use of chemical information to assess the quality of rivals has been underestimated despite its central role in the regulation of social interactions in many taxa. Here, we studied pairwise contests between founding queens of the ant Lasius niger to investigate whether the decision to engage in agonistic interactions relies on self-assessment or mutual assessment. Queens modulated their aggressive behaviours depending on both their own status and their opponent's status. We found no influence of lipid stores or size on the onset of fights. However, differences in cuticular chemical signatures linked to fertility status accurately predicted the probability of behaving aggressively in pairs. Our study thus suggests that ant queens could rely on mutual assessment via chemical cues to make informed decisions about fight initiation.

  18. Torsional Oscillations of Nonbare Strange Stars

    NASA Astrophysics Data System (ADS)

    Mannarelli, Massimo; Pagliaroli, Giulia; Parisi, Alessandro; Pilo, Luigi; Tonelli, Francesco

    2015-12-01

    Strange stars are one of the possible compact stellar objects that can form after a supernova collapse. We consider a model of a strange star having an inner core in the color-flavor locked phase surmounted by a crystalline color superconducting (CCSC) layer. These two phases constitute the quarksphere, which we assume to be the largest and heaviest part of the strange star. The next layer consists of standard nuclear matter forming an ionic crust, hovering on the top of the quarksphere and prevented from falling by a strong dipolar electric field. The dipolar electric field arises because quark matter is confined in the quarksphere by the strong interaction, but electrons can leak outside forming an electron layer a few hundred fermi thick separating the ionic crust from the underlying quark matter. The ionic matter and the CCSC matter constitute two electromagnetically coupled crust layers. We study the torsional oscillations of these two layers. Remarkably, we find that if a fraction larger than 10-4 of the energy of a Vela-like glitch is conveyed to a torsional oscillation, the ionic crust will likely break. The reason is that the very rigid and heavy CCSC crust layer will absorb only a small fraction of the glitch energy, leading to a large-amplitude torsional oscillation of the ionic crust. The maximum stress generated by the torsional oscillation is located inside the ionic crust and is very close to the star’s surface. This peculiar behavior leads to a much easier crust cracking than in standard neutron stars.

  19. TORSIONAL OSCILLATIONS OF NONBARE STRANGE STARS

    SciTech Connect

    Mannarelli, Massimo; Pagliaroli, Giulia; Parisi, Alessandro; Pilo, Luigi; Tonelli, Francesco

    2015-12-20

    Strange stars are one of the possible compact stellar objects that can form after a supernova collapse. We consider a model of a strange star having an inner core in the color-flavor locked phase surmounted by a crystalline color superconducting (CCSC) layer. These two phases constitute the quarksphere, which we assume to be the largest and heaviest part of the strange star. The next layer consists of standard nuclear matter forming an ionic crust, hovering on the top of the quarksphere and prevented from falling by a strong dipolar electric field. The dipolar electric field arises because quark matter is confined in the quarksphere by the strong interaction, but electrons can leak outside forming an electron layer a few hundred fermi thick separating the ionic crust from the underlying quark matter. The ionic matter and the CCSC matter constitute two electromagnetically coupled crust layers. We study the torsional oscillations of these two layers. Remarkably, we find that if a fraction larger than 10{sup −4} of the energy of a Vela-like glitch is conveyed to a torsional oscillation, the ionic crust will likely break. The reason is that the very rigid and heavy CCSC crust layer will absorb only a small fraction of the glitch energy, leading to a large-amplitude torsional oscillation of the ionic crust. The maximum stress generated by the torsional oscillation is located inside the ionic crust and is very close to the star’s surface. This peculiar behavior leads to a much easier crust cracking than in standard neutron stars.

  20. Results from CERN experiment NA36 on strangeness production

    SciTech Connect

    Not Available

    1991-12-01

    Measurements of the production of strange particles in the reactions S + Pb and S + S at beam momentum 200GeV/c per nucleon are presented. A short description of CERN experiment NA36 and the methods of raw data analysis, is followed by physics results concentrating on the dependence of strange particle production on multiplicity. Transverse momentum distributions are also presented.

  1. Strangeness and charm production in high energy heavy ion collisions

    SciTech Connect

    Xu, Nu

    2001-01-01

    We discuss the dynamical effects of strangeness and charm production in high energy nuclear collisions. In order to understand the early stage dynamical evolution, it is necessary to study the transverse momentum distributions of multi-strange hadrons like {Xi} and {Omega} and charm mesons like J/{Psi} as a function of collision centrality.

  2. Neutrino Dominated Accretion Flow Around a Strange Star

    NASA Astrophysics Data System (ADS)

    Zhibo, Hao; Zigao, Dai

    2013-10-01

    The "strange star - NDAF" model (NDAF: Neutrino Dominated Accretion Flow) is proposed as an alternative central engine of gamma-ray bursts for unifying the interpretation of the prompt emission and postburst activities of gamma-ray bursts. The structure of NDAF around a strange star is calculated. Different from other central compact objects, the strange star will feed back the phase transition energy of strangization on the accretion flow, with neutrinos as energy carriers. The friction between NDAF and strange star is ignored in this paper. The results indicate: firstly, the structure of NDAF around a strange star is sensitive to accretion rate; secondly, if accretion rate is larger than 0.18 Mʘ s-1, the "strange star - NDAF" model can unify the explanation on the prompt emission and postburst activities of gamma-ray bursts, and the range of allowable accretion rates is wider than that in frictionless "neutron star - NDAF" models; thirdly, the range of annihilation energy of "strange star - NDAF" model is very wide, when the accretion rate is higher than 0.3 Mʘ s-1, the annihilation energy is greater than 1051 erg; finally, if the accretion rate is greater than 0.3 Mʘ s-1, the annihilation energy of "strange star - NDAF" model is larger than what of "black hole - NDAF" model at the same accretion rate by more than one order of magnitude, it is favorable to explaining some extremely energetic gamma-ray bursts.

  3. 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.

  4. 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.

  5. The search for strange pentaquarks at ZEUS

    SciTech Connect

    Ren, Z.

    2005-10-06

    A study of states and enhancements reconstructed using the invariant-mass spectra associated with strange baryons has been performed in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 121 pb-1. The invariant-mass spectra were reconstructed in several kinematic regions with the main emphasis on the spectra which are sensitive to the production of pentaquarks. The candidate {theta}+ signal was found to be produced predominantly in the forward hemisphere in the laboratory frame. This is unlike the case for the {lambda}(1520) or the {lambda}c, and indicates that the {theta}+ may have an unusual production mechanism related to proton-remnant fragmentation.

  6. Associated strangeness production on light nuclei

    NASA Astrophysics Data System (ADS)

    Ernst, J.; Kingler, J.; Lippert, C.

    1991-04-01

    The study of light hyper-nuclei via associated strangeness production in (p, K+) reactions is discussed. Though the process is characterized by a very large momentum transfer the presence of short range correlations is expected to rise the cross section up to the order of nb/sr. Two approved proposals for high resolution studies of this reaction are discussed and respective detection limits are presented. The first is scheduled for October 1990 at the SPES4 spectrometer at the SATURNE acclerator (LNS Saclay). The second deals with the planned upgrading of the BIG KARL magnetic spectrograph at the cooled beam facility COSY being bulit at Forschungsanlage Jülich.

  7. 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.

  8. Kaon condensation and multi-strange matter

    NASA Astrophysics Data System (ADS)

    Gazda, D.; Friedman, E.; Gal, A.; Mareš, J.

    2010-04-01

    We report on dynamical calculations of multi- K¯ hypernuclei, which were performed by adding K¯ mesons to particle-stable configurations of nucleons, Λ and Ξ hyperons. The K¯ separation energy as well as the baryonic densities saturate with the number of antikaons. We demonstrate that the saturation is a robust feature of multi- K¯ hypernuclei. Because the K¯ separation energy B does not exceed 200 MeV, we conclude that kaon condensation is unlikely to occur in finite strong-interaction self-bound {N,Λ,Ξ} strange hadronic systems.

  9. Turbidity-current channels in Queen Inlet, Glacier Bay, Alaska

    USGS Publications Warehouse

    Carlson, P.R.; Powell, R.D.; Rearic, D.M.

    1989-01-01

    Queen Inlet is unique among Glacier Bay fjords because it alone has a branching channel system incised in the Holocene sediment fill of the fjord floor. Queen Inlet and other known channel-containing fjords are marine-outwash fjords; the tidewater glacial fjords do not have steep delta fronts on which slides are generated and may not have a sufficient reservoir of potentially unstable coarse sediment to generate channel-cutting turbidity currents. Presence or absence of channels, as revealed in the ancient rock record, may be one criterion for interpreting types of fjords. -Authors

  10. Prediction of parturition date in the bitch and queen.

    PubMed

    Michel, E; Spörri, M; Ohlerth, S; Reichler, Im

    2011-10-01

    Assessment of gestational age and parturition date prediction is a challenging, yet common task in clinical management of the pregnant bitch or queen. Knowing the approximate parturition date is essential for a thorough pregnancy monitoring. Radiographic and ultrasonographic methods are suitable in bitches and queens. In the bitch, moreover, ovulation timing by means of LH or progesterone assay, determination of onset of vaginal dioestrus by means of examination of vaginal cytology, and recognition of impending parturition by monitoring prepartal progesterone levels and body temperature variation are practical methods. A combination of different methods increases the accuracy of parturition date prediction.

  11. 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.

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

    PubMed

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

    2016-09-09

    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.

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

    USDA-ARS?s Scientific Manuscript database

    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 ...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  15. 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

  16. Hormonal pleiotropy helps maintain queen signal honesty in a highly eusocial wasp.

    PubMed

    Oliveira, Ricardo Caliari; Vollet-Neto, Ayrton; Akemi Oi, Cintia; van Zweden, Jelle S; Nascimento, Fabio; Sullivan Brent, Colin; Wenseleers, Tom

    2017-05-10

    In insect societies, both queens and workers produce chemicals that reliably signal caste membership and reproductive status. The mechanisms that help to maintain the honesty of such queen and fertility signals, however, remain poorly studied. Here we test if queen signal honesty could be based on the shared endocrine control of queen fertility and the production of specific signals. In support of this "hormonal pleiotropy" hypothesis, we find that in the common wasp, application of methoprene (a juveline hormone analogue) caused workers to acquire a queen-like cuticular hydrocarbon profile, resulting in the overproduction of known queen pheromones as well as some compounds typically linked to worker fertility. By contrast, administration of precocene-I (a JH inhibitor) had a tendency to have the opposite effect. Furthermore, a clear gonadotropic effect of JH in queens was suggested by the fact that circulating levels of JH were ca. 2 orders of magnitude higher in queens than those in workers and virgin, non-egg-laying queens, even if methoprene or precocene treatment did not affect the ovary development of workers. Overall, these results suggest that queen signal honesty in this system is maintained by queen fertility and queen signal production being under shared endocrine control.

  17. Selection against aerial dispersal in ants: two non-flying queen phenotypes in Pogonomyrmex laticeps.

    PubMed

    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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  19. Hormonal pleiotropy helps maintain queen signal honesty in a highly eusocial wasp

    USDA-ARS?s Scientific Manuscript database

    In insect societies, both queens and workers produce chemicals that reliably signal caste membership and reproductive status. The mechanisms that help to maintain the honesty of such queen and fertility signals, however, remain poorly studied. Here we test if queen signal honesty could be based on t...

  20. 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.

  1. Radial stability of anisotropic strange quark stars

    NASA Astrophysics Data System (ADS)

    Arbañil, José D. V.; Malheiro, M.

    2016-11-01

    The influence of the anisotropy in the equilibrium and stability of strange stars is investigated through the numerical solution of the hydrostatic equilibrium equation and the radial oscillation equation, both modified from their original version to include this effect. The strange matter inside the quark stars is described by the MIT bag model equation of state. For the anisotropy two different kinds of local anisotropic σ = pt-pr are considered, where pt and pr are respectively the tangential and the radial pressure: one that is null at the star's surface defined by pr(R) = 0, and one that is nonnull at the surface, namely, σs = 0 and σs ≠ 0. In the case σs = 0, the maximum mass value and the zero frequency of oscillation are found at the same central energy density, indicating that the maximum mass marks the onset of the instability. For the case σs ≠ 0, we show that the maximum mass point and the zero frequency of oscillation coincide in the same central energy density value only in a sequence of equilibrium configurations with the same value of σs. Thus, the stability star regions are determined always by the condition dM/dρc > 0 only when the tangential pressure is maintained fixed at the star surface's pt(R). These results are also quite important to analyze the stability of other anisotropic compact objects such as neutron stars, boson stars and gravastars.

  2. Singularity-free anisotropic strange quintessence star

    NASA Astrophysics Data System (ADS)

    Bhar, Piyali

    2015-04-01

    Present paper provides a new model of anisotropic strange star corresponding to the exterior Schwarzschild metric. The Einstein field equations have been solved by utilizing the Krori-Barua (KB) ansatz (Krori and Barua in J. Phys. A, Math. Gen. 8:508, 1975) in presence of quintessence field characterized by a parameter ω q with . The obtained solutions are free from central singularity. Our model is potentially stable. The numerical values of mass of the different strange stars SAXJ1808.4-3658(SS1) (radius=7.07 km), 4U1820-30 (radius=10 km), Vela X-12 (radius=9.99 km), PSR J 1614-2230 (radius=10.3 km) obtained from our model is very close to the observational data that confirms the validity of our proposed model. The interior solution is also matched to the exterior Schwarzschild spacetime in presence of thin shell where negative surface pressure is required to hold the thin shell against collapsing.

  3. Strangeness production with polarized protons at Saturne

    NASA Astrophysics Data System (ADS)

    Choi, Seonho

    1998-08-01

    At high energies, significant polarization effects have long been observed in inclusive Λ production from the collision of unpolarized hadrons. Although many experiments on hyperon production have been performed, very few used polarized hadron beams and none have involved exclusive measurements. An independent puzzle in the strangeness sector has been revealed by recent observations of a large violation of the Okubo-Zweig-Iizuka (OZI) rule in φ-meson production by anti-protons. These violations have been interpreted by some to indicate sizeable strange-quark content of the nucleon. Understanding these two problems constitutes the major goal of the DISTO program at Saturne. The DISTO experiment is designed to study hyperons (Λ, Σ) and vector mesons (φ, ω) produced in p-->p collisions at three incident proton momenta: 3.67, 3.31 and 2.94GeV/c. Detection of all charged particles in the final state allows exclusive measurements for hyperons, while the use of polarized beam makes it possible to measure analyzing powers Ay and the spin transfer coefficient DNN, in addition to the polarization of the outgoing hyperon. An outline of the physics motivation and a brief description of the experimental setup is given. Some preliminary results from the data taken at 3.67GeV/c are presented.

  4. Strangeness in STAR experiment at RHIC

    NASA Astrophysics Data System (ADS)

    Shi, Shusu; STAR collaboration

    2017-01-01

    We present the recent results of strangeness production at the mid-rapidity in Au + Au collisions at RHIC, from to 200 GeV. Elliptic asymmetry v 2 of multi-strange baryon Ω and φ mesons are similar to that of pions and protons in the intermediate pT range (2 - 5 GeV/c) in GeV Au + Au collisions, indicating that the major part of collective ow has been built up at partonic stage. The breaking of mass ordering between φ mesons and protons in the low pT range (< 1 GeV/c) is consistent with a picture that φ mesons are less sensitive to later hadronic interaction. The nuclear modification factor R CP and baryon to meson ratio change dramatically when the collision energy is lower than 19.6 GeV. It suggests a possible change of the created QCD medium properties at lower energies compared to those from high energies.

  5. Strange Particles and Heavy Ion Physics

    SciTech Connect

    Bassalleck, Bernd; Fields, Douglas

    2016-04-28

    This very long-running grant has supported many experiments in nuclear and particle physics by a group from the University of New Mexico. The gamut of these experiments runs from many aspects of Strangeness Nuclear Physics, to rare Kaon decays, to searches for exotic Hadrons such as Pentaquark or H-Dibaryon, and finally to Spin Physics within the PHENIX collaboration at RHIC. These experiments were performed at a number of laboratories worldwide: first and foremost at Brookhaven National Lab (BNL), but also at CERN, KEK, and most recently at J-PARC. In this Final Technical Report we summarize progress and achievements for this award since our last Progress Report, i.e. for the period of fall 2013 until the award’s termination on November 30, 2015. The report consists of two parts, representing our two most recent experimental efforts, participation in the Nucleon Spin Physics program of the PHENIX experiment at RHIC, the Relativistic Heavy Ion Collider at BNL – Task 1, led by Douglas Fields; and participation in several Strangeness Nuclear Physics experiments at J-PARC, the Japan Proton Accelerator Research Center in Tokai-mura, Japan – Task 2, led by Bernd Bassalleck.

  6. Strangeness electroproduction on the nucleon at CLAS

    NASA Astrophysics Data System (ADS)

    Carman, Daniel S.; CLAS Collaboration

    2012-04-01

    High-precision measurements of strange particle production from both proton and neutron targets are a core part of the physics programwith 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+Y (Y = ΛΣ0) final states over a broad kinematic range in momentum transfer Q2 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 productionmechanisms for Λ and Σ 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.

  7. Tremors Triggered along the Queen Charlotte Fault

    NASA Astrophysics Data System (ADS)

    Aiken, C.; Peng, Z.; Chao, K.

    2012-12-01

    In the past decade, deep tectonic tremors have been observed in numerous tectonic environments surrounding the Pacific and Caribbean plates. In these regions, tremors triggered by both regional and distant earthquakes have also been observed. Despite the ubiquitous observations of triggered tremors, tremors triggered in differing strike-slip environments are less understood. Here, we conduct a preliminary search of tremors triggered by teleseismic earthquakes along the transpressive Queen Charlotte Fault (QCF) located between the Cascadia subduction zone and Alaska. Tectonic tremors have not been previously reported along the QCF. We select teleseismic earthquakes during the 1990-2012 period as having magnitude M ≥ 6.5 and occurring at least 1,000 km away from the region. We reduce the number of mainshocks by selecting those that generate greater than 1 kPa dynamic stress estimated from surface-wave magnitude equations [e.g. van der Elst and Brodsky, 2010]. Our mainshock waveforms are retrieved from the Canadian National Seismograph Network (CNSN), processed, and filtered for triggered tremor observations. We characterize triggered tremors as high-frequency signals visible among several stations and coincident with broadband surface wave peaks. So far, we have found tremors triggered along the QCF by surface waves of five great earthquakes - the 2002/11/03 Mw7.9 Denali Fault, 2004/12/26 Mw9.0 Sumatra, 2010/02/27 Mw8.8 Chile, 2011/03/11 Mw9.0 Japan, and 2012/04/11 Mw8.6 Sumatra earthquakes. We compare our results to tremors triggered by teleseismic earthquakes on strike-slip faults in central and southern California, as well as Cuba [Peng et al., 2012]. Among strike-slip faults in these regions, we also compare triggered tremor amplitudes to peak ground velocities from the mainshocks and compute dynamic stresses to determine a triggering threshold for the QCF. We find that in most cases tremors in the QCF are triggered primarily by the Love waves, and additional

  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. 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

  10. Ross Ice Shelf and the Queen Maude Mounains, Antarctica

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Part of the Ross Ice Shelf and the Queen Maude Mounains of Antarctica (55.5N, 178.0W) are in the background of this scene, oriented toward the south. Low stratocumulus clouds are predominant throughout most of the scene.

  11. Six Immigrant Groups in Queens: A Pilot Study.

    ERIC Educational Resources Information Center

    Grant, Geraldine S.

    This research report summarizes data on six new immigrant groups, Colombians, Italians, Greeks, Koreans, Asian Indians, and Israelis, living in the Borough of Queens in New York City. The research format consisted of a comprehensive interview administered to 116 households. Data on occupation, education, income, household composition,…

  12. High Schools Performance Indicators Profile, 1999-2000: Queens Superintendency.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn. Div. of Assessment and Accountability.

    This report presents data on high school performance indicators for the 1999-00 school year in Queens, New York. Data are provided on: background; students (numbers and ethnicity); state accountability indicators in English and language arts (full cohort and seniors in the cohort); state accountability indicators in mathematics (full cohort);…

  13. 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…

  14. Queen leads tributes to nurses in wake of terrorist attacks.

    PubMed

    Allen, Daniel

    2017-06-15

    The Queen and the prime minister led tributes to nurses and other NHS staff caring for people injured in the recent terrorist attacks in Manchester and London. Emergency services worked through the night to assist in the immediate aftermath of the explosion at the Manchester arena, which killed 22 people and left many more injured, who were treated at hospitals across the city.

  15. Ross Ice Shelf and the Queen Maude Mounains, Antarctica

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Part of the Ross Ice Shelf and the Queen Maude Mounains of Antarctica (55.5N, 178.0W) are in the background of this scene, oriented toward the south. Low stratocumulus clouds are predominant throughout most of the scene.

  16. Deep seismic reflection survey of Queen Charlotte basin

    SciTech Connect

    Rohr, K.; Dietrich, J. )

    1990-05-01

    One thousand kilometers of 14 sec marine seismic reflection data collected in the Queen Charlotte basin region in 1988 provide excellent images of Tertiary sedimentary basin fill as well as deep crustal structure. The Tertiary section is highly variable in thickness, with up to 6,500 m of strata occurring in the deepest depocenters in a complex array of subbasins and half-grabens. Widespread extensional deformation including normal faulting during basin development was followed later by compressional deformation in the northern half of the basin. Sediments have been compressed into open folds and flower structures; some normal faults have been reactivated as reverse faults. Seismic interpretations of structural features suggest that Tertiary extension and compression have developed in response to strike-slip tectonics. Crust under Hecate Strait is more reflective than under Queen Charlotte Sound; geological interpretation of these discontinuous and structurally variable crustal reflections requires further analysis. In some areas of the basin (e.g., near the Sockeye wells, Hecate Strait) coherent reflections occur directly beneath the Tertiary section and may be images of Mesozoic strata. Deep reflections damaged at times of 7.0 to 10.0 sec on many profiles, provide for the seismic differentiation between reflective lower crust and nonreflective upper mantle. Estimated crustal thicknesses of 18-21 km beneath Hecate Strait and Queen Charlotte Sound indicate significant coastal thinning beneath the Queen Charlotte basin.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  18. Identification of an ant queen pheromone regulating worker sterility

    PubMed Central

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

    2010-01-01

    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

  19. 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

  20. 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…

  1. 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.

  2. 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…

  3. 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…

  4. 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…

  5. 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.

  6. Strange-face illusions during inter-subjective gazing.

    PubMed

    Caputo, Giovanni B

    2013-03-01

    In normal observers, gazing at one's own face in the mirror for a few minutes, at a low illumination level, triggers the perception of strange faces, a new visual illusion that has been named 'strange-face in the mirror'. Individuals see huge distortions of their own faces, but they often see monstrous beings, archetypal faces, faces of relatives and deceased, and animals. In the experiment described here, strange-face illusions were perceived when two individuals, in a dimly lit room, gazed at each other in the face. Inter-subjective gazing compared to mirror-gazing produced a higher number of different strange-faces. Inter-subjective strange-face illusions were always dissociative of the subject's self and supported moderate feeling of their reality, indicating a temporary lost of self-agency. Unconscious synchronization of event-related responses to illusions was found between members in some pairs. Synchrony of illusions may indicate that unconscious response-coordination is caused by the illusion-conjunction of crossed dissociative strange-faces, which are perceived as projections into each other's visual face of reciprocal embodied representations within the pair. Inter-subjective strange-face illusions may be explained by the subject's embodied representations (somaesthetic, kinaesthetic and motor facial pattern) and the other's visual face binding. Unconscious facial mimicry may promote inter-subjective illusion-conjunction, then unconscious joint-action and response-coordination.

  7. 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.

  8. 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.

  9. On the Stability of Strange Dwarf Hybrid Stars

    NASA Astrophysics Data System (ADS)

    Alford, Mark G.; Harris, Steven P.; Sachdeva, Pratik S.

    2017-10-01

    We investigate the stability of “strange dwarfs”: white-dwarf-sized stars with a density discontinuity between a small dense core of quark matter and a thick low-density mantle of degenerate electrons. Previous work on strange dwarfs suggested that such a discontinuity could stabilize stars that would have been classified as unstable by the conventional criteria based on extrema in the mass–radius relation. We investigate the stability of such stars by numerically solving the Sturm–Liouville equations for the lowest-energy modes of the star. We find that the conventional criteria are correct, and strange dwarfs are not stable.

  10. Queen control of a key life-history event in a eusocial insect.

    PubMed

    Holland, Jacob G; Guidat, Florian S; Bourke, Andrew F G

    2013-06-23

    In eusocial insects, inclusive fitness theory predicts potential queen-worker conflict over the timing of events in colony life history. Whether queens or workers control the timing of these events is poorly understood. In the bumble-bee Bombus terrestris, queens exhibit a 'switch point' in which they switch from laying diploid eggs yielding females (workers and new queens) to laying haploid eggs yielding males. By rearing foundress queens whose worker offspring were removed as pupae and sexing their eggs using microsatellite genotyping, we found that queens kept in the complete absence of adult workers still exhibit a switch point. Moreover, the timing of their switch points relative to the start of egg-laying did not differ significantly from that of queens allowed to produce normal colonies. The finding that bumble-bee queens can express the switch point in the absence of workers experimentally demonstrates queen control of a key life-history event in eusocial insects. In addition, we found no evidence that workers affect the timing of the switch point either directly or indirectly via providing cues to queens, suggesting that workers do not fully express their interests in queen-worker conflicts over colony life history.

  11. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  13. Experimental manipulation of queen number affects colony sex ratio investment in the highly polygynous ant Formica exsecta

    PubMed Central

    Kümmerli, Rolf; Helms, Ken R; Keller, Laurent

    2005-01-01

    In polygynous (multiple queens per nest) ants, queen dispersal is often limited with young queens being recruited within the parental colony. This mode of dispersal leads to local resource competition between nestmate queens and is frequently associated with extremely male-biased sex ratios at the population level. The queen-replenishment hypothesis has been recently proposed to explain colony sex ratio investment under such conditions. It predicts that colonies containing many queens (subject to high local resource competition) should only produce males, whereas colonies hosting few queens (reduced or no local resource competition) should produce new queens in addition to males. We experimentally tested this hypothesis in the ant Formica exsecta by manipulating queen number over three consecutive years in 120 colonies of a highly polygynous population. Queens were transferred from 40 colonies into another 40 colonies while queen number was not manipulated in 40 control colonies. Genetic analyses of worker offspring revealed that our treatment significantly changed the number of reproductive queens. The sex ratio of colonies was significantly different between treatments in the third breeding season following the experiment initiation. We found that, as predicted by the queen-replenishment hypothesis, queen removal resulted in a significant increase in the proportion of colonies that produced new queens. These results provide the first experimental evidence for the queen-replenishment hypothesis, which might account for sex ratio specialization in many highly polygynous ant species. PMID:16096090

  14. 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.

  15. 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.

  16. Chiral 2D "strange metals" from SYM

    NASA Astrophysics Data System (ADS)

    Berkooz, Micha; Narayan, Prithvi; Zait, Amir

    2015-01-01

    Familiar field theories may contain closed subsectors made out of only fermions, which can be used to explore new and unusual phases of matter in lower dimensions. We focus on the fermionic su(1, 1) sector in SYM and on its ground states, which are Fermi surface states/operators. By computing their spectrum to order ( g {YM/2} N)2, we argue that fluctuations around this Fermi surface, within the sector and in the limit k F → ∞, are governed by a chiral 1+1 dimensional sector of the "strange metal" coset SU( N ) N ⊗ SU( N ) N /SU( N )2 N . On the gravity side, the conjectured dual configuration is an S = 0 degeneration of a rotating black hole. On general grounds we expect that the near horizon excitations of ( S = 0, Ω = 1, J → ∞) degenerations of black holes will be governed by a chiral sector of a 1+1 CFT.

  17. Strange Stars, Neutron Stars and Pulsar Emission

    NASA Astrophysics Data System (ADS)

    Benvenuto, O. G.; Horvath, J. E.

    1990-11-01

    RESUMEN. Se ha conjeturado que una partlecula de dieciocho quarks, sin Carga, sin espi'n y sin colar (quark-alfa) podri'a ser estable a ba5as tern peraturas y presiones aiTh COfl respecto a materia extrafla. Presentamos en este trabajo la estmctura de estrellas extraflas incluyendo los efectos y apariencia de parti'culas uark-alfa en las capas exteriores. La estruc tura interna ya no es hoinogenea del centro a la superficie, sino que muestra un centro de materia extrafla, capas s6lidas y una costra delgada de materia normal en la superficie. La superficie de materia nonnal permite la fornaci6n de una magnetosfera, la que se piensa sea el sitlo en donde ocurre la emisi6n del pulsar. La superficie de superflui'do ayuda a explicar el fen6rneno de `glitch', el cual ba sido observado en muchos pulsares. Se discute la ecuaci6n de estado para rnateria quark-alfa relevante en este regimen. ABSTIZACT:It has been conjectured that an quark, uncharged, spinless and colorless particle Cquark-alpha) could be stable at low pressures and temperatures even with respect to strange matter. We present in work tlie structure of stars including the effects of the appearance of quark-alpi' particles ii their outer layers. The internal structure is no longer from tlie center to the surface, but show a strange matter core, a solid and superfluid layers and a thin crust of normal matter at the surface. The normal matter surface allows tlie fon tion of a magnetosphere, whicl is to be tl place where pulsar emission occurs. A superfluid layer helps to explain tlie glitch , wlflch has been observed in . equation of state for quark-alpha matter relevant in regime is also discussed. Keq LA)OtL : ARY S - OF STATF - ?.ACT

  18. 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

  19. 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.

  20. 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

  1. Dead Star Warps Light of Red Star Artist Animation

    NASA Image and Video Library

    2013-04-04

    This artist concept depicts an ultra-dense dead star, called a white dwarf, passing in front of a small red star. NASA planet-hunting Kepler was able to detect gravitational lensing by measuring a strangely subtle dip in the star brightness.

  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. Strangeness production in small and large collision systems at RHIC

    NASA Astrophysics Data System (ADS)

    Heinz, Mark T.

    2006-07-01

    We present measurements of strange and multi-strange hadrons in p+p collisions at √s =200 GeV measured by STAR. We will compare these preliminary results to leading-order (LO) and next-to-leading order (NLO) perturbative QCD models widely believed to describe the production mechanisms. In particular we will point out recent changes of the model calculations which improve the agreement with our data significantly and will discuss the physics consequences. In larger collision systems, produced with heavy ions at RHIC, we observe the centrality dependence of strange and multi-strange particle production. The non-linear dependency between (anti)-hyperon yields and the system size Npart seems to indicate that the correlation volume does not scale exactly with Npart in contradiction to previous assumptions by thermal models.

  4. ScienceCast 30: The Strange Attraction of Gale Crater

    NASA Image and Video Library

    2011-09-29

    NASA's newest rover Curiosity is getting ready to leave Earth. It's destination: Gale crater on Mars. Today's story from Science@NASA explains the attraction of this Martian crater with a strangely-sculpted mountain the middle.

  5. Role of strangeness in hybrid stars and possible observables

    NASA Astrophysics Data System (ADS)

    Dexheimer, V.; Negreiros, R.; Schramm, S.

    2015-05-01

    We study the effects of strangeness on the quark sector of a hybrid-star equation of state. Since the model we use to describe quarks is the same as the one we use to describe hadrons, we can also study the effects of strangeness on the chiral symmetry restoration and deconfinement phase transitions (first order or crossover). Finally, we analyze the combined effects of hyperons and quarks on global properties of hybrid stars such as mass, radius, and cooling profiles. It is found that a large amount of strangeness in the core is related to the generation of twin-star solutions, which can have the same mass as the lower or zero strangeness counterpart, but with smaller radii.

  6. Intriguing aspects of strangeness production at CERN energies

    SciTech Connect

    Odyniec, G.

    1996-07-01

    Strange particle production in pp, pA and AA collisions at CERN SPS energies is reviewed. First results from Pb beam experiments are briefly presented. The emerging picture (still incomplete) is discussed.

  7. Strange form factors of octet and decuplet baryons

    SciTech Connect

    Hong, Soon-Tae

    1999-11-22

    The strange form factors of baryon octet are evaluated, in the chiral models with the general chiral SU(3) group structure, to yield the theoretical predictions comparable to the recent experimental data of SAMPLE Collaboration and to study the spin symmetries. Other model predictions are also briefly reviewed to compare with our results and then the strange form factors of baryon octet and decuplet are predicted.

  8. Overview of Issues Surrounding Strangeness in the Nucleon

    SciTech Connect

    Thomas, Anthony W.

    2009-12-17

    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.

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

    SciTech Connect

    Şen, R.; Aygün, S.

    2016-03-25

    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.

  10. 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.

  11. GENERAL: Non-Spherical Gravitational Collapse of Strange Quark Matter

    NASA Astrophysics Data System (ADS)

    S, Zade S.; D, Patil K.; N, Mulkalwar P.

    2008-05-01

    We study the non-spherical gravitational collapse of the strange quark null fluid. The interesting feature which emerges is that the non-spherical collapse of charged strange quark matter leads to a naked singularity whereas the gravitational collapse of neutral quark matter proceeds to form a black hole. We extend the earlier work of Harko and Cheng [Phys. Lett. A 266 (2000) 249] to the non-spherical case.

  12. The baryon spectroscopy: strong decays and strange suppression

    NASA Astrophysics Data System (ADS)

    García-Tecocoatzi, H.

    2017-07-01

    In this contribution, we present the open-flavor strong decays of light baryons computed within the framework of quark model. The transition amplitudes are computed using a modified {3}0P operator, where a mechanism strange suppression is taken into account. Also we discus the strange suppression within an extension of the quark model. Invited talk presented at Symposium on Nuclear Physics, January 4-7 2017, Cocoyoc(Mexico).

  13. 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.

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

    PubMed

    Gilley, David C

    2003-10-07

    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.

  15. Impact of Thiamethoxam on Honey Bee Queen (Apis mellifera carnica) Reproductive Morphology and Physiology.

    PubMed

    Gajger, Ivana Tlak; Sakač, Martina; Gregorc, Aleš

    2017-07-26

    High honey bee losses around the world have been linked in part by the regular use of neonicotinoids in agriculture. In light of the current situation, the aim of this study was to investigate the effects of thiamethoxam on the development of the reproductive system and physiology in the honey bee queen. Two experimental groups of honey bee queen larvae were treated with thiamethoxam during artificial rearing, applied via artificial feed in two cycles. In the first rearing cycle, honey bee larvae received a single treatment dose (4.28 ng thiamethoxam/queen larva on the 4th day after larvae grafting in artificial queen cells), while the second honey bee queen rearing cycle received a double treatment dose (total of 8.56 ng thiamethoxam/queen larva on the 4th and 5th day after larvae grafting in artificial queen cells). After emerging, queens were anesthetized and weighed, and after mating with drones were anesthetized, weighed, and sectioned. Ovary mass and number of stored sperm were determined. Body weight differed between untreated and treated honey bee queens. The results also show a decrease in the number of sperm within honey bee queen spermathecae that received the double thiamethoxam dose.

  16. The Effects of Pesticides on Queen Rearing and Virus Titers in Honey Bees (Apis mellifera L.)

    PubMed Central

    DeGrandi-Hoffman, Gloria; Chen, Yanping; Simonds, Roger

    2013-01-01

    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) colonies were reared in colonies fed pollen-1 or 2 compared with when those larvae were reared in outside colonies. Larvae grafted from and reared in colonies fed pollen-2 had lower rates of queen emergence than pollen-1 or outside colonies. Deformed wing virus (DWV) and black queen cell virus were found in nurse bees from colonies fed pollen-1 or 2 and in outside colonies. The viruses also were detected in queen larvae. However, we did not detect virus in emerged queens grafted from and reared in outside colonies. In contrast, DWV was found in all emerged queens grafted from colonies fed pollen-1 or 2 either reared in outside hives or those fed pollen-1 or 2. The results suggest that sublethal exposure of CPF alone but especially when Pristine® is added reduces queen emergence possibly due to compromised immunity in developing queens. PMID:26466796

  17. No evidence of volatile chemicals regulating reproduction in a multiple queen ant

    NASA Astrophysics Data System (ADS)

    Coston, Duncan J.; Gill, Richard J.; Hammond, Robert L.

    2011-07-01

    Efficient cooperation in eusocial insect colonies requires effective communication, and there is abundant evidence of non-volatile chemicals playing a role in regulating reproduction within colonies. In contrast, there have been fewer studies investigating the role of volatile chemicals. This study investigated the potential role of volatile chemicals in regulating queen reproduction either by directly inhibiting queen reproduction or by honestly signalling queen fecundity to workers. We tested this using multiple queen colonies of the ant ( Leptothorax acervorum) from a functionally monogynous population where one queen monopolizes all reproduction. Nine colonies, each with an established laying queen, were split to produce two colony fragments—one containing the reproducing queen (group 1) and one containing only previously non-reproducing queens (group 2). Each group was separated by a fine wire mesh preventing physical contact, but allowing volatile chemical contact. In each group 2 fragment, we found that a single formerly non-reproductive queen commenced reproduction and that the rate of egg laying and maximum number of eggs recorded did not significantly differ between groups 1 and 2, results that do not support volatile chemicals as playing a role in regulating queen reproduction. Instead, our findings suggest that physical contact is necessary to maintain functional monogyny.

  18. Cuticular hydrocarbons as queen adoption cues in the invasive Argentine ant.

    PubMed

    Vásquez, Gissella M; Schal, Coby; Silverman, Jules

    2008-04-01

    In social insects, individuals typically recognize and behave aggressively towards alien conspecifics, thereby maintaining colony integrity. This is presumably achieved via a nestmate recognition system in which cuticular compounds, usually cuticular hydrocarbons (CHC), of genetic and/or environmental origin serve as recognition cues. Most invasive populations of the Argentine ant, Linepithema humile (Mayr), display minimal nestmate-non-nestmate discrimination, resulting in low levels of intraspecific aggression allowing free movement of workers and queens among nests. However, invasive L. humile in the southeastern United States show relatively high levels of intraspecific aggression, and selectively adopt non-nestmate queens. Using behavioral assays and gas chromatography, we found an association between non-nestmate queen adoption and similarity of the CHC profiles of adopted and host colony queens. Also, nestmate and non-nestmate queen CHC profiles became more similar after adoption by queenless colonies. Furthermore, queens treated with non-nestmate queen CHC had distinct CHC profiles and were generally attacked by nestmate workers. We suggest that in L. humile, CHC are used as queen recognition cues, and that queen recognition errors are more likely to occur when the CHC profiles of non-nestmate and host colony queens are similar. Our findings provide further evidence for the complex and dynamic nature of L. humile nestmate discrimination, which may in part underlie the success of introduced populations of this invasive ant.

  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. Copyright © 2011 Elsevier Inc. All rights reserved.

  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

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

    2012-02-22

    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.

  2. The effects of strong interaction on the observational discrimination between neutron and strange stars

    NASA Astrophysics Data System (ADS)

    Dai, Zi-gao; Lu, Tan

    1995-02-01

    Strange stars are compact objects similar to neutron stars composed of strange matter. This paper investigates the observational effects of the strong interaction between quarks. We believe: 1) that the conversion of a neutron star to a strange star is a large "period glitch" which is determined by the strong interaction; 2) that the strong interaction results in effective damping of oscillation of hot strange stars, which could be a new mechanism of driving supernova explosions; 3) that the strong interaction increases the difference in rotation between strange and neutron stars under high temperatures, making the minimum period for strange stars lower than that for neutron stars.

  3. Strangeness as a probe to baryon-rich QCD matter at NICA

    NASA Astrophysics Data System (ADS)

    Fukushima, Kenji

    2016-08-01

    We elucidate a prospect of strangeness fluctuation measurements in the heavy-ion collision at NICA energies. The strangeness fluctuation is sensitive to quark deconfinement. At the same time strangeness has a strong correlation with the baryon number under the condition of vanishing net strangeness, which leads to an enhancement of Λ0, Ξ0, Ξ-, and K+ at high baryon density. The baryon density is maximized around the NICA energies, and strangeness should be an ideal probe to investigate quark deconfinement phenomena of baryon-rich QCD matter created at NICA. We also utilize the hadron resonance gas model to estimate a mixed fluctuation of strangeness and baryon number.

  4. Deep Seismic Reflection Imaging of the Queen Charlotte Basin

    NASA Astrophysics Data System (ADS)

    Calvert, A. J.

    2009-05-01

    A deep 2-D seismic reflection survey was shot by the Geological Survey of Canada in Hecate Strait and Queen Charlotte Sound in 1988 using a 45 m shot point interval, 15 m group interval and a maximum offset of 3685 m. Subsequent analysis of these data has focused on the shallower section, and helped constrain, together with earlier industry data, the general evolution of the sedimentary section. North-trending sub-basins are found to the south in Queen Charlotte Sound, but relatively closely-spaced NW-trending sub-basins predominate further north in Hecate Strait. Previous interpretation has demonstrated transtensional tectonics during most of the Miocene with evidence for transpression and inversion of some normal faults in Hecate Strait during the Pliocene. Although a range of origins including hot spot rifting have been suggested for the Queen Charlotte basin, currently favoured explanations focus on the effects of, and changes in, large-scale plate motions in this region. To determine if the deeper sections of the 1988 seismic survey can further constrain models of basin evolution, these seismic data have been reprocessed to 14 s. A thick sequence of subhorizontal reflectors, which extend from 4.5-8.5 s, is identified beneath northern Hecate Strait where rocks of the Alexander terrane are identified at the surface. Further south, discrete 0.5-1.0 s thick reflection packages, some of which may be intrusive in origin, are identified in the mid and lower crust of the Wrangellia terrane. Other reflections occur as deep as 10-11 s beneath the central axis of the basin in Hecate Strait, which could locate them beneath the Moho inferred from wide-angle surveys. Deep seismic imaging is more limited beneath southern Hecate Strait and northern Queen Charlotte Sound, perhaps due to the effects of coherent noise, but reflections can be identified at 6-8 s beneath southern Queen Charlotte Sound. Marine surveys are often degraded by water layer multiples and coherent

  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. 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.

  8. 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.

  9. The origin and evolution of social insect queen pheromones: Novel hypotheses and outstanding problems.

    PubMed

    Oi, Cintia A; van Zweden, Jelle S; Oliveira, Ricardo C; Van Oystaeyen, Annette; Nascimento, Fabio S; Wenseleers, Tom

    2015-07-01

    Queen pheromones, which signal the presence of a fertile queen and induce daughter workers to remain sterile, are considered to play a key role in regulating the reproductive division of labor of insect societies. Although queen pheromones were long thought to be highly taxon-specific, recent studies have shown that structurally related long-chain hydrocarbons act as conserved queen signals across several independently evolved lineages of social insects. These results imply that social insect queen pheromones are very ancient and likely derived from an ancestral signalling system that was already present in their common solitary ancestors. Based on these new insights, we here review the literature and speculate on what signal precursors social insect queen pheromones may have evolved from. Furthermore, we provide compelling evidence that these pheromones should best be seen as honest signals of fertility as opposed to suppressive agents that chemically sterilize the workers against their own best interests. © 2015 WILEY Periodicals, Inc.

  10. Atmospheric neutrinos can make beauty strange

    NASA Astrophysics Data System (ADS)

    Harnik, Roni; Larson, Daniel T.; Murayama, Hitoshi; Pierce, Aaron

    2004-05-01

    The large observed mixing angle in atmospheric neutrinos, coupled with grand unification, motivates the search for large mixing between right-handed strange and bottom squarks. Such mixing does not appear in the standard Cabibbo-Kobayashi-Maskawa phenomenology, but may induce significant b→s transitions through gluino diagrams. Working in the mass eigenbasis, we show quantitatively that an O(1) effect on CP violation in B0d→φKS is possible due to a large mixing between sR and bR, while still satisfying constraints from b→sγ. We also include the effect of bL-bR mixing proportional to mbμ tan β. In the case where mbμ tan β≪M2SUSY there may be a large effect in Bs mixing correlated with a large effect in B0d→φKS, typically yielding an unambiguous signal of new physics at Tevatron run II.

  11. The Strange World of Classical Physics

    NASA Astrophysics Data System (ADS)

    Green, David

    2010-02-01

    We have heard many times that the commonsense world of classical physics was shattered by Einstein's revelation of the laws of relativity. This is certainly true; the shift from our everyday notions of time and space to those revealed by relativity is one of the greatest stretches the mind can make. What is seldom appreciated is that the laws of classical physics yield equally strange (or arguably even stranger) results if the observer happens to be in a very high velocity reference frame. This article addresses two questions: In Part I we examine what the world would look like if relativity was not in effect and you happened to be in a reference frame traveling at a high percentage of the speed of light or faster than light (perfectly allowable in this model), a conceptual world that existed on a foundation of Newtonian physics and the aether. It turns out that this is a weirder place than is generally realized. In Part II we see that classical physics in these frames is self-contradictory. Neither the consideration of Maxwell's equations nor the Michelson-Morley experiment is necessary to see these contradictions; they are implicit in the logic of the physics itself.

  12. Strangeness Prospects with the CBM Experiment

    NASA Astrophysics Data System (ADS)

    Friese, Volker

    2016-01-01

    The CBM experiment will study strongly interacting matter at high net-baryon densities with nuclear collisions up to 45A GeV beam energy at the future FAIR facility. With interaction rates unprecedented in heavy-ion collisions, CBM will give access also to extremely rare probes and thus to the early stage of the collisions, in search for the first-order phase transition from confined to deconfined matter and the QCD critical point. The CBM physics programme will be started with beams delivered by the SIS-100 synchrotron, providing energies from 2 to 11 GeV/nucleon for heavy nuclei, up to 14 GeV/nucleon for light nuclei, and 30 GeV for protons. The highest net baryon densities will be explored with ion beams up to 45 GeV/nucleon energy delivered by SIS-300 in a later stage of the FAIR project. After several years of preparation, the CBM experiment now enters the realisation phase. In this article, we report on the current status of the system developments and the expected physics performance for strange and charmed observables, as well as on the roadmap towards the first data taking.

  13. New results on mesons containing strange quarks

    SciTech Connect

    Aston, D.; Awaji, N.; Bienz, T.; Bird, F.; D'Amore, J.; Dunwoodie, W.; Endorf, R.; Fujii, K.; Hayashii, H.; Iwata, S.

    1987-01-01

    Recent results of strange and strangeonium mesons are presented. The data come from a high sensitivity study (4.1 ev/nb) of K/sup -/p interactions at 11 GeV/c using the LASS spectrometer at SLAC. The complete leading orbitally-excited K* series up through J/sup P/ = 5/sup -/ and a substantial number of the expected underlying states are observed decaying into K/sup -/..pi../sup +/, anti K/sub 3//sup 0/..pi../sup +/..pi../sup -/, and K eta final states, and new measurements are made of their masses, widths, and branching ratios. Production of strangeonium states via hypercharge exchange is observed into K/sub 3//sup 0/K/sub 3//sup 0/, K/sup -/K/sup +/, and K/sub 3//sup 0/K/sup + -/..pi../sup - +/ final states. The leading orbitally-excited phi series through J/sup P/ = 3/sup -/ is clearly seen and evidence is presented for additional high spin structure in the 2.2 GeV/c/sup 2/ region. No f/sub 2/(1720) is observed. The K/sub 3//sup 0/K/sup + -/..pi../sup - +/ spectrum is dominated by 1/sup +/(K* anti K + anti K* K) production in the region below 1.6 GeV/c/sup 2/. These results are compared with data on the same systems produced by different production mechanisms. 12 refs., 28 figs.

  14. Atmospheric neutrinos can make beauty strange

    SciTech Connect

    Harnik, Roni; Larson, Daniel T.; Murayama, Hitoshi; Pierce, Aaron

    2002-12-01

    The large observed mixing angle in atmospheric neutrinos, coupled with Grand Unification, motivates the search for a large mixing between right-handed strange and bottom squarks. Such mixing does not appear in the standard CKM phenomenology, but may induce significant b {yields} s transitions through gluino diagrams. Working in the mass eigenbasis, we show quantitatively that an order one effect on CP violation in B{sub d}{sup 0} {yields} {pi}K{sub S} is possible due to a large mixing between right-handed b and s squarks, while still satisfying constraints from b {yields} s {gamma}. We also include the effect of right- and left-handed bottom squark mixing proportional to m{sub b}{mu} tan{beta}. For small {mu}tan{beta} there may also be a large effect in B{sub s} mixing correlated with a large effect in B{sub d}{sup 0} {yields} {phi}K{sub S}, typically yielding an unambiguous signal of new physics at Tevatron Run II.

  15. 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.

  16. 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 exhibition...

  17. Queen control of a key life-history event in a eusocial insect

    PubMed Central

    Holland, Jacob G.; Guidat, Florian S.; Bourke, Andrew F. G.

    2013-01-01

    In eusocial insects, inclusive fitness theory predicts potential queen–worker conflict over the timing of events in colony life history. Whether queens or workers control the timing of these events is poorly understood. In the bumble-bee Bombus terrestris, queens exhibit a ‘switch point’ in which they switch from laying diploid eggs yielding females (workers and new queens) to laying haploid eggs yielding males. By rearing foundress queens whose worker offspring were removed as pupae and sexing their eggs using microsatellite genotyping, we found that queens kept in the complete absence of adult workers still exhibit a switch point. Moreover, the timing of their switch points relative to the start of egg-laying did not differ significantly from that of queens allowed to produce normal colonies. The finding that bumble-bee queens can express the switch point in the absence of workers experimentally demonstrates queen control of a key life-history event in eusocial insects. In addition, we found no evidence that workers affect the timing of the switch point either directly or indirectly via providing cues to queens, suggesting that workers do not fully express their interests in queen–worker conflicts over colony life history. PMID:23637392

  18. 76 FR 2438 - Culturally Significant Objects Imported for Exhibition Determinations: “Kings, Queens, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-13

    ... Early Renaissance France'' SUMMARY: Notice is hereby given of the following determinations: Pursuant to... the exhibition ``Kings, Queens, and Courtiers: Art in Early Renaissance France'' imported from...

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

    PubMed

    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.

  20. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Strange Bedfellows; Physical and Biological Oceanographers

    NASA Astrophysics Data System (ADS)

    Wooster, W. S.

    2002-12-01

    understanding the response of marine ecosystems to environmental forcing cannot be achieved without the effective collaboration of these strange bedfellows.

  2. Geology of the De Queen and Caddo Gap quadrangles, Arkansas

    USGS Publications Warehouse

    Miser, Hugh D.; Purdue, Albert Homer

    1929-01-01

    The field study of the geology of the De Queen and Caddo Gap quadrangles extended over a period of many years, and although the scientific and economic results from the study are here set forth fully for the first time in a single report, a number of publications have been issued that have presented some of the more important results.The field work was begun in 1907 and continued intermittently until 1925. The work in 1907 was done under a cooperative agreement between the United States Geological Survey and the Arkansas Geological Survey and involved primarily an investigation of the slate deposits of west-central Arkansas but also the mapping of the rocks in the mountainous part of the Caddo Gap quadrangle. In that year A. H. Purdue, State geologist of Arkansas, had charge of the work and was assisted by R. D. Mesler and H. D. Miser. All the subsequent work in the Caddo Gap quadrangle, as well as all in the De Queen quadrangle, was done by the United States Geological Survey. The work since 1907 is briefly outlined below. In 1908 Mr. Purdue, assisted by Mr. Miser, completed the mapping of the rocks of the Caddo Gap quadrangle with the aid of valuable suggestions from C. W. Hayes, chief geologist, J. A. Taff, and E. O. Ulrich, who visited the field for several days. In 1910 Mr. Purdue, assisted by Mr. Miser, reviewed a part of the previous work in the Caddo Gap quadrangle and mapped the rocks in most of the mountainous portion of the De Queen quadrangle. In 1911 these geologists did additional work in both the De Queen and Caddo Gap quadrangles, and in 1912 Mr. Miser, assisted by Mr. Mesler, completed the mapping of the rocks in the De Queen quadrangle and then reviewed some of the earlier work in the Caddo Gap quadrangle. In 1913 Arthur Keith, and Messrs. Purdue and Miser spent several days in a field conference in the Caddo Gap quadrangle. During the conference the first identifiable fossils in the Blaylock sandstone, of Silurian age, were discovered. In 1914 Mr

  3. Strangeness production in Si + Au interactions at 14. 6 GeV/c per nucleon

    SciTech Connect

    Hansen, O.

    1989-01-01

    Production of strange particles in proton-proton interactions is systematically suppressed relative to the production of non-strange particles. A first order goal of experiments on strangeness production in nucleus-nucleus collisions is to find out if strangeness is suppressed in a way similar to the p-p interactions or whether the nuclear environment changes the behaviour. This paper investigates this possibility. 13 refs., 1 tab.

  4. COALESCENCE OF STRANGE-QUARK PLANETS WITH STRANGE STARS: A NEW KIND OF SOURCE FOR GRAVITATIONAL WAVE BURSTS

    SciTech Connect

    Geng, J. J.; Huang, Y. F.; Lu, T.

    2015-05-01

    Strange-quark matter (SQM) may be the true ground state of hadronic matter, indicating that the observed pulsars may actually be strange stars (SSs), but not neutron stars. According to the SQM hypothesis, the existence of a hydrostatically stable sequence of SQM stars has been predicted, ranging from 1 to 2 solar mass SSs, to smaller strange dwarfs and even strange planets. While gravitational wave (GW) astronomy is expected to open a new window to the universe, it will shed light on the search for SQM stars. Here we show that due to their extreme compactness, strange planets can spiral very close to their host SSs without being tidally disrupted. Like inspiraling neutron stars or black holes, these systems would serve as new sources of GW bursts, producing strong GWs at the final stage. The events occurring in our local universe can be detected by upcoming GW detectors, such as Advanced LIGO and the Einstein Telescope. This effect provides a unique probe to SQM objects and is hopefully a powerful tool for testing the SQM hypothesis.

  5. Coalescence of Strange-quark Planets with Strange Stars: a New Kind of Source for Gravitational Wave Bursts

    NASA Astrophysics Data System (ADS)

    Geng, J. J.; Huang, Y. F.; Lu, T.

    2015-05-01

    Strange-quark matter (SQM) may be the true ground state of hadronic matter, indicating that the observed pulsars may actually be strange stars (SSs), but not neutron stars. According to the SQM hypothesis, the existence of a hydrostatically stable sequence of SQM stars has been predicted, ranging from 1 to 2 solar mass SSs, to smaller strange dwarfs and even strange planets. While gravitational wave (GW) astronomy is expected to open a new window to the universe, it will shed light on the search for SQM stars. Here we show that due to their extreme compactness, strange planets can spiral very close to their host SSs without being tidally disrupted. Like inspiraling neutron stars or black holes, these systems would serve as new sources of GW bursts, producing strong GWs at the final stage. The events occurring in our local universe can be detected by upcoming GW detectors, such as Advanced LIGO and the Einstein Telescope. This effect provides a unique probe to SQM objects and is hopefully a powerful tool for testing the SQM hypothesis.

  6. Toxicity of cryoprotectants to honey bee semen and queens.

    PubMed

    Wegener, J; Bienefeld, K

    2012-02-01

    Given the threats to the intraspecific biodiversity of Apis mellifera and the pressure on bee breeding to come up with disease-tolerant lines, techniques to cryopreserve drone semen are of great interest. Freeze-thawed drone semen of high viability and/or motility has repeatedly been obtained, but fertility of such semen, when it was measured, was always low. The cryoprotective agent (CPA) most frequently used with drone semen is dimethyl sulfoxide (DMSO), although this substance has been suspected of causing genetic damage in sperm. No form of sperm washing is currently performed. Using a membrane permeability assay, we measured the short-term toxicity of four possible replacements for DMSO, 1,3-propane diol, 2,3-butane diol, ethylene glycol, and dimethyl formamide. We also tested whether the practice of inseminating queens with CPA-containing semen affects sperm numbers in the storage organs of queens, or sperm fertility. Finally, we tested whether CPA-toxicity in vivo can be reduced by using mixtures of two CPAs, DMSO, and ethylene glycol. Our results show that, although short-term toxicity of all CPAs tested was low, the presence of single CPAs in insemination mixtures at concentrations required for slow freezing greatly reduced the number of sperm reaching the spermatheca. Contrary to earlier reports, this was also true for DMSO. Ethylene glycol was additionally shown to reduce the viability of spermatozoa reaching the storage organ. Mixtures of DMSO and EthGly performed better than either substance used singly at the same concentration. We conclude that the toxicity of CPAs, including DMSO, on honey bee semen and/or queens has been underestimated in the past. This could partly explain the discrepancy between in vitro and in vivo quality of cryopreserved drone semen, described by others. Combinations of several CPAs and techniques to partly remove CPAs after thawing could help to solve this problem. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Strange quark condensate from QCD sum rules to five loops

    NASA Astrophysics Data System (ADS)

    Dominguez, Cesareo A.; Nasrallah, Nasrallah F.; Schilcher, Karl

    2008-02-01

    It is argued that it is valid to use QCD sum rules to determine the scalar and pseudoscalar two-point functions at zero momentum, which in turn determine the ratio of the strange to non-strange quark condensates Rsu = langlebar ssrangle/langlebar qqrangle with (q = u, d). This is done in the framework of a new set of QCD Finite Energy Sum Rules (FESR) that involve as integration kernel a second degree polynomial, tuned to reduce considerably the systematic uncertainties in the hadronic spectral functions. As a result, the parameters limiting the precision of this determination are ΛQCD, and to a major extent the strange quark mass. From the positivity of Rsu there follows an upper bound on the latter: \\overline{ms}(2 GeV) <= 121 (105) MeV, for ΛQCD = 330 (420) MeV.

  8. The strange flight behaviour of slowly spinning soccer balls

    NASA Astrophysics Data System (ADS)

    Mizota, Taketo; Kurogi, Kouhei; Ohya, Yuji; Okajima, Atsushi; Naruo, Takeshi; Kawamura, Yoshiyuki

    2013-05-01

    The strange three-dimensional flight behaviour of slowly spinning soccer balls is one of the most interesting and unknown phenomenon associated with the trajectories of sports balls. Many spectators have experienced numerous exciting and emotional instances while observing the curious flight behaviour of these balls. We examine the aerodynamic mechanisms of erratic ball behaviours through real flight observations, unsteady force measurements and flow pattern visualisations. The strange behaviour is elucidated by the relationship between the unsteady forces on the ball and the wake flow. The irregular changes in position for twin longitudinal vortices have already been discovered in the supercritical Reynolds number region of a sphere with a smooth surface. This finding is applicable to the strange behaviour of the flight of soccer balls with this supercritical flow. The players, spectators, and television viewers will gain greater insight into the effects of soccer ball flights.

  9. The strange flight behaviour of slowly spinning soccer balls

    PubMed Central

    Mizota, Taketo; Kurogi, Kouhei; Ohya, Yuji; Okajima, Atsushi; Naruo, Takeshi; Kawamura, Yoshiyuki

    2013-01-01

    The strange three-dimensional flight behaviour of slowly spinning soccer balls is one of the most interesting and unknown phenomenon associated with the trajectories of sports balls. Many spectators have experienced numerous exciting and emotional instances while observing the curious flight behaviour of these balls. We examine the aerodynamic mechanisms of erratic ball behaviours through real flight observations, unsteady force measurements and flow pattern visualisations. The strange behaviour is elucidated by the relationship between the unsteady forces on the ball and the wake flow. The irregular changes in position for twin longitudinal vortices have already been discovered in the supercritical Reynolds number region of a sphere with a smooth surface. This finding is applicable to the strange behaviour of the flight of soccer balls with this supercritical flow. The players, spectators, and television viewers will gain greater insight into the effects of soccer ball flights. PMID:23695000

  10. AINSWORTH'S STRANGE SITUATION PROCEDURE: THE ORIGIN OF AN INSTRUMENT.

    PubMed

    Van Rosmalen, Lenny; Van der Veer, René; Van der Horst, Frank

    2015-01-01

    The American-Canadian psychologist Mary Ainsworth (1913-1999) developed the Strange Situation Procedure (SSP) to measure mother-child attachment and attachment theorists have used it ever since. When Ainsworth published the first results of the SSP in 1969, it seemed a completely novel and unique instrument. However, in this paper we will show that the SSP had many precursors and that the road to such an instrument was long and winding. Our analysis of hitherto little-known studies on children in strange situations allowed us to compare these earlier attempts with the SSP. We argue that it was the combination of Ainsworth's working experience with William Blatz and John Bowlby, her own research in Uganda and Baltimore, and the strong connection of the SSP with attachment theory, that made the SSP differ enough from the other strange situation studies to become one of the most widely used instruments in developmental psychology today. © 2015 Wiley Periodicals, Inc.

  11. Thermal evolution and light curves of young bare strange stars.

    PubMed

    Page, Dany; Usov, Vladimir V

    2002-09-23

    We study numerically the cooling of a young bare strange star and show that its thermal luminosity, mostly due to e(+)e(-) pair production from the quark surface, may be much higher than the Eddington limit. The mean energy of photons far from the strange star is approximately 10(2) keV or even more. This differs both qualitatively and quantitatively from the thermal emission from neutron stars and provides a definite observational signature for bare strange stars. It is shown that the energy gap of superconducting quark matter may be estimated from the light curves if it is in the range from approximately 0.5 MeV to a few MeV.

  12. A meson cloud model of strangeness asymmetry in the proton

    NASA Astrophysics Data System (ADS)

    Netzel, Greg; Raschko, David; Hansen, Chase

    2013-10-01

    We use a meson cloud model to describe strangeness in the proton. In this model the proton can fluctuate into meson-baryon pairs, as allowed by the Heisenberg uncertainty principle. The leading contributions to strangeness are from the meson-baryon pairs K Λ or K Σ. In this model, the probability of finding strange quark pairs depends on both the splitting functions, which represent the probability of splitting into a given meson-baryon state, and the phenomenological vertex form factors. Because the s and {s} quarks reside in different hadrons, their momentum distributions will differ, as suggested by the NuTeV anomaly and recent global parton distribution fits. We compare our results to other theoretical calculations and to experimental data from HERMES and ATLAS, and to global parton distribution fits. Supported in part by NSF Grants No. 0855656 and 1205686.

  13. Studies of the Strange Sea-Quarks Spin with Kaons

    NASA Astrophysics Data System (ADS)

    Benmokhtar, Fatiha; Voloshin, Andrew; Goodwill, Justin; Lendacky, Andrew

    2017-01-01

    It is well known that quarks and gluons give the substructure to the nucleons. and understanding of the spin structure of the nucleon in terms of quarks and gluons has been the goal of intense investigations during the last decades. The determination of strangeness is challenging and the only way of determining the strange distribution accurately from data is to improve the semi-inclusive information. This talk is focused on the determination of the strange sea contribution to the nucleon spin through the pseudo-scalar method using semi-inclusive Kaon detection technique with CLAS12 at Jefferson Lab. A Ring Imaging CHerenkov (RICH) detector is under construction and will be used for pion-kaon-proton separation. National Science Foundation #1615067.

  14. Plasticity in queen number and social structure in the invasive Argentine ant (Linepithema humile).

    PubMed

    Ingram, Krista K

    2002-10-01

    In many polygynous social insect societies, ecological factors such as habitat saturation promote high queen numbers by increasing the cost of solitary breeding. If polygyny is associated with constrained environments, queen number in colonies of invasive social insects should increase as saturation of their new habitat increases. Here I describe the variation in queen number, nestmate relatedness, and nest size along a gradient of time since colonization in an invading population of Argentine ants (Linepithema humile) in Haleakala, Hawaii. Nest densities in this population increase with distance from the leading edge of the invasion, reaching a stable density plateau approximately 80 m from the edge (> 2 years after colonization). Although the number of queens per nest in Haleakala is generally lower than previously reported for Argentine ants, there is significant variation in queen number across this population. Both the observed and effective queen numbers increase across the density gradient, and nests in the center of the population contain queen numbers three to nine times higher than those on the edge of the invasion. The number of workers per nest is correlated with queen number, and nests in the center are six times larger than nests at the edge. Microsatellite analysis of relatedness among nestmates reveals that all nests in the Haleakala population are characterized by low relatedness and have evidence of multiple reproducing queens. Relatedness values are significantly lower in nests in the center of the population, indicating that the number of reproducing queens is greater in areas of high nest density. The variation in queen number and nestmate relatedness in this study is consistent with expectations based on changes in ecological constraints during the invasion of a new habitat, suggesting that the social structure of Argentine ant populations is strongly influenced by ecological factors. Flexibility in social structure may facilitate persistence

  15. The facial reconstruction of an Ancient Egyptian Queen.

    PubMed

    Manley, Bill; Eremin, Katherine; Shortland, Andrew; Wilkinson, Caroline

    2002-12-01

    The National Museums of Scotland Mummy Project has provided important new information about a burial excavated in Egypt. This has resulted in the facial reconstruction of a woman who was probably a queen at Thebes ca. 1570-1520 BCE. There are strong suggestions from the grave goods and her diet that this woman may have been ethnically Nubian rather than Egyptian. However, it is not yet possible to establish her ethnic identity for sure, so a definitive reconstruction of her appearance in life remains elusive.

  16. Queen Cleopatra and the other 'Cleopatras': their medical legacy.

    PubMed

    Tsoucalas, Gregory; Kousoulis, Antonis A; Poulakou-Rebelakou, Effie; Karamanou, Marianna; Papagrigoriou-Theodoridou, Maria; Androutsos, George

    2014-05-01

    Cleopatra is a female figure widespread in Greece (especially in Macedonian territory), Egypt and Syria during the Hellenistic era. Ancient women doctors bearing the name Cleopatra have been identified by a systematic search through the ancient Greek, Latin and Egyptian bibliography, including original resources from the first century BC. Fictional and non-fictional figures have been distinguished and their works identified. Queen Cleopatra of Egypt, Galen's physician assistant, the outcast Metrodora, Cleopatra the Alchemist and Cleopatra the Gynaecologist deliver a story of medicine and name-giving that confuses researchers of the past and intrigues those of the present.

  17. Gertrude Stein, opium queen: notes on a mistaken embrace.

    PubMed

    Solomon, Jeff

    2013-01-01

    Gertrude Stein was not only a fairly open lesbian but also Jewish, expatriate, and androgynous-all attributes that often retarded mass-market success. Why then was she so popular? The article offers original research highlighting how Stein was constructed as a kind of "opium queen" in the popular American press, and the ways that this decadent, bohemian celebrity persona allowed her to operate as "broadly queer" rather than "specifically gay" in the American cultural imaginary-a negotiation that accounts for the mass-market success rather than censure of The Autobiography of Alice B. Toklas despite the unparalleled visibility of its lesbian erotics.

  18. Chiral extrapolations on the lattice with strange sea quarks

    NASA Astrophysics Data System (ADS)

    Descotes-Genon, Sébastien

    2005-06-01

    The (light but not-so-light) strange quark may play a special role in the low-energy dynamics of QCD. Strange sea-quark pairs may induce significant differences in the pattern of chiral symmetry breaking in the chiral limits of two and three massless flavours, in relation with the violation of the Zweig rule in the scalar sector. This effect could affect chiral extrapolations of unquenched lattice simulations with three dynamical flavours, and it could be detected through the quark-mass dependence of hadron observables [S. Descotes-Genon, hep-ph/0410233].

  19. A strange horn between Paolo Mantegazza and Charles Darwin.

    PubMed

    Garbarino, Carla; Mazzarello, Paolo

    2013-09-01

    During the preparation of an exhibition in Pavia dedicated to the centennial anniversary of the death of the Italian Pathologist Paolo Mantegazza, a strange cheratinic horn was found at the Museum for the History of the University of Pavia labelled as 'spur of a cock transplanted into an ear of a cow.' After some historical investigation, we found this strange object was at the centre of a scientific correspondence between Mantegazza and Charles Darwin, who made reference to it in his book The Variation of Animals and Plants under Domestication.

  20. Calculation of the strange quark mass using domain wall fermions

    SciTech Connect

    Blum, Tom; Soni, Amarjit; Wingate, Matthew

    1999-12-01

    We present a first calculation of the strange quark mass using domain wall fermions. This paper contains an overview of the domain wall discretization and a pedagogical presentation of the perturbative calculation necessary for computing the mass renormalization. We combine the latter with numerical simulations to estimate the strange quark mass. Our final result in the quenched approximation is 95(26) MeV in the MS scheme at a scale of 2 GeV. We find that domain wall fermions have a small perturbative mass renormalization, similar to Wilson quarks, and exhibit good scaling behavior. (c) 1999 The American Physical Society.

  1. Effect of hyperons on phase coexistence in strange matter

    NASA Astrophysics Data System (ADS)

    Das, P.; Mallik, S.; Chaudhuri, G.

    2017-01-01

    The study of the liquid gas phase transition in the fragmentation of nuclei in heavy ion collisions has been extended to the strangeness sector using the statistical model for multifragmentation. Helmholtz's free energy, specific heat, and a few other thermodynamic observables have been analyzed in order to examine the occurrence of phase transition in the strange matter. The bimodal behavior of the largest cluster formed in fragmentation also strongly indicates a coexistence of both the phases. The presence of hyperons strengthens the signals and also shifts the transition temperature to lower values.

  2. Strange magnetism and the anapole structure of the proton.

    SciTech Connect

    Hasty, R.; Hawthorne-Allen, A. M.; Averett, T.; Barkhuff, D.; Beck, D. H.; Mueller, B.; SAMPLE Collaboration; Physics; Univ. of Illinois; Virginia Polytechnic Inst. and State Univ.; Coll. of William and Mary; Lab. for Nuclear Science and Department of Physics

    2000-12-15

    The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium.

  3. Summary of recent experimental results on strangeness production

    NASA Astrophysics Data System (ADS)

    Kalweit, Alexander

    2017-01-01

    This article summarises the highlights of the recent experimental findings on strangeness production presented at the 16th edition of the International Conference on Strangeness in Quark Matter in Berkeley. Results obtained by eight large experimental collaborations (ALICE, ATLAS, CMS, HADES, LHCb, NA-61, PHENIX, STAR) spanning a large range in centre-of-mass energy and a variety of collision systems were presented at the conference. The article does not aim at being a complete review, but rather at connecting the experimental highlights of the different collaborations and at pointing towards questions which should be addressed by these experiments in future.

  4. Using the Moon as a Strange Quark Nugget Detector

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

    We review the romance and mystery of strange quark matter (SQM), including: its basics, our recent work on bounds on the abundance of ton-range strange quark nuggets (SQNs) from Earth seismology, potential SQN bounds from a possible seismic search on the Moon, and our recent bounds on SQNs in the 10 kilogram to ton range from the data of Apollo-implanted seismometers. Finally, we speculate a bit on using the sun or the solar system to detect passage of SQNs of much greater mass than the aforementioned.

  5. Dark matter, neutron stars, and strange quark matter.

    PubMed

    Perez-Garcia, M Angeles; Silk, Joseph; Stone, Jirina R

    2010-10-01

    We show that self-annihilating weakly interacting massive particle (WIMP) dark matter accreted onto neutron stars may provide a mechanism to seed compact objects with long-lived lumps of strange quark matter, or strangelets, for WIMP masses above a few GeV. This effect may trigger a conversion of most of the star into a strange star. We use an energy estimate for the long-lived strangelet based on the Fermi-gas model combined with the MIT bag model to set a new limit on the possible values of the WIMP mass that can be especially relevant for subdominant species of massive neutralinos.

  6. Strange metal transport realized by gauge/gravity duality.

    PubMed

    Faulkner, Thomas; Iqbal, Nabil; Liu, Hong; McGreevy, John; Vegh, David

    2010-08-27

    Fermi liquid theory explains the thermodynamic and transport properties of most metals. The so-called non-Fermi liquids deviate from these expectations and include exotic systems such as the strange metal phase of cuprate superconductors and heavy fermion materials near a quantum phase transition. We used the anti-de-Sitter/conformal field theory correspondence to identify a class of non-Fermi liquids; their low-energy behavior is found to be governed by a nontrivial infrared fixed point, which exhibits nonanalytic scaling behavior only in the time direction. For some representatives of this class, the resistivity has a linear temperature dependence, as is the case for strange metals.

  7. Statistical properties of chaotic dynamical systems which exhibit strange attractors

    SciTech Connect

    Jensen, R.V.; Oberman, C.R.

    1981-07-01

    A path integral method is developed for the calculation of the statistical properties of turbulent dynamical systems. The method is applicable to conservative systems which exhibit a transition to stochasticity as well as dissipative systems which exhibit strange attractors. A specific dissipative mapping is considered in detail which models the dynamics of a Brownian particle in a wave field with a broad frequency spectrum. Results are presented for the low order statistical moments for three turbulent regimes which exhibit strange attractors corresponding to strong, intermediate, and weak collisional damping.

  8. Baryon number and strangeness: signals of a deconfinedantecedent

    SciTech Connect

    Majumder, A.; Koch, V.; Randrup, J.

    2005-06-29

    The correlation between baryon number and strangeness is used to discern the nature of the deconfined matter produced at vanishing chemical potential in high-energy nuclear collisions at the BNL RHIC. Comparisons of results of various phenomenological models with correlations extracted from lattice QCD calculations suggest that a quasi-particle picture applies. At finite baryon densities, such as those encountered at the CERN SPS, it is demonstrated that the presence of a first-order phase transition and the accompanying development of spinodal decomposition would significantly enhance the number of strangeness carriers and the associated fluctuations.

  9. Ratio of strange to non-strange quark condensates in QCD

    NASA Astrophysics Data System (ADS)

    Dominguez, C. A.; Ramlakan, A.; Schilcher, K.

    2001-06-01

    Laplace transform QCD sum rules for two-point functions related to the strangeness-changing scalar and pseudoscalar Green's functions ψ(Q2) and ψ5(Q2), are used to determine the subtraction constants /ψ(0) and ψ5(0), which fix the ratio Rsu≡/<ūu>. Our results are ψ(0)=-(1.06+/-0.21)×10-3 GeV4, ψ5(0)=(3.35+/-0.25)×10-3 GeV4, and Rsu≡/<ūu>=0.5+/-0.1. This implies corrections to kaon-PCAC at the level of /50%, which although large, are not inconsistent with the size of the corrections to Goldberger-Treiman relations in /SU(3)⊗SU(3).

  10. Chemical profiles of mated and virgin queens, egg-laying intermorphs and workers of the ant Crematogaster smithi.

    PubMed

    Oettler, Jan; Schmitt, Thomas; Herzner, Gudrun; Heinze, Jürgen

    2008-04-01

    Many colonies of the North American ant Crematogaster smithi contain a "third female caste" in addition to queens and workers. These "intermorphs" are morphological intermediate of queens and workers and have well-developed ovaries but lack a spermatheca for the storage of sperm. They are specialised for laying large numbers of unfertilised, viable eggs, most of which serve as food for larvae and adults, though a few may eventually develop into males. Based on the assumption that cuticular hydrocarbons (CHCs) in social insects honestly signal the reproductive status of an individual we investigated the CHC of mated mature queens, virgin queens, intermorphs and workers. We expected intermorphs to show chemical profiles intermediate between those of mated queens and non-reproductive workers. A discriminant analysis of the chemical profiles reliably separated queens, virgin queens, and workers, but failed to distinguish between queens and intermorphs even though workers were apparently capable of doing so.

  11. Workers and alate queens of Solenopsis geminata share qualitatively similar but quantitatively different venom alkaloid chemistry

    USDA-ARS?s Scientific Manuscript database

    The cis and trans alkaloids from body extracts of workers and alate queens of the tropical fire ant, Solenopsis geminata (Hymenoptera: Formicidae), were successfully separated by silica gel chromatography, identified, and quantitated by GC-MS analysis. Both workers and alate queens produce primarily...

  12. Killing and replacing queen-laid eggs: low cost of worker policing in the honeybee.

    PubMed

    Kärcher, Martin H; Ratnieks, Francis L W

    2014-07-01

    Worker honeybees, Apis mellifera, police each other's reproduction by killing worker-laid eggs. Previous experiments demonstrated that worker policing is effective, killing most (∼98%) worker-laid eggs. However, many queen-laid eggs were also killed (∼50%) suggesting that effective policing may have high costs. In these previous experiments, eggs were transferred using forceps into test cells, mostly into unrelated discriminator colonies. We measured both the survival of unmanipulated queen-laid eggs and the proportion of removal errors that were rectified by the queen laying a new egg. Across 2 days of the 3-day egg stage, only 9.6% of the queen-laid eggs in drone cells and 4.1% in worker cells were removed in error. When queen-laid eggs were removed from cells, 85% from drone cells and 61% from worker cells were replaced within 3 days. Worker policing in the honeybee has a high benefit to policing workers because workers are more related to the queen's sons (brothers, r = 0.25) than sister workers' sons (0.15). This study shows that worker policing also has a low cost in terms of the killing of queen-laid eggs, as only a small proportion of queen-laid eggs are killed, most of which are rapidly replaced.

  13. Dominance and queen succession in captive colonies of the eusocial naked mole-rat, Heterocephalus glaber.

    PubMed Central

    Clarke, F M; Faulkes, C G

    1997-01-01

    Naked mole-rat colonies exhibit a high reproductive skew, breeding being typically restricted to one female (the 'queen') and one to three males. Other colony members are reproductively suppressed, although this suppression can be reversed following the removal or death of the queen. We examined dominance and queen succession within captive colonies to investigate the relationship between urinary testosterone and cortisol, dominance rank and reproductive status; and to determine if behavioural and/or physiological parameters can be used as predictors of queen succession. Social structure was characterized by a linear dominance hierarchy before and after queen removal. Prior to queen removal, dominance rank was negatively correlated with body weight and urinary testosterone and cortisol titres in males and females. Queen removal results in social instability and aggression between high ranking individuals. Dominance rank appears to be a good predictor of reproductive status: queens are the highest ranking colony females and are succeeded by the next highest ranking females. The intense dominance-related aggression that accompanies reproductive succession in naked mole-rats provides empirical support for optimal skew theory. PMID:9263466

  14. Potential increase in mating frequency of queens in feral colonies of Bombus terrestris introduced into Japan

    NASA Astrophysics Data System (ADS)

    Inoue, Maki N.; Saito, Fuki; Tsuchida, Koji; Goka, Koichi

    2012-10-01

    With the exception of several species, bumblebees are monandrous. We examined mating frequency in feral colonies of the introduced bumblebee Bombus terrestris in Japan . Using microsatellite markers, genotyping of sperm DNA stored in the spermatheca of nine queens detected multiple insemination paternities in one queen; the others were singly mated. The average effective paternity frequency estimated from the genotypes of queens and workers was 1.23; that estimated from the workers' genotype alone was 2.12. These values were greater than those of laboratory-reared colonies in the native ranges of B. terrestris. The genotypes of one or two workers did not match those of their queens or showed paternities different from those of their nestmates; this may have arisen from either queen takeover or drifting of workers. These alien workers were responsible for the heterogeneous genotype distribution within each B. terrestris colony, resulting in higher estimates of paternity frequency than of insemination frequency. The high mating frequency of introduced B. terrestris may have occurred by artificial selection through mass breeding for commercialization. Moreover, polyandrous queens may be selectively advantageous, because reproduction by such queens is less likely to be disturbed by interspecific mating than that by monandrous queens.

  15. Queens defense by workers in the highly polygynous ant Crematogaster pygmaea (Hymenoptera: Myrmicinae).

    PubMed

    Martins Segundo, Glauco Bezerra; de Biseau, Jean-Christophe; Quinet, Yves

    2012-11-01

    Some aspects of the biology of Crematogaster pygmaea, a highly polydomous and polygynous ant, are more commonly found in monogynous species. One such characteristic is the high attractiveness of its queens. In this study, this attractiveness was assessed under varying experimental conditions to investigate the factors responsible for its expression and variation, and to identify the nature of queen attractiveness. It was shown (1) that C. pygmaea queens are highly attractive to the workers that cluster on and around them (retinue), (2) that the attractiveness of C. pygmaea queens is context-dependent, i.e., it increases with increasing degree of potential danger to the queen, (3) that the attractiveness signal of C. pygmaea queens is chemically based, and (4) that this signal is persistent and apparently not colony-specific. The proposed hypothesis is that the C. pygmaea queens constantly release an attractiveness signal that is "read" by the workers, in a dependent way linked to the context, and that the main function of this attractiveness is to protect queens. This protection would have a high adaptive value in the context of the social structure and the reproductive strategies in C. pygmaea.

  16. Chronic Bee Paralysis Virus in Honeybee Queens: Evaluating Susceptibility and Infection Routes

    PubMed Central

    Amiri, Esmaeil; Meixner, Marina; Büchler, Ralph; Kryger, Per

    2014-01-01

    Chronic bee paralysis virus (CBPV) is known as a disease of worker honey bees. To investigate pathogenesis of the CBPV on the queen, the sole reproductive individual in a colony, we conducted experiments regarding the susceptibility of queens to CBPV. Results from susceptibility experiment showed a similar disease progress in the queens compared to worker bees after infection. Infected queens exhibit symptoms by Day 6 post infection and virus levels reach 1011 copies per head. In a transmission experiment we showed that social interactions may affect the disease progression. Queens with forced contact to symptomatic worker bees acquired an overt infection with up to 1011 virus copies per head in six days. In contrast, queens in contact with symptomatic worker bees, but with a chance to receive food from healthy bees outside the cage appeared healthy. The virus loads did not exceed 107 in the majority of these queens after nine days. Symptomatic worker bees may transmit sufficient active CBPV particles to the queen through trophallaxis, to cause an overt infection. PMID:24618857

  17. Comparative toxicity of acaricides to honey bee (Hymenoptera: Apidae) workers and queens.

    PubMed

    Dahlgren, Lizette; Johnson, Reed M; Siegfried, Blair D; Ellis, Marion D

    2012-12-01

    Acaricides are used to treat honey bee (Apis mellifera L.) colonies to control the varroa mite (Varroa destructor Anderson & Trueman), a worldwide threat to honey bee health. Although acaricides control a serious honey bee parasite and mitigate bee loss, they may cause harm to bees as well. We topically applied five acaricides, each with a different mode of action, to young adult queen and worker bees to generate dose-response curves and LD50. Twenty-four hours after treatment, queens were found to be three-times more tolerant of tau-fluvalinate and six-times more tolerant of thymol than workers when adjusted for body weight differences between workers (108 mg) and queens (180 mg). Queens survived the highest administered doses of fenpyroximate (1620 microg/g) and coumaphos (2700 microg/g) indicating that queens are at least 11-fold more tolerant of coumaphos and at least 54-fold more tolerant of fenpyroximate than workers. However, queens treated with as little as 54 microg/g of fenpyroximate exhibited reduced survival over 6 wk after treatment. Amitraz was the only acaricide tested for which queens were not more tolerant than workers. The striking difference in acaricide tolerance of queen and worker honey bees suggests physiological differences in how the two castes are affected by xenobiotics.

  18. Effects of honey bee (Apis mellifera L.) queen insemination volume on worker behavior and physiology

    USDA-ARS?s Scientific Manuscript database

    Honey bee colonies consist of tens of thousands of workers and a single reproductive queen that produces a pheromone blend which maintains colony organization. Previous studies indicated that the insemination quantity and volume alter queen mandibular pheromone profiles. In our 11-month long field s...

  19. Paleoecological analyses of lake sediments reveal prehistoric human impact on forests at Anthony Island UNESCO World Heritage Site, Queen Charlotte Islands (Haida Gwaii), Canada

    NASA Astrophysics Data System (ADS)

    Lacourse, Terri; Mathewes, Rolf W.; Hebda, Richard J.

    2007-09-01

    Pollen and plant macrofossil analyses of lake sediments from Anthony Island in the southern Queen Charlotte Islands (Haida Gwaii), British Columbia, reveal 1800 yr of relatively stable temperate rainforest vegetation. Cupressaceae (cedar) pollen percentages and accumulation rates decline about 1000 cal yr BP, coincident with occupation of the island by Haida peoples, who use Thuja plicata (western red cedar) almost exclusively for house construction, dugout canoes, monumental poles, and many other items. Anthropogenic disturbance offers the most likely explanation for the decline of T. plicata.

  20. Evolution and hydrocarbon potential of Queen Charlotte basin, Canada

    SciTech Connect

    McWhae, J.R.

    1988-02-01

    The structural and depositional history of the Queen Charlotte basin, a complex Tertiary rift basin with extensive coeval volcanics, involves regional geology from the Pacific plate west of the Queen Charlotte transform fault to east of the Alexander-Wrangellia terrane, based on geophysics (including newly released seismic lines), revised stratigraphy, and well data. Eight offshore wells were drilled prior to 1970 and nine shallow onshore wells were drilled in or beyond the northwestern margin of the basin. The wells provide data on porosity, seal, maturation (geothermal and vitrinite reflectance data), and oil stains in sidewall cores of the Sockeye B-10 well in the Skonun formation, here 4500 m thick. The Skonun ranges from early Miocene (17 Ma) to latest Pliocene (2 Ma) in age and the lower part is regarded as the primary hydrocarbon objective, especially in the more southern part of the basin where more favorable depositional porosities occur in paralic and shelf sandstones. Higher-than-average geothermal temperatures, locally in the southwest corner of the basin related to oblique subduction of very young oceanic crust, may reach the hydrocarbon-generating threshold in the lower Skonun marine shales. The middle Cretaceous Haida subarkose appears to be a secondary reservoir - the thickest and cleanest of the post-collision volcaniclastics. Highly organic Lower Jurassic shales provide a second, probably oil-prone, source.

  1. Peripheral modulation of worker bee responses to queen mandibular pheromone.

    PubMed

    Vergoz, Vanina; McQuillan, H James; Geddes, Lisa H; Pullar, Kiri; Nicholson, Brad J; Paulin, Michael G; Mercer, Alison R

    2009-12-08

    It is generally accepted that young worker bees (Apis mellifera L.) are highly attracted to queen mandibular pheromone (QMP). Our results challenge this widely held view. We have found that unless young workers are exposed to QMP early in adult life, they, like foragers, avoid contact with this pheromone. Our data indicate that responses to QMP are regulated peripherally, at the level of the antennal sensory neurons, and that a window of opportunity exists in which QMP can alter a young bee's response to this critically important pheromone. Exposing young bees to QMP from the time of adult emergence reduces expression in the antennae of the D1-like dopamine receptor gene, Amdop1. Levels of Amdop3 transcript, on the other hand, and of the octopamine receptor gene Amoa1, are significantly higher in the antennae of bees strongly attracted to QMP than in bees showing no attraction to this pheromone. A decline in QMP attraction with age is accompanied by a fall in expression in worker antennae of the D2-like dopamine receptor, AmDOP3, a receptor that is selectively activated by QMP. Taken together, our findings suggest that QMP's actions peripherally not only suppress avoidance behavior, but also enhance attraction to QMP, thereby facilitating attendance of the queen.

  2. Genetic reincarnation of workers as queens in the Eastern honeybee Apis cerana.

    PubMed

    Holmes, M J; Tan, K; Wang, Z; Oldroyd, B P; Beekman, M

    2015-01-01

    Thelytokous parthenogenesis, or the asexual production of female offspring, is rare in the animal kingdom, but relatively common in social Hymenoptera. However, in honeybees, it is only known to be ubiquitous in one subspecies of Apis mellifera, the Cape honeybee, A. mellifera capensis. Here we report the appearance of queen cells in two colonies of the Eastern honeybee Apis cerana that no longer contained a queen or queen-produced brood to rear queens from. A combination of microsatellite genotyping and the timing of the appearance of these individuals excluded the possibility that they had been laid by the original queen. Based on the genotypes of these individuals, thelytokous production by natal workers is the most parsimonious explanation for their existence. Thus, we present the first example of thelytoky in a honeybee outside A. mellifera. We discuss the evolutionary and ecological consequences of thelytoky in A. cerana, in particular the role thelytoky may play in the recent invasions by populations of this species.

  3. Similar policing rates of eggs laid by virgin and mated honey-bee queens

    NASA Astrophysics Data System (ADS)

    Beekman, Madeleine; Martin, Caroline G.; Oldroyd, Benjamin P.

    2004-12-01

    Worker-policing is a well-documented mechanism that maintains functional worker sterility in queenright honey-bee colonies. Unknown, however, is the source of the egg-marking signal that is thought to be produced by the queen and used by policing workers to discriminate between queen- and worker-laid eggs. Here we investigate whether mating is necessary for the queen to produce the egg-marking signal. We compare the removal rate of eggs laid by virgin queens and compare this rate with that of eggs laid by mated queens. Our results show that mating does not affect the acceptability of eggs, suggesting that physiological changes linked to the act of mating do not play a role in the production of the queen’s egg-marking signal.

  4. Higher expression of somatic repair genes in long-lived ant queens than workers

    PubMed Central

    Lucas, Eric R.; Privman, Eyal; Keller, Laurent

    2016-01-01

    Understanding why organisms senesce is a fundamental question in biology. One common explanation is that senescence results from an increase in macromolecular damage with age. The tremendous variation in lifespan between genetically identical queen and worker ants, ranging over an order of magnitude, provides a unique system to study how investment into processes of somatic maintenance and macromolecular repair influence lifespan. Here we use RNAseq to compare patterns of expression of genes involved in DNA and protein repair of age-matched queens and workers. There was no difference between queens and workers in 1-day-old individuals, but the level of expression of these genes increased with age and this up-regulation was greater in queens than in workers, resulting in significantly queen-biased expression in 2-month-old individuals in both legs and brains. Overall, these differences are consistent with the hypothesis that higher longevity is associated with increased investment into somatic repair. PMID:27617474

  5. Queen and worker policing in monogynous and monandrous colonies of a primitively eusocial wasp.

    PubMed

    Saigo, T; Tsuchida, K

    2004-12-07

    Kin-selection theory predicts that a worker prefers to produce her own sons in a colony with monandry and monogyny because relatedness to her sons (0.5) and nephews (0.375) exceeds that to brothers (0.25). In spite of this prediction, recent studies reveal that workers police each other (mutual-worker egg removal) even in monandrous and monogynous colonies. We conducted field and laboratory studies to evaluate queen and worker policing in queen-right colonies of the primitively eusocial wasp Polistes chinensis antennalis. Genetic studies using microsatellite markers, as well as extensive observations of natural colonies, revealed that both queen and workers removed both queen- and worker-laid eggs in monogynous and monandrous colonies. The queen's eggs survived to hatching more successfully than those of the workers (88.5% versus 1.4%). We discuss the likely factors to explain these worker-policing behaviours.

  6. Queen and worker policing in monogynous and monandrous colonies of a primitively eusocial wasp.

    PubMed Central

    Saigo, T; Tsuchida, K

    2004-01-01

    Kin-selection theory predicts that a worker prefers to produce her own sons in a colony with monandry and monogyny because relatedness to her sons (0.5) and nephews (0.375) exceeds that to brothers (0.25). In spite of this prediction, recent studies reveal that workers police each other (mutual-worker egg removal) even in monandrous and monogynous colonies. We conducted field and laboratory studies to evaluate queen and worker policing in queen-right colonies of the primitively eusocial wasp Polistes chinensis antennalis. Genetic studies using microsatellite markers, as well as extensive observations of natural colonies, revealed that both queen and workers removed both queen- and worker-laid eggs in monogynous and monandrous colonies. The queen's eggs survived to hatching more successfully than those of the workers (88.5% versus 1.4%). We discuss the likely factors to explain these worker-policing behaviours. PMID:15801618

  7. Conserved class of queen pheromones stops social insect workers from reproducing.

    PubMed

    Van Oystaeyen, Annette; Oliveira, Ricardo Caliari; Holman, Luke; van Zweden, Jelle S; Romero, Carmen; Oi, Cintia A; d'Ettorre, Patrizia; Khalesi, Mohammadreza; Billen, Johan; Wäckers, Felix; Millar, Jocelyn G; Wenseleers, Tom

    2014-01-17

    A major evolutionary transition to eusociality with reproductive division of labor between queens and workers has arisen independently at least 10 times in the ants, bees, and wasps. Pheromones produced by queens are thought to play a key role in regulating this complex social system, but their evolutionary history remains unknown. Here, we identify the first sterility-inducing queen pheromones in a wasp, bumblebee, and desert ant and synthesize existing data on compounds that characterize female fecundity in 64 species of social insects. Our results show that queen pheromones are strikingly conserved across at least three independent origins of eusociality, with wasps, ants, and some bees all appearing to use nonvolatile, saturated hydrocarbons to advertise fecundity and/or suppress worker reproduction. These results suggest that queen pheromones evolved from conserved signals of solitary ancestors.

  8. Queen Specific Exocrine Glands in Legionary Ants and Their Possible Function in Sexual Selection

    PubMed Central

    Hölldobler, Bert

    2016-01-01

    The colonies of army ants and some other legionary ant species have single, permanently wingless queens with massive post petioles and large gasters. Such highly modified queens are called dichthadiigynes. This paper presents the unusually rich exocrine gland endowment of dichthadiigynes, which is not found in queens of other ant species. It has been suggested these kinds of glands produce secretions that attract and maintain worker retinues around queens, especially during migration. However, large worker retinues also occur in non-legionary species whose queens do not have such an exuberance of exocrine glands. We argue and present evidence in support of our previously proposed hypothesis that the enormous outfit of exocrine glands found in dichthadiigynes is due to sexual selection mediated by workers as the main selecting agents. PMID:26986740

  9. 76 FR 23907 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Queen Conch Fishery of Puerto...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-29

    ..., Gulf of Mexico, and South Atlantic; Queen Conch Fishery of Puerto Rico and the U.S. Virgin Islands... to address overfishing of Caribbean queen conch in the U.S. Caribbean. This rule extends the queen... Atlantic. Therefore, all for-hire businesses that may be affected by this final rule are determined,...

  10. An Efficient Antioxidant System in a Long-Lived Termite Queen

    PubMed Central

    Tasaki, Eisuke; Kobayashi, Kazuya; Matsuura, Kenji; Iuchi, Yoshihito

    2017-01-01

    The trade-off between reproduction and longevity is known in wide variety of animals. Social insect queens are rare organisms that can achieve a long lifespan without sacrificing fecundity. The extended longevity of social insect queens, which contradicts the trade-off, has attracted much attention because it implies the existence of an extraordinary anti-aging mechanism. Here, we show that queens of the termite Reticulitermes speratus incur significantly lower oxidative damage to DNA, protein and lipid and have higher activity of antioxidant enzymes than non-reproductive individuals (workers and soldiers). The levels of 8-hydroxy-2’-deoxyguanosine (oxidative damage marker of DNA) were lower in queens than in workers after UV irradiation. Queens also showed lower levels of protein carbonyls and malondialdehyde (oxidative damage markers of protein and lipid, respectively). The antioxidant enzymes of insects are generally composed of catalase (CAT) and peroxiredoxin (Prx). Queens showed more than two times higher CAT activity and more than seven times higher expression levels of the CAT gene RsCAT1 than workers. The CAT activity of termite queens was also markedly higher in comparison with other solitary insects and the queens of eusocial Hymenoptera. In addition, queens showed higher expression levels of the Prx gene RsPRX6. These results suggested that this efficient antioxidant system can partly explain why termite queens achieve long life. This study provides important insights into the evolutionary linkage of reproductive division of labor and the development of queens’ oxidative stress resistance in social insects. PMID:28076409

  11. Gigantism in honeybees: Apis cerana queens reared in mixed-species colonies

    NASA Astrophysics Data System (ADS)

    Tan, Ken; Hepburn, H. R.; He, Shaoyu; Radloff, S. E.; Neumann, P.; Fang, Xiang

    2006-07-01

    The development of animals depends on both genetic and environmental effects to a varying extent. Their relative influences can be evaluated in the social insects by raising the intracolonial diversity to an extreme in nests consisting of workers from more than one species. In this study, we studied the effects of mixed honeybee colonies of Apis mellifera and Apis cerana on the rearing of grafted queen larvae of A. cerana. A. mellifera sealed worker brood was introduced into A. cerana colonies and on emergence, the adults were accepted. Then, A. cerana larvae were grafted for queen rearing into two of these mixed-species colonies. Similarly, A. cerana larvae and A. mellifera larvae were also grafted conspecifically as controls. The success rate of A. cerana queen rearing in the test colonies was 64.5%, surpassing all previous attempts at interspecific queen rearing. After emergence, all virgin queens obtained from the three groups ( N=90) were measured morphometrically. The A. cerana queens from the mixed-species colonies differed significantly in size and pigmentation from the A. cerana control queens and closely approximated the A. mellifera queens. It is inferred that these changes in the A. cerana queens reared in the mixed-species colonies can be attributed to feeding by heterospecific nurse bees and/or chemical differences in royal jelly. Our data show a strong impact of environment on the development of queens. The results further suggest that in honeybees the cues for brood recognition can be learned by heterospecific workers after eclosion, thereby providing a novel analogy to slave making in ants.

  12. Social regulation of maternal traits in nest-founding bumble bee (Bombus terrestris) queens

    PubMed Central

    Woodard, S. Hollis; Bloch, Guy; Band, Mark R.; Robinson, Gene E.

    2013-01-01

    SUMMARY During the nest-founding phase of the bumble bee colony cycle, queens undergo striking changes in maternal care behavior. Early in the founding phase, prior to the emergence of workers in the nest, queens are reproductive and also provision and feed their offspring. However, later in the founding phase, queens reduce their feeding of larvae and become specialized on reproduction. This transition is synchronized with the emergence of workers in the colony, who assume the task of feeding their siblings. Using a social manipulation experiment with the bumble bee Bombus terrestris, we tested the hypothesis that workers regulate the transition from feeding brood to specialization on reproduction in nest-founding bumble bee queens. Consistent with this hypothesis, we found that early-stage nest-founding queens with workers prematurely added to their nests reduce their brood-feeding behavior and increase egg laying, and likewise, late-stage nest-founding queens increase their brood-feeding behavior and decrease egg-laying when workers are removed from their nests. Further, brood-feeding and egg-laying behaviors were negatively correlated. We used Agilent microarrays designed from B. terrestris brain expressed sequenced tags (ESTs) to explore a second hypothesis, that workers alter brain gene expression in nest-founding queens. We found evidence that brain gene expression in nest-founding queens is altered by the presence of workers, with the effect being much stronger in late-stage founding queens. This study provides new insights into how the transition from feeding brood to specialization on reproduction in queen bumble bees is regulated during the nest initiation phase of the colony cycle. PMID:23966589

  13. Study of doubly strange systems using stored antiprotons

    NASA Astrophysics Data System (ADS)

    Singh, B.; Erni, W.; Krusche, B.; Steinacher, M.; Walford, N.; Liu, B.; Liu, H.; Liu, Z.; Shen, X.; Wang, C.; Zhao, J.; Albrecht, M.; Erlen, T.; Fink, M.; Heinsius, F.; Held, T.; Holtmann, T.; Jasper, S.; Keshk, I.; Koch, H.; Kopf, B.; Kuhlmann, M.; Kümmel, M.; Leiber, S.; Mikirtychyants, M.; Musiol, P.; Mustafa, A.; Pelizäus, M.; Pychy, J.; Richter, M.; Schnier, C.; Schröder, T.; Sowa, C.; Steinke, M.; Triffterer, T.; Wiedner, U.; Ball, M.; Beck, R.; Hammann, C.; Ketzer, B.; Kube, M.; Mahlberg, P.; Rossbach, M.; Schmidt, C.; Schmitz, R.; Thoma, U.; Urban, M.; Walther, D.; Wendel, C.; Wilson, A.; Bianconi, A.; Bragadireanu, M.; Caprini, M.; Pantea, D.; Patel, B.; Czyzycki, W.; Domagala, M.; Filo, G.; Jaworowski, J.; Krawczyk, M.; Lisowski, E.; Lisowski, F.; Michałek, M.; Poznański, P.; Płażek, J.; Korcyl, K.; Kozela, A.; Kulessa, P.; Lebiedowicz, P.; Pysz, K.; Schäfer, W.; Szczurek, A.; Fiutowski, T.; Idzik, M.; Mindur, B.; Przyborowski, D.; Swientek, K.; Biernat, J.; Kamys, B.; Kistryn, S.; Korcyl, G.; Krzemien, W.; Magiera, A.; Moskal, P.; Psyzniak, A.; Rudy, Z.; Salabura, P.; Smyrski, J.; Strzempek, P.; Wronska, A.; Augustin, I.; Böhm, R.; Lehmann, I.; Nicmorus Marinescu, D.; Schmitt, L.; Varentsov, V.; Al-Turany, M.; Belias, A.; Deppe, H.; Dzhygadlo, R.; Ehret, A.; Flemming, H.; Gerhardt, A.; Götzen, K.; Gromliuk, A.; Gruber, L.; Karabowicz, R.; Kliemt, R.; Krebs, M.; Kurilla, U.; Lehmann, D.; Löchner, S.; Lühning, J.; Lynen, U.; Orth, H.; Patsyuk, M.; Peters, K.; Saito, T.; Schepers, G.; Schmidt, C. J.; Schwarz, C.; Schwiening, J.; Täschner, A.; Traxler, M.; Ugur, C.; Voss, B.; Wieczorek, P.; Wilms, A.; Zühlsdorf, M.; Abazov, V. M.; Alexeev, G.; Arefiev, A.; Astakhov, V. I.; Barabanov, M. Yu.; Batyunya, B. V.; Davydov, Yu. I.; Dodokhov, V. Kh.; Efremov, A. A.; Fechtchenko, A.; Fedunov, A. G.; Galoyan, A.; Grigoryan, S.; Koshurnikov, E. K.; Lobanov, V. I.; Lobanov, Y. Yu.; Makarov, A. F.; Malinina, L. V.; Malyshev, V. L.; Olshevskiy, A.; Perevalova, E.; Piskun, A. A.; Pocheptsov, T.; Pontecorvo, G.; Rodionov, V.; Rogov, Y.; Salmin, R.; Samartsev, A.; Sapozhnikov, M. G.; Shabratova, G.; Skachkov, N. B.; Skachkova, A. N.; Strokovsky, E. A.; Suleimanov, M.; Teshev, R.; Tokmenin, V.; Uzhinsky, V.; Vodopyanov, A.; Zaporozhets, S. A.; Zhuravlev, N. I.; Zorin, A. G.; Branford, D.; Glazier, D.; Watts, D.; Böhm, M.; Britting, A.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Dobbs, S.; Seth, K.; Tomaradze, A.; Xiao, T.; Bettoni, D.; Carassiti, V.; Cotta Ramusino, A.; Dalpiaz, P.; Drago, A.; Fioravanti, E.; Garzia, I.; Savriè, M.; Akishina, V.; Kisel, I.; Kozlov, G.; Pugach, M.; Zyzak, M.; Gianotti, P.; Guaraldo, C.; Lucherini, V.; Bersani, A.; Bracco, G.; Macri, M.; Parodi, R. F.; Biguenko, K.; Brinkmann, K.; Di Pietro, V.; Diehl, S.; Dormenev, V.; Drexler, P.; Düren, M.; Etzelmüller, E.; Galuska, M.; Gutz, E.; Hahn, C.; Hayrapetyan, A.; Kesselkaul, M.; Kühn, W.; Kuske, T.; Lange, J. S.; Liang, Y.; Metag, V.; Nanova, M.; Nazarenko, S.; Novotny, R.; Quagli, T.; Reiter, S.; Rieke, J.; Rosenbaum, C.; Schmidt, M.; Schnell, R.; Stenzel, H.; Thöring, U.; Ullrich, M.; Wagner, M. N.; Wasem, T.; Wohlfarth, B.; Zaunick, H.; Ireland, D.; Rosner, G.; Seitz, B.; Deepak, P. N.; Kulkarni, A.; Apostolou, A.; Babai, M.; Kavatsyuk, M.; Lemmens, P.; Lindemulder, M.; Loehner, H.; Messchendorp, J.; Schakel, P.; Smit, H.; Tiemens, M.; van der Weele, J. C.; Veenstra, R.; Vejdani, S.; Dutta, K.; Kalita, K.; Kumar, A.; Roy, A.; Sohlbach, H.; Bai, M.; Bianchi, L.; Büscher, M.; Cao, L.; Cebulla, A.; Dosdall, R.; Gillitzer, A.; Goldenbaum, F.; Grunwald, D.; Herten, A.; Hu, Q.; Kemmerling, G.; Kleines, H.; Lehrach, A.; Nellen, R.; Ohm, H.; Orfanitski, S.; Prasuhn, D.; Prencipe, E.; Pütz, J.; Ritman, J.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Sterzenbach, G.; Stockmanns, T.; Wintz, P.; Wüstner, P.; Xu, H.; Zambanini, A.; Li, S.; Li, Z.; Sun, Z.; Xu, H.; Rigato, V.; Isaksson, L.; Achenbach, P.; Corell, O.; Denig, A.; Distler, M.; Hoek, M.; Karavdina, A.; Lauth, W.; Liu, Z.; Merkel, H.; Müller, U.; Pochodzalla, J.; Schlimme, S.; Sfienti, C.; Thiel, M.; Ahmadi, H.; Ahmed, S.; Bleser, S.; Capozza, L.; Cardinali, M.; Dbeyssi, A.; Deiseroth, M.; Feldbauer, F.; Fritsch, M.; Fröhlich, B.; Jasinski, P.; Kang, D.; Khaneft, D.; Klasen, R.; Leithoff, H. H.; Lin, D.; Maas, F.; Maldaner, S.; Martìnez Rojo, M.; Marta, M.; Michel, M.; Mora Espì, M. C.; Morales Morales, C.; Motzko, C.; Nerling, F.; Noll, O.; Pflüger, S.; Pitka, A.; Rodríguez Piñeiro, D.; Sanchez Lorente, A.; Steinen, M.; Valente, R.; Weber, T.; Zambrana, M.; Zimmermann, I.; Fedorov, A.; Korjik, M.; Missevitch, O.; Boukharov, A.; Malyshev, O.; Marishev, I.; Balanutsa, P.; Balanutsa, V.; Chernetsky, V.; Demekhin, A.; Dolgolenko, A.; Fedorets, P.; Gerasimov, A.; Goryachev, V.; Chandratre, V.; Datar, V.; Dutta, D.; Jha, V.; Kumawat, H.; Mohanty, A. K.; Parmar, A.; Roy, B.; Sonika, G.; Fritzsch, C.; Grieser, S.; Hergemöller, A. K.; Hetz, B.; Hüsken, N.; Khoukaz, A.; Wessels, J. P.; Khosonthongkee, K.; Kobdaj, C.; Limphirat, A.; Srisawad, P.; Yan, Y.; Barnyakov, M.; Barnyakov, A. Yu.; Beloborodov, K.; Blinov, A. E.; Blinov, V. E.; Bobrovnikov, V. S.; Kononov, S.; Kravchenko, E. A.; Kuyanov, I. A.; Martin, K.; Onuchin, A. P.; Serednyakov, S.; Sokolov, A.; Tikhonov, Y.; Atomssa, E.; Kunne, R.; Marchand, D.; Ramstein, B.; Van de Wiele, J.; Wang, Y.; Boca, G.; Costanza, S.; Genova, P.; Montagna, P.; Rotondi, A.; Abramov, V.; Belikov, N.; Bukreeva, S.; Davidenko, A.; Derevschikov, A.; Goncharenko, Y.; Grishin, V.; Kachanov, V.; Kormilitsin, V.; Levin, A.; Melnik, Y.; Minaev, N.; Mochalov, V.; Morozov, D.; Nogach, L.; Poslavskiy, S.; Ryazantsev, A.; Ryzhikov, S.; Semenov, P.; Shein, I.; Uzunian, A.; Vasiliev, A.; Yakutin, A.; Tomasi-Gustafsson, E.; Roy, U.; Yabsley, B.; Belostotski, S.; Gavrilov, G.; Izotov, A.; Manaenkov, S.; Miklukho, O.; Veretennikov, D.; Zhdanov, A.; Makonyi, K.; Preston, M.; Tegner, P.; Wölbing, D.; Bäck, T.; Cederwall, B.; Rai, A. K.; Godre, S.; Calvo, D.; Coli, S.; De Remigis, P.; Filippi, A.; Giraudo, G.; Lusso, S.; Mazza, G.; Mignone, M.; Rivetti, A.; Wheadon, R.; Balestra, F.; Iazzi, F.; Introzzi, R.; Lavagno, A.; Olave, J.; Amoroso, A.; Bussa, M. P.; Busso, L.; De Mori, F.; Destefanis, M.; Fava, L.; Ferrero, L.; Greco, M.; Hu, J.; Lavezzi, L.; Maggiora, M.; Maniscalco, G.; Marcello, S.; Sosio, S.; Spataro, S.; Birsa, R.; Bradamante, F.; Bressan, A.; Martin, A.; Calen, H.; Ikegami Andersson, W.; Johansson, T.; Kupsc, A.; Marciniewski, P.; Papenbrock, M.; Pettersson, J.; Schönning, K.; Wolke, M.; Galnander, B.; Diaz, J.; Pothodi Chackara, V.; Chlopik, A.; Kesik, G.; Melnychuk, D.; Slowinski, B.; Trzcinski, A.; Wojciechowski, M.; Wronka, S.; Zwieglinski, B.; Bühler, P.; Marton, J.; Steinschaden, D.; Suzuki, K.; Widmann, E.; Zmeskal, J.; Gerl, Jürgen; Kojouharov, Ivan; Kojouharova, Jasmina

    2016-10-01

    Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P ‾ ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ--atoms will be feasible and even the production of Ω--atoms will be within reach. The latter might open the door to the | S | = 3 world in strangeness nuclear physics, by the study of the hadronic Ω--nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions.

  14. Some measurements for determining strangeness matrix elements in the nucleon

    SciTech Connect

    Henley, E.M.; Pollock, S.J.; Ying, S.; Frederico, T.; Krein,; Williams, A.G.

    1991-12-31

    Some experiments to measure strangeness matrix elements of the proton are proposed. Two of these suggestions are described in some detail, namely electro-production of phi mesons and the difference between neutrino and antineutrino scattering for isospin zero targets such as deuterium.

  15. Some measurements for determining strangeness matrix elements in the nucleon

    SciTech Connect

    Henley, E.M.; Pollock, S.J.; Ying, S. ); Frederico, T. , Sao Jose dos Campos, SP . Inst. de Estudos Avancados); Krein, . Inst. de Fisica Teorica); Williams, A.G. )

    1991-01-01

    Some experiments to measure strangeness matrix elements of the proton are proposed. Two of these suggestions are described in some detail, namely electro-production of phi mesons and the difference between neutrino and antineutrino scattering for isospin zero targets such as deuterium.

  16. Exploring Strange Nonchaotic Attractors through Jacobian Elliptic Functions

    ERIC Educational Resources Information Center

    Garcia-Hoz, A. Martinez; Chacon, R.

    2011-01-01

    We demonstrate the effectiveness of Jacobian elliptic functions (JEFs) for inquiring into the reshaping effect of quasiperiodic forces in nonlinear nonautonomous systems exhibiting strange nonchaotic attractors (SNAs). Specifically, we characterize analytically and numerically some reshaping-induced transitions starting from SNAs in the context of…

  17. Exploring Strange Nonchaotic Attractors through Jacobian Elliptic Functions

    ERIC Educational Resources Information Center

    Garcia-Hoz, A. Martinez; Chacon, R.

    2011-01-01

    We demonstrate the effectiveness of Jacobian elliptic functions (JEFs) for inquiring into the reshaping effect of quasiperiodic forces in nonlinear nonautonomous systems exhibiting strange nonchaotic attractors (SNAs). Specifically, we characterize analytically and numerically some reshaping-induced transitions starting from SNAs in the context of…

  18. Strangeness -2 and -3 Baryons in a Constituent Quark Model

    SciTech Connect

    Muslema Pervin; Winston Roberts

    2007-09-19

    We apply a quark model developed in earlier work to the spectrum of baryons with strangeness -2 and -3. The model describes a number of well-established baryons successfully, and application to cascade baryons allows the quantum numbers of some known states to be deduced.

  19. Familiar-Strange: Teaching the Scripture as John Would Teach

    ERIC Educational Resources Information Center

    Ha, Tung-Chiew

    2014-01-01

    The Gospel of John teaches through telling the story of Jesus in light of the familiar Hebrew faith stories. It is an interpretive task that presents Jesus to his audience and teaches them adequate faith. John the Teacher skillfully uses narrative skills to create the familiar-strange effect in his storytelling. Each story is followed by a…

  20. Measuring Infant-Mother Attachment: Is the Strange Situation Enough?

    ERIC Educational Resources Information Center

    Clarke-Stewart, K. Alison; Goossens, Frits A.; Allhusen, Virginia D.

    2001-01-01

    Examined validity of the California Attachment Procedure (CAP), which does not involve mother-child separations. Overall, toddlers were more likely to be classified as secure in the CAP than in the Strange Situation (SS) test. The CAP yielded higher rates of security, particularly for children in day care, and security in the CAP correlated more…

  1. Strange vector form factors from parity-violating electron scattering

    SciTech Connect

    Kent Paschke, Anthony Thomas, Robert Michaels, David Armstrong

    2011-06-01

    The simplest models might describe the nucleon as 3 light quarks, but this description would be incomplete without inclusion of the sea of glue and qbar q pairs which binds it. Early indications of a particularly large contribution from strange quarks in this sea to the spin and mass of the nucleon motivated an experimental program examining the role of these strange quarks in the nucleon vector form factors. The strangeness form factors can be extracted from the well-studied electromagnetic structure of the nucleon using parity-violation in electron-nuclear scattering to isolate the effect of the weak interaction. With high luminosity and polarization, and a very stable beam due to its superconducting RF cavities, CEBAF at Jefferson Lab is a precision instrument uniquely well suited to the challenge of measurements of the small parity-violating asymmetries. The techniques and results of the two major Jefferson Lab experimental efforts in parity-violation studies, HAPPEX and G0, as well as efforts to describe the strange form factors in QCD, will be reviewed.

  2. Oral osteomyelitis: pre-AIDS manifestation or strange coincidence?

    PubMed

    Harel-Raviv, M; Gorsky, M; Lust, I; Raviv, E

    1996-01-01

    A bizarre and unexplained localized osteomyelitis was discovered in the mandible of an otherwise apparently healthy 36-year-old man. This strange oral manifestation was followed 2 years later by a diagnosis of Pneumocystis carinii pneumonia, which indicated full-blown AIDS. Could osteomyelitis of the mandible be an alarming oral manifestation of AIDS before the disease is manifested in other ways?

  3. Surface effects in color superconducting strange-quark matter

    SciTech Connect

    Oertel, Micaela; Urban, Michael

    2008-04-01

    Surface effects in strange-quark matter play an important role for certain observables which have been proposed in order to identify strange stars, and color superconductivity can strongly modify these effects. We study the surface of color superconducting strange-quark matter by solving the Hartree-Fock-Bogoliubov equations for finite systems ('strangelets') within the MIT bag model, supplemented with a pairing interaction. Because of the bag-model boundary condition, the strange-quark density is suppressed at the surface. This leads to a positive surface charge, concentrated in a layer of {approx}1 fm below the surface, even in the color-flavor locked (CFL) phase. However, since in the CFL phase all quarks are paired, this positive charge is compensated by a negative charge, which turns out to be situated in a layer of a few tens of fm below the surface, and the total charge of CFL strangelets is zero. We also study the surface and curvature contributions to the total energy. Because of the strong pairing, the energy as a function of the mass number is very well reproduced by a liquid-drop type formula with curvature term.

  4. Probing the strange nature of the nucleon with phi photoproduction

    SciTech Connect

    Lowry, M.M.

    1997-03-06

    The presence inside the nucleon of a significant component of strange-antistrange quark pairs has been invoked to explain a number of current puzzles in the low energy realm of QCD. The {sigma} term in {pi}N scattering is a venerable conundrum which can be explained with a 10%--20% admixture. The spin crisis brought on by the EMC result and follow on experiments was first interpreted as requiring a large strange content of s quarks whose spin helped cancel the contribution of the u and d quarks to the nucleon spin, again of order 10%. Excess phi meson production in p{anti p} annihilation at LEAR has also been explained in terms of up to a 19% admixture of s{anti s} pairs. Charm production in deep-inelastic neutrino scattering would appear to provide evidence for a 3% strange sea. It is clear that a definite probe of the strange quark content would be an invaluable tool in unraveling a number of mysteries. The longitudinal beam target asymmetry in {psi} photoproduction is a particularly sensitive probe of that content. It is explored here.

  5. Autonomous strange nonchaotic oscillations in a system of mechanical rotators

    NASA Astrophysics Data System (ADS)

    Jalnine, Alexey Yu.; Kuznetsov, Sergey P.

    2017-05-01

    We investigate strange nonchaotic self-oscillations in a dissipative system consisting of three mechanical rotators driven by a constant torque applied to one of them. The external driving is nonoscillatory; the incommensurable frequency ratio in vibrational-rotational dynamics arises due to an irrational ratio of diameters of the rotating elements involved. It is shown that, when losing stable equilibrium, the system can demonstrate two- or three-frequency quasi-periodic, chaotic and strange nonchaotic self-oscillations. The conclusions of the work are confirmed by numerical calculations of Lyapunov exponents, fractal dimensions, spectral analysis, and by special methods of detection of a strange nonchaotic attractor (SNA): phase sensitivity and analysis using rational approximation for the frequency ratio. In particular, SNA possesses a zero value of the largest Lyapunov exponent (and negative values of the other exponents), a capacitive dimension close to 2 and a singular continuous power spectrum. In general, the results of this work shed a new light on the occurrence of strange nonchaotic dynamics.

  6. Familiar-Strange: Teaching the Scripture as John Would Teach

    ERIC Educational Resources Information Center

    Ha, Tung-Chiew

    2014-01-01

    The Gospel of John teaches through telling the story of Jesus in light of the familiar Hebrew faith stories. It is an interpretive task that presents Jesus to his audience and teaches them adequate faith. John the Teacher skillfully uses narrative skills to create the familiar-strange effect in his storytelling. Each story is followed by a…

  7. Sampling High-Altitude and Stratified Mating Flights of Red Imported Fire Ant

    USDA-ARS?s Scientific Manuscript database

    With the exception of an airplane equipped with nets, no method has been developed that successfully samples red imported fire ant, Solenopsis invicta Buren, sexuals in mating/dispersal flights throughout their potential altitudinal trajectories. We developed and tested a method for sampling queens ...

  8. Similarity selection and the evolution of sex: revisiting the red queen.

    PubMed

    Agrawal, Aneil F

    2006-08-01

    For over 25 years, many evolutionary ecologists have believed that sexual reproduction occurs because it allows hosts to change genotypes each generation and thereby evade their coevolving parasites. However, recent influential theoretical analyses suggest that, though parasites can select for sex under some conditions, they often select against it. These models assume that encounters between hosts and parasites are completely random. Because of this assumption, the fitness of a host depends only on its own genotype ("genotypic selection"). If a host is even slightly more likely to encounter a parasite transmitted by its mother than expected by random chance, then the fitness of a host also depends on its genetic similarity to its mother ("similarity selection"). A population genetic model is presented here that includes both genotypic and similarity selection, allowing them to be directly compared in the same framework. It is shown that similarity selection is a much more potent force with respect to the evolution of sex than is genotypic selection. Consequently, similarity selection can drive the evolution of sex even if it is much weaker than genotypic selection with respect to fitness. Examination of explicit coevolutionary models reveals that even a small degree of mother-offspring parasite transmission can cause parasites to favor sex rather than oppose it. In contrast to previous predictions, the model shows that weakly virulent parasites are more likely to favor sex than are highly virulent ones. Parasites have figured prominently in discussions of the evolution of sex, but recent models suggest that parasites often select against sex rather than for it. With the inclusion of small and realistic exposure biases, parasites are much more likely to favor sex. Though parasites alone may not provide a complete explanation for sex, the results presented here expand the potential for parasites to contribute to the maintenance of sex rather than act against it.

  9. The red queen in the corn: agricultural weeds as models of rapid adaptive evolution.

    PubMed

    Vigueira, C C; Olsen, K M; Caicedo, A L

    2013-04-01

    Weeds are among the greatest pests of agriculture, causing billions of dollars in crop losses each year. As crop field management practices have changed over the past 12 000 years, weeds have adapted in turn to evade human removal. This evolutionary change can be startlingly rapid, making weeds an appealing system to study evolutionary processes that occur over short periods of time. An understanding of how weeds originate and adapt is needed for successful management; however, relatively little emphasis has been placed on genetically characterizing these systems. Here, we review the current literature on agricultural weed origins and their mechanisms of adaptation. Where possible, we have included examples that have been genetically well characterized. Evidence for three possible, non-mutually exclusive weed origins (from wild species, crop-wild hybrids or directly from crops) is discussed with respect to what is known about the microevolutionary signatures that result from these processes. We also discuss what is known about the genetic basis of adaptive traits in weeds and the range of genetic mechanisms that are responsible. With a better understanding of genetic mechanisms underlying adaptation in weedy species, we can address the more general process of adaptive evolution and what can be expected as we continue to apply selective pressures in agroecosystems around the world.

  10. The red queen in the corn: agricultural weeds as models of rapid adaptive evolution

    PubMed Central

    Vigueira, C C; Olsen, K M; Caicedo, A L

    2013-01-01

    Weeds are among the greatest pests of agriculture, causing billions of dollars in crop losses each year. As crop field management practices have changed over the past 12 000 years, weeds have adapted in turn to evade human removal. This evolutionary change can be startlingly rapid, making weeds an appealing system to study evolutionary processes that occur over short periods of time. An understanding of how weeds originate and adapt is needed for successful management; however, relatively little emphasis has been placed on genetically characterizing these systems. Here, we review the current literature on agricultural weed origins and their mechanisms of adaptation. Where possible, we have included examples that have been genetically well characterized. Evidence for three possible, non-mutually exclusive weed origins (from wild species, crop-wild hybrids or directly from crops) is discussed with respect to what is known about the microevolutionary signatures that result from these processes. We also discuss what is known about the genetic basis of adaptive traits in weeds and the range of genetic mechanisms that are responsible. With a better understanding of genetic mechanisms underlying adaptation in weedy species, we can address the more general process of adaptive evolution and what can be expected as we continue to apply selective pressures in agroecosystems around the world. PMID:23188175

  11. Clone mixtures and a pacemaker: new facets of Red-Queen theory and ecology.

    PubMed Central

    Sasaki, A; Hamilton, W D; Ubeda, F

    2002-01-01

    Host-parasite antagonistic interaction has been proposed as a potential agent to promote genetic polymorphism and to favour sex against asex, despite its twofold cost in reproduction. However, the host-parasite gene-for-gene dynamics often produce unstable cycles that tend to destroy genetic diversity. Here, we examine such diversity destroying coevolutionary dynamics of host and parasite, which is coupled through local or global migration, or both, between demes in a metapopulation structure. We show that, with global migration in the island model, peculiar out-of-phase islands spontaneously arise in the cluster of islands converging to a global synchrony. Such asynchrony induced by the 'pacemaker islands' serves to restore genetic variation. With increasing fraction of local migration, spots of asynchrony are converted into loci or foci of spiral and target patterns, whose rotating arms then cover the majority of demes. A multi-locus analogue of the model reproduces the same tendency toward asynchrony, and the condition arises for an advantage of asexual clones over their sexual counterpart when enough genetic diversity is maintained through metapopulation storage-migration serves as a cheap alternative to sex. PMID:11958707

  12. Postmating changes in cuticular chemistry and visual appearance in Ectatomma tuberculatum queens (Formicidae: Ectatomminae)

    NASA Astrophysics Data System (ADS)

    Hora, Riviane R.; Ionescu-Hirsh, Armin; Simon, Tovit; Delabie, Jacques; Robert, Jacques; Fresneau, Dominique; Hefetz, Abraham

    2008-01-01

    In the ectatommine ant Ectatomma tuberculatum, the visual appearance of queens changes after mating and ovarian development in that their cuticle turns from shiny to matte. In this study, we have shown that this change seems to be caused by 15-fold accumulation of hydrocarbons, in particular heptacosane that covers the multiple grooves present on the cuticular surface creating a wax coat in mated fully fertile queens. Analyses of the scrapped wax revealed that it is composed largely of heptacosane. Peak-by-peak comparison of the cuticular hydrocarbon (CHC) composition of mated, virgin with developed ovaries and virgin with nondeveloped ovaries revealed significant differences between the queen groups. Although the total amount of the CHC of virgin queens with developed ovaries was not higher than virgin queens that did not have developed ovaries, the composition showed a shift toward the mated queen. While it is possible that the large accumulation of hydrocarbons may give extra physical and chemical protection to queens, we propose that the switch in the relative abundance of heptacosane and nonacosane and perhaps of other components is indicative of being a mating and fertility cue. This is the first report in social insects where external chemical changes are accompanied by changes in visual appearance.

  13. Differential antennal proteome comparison of adult honeybee drone, worker and queen (Apis mellifera L.).

    PubMed

    Fang, Yu; Song, Feifei; Zhang, Lan; Aleku, Dereje Woltedji; Han, Bin; Feng, Mao; Li, Jianke

    2012-01-04

    To understand the olfactory mechanism of honeybee antennae in detecting specific volatile compounds in the atmosphere, antennal proteome differences of drone, worker and queen were compared using 2-DE, mass spectrometry and bioinformatics. Therefore, 107 proteins were altered their expressions in the antennae of drone, worker and queen bees. There were 54, 21 and 32 up-regulated proteins in the antennae of drone, worker and queen, respectively. Proteins upregulated in the drone antennae were involved in fatty acid metabolism, antioxidation, carbohydrate metabolism and energy production, protein folding and cytoskeleton. Proteins upregulated in the antennae of worker and queen bees were related to carbohydrate metabolism and energy production while molecular transporters were upregulated in the queen antennae. Our results explain the role played by the antennae of drone is to aid in perceiving the queen sexual pheromones, in the worker antennae to assist for food search and social communication and in the queen antennae to help pheromone communication with the worker and the drone during the mating flight. This first proteomic study significantly extends our understanding of honeybee olfactory activities and the possible mechanisms played by the antennae in response to various environmental, social, biological and biochemical signals.

  14. Diploid Male Production Results in Queen Death in the Stingless Bee Scaptotrigona depilis.

    PubMed

    Vollet-Neto, Ayrton; Oliveira, Ricardo C; Schillewaert, Sharon; Alves, Denise A; Wenseleers, Tom; Nascimento, Fabio S; Imperatriz-Fonseca, Vera L; Ratnieks, Francis L W

    2017-04-06

    As in most Hymenoptera, the eusocial stingless bees (Meliponini) have a complementary sex determination (CSD) system. When a queen makes a "matched mating" with a male that shares a CSD allele with her, half of their diploid offspring are diploid males rather than females. Matched mating imposes a cost, since diploid male production reduces the colony workforce. Hence, adaptations preventing the occurrence or attenuating its effects are likely to arise. Here we provide clear evidence that in the stingless bee Scaptotrigona depilis, the emergence of diploid males induces queen death, and this usually occurs within 10-20 days of the emergence of diploid male offspring from their pupae. Queens that have not made a matched mating die when introduced into a colony in which diploid males are emerging. This shows that the adult diploid males, and not the queen that has made a matched mating herself, are the proximate cause of queen death. Analysis of the cuticular hydrocarbon profiles of adult haploid and diploid males shows six compounds with significant differences. Moreover, the diploid and haploid males only acquire distinct cuticular hydrocarbon profiles 10 days after emergence. Our data shows that the timing of queen death occurs when the cuticular hydrocarbons of haploid and diploid males differ significantly, suggesting that these chemical differences could be used as cues or signals to trigger queen death.

  15. Small queens and big-headed workers in a monomorphic ponerine ant

    NASA Astrophysics Data System (ADS)

    Kikuchi, Tomonori; Miyazaki, Satoshi; Ohnishi, Hitoshi; Takahashi, Junichi; Nakajima, Yumiko; Tsuji, Kazuki

    2008-10-01

    Evolution of caste is a central issue in the biology of social insects. Comparative studies on their morphology so far suggest the following three patterns: (1) a positive correlation between queen worker size dimorphism and the divergence in reproductive ability between castes, (2) a negative correlation among workers between morphological diversity and reproductive ability, and (3) a positive correlation between queen worker body shape difference and the diversity in worker morphology. We conducted morphological comparisons between castes in Pachycondyla luteipes, workers of which are monomorphic and lack their reproductive ability. Although the size distribution broadly overlapped, mean head width, head length, and scape length were significantly different between queens and workers. Conversely, in eye length, petiole width, and Weber’s length, the size differences were reversed. The allometries (head length/head width, scape length/head width, and Weber’s length/head width) were also significantly different between queens and workers. Morphological examinations showed that the body shape was different between queens and workers, and the head part of workers was disproportionately larger than that of queens. This pattern of queen worker dimorphism is novel in ants with monomorphic workers and a clear exception to the last pattern. This study suggests that it is possible that the loss of individual-level selection, the lack of reproductive ability, influences morphological modification in ants.

  16. Queen execution increases relatedness among workers of the invasive Argentine ant, Linepithema humile.

    PubMed

    Inoue, Maki N; Ito, Fuminori; Goka, Koichi

    2015-09-01

    Polygyny in social insects can greatly reduce within-nest genetic relatedness. In polygynous ant species, potential rival queens in colonies with multiple queens are often executed by other queens, workers, or both. The Argentine ant, Linepithema humile, native to South America, forms a "supercolony" that is composed of a large number of nests and is considered to contribute to the ant's invasion success. Currently, four mutually antagonistic supercolonies are contiguously distributed within a small area of Japan. Here, we analyzed the genetic structure and relatedness within and among the four supercolonies using microsatellite markers to clarify how L. humile maintains its supercoloniality. The results of AMOVA and BASP, the F ST values, and the existence of several private alleles indicated that the L. humile population in the Kobe area had a characteristic genetic structure. Within a given supercolony, there was significant genetic differentiation (F ST) among workers collected in May and those collected in September. The significant deviation from Hardy-Weinberg equilibrium increased, and the relatedness among workers significantly increased from May to September in all supercolonies. This result suggested that the supercolonies replaced old queens with new ones during the reproductive season, thus supporting the plausibility of queen execution. From the perspective of kin selection, workers collectively eliminate queens, thereby increasing their own inclusive fitness. Restricted gene flow among supercolonies, together with mating with sib and queen execution, could help to maintain the unique social structure of L. humile, the distribution of which is expanding worldwide.

  17. A conserved class of queen pheromones? Re-evaluating the evidence in bumblebees (Bombus impatiens)

    PubMed Central

    Amsalem, Etya; Orlova, Margarita; Grozinger, Christina M.

    2015-01-01

    The regulation of reproductive division of labour is a key component in the evolution of social insects. Chemical signals are important mechanisms to regulate worker reproduction, either as queen-produced pheromones that coercively inhibit worker reproduction or as queen signals that honestly advertise her fecundity. A recent study suggested that a conserved class of hydrocarbons serve as queen pheromones across three independent origins of eusociality. In bumblebees (Bombus terrestris), pentacosane (C25) was suggested to serve as a queen pheromone. Here, we repeat these studies using a different species of bumblebee (Bombus impatiens) with a more controlled experimental design. Instead of dequeened colonies, we used same-aged, three-worker queenless groups comprising either experienced or naive workers (with/without adult exposure to queen pheromone). We quantified three hydrocarbons (C23, C25 and C27) on the cuticular surfaces of females and tested their effects on the two worker types. Our results indicate differences in responses of naive and experienced workers, genetic effects on worker reproduction, and general effects of hydrocarbons and duration of egg laying on ovary resorption rates. However, we found no evidence to support the theory that a conserved class of hydrocarbons serve as queen pheromones or queen signals in Bombus impatiens. PMID:26490791

  18. A conserved class of queen pheromones? Re-evaluating the evidence in bumblebees (Bombus impatiens).

    PubMed

    Amsalem, Etya; Orlova, Margarita; Grozinger, Christina M

    2015-10-22

    The regulation of reproductive division of labour is a key component in the evolution of social insects. Chemical signals are important mechanisms to regulate worker reproduction, either as queen-produced pheromones that coercively inhibit worker reproduction or as queen signals that honestly advertise her fecundity. A recent study suggested that a conserved class of hydrocarbons serve as queen pheromones across three independent origins of eusociality. In bumblebees (Bombus terrestris), pentacosane (C25) was suggested to serve as a queen pheromone. Here, we repeat these studies using a different species of bumblebee (Bombus impatiens) with a more controlled experimental design. Instead of dequeened colonies, we used same-aged, three-worker queenless groups comprising either experienced or naive workers (with/without adult exposure to queen pheromone). We quantified three hydrocarbons (C23, C25 and C27) on the cuticular surfaces of females and tested their effects on the two worker types. Our results indicate differences in responses of naive and experienced workers, genetic effects on worker reproduction, and general effects of hydrocarbons and duration of egg laying on ovary resorption rates. However, we found no evidence to support the theory that a conserved class of hydrocarbons serve as queen pheromones or queen signals in Bombus impatiens. © 2015 The Author(s).

  19. Queen Alexandra Range 93148: A new type of pyroxene pallasite?

    NASA Astrophysics Data System (ADS)

    Floss, Christine

    2002-08-01

    Trace elements, including the rare earth elements, were measured in olivine and orthopyroxene from Queen Alexandra Range (QUE) 93148, and in olivine from two main group pallasites, Springwater and Mount Vernon. Although QUE 93148 was originally classified as a lodranite, a variety of data including oxygen isotopic compositions (Goodrich and Righter, 2000), preclude a genetic relationship with the acapulcoites/lodranites. Incompatible trace element (e.g., Ti, Zr) distributions in orthopyroxene do indicate large amounts of melting and are consistent with the ultramafic assemblage observed in this meteorite. Trace element abundances in olivine are consistent with suggestions that QUE 93148 may be related to the main group pallasites (Goodrich and Righter, 2000), although there are some inconsistencies. Its trace element distributions are most like those of the pyroxene pallasites, suggesting that it may have formed in a similar manner. QUE 93148 may represent a new type of pyroxene pallasite with links to the main group pallasites.

  20. Complete uterine prolapse without uterine mucosal eversion in a queen.

    PubMed

    Bigliardi, E; Di Ianni, F; Parmigiani, E; Cantoni, A M; Bresciani, C

    2014-04-01

    A five-year-old female cat weighing 3 kg was presented by the owner after noticing a large pink, bilobed mass protruding through the vulva during labour. The cat was in good condition, with appropriate lactation, and the newborn kittens were nursing normally. The uterus was not reverted or invaginated at examination, and there was rupture of the mesovarium, mesometrium and uterine-vaginal connection around the cervix. Manual reduction of the prolapsed uterus was not possible because of torn ligaments. A coeliotomy was performed to remove the ovaries, and the apex of the uterine horns was passed by the vaginal route. The remaining part of the mesometrium was disconnected, and the prolapsed uterus was removed. The queen and kittens were discharged from the hospital on the second day after surgery. An unusual feature of this case is that the prolapse was complete, without eversion of any part of the uterus through a vaginal tear.

  1. South Pole Queen Maud Land Traverses, 1964-68 (Invited)

    NASA Astrophysics Data System (ADS)

    Bentley, C. R.

    2009-12-01

    Between early December, 1964, and late January, 1968, the three-part "South Pole Queen Maud Land Traverse" (SPQMLT), supported by the U.S. Antarctic Research Program (USARP), explored the previously unexamined interior of Queen Maud Land, making measurements of surface height and slope, surface mass balance, bore-hole temperatures, ice thickness, seismic wave velocities in and below the ice, gravity, and magnetics. The traverse followed a zigzag, space-filling route between Pole Station, the abandoned Pole of Relative Inaccessibility station, and Plateau Station on the east and roughly the Greenwich Meridian on the west. The traverse equipment featured two large Model 843 Tucker Sno-Cats, designed and built especially for work on the high East Antarctic plateau. Unfortunately, for programmatic reasons a planned 4th season to drive the Sno-Cats back to Pole Station could not be supported, so they were permanently abandoned at the end of the third traverse, at 78° 42.2'S, 6° 52'W. The SPQMLT was remarkable not only for working in a previously unexplored area, but also for the introduction of several new techniques to Antarctic traverse studies, two of which, radar sounding and determination of accumulation rates using a dated radioactive fallout horizon, were major advances that will be discussed by other authors in this session. In this presentation I will discuss the seismic, gravity, and magnetic observations and what they suggest about the character of the underlying terrain. Because of the pronounced differences in route pattern between the SPQMLT and the recent Troll-Pole-Troll traverses the data will be strongly complementary. From SPQMLT only the positions and surface heights are not up to modern standards of accuracy, but the former are adequate for regional studies and the latter have all been superseded by satellite radar and laser altimetry anyway.

  2. Asymmetric Dispersal and Colonization Success of Amazonian Plant-Ants Queens

    PubMed Central

    Bruna, Emilio M.; Izzo, Thiago J.; Inouye, Brian D.; Uriarte, Maria; Vasconcelos, Heraldo L.

    2011-01-01

    Background The dispersal ability of queens is central to understanding ant life-history evolution, and plays a fundamental role in ant population and community dynamics, the maintenance of genetic diversity, and the spread of invasive ants. In tropical ecosystems, species from over 40 genera of ants establish colonies in the stems, hollow thorns, or leaf pouches of specialized plants. However, little is known about the relative dispersal ability of queens competing for access to the same host plants. Methodology/Principal Findings We used empirical data and inverse modeling—a technique developed by plant ecologists to model seed dispersal—to quantify and compare the dispersal kernels of queens from three Amazonian ant species that compete for access to host-plants. We found that the modal colonization distance of queens varied 8-fold, with the generalist ant species (Crematogaster laevis) having a greater modal distance than two specialists (Pheidole minutula, Azteca sp.) that use the same host-plants. However, our results also suggest that queens of Azteca sp. have maximal distances that are four-sixteen times greater than those of its competitors. Conclusions/Significance We found large differences between ant species in both the modal and maximal distance ant queens disperse to find vacant seedlings used to found new colonies. These differences could result from interspecific differences in queen body size, and hence wing musculature, or because queens differ in their ability to identify potential host plants while in flight. Our results provide support for one of the necessary conditions underlying several of the hypothesized mechanisms promoting coexistence in tropical plant-ants. They also suggest that for some ant species limited dispersal capability could pose a significant barrier to the rescue of populations in isolated forest fragments. Finally, we demonstrate that inverse models parameterized with field data are an excellent means of quantifying the

  3. Development of the honey bee gut microbiome throughout the queen-rearing process.

    PubMed

    Tarpy, David R; Mattila, Heather R; Newton, Irene L G

    2015-05-01

    The European honey bee (Apis mellifera) is used extensively to produce hive products and for crop pollination, but pervasive concerns about colony health and population decline have sparked an interest in the microbial communities that are associated with these important insects. Currently, only the microbiome of workers has been characterized, while little to nothing is known about the bacterial communities that are associated with queens, even though their health and proper function are central to colony productivity. Here, we provide a large-scale analysis of the gut microbiome of honey bee queens during their developmental trajectory and through the multiple colonies that host them as part of modern queen-rearing practices. We found that queen microbiomes underwent a dramatic shift in size and composition as they aged and encountered different worker populations and colony environments. Queen microbiomes were dominated by enteric bacteria in early life but were comprised primarily of alphaproteobacteria at maturity. Furthermore, queen gut microbiomes did not reflect those of the workers who tended them and, indeed, they lacked many of the bacteria that are considered vital to workers. While worker gut microbiotas were consistent across the unrelated colony populations sampled, the microbiotas of the related queens were highly variable. Bacterial communities in mature queen guts were similar in size to those of mature workers and were characterized by dominant and specific alphaproteobacterial strains known to be associated with worker hypopharyngeal glands. Our results suggest a model in which queen guts are colonized by bacteria from workers' glands, in contrast to routes of maternal inoculation for other animal microbiomes. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  4. New insights into honey bee (Apis mellifera) pheromone communication. Is the queen mandibular pheromone alone in colony regulation?

    PubMed Central

    2010-01-01

    Background In social insects, the queen is essential to the functioning and homeostasis of the colony. This influence has been demonstrated to be mediated through pheromone communication. However, the only social insect for which any queen pheromone has been identified is the honey bee (Apis mellifera) with its well-known queen mandibular pheromone (QMP). Although pleiotropic effects on colony regulation are accredited to the QMP, this pheromone does not trigger the full behavioral and physiological response observed in the presence of the queen, suggesting the presence of additional compounds. We tested the hypothesis of a pheromone redundancy in honey bee queens by comparing the influence of queens with and without mandibular glands on worker behavior and physiology. Results Demandibulated queens had no detectable (E)-9-oxodec-2-enoic acid (9-ODA), the major compound in QMP, yet they controlled worker behavior (cell construction and queen retinue) and physiology (ovary inhibition) as efficiently as intact queens. Conclusions We demonstrated that the queen uses other pheromones as powerful as QMP to control the colony. It follows that queens appear to have multiple active compounds with similar functions in the colony (pheromone redundancy). Our findings support two hypotheses in the biology of social insects: (1) that multiple semiochemicals with synonymous meaning exist in the honey bee, (2) that this extensive semiochemical vocabulary exists because it confers an evolutionary advantage to the colony. PMID:20565874

  5. Bacterial and protozoal causes of pregnancy loss in the bitch and queen.

    PubMed

    Pretzer, S D

    2008-08-01

    Several bacterial species have been implicated in canine and feline pregnancy loss. Brucella canis is one of the more important bacterial infectious agents that cause pregnancy loss in the bitch. Brucella has been documented in the queen but in general infectious abortion from bacteria and protozoal agents is uncommon in the species. Protozoal causes of pregnancy loss in the bitch and queen are less common than in other species. Etiology, clinical signs, diagnosis and treatment of bacterial and protozoal causes of pregnancy loss in the bitch and queen are reviewed. Veterinary practitioners should be aware that many of these organisms have zoonotic potential.

  6. Queen pheromones modulate DNA methyltransferase activity in bee and ant workers

    PubMed Central

    Holman, Luke; Trontti, Kalevi; Helanterä, Heikki

    2016-01-01

    DNA methylation is emerging as an important regulator of polyphenism in the social insects. Research has concentrated on differences in methylation between queens and workers, though we hypothesized that methylation is involved in mediating other flexible phenotypes, including pheromone-dependent changes in worker behaviour and physiology. Here, we find that exposure to queen pheromone affects the expression of two DNA methyltransferase genes in Apis mellifera honeybees and in two species of Lasius ants, but not in Bombus terrestris bumblebees. These results suggest that queen pheromones influence the worker methylome, pointing to a novel proximate mechanism for these key social signals. PMID:26814223

  7. Queen pheromones modulate DNA methyltransferase activity in bee and ant workers.

    PubMed

    Holman, Luke; Trontti, Kalevi; Helanterä, Heikki

    2016-01-01

    DNA methylation is emerging as an important regulator of polyphenism in the social insects. Research has concentrated on differences in methylation between queens and workers, though we hypothesized that methylation is involved in mediating other flexible phenotypes, including pheromone-dependent changes in worker behaviour and physiology. Here, we find that exposure to queen pheromone affects the expression of two DNA methyltransferase genes in Apis mellifera honeybees and in two species of Lasius ants, but not in Bombus terrestris bumblebees. These results suggest that queen pheromones influence the worker methylome, pointing to a novel proximate mechanism for these key social signals. © 2016 The Author(s).

  8. Parity Violating Electron Scattering and Strangeness in the Nucleon

    SciTech Connect

    Maas, Frank E.

    2008-10-13

    A measurement of the weak form factor of the proton allows a flavor separation of the strangeness contribution to the electromagnetic form factors. The weak form factor is accessed experimentally by the measurement of a parity violating (PV) asymmetry in the scattering of polarized electrons on unpolarized protons. An extended experimental program to measure these parity violating asymmetries has been performed and is going on at different accelerators. After the first round of experiments allowing a separation of the strangeness form factors G{sub E}{sup s} and G{sub M}{sup s} at a Q{sup 2}-value of 0.1 (GeV/c){sup 2}, new, preliminary results have been achieved at 0.23 (GeV/c){sup 2}.

  9. Strange quintessence star in Krori-Barua spacetime

    NASA Astrophysics Data System (ADS)

    Bhar, Piyali

    2015-04-01

    In the present paper a new model of a compact star is obtained by utilizing the Krori-Barua (KB) ansatz [Krori and Barua in J. Phys. A, Math. Gen. 8:508, 1975] in the presence of a quintessence field characterized by a parameter ω q with . The obtained model of strange stars is singularity free and satisfies all the physical requirements. Our model is stable as well as it is in static equilibrium. The numerical values of the mass of the strange stars 4U1820-30 (radius=10 km), SAX J1808.4-3658(SS1) (radius=7.07 km) and Her X-1 (radius=7.7 km) calculated from our model are very close to the standard data. The interior solution is matched to the exterior Schwarzschild spacetime in the presence of a thin shell where a negative surface pressure is needed to keep the thin shell from collapsing.

  10. Strange attractors in weakly turbulent Couette-Taylor flow

    NASA Technical Reports Server (NTRS)

    Brandstater, A.; Swinney, Harry L.

    1987-01-01

    An experiment is conducted on the transition from quasi-periodic to weakly turbulent flow of a fluid contained between concentric cylinders with the inner cylinder rotating and the outer cylinder at rest. Power spectra, phase-space portraits, and circle maps obtained from velocity time-series data indicate that the nonperiodic behavior observed is deterministic, that is, it is described by strange attractors. Various problems that arise in computing the dimension of strange attractors constructed from experimental data are discussed and it is shown that these problems impose severe requirements on the quantity and accuracy of data necessary for determining dimensions greater than about 5. In the present experiment the attractor dimension increases from 2 at the onset of turbulence to about 4 at a Reynolds number 50-percent above the onset of turbulence.

  11. Multi-strangeness production in hadron induced reactions

    NASA Astrophysics Data System (ADS)

    Gaitanos, T.; Moustakidis, Ch.; Lalazissis, G. A.; Lenske, H.

    2016-10-01

    We discuss in detail the formation and propagation of multi-strangeness particles in reactions induced by hadron beams relevant for the forthcoming experiments at FAIR. We focus the discussion on the production of the decuplet-particle Ω and study for the first time the production and propagation mechanism of this heavy hyperon inside hadronic environments. The transport calculations show the possibility of Ω-production in the forthcoming P ‾ANDA-experiment, which can be achieved with measurable probabilities using high-energy secondary Ξ-beams. We predict cross sections for Ω-production. The theoretical results are important in understanding the hyperon-nucleon and, in particular, the hyperon-hyperon interactions also in the high-strangeness sector. We emphasize the importance of our studies for the research plans at FAIR.

  12. Fast pulsars, strange stars: An opportunity in radio astronomy

    SciTech Connect

    Glendenning, N.K.

    1990-07-15

    The world's data on radio pulsars is not expected to represent the underlying pulsar population because of a search bias against detection of short periods, especially below 1 ms. Yet pulsars in increasing numbers with periods right down to this limit have been discovered suggesting that there may be even shorter ones. If pulsars with periods below 1/2 ms were found, the conclusion that the confined hadronic phase of nucleons and nuclei is only metastable would be almost inescapable. The plausible ground state in that event is the deconfined phase of (3-flavor) strange-quark-matter. From the QCD energy scale this is as likely a ground state as the confined phase. We show that strange matter as the ground state is not ruled out by any known fact, and most especially not by the fact that the universe is in the confined phase. 136 refs.

  13. Strange attractors in weakly turbulent Couette-Taylor flow

    NASA Technical Reports Server (NTRS)

    Brandstater, A.; Swinney, Harry L.

    1987-01-01

    An experiment is conducted on the transition from quasi-periodic to weakly turbulent flow of a fluid contained between concentric cylinders with the inner cylinder rotating and the outer cylinder at rest. Power spectra, phase-space portraits, and circle maps obtained from velocity time-series data indicate that the nonperiodic behavior observed is deterministic, that is, it is described by strange attractors. Various problems that arise in computing the dimension of strange attractors constructed from experimental data are discussed and it is shown that these problems impose severe requirements on the quantity and accuracy of data necessary for determining dimensions greater than about 5. In the present experiment the attractor dimension increases from 2 at the onset of turbulence to about 4 at a Reynolds number 50-percent above the onset of turbulence.

  14. A Strange Supernova with a Gamma-Ray Burst

    NASA Astrophysics Data System (ADS)

    1998-10-01

    Important Observations with La Silla Telescopes Several articles appear today in the scientific journal Nature about the strange supernova SN 1998bw that exploded earlier this year in the spiral galaxy ESO184-G82 . These studies indicate that this event was linked to a Gamma-Ray Burst and may thus provide new insights into this elusive phenomenon. Important observations of SN 1998bw have been made with several astronomical telescopes at the ESO La Silla Observatory by some of the co-authors of the Nature articles [1]. The measurements at ESO will continue during the next years. The early observations On April 25, the BeppoSAX satellite detected a Gamma-Ray Burst from the direction of the constellation Telescopium, deep in the southern sky. Although there is now general consensus that they originate in very distant galaxies, the underlying physical causes of these events that release great amounts of energy within seconds are still puzzling astronomers. Immediately after reports about the April 25 Burst had been received, astronomers at La Silla took some images of the sky region where the gamma-rays were observed as a "Target of Opportunity" (ToO) programme. The aim was to check if the visual light of one of the objects in the field had perhaps brightened when compared to exposures made earlier. This would then provide a strong indication of the location of the Gamma-Ray Burst. The digital exposures were transferred to the Italian/Dutch group around BeppoSax that had requested these ToO observations. Astronomers of this group quickly noticed a new, comparatively bright star, right on the arm of a small spiral galaxy. This galaxy was first catalogued in the 1970's during the ESO/Uppsala Survey of the Southern Sky and received the designation ESO184-G82 . It is located at a distance of about 140 million light-years. SN 1998bw ESO PR Photo 39a/98 ESO PR Photo 39a/98 [Preview - JPEG: 800 x 963 pix - 592k] [High-Res - JPEG: 3000 x 3612 pix - 4.1Mb] ESO PR Photo 39b/98

  15. Strange hadron production at SIS energies: an update from HADES

    NASA Astrophysics Data System (ADS)

    Lorenz, M.; Adamczewski-Musch, J.; Arnold, O.; Atomssa, E. T.; Behnke, C.; Berger-Chen, J. C.; Biernat, J.; Blanco, A.; Blume, C.; Böhmer, M.; Bordalo, P.; Chernenko, S.; Deveaux, C.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Fonte, P.; Franco, C.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gill, K.; Golubeva, M.; Guber, F.; Gumberidze, M.; Harabasz, S.; Hennino, T.; Hlavac, S.; Höhne, C.; Holzmann, R.; Ierusalimov, A.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Kardan, B.; Koenig, I.; Koenig, W.; Kolb, B. W.; Korcyl, G.; Kornakov, G.; Kotte, R.; Krása, A.; Krebs, E.; Kuc, G.; Kugler, A.; Kunz, T.; Kurepin, A.; Kurilkin, A.; Kurilkin, P.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Lopes, L.; Mahmoud, T.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michel, J.; Müntz, C.; Münzer, R.; Naumann, L.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Petousis, V.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Rehnisch, L.; Reshetin, A.; Rost, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Scheib, T.; Schmidt-Sommerfeld, K.; Schuldes, H.; Sellheim, P.; Siebenson, J.; Silva, L.; Sobolev, Yu. G.; Spataro, S.; Ströbele, H.; Stroth, J.; Strzempek, P.; Sturm, C.; Svoboda, O.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Wendisch, C.; Wirth, J.; Wüstenfeld, J.; Zanevsky, Y.; Zumbruch, P.

    2016-01-01

    We present and discuss recent experimental activities of the HADES collaboration on open and hidden strangeness production close or below the elementary NN threshold. Special emphasis is put on the feed-down from ϕ mesons to antikaons, the presence of the Ξ- excess in cold nuclear matter and the comparison of statistical model rates to elementary p+p data. The implications for the interpretation of heavy-ion data are discussed as well.

  16. Strangeness-conserving hadronic parity violation at low energies

    NASA Astrophysics Data System (ADS)

    Liu, C.-P.

    2007-05-01

    The parity-violating nucleaon interacton is the key to understanding the strangeness-conserving hadronic weak interaction at low energies. In this brief talk, I review the past accomplishement in and current status of this subject, and outline a new joint effort between experiment and theory that that tries to address the potential problems in the past by focusing on parity violation in few-nucleon systems and using the language of effective field theory.

  17. A useful approximate isospin equality for charmless strange B decays.

    SciTech Connect

    Lipkin, H. J.; High Energy Physics; Weizmann Inst. of Science; Aviv Univ.

    1999-01-01

    A useful inequality is obtained if charmless strange B decays are assumed to be dominated by a {Delta}l=0 transition like that from the gluonic penguin diagram and the contributions of all other diagrams including the tree, electroweak penguin and annihilation diagrams are small but not negligible. The interference contributions which are linear in these other amplitudes are included but the direct contributions which are quadratic are neglected.

  18. The Strange Quark Polarisation from Charged Kaon Production on Deuterons

    SciTech Connect

    Windmolders, R.

    2009-08-04

    The strange quark helicity distribution {delta}s(x) is derived at LO from the semi-inclusive and inclusive spin asymmetries measured by the COMPASS experiment at CERN. The significance of the results is found to depend critically on the ratio of the s-bar and u quark fragmentation functions into kaons {integral}D{sub s-bar}{sup K+}(z)dz/{integral}D{sub u}{sup K+}(z)dz.

  19. Strangeness Photoproduction at the BGO-OD Experiment

    NASA Astrophysics Data System (ADS)

    Jude, T. C.; Alef, S.; Bayadilov, D.; Beck, R.; Becker, M.; Bella, A.; Bielefeldt, P.; Boese, S.; Braghieri, A.; Brinkmann, K.; Cole, P.; Curciarello, F.; De Leo, V.; Di Salvo, R.; Dutz, H.; Elsner, D.; Fantini, A.; Freyermuth, O.; Friedrich, S.; Frommberger, F.; Ganenko, V.; Gervino, G.; Ghio, F.; Giardina, G.; Goertz, S.; Gridnev, A.; Gutz, E.; Hammann, D.; Hannappel, J.; Hartmann, P.; Hillert, W.; Ignatov, A.; Jahn, R.; Joosten, R.; Klein, F.; Koop, K.; Krusche, B.; Lapik, A.; Levi Sandri, P.; Lopatin, I. V.; Mandaglio, G.; Messi, F.; Messi, R.; Metag, V.; Moricciani, D.; Mushkarenkov, A.; Nanova, M.; Nedorezov, V.; Novinskiy, D.; Pedroni, P.; Reitz, B.; Romaniuk, M.; Rostomyan, T.; Rudnev, N.; Scheluchin, G.; Schmieden, H.; Stugelev, A.; Sumachev, V.; Tarakanov, V.; Vegna, V.; Walther, D.; Watts, D.; Zaunick, H.; Zimmermann, T.

    BGO-OD is a newly commissioned experiment to investigate the internal structure of the nucleon, using an energy tagged bremsstrahlung photon beam at the ELSA electron facility. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. BGO-OD is ideal for investigating meson photoproduction. The extensive physics programme for open strangeness photoproduction is introduced, and preliminary analysis presented.

  20. Bulk viscosity of strange quark matter: Urca versus nonleptonic processes

    SciTech Connect

    Sa'd, Basil A.; Shovkovy, Igor A.; Rischke, Dirk H.

    2007-06-15

    A general formalism for calculating the bulk viscosity of strange quark matter is developed. Contrary to the common belief that the nonleptonic processes alone give the dominant contribution to the bulk viscosity, the inclusion of the Urca processes is shown to play an important role at intermediate densities when the characteristic r-mode oscillation frequencies are not too high. The interplay of nonleptonic and Urca processes is analyzed in detail.

  1. A realistic model for charged strange quark stars

    NASA Astrophysics Data System (ADS)

    Thirukkanesh, S.; Ragel, F. C.

    2017-01-01

    We report a general approach to solve an Einstein-Maxwell system to describe a static spherically symmetric anisotropic strange matter distribution with linear equation of state in terms of two generating functions. It is examined by choosing Tolmann IV type potential for one of the gravitational potentials and a physically reasonable choice for the electric field. Hence, the generated model satisfies all the required major physical properties of a realistic star. The effect of electric charge on physical properties is highlighted.

  2. Ant queens adjust egg fertilization to benefit from both sexual and asexual reproduction.

    PubMed

    Aron, S; Timmermans, I; Pearcy, M

    2011-08-23

    An enduring problem in evolutionary biology is the near ubiquity of sexual reproduction despite the inherent cost of transmitting only half the parent's genes to progeny. Queens of some ant species circumvent this cost by using selectively both sexual reproduction and parthenogenesis: workers arise from fertilized eggs, while new queens are produced by parthenogenesis. We show that queens of the ant Cataglyphis cursor maximize the transmission rate of their genes by regulating the proportion of fertilized and parthenogenetic eggs laid over time. Parthenogenetic offspring are produced in early spring, when workers raise the brood into sexuals. After the mating period, queens lay mostly fertilized eggs that will be reared as the non-reproductive caste. This journal is © 2011 The Royal Society

  3. Impact of imidacloprid on new queens of imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae).

    PubMed

    Wang, Lei; Zeng, Ling; Chen, Jian

    2015-12-08

    Neonicotinoid insecticides are commonly used in managing pest insects, including the imported fire ant, Solenopsis invicta Buren. There is increasing evidence that neonicotinoid insecticides at sublethal concentrations have profound effects on social insects. However, the sublethal effect of neonicotinoids on S. invicta has never been investigated. In this study, the newly mated queens were fed with water containing 0.01 or 0.25 μg/ml imidacloprid. Imidacloprid at both concentrations did not cause any increase in queen mortality during the founding stage; however, it significantly reduced queens' brood tending ability. In the 0.25 μg/ml imidacloprid treatment, the time to larval emergence was significantly delayed and no pupae or adult workers were produced. This study provides clear evidence that imidacloprid at sublethal concentrations has a significant detrimental impact on S. invicta queens and the development of incipient colonies.

  4. Ant queens adjust egg fertilization to benefit from both sexual and asexual reproduction

    PubMed Central

    Aron, S.; Timmermans, I.; Pearcy, M.

    2011-01-01

    An enduring problem in evolutionary biology is the near ubiquity of sexual reproduction despite the inherent cost of transmitting only half the parent's genes to progeny. Queens of some ant species circumvent this cost by using selectively both sexual reproduction and parthenogenesis: workers arise from fertilized eggs, while new queens are produced by parthenogenesis. We show that queens of the ant Cataglyphis cursor maximize the transmission rate of their genes by regulating the proportion of fertilized and parthenogenetic eggs laid over time. Parthenogenetic offspring are produced in early spring, when workers raise the brood into sexuals. After the mating period, queens lay mostly fertilized eggs that will be reared as the non-reproductive caste. PMID:21307046

  5. Queen Charlotte basin off western Canada may hold oil, gas potential

    SciTech Connect

    Lyatsky, H.V. ); Haggart, J.W. )

    1992-08-24

    The Queen Charlotte basin is a large Tertiary tectonic feature on the west coast of Canada. Over the last few decades it has repeatedly been the target of petroleum exploration. A considerable amount of drilling was carried out in the 1950s and 1960s both on Queen Charlotte Islands and offshore. Six wells were drilled in Hecate strait and two in Queen Charlotte sound. The maximum depth reached was 15,656 ft. A moratorium on offshore drilling is in effect for environmental reasons. If it is lifted, a new surge of exploration activity is anticipated. To prepare for that activity, the Geological Survey of Canada started the Queen Charlotte Basin Frontier Geoscience Program, with the principal objective of assessing the petroleum potential of Canada's northern west coast. In this article, the authors discuss the petroleum geology of the region and highlight what we believe are new exploration opportunities.

  6. Virgin ant queens mate with their own sons to avoid failure at colony foundation

    NASA Astrophysics Data System (ADS)

    Schmidt, Christine Vanessa; Frohschammer, Sabine; Schrempf, Alexandra; Heinze, Jürgen

    2014-01-01

    Mother-son mating (oedipal mating) is practically non-existent in social Hymenoptera, as queens typically avoid inbreeding, mate only early in life and do not mate again after having begun to lay eggs. In the ant genus Cardiocondyla mating occurs among sib in the natal nests. Sex ratios are extremely female-biased and young queens face the risk of remaining without mating partners. Here, we show that virgin queens of Cardiocondyla argyrotricha produce sons from their own unfertilized eggs and later mate with them to produce female offspring from fertilized eggs. Oedipal mating may allow C. argyrotricha queens to found new colonies when no mating partners are available and thus maintains their unusual life history combining monogyny, mating in the nest, and low male production. Our result indicates that a trait that sporadically occurs in solitary haplodiploid animals may evolve also in social Hymenoptera under appropriate ecological and social conditions.

  7. Mimicry of queen Dufour's gland secretions by workers of Apis mellifera scutellata and A. m. capensis.

    PubMed

    Sole, Catherine L; Kryger, Per; Hefetz, Abraham; Katzav-Gozansky, Tamar; Crewe, Robin M

    2002-12-01

    The development of the Dufour's gland of workers of the two honey bee races Apis mellifera scutellata and A. m. capensis was measured. The Dufour's glands of A. m. capensis workers were longer and increased in length more rapidly than the glands of workers of A. m. scutellata at comparable ages. Analysis of the Dufour's gland secretions of workers and queens of both races revealed that there were caste and racial differences. Secretions of queenright A. m. scutellata workers were dominated by a series of long-chain hydrocarbons. In contrast the secretions of the A. m. capensis workers both under queenright and queenless conditions were a mixture of hydrocarbons and wax-type esters, as were those of queens. Multivariate analysis of the secretion profiles indicated that laying workers of both races mimic queens. The secretions of the A. m. capensis laying workers mimicked queen secretions most closely, enabling them to act as successful social parasites.

  8. Mimicry of queen Dufour's gland secretions by workers of Apis mellifera scutellata and A. m. capensis

    NASA Astrophysics Data System (ADS)

    Sole, Catherine; Kryger, Per; Hefetz, Abraham; Katzav-Gozansky, Tamar; Crewe, Robin

    2002-10-01

    The development of the Dufour's gland of workers of the two honey bee races Apis mellifera scutellata and A. m. capensis was measured. The Dufour's glands of A. m. capensis workers were longer and increased in length more rapidly than the glands of workers of A. m. scutellata at comparable ages. Analysis of the Dufour's gland secretions of workers and queens of both races revealed that there were caste and racial differences. Secretions of queenright A. m. scutellata workers were dominated by a series of long-chain hydrocarbons. In contrast the secretions of the A. m. capensis workers both under queenright and queenless conditions were a mixture of hydrocarbons and wax-type esters, as were those of queens. Multivariate analysis of the secretion profiles indicated that laying workers of both races mimic queens. The secretions of the A. m. capensis laying workers mimicked queen secretions most closely, enabling them to act as successful social parasites.

  9. Chemical recognition of partner plant species by foundress ant queens in Macaranga-Crematogaster myrmecophytism.

    PubMed

    Inui, Y; Itioka, T; Murase, K; Yamaoka, R; Itino, T

    2001-10-01

    The partnership in the Crematogaster-Macaranga ant-plant interaction is highly species-specific. Because a mutualistic relationship on a Macaranga plant starts with colonization by a foundress queen of a partner Crematogaster species, we hypothesized that the foundress queens select their partner plant species by chemical recognition. We tested this hypothesis with four sympatric Macaranga species and their Crematogaster plant-ant species. We demonstrated that foundress Crematogaster queens can recognize their partner Macaranga species by contact with the surface of the seedlings, that they can recognize compounds from the stem surface of seedlings of their partner plant species, and that the gas chromatographic profiles are characteristic of the plant species. These findings support the hypothesis that foundress queens of the Crematogaster plant-ant species select their partner Macaranga species by recognizing nonvolatile chemical characteristics of the stem surfaces of seedlings.

  10. Quark-hadron phase transition and strangeness conservation constraints

    NASA Astrophysics Data System (ADS)

    Saeed-Uddin

    1999-01-01

    The implications of the strangeness conservation in a hadronic resonance gas (HRG) on the expected phase transition to the quark gluon plasma (QGP) are investigated. It is assumed that under favourable conditions a first order hadron-quark matter phase transition may occur in the hot hadronic matter such as those produced in the ultra-relativistic heavy-ion collisions at CERN and BNL. It is however shown that the criteria of strict strangeness conservation in the HRG may not permit the occurrence of a strict first order equilibrium quark-hadron phase transition unlike a previous study. This emerges as a consequence of the application of a realistic equation of state (EOS) for the HRG and QGP phases, which account for the finite-size effect arising from the short range hard-core hadronic repulsion in the HRG phase and the perturbative QCD interactions in the QGP phase. For a first order hadron-quark matter phase transition to occur one will therefore require large fluctuations in the critical thermal parameters, which might arise due to superheating, supercooling or other nonequlibrium effects. We also discuss a scenario proposed earlier, leading to a possible strangeness separation process during hadronization.

  11. Strange and charm quark spins from the anomalous Ward identity

    NASA Astrophysics Data System (ADS)

    Gong, Ming; Yang, Yi-Bo; Liang, Jian; Alexandru, Andrei; Draper, Terrence; Liu, Keh-Fei; χQCD Collaboration

    2017-06-01

    We present a calculation of the strange and charm quark contributions to the nucleon spin from the anomalous Ward identity (AWI). This is performed with overlap valence quarks on 2 +1 -flavor domain-wall fermion gauge configurations on a 2 43×64 lattice with lattice spacing a-1=1.73 GeV and the light sea mass at mπ=330 MeV . To satisfy the AWI, the overlap fermion for the pseudoscalar density and the overlap Dirac operator for the topological density, which do not have multiplicative renormalization, are used to normalize the form factor of the local axial-vector current at finite q2. For the charm quark, we find that the negative pseudoscalar term almost cancels the positive topological term. For the strange quark, the pseudoscalar term is less negative than that of the charm. By imposing the AWI, the strange gA(q2) at q2=0 is obtained by a global fit of the pseudoscalar and the topological form factors, together with gA(q2) and the induced pseudoscalar form factor hA(q2) at finite q2. The chiral extrapolation to the physical pion mass gives Δ s +Δ s ¯=-0.0403 (44 )(78 ).

  12. Neutron stars, strange stars, and the nuclear equation of state

    SciTech Connect

    Weber, F.; Glendenning, N.K.

    1992-11-02

    This article consists of three parts. In part one we review the present status of dense nuclear matter calculations, and introduce a representative collection of realistic nuclear equations of state which are derived for different assumptions about the physical behavior of dense matter (baryon population, pion condensation,.possible transition of baryon matter to quark matter). In part two we review recently performed non-rotating and rotating compact star calculations performed for these equations of state. The minimum stable rotational periods of compact stars, whose knowledge is of decisive importance for the interpretation of rapidly rotating pulsars, axe determined. For this purpose two different limits on stable rotation are studied: rotation at the general relativistic Kepler period (below which mass shedding at the star`s equator sets in), and, secondly, rotation at the gravitational radiation-reaction instability (at which emission of gravitational waves set in which slows the star down). Part three of this article deals with the properties of hypothetical strange stars. Specifically we investigate the amount of nuclear solid crust that can be carried by a rotating strange star, and answer the question whether such objects can give rise to the observed phenomena of pulsar glitches, which is at the present time the only astrophysical test of the strange-quark-matter hypothesis.

  13. Neutron stars, strange stars, and the nuclear equation of state

    SciTech Connect

    Weber, F.; Glendenning, N.K.

    1992-11-02

    This article consists of three parts. In part one we review the present status of dense nuclear matter calculations, and introduce a representative collection of realistic nuclear equations of state which are derived for different assumptions about the physical behavior of dense matter (baryon population, pion condensation,.possible transition of baryon matter to quark matter). In part two we review recently performed non-rotating and rotating compact star calculations performed for these equations of state. The minimum stable rotational periods of compact stars, whose knowledge is of decisive importance for the interpretation of rapidly rotating pulsars, axe determined. For this purpose two different limits on stable rotation are studied: rotation at the general relativistic Kepler period (below which mass shedding at the star's equator sets in), and, secondly, rotation at the gravitational radiation-reaction instability (at which emission of gravitational waves set in which slows the star down). Part three of this article deals with the properties of hypothetical strange stars. Specifically we investigate the amount of nuclear solid crust that can be carried by a rotating strange star, and answer the question whether such objects can give rise to the observed phenomena of pulsar glitches, which is at the present time the only astrophysical test of the strange-quark-matter hypothesis.

  14. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... 2000. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of ... 2000 - The Red Sea between the East Africa coast and Saudi Arabian peninsula. project:  MISR category:  ...

  15. Make It New: The Queens Library for Teens and Dallas's Bookmarks

    ERIC Educational Resources Information Center

    O'Connor, Maureen; Kenney, Brian

    2008-01-01

    Each weekday when school let out, the Queens Library at Far Rockaway--a branch of the Queens Library in New York City--would fill with nearly 100 teens. Drawn by the public-use computers, many others, who had dropped out of school, would also crowd in. To invoke a cliche, the situation was both an opportunity and a challenge. The popularity of the…

  16. New components of the honey bee (Apis mellifera L.) queen retinue pheromone.

    PubMed

    Keeling, Christopher I; Slessor, Keith N; Higo, Heather A; Winston, Mark L

    2003-04-15

    The honey bee queen produces pheromones that function in both releaser and primer roles such as attracting a retinue of workers around her, attracting drones on mating flights, preventing workers from reproducing at the individual (worker egg-laying) and colony (swarming) level, and regulating several other aspects of colony functioning. The queen mandibular pheromone (QMP), consisting of five synergistic components, is the only pheromone chemically identified in the honey bee (Apis mellifera L.) queen, but this pheromone does not fully duplicate the pheromonal activity of a full queen extract. To identify the remaining unknown compounds for retinue attraction, honey bee colonies were selectively bred to have low response to synthetic QMP and high response to a queen extract in a laboratory retinue bioassay. Workers from these colonies were then used in the bioassay to guide the isolation and identification of the remaining active components. Four new compounds were identified from several glandular sources that account for the majority of the difference in retinue attraction between synthetic QMP and queen extract: methyl (Z)-octadec-9-enoate (methyl oleate), (E)-3-(4-hydroxy-3-methoxyphenyl)-prop-2-en-1-ol (coniferyl alcohol), hexadecan-1-ol, and (Z9,Z12,Z15)-octadeca-9,12,15-trienoic acid (linolenic acid). These compounds were inactive alone or in combination, and they only elicited attraction in the presence of QMP. There was still unidentified activity remaining in the queen extract. The queen therefore produces a synergistic, multiglandular pheromone blend of at least nine compounds for retinue attraction, the most complex pheromone blend known for inducing a single behavior in any organism.

  17. Make It New: The Queens Library for Teens and Dallas's Bookmarks

    ERIC Educational Resources Information Center

    O'Connor, Maureen; Kenney, Brian

    2008-01-01

    Each weekday when school let out, the Queens Library at Far Rockaway--a branch of the Queens Library in New York City--would fill with nearly 100 teens. Drawn by the public-use computers, many others, who had dropped out of school, would also crowd in. To invoke a cliche, the situation was both an opportunity and a challenge. The popularity of the…

  18. Colony fusion in Argentine ants is guided by worker and queen cuticular hydrocarbon profile similarity.

    PubMed

    Vásquez, Gissella M; Schal, Coby; Silverman, Jules

    2009-08-01

    Introduced populations of the Argentine ant, Linepithema humile, have experienced moderate to severe losses of genetic diversity, which may have affected nestmate recognition to various degrees. We hypothesized that cuticular hydrocarbons (CHC) serve as nestmate recognition cues, and facilitate colony fusion of unrelated L. humile colonies that share similar CHC profiles. In this study, we paired six southeastern U.S. L. humile colonies in a 6-month laboratory fusion assay, and determined if worker and queen CHC profile similarity between colonies was associated with colony fusion and intercolony genetic similarity. We also compared worker and queen CHC profiles between fused colony pairs and unpaired controls to determine if worker and queen chemical profiles changed after fusion. We found that colony fusion correlated with the CHC similarity of workers and queens, with the frequency of fusion increasing with greater CHC profile similarity between colonies. Worker and queen CHC profile similarity between colonies also was associated with genetic similarity between colonies. Queen CHC profiles in fused colonies appeared to be a mix of the two colony phenotypes. In contrast, when only one of the paired colonies survived, the CHC profile of the surviving queens did not diverge from that of the colony of origin. Similarly, workers in non-fused colonies maintained their colony-specific CHC, whereas in fused colonies the worker CHC profiles were intermediate between those of the two colonies. These results suggest a role for CHC in regulating interactions among mutually aggressive L. humile colonies, and demonstrate that colony fusion correlates with both genetic and CHC similarities. Further, changes in worker and queen chemical profiles in fused colonies suggest that CHC plasticity may sustain the cohesion of unrelated L. humile colonies that had fused.

  19. Strength in numbers: large and permanent colonies have higher queen oviposition rates in the invasive Argentine ant (Linepithema humile, Mayr).

    PubMed

    Abril, Sílvia; Gómez, Crisanto

    2014-03-01

    Polydomy associated with unicoloniality is a common trait of invasive species. In the invasive Argentine ant, colonies are seasonally polydomous. Most follow a seasonal fission-fussion pattern: they disperse in the spring and summer and aggregate in the fall and winter. However, a small proportion of colonies do not migrate; instead, they inhabit permanent nesting sites. These colonies are large and highly polydomous. The aim of this study was to (1) search for differences in the fecundity of queens between mother colonies (large and permanent) and satellite colonies (small and temporal), (2) determine if queens in mother and satellite colonies have different diets to clarify if colony size influences social organization and queen feeding, and (3) examine if colony location relative to the invasion front results in differences in the queen's diet. Our results indicate that queens from mother nests are more fertile than queens from satellite nests and that colony location does not affect queen oviposition rate. Ovarian dissections suggest that differences in ovarian morphology are not responsible for the higher queen oviposition rate in mother vs. satellite nests, since there were no differences in the number and length of ovarioles in queens from the two types of colonies. In contrast, the higher δ(15)N values of queens from mother nests imply that greater carnivorous source intake accounts for the higher oviposition rates. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Effects of non-Newtonian gravity on the properties of strange stars

    NASA Astrophysics Data System (ADS)

    Lu, Zhen-Yan; Peng, Guang-Xiong; Zhou, Kai

    2017-02-01

    The properties of strange star matter are studied in the equivparticle model with inclusion of non-Newtonian gravity. It is found that the inclusion of non-Newtonian gravity makes the equation of state stiffer if Witten’s conjecture is true. Correspondingly, the maximum mass of strange stars becomes as large as two times the solar mass, and the maximum radius also becomes bigger. The coupling to boson mass ratio has been constrained within the stability range of strange quark matter.

  1. Assessment of alteration processes on circumstellar and interstellar grains in Queen Alexandra Range 97416

    NASA Astrophysics Data System (ADS)

    Bose, Maitrayee; Zega, Thomas J.; Williams, Peter

    2014-08-01

    Insight into the presolar and interstellar grain inventory of the CO3 chondrite Queen Alexandra Range (QUE) 97416 is gained through correlated secondary ion mass spectrometry (SIMS), transmission electron microscopy (TEM), and synchrotron-based X-ray absorption near-edge structure spectroscopy (XANES). Only one presolar silicate grain [O17/O16=(9.96±0.75)×10-4; O18/O16=(19.49±0.96)×10-4] that may have formed in a low-mass Red Giant or Asymptotic Giant Branch star occurs in the coarse-grained matrix of QUE 97416. No other presolar grains were identified. Although presolar grains are rare in QUE 97416, numerous (898±259 ppm) 15N-rich domains (δN15∼+1447‰ to +3069‰) occur in the thin section. Based on TEM of an extracted section, two 15N-rich domains are amorphous, C-bearing, and texturally uniform, and they are embedded in a ferromagnesian silicate matrix with varied grain sizes. The individual 15N-rich organic regions with high δN15 (+2942±107‰ and +2341±140‰) exhibit diverse carbon functional groups, such as aromatic, vinyl-keto, amidyl, and carboxylic functionality, while the nitrogen XANES reveals traces of nitrile functionality. QUE 97416 appears to have escaped aqueous alteration based on the absence of hydrated minerals but is thermally altered, which could have resulted in the destruction of presolar grains. However, this process at >400 °C metamorphic temperatures was inefficient in destroying the carriers of N isotope anomalies, which may indicate the resistant nature of the organic carriers and/or the limited extent of thermal metamorphism on the QUE 97416 parent body.

  2. COORDINATED ANALYSES OF PRESOLAR GRAINS IN THE ALLAN HILLS 77307 AND QUEEN ELIZABETH RANGE 99177 METEORITES

    SciTech Connect

    Nguyen, Ann N.; Nittler, Larry R.; Alexander, Conel M. O'D.; Stadermann, Frank J.; Stroud, Rhonda M.

    2010-08-10

    We report the identification of presolar silicates ({approx}177 ppm), presolar oxides ({approx}11 ppm), and one presolar SiO{sub 2} grain in the Allan Hills (ALHA) 77307 chondrite. Three grains having Si-isotopic compositions similar to SiC X and Z grains were also identified, though the mineral phases are unconfirmed. Similar abundances of presolar silicates ({approx}152 ppm) and oxides ({approx}8 ppm) were also uncovered in the primitive CR chondrite Queen Elizabeth Range (QUE) 99177, along with 13 presolar SiC grains and one presolar silicon nitride. The O-isotopic compositions of the presolar silicates and oxides indicate that most of the grains condensed in low-mass red giant and asymptotic giant branch stars. Interestingly, unlike presolar oxides, few presolar silicate grains have isotopic compositions pointing to low-metallicity, low-mass stars (Group 3). The {sup 18}O-rich (Group 4) silicates, along with the few Group 3 silicates that were identified, likely have origins in supernova outflows. This is supported by their O- and Si-isotopic compositions. Elemental compositions for 74 presolar silicate grains were determined by scanning Auger spectroscopy. Most of the grains have non-stoichiometric elemental compositions inconsistent with pyroxene or olivine, the phases commonly used to fit astronomical spectra, and have comparable Mg and Fe contents. Non-equilibrium condensation and/or secondary alteration could produce the high Fe contents. Transmission electron microscopic analysis of three silicate grains also reveals non-stoichiometric compositions, attributable to non-equilibrium or multistep condensation, and very fine scale elemental heterogeneity, possibly due to subsequent annealing. The mineralogies of presolar silicates identified in meteorites thus far seem to differ from those in interplanetary dust particles.

  3. Termite queens close the sperm gates of eggs to switch from sexual to asexual reproduction.

    PubMed

    Yashiro, Toshihisa; Matsuura, Kenji

    2014-12-02

    Males and females are in conflict over genetic transmission in the evolution of parthenogenesis, because it enhances female reproductive output but deprives the males' genetic contribution. For males, any trait that coerces females into sexual reproduction should increase their fitness. However, in the termite Reticulitermes speratus, queens produce their replacements (neotenic queens) parthenogenetically while using normal sexual reproduction to produce other colony members. Here, we show that termite queens produce parthenogenetic offspring in the presence of kings by closing the micropyles (sperm gates; i.e., openings for sperm entry) of their eggs. Our field survey showed that termite eggs show large variation in numbers of micropyles, with some having none. Microsatellite analysis showed that embryos of micropyleless eggs develop parthenogenetically, whereas those of eggs with micropyles are fertilized and develop sexually. Surveys of eggs among queens of different age groups showed that queens begin to lay micropyleless eggs when they are older and thus, need to produce their replacements parthenogenetically. In addition, we found clear seasonality in new neotenic queen differentiation and micropyleless egg production. This micropyle-dependent parthenogenesis is the first identification, to our knowledge, of the mechanism through which females control egg fertilization over time in diploid animals, implying a novel route of the evolution of parthenogenesis in favor of female interests without interference from males.

  4. Glandular Epithelium as a Possible Source of a Fertility Signal in Ectatomma tuberculatum (Hymenoptera: Formicidae) Queens

    PubMed Central

    da Hora, Riviane Rodigues; Delabie, Jacques Hubert Charles; dos Santos, Carolina Gonçalves; Serrão, José Eduardo

    2010-01-01

    The wax layer covering the insect's cuticle plays an important protective role, as for example, uncontrolled water loss. In social insects, wax production is well-known in some bees that use it for nest building. Curiously, mated-fertile queens of the ant Ectatomma tuberculatum produce an uncommon extra-wax coat and, consequently queens (mated-fertile females) are matte due to such extra cuticular hydrocarbon (CHC) coat that covers the cuticle and masks the brightness of the queens' cuticle while gynes (virgin-infertile queens) are shiny. In this study, histological analysis showed differences in the epidermis between fertile (i.e., queens or gynes with highly ovarian activity) and infertile females (gynes or workers with non developed ovaries). In fertile females the epidermis is a single layer of cubic cells found in all body segments whereas in infertile females it is a thin layer of flattened cells. Ultrastructural features showed active secretory tissue from fertile females similar to the glandular epithelium of wax-producing bees (type I gland). Different hypotheses related to the functions of the glandular epithelium exclusive to the E. tuberculatum fertile queens are discussed. PMID:20419093

  5. Glandular epithelium as a possible source of a fertility signal in Ectatomma tuberculatum (Hymenoptera: Formicidae) queens.

    PubMed

    da Hora, Riviane Rodigues; Delabie, Jacques Hubert Charles; dos Santos, Carolina Gonçalves; Serrão, José Eduardo

    2010-04-19

    The wax layer covering the insect's cuticle plays an important protective role, as for example, uncontrolled water loss. In social insects, wax production is well-known in some bees that use it for nest building. Curiously, mated-fertile queens of the ant Ectatomma tuberculatum produce an uncommon extra-wax coat and, consequently queens (mated-fertile females) are matte due to such extra cuticular hydrocarbon (CHC) coat that covers the cuticle and masks the brightness of the queens' cuticle while gynes (virgin-infertile queens) are shiny. In this study, histological analysis showed differences in the epidermis between fertile (i.e., queens or gynes with highly ovarian activity) and infertile females (gynes or workers with non developed ovaries). In fertile females the epidermis is a single layer of cubic cells found in all body segments whereas in infertile females it is a thin layer of flattened cells. Ultrastructural features showed active secretory tissue from fertile females similar to the glandular epithelium of wax-producing bees (type I gland). Different hypotheses related to the functions of the glandular epithelium exclusive to the E. tuberculatum fertile queens are discussed.

  6. Gender-bias primes elicit queen-bee responses among senior policewomen.

    PubMed

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

    2011-10-01

    Queen bees are senior women in male-dominated organizations who have achieved success by emphasizing how they differ from other women. Although the behavior of queen bees tends to be seen as contributing to gender disparities in career outcomes, we argue that queen-bee behavior is actually a result of the gender bias and social identity threat that produce gender disparities in career outcomes. In the experiment reported here, we asked separate groups of senior policewomen to recall the presence or absence of gender bias during their careers, and we measured queen-bee responses (i.e., masculine self-descriptions, in-group distancing, and denying of discrimination). Such gender-bias priming increased queen-bee responses among policewomen with low gender identification, but policewomen with high gender identification responded with increased motivation to improve opportunities for other women. These results suggest that gender-biased work environments shape women's behavior by stimulating women with low gender identification to dissociate with other women and to display queen-bee responses as a way to achieve individual mobility.

  7. Facultative use of thelytokous parthenogenesis for queen production in the polyandrous ant Cataglyphis cursor.

    PubMed

    Doums, C; Cronin, A L; Ruel, C; Fédérici, P; Haussy, C; Tirard, C; Monnin, T

    2013-07-01

    The evolutionary paradox of sex remains one of the major debates in evolutionary biology. The study of species capable of both sexual and asexual reproduction can elucidate factors important in the evolution of sex. One such species is the ant Cataglyphis cursor, where the queen maximizes the transmission of her genes by producing new queens (gynes) asexually while simultaneously maintaining a genetically diverse workforce via the sexual production of workers. We show that the queen can also produce gynes sexually and may do so to offset the costs of asexual reproduction. We genotyped 235 gynes from 18 colonies and found that half were sexually produced. A few colonies contained both sexually and asexually produced gynes. Although workers in this species can also use thelytoky, we found no evidence of worker production of gynes based on genotypes of 471 workers from the six colonies producing sexual gynes. Gynes are thus mainly, and potentially exclusively, produced by the queen. Simulations of gynes inbreeding level following one to ten generations of automictic thelytoky suggest that the queen switches between or combines thelytoky and sex, which may reduce the costs of inbreeding. This is supported by the relatively small size of inbred gynes in one colony, although we found no relationship between the level of inbreeding and immune parameters. Such facultative use of sex and thelytoky by individual queens contrasts with other known forms of parthenogenesis in ants, which are typically characterized by distinct lineages specializing in one strategy or the other.

  8. Intragenomic conflict over queen determination favours genomic imprinting in eusocial Hymenoptera

    PubMed Central

    Dobata, Shigeto; Tsuji, Kazuki

    2012-01-01

    Colonies of eusocial Hymenoptera, such as ants, bees and wasps, have long been recognized as candidates for the study of genomic imprinting on the grounds of evolutionary conflicts that arise from close interactions among colony members and relatedness asymmetry owing to haplodiploidy. Although a general kinship theory of genomic imprinting predicts its occurrence under various circumstances of the colony life cycle, new theoretical approaches are required to account for the specifics of real colonies based on recent advances in molecular-level understanding of ants and honeybees. Using a multivariate quantitative genetic model, we examined the potential impact of genomic imprinting on genes that determine the carrier female's propensity to develop into the queen caste. When queen overproduction owing to the increased propensity comes at a colony-level cost, the conflict between maternally and paternally inherited genes in polyandrous (queen multiple mating) colonies favours genomic imprinting. Moreover, we show that the genomic imprinting can occur even under monandry (queen single mating), once incorporating the costs differentially experienced by new males and new queens. Our model predicts the existence of imprinted ‘genetic royal cheats’ with patriline-specific expression in polyandrous colonies, and seems consistent with the paternal effect on queen determination in monandrous Argentine ants. PMID:22378809

  9. Intragenomic conflict over queen determination favours genomic imprinting in eusocial Hymenoptera.

    PubMed

    Dobata, Shigeto; Tsuji, Kazuki

    2012-07-07

    Colonies of eusocial Hymenoptera, such as ants, bees and wasps, have long been recognized as candidates for the study of genomic imprinting on the grounds of evolutionary conflicts that arise from close interactions among colony members and relatedness asymmetry owing to haplodiploidy. Although a general kinship theory of genomic imprinting predicts its occurrence under various circumstances of the colony life cycle, new theoretical approaches are required to account for the specifics of real colonies based on recent advances in molecular-level understanding of ants and honeybees. Using a multivariate quantitative genetic model, we examined the potential impact of genomic imprinting on genes that determine the carrier female's propensity to develop into the queen caste. When queen overproduction owing to the increased propensity comes at a colony-level cost, the conflict between maternally and paternally inherited genes in polyandrous (queen multiple mating) colonies favours genomic imprinting. Moreover, we show that the genomic imprinting can occur even under monandry (queen single mating), once incorporating the costs differentially experienced by new males and new queens. Our model predicts the existence of imprinted 'genetic royal cheats' with patriline-specific expression in polyandrous colonies, and seems consistent with the paternal effect on queen determination in monandrous Argentine ants.

  10. Strange quark matter and quark stars with the Dyson-Schwinger quark model

    NASA Astrophysics Data System (ADS)

    Chen, H.; Wei, J.-B.; Schulze, H.-J.

    2016-09-01

    We calculate the equation of state of strange quark matter and the interior structure of strange quark stars in a Dyson-Schwinger quark model within rainbow or Ball-Chiu vertex approximation. We emphasize constraints on the parameter space of the model due to stability conditions of ordinary nuclear matter. Respecting these constraints, we find that the maximum mass of strange quark stars is about 1.9 solar masses, and typical radii are 9-11km. We obtain an energy release as large as 3.6 × 10^{53} erg from conversion of neutron stars into strange quark stars.

  11. Colony Failure Linked to Low Sperm Viability in Honey Bee (Apis mellifera) Queens and an Exploration of Potential Causative Factors

    PubMed Central

    Pettis, Jeffery S.; Rice, Nathan; Joselow, Katie; vanEngelsdorp, Dennis; Chaimanee, Veeranan

    2016-01-01

    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 months when historically a queen might live one to two years. This high rate of queen failure coincides with the high mortality rates of colonies in the US, some years with >50% of colonies dying. In the current study, surveys of sperm viability in US queens were made to determine if sperm viability plays a role in queen or colony failure. Wide variation was observed in sperm viability from four sets of queens removed from colonies that beekeepers rated as in good health (n = 12; average viability = 92%), were replacing as part of normal management (n = 28; 57%), or where rated as failing (n = 18 and 19; 54% and 55%). Two additional paired set of queens showed a statistically significant difference in viability between colonies rated by the beekeeper as failing or in good health from the same apiaries. Queens removed from colonies rated in good health averaged high viability (ca. 85%) while those rated as failing or in poor health had significantly lower viability (ca. 50%). Thus low sperm viability was indicative of, or linked to, colony performance. To explore the source of low sperm viability, six commercial queen breeders were surveyed and wide variation in viability (range 60–90%) was documented between breeders. This variability could originate from the drones the queens mate with or temperature extremes that queens are exposed to during shipment. The role of shipping temperature as a possible explanation for low sperm viability was explored. We documented that during shipment queens are exposed to temperature spikes (<8 and > 40°C) and these spikes can kill 50% or more of the sperm stored in queen spermathecae in live queens. Clearly low sperm viability is

  12. Colony Failure Linked to Low Sperm Viability in Honey Bee (Apis mellifera) Queens and an Exploration of Potential Causative Factors.

    PubMed

    Pettis, Jeffery S; Rice, Nathan; Joselow, Katie; vanEngelsdorp, Dennis; Chaimanee, Veeranan

    2016-01-01

    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 months when historically a queen might live one to two years. This high rate of queen failure coincides with the high mortality rates of colonies in the US, some years with >50% of colonies dying. In the current study, surveys of sperm viability in US queens were made to determine if sperm viability plays a role in queen or colony failure. Wide variation was observed in sperm viability from four sets of queens removed from colonies that beekeepers rated as in good health (n = 12; average viability = 92%), were replacing as part of normal management (n = 28; 57%), or where rated as failing (n = 18 and 19; 54% and 55%). Two additional paired set of queens showed a statistically significant difference in viability between colonies rated by the beekeeper as failing or in good health from the same apiaries. Queens removed from colonies rated in good health averaged high viability (ca. 85%) while those rated as failing or in poor health had significantly lower viability (ca. 50%). Thus low sperm viability was indicative of, or linked to, colony performance. To explore the source of low sperm viability, six commercial queen breeders were surveyed and wide variation in viability (range 60-90%) was documented between breeders. This variability could originate from the drones the queens mate with or temperature extremes that queens are exposed to during shipment. The role of shipping temperature as a possible explanation for low sperm viability was explored. We documented that during shipment queens are exposed to temperature spikes (<8 and > 40°C) and these spikes can kill 50% or more of the sperm stored in queen spermathecae in live queens. Clearly low sperm viability is linked

  13. "Bad law" argument in Morgentaler v. The Queen.

    PubMed

    Goldberg, E M

    The issues raised by the Crown on appeal in Morgentaler v. The Queen from the acquittal of the accused were rendered moot when the Supreme Court of Canada declared the abortion statute (section 251 of the Criminal Code) to be unconstitutional. There was no need for the Court to discuss either the issue of the use of the "defence of necessity" or defence counsel's "bad law" argument. Nevertheless, Chief Justice Dickson found the "bad law" argument of defence counsel, Morris Manning, Q.C., "so troubling," he felt "compelled to comment" on it. Mr. Manning argued that, although the jury was to take its instructions in the law from the judge, it had a right not to apply the law in the case to the facts because the abortion statute was "bad law." In his decision, Chief Justice Dickson reiterated that it is the duty of the judge to instruct the jury in the law and the function of the jury to apply the facts to the law, and that Mr. Manning was wrong to tell the jury otherwise. Among other things, the Chief Justice used a "racist jury" example to demonstrate Mr. Manning's error. The author argues in this comment that the Chief Justice's example was ill-conceived and inapposite, and concludes that the jury and Mr. Manning should be commended for helping to rid Canada of an oppressive abortion law.

  14. Oxidative Stress and Anti-Oxidant Enzyme Activities in the Trophocytes and Fat Cells of Queen Honeybees (Apis mellifera)

    PubMed Central

    Hsieh, Yu-Shan

    2013-01-01

    Abstract Trophocytes and fat cells of queen honeybees have been used for delayed cellular senescence studies, but their oxidative stress and anti-oxidant enzyme activities with advancing age are unknown. In this study, we assayed reactive oxygen species (ROS) and anti-oxidant enzymes in the trophocytes and fat cells of young and old queens. Young queens had lower ROS levels, lower superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, and higher thioredoxin reductase (TR) activity compared to old queens. These results show that oxidative stress and anti-oxidant enzyme activities in trophocytes and fat cells increase with advancing age in queens and suggest that an increase in oxidative stress and a consequent increase in stress defense mechanisms are associated with the longevity of queen honeybees. PMID:23738955

  15. Discriminating strange star mergers from neutron star mergers by gravitational-wave measurements

    SciTech Connect

    Bauswein, A.; Oechslin, R.; Janka, H.-T.

    2010-01-15

    We perform three-dimensional relativistic hydrodynamical simulations of the coalescence of strange stars and explore the possibility to decide on the strange matter hypothesis by means of gravitational-wave measurements. Self-binding of strange quark matter and the generally more compact stars yield features that clearly distinguish strange star from neutron star mergers, e.g. hampering tidal disruption during the plunge of quark stars. Furthermore, instead of forming dilute halo structures around the remnant as in the case of neutron star mergers, the coalescence of strange stars results in a differentially rotating hypermassive object with a sharp surface layer surrounded by a geometrically thin, clumpy high-density strange quark matter disk. We also investigate the importance of including nonzero temperature equations of state in neutron star and strange star merger simulations. In both cases we find a crucial sensitivity of the dynamics and outcome of the coalescence to thermal effects, e.g. the outer remnant structure and the delay time of the dense remnant core to black hole collapse depend on the inclusion of nonzero temperature effects. For comparing and classifying the gravitational-wave signals, we use a number of characteristic quantities like the maximum frequency during inspiral or the dominant frequency of oscillations of the postmerger remnant. In general, these frequencies are higher for strange star mergers. Only for particular choices of the equation of state the frequencies of neutron star and strange star mergers are similar. In such cases additional features of the gravitational-wave luminosity spectrum like the ratio of energy emitted during the inspiral phase to the energy radiated away in the postmerger stage may help to discriminate coalescence events of the different types. If such characteristic quantities could be extracted from gravitational-wave signals, for instance with the upcoming gravitational-wave detectors, a decision on the

  16. Impact of queen infection on kitten susceptibility to different strains of Bartonella henselae.

    PubMed

    Fleischman, Drew A; Chomel, Bruno B; Burgos, Katlin; Kasten, Rickie W; Stuckey, Matthew J; Durden, Monica R; Mirrashed, Hannah; Diniz, Pedro Paulo V P

    2015-11-18

    Domestic cats are the natural reservoir of Bartonella henselae, the agent of cat scratch disease in humans. In kittens, maternal IgG antibodies are detectable within two weeks postpartum, weaning in six to ten weeks postpartum and kittens as young as six to eight weeks old can become bacteremic in a natural environment. The study's objective was to evaluate if maternal antibodies against a specific B. henselae strain protect kittens from infection with the same strain or a different strain from the same genotype. Three seronegative and Bartonella-free pregnant queens were infected with the same strain of B. henselae genotype II during pregnancy. Kittens from queens #1 and #2 were challenged with the same strain used to infect the queens while kittens from queen #3 were challenged with a different genotype II strain. All queens gave birth to non-bacteremic kittens. After challenge, all kittens from queens infected with the same strain seroconverted, with six out of the seven kittens presenting no to very low levels of transitory bacteremia. Conversely, all four kittens challenged with a different strain developed high bacteremia (average 47,900 CFU/mL by blood culture and 146,893 bacteria/mL by quantitative PCR). Overall, qPCR and bacterial culture were in good agreement for all kittens (Kappa Cohen's agreement of 0.78). This study demonstrated that young kittens can easily be infected with a different strain of B. henselae at a very young age, even in the presence of maternal antibodies, underlining the importance of flea control in pregnant queens and young kittens. Copyright © 2015. Published by Elsevier B.V.

  17. Transcriptomic Signatures Mirror the Lack of the Fecundity/Longevity Trade-Off in Ant Queens

    PubMed Central

    von Wyschetzki, Katharina; Rueppell, Olav; Oettler, Jan; Heinze, Jürgen

    2015-01-01

    Life-history theory predicts a trade-off between reproductive investment and self-maintenance. The negative association between fertility and longevity found throughout multicellular organisms supports this prediction. As an important exception, the reproductives of many eusocial insects (ants, bees, and termites) are simultaneously very long-lived and highly fertile. Here, we examine the proximate basis for this exceptional relationship by comparing whole-body transcriptomes of differently aged queens of the ant Cardiocondyla obscurior. We show that the sets of genes differentially expressed with age significantly overlap with age-related expression changes previously found in female Drosophila melanogaster. We identified several developmental processes, such as the generation of neurons, as common signatures of aging. More generally, however, gene expression in ant queens and flies changes with age mainly in opposite directions. In contrast to flies, reproduction-associated genes were upregulated and genes associated with metabolic processes and muscle contraction were downregulated in old relative to young ant queens. Furthermore, we searched for putative C. obscurior longevity candidates associated with the previously reported lifespan-prolonging effect of mating by comparing the transcriptomes of queens that differed in mating and reproductive status. We found 21 genes, including the putative aging candidate NLaz (an insect homolog of APOD), which were consistently more highly expressed in short-lived, unmated queens than in long-lived, mated queens. Our study provides clear evidence that the alternative regulation of conserved molecular pathways that mediate the interplay among mating, egg laying, and aging underlies the lack of the fecundity/longevity trade-off in ant queens. PMID:26341296

  18. 78 FR 34310 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Queen Conch Fishery of Puerto...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ...NMFS proposes regulations to implement Regulatory Amendment 2 to the Fishery Management Plan (FMP) for the Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands (USVI) (Regulatory Amendment 2), as prepared by the Caribbean Fishery Management Council (Council). If implemented, this rule would revise the commercial trip limit for queen conch in the Caribbean exclusive economic zone (EEZ) to be compatible with the trip limit in USVI territorial waters. The purpose of this proposed rule is to improve the compatibility of Federal and USVI territorial regulations for queen conch in order to facilitate enforcement efforts while ensuring the long-term health of the queen conch resource.

  19. The effect of queen pheromone status on Varroa mite removal from honey bee colonies with different grooming ability.

    PubMed

    Bahreini, Rassol; Currie, Robert W

    2015-07-01

    The objective of this study was to assess the effects of honey bees (Apis mellifera L.) with different grooming ability and queen pheromone status on mortality rates of Varroa mites (Varroa destructor Anderson and Trueman), mite damage, and mortality rates of honey bees. Twenty-four small queenless colonies containing either stock selected for high rates of mite removal (n = 12) or unselected stock (n = 12) were maintained under constant darkness at 5 °C. Colonies were randomly assigned to be treated with one of three queen pheromone status treatments: (1) caged, mated queen, (2) a synthetic queen mandibular pheromone lure (QMP), or (3) queenless with no queen substitute. The results showed overall mite mortality rate was greater in stock selected for grooming than in unselected stock. There was a short term transitory increase in bee mortality rates in selected stock when compared to unselected stock. The presence of queen pheromone from either caged, mated queens or QMP enhanced mite removal from clusters of bees relative to queenless colonies over short periods of time and increased the variation in mite mortality over time relative to colonies without queen pheromone, but did not affect the proportion of damaged mites. The effects of source of bees on mite damage varied with time but damage to mites was not reliably related to mite mortality. In conclusion, this study showed differential mite removal of different stocks was possible under low temperature. Queen status should be considered when designing experiments using bioassays for grooming response.

  20. Effect of a fungicide and spray adjuvant on queen-rearing success in honey bees (Hymenoptera: Apidae).

    PubMed

    Johnson, Reed M; Percel, Eric G

    2013-10-01

    Commercial producers of honey bee queens (Apis mellifera L.) have reported unexplained loss of immature queens during the larval or pupal stage. Many affected queen-rearing operations are situated among the almond orchards of California and report these losses in weeks after almond trees bloom. Almond flowers are a rich foraging resource for bees, but are often treated with fungicides, insecticides, and spray adjuvants during bloom. Anecdotal reports by queen producers associate problems in queen development with application of the fungicide Pristine (boscalid and pyraclostrobin) and spray adjuvants that are tank-mixed with it. To test the effect of these compounds on queen development, a new bioassay was developed in which queens are reared in closed swarm boxes for 4 d, until capping, with nurse bees fed exclusively on artificially contaminated pollen. Pollen was treated with four concentrations of formulated Pristine (0.4, 4, 40, and 400 ppm), a spray adjuvant (Break-Thru, 200 ppm), the combination of Pristine and spray adjuvant (400:200 ppm), the insect growth regulator insecticide diflubenzuron (100 ppm) as a positive control, or water as negative control. Chemical analysis revealed that low concentrations of pyraclostrobin (50 ppb), but no boscalid, were detectable in royal jelly secreted by nurse bees feeding on treated pollen. No significant difference in queen development or survival was observed between any of the experimental treatments and the negative control. Only diflubenzuron, the positive control, caused a substantial reduction in survival of immature queens.

  1. A distinct role of the queen in coordinated workload and soil distribution in eusocial naked mole-rats.

    PubMed

    Kutsukake, Nobuyuki; Inada, Masayuki; Sakamoto, Shinsuke H; Okanoya, Kazuo

    2012-01-01

    We investigated how group members achieve collective decision-making, by considering individual intrinsic behavioural rules and behavioural mechanisms for maintaining social integration. Using a simulated burrow environment, we investigated the behavioural rules of coordinated workload for soil distribution in a eusocial mammal, the naked mole-rat (Heterocephalus glaber). We tested two predictions regarding a distinct role of the queen, a socially dominant individual in the caste system: the presence of a queen would increase the workload of other caste individuals, and the cues by a queen would affect the soil distribution. In experiment 1, we placed four individuals of various castes from the same colony into an experimental burrow. Workers exhibited the highest frequency of workload compared to other castes. The presence of a queen activated the workload by other individuals. Individuals showed a consistent workload in a particular direction so as to bias the soil distribution. These results suggest that individuals have a consensus on soil distribution and that the queen plays a distinct role. In experiment 2, we placed the odour of a queen in one of four cells and observed its effect on other individuals' workload and soil distribution. Relative to other cells, individuals frequently dug in the queen cell so the amount of soil in the queen cell decreased. These results suggest that queen odour is an important cue in coordinated workload and soil distribution in this species.

  2. A Distinct Role of the Queen in Coordinated Workload and Soil Distribution in Eusocial Naked Mole-Rats

    PubMed Central

    Kutsukake, Nobuyuki; Inada, Masayuki; Sakamoto, Shinsuke H.; Okanoya, Kazuo

    2012-01-01

    We investigated how group members achieve collective decision-making, by considering individual intrinsic behavioural rules and behavioural mechanisms for maintaining social integration. Using a simulated burrow environment, we investigated the behavioural rules of coordinated workload for soil distribution in a eusocial mammal, the naked mole-rat (Heterocephalus glaber). We tested two predictions regarding a distinct role of the queen, a socially dominant individual in the caste system: the presence of a queen would increase the workload of other caste individuals, and the cues by a queen would affect the soil distribution. In experiment 1, we placed four individuals of various castes from the same colony into an experimental burrow. Workers exhibited the highest frequency of workload compared to other castes. The presence of a queen activated the workload by other individuals. Individuals showed a consistent workload in a particular direction so as to bias the soil distribution. These results suggest that individuals have a consensus on soil distribution and that the queen plays a distinct role. In experiment 2, we placed the odour of a queen in one of four cells and observed its effect on other individuals’ workload and soil distribution. Relative to other cells, individuals frequently dug in the queen cell so the amount of soil in the queen cell decreased. These results suggest that queen odour is an important cue in coordinated workload and soil distribution in this species. PMID:22957085

  3. Enhanced production of multi-strange hadrons in high-multiplicity proton-proton collisions

    NASA Astrophysics Data System (ADS)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Rinella, G. Aglieri; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Molina, R. Alfaro; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Prado, C. Alves Garcia; An, M.; Andrei, C.; Andrews, H. A.; Andronic, A.; Anguelov, V.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Balasubramanian, S.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Camejo, A. Batista; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Martinez, H. Bello; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Cai, X.; Caines, H.; Diaz, L. Calero; Caliva, A.; Villar, E. Calvo; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castellanos, J. Castillo; Castro, A. J.; Casula, E. A. R.; Sanchez, C. Ceballos; Cepila, J.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Barroso, V. Chibante; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Balbastre, G. Conesa; Del Valle, Z. Conesa; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Morales, Y. Corrales; Maldonado, I. Cortés; Cortese, P.; Cosentino, M. R.; Costa, F.; Crkovska, J.; Crochet, P.; Albino, R. Cruz; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; de, S.; de Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; De Marco, N.; de Pasquale, S.; de Souza, R. D.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; di Bari, D.; di Mauro, A.; di Nezza, P.; di Ruzza, B.; Corchero, M. A. Diaz; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Gimenez, D. Domenicis; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Téllez, A. Fernández; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Girard, M. Fusco; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Garg, K.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Coral, D. M. Goméz; Ramirez, A. Gomez; Gonzalez, A. S.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosse-Oetringhaus, J. F.; Grosso, R.; Gruber, L.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Corral, G. Herrera; Herrmann, F.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Horak, D.; Hosokawa, R.; Hristov, P.; Hughes, C.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Incani, E.; Ippolitov, M.; Irfan, M.; Isakov, V.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacak, B.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Bustamante, R. T. Jimenez; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Kar, S.; Uysal, A. Karasu; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Khan, M. Mohisin; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Khatun, A.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.; Kim, H.; Kim, J. S.; Kim, J.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Meethaleveedu, G. Koyithatta; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; de Guevara, P. Ladron; Fernandes, C. Lagana; Lakomov, I.; Langoy, R.; Lapidus, K.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, S.; Lehas, F.; Lehner, S.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; Monzón, I. León; Vargas, H. León; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Lopez, X.; Torres, E. López; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Lupi, M.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Cervantes, I. Maldonado; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; García, G. Martínez; Pedreira, M. Martinez; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzilli, M.; Mazzoni, M. A.; McDonald, D.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Pérez, J. Mercado; Meres, M.; Mhlanga, S.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Mishra, T.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Zetina, L. Montaño; Montes, E.; de Godoy, D. A. Moreira; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Münning, K.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; da Luz, H. Natal; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; de Oliveira, R. A. Negrao; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Oleniacz, J.; da Silva, A. C. Oliveira; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Oravec, M.; Velasquez, A. Ortiz; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, D.; Pagano, P.; Paić, G.; Pal, S. K.; Palni, P.; Pan, J.; Pandey, A. K.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Peng, X.; da Costa, H. Pereira; Peresunko, D.; Lezama, E. Perez; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Poppenborg, H.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Ravasenga, I.; Read, K. F.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Cahuantzi, M. Rodríguez; Manso, A. Rodriguez; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Montero, A. J. Rubio; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Saarinen, S.; Sadhu, S.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sano, M.; Sarkar, D.; Sarkar, N.; Sarma, P.; Scapparone, E.; Scarlassara, F.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schmidt, M.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Sheikh, A. I.; Shigaki, K.; Shou, Q.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singhal, V.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Sozzi, F.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Stachel, J.; Stan, I.; Stankus, P.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Sumowidagdo, S.; Swain, S.; Szabo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Muñoz, G. Tejeda; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thakur, D.; Thomas, D.; Tieulent, R.; Tikhonov, A.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vala, M.; Palomo, L. Valencia; van der Maarel, J.; van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vyvre, P. Vande; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Doce, O. Vázquez; Vechernin, V.; Veen, A. M.; Velure, A.; Vercellin, E.; Limón, S. Vergara; Vernet, R.; Vickovic, L.; Viinikainen, J.; Vilakazi, Z.; Baillie, O. Villalobos; Tello, A. Villatoro; Vinogradov, A.; Vinogradov, L.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilk, G.; Wilkinson, J.; Willems, G. A.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yalcin, S.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yoon, J. H.; Yurchenko, V.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

    2017-06-01

    At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark-gluon plasma (QGP). Such an exotic state of strongly interacting quantum chromodynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production of strange hadrons is observed. Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions, is more pronounced for multi-strange baryons. Several effects typical of heavy-ion phenomenology have been observed in high-multiplicity proton-proton (pp) collisions, but the enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity proton-proton collisions. We find that the integrated yields of strange and multi-strange particles, relative to pions, increases significantly with the event charged-particle multiplicity. The measurements are in remarkable agreement with the p-Pb collision results, indicating that the phenomenon is related to the final system created in the collision. In high-multiplicity events strangeness production reaches values similar to those observed in Pb-Pb collisions, where a QGP is formed.

  4. Asymmetries between strange and antistrange particle production inpion-proton interactions

    SciTech Connect

    Gutierrez, T.D.; Vogt, R.

    2002-01-29

    Recent measurements of the asymmetries between Feynman x-distributions of strange and antistrange hadrons in {pi}{sup -}A interactions show a strong effect as a function of x{sub F}. We calculate strange hadron production in the context of the intrinsic model and make predictions for particle/antiparticle asymmetries in these interactions.

  5. Aspects of strangeness production with 15 -- 30 GeV proton beams

    SciTech Connect

    Dover, C.B.

    1992-04-01

    We discuss the spectrum of physics questions related to strangeness which could be addressed with a 15--30 GeV proton storage ring. We focus on various aspects of strangeness production, including hyperon production in pp collisions, studies of hyperon-nucleon scattering, production of hyper-fragments in p-nucleus collisions, and hyperon spin observables in inclusive production.

  6. In Medium Properties of Charmed Strange Mesons in Dense Hadron ic Matter

    NASA Astrophysics Data System (ADS)

    Kumar, Sushil

    2015-05-01

    The medium modifications of the charmed strange mesons in the dense hadronic matter are investigated within chiral S U(4) model. The charmed strange meson properties modifies due to their interactions with the nucleons, hyperons and the scalar mesons (scalar-isoscalar mesons ( σ, ζ), scalar isovector meson ( δ)) in the dense hadronic medium. The various parameters used in the chiral model are obtained by fitting the vacuum baryon masses and saturation properties of nuclear matter. The non-linear coupled equations of the scalar fields are solved to obtain their baryon density, isospin and strangeness dependent values. Furthermore, the dispersion relations are derived for charmed strange mesons. Effects of isospin asymmetry and strangeness on the energies of charmed strange mesons are investigated. The in medium properties of charmed strange mesons can be particularly relevant to the experiments with neutron rich beams at the Facility for Antiproton and Ion Research (FAIR) at GSI, Germany, as well as to experiments at the Rare Isotope Accelerator (RIA) laboratory, USA. The present study of the in medium properties of charmed strange mesons will be of direct relevance for the observables from the compressed baryonic matter, resulting from the heavy ion collision experiments.

  7. Repeating Earthquakes on the Queen Charlotte Plate Boundary

    NASA Astrophysics Data System (ADS)

    Hayward, T. W.; Bostock, M. G.

    2015-12-01

    The Queen Charlotte Fault (QCF) is a major plate boundary located off the northwest coast of North America that has produced large earthquakes in 1949 (M8.1) and more recently in October, 2012 (M7.8). The 2012 event was dominated by thrusting despite the fact that plate motions at the boundary are nearly transcurrent. It is now widely believed that the plate boundary comprises the QCF (i.e., a dextral strike-slip fault) as well as an element of subduction of the Pacific Plate beneath the North American Plate. Repeating earthquakes and seismic tremor have been observed in the vicinity of the QCF; providing insight into the spatial and temporal characteristics of repeating earthquakes is the goal of this research. Due to poor station coverage and data quality, traditional methods of locating earthquakes are not applicable to these events. Instead, we have implemented an algorithm to locate local (i.e., < 100 km distance to epicenter) earthquakes using a single, three-component seismogram. This algorithm relies on the P-wave polarization and, through comparison with larger local events in the Geological Survey of Canada catalogue, is shown to yield epicentral locations accurate to within 5-10 km. A total of 24 unique families of repeating earthquakes has been identified, and 4 of these families have been located with high confidence. Their epicenters locate directly on the trace of the QCF and their depths are shallow (i.e., 5-15 km), consistent with the proposed depth of the QCF. Analysis of temporal recurrence leading up to the 2012 M7.8 event reveals a non-random pattern, with an approximately 15 day periodicity. Further analysis is planned to study whether this behaviour persists after the 2012 event and to gain insight into the effects of the 2012 event on the stress field and frictional properties of the plate boundary.

  8. Organic maturation and thermal history of Queen Charlotte Islands

    SciTech Connect

    Bustin, R.M.; Vellutini, D. )

    1989-09-01

    The level of organic maturation and thermal history of Mesozoic and Tertiary strata of the Queen Charlotte Islands have been determined with vitrinite reflectance (R{sub 0}), numerical modeling (modified Arrhenius model), and Rock-Eval Pyrolysis. The level of organic maturation increases from northern Graham to southern Moresby Island, which primarily reflects high heat flow resulting from Middle to Late Jurassic and Eocene to Oligocene plutonism and cospatial dyking. Upper Triassic-Lower Jurassic and most Cretaceous strata are overmature on Moresby Island, with R{sub 0} values ranging from 2.40 to 5.80%. Jurassic, Cretaceous, and Tertiary strata are immature to overmature on Graham Island, with R{sub 0} values ranging from 0.15% (Skonun Formation) to 2.4% (Haida Formation). Locally, R{sub 0} values up to 3.2% on Graham Island and 8.3% on Moresby Island occur adjacent to igneous intrusives. Modeling measured levels of organic maturation suggests that elevated geothermal gradients ranging from 83{degree} to 150{degree}C/km existed during Yakoun (183-178 Ma) and Masset (35-10 Ma) volcanism on Graham Island. Numerical modeling further suggests that Triassic strata on Fredrick Island and Kennecott Point (Graham Island) entered the oil window during the early Miocene, whereas Jurassic strata at Rennell Junction and Cumshewa Inlet entered the oil window during the Bajocian. Cretaceous strata on north and south Graham Island entered the oil window during the early Miocene and are currently within the oil window. The Tertiary Skonun Formation is generally immature except for strata on west and northeast Graham Island, which entered the oil window in the late Miocene.

  9. Weak production of strange particles off the nucleon

    SciTech Connect

    Alam, M. Rafi; Athar, M. Sajjad; Simo, I. Ruiz; Alvarez-Ruso, L.; Vacas, M. J. Vicente

    2015-05-15

    The strange particle production off the nucleon induced by neutrinos and antineutrinos is investigated at low and intermediate energies. We develop a microscopic model based on the SU(3) chiral Lagrangian. The studied mechanisms are the main source of single kaon production for (anti)neutrino energies up to 1.5 GeV. Using this model we have also studied the associated production of kaons and hyperons. The cross sections are large enough to be measured by experiments such as MINERνA, T2K and NOνA.

  10. Universal strangeness production in hadronic and nuclear collisions

    NASA Astrophysics Data System (ADS)

    Castorina, P.; Plumari, S.; Satz, H.

    2016-07-01

    We show that strangeness suppression in hadronic and nuclear collisions is fully determined by the initial energy density of the collision. The suppression factor γs(s), with s denoting the collision energy, can be expressed as a universal function of the initial energy density ɛ0(s), and the resulting pattern is in excellent agreement with data from p-p, p-Pb, Cu-Cu, Au-Au and Pb-Pb data over a wide range of energies and for different centralities.

  11. Properties of excited charm and charm-strange mesons

    NASA Astrophysics Data System (ADS)

    Godfrey, Stephen; Moats, Kenneth

    2016-02-01

    We calculate the properties of excited charm and charm-strange mesons. We use the relativized quark model to calculate their masses and wave functions that are used to calculate radiative transition partial widths and the 3P0 quark-pair-creation model to calculate their strong decay widths. We use these results to make quark model spectroscopic assignments for recently observed charm and charm-strange mesons. In particular, we find that the properties of the DJ(2550 )0 and DJ*(2600 )0 are consistent with those of the 2 1S0 (c u ¯) and the 2 3S1 (c u ¯) states respectively, and the D1*(2760 )0, D3*(2760 )-,and DJ(2750 )0with those of the 1 3D1 (c u ¯), 1 3D3 (d c ¯), and 1 D2(c u ¯) states respectively. We tentatively identify the DJ*(3000 )0 as the 1 3F4 (c u ¯ ) and favor the DJ(3000 )0 to be the 3 1S0 (c u ¯ ) although we do not rule out the 1 F3 and 1 F3' assignment. For the recently observed charm-strange mesons we identify the Ds1 *(2709 )±,Ds1 *(2860 )-,andDs3 *(2860 )-as the 2 3S1 (c s ¯), 1 3D1 (s c ¯), and 1 3D3 (s c ¯) states respectively and suggest that the Ds J(3044 )± is most likely the Ds 1(2 P1' ) or Ds 1(2 P1) state although it might be the Ds2 *(2 3P2 ) with the D K final state too small to be observed with current statistics. Based on the predicted properties of excited states, that they do not have too large a total width and that they have a reasonable branching ratio to simple final states, we suggest states that should be able to be found in the near future. We expect that the tables of properties summarizing our results will be useful for interpreting future observations of charm and charm-strange mesons.

  12. Strangeness suppression of qq creation observed in exclusive reactions.

    PubMed

    Mestayer, M D; Park, K; Adhikari, K P; Aghasyan, M; Pereira, S Anefalos; Ball, J; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A S; Boiarinov, S; Briscoe, W J; Brooks, W K; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; Deur, A; Djalali, C; Doughty, D; Dupre, R; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fleming, J A; Forest, T A; Garillon, B; Garçon, M; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Hakobyan, H; Hanretty, C; Hattawy, M; Holtrop, M; Hughes, S M; Hyde, C E; Ilieva, Y; Ireland, D G; Jiang, H; Jo, H S; Joo, K; Keller, D; Khandaker, M; Kim, A; Kim, W; Koirala, S; Kubarovsky, V; Kuleshov, S V; Lenisa, P; Levine, W I; Livingston, K; Lu, H Y; MacGregor, I J D; Mayer, M; McKinnon, B; Meyer, C A; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Paremuzyan, R; Peng, P; Phelps, W; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Protopopescu, D; Puckett, A J R; Raue, B A; Rimal, D; Ripani, M; Rizzo, A; Rosner, G; Roy, P; Sabatié, F; Saini, M S; Schott, D; Schumacher, R A; Simonyan, A; Sokhan, D; Strauch, S; Sytnik, V; Tang, W; Tian, Ye; Ungaro, M; Vernarsky, B; Vlassov, A V; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Weinstein, L B; Wood, M H; Zachariou, N; Zhang, J; Zhao, Z W; Zonta, I

    2014-10-10

    We measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK(+), pπ(0), and nπ(+), with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq creation probabilities for the first time in exclusive two-body production, in which only a single qq pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

  13. Extracting nucleon strange and anapole form factors from data

    SciTech Connect

    R.D. Young; J. Roche; R.D. Carlini; A.W. Thomas

    2006-04-14

    Using the complete world set of parity violating electron scattering data up to Q{sup 2} {approx} 0.3 GeV{sup 2}, we extract the current best determination of the strange electric and magnetic form factors of the proton, as well as the weak axial form factors of the proton and neutron at Q{sup 2} = 0.1 GeV{sup 2}. The results are consistent with state of the art calculations of all four form factors, with the latter including the anapole contribution.

  14. Connected, disconnected and strange quark contributions to HVP

    NASA Astrophysics Data System (ADS)

    Bijnens, Johan; Relefors, Johan

    2016-11-01

    We calculate all neutral vector two-point functions in Chiral Perturbation Theory (ChPT) to two-loop order and use these to estimate the ratio of disconnected to connected contributions as well as contributions involving the strange quark. We extend the ratio of -1/10 derived earlier in two flavour ChPT at one-loop order to a large part of the higher order contributions and discuss corrections to it. Our final estimate of the ratio disconnected to connected is negative and a few % in magnitude.

  15. Using the Moon As A Low-Noise Seismic Detector For Strange Quark Nuggets

    NASA Technical Reports Server (NTRS)

    Banerdt, W. Bruce; Chui, Talso; Griggs, Cornelius E.; Herrin, Eugene T.; Nakamura, Yosio; Paik, Ho Jung; Penanen, Konstantin; Rosenbaum, Doris; Teplitz, Vigdor L.; Young, Joseph

    2006-01-01

    Strange quark matter made of up, down and strange quarks has been postulated by Witten [1]. Strange quark matter would be nearly charge neutral and would have density of nuclear matter (10(exp 14) gm/cu cm). Witten also suggested that nuggets of strange quark matter, or strange quark nuggets (SQNs), could have formed shortly after the Big Bang, and that they would be viable candidates for cold dark matter. As suggested by de Rujula and Glashow [2], an SQN may pass through a celestial body releasing detectable seismic energy along a straight line. The Moon, being much quieter seismically than the Earth, would be a favorable place to search for such events. We review previous searches for SQNs to illustrate the parameter space explored by using the Moon as a low-noise detector of SQNs. We also discuss possible detection schemes using a single seismometer, and using an International Lunar Seismic Network.

  16. Using the Moon As A Low-Noise Seismic Detector For Strange Quark Nuggets

    NASA Technical Reports Server (NTRS)

    Banerdt, W. Bruce; Chui, Talso; Griggs, Cornelius E.; Herrin, Eugene T.; Nakamura, Yosio; Paik, Ho Jung; Penanen, Konstantin; Rosenbaum, Doris; Teplitz, Vigdor L.; Young, Joseph

    2006-01-01

    Strange quark matter made of up, down and strange quarks has been postulated by Witten [1]. Strange quark matter would be nearly charge neutral and would have density of nuclear matter (10(exp 14) gm/cu cm). Witten also suggested that nuggets of strange quark matter, or strange quark nuggets (SQNs), could have formed shortly after the Big Bang, and that they would be viable candidates for cold dark matter. As suggested by de Rujula and Glashow [2], an SQN may pass through a celestial body releasing detectable seismic energy along a straight line. The Moon, being much quieter seismically than the Earth, would be a favorable place to search for such events. We review previous searches for SQNs to illustrate the parameter space explored by using the Moon as a low-noise detector of SQNs. We also discuss possible detection schemes using a single seismometer, and using an International Lunar Seismic Network.

  17. Measurement of strange particle production in the NICA fixed-target programme

    NASA Astrophysics Data System (ADS)

    Friese, Volker

    2016-08-01

    Strange particles provide a sensitive tool to study the dense and hot matter created in relativistic nuclear collisions. Although strangeness production in such collisions has been a topic of experimental and theoretical research for many years, its understanding is far from being complete. This holds in particular for multi-strange hyperons and for lower collision energies as relevant for NICA and FAIR. Multi-strange particles, being sensitive to both the mechanism of strangeness production and the net-baryon density, are expected to shed light on the state of the created matter and to indicate possible transitions to new phases of strongly interacting matter. We thus advocate the measurement of hyperons and φ mesons in a fixed-target experiment at NICA (BM@N), which can be achieved by a relatively compact detector system.

  18. Genetic reincarnation of workers as queens in the Eastern honeybee Apis cerana

    PubMed Central

    Holmes, M J; Tan, K; Wang, Z; Oldroyd, B P; Beekman, M

    2015-01-01

    Thelytokous parthenogenesis, or the asexual production of female offspring, is rare in the animal kingdom, but relatively common in social Hymenoptera. However, in honeybees, it is only known to be ubiquitous in one subspecies of Apis mellifera, the Cape honeybee, A. mellifera capensis. Here we report the appearance of queen cells in two colonies of the Eastern honeybee Apis cerana that no longer contained a queen or queen-produced brood to rear queens from. A combination of microsatellite genotyping and the timing of the appearance of these individuals excluded the possibility that they had been laid by the original queen. Based on the genotypes of these individuals, thelytokous production by natal workers is the most parsimonious explanation for their existence. Thus, we present the first example of thelytoky in a honeybee outside A. mellifera. We discuss the evolutionary and ecological consequences of thelytoky in A. cerana, in particular the role thelytoky may play in the recent invasions by populations of this species. PMID:25052414

  19. Sequential palynostratigraphy of the Queen City and Weches formations (Middle Eocene Claiborne Group), southeast central Texas

    SciTech Connect

    Elsik, W.C. )

    1993-02-01

    Palynomorph sequences of several orders of magnitude were found in the Queen City and Weches formations respectively at Six Mile and Burleson bluffs on the Brazos River, Milam and Burleson counties, Texas. The long term development of the subtropical to tropical Claibornian palynoflora included Engelhardtia spp., Friedrichipollis claibornensis, Nudopollis terminalis, Pollenites laesius and Symplocoipollenites spp. Shorter term fluctuations in sea level were reflected by common herbaceous pollen in the Queen City, and common mangrove pollen in the Weches. Paleoenvironments were marginally to fully marine; dinocysts occurred throughout. The Wetzeliella group of dinocysts were present only in the Queen City at Six Mile Bluff. Late Paleocene to Early Eocene pollen, and Early Middle Eocene pollen with last effective occurrences near the Queen City and Weches boundary included Aesculiidites circumstriatus, Annona foveoreticulata and a new species of Platycarya. Five short term warmer-cooler couplet events were represented by successive abundance peaks of Juglandaceae followed by Ulmus; Alnus supports the three upper Ulmus peaks. One deep water event was recorded by an abundance of fresh water Pediastrum at the Queen City and Weches boundary. That boundary event was bracketed by two of the Alnus and Ulmus peaks.

  20. Winged queens replaced by reproductives smaller than workers in Mystrium ants

    NASA Astrophysics Data System (ADS)

    Molet, Mathieu; Peeters, Christian; Fisher, Brian L.

    2007-04-01

    In ants, winged queens that are specialized for independent colony foundation can be replaced by wingless reproductives better adapted for colony fission. We studied this shift in reproductive strategy by comparing two Mystrium species from Madagascar using morphometry, allometry and dissections. Mystrium rogeri has a single dealate queen in each colony with a larger thorax than workers and similar mandibles that allow these queens to hunt during non-claustral foundation. In contrast, Mystrium ‘red’ lacks winged queens and half of the female adults belong to a wingless ‘intermorph’ caste smaller and allometrically distinct from the workers. Intermorphs have functional ovaries and spermatheca while those of workers are degenerate. Intermorphs care for brood and a few mate and reproduce making them an all-purpose caste that takes charge of both work and reproduction. However, their mandibles are reduced and inappropriate for hunting centipedes, unlike the workers’ mandibles. This together with their small thorax disallow them to perform independent colony foundation, and colonies reproduce by fission. M. rogeri workers have mandibles polymorphic in size and shape, which allow for all tasks from brood care to hunting. In M. ‘red’, colonial investment in reproduction has shifted from producing expensive winged queens to more numerous helpers. M. ‘red’ intermorphs are the first case of reproductives smaller than workers in ants and illustrate their potential to diversify their caste system for better colonial economy.

  1. When invasive ants meet: effects of outbreeding on queen performance in the tramp ant Cardiocondyla itsukii.

    PubMed

    Heinze, Jürgen; Frohschammer, Sabine; Bernadou, Abel

    2017-08-18

    Most disturbed habitats in the tropics and subtropics harbor numerous species of invasive ants, and occasionally the same species has been introduced repeatedly from multiple geographical sources. We examined how experimental crossbreeding between sexuals from different populations affects the fitness of queens of the tramp ant Cardiocondyla itsukii, which is widely distributed in Asia and the Pacific Islands. Eggs laid by queens that mated with nestmate males had a higher hatching rate than eggs laid by queens mated to males from neighboring (Hawaii x Kauai) or distant introduced populations (Hawaii / Kauai x Okinawa). Furthermore, inbreeding queens had a longer lifespan and produced a less female-biased offspring sex ratio than queens from allopatric mating. This suggests that the genetic divergence between different source populations may already be so large that in case of multiple invasions eventual crossbreeding might negatively affect the fitness of tramp ants. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  2. Hydrologic data for the Usquepaug-Queen River basin, Rhode Island

    USGS Publications Warehouse

    Kliever, John D.

    1995-01-01

    The Usquepaug-Queen River ground-water reservoir in Rhode Island is part of the stratified-drift aquifer along the Usquepaug-Queen River and its tributaries. The thickest, most permeable parts of the aquifer form the Usquepaug-Queen River ground-water reservoir. The 36.1-square mile study area comprises parts of Washington and Kent counties, and includes parts of the towns of Exeter, North Kingstown, Richmond, South Kingstown, and West Greenwich. The report presents geologic and hydrologic information needed for the prediction and management of hydrologic effects of proposed ground-water development. The report describes aquifer lithology, provides historical data on water-level and aquifer-storage changes, provides information on ground-water quality, and presents natural flow characteristics and water quality of streams in the Usquepaug-Queen River area. The data includes 275 ground-water sites; lithologic logs of 66 ground-water sites; water levels for 43 ground- water sites; chemical analyses of 36 ground-water sites; stream discharge measurements from the continuous-record gaging station on the Usquepaug- Queen River; discharge measurements at 10 partial- record stations in the area; chemical analyses of 17 stream sites; and the data from 14 slug tests conducted at ground-water sites.

  3. Measuring inotocin receptor gene expression in chronological order in ant queens.

    PubMed

    Chérasse, Sarah; Aron, Serge

    2017-09-24

    In vertebrates and invertebrates, oxytocin/vasopressin-like peptides modulate a variety of behaviors. The recent discovery of the gene and receptor sequences of inotocin, the insect ortholog of oxytocin/vasopressin, opens new opportunities for understanding the role of this peptide family in regulating behaviors in the most populated class of living animals. Ants live in highly organized colonies. Once a year, they produce future queens that soon leave the nest to mate and found new colonies. During the first months of their lives, ant queens display a sequence of behaviors ranging from copulation and social interactions to violent fighting. In order to investigate the potential roles of inotocin in shaping queen behavior, we measured gene expression of the inotocin receptor in the heads of Lasius niger ant queens at different points in time. The highest levels of expression occurred early in queen life when they experience crowded conditions in their mother nests and soon thereafter set out to mate. Inotocin could thus be involved in regulating social and reproductive behaviors as reported in other animals. While oxytocin and vasopressin are also involved in aggression in mammals, we found no direct link between these behaviors and inotocin receptor expression in L. niger. Our study provides a first glimpse into the roles the inotocin receptor might play in regulating important processes in ant physiology and behavior. Further studies are needed to understand the molecular function of this complex signaling system in more detail. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Transpression between two warm mafic plates: The Queen Charlotte Fault revisited

    NASA Astrophysics Data System (ADS)

    Rohr, Kristin M. M.; Scheidhauer, Maren; Trehu, Anne M.

    2000-04-01

    The Queen Charlotte Fault is a transpressive transform plate boundary between the Pacific and North American plates offshore western Canada. Previous models for the accommodation of transpression include internal deformation of both plates adjacent to the plate boundary or oblique subduction of the oceanic plate; the latter has been the preferred model. Both plates are warm and mafic and have similar mechanical structures. New multichannel seismic reflection data show a near-vertical Queen Charlotte Fault down to the first water bottom multiple, significant subsidence east of the Queen Charlotte Fault, a large melange where the fault is in a compressive left step, and faulting which involves oceanic basement. Gravity modeling of profiles indicates that Moho varies fairly smoothly across the plate boundary. Isostatic anomalies indicate that the Pacific plate is flexed downward adjacent to the Queen Charlotte Fault. Upward flexure of North America along with crust thickened relative to crust in the adjacent basin creates topography known as the Queen Charlotte Islands. Combined with other regional studies, these observations suggest that the plate boundary is a vertical strike-slip fault and that transpression is taken up within each plate.

  5. Modelling information exchange in worker–queen conflict over sex allocation

    PubMed Central

    Pen, Ido; Taylor, Peter D

    2005-01-01

    We investigate the conflict between queen and worker over sex allocation, specifically the allocation of the queen's eggs between workers and reproductives and the allocation of the reproductive eggs between male and female. In contrast to previous models, we allow workers to observe and use information about the strategy of the queen. We consider three conflict models: simultaneous (no information exchange), sequential (a one-way information exchange) and negotiated (an iterated two-way information exchange). We find that the first model produces sex ratios intermediate between the classic queen (1 : 1) and worker (1 : 3) optima. The second model, in which the worker has information about the queen's decisions, produces a different result and one that is somewhat counter-intuitive in that the sex ratios are less female-biased than for the other two models, and in fact are often male-biased. The third model predicts sex ratios intermediate between the first two models. We discuss how these findings may shed new light on observed sex allocation patterns in social insects and we suggest some experimental tests. PMID:16243692

  6. Imaging and spectroscopic observations of a strange elliptical bubble in the northern arm of the spiral galaxy NGC 6946

    NASA Astrophysics Data System (ADS)

    Efremov, Yuri N.; Moiseev, Alexei V.

    2016-09-01

    NGC 6946, known as the Fireworks galaxy because of its high supernova rate and high star formation, is embedded in a very extended H I halo. Its northern spiral arm is well detached from the galactic main body. We found that this arm contains a large (˜300 pc in size) Red Ellipse, named according to a strong contamination of the Hα emission line on its optical images. The ellipse is accompanied by a short parallel arc and a few others still smaller and less regular; a bright star cluster is seen inside these features. The complicated combination of arcs seems to be unique; it is only a bit similar to some SNRs. However, the long-slit spectral data obtained with the Russian 6-m telescope did not confirm the origin of the nebula as a result of a single SN outburst. The emission-line spectrum corresponds to the photoionization by young hot stars with a small contribution of shock ionization. The most likely explanation of the Red Ellipse is a superbubble created by a collective feedback of massive stars in the star cluster located in the NE side of the Red Ellipse. However, the very regular elliptical shape of the nebulae seems strange.

  7. Comparing alternative methods for holding virgin honey bee queens for one week in mailing cages before mating.

    PubMed

    Bigio, Gianluigi; Grüter, Christoph; Ratnieks, Francis L W

    2012-01-01

    In beekeeping, queen honey bees are often temporarily kept alive in cages. We determined the survival of newly-emerged virgin honey bee queens every day for seven days in an experiment that simultaneously investigated three factors: queen cage type (wooden three-hole or plastic), attendant workers (present or absent) and food type (sugar candy, honey, or both). Ten queens were tested in each of the 12 combinations. Queens were reared using standard beekeeping methods (Doolittle/grafting) and emerged from their cells into vials held in an incubator at 34C. All 12 combinations gave high survival (90 or 100%) for three days but only one method (wooden cage, with attendants, honey) gave 100% survival to day seven. Factors affecting queen survival were analysed. Across all combinations, attendant bees significantly increased survival (18% vs. 53%, p<0.001). In addition, there was an interaction between food type and cage type (p<0.001) with the honey and plastic cage combination giving reduced survival. An additional group of queens was reared and held for seven days using the best method, and then directly introduced using smoke into queenless nucleus colonies that had been dequeened five days previously. Acceptance was high (80%, 8/10) showing that this combination is also suitable for preparing queens for introduction into colonies. Having a simple method for keeping newly-emerged virgin queens alive in cages for one week and acceptable for introduction into queenless colonies will be useful in honey bee breeding. In particular, it facilitates the screening of many queens for genetic or phenotypic characteristics when only a small proportion meets the desired criteria. These can then be introduced into queenless hives for natural mating or insemination, both of which take place when queens are one week old.

  8. Tolerating an infection: an indirect benefit of co-founding queen associations in the ant Lasius niger

    NASA Astrophysics Data System (ADS)

    Pull, Christopher D.; Hughes, William O. H.; Brown, Mark J. F.

    2013-12-01

    Pathogens exert a strong selection pressure on organisms to evolve effective immune defences. In addition to individual immunity, social organisms can act cooperatively to produce collective defences. In many ant species, queens have the option to found a colony alone or in groups with other, often unrelated, conspecifics. These associations are transient, usually lasting only as long as each queen benefits from the presence of others. In fact, once the first workers emerge, queens fight to the death for dominance. One potential advantage of co-founding may be that queens benefit from collective disease defences, such as mutual grooming, that act against common soil pathogens. We test this hypothesis by exposing single and co-founding queens to a fungal parasite, in order to assess whether queens in co-founding associations have improved survival. Surprisingly, co-foundresses exposed to the entomopathogenic fungus Metarhizium did not engage in cooperative disease defences, and consequently, we find no direct benefit of multiple queens on survival. However, an indirect benefit was observed, with parasite-exposed queens producing more brood when they co-founded, than when they were alone. We suggest this is due to a trade-off between reproduction and immunity. Additionally, we report an extraordinary ability of the queens to tolerate an infection for long periods after parasite exposure. Our study suggests that there are no social immunity benefits for co-founding ant queens, but that in parasite-rich environments, the presence of additional queens may nevertheless improve the chances of colony founding success.

  9. An almost symmetric Strang splitting scheme for nonlinear evolution equations☆

    PubMed Central

    Einkemmer, Lukas; Ostermann, Alexander

    2014-01-01

    In this paper we consider splitting methods for the time integration of parabolic and certain classes of hyperbolic partial differential equations, where one partial flow cannot be computed exactly. Instead, we use a numerical approximation based on the linearization of the vector field. This is of interest in applications as it allows us to apply splitting methods to a wider class of problems from the sciences. However, in the situation described, the classic Strang splitting scheme, while still being a method of second order, is not longer symmetric. This, in turn, implies that the construction of higher order methods by composition is limited to order three only. To remedy this situation, based on previous work in the context of ordinary differential equations, we construct a class of Strang splitting schemes that are symmetric up to a desired order. We show rigorously that, under suitable assumptions on the nonlinearity, these methods are of second order and can then be used to construct higher order methods by composition. In addition, we illustrate the theoretical results by conducting numerical experiments for the Brusselator system and the KdV equation. PMID:25844017

  10. Characterization of noise-induced strange nonchaotic attractors.

    PubMed

    Wang, Xingang; Lai, Ying-Cheng; Lai, Choy Heng

    2006-07-01

    Strange nonchaotic attractors (SNAs) were previously thought to arise exclusively in quasiperiodic dynamical systems. A recent study has revealed, however, that such attractors can be induced by noise in nonquasiperiodic discrete-time maps or in periodically driven flows. In particular, in a periodic window of such a system where a periodic attractor coexists with a chaotic saddle (nonattracting chaotic invariant set), none of the Lyapunov exponents of the asymptotic attractor is positive. Small random noise is incapable of causing characteristic changes in the Lyapunov spectrum, but it can make the attractor geometrically strange by dynamically connecting the original periodic attractor with the chaotic saddle. Here we present a detailed study of noise-induced SNAs and the characterization of their properties. Numerical calculations reveal that the fractal dimensions of noise-induced SNAs typically assume fractional values, in contrast to SNAs in quasiperiodically driven systems whose dimensions are integers. An interesting finding is that the fluctuations of the finite-time Lyapunov exponents away from their asymptotic values obey an exponential distribution, the generality of which we are able to establish by a theoretical analysis using random matrices. We suggest a possible experimental test. We expect noise-induced SNAs to be general.

  11. Detectability of strange matter in heavy ion experiments

    SciTech Connect

    Schaffner, J., ||; Diener, A.; Stocker, H.,; Greiner, C.,

    1997-06-01

    We discuss the properties of two distinct forms of hypothetical strange matter, small lumps of strange quark matter (strangelets) and of hyperon matter [metastable exotic multihypernuclear objects (MEMO{close_quote}s)], with special emphasis on their relevance for present and future heavy ion experiments. The masses of small strangelets up to A{sub B}=40 are calculated using the MIT bag model with shell mode filling for various bag parameters. The strangelets are checked for possible strong and weak hadronic decays, also taking into account multiple hadron decays. It is found that strangelets which are stable against strong decay are most likely highly negatively charged, contrary to previous findings. Strangelets can be stable against weak hadronic decay but their masses and charges are still rather high. This has serious impact on the present high sensitivity searches in heavy ion experiments at the AGS and CERN facilities. On the other hand, highly charged MEMO{close_quote}s are predicted on the basis of an extended relativistic mean-field model. Those objects could be detected in future experiments searching for short-lived, rare composites. It is demonstrated that future experiments can be sensitive to a much wider variety of strangelets. {copyright} {ital 1997} {ital The American Physical Society}

  12. An almost symmetric Strang splitting scheme for nonlinear evolution equations.

    PubMed

    Einkemmer, Lukas; Ostermann, Alexander

    2014-07-01

    In this paper we consider splitting methods for the time integration of parabolic and certain classes of hyperbolic partial differential equations, where one partial flow cannot be computed exactly. Instead, we use a numerical approximation based on the linearization of the vector field. This is of interest in applications as it allows us to apply splitting methods to a wider class of problems from the sciences. However, in the situation described, the classic Strang splitting scheme, while still being a method of second order, is not longer symmetric. This, in turn, implies that the construction of higher order methods by composition is limited to order three only. To remedy this situation, based on previous work in the context of ordinary differential equations, we construct a class of Strang splitting schemes that are symmetric up to a desired order. We show rigorously that, under suitable assumptions on the nonlinearity, these methods are of second order and can then be used to construct higher order methods by composition. In addition, we illustrate the theoretical results by conducting numerical experiments for the Brusselator system and the KdV equation.

  13. Comparing Two Attachment Classification Methods Applied to Preschool Strange Situations

    PubMed Central

    Spieker, Susan; Crittenden, Patricia Mckinsey

    2013-01-01

    This study compared two methods for classifying preschool-age children's behavior in the Strange Situation procedure, the MacArthur (MAC) and the Preschool Assessment of Attachment (PAA), to determine whether they operationalized converging or diverging approaches to attachment theory. Strange Situations of 306 randomly selected 3-year-old children and their mothers in the NICHD Study of Early Child Care and Youth Development were classified with the MAC and PAA. The methods showed 50% agreement. A block of seven demographic, child and family predictors was unrelated to MAC classifications, but accounted for 19% of the variance in PAA classifications. The MAC and PAA each had associations with some child outcomes in grades 1-5 (ages 6-10) totalling 5% and 12% of the variance respectively, but some of the MAC associations were counter to the hypothesis. The MAC and PAA were sufficiently different to reflect both different classificatory methods and different theoretical understandings of attachment. Results are discussed in terms of limitations of the sample and measures available to compare the two methods, and clinical implications. PMID:19914941

  14. Electroproduction of baryon-meson states and strangeness suppression

    NASA Astrophysics Data System (ADS)

    Santopinto, E.; García-Tecocoatzi, H.; Bijker, R.

    2016-08-01

    We describe the electroproduction ratios of baryon-meson states from nucleon, inferring from the sea quarks in the nucleon using an extension of the quark model that takes into account the sea. As a result we provide, with no adjustable parameters, the predictions of ratios of exclusive meson-baryon final states: ΛK+, Σ* K, ΣK, pπ0, and nπ+. These predictions are in agreement with the new JLab experimental data showing that sea quarks play an important role in the electroproduction. We also predicted further ratios of exclusive reactions that can be measured and tested in future experiments. In particular, we suggested new experiments on deuterium and tritium. Such measurements can provide crucial tests of different predictions concerning the structure of nucleon and its sea quarks helping to solve an outstanding problem. Finally, we compute the so called strangeness suppression factor, λs, that is the suppression of strange quark-antiquark pairs compared to nonstrange pairs, and we found that our finding with this simple extension of the quark model is in good agreement with the results of JLab and CERN experiments.

  15. Can doubly strange dibaryon resonances be discovered at RHIC?

    SciTech Connect

    Paganis, S. D.; Hoffmann, G. W.; Ray, R. L.; Tang, J.-L.; Udagawa, T.; Longacre, R. S.

    2000-08-01

    The baryon-baryon continuum invariant mass spectrum generated from relativistic nucleus + nucleus collision data may reveal the existence of doubly strange dibaryons not stable against strong decay if they lie within a few MeV of threshold. Furthermore, since the dominant component of these states is a superposition of two color-octet clusters which can be produced intermediately in a color-deconfined quark-gluon plasma (QGP), an enhanced production of dibaryon resonances could be a signal of QGP formation. A total of eight, doubly strange dibaryon states are considered for experimental search using the STAR detector (solenoidal tracker at RHIC) at the new Relativistic Heavy Ion Collider (RHIC). These states may decay to {lambda}{lambda} and/or p{xi}{sup -}, depending on the resonance energy. STAR's large acceptance, precision tracking and vertex reconstruction capabilities, and large data volume capacity, make it an ideal instrument to use for such a search. Detector performance and analysis sensitivity are studied as a function of resonance production rate and width for one particular dibaryon which can directly strong decay to p{xi}{sup -}, but not {lambda}{lambda}. Results indicate that such resonances may be discovered using STAR if the resonance production rates are comparable to coalescence model predictions for dibaryon bound states. (c) 2000 The American Physical Society.

  16. "Making strange": a role for the humanities in medical education.

    PubMed

    Kumagai, Arno K; Wear, Delese

    2014-07-01

    Stories, film, drama, and art have been used in medical education to enhance empathy, perspective-taking, and openness to "otherness," and to stimulate reflection on self, others, and the world. Yet another, equally important function of the humanities and arts in the education of physicians is that of "making strange"-that is, portraying daily events, habits, practices, and people through literature and the arts in a way that disturbs and disrupts one's assumptions, perspectives, and ways of acting so that one sees the self, others, and the world anew. Tracing the development of this concept from Viktor Shklovsky's "enstrangement" (ostranenie) through Bertolt Brecht's "alienation effect," this essay describes the use of this technique to disrupt the "automaticity of thinking" in order to discover new ways of perceiving and being in the world.Enstrangement may be used in medical education in order to stimulate critical reflection and dialogue on assumptions, biases, and taken-for-granted societal conditions that may hinder the realization of a truly humanistic clinical practice. In addition to its ability to enhance one's critical understanding of medicine, the technique of "making strange" does something else: By disrupting fixed beliefs, this approach may allow a reexamination of patient-physician relationships in terms of human interactions and provide health care professionals an opportunity-an "open space"-to bear witness and engage with other individuals during challenging times.

  17. Impact of imidacloprid on new queens of imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae)

    PubMed Central

    Wang, Lei; Zeng, Ling; Chen, Jian

    2015-01-01

    Neonicotinoid insecticides are commonly used in managing pest insects, including the imported fire ant, Solenopsis invicta Buren. There is increasing evidence that neonicotinoid insecticides at sublethal concentrations have profound effects on social insects. However, the sublethal effect of neonicotinoids on S. invicta has never been investigated. In this study, the newly mated queens were fed with water containing 0.01 or 0.25 μg/ml imidacloprid. Imidacloprid at both concentrations did not cause any increase in queen mortality during the founding stage; however, it significantly reduced queens’ brood tending ability. In the 0.25 μg/ml imidacloprid treatment, the time to larval emergence was significantly delayed and no pupae or adult workers were produced. This study provides clear evidence that imidacloprid at sublethal concentrations has a significant detrimental impact on S. invicta queens and the development of incipient colonies. PMID:26643971

  18. Localization of deformed wing virus infection in queen and drone Apis mellifera L.

    PubMed

    Fievet, Julie; Tentcheva, Diana; Gauthier, Laurent; de Miranda, Joachim; Cousserans, François; Colin, Marc Edouard; Bergoin, Max

    2006-03-28

    The distribution of deformed wing virus infection within the honey bee reproductive castes (queens, drones) was investigated by in situ hybridization and immunohistology from paraffin embedded sections. Digoxygenin or CY5.5 fluorochrome end-labelled nucleotide probes hybridizing to the 3' portion of the DWV genome were used to identify DWV RNA, while a monospecific antibody to the DWV-VP1 structural protein was used to identify viral proteins and particles. The histological data were confirmed by quantitative RT-PCR of dissected organs. Results showed that DWV infection is not restricted to the digestive tract of the bee but spread in the whole body, including queen ovaries, queen fat body and drone seminal vesicles.

  19. Localization of deformed wing virus infection in queen and drone Apis mellifera L

    PubMed Central

    Fievet, Julie; Tentcheva, Diana; Gauthier, Laurent; de Miranda, Joachim; Cousserans, François; Colin, Marc Edouard; Bergoin, Max

    2006-01-01

    The distribution of deformed wing virus infection within the honey bee reproductive castes (queens, drones) was investigated by in situ hybridization and immunohistology from paraffin embedded sections. Digoxygenin or CY5.5 fluorochrome end-labelled nucleotide probes hybridizing to the 3' portion of the DWV genome were used to identify DWV RNA, while a monospecific antibody to the DWV-VP1 structural protein was used to identify viral proteins and particles. The histological data were confirmed by quantitative RT-PCR of dissected organs. Results showed that DWV infection is not restricted to the digestive tract of the bee but spread in the whole body, including queen ovaries, queen fat body and drone seminal vesicles. PMID:16569216

  20. Behavioural development, fat reserves and their association with productivity in Lasius flavus founding queens

    NASA Astrophysics Data System (ADS)

    Norman, V. C.; Pamminger, T.; Hughes, W. O. H.

    2016-04-01

    Reproduction-related behaviours are key components determining individual fitness. Many behavioural traits are linked, and such trait associations often affect fitness. Here, we combine behavioural and physiological data during two critical time points of founding queens (early and late nest-founding stage) in the claustral ant Lasius flavus to assess how these factors affect their initial productivity. We show that most behavioural traits, except brood care behaviour, are plastic during queen development and demonstrate that there are alternative behavioural pathways to achieve high productivity under standardised conditions. These results indicate that queens can utilise multiple behavioural trait combinations to maximise reproductive output at the earliest, and arguably most critical, time of colony foundation.