Diversity and specificity in the interaction between Caenorhabditis elegans and the pathogen Serratia marcescens.

PubMed

Schulenburg, Hinrich; Ewbank, Jonathan J

2004-11-22

Co-evolutionary arms races between parasites and hosts are considered to be of immense importance in the evolution of living organisms, potentially leading to highly dynamic life-history changes. The outcome of such arms races is in many cases thought to be determined by frequency dependent selection, which relies on genetic variation in host susceptibility and parasite virulence, and also genotype-specific interactions between host and parasite. Empirical evidence for these two prerequisites is scarce, however, especially for invertebrate hosts. We addressed this topic by analysing the interaction between natural isolates of the soil nematode Caenorhabditis elegans and the pathogenic soil bacterium Serratia marcescens. Our analysis reveals the presence of i) significant variation in host susceptibility, ii) significant variation in pathogen virulence, and iii) significant strain- and genotype-specific interactions between the two species. The results obtained support the previous notion that highly specific interactions between parasites and animal hosts are generally widespread. At least for C. elegans, the high specificity is observed among isolates from the same population, such that it may provide a basis for and/or represent the outcome of co-evolutionary adaptations under natural conditions. Since both C. elegans and S. marcescens permit comprehensive molecular analyses, these two species provide a promising model system for inference of the molecular basis of such highly specific interactions, which are as yet unexplored in invertebrate hosts.

Diversity and specificity in the interaction between Caenorhabditis elegans and the pathogen Serratia marcescens

PubMed Central

Schulenburg, Hinrich; Ewbank, Jonathan J

2004-01-01

Background Co-evolutionary arms races between parasites and hosts are considered to be of immense importance in the evolution of living organisms, potentially leading to highly dynamic life-history changes. The outcome of such arms races is in many cases thought to be determined by frequency dependent selection, which relies on genetic variation in host susceptibility and parasite virulence, and also genotype-specific interactions between host and parasite. Empirical evidence for these two prerequisites is scarce, however, especially for invertebrate hosts. We addressed this topic by analysing the interaction between natural isolates of the soil nematode Caenorhabditis elegans and the pathogenic soil bacterium Serratia marcescens. Results Our analysis reveals the presence of i) significant variation in host susceptibility, ii) significant variation in pathogen virulence, and iii) significant strain- and genotype-specific interactions between the two species. Conclusions The results obtained support the previous notion that highly specific interactions between parasites and animal hosts are generally widespread. At least for C. elegans, the high specificity is observed among isolates from the same population, such that it may provide a basis for and/or represent the outcome of co-evolutionary adaptations under natural conditions. Since both C. elegans and S. marcescens permit comprehensive molecular analyses, these two species provide a promising model system for inference of the molecular basis of such highly specific interactions, which are as yet unexplored in invertebrate hosts. PMID:15555070

Strategic variation in mobbing as a front line of defense against brood parasitism.

PubMed

Welbergen, Justin A; Davies, Nicholas B

2009-02-10

Coevolutionary arms races, where adaptations in one party select for counter-adaptations in another and vice versa, are fundamental to interactions between organisms and their predators, pathogens, and parasites [1]. Avian brood parasites and their hosts have emerged as model systems for studying such reciprocal coevolutionary processes [2, 3]. For example, hosts have evolved changes in egg appearance and rejection of foreign eggs in response to brood parasitism from cuckoos, and cuckoos have evolved host-egg mimicry as a counter-response [4-6]. However, the host's front line of defense is protecting the nest from being parasitized in the first place [7-10], yet little is known about the effectiveness of nest defense as an antiparasite adaptation, and its coevolutionary significance remains poorly understood [10]. Here we show first that mobbing of common cuckoos Cuculus canorus by reed warblers Acrocephalus scirpaceus is an effective defense against parasitism. Second, mobbing of cuckoos is a phenotypically plastic trait that is modified strategically according to local parasitism risk. This supports the view that hosts use a "defense in-depth strategy," with successive flexible lines of defense that coevolve with corresponding offensive lines of the parasite. This highlights the need for more holistic research into the coevolutionary consequences when multiple adaptations and counter-adaptations evolve in concert [11].

A quantitative trait locus for recognition of foreign eggs in the host of a brood parasite.

PubMed

Martín-Gálvez, D; Soler, J J; Martínez, J G; Krupa, A P; Richard, M; Soler, M; Møller, A P; Burke, T

2006-03-01

Avian brood parasites reduce the reproductive output of their hosts and thereby select for defence mechanisms such as ejection of parasitic eggs. Such defence mechanisms simultaneously select for counter-defences in brood parasites, causing a coevolutionary arms race. Although coevolutionary models assume that defences and counter-defences are genetically influenced, this has never been demonstrated for brood parasites. Here, we give strong evidence for genetic differences between ejector and nonejectors, which could allow the study of such host defence at the genetic level, as well as studies of maintenance of genetic variation in defences. Briefly, we found that magpies, that are the main host of the great spotted cuckoo in Europe, have alleles of one microsatellite locus (Ase64) that segregate between accepters and rejecters of experimental parasitic eggs. Furthermore, differences in ejection rate among host populations exploited by the brood parasite covaried significantly with the genetic distance for this locus.

Coevolution in host-parasite systems: behavioural strategies of slave-making ants and their hosts.

PubMed

Foitzik, S; DeHeer, C J; Hunjan, D N; Herbers, J M

2001-06-07

Recently, avian brood parasites and their hosts have emerged as model systems for the study of host-parasite coevolution. However, empirical studies of the highly analogous social parasites, which use the workers of another eusocial species to raise their own young, have never explicitly examined the dynamics of these systems from a coevolutionary perspective. Here, we demonstrate interpopulational variation in behavioural interactions between a socially parasitic slave-maker ant and its host that is consistent with the expectations of host-parasite coevolution. Parasite pressure, as inferred by the size, abundance and raiding frequency of Protomognathus americanus colonies, was highest in a New York population of the host Leptothorax longispinosus and lowest in a West Virginia population. As host-parasite coevolutionary theory would predict, we found that the slave-makers and the hosts from New York were more effective at raiding and defending against raiders, respectively, than were conspecifics from the West Virginia population. Some of these variations in efficacy were brought about by apparently simple shifts in behaviour. These results demonstrate that defence mechanisms against social parasites can evolve, and they give the first indications of the existence of a coevolutionary arms race between a social parasite and its host.

Brood parasitism selects for no defence in a cuckoo host

PubMed Central

Krüger, Oliver

2011-01-01

In coevolutionary arms races, like between cuckoos and their hosts, it is easy to understand why the host is under selection favouring anti-parasitism behaviour, such as egg rejection, which can lead to parasites evolving remarkable adaptations to ‘trick’ their host, such as mimetic eggs. But what about cases where the cuckoo egg is not mimetic and where the host does not act against it? Classically, such apparently non-adaptive behaviour is put down to evolutionary lag: given enough time, egg mimicry and parasite avoidance strategies will evolve. An alternative is that absence of egg mimicry and of anti-parasite behaviour is stable. Such stability is at first sight highly paradoxical. I show, using both field and experimental data to parametrize a simulation model, that the absence of defence behaviour by Cape bulbuls (Pycnonotus capensis) against parasitic eggs of the Jacobin cuckoo (Clamator jacobinus) is optimal behaviour. The cuckoo has evolved massive eggs (double the size of bulbul eggs) with thick shells, making it very hard or impossible for the host to eject the cuckoo egg. The host could still avoid brood parasitism by nest desertion. However, higher predation and parasitism risks later in the season makes desertion more costly than accepting the cuckoo egg, a strategy aided by the fact that many cuckoo eggs are incorrectly timed, so do not hatch in time and hence do not reduce host fitness to zero. Selection will therefore prevent the continuation of any coevolutionary arms race. Non-mimetic eggs and absence of defence strategies against cuckoo eggs will be the stable, if at first sight paradoxical, result. PMID:21288944

Sexual selection modulates genetic conflicts and patterns of genomic imprinting

PubMed Central

Faria, Gonçalo S.; Varela, Susana A. M.; Gardner, Andy

2017-01-01

Recent years have seen a surge of interest in linking the theories of kin selection and sexual selection. In particular, there is a growing appreciation that kin selection, arising through demographic factors such as sex‐biased dispersal, may modulate sexual conflicts, including in the context of male–female arms races characterized by coevolutionary cycles. However, evolutionary conflicts of interest need not only occur between individuals, but may also occur within individuals, and sex‐specific demography is known to foment such intragenomic conflict in relation to social behavior. Whether and how this logic holds in the context of sexual conflict—and, in particular, in relation to coevolutionary cycles—remains obscure. We develop a kin‐selection model to investigate the interests of different genes involved in sexual and intragenomic conflict, and we show that consideration of these conflicting interests yields novel predictions concerning parent‐of‐origin specific patterns of gene expression and the detrimental effects of different classes of mutation and epimutation at loci underpinning sexually selected phenotypes. PMID:27991659

Success of cuckoo catfish brood parasitism reflects coevolutionary history and individual experience of their cichlid hosts

PubMed Central

Polačik, Matej; Smith, Carl; Honza, Marcel; Reichard, Martin

2018-01-01

Obligate brood parasites manipulate other species into raising their offspring. Avian and insect brood parasitic systems demonstrate how interacting species engage in reciprocal coevolutionary arms races through behavioral and morphological adaptations and counteradaptations. Mouthbrooding cichlid fishes are renowned for their remarkable evolutionary radiations and complex behaviors. In Lake Tanganyika, mouthbrooding cichlids are exploited by the only obligate nonavian vertebrate brood parasite, the cuckoo catfish Synodontis multipunctatus. We show that coevolutionary history and individual learning both have a major impact on the success of cuckoo catfish parasitism between coevolved sympatric and evolutionarily naïve allopatric cichlid species. The rate of cuckoo catfish parasitism in coevolved Tanganyikan hosts was 3 to 11 times lower than in evolutionarily naïve cichlids. Moreover, using experimental infections, we demonstrate that parasite egg rejection in sympatric hosts was much higher, leading to seven times greater parasite survival in evolutionarily naïve than sympatric hosts. However, a high rejection frequency of parasitic catfish eggs by coevolved sympatric hosts came at a cost of increased rejection of their own eggs. A significant cost of catfish parasitism was universal, except for coevolved sympatric cichlid species with previous experience of catfish parasitism, demonstrating that learning and individual experience both contribute to a successful host response. PMID:29732407

Coevolution in host-parasite systems: behavioural strategies of slave-making ants and their hosts.

PubMed Central

Foitzik, S.; DeHeer, C. J.; Hunjan, D. N.; Herbers, J. M.

2001-01-01

Recently, avian brood parasites and their hosts have emerged as model systems for the study of host-parasite coevolution. However, empirical studies of the highly analogous social parasites, which use the workers of another eusocial species to raise their own young, have never explicitly examined the dynamics of these systems from a coevolutionary perspective. Here, we demonstrate interpopulational variation in behavioural interactions between a socially parasitic slave-maker ant and its host that is consistent with the expectations of host-parasite coevolution. Parasite pressure, as inferred by the size, abundance and raiding frequency of Protomognathus americanus colonies, was highest in a New York population of the host Leptothorax longispinosus and lowest in a West Virginia population. As host-parasite coevolutionary theory would predict, we found that the slave-makers and the hosts from New York were more effective at raiding and defending against raiders, respectively, than were conspecifics from the West Virginia population. Some of these variations in efficacy were brought about by apparently simple shifts in behaviour. These results demonstrate that defence mechanisms against social parasites can evolve, and they give the first indications of the existence of a coevolutionary arms race between a social parasite and its host. PMID:11375101

Co-evolutionary interactions between host resistance and pathogen avirulence genes in rice-Magnaporthe oryzae pathosystem.

PubMed

Singh, Pankaj Kumar; Ray, Soham; Thakur, Shallu; Rathour, Rajeev; Sharma, Vinay; Sharma, Tilak Raj

2018-06-01

Rice and Magnaporthe oryzae constitutes an ideal pathosystem for studying host-pathogen interaction in cereals crops. There are two alternative hypotheses, viz. Arms race and Trench warfare, which explain the co-evolutionary dynamics of hosts and pathogens which are under continuous confrontation. Arms race proposes that both R- and Avr- genes of host and pathogen, respectively, undergo positive selection. Alternatively, trench warfare suggests that either R- or Avr- gene in the pathosystem is under balanced selection intending to stabilize the genetic advantage gained over the opposition. Here, we made an attempt to test the above-stated hypotheses in rice-M. oryzae pathosystem at loci of three R-Avr gene pairs, Piz-t-AvrPiz-t, Pi54-AvrPi54 and Pita-AvrPita using allele mining approach. Allele mining is an efficient way to capture allelic variants existing in the population and to study the selective forces imposed on the variants during evolution. Results of nucleotide diversity, neutrality statistics and phylogenetic analyses reveal that Piz-t, Pi54 and AvrPita are diversified and under positive selection at their corresponding loci, while their counterparts, AvrPiz-t, AvrPi54 and Pita are conserved and under balancing selection, in nature. These results imply that rice-M. oryzae populations are engaged in a trench warfare at least at the three R/Avr loci studied. It is a maiden attempt to study the co-evolution of three R-Avr gene pairs in this pathosystem. Knowledge gained from this study will help in understanding the evolutionary dynamics of host-pathogen interaction in a better way and will also aid in developing new durable blast resistant rice varieties in future. Copyright © 2018 Elsevier Inc. All rights reserved.

Brood parasitism selects for no defence in a cuckoo host.

PubMed

Krüger, Oliver

2011-09-22

In coevolutionary arms races, like between cuckoos and their hosts, it is easy to understand why the host is under selection favouring anti-parasitism behaviour, such as egg rejection, which can lead to parasites evolving remarkable adaptations to 'trick' their host, such as mimetic eggs. But what about cases where the cuckoo egg is not mimetic and where the host does not act against it? Classically, such apparently non-adaptive behaviour is put down to evolutionary lag: given enough time, egg mimicry and parasite avoidance strategies will evolve. An alternative is that absence of egg mimicry and of anti-parasite behaviour is stable. Such stability is at first sight highly paradoxical. I show, using both field and experimental data to parametrize a simulation model, that the absence of defence behaviour by Cape bulbuls (Pycnonotus capensis) against parasitic eggs of the Jacobin cuckoo (Clamator jacobinus) is optimal behaviour. The cuckoo has evolved massive eggs (double the size of bulbul eggs) with thick shells, making it very hard or impossible for the host to eject the cuckoo egg. The host could still avoid brood parasitism by nest desertion. However, higher predation and parasitism risks later in the season makes desertion more costly than accepting the cuckoo egg, a strategy aided by the fact that many cuckoo eggs are incorrectly timed, so do not hatch in time and hence do not reduce host fitness to zero. Selection will therefore prevent the continuation of any coevolutionary arms race. Non-mimetic eggs and absence of defence strategies against cuckoo eggs will be the stable, if at first sight paradoxical, result. This journal is © 2011 The Royal Society

Signatures of co-evolutionary host-pathogen interactions in the genome of the entomopathogenic nematode Steinernema carpocapsae.

PubMed

Flores-Ponce, Mitzi; Vallebueno-Estrada, Miguel; González-Orozco, Eduardo; Ramos-Aboites, Hilda E; García-Chávez, J Noé; Simões, Nelson; Montiel, Rafael

2017-04-26

The entomopathogenic nematode Steinernema carpocapsae has been used worldwide as a biocontrol agent for insect pests, making it an interesting model for understanding parasite-host interactions. Two models propose that these interactions are co-evolutionary processes in such a way that equilibrium is never reached. In one model, known as "arms race", new alleles in relevant genes are fixed in both host and pathogens by directional positive selection, producing recurrent and alternating selective sweeps. In the other model, known as"trench warfare", persistent dynamic fluctuations in allele frequencies are sustained by balancing selection. There are some examples of genes evolving according to both models, however, it is not clear to what extent these interactions might alter genome-level evolutionary patterns and intraspecific diversity. Here we investigate some of these aspects by studying genomic variation in S. carpocapsae and other pathogenic and free-living nematodes from phylogenetic clades IV and V. To look for signatures of an arms-race dynamic, we conducted massive scans to detect directional positive selection in interspecific data. In free-living nematodes, we detected a significantly higher proportion of genes with sites under positive selection than in parasitic nematodes. However, in these genes, we found more enriched Gene Ontology terms in parasites. To detect possible effects of dynamic polymorphisms interactions we looked for signatures of balancing selection in intraspecific genomic data. The observed distribution of Tajima's D values in S. carpocapsae was more skewed to positive values and significantly different from the observed distribution in the free-living Caenorhabditis briggsae. Also, the proportion of significant positive values of Tajima's D was elevated in genes that were differentially expressed after induction with insect tissues as compared to both non-differentially expressed genes and the global scan. Our study provides a first portrait of the effects that lifestyle might have in shaping the patterns of selection at the genomic level. An arms-race between hosts and pathogens seems to be affecting specific genetic functions but not necessarily increasing the number of positively selected genes. Trench warfare dynamics seem to be acting more generally in the genome, likely focusing on genes responding to the interaction, rather than targeting specific genetic functions.

Sexual selection modulates genetic conflicts and patterns of genomic imprinting.

PubMed

Faria, Gonçalo S; Varela, Susana A M; Gardner, Andy

2017-03-01

Recent years have seen a surge of interest in linking the theories of kin selection and sexual selection. In particular, there is a growing appreciation that kin selection, arising through demographic factors such as sex-biased dispersal, may modulate sexual conflicts, including in the context of male-female arms races characterized by coevolutionary cycles. However, evolutionary conflicts of interest need not only occur between individuals, but may also occur within individuals, and sex-specific demography is known to foment such intragenomic conflict in relation to social behavior. Whether and how this logic holds in the context of sexual conflict-and, in particular, in relation to coevolutionary cycles-remains obscure. We develop a kin-selection model to investigate the interests of different genes involved in sexual and intragenomic conflict, and we show that consideration of these conflicting interests yields novel predictions concerning parent-of-origin specific patterns of gene expression and the detrimental effects of different classes of mutation and epimutation at loci underpinning sexually selected phenotypes. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Escalation of a coevolutionary arms race through host rejection of brood parasitic young.

PubMed

Langmore, Naomi E; Hunt, Sarah; Kilner, Rebecca M

2003-03-13

Cuckoo nestlings that evict all other young from the nest soon after hatching impose a high reproductive cost on their hosts. In defence, hosts have coevolved strategies to prevent brood parasitism. Puzzlingly, they do not extend beyond the egg stage. Thus, hosts adept at recognizing foreign eggs remain vulnerable to exploitation by cuckoo nestlings. Here we show that the breach of host egg defences by cuckoos creates a new stage in the coevolutionary cycle. We found that defences used during the egg-laying period by host superb fairy-wrens (Malurus cyaneus) are easily evaded by the Horsfield's bronze-cuckoo (Chrysococcyx basalis), a specialist fairy-wren brood parasite. However, although hosts never deserted their own broods, they later abandoned 40% of nests containing a lone Horsfield's bronze-cuckoo nestling, and 100% of nests with a lone shining bronze-cuckoo nestling (Chrysococcyx lucidus), an occasional fairy-wren brood parasite. Our experiments demonstrate that host discrimination against evictor-cuckoo nestlings is possible, and suggest that it has selected for the evolution of nestling mimicry in bronze-cuckoos.

Cryptic cuckoo eggs hide from competing cuckoos

PubMed Central

Gloag, Ros; Keller, Laurie-Anne; Langmore, Naomi E.

2014-01-01

Interspecific arms races between cuckoos and their hosts have produced remarkable examples of mimicry, with parasite eggs evolving to match host egg appearance and so evade removal by hosts. Certain bronze-cuckoo species, however, lay eggs that are cryptic rather than mimetic. These eggs are coated in a low luminance pigment that camouflages them within the dark interiors of hosts' nests. We investigated whether cuckoo egg crypsis is likely to have arisen from the same coevolutionary processes known to favour egg mimicry. We added high and low luminance-painted eggs to the nests of large-billed gerygones (Gerygone magnirostris), a host of the little bronze-cuckoo (Chalcites minutillus). Gerygones rarely rejected either egg type, and did not reject natural cuckoo eggs. Cuckoos, by contrast, regularly removed an egg from clutches before laying their own and were five times more likely to remove a high luminance model than its low luminance counterpart. Given that we found one-third of all parasitized nests were exploited by multiple cuckoos, our results suggest that competition between cuckoos has been the key selective agent for egg crypsis. In such intraspecific arms races, crypsis may be favoured over mimicry because it can reduce the risk of egg removal to levels below chance. PMID:25122227

A slowly evolving host moves first in symbiotic interactions

NASA Astrophysics Data System (ADS)

Damore, James; Gore, Jeff

2011-03-01

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

A recognition-free mechanism for reliable rejection of brood parasites.

PubMed

Anderson, Michael G; Hauber, Mark E

2007-06-01

Hosts often discard eggs of avian brood parasites, whereas parasitic chicks are typically accepted. This can be explained theoretically by fitness losses associated with adults learning to recognize parasitic young and mistakenly rejecting their own young. A new experimental study confirms that rejection of parasitic chicks, without relying on memory to discriminate between foreign and own young, is a feasible and potentially cost-free mechanism used by reed warblers to reject common cuckoo chicks. By abandoning broods that are in the nest longer than is typical for their own young, parents can reliably reject parasite nestlings and reduce fitness losses owing to having to care for demanding parasitic young. Discrimination without recognition has important implications for the realized trajectories of host-parasite coevolutionary arms races.

Sequence diversity and evolution of antimicrobial peptides in invertebrates.

PubMed

Tassanakajon, Anchalee; Somboonwiwat, Kunlaya; Amparyup, Piti

2015-02-01

Antimicrobial peptides (AMPs) are evolutionarily ancient molecules that act as the key components in the invertebrate innate immunity against invading pathogens. Several AMPs have been identified and characterized in invertebrates, and found to display considerable diversity in their amino acid sequence, structure and biological activity. AMP genes appear to have rapidly evolved, which might have arisen from the co-evolutionary arms race between host and pathogens, and enabled organisms to survive in different microbial environments. Here, the sequence diversity of invertebrate AMPs (defensins, cecropins, crustins and anti-lipopolysaccharide factors) are presented to provide a better understanding of the evolution pattern of these peptides that play a major role in host defense mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Intraspecific variation in a generalist herbivore accounts for differential induction and impact of host plant defences

PubMed Central

Kant, Merijn R; Sabelis, Maurice W; Haring, Michel A; Schuurink, Robert C

2007-01-01

Plants and herbivores are thought to be engaged in a coevolutionary arms race: rising frequencies of plants with anti-herbivore defences exert pressure on herbivores to resist or circumvent these defences and vice versa. Owing to its frequency-dependent character, the arms race hypothesis predicts that herbivores exhibit genetic variation for traits that determine how they deal with the defences of a given host plant phenotype. Here, we show the existence of distinct variation within a single herbivore species, the spider mite Tetranychus urticae, in traits that lead to resistance or susceptibility to jasmonate (JA)-dependent defences of a host plant but also in traits responsible for induction or repression of JA defences. We characterized three distinct lines of T. urticae that differentially induced JA-related defence genes and metabolites while feeding on tomato plants (Solanum lycopersicum). These lines were also differently affected by induced JA defences. The first line, which induced JA-dependent tomato defences, was susceptible to those defences; the second line also induced JA defences but was resistant to them; and the third, although susceptible to JA defences, repressed induction. We hypothesize that such intraspecific variation is common among herbivores living in environments with a diversity of plants that impose diverse selection pressure. PMID:18055390

The coevolutionary dynamics of obligate ant social parasite systems--between prudence and antagonism.

PubMed

Brandt, Miriam; Foitzik, Susanne; Fischer-Blass, Birgit; Heinze, Jürgen

2005-05-01

In this synthesis we apply coevolutionary models to the interactions between socially parasitic ants and their hosts. Obligate social parasite systems are ideal models for coevolution, because the close phylogenetic relationship between these parasites and their hosts results in similar evolutionary potentials, thus making mutual adaptations in a stepwise fashion especially likely to occur. The evolutionary dynamics of host-parasite interactions are influenced by a number of parameters, for example the parasite's transmission mode and rate, the genetic structure of host and parasite populations, the antagonists' migration rates, and the degree of mutual specialisation. For the three types of obligate ant social parasites, queen-tolerant and queen-intolerant inquilines and slavemakers, several of these parameters, and thus the evolutionary trajectory, are likely to differ. Because of the fundamental differences in lifestyle between these social parasite systems, coevolution should further select for different traits in the parasites and their hosts. Queen-tolerant inquilines are true parasites that exert a low selection pressure on their host, because of their rarity and the fact that they do not conduct slave raids to replenish their labour force. Due to their high degree of specialisation and the potential for vertical transmission, coevolutionary theory would predict interactions between these workerless parasites and their hosts to become even more benign over time. Queen-intolerant inquilines that kill the host queen during colony take-over are best described as parasitoids, and their reproductive success is limited by the existing worker force of the invaded host nest. These parasites should therefore evolve strategies to best exploit this fixed resource. Slavemaking ants, by contrast, act as parasites only during colony foundation, while their frequent slave raids follow a predator prey dynamic. They often exploit a number of host species at a given site, and theory predicts that their associations are best described in terms of a highly antagonistic coevolutionary arms race.

Coevolution of Cyanogenic Bamboos and Bamboo Lemurs on Madagascar

PubMed Central

Ballhorn, Daniel J.; Rakotoarivelo, Fanny Patrika; Kautz, Stefanie

2016-01-01

Feeding strategies of specialist herbivores often originate from the coevolutionary arms race of plant defenses and counter-adaptations of herbivores. The interaction between bamboo lemurs and cyanogenic bamboos on Madagascar represents a unique system to study diffuse coevolutionary processes between mammalian herbivores and plant defenses. Bamboo lemurs have different degrees of dietary specialization while bamboos show different levels of chemical defense. In this study, we found variation in cyanogenic potential (HCNp) and nutritive characteristics among five sympatric bamboo species in the Ranomafana area, southeastern Madagascar. The HCNp ranged from 209±72 μmol cyanide*g-1 dwt in Cathariostachys madagascariensis to no cyanide in Bambusa madagascariensis. Among three sympatric bamboo lemur species, the greater bamboo lemur (Prolemur simus) has the narrowest food range as it almost exclusively feeds on the highly cyanogenic C. madagascariensis. Our data suggest that high HCNp is the derived state in bamboos. The ancestral state of lemurs is most likely "generalist" while the ancestral state of bamboo lemurs was determined as equivocal. Nevertheless, as recent bamboo lemurs comprise several "facultative specialists" and only one "obligate specialist" adaptive radiation due to increased flexibility is likely. We propose that escaping a strict food plant specialization enabled facultative specialist bamboo lemurs to inhabit diverse geographical areas. PMID:27532127

New World feline APOBEC3 potently controls inter-genus lentiviral transmission.

PubMed

Konno, Yoriyuki; Nagaoka, Shumpei; Kimura, Izumi; Yamamoto, Keisuke; Kagawa, Yumiko; Kumata, Ryuichi; Aso, Hirofumi; Ueda, Mahoko Takahashi; Nakagawa, So; Kobayashi, Tomoko; Koyanagi, Yoshio; Sato, Kei

2018-04-10

The apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3; A3) gene family appears only in mammalian genomes. Some A3 proteins can be incorporated into progeny virions and inhibit lentiviral replication. In turn, the lentiviral viral infectivity factor (Vif) counteracts the A3-mediated antiviral effect by degrading A3 proteins. Recent investigations have suggested that lentiviral vif genes evolved to combat mammalian APOBEC3 proteins, and have further proposed that the Vif-A3 interaction may help determine the co-evolutionary history of cross-species lentiviral transmission in mammals. Here we address the co-evolutionary relationship between two New World felids, the puma (Puma concolor) and the bobcat (Lynx rufus), and their lentiviruses, which are designated puma lentiviruses (PLVs). We demonstrate that PLV-A Vif counteracts the antiviral action of APOBEC3Z3 (A3Z3) of both puma and bobcat, whereas PLV-B Vif counteracts only puma A3Z3. The species specificity of PLV-B Vif is irrespective of the phylogenic relationships of feline species in the genera Puma, Lynx and Acinonyx. We reveal that the amino acid at position 178 in the puma and bobcat A3Z3 is exposed on the protein surface and determines the sensitivity to PLV-B Vif-mediated degradation. Moreover, although both the puma and bobcat A3Z3 genes are polymorphic, their sensitivity/resistance to PLV Vif-mediated degradation is conserved. To the best of our knowledge, this is the first study suggesting that the host A3 protein potently controls inter-genus lentiviral transmission. Our findings provide the first evidence suggesting that the co-evolutionary arms race between lentiviruses and mammals has occurred in the New World.

Avian vision and the evolution of egg color mimicry in the common cuckoo.

PubMed

Stoddard, Mary Caswell; Stevens, Martin

2011-07-01

Coevolutionary arms races are a potent force in evolution, and brood parasite-host dynamics provide classical examples. Different host-races of the common cuckoo, Cuculus canorus, lay eggs in the nests of other species, leaving all parental care to hosts. Cuckoo eggs often (but not always) appear to match remarkably the color and pattern of host eggs, thus reducing detection by hosts. However, most studies of egg mimicry focus on human assessments or reflectance spectra, which fail to account for avian vision. Here, we use discrimination and tetrachromatic color space modeling of bird vision to quantify egg background and spot color mimicry in the common cuckoo and 11 of its principal hosts, and we relate this to egg rejection by different hosts. Egg background color and luminance are strongly mimicked by most cuckoo host-races, and mimicry is better when hosts show strong rejection. We introduce a novel measure of color mimicry-"color overlap"-and show that cuckoo and host background colors increasingly overlap in avian color space as hosts exhibit stronger rejection. Finally, cuckoos with better background color mimicry also have better pattern mimicry. Our findings reveal new information about egg mimicry that would be impossible to derive by the human eye. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Assessing the potential for an ongoing arms race within and between the sexes: selection and heritable variation.

PubMed

Friberg, Urban; Lew, Timothy A; Byrne, Phillip G; Rice, William R

2005-07-01

In promiscuous species, sexual selection generates two opposing male traits: offense (acquiring new mates and supplanting stored sperm) and defense (enforcing fidelity on one's mates and preventing sperm displacement when this fails). Coevolution between these traits requires both additive genetic variation and associated natural selection. Previous work with Drosophila melanogaster found autosomal genetic variation for these traits among inbred lines from a mixture of populations, but only nonheritable genetic variation was found within a single outbred population. These results do not support ongoing antagonistic coevolution between offense and defense, nor between either of these male traits and female reproductive characters. Here we use a new method (hemiclonal analysis) to study genomewide genetic variation in a large outbred laboratory population of D. melanogaster. Hemiclonal analysis estimates the additive genetic variation among random, genomewide haplotypes taken from a large, outbred, locally adapted laboratory population and determines the direction of the selection gradient on this variation. In contrast to earlier studies, we found low but biologically significant heritable variation for defensive and offensive offspring production as well as all their components (P1, fidelity, P2, and remating). Genetic correlations between these traits were substantially different from those reported for inbred lines. A positive genetic correlation was found between defense and offense, demonstrating that some shared genes influence both traits. In addition to this common variation, evidence for unique genetic variation for each trait was also found, supporting an ongoing coevolutionary arms race between defense and offense. Reproductive conflict between males can strongly influence female fitness. Correspondingly, we found genetic variation in both defense and offense that affected female fitness. No evidence was found for intersexual conflict in the context of male defense, but we found substantial intersexual conflict in the context of male offensive sperm competitive ability. These results indicate that conflict between competing males also promotes an associated arms race between the sexes.

Co-evolution in a landrace meta-population: two closely related pathogens interacting with the same host can lead to different adaptive outcomes.

PubMed

Rau, Domenico; Rodriguez, Monica; Leonarda Murgia, Maria; Balmas, Virgilio; Bitocchi, Elena; Bellucci, Elisa; Nanni, Laura; Attene, Giovanna; Papa, Roberto

2015-08-07

We examined the local adaptation patterns in a system comprising several interconnected heterogeneous plant populations from which populations of two phylogenetically closely related pathogens were also sampled. The host is Hordeum vulgare (cultivated barley); the pathogens are Pyrenophora teres f. teres (net form) and Pyrenophora teres f. maculata (spot form), the causal agents of barley net blotch. We integrated two approaches, the comparison between the population structures of the host and the pathogens, and a cross-inoculation test. We demonstrated that two closely related pathogens with very similar niche specialisation and life-styles can give rise to different co-evolutionary outcomes on the same host. Indeed, we detected local adaptation for the net form of the pathogen but not for the spot form. We also provided evidence that an a-priori well-known resistance quantitative-trait-locus on barley chromosome 6H is involved in the co-evolutionary 'arms race' between the plant and the net-form pathogen. Moreover, data suggested latitudinal clines of host resistance and that different ecological conditions can result in differential selective pressures at different sites. Our data are of interest for on-farm conservation of plant genetic resources, as also in establishing efficient breeding programs and strategies for deployment of resistance genes of P. teres.

RNA interference: a new strategy in the evolutionary arms race between human control strategies and insect pests.

PubMed

Machado, Vilmar; Rodríguez-García, María Juliana; Sánchez-García, Francisco Javier; Galan, Jose

2014-01-01

The relationship between humans and the insect pests of cultivated plants may be considered to be an indirect coevolutionary process, i.e., an arms race. Over time, humans have developed several strategies to minimize the negative impacts of insects on agricultural production. However, insects have made adaptive responses via the evolution of resistance to insecticides, and more recently against Bacillus thuriengiensis. Thus, we need to continuously invest resources in the development of new strategies for crop protection. Recent advances in genomics have demonstrated the possibility of a new weapon or strategy in this war, i.e., gene silencing, which involves blocking the expression of specific genes via mRNA inactivation. In the last decade, several studies have demonstrated the effectiveness of this strategy in the control of different species of insects. However, several technical difficulties need to be overcome to transform this potential into reality, such as the selection of target genes, the concentration of dsRNA, the nucleotide sequence of the dsRNA, the length of dsRNA, persistence in the insect body, and the life stage of the target species where gene silencing is most efficient. This study analyzes several aspects related to the use of gene silencing in pest control and it includes an overview of the inactivation process, as well as the problems that need to be resolved to transform gene silencing into an effective pest control method.

Visual mimicry of host nestlings by cuckoos

PubMed Central

Langmore, Naomi E.; Stevens, Martin; Maurer, Golo; Heinsohn, Robert; Hall, Michelle L.; Peters, Anne; Kilner, Rebecca M.

2011-01-01

Coevolution between antagonistic species has produced instances of exquisite mimicry. Among brood-parasitic cuckoos, host defences have driven the evolution of mimetic eggs, but the evolutionary arms race was believed to be constrained from progressing to the chick stage, with cuckoo nestlings generally looking unlike host young. However, recent studies on bronze-cuckoos have confounded theoretical expectations by demonstrating cuckoo nestling rejection by hosts. Coevolutionary theory predicts reciprocal selection for visual mimicry of host young by cuckoos, although this has not been demonstrated previously. Here we show that, in the eyes of hosts, nestlings of three bronze-cuckoo species are striking visual mimics of the young of their morphologically diverse hosts, providing the first evidence that coevolution can select for visual mimicry of hosts in cuckoo chicks. Bronze-cuckoos resemble their own hosts more closely than other host species, but the accuracy of mimicry varies according to the diversity of hosts they exploit. PMID:21227972

C. elegans avoids toxin-producing Streptomyces using a seven transmembrane domain chemosensory receptor

PubMed Central

Tran, Alan; Tang, Angelina; O'Loughlin, Colleen T; Jimenez, Vanessa; Pyle, Jacqueline; Tsujimoto, Bryan; Wellbrook, Christopher; Vargas, Christopher; Duong, Alex; Ali, Nebat; Matthews, Sarah Y; Levinson, Samantha; Woldemariam, Sarah; Khuri, Sami; Bremer, Martina; Eggers, Daryl K; L'Etoile, Noelle

2017-01-01

Predators and prey co-evolve, each maximizing their own fitness, but the effects of predator–prey interactions on cellular and molecular machinery are poorly understood. Here, we study this process using the predator Caenorhabditis elegans and the bacterial prey Streptomyces, which have evolved a powerful defense: the production of nematicides. We demonstrate that upon exposure to Streptomyces at their head or tail, nematodes display an escape response that is mediated by bacterially produced cues. Avoidance requires a predicted G-protein-coupled receptor, SRB-6, which is expressed in five types of amphid and phasmid chemosensory neurons. We establish that species of Streptomyces secrete dodecanoic acid, which is sensed by SRB-6. This behavioral adaptation represents an important strategy for the nematode, which utilizes specialized sensory organs and a chemoreceptor that is tuned to recognize the bacteria. These findings provide a window into the molecules and organs used in the coevolutionary arms race between predator and potential prey. PMID:28873053

Raiders from the sky: slavemaker founding queens select for aggressive host colonies

PubMed Central

Pamminger, Tobias; Modlmeier, Andreas P.; Suette, Stefan; Pennings, Pleuni S.; Foitzik, Susanne

2012-01-01

Reciprocal selection pressures in host–parasite systems drive coevolutionary arms races that lead to advanced adaptations in both opponents. In the interactions between social parasites and their hosts, aggression is one of the major behavioural traits under selection. In a field manipulation, we aimed to disentangle the impact of slavemaking ants and nest density on aggression of Temnothorax longispinosus ants. An early slavemaker mating flight provided us with the unique opportunity to study the influence of host aggression and demography on founding decisions and success. We discovered that parasite queens avoided colony foundation in parasitized areas and were able to capture more brood from less aggressive host colonies. Host colony aggression remained consistent over the two-month experiment, but did not respond to our manipulation. However, as one-fifth of all host colonies were successfully invaded by parasite queens, slavemaker nest foundation acts as a strong selection event selecting for high aggression in host colonies. PMID:22809720

Natural selection drives chemical resistance of Datura stramonium

PubMed Central

Miranda-Pérez, Adán; Castillo, Guillermo; Hernández-Cumplido, Johnattan; Valverde, Pedro L.; Borbolla, María; Cruz, Laura L.; Tapia-López, Rosalinda; Fornoni, Juan; Flores-Ortiz, César M.

2016-01-01

Plant resistance to herbivores involves physical and chemical plant traits that prevent or diminish damage by herbivores, and hence may promote coevolutionary arm-races between interacting species. Although Datura stramonium’s concentration of tropane alkaloids is under selection by leaf beetles, it is not known whether chemical defense reduces seed predation by the specialist weevil, Trichobaris soror, and if it is evolving by natural selection. We measured infestation by T. soror as well as the concentration of the plants’ two main tropane alkaloids in 278 D. stramonium plants belonging to 31 populations in central Mexico. We assessed whether the seed predator exerted preferences on the levels of both alkaloids and whether they affect plant fitness. Results show great variation across populations in the concentration of scopolamine and atropine in both leaves and seeds of plants of D. stramonium, as well as in the intensity of infestation and the proportion of infested fruits by T. soror. The concentration of scopolamine in seeds and leaves are negatively associated across populations. We found that scopolamine concentration increases plant fitness. Our major finding was the detection of a positive relationship between the population average concentrations of scopolamine with the selection differentials of scopolamine. Such spatial variation in the direction and intensity of selection on scopolamine may represent a coevolutionary selective mosaic. Our results support the view that variation in the concentration of scopolamine among-populations of D. stramonium in central Mexico is being driven, in part, by selection exerted by T. soror, pointing an adaptive role of tropane alkaloids in this plant species. PMID:27114866

The escalatory Red Queen: Population extinction and replacement following arms race dynamics in poplar rust.

PubMed

Persoons, Antoine; Hayden, Katherine J; Fabre, Bénédicte; Frey, Pascal; De Mita, Stéphane; Tellier, Aurélien; Halkett, Fabien

2017-04-01

Host-parasite systems provide convincing examples of Red Queen co-evolutionary dynamics. Yet, a key process underscored in Van Valen's theory - that arms race dynamics can result in extinction - has never been documented. One reason for this may be that most sampling designs lack the breadth needed to illuminate the rapid pace of adaptation by pathogen populations. In this study, we used a 25-year temporal sampling to decipher the demographic history of a plant pathogen: the poplar rust fungus, Melampsora larici-populina. A major adaptive event occurred in 1994 with the breakdown of R7 resistance carried by several poplar cultivars widely planted in Western Europe since 1982. The corresponding virulence rapidly spread in M. larici-populina populations and nearly reached fixation in northern France, even on susceptible hosts. Using both temporal records of virulence profiles and temporal population genetic data, our analyses revealed that (i) R7 resistance breakdown resulted in the emergence of a unique and homogeneous genetic group, the so-called cultivated population, which predominated in northern France for about 20 years, (ii) selection for Vir7 individuals brought with it multiple other virulence types via hitchhiking, resulting in an overall increase in the population-wide number of virulence types and (iii) - above all - the emergence of the cultivated population superseded the initial population which predominated at the same place before R7 resistance breakdown. Our temporal analysis illustrates how antagonistic co-evolution can lead to population extinction and replacement, hence providing direct evidence for the escalation process which is at the core of Red Queen dynamics. © 2016 John Wiley & Sons Ltd.

Arms races between and within species.

PubMed

Dawkins, R; Krebs, J R

1979-09-21

An adaptation in one lineage (e.g. predators) may change the selection pressure on another lineage (e.g. prey), giving rise to a counter-adaptation. If this occurs reciprocally, an unstable runaway escalation or 'arms race' may result. We discuss various factors which might give one side an advantage in an arms race. For example, a lineage under strong selection may out-evolve a weakly selected one (' the life-dinner principle'). We then classify arms races in two independent ways. They may be symmetric or asymmetric, and they may be interspecific or intraspecific. Our example of an asymmetric interspecific arms race is that between brood parasites and their hosts. The arms race concept may help to reduce the mystery of why cuckoo hosts are so good at detecting cuckoo eggs, but so bad at detecting cuckoo nestlings. The evolutionary contest between queen and worker ants over relative parental investment is a good example of an intraspecific asymmetric arms race. Such cases raise special problems because the participants share the same gene pool. Interspecific symmetric arms races are unlikely to be important, because competitors tend to diverge rather than escalate competitive adaptations. Intraspecific symmetric arms races, exemplified by adaptations for male-male competition, may underlie Cope's Rule and even the extinction of lineages. Finally we consider ways in which arms races can end. One lineage may drive the other to extinction; one may reach an optimum, thereby preventing the other from doing so; a particularly interesting possibility, exemplified by flower-bee coevolution, is that both sides may reach a mutual local optimum; lastly, arms races may have no stable and but may cycle continuously. We do not wish necessarily to suggest that all, or even most, evolutionary change results from arms races, but we do suggest that the arms race concept may help to resolve three long-standing questions in evolutionary theory.

The Compatibility Between Biomphalaria glabrata Snails and Schistosoma mansoni: An Increasingly Complex Puzzle.

PubMed

Mitta, G; Gourbal, B; Grunau, C; Knight, M; Bridger, J M; Théron, A

2017-01-01

This review reexamines the results obtained in recent decades regarding the compatibility polymorphism between the snail, Biomphalaria glabrata, and the pathogen, Schistosoma mansoni, which is one of the agents responsible for human schistosomiasis. Some results point to the snail's resistance as explaining the incompatibility, while others support a "matching hypothesis" between the snail's immune receptors and the schistosome's antigens. We propose here that the two hypotheses are not exclusive, and that the compatible/incompatible status of a particular host/parasite couple probably reflects the balance of multiple molecular determinants that support one hypothesis or the other. Because these genes are involved in a coevolutionary arms race, we also propose that the underlying mechanisms can vary. Finally, some recent results show that environmental factors could influence compatibility. Together, these results make the compatibility between B. glabrata and S. mansoni an increasingly complex puzzle. We need to develop more integrative approaches in order to find targets that could potentially be manipulated to control the transmission of schistosomiasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ants and antlions: The impact of ecology, coevolution and learning on an insect predator-prey relationship.

PubMed

Hollis, Karen L

2017-06-01

A behavioural ecological approach to the relationship between pit-digging larval antlions and their common prey, ants, provides yet another example of how the specific ecological niche that species inhabit imposes selection pressures leading to unique behavioural adaptations. Antlions rely on multiple strategies to capture prey with a minimal expenditure of energy and extraordinary efficiency while ants employ several different strategies for avoiding capture, including rescue of trapped nestmates. Importantly, both ants and antlions rely heavily on their capacity for learning, a tool that sometimes is overlooked in predator-prey relationships, leading to the implicit assumption that behavioural adaptations are the result of fixed, hard-wired responses. Nonetheless, like hard-wired responses, learned behaviour, too, is uniquely adapted to the ecological niche, a reminder that the expression of associative learning is species-specific. Beyond the study of ants and antlions, per se, this particular predator-prey relationship reveals the important role that the capacity to learn plays in coevolutionary arms races. Copyright © 2016 Elsevier B.V. All rights reserved.

Vertically transmitted viral endosymbionts of insects: do sigma viruses walk alone?

PubMed

Longdon, Ben; Jiggins, Francis M

2012-10-07

Insects are host to a wide range of vertically transmitted bacterial endosymbionts, but we know relatively little about their viral counterparts. Here, we discuss the vertically transmitted viral endosymbionts of insects, firstly examining the diversity of this group, and then focusing on the well-studied sigma viruses that infect dipterans. Despite limited sampling, evidence suggests that vertically transmitted viruses may be common in insects. Unlike bacteria, viruses can be transmitted through sperm and eggs, a trait that allows them to rapidly spread through host populations even when infection is costly to the host. Work on Drosophila melanogaster has shown that sigma viruses and their hosts are engaged in a coevolutionary arms race, in which the spread of resistance genes in the host population is followed by the spread of viral genotypes that can overcome host resistance. In the long-term, associations between sigma viruses and their hosts are unstable, and the viruses persist by occasionally switching to new host species. It therefore seems likely that viral endosymbionts have major impacts on the evolution and ecology of insects.

Vertically transmitted viral endosymbionts of insects: do sigma viruses walk alone?

PubMed Central

Longdon, Ben; Jiggins, Francis M.

2012-01-01

Insects are host to a wide range of vertically transmitted bacterial endosymbionts, but we know relatively little about their viral counterparts. Here, we discuss the vertically transmitted viral endosymbionts of insects, firstly examining the diversity of this group, and then focusing on the well-studied sigma viruses that infect dipterans. Despite limited sampling, evidence suggests that vertically transmitted viruses may be common in insects. Unlike bacteria, viruses can be transmitted through sperm and eggs, a trait that allows them to rapidly spread through host populations even when infection is costly to the host. Work on Drosophila melanogaster has shown that sigma viruses and their hosts are engaged in a coevolutionary arms race, in which the spread of resistance genes in the host population is followed by the spread of viral genotypes that can overcome host resistance. In the long-term, associations between sigma viruses and their hosts are unstable, and the viruses persist by occasionally switching to new host species. It therefore seems likely that viral endosymbionts have major impacts on the evolution and ecology of insects. PMID:22859592

Plant Insecticidal Toxins in Ecological Networks

PubMed Central

Ibanez, Sébastien; Gallet, Christiane; Després, Laurence

2012-01-01

Plant secondary metabolites play a key role in plant-insect interactions, whether constitutive or induced, C- or N-based. Anti-herbivore defences against insects can act as repellents, deterrents, growth inhibitors or cause direct mortality. In turn, insects have evolved a variety of strategies to act against plant toxins, e.g., avoidance, excretion, sequestration and degradation of the toxin, eventually leading to a co-evolutionary arms race between insects and plants and to co-diversification. Anti-herbivore defences also negatively impact mutualistic partners, possibly leading to an ecological cost of toxin production. However, in other cases toxins can also be used by plants involved in mutualistic interactions to exclude inadequate partners and to modify the cost/benefit ratio of mutualism to their advantage. When considering the whole community, toxins have an effect at many trophic levels. Aposematic insects sequester toxins to defend themselves against predators. Depending on the ecological context, toxins can either increase insects’ vulnerability to parasitoids and entomopathogens or protect them, eventually leading to self-medication. We conclude that studying the community-level impacts of plant toxins can provide new insights into the synthesis between community and evolutionary ecology. PMID:22606374

Human sexual conflict from molecules to culture.

PubMed

Gorelik, Gregory; Shackelford, Todd K

2011-12-15

Coevolutionary arms races between males and females have equipped both sexes with mutually manipulative and defensive adaptations. These adaptations function to benefit individual reproductive interests at the cost of the reproductive interests of opposite-sex mates, and arise from evolutionary dynamics such as parental investment (unequal reproductive costs between the sexes) and sexual selection (unequal access to opposite-sex mates). Individuals use these adaptations to hijack others' reproductive systems, psychological states, and behaviors--essentially using other individuals as extended phenotypes of themselves. Such extended phenotypic manipulation of sexual rivals and opposite-sex mates is enacted by humans with the aid of hormones, pheromones, neurotransmitters, emotions, language, mind-altering substances, social institutions, technologies, and ideologies. Furthermore, sexual conflict may be experienced at an individual level when maternal genes and paternal genes are in conflict within an organism. Sexual conflict may be physically and emotionally destructive, but may also be exciting and constructive for relationships. By extending the biological concept of sexual conflict into social and cultural domains, scholars may successfully bridge many of the interdisciplinary gaps that separate the sciences from the humanities.

Teaching about Reversing the Arms Race.

ERIC Educational Resources Information Center

Melman, Seymour

1982-01-01

The scarcity of college courses dealing with disarmament is noted, and educators are urged to address the question of arms limitation. Military and economic factors which limit the ability of the United States to continue the arms race are listed, and plans for reversing the arms race are discussed. (PP)

Teaching on Science, Technology and the Nuclear Arms Race.

ERIC Educational Resources Information Center

Schroeer, Dietrich

1983-01-01

Describes a course focusing on science, technology, and the nuclear arms race. Two sample homework exercises and course topics are provided. Topics, with lists of questions that might be addressed, focus on nuclear weapons, alternatives to deterrence, and arms control. Approaches to teaching about the nuclear arms race are also provided. (JN)

Evolution of extortion in Iterated Prisoner's Dilemma games.

PubMed

Hilbe, Christian; Nowak, Martin A; Sigmund, Karl

2013-04-23

Iterated games are a fundamental component of economic and evolutionary game theory. They describe situations where two players interact repeatedly and have the ability to use conditional strategies that depend on the outcome of previous interactions, thus allowing for reciprocation. Recently, a new class of strategies has been proposed, so-called "zero-determinant" strategies. These strategies enforce a fixed linear relationship between one's own payoff and that of the other player. A subset of those strategies allows "extortioners" to ensure that any increase in one player's own payoff exceeds that of the other player by a fixed percentage. Here, we analyze the evolutionary performance of this new class of strategies. We show that in reasonably large populations, they can act as catalysts for the evolution of cooperation, similar to tit-for-tat, but that they are not the stable outcome of natural selection. In very small populations, however, extortioners hold their ground. Extortion strategies do particularly well in coevolutionary arms races between two distinct populations. Significantly, they benefit the population that evolves at the slower rate, an example of the so-called "Red King" effect. This may affect the evolution of interactions between host species and their endosymbionts.

Collective defence portfolios of ant hosts shift with social parasite pressure

PubMed Central

Jongepier, Evelien; Kleeberg, Isabelle; Job, Sylwester; Foitzik, Susanne

2014-01-01

Host defences become increasingly costly as parasites breach successive lines of defence. Because selection favours hosts that successfully resist parasitism at the lowest possible cost, escalating coevolutionary arms races are likely to drive host defence portfolios towards ever more expensive strategies. We investigated the interplay between host defence portfolios and social parasite pressure by comparing 17 populations of two Temnothorax ant species. When successful, collective aggression not only prevents parasitation but also spares host colonies the cost of searching for and moving to a new nest site. However, once parasites breach the host's nest defence, host colonies should resort to flight as the more beneficial resistance strategy. We show that under low parasite pressure, host colonies more likely responded to an intruding Protomognathus americanus slavemaker with collective aggression, which prevented the slavemaker from escaping and potentially recruiting nest-mates. However, as parasite pressure increased, ant colonies of both host species became more likely to flee rather than to fight. We conclude that host defence portfolios shift consistently with social parasite pressure, which is in accordance with the degeneration of frontline defences and the evolution of subsequent anti-parasite strategies often invoked in hosts of brood parasites. PMID:25100690

Chemical disguise as particular caste of host ants in the ant inquiline parasite Niphanda fusca (Lepidoptera: Lycaenidae)

PubMed Central

Hojo, Masaru K.; Wada-Katsumata, Ayako; Akino, Toshiharu; Yamaguchi, Susumu; Ozaki, Mamiko; Yamaoka, Ryohei

2008-01-01

The exploitation of parental care is common in avian and insect ‘cuckoos’ and these species engage in a coevolutionary arms race. Caterpillars of the lycaenid butterfly Niphanda fusca develop as parasites inside the nests of host ants (Camponotus japonicus) where they grow by feeding on the worker trophallaxis. We hypothesized that N. fusca caterpillars chemically mimic host larvae, or some particular castes of the host ant, so that the caterpillars are accepted and cared for by the host workers. Behaviourally, it was observed that the host workers enthusiastically tended glass dummies coated with the cuticular chemicals of larvae or males and those of N. fusca caterpillars living together. Cuticular chemical analyses revealed that N. fusca caterpillars grown in a host ant nest acquired a colony-specific blend of cuticular hydrocarbons (CHCs). Furthermore, the CHC profiles of the N. fusca caterpillars were particularly close to those of the males rather than those of the host larvae and the others. We suggest that N. fusca caterpillars exploit worker care by matching their cuticular profile to that of the host males, since the males are fed by trophallaxis with workers in their natal nests for approximately ten months. PMID:18842547

Evolution of extortion in Iterated Prisoner’s Dilemma games

PubMed Central

Hilbe, Christian; Nowak, Martin A.; Sigmund, Karl

2013-01-01

Iterated games are a fundamental component of economic and evolutionary game theory. They describe situations where two players interact repeatedly and have the ability to use conditional strategies that depend on the outcome of previous interactions, thus allowing for reciprocation. Recently, a new class of strategies has been proposed, so-called “zero-determinant” strategies. These strategies enforce a fixed linear relationship between one’s own payoff and that of the other player. A subset of those strategies allows “extortioners” to ensure that any increase in one player’s own payoff exceeds that of the other player by a fixed percentage. Here, we analyze the evolutionary performance of this new class of strategies. We show that in reasonably large populations, they can act as catalysts for the evolution of cooperation, similar to tit-for-tat, but that they are not the stable outcome of natural selection. In very small populations, however, extortioners hold their ground. Extortion strategies do particularly well in coevolutionary arms races between two distinct populations. Significantly, they benefit the population that evolves at the slower rate, an example of the so-called “Red King” effect. This may affect the evolution of interactions between host species and their endosymbionts. PMID:23572576

Origin and maintenance of chemical diversity in a species-rich tropical tree lineage.

PubMed

Salazar, Diego; Lokvam, John; Mesones, Italo; Vásquez Pilco, Magno; Ayarza Zuñiga, Jacqueline Milagros; de Valpine, Perry; Fine, Paul V A

2018-06-01

Plant secondary metabolites play important ecological and evolutionary roles, most notably in the deterrence of natural enemies. The classical theory explaining the evolution of plant chemical diversity is that new defences arise through a pairwise co-evolutionary arms race between plants and their specialized natural enemies. However, plant species are bombarded by dozens of different herbivore taxa from disparate phylogenetic lineages that span a wide range of feeding strategies and have distinctive physiological constraints that interact differently with particular plant metabolites. How do plant defence chemicals evolve under such multiple and potentially contrasting selective pressures imposed by diverse herbivore communities? To tackle this question, we exhaustively characterized the chemical diversity and insect herbivore fauna from 31 sympatric species of Amazonian Protieae (Burseraceae) trees. Using a combination of phylogenetic, metabolomic and statistical learning tools, we show that secondary metabolites that were associated with repelling herbivores (1) were more frequent across the Protieae phylogeny and (2) were found in average higher abundance than other compounds. Our findings suggest that generalist herbivores can play an important role in shaping plant chemical diversity and support the hypothesis that chemical diversity can also arise from the cumulative outcome of multiple diffuse interactions.

The Arms Race and World Hunger. Facts for Action #4.

ERIC Educational Resources Information Center

Phillips, Jim

Designed for high school global education classes, this document examines ways in which the arms race affects the poor. Military expenditures and foreign economic aid of the developed nations are compared with survival needs of developing nations. Statistics support five premises: the arms race (1) diverts resources from productive activity and…

Secretome Characterization and Correlation Analysis Reveal Putative Pathogenicity Mechanisms and Identify Candidate Avirulence Genes in the Wheat Stripe Rust Fungus Puccinia striiformis f. sp. tritici.

PubMed

Xia, Chongjing; Wang, Meinan; Cornejo, Omar E; Jiwan, Derick A; See, Deven R; Chen, Xianming

2017-01-01

Stripe (yellow) rust, caused by Puccinia striiformis f. sp. tritici ( Pst ), is one of the most destructive diseases of wheat worldwide. Planting resistant cultivars is an effective way to control this disease, but race-specific resistance can be overcome quickly due to the rapid evolving Pst population. Studying the pathogenicity mechanisms is critical for understanding how Pst virulence changes and how to develop wheat cultivars with durable resistance to stripe rust. We re-sequenced 7 Pst isolates and included additional 7 previously sequenced isolates to represent balanced virulence/avirulence profiles for several avirulence loci in seretome analyses. We observed an uneven distribution of heterozygosity among the isolates. Secretome comparison of Pst with other rust fungi identified a large portion of species-specific secreted proteins, suggesting that they may have specific roles when interacting with the wheat host. Thirty-two effectors of Pst were identified from its secretome. We identified candidates for Avr genes corresponding to six Yr genes by correlating polymorphisms for effector genes to the virulence/avirulence profiles of the 14 Pst isolates. The putative AvYr76 was present in the avirulent isolates, but absent in the virulent isolates, suggesting that deleting the coding region of the candidate avirulence gene has produced races virulent to resistance gene Yr76 . We conclude that incorporating avirulence/virulence phenotypes into correlation analysis with variations in genomic structure and secretome, particularly presence/absence polymorphisms of effectors, is an efficient way to identify candidate Avr genes in Pst . The candidate effector genes provide a rich resource for further studies to determine the evolutionary history of Pst populations and the co-evolutionary arms race between Pst and wheat. The Avr candidates identified in this study will lead to cloning avirulence genes in Pst , which will enable us to understand molecular mechanisms underlying Pst -wheat interactions, to determine the effectiveness of resistance genes and further to develop durable resistance to stripe rust.

Guns & Kids: Human Costs of the Arms Race.

ERIC Educational Resources Information Center

Edelman, Marian Wright

1983-01-01

The human costs of the arms race are outlined, including how children die from preventable malnutrition and disease while the world spends $600 billion annually on arms. The author supports attending to the needs of children and the poor through action for peace. (MD)

Coevolution between Hispaniolan crossbills and pine: does more time allow for greater phenotypic escalation at lower latitude?

PubMed

Parchman, Thomas L; Benkman, Craig W; Mezquida, Eduardo T

2007-09-01

Crossbills (Aves: Loxia) and several conifers have coevolved in predator-prey arms races over the last 10,000 years. However, the extent to which coevolutionary arms races have contributed to the adaptive radiation of crossbills or to any other adaptive radiation is largely unknown. Here we extend our previous studies of geographically structured coevolution by considering a crossbill-conifer interaction that has persisted for a much longer time period and involves a conifer with more variable annual seed production. We examined geographic variation in the cone and seed traits of two sister species of pines, Pinus occidentalis and P. cubensis, on the islands of Hispaniola and Cuba, respectively. We also compared the Hispaniolan crossbill (Loxia megaplaga) to its sister taxa the North American white-winged crossbill (Loxia leucoptera leucoptera). The Hispaniolan crossbill is endemic to Hispaniola whereas Cuba lacks crossbills. In addition and in contrast to previous studies, the variation in selection experienced by these pines due to crossbills is not confounded by the occurrence of selection by tree squirrels (Tamiasciurus and Sciurus). As predicted if P. occidentalis has evolved defenses in response to selection exerted by crossbills, cones of P. occidentalis have scales that are 53% thicker than those of P. cubensis. Cones of P. occidentalis, but not P. cubensis, also have well-developed spines, a known defense against vertebrate seed predators. Consistent with patterns of divergence seen in crossbills coevolving locally with other conifers, the Hispaniolan crossbill has evolved a bill that is 25% deeper than the white-winged crossbill. Together with phylogenetic analyses, our results suggest that predator-prey coevolution between Hispaniolan crossbills and P. occidentalis over approximately 600,000 years has caused substantial morphological evolution in both the crossbill and pine. This also indicates that cone crop fluctuations do not prevent crossbills and conifers from coevolving. Furthermore, because the traits at the phenotypic interface of the interaction apparently remain the same over at least several hundred thousand years, divergence as a result of coevolution is greater at lower latitude where crossbill-conifer interactions have been less interrupted by Pleistocene events.

The Geometry of the Arms Race. Applications of Elementary Game Theory to International Relations. Modules and Monographs in Undergraduate Mathematics and Its Applications Project. UMAP Unit 311.

ERIC Educational Resources Information Center

Brams, Steven J.; And Others

This unit views applications of elementary game theory to international relations. It is noted that of all the significant world problems, the nuclear arms race has proved one of the most intractable. The main concern of the module is to investigate a possible solution to the arms race, based on extending the classic two-person game of Prisoner's…

Science and society test VIII: The arms race revisited

NASA Astrophysics Data System (ADS)

Hafemeister, David W.

1983-03-01

Approximate numerical estimates are developed in order to quantify a variety of aspects of the arms race. The results of these calculations are consistent with either direct observations or with more sophisticated calculations. This paper will cover some of the following aspects of the arms race: (1) the electromagnetic pulse (EMP); (2) spy satellites; (3) ICBM accuracy; (4) NAVSTAR global positioning satellites; (5) particle and laser beam weapons; (6) the neutron bomb; and (7) war games.

Macroevolutionary patterns of glucosinolate defense and tests of defense-escalation and resource availability hypotheses.

PubMed

Cacho, N Ivalú; Kliebenstein, Daniel J; Strauss, Sharon Y

2015-11-01

We explored macroevolutionary patterns of plant chemical defense in Streptanthus (Brassicaceae), tested for evolutionary escalation of defense, as predicted by Ehrlich and Raven's plant-herbivore coevolutionary arms-race hypothesis, and tested whether species inhabiting low-resource or harsh environments invest more in defense, as predicted by the resource availability hypothesis (RAH). We conducted phylogenetically explicit analyses using glucosinolate profiles, soil nutrient analyses, and microhabitat bareness estimates across 30 species of Streptanthus inhabiting varied environments and soils. We found weak to moderate phylogenetic signal in glucosinolate classes and no signal in total glucosinolate production; a trend toward evolutionary de-escalation in the numbers and diversity of glucosinolates, accompanied by an evolutionary increase in the proportion of aliphatic glucosinolates; some support for the RAH relative to soil macronutrients, but not relative to serpentine soil use; and that the number of glucosinolates increases with microhabitat bareness, which is associated with increased herbivory and drought. Weak phylogenetic signal in chemical defense has been observed in other plant systems. A more holistic approach incorporating other forms of defense might be necessary to confidently reject escalation of defense. That defense increases with microhabitat bareness supports the hypothesis that habitat bareness is an underappreciated selective force on plants in harsh environments. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

The battle of the sexes over seed size: support for both kinship genomic imprinting and interlocus contest evolution.

PubMed

Willi, Yvonne

2013-06-01

Outcrossing creates a venue for parental conflict. When one sex provides parental care to offspring fertilized by several partners, the nonproviding sex is under selection to maximally exploit the caring sex. The caring sex may counteradapt, and a coevolutionary arms race ensues. Genetic models of this conflict include the kinship theory of genomic imprinting (parent-of-origin-specific expression of maternal-care effectors) and interlocus conflict evolution (interaction between male selfish signals and female abatement). Predictions were tested by measuring the sizes of seeds produced by within-population crosses (diallel design) and between-population crosses in outcrossing and selfing populations of Arabidopsis lyrata. Within-population diallel crosses revealed substantial maternal variance in seed size in most populations. The comparison of between- and within-population crosses showed that seeds were larger when pollen came from another outcrossing population than when pollen came from a selfing or the same population, supporting interlocus contest evolution between male selfish genes and female recognition genes. Evidence for kinship genomic imprinting came from complementary trait means of seed size in reciprocal between-population crosses independent of whether populations were predominantly selfing or outcrossing. Hence, both kinship genomic imprinting and interlocus contest are supported in outcrossing Arabidopsis, whereas only kinship genomic imprinting is important in selfing populations.

Fitness and virulence of a bacterial endoparasite in an environmentally stressed crustacean host.

PubMed

Coors, Anja; De Meester, Luc

2011-01-01

Host-parasite interactions are shaped by the co-evolutionary arms race of parasite virulence, transmission success as well as host resistance and recovery. The virulence and fitness of parasites may depend on host condition, which is mediated, for instance, by host energy constraints. Here, we investigated to what extent stress imposed by predation threat and environmental pollutants influences host-parasite interactions. We challenged the crustacean host Daphnia magna with the sterilizing bacterial endoparasite Pasteuria ramosa and simultaneously exposed the host to fish kairomones, the pesticide carbaryl or both stressors. While parasite virulence, measured as impact on host mortality and sterilization, increased markedly after short-term pesticide exposure, it was not influenced by predation threat. Parasite fitness, measured in terms of produced transmission stages, decreased both in fish and pesticide treatments. This effect was much stronger under predation threat than carbaryl exposure, and was attributable to reduced somatic growth of the host, presumably resulting in fewer resources for parasite development. While the indirect impact of both stressors on spore loads provides evidence for host condition-dependent parasite fitness, the finding of increased virulence only under carbaryl exposure indicates a stronger physiological impact of the neurotoxic chemical compared with the effect of a non-toxic fish kairomone.

Collective defence portfolios of ant hosts shift with social parasite pressure.

PubMed

Jongepier, Evelien; Kleeberg, Isabelle; Job, Sylwester; Foitzik, Susanne

2014-09-22

Host defences become increasingly costly as parasites breach successive lines of defence. Because selection favours hosts that successfully resist parasitism at the lowest possible cost, escalating coevolutionary arms races are likely to drive host defence portfolios towards ever more expensive strategies. We investigated the interplay between host defence portfolios and social parasite pressure by comparing 17 populations of two Temnothorax ant species. When successful, collective aggression not only prevents parasitation but also spares host colonies the cost of searching for and moving to a new nest site. However, once parasites breach the host's nest defence, host colonies should resort to flight as the more beneficial resistance strategy. We show that under low parasite pressure, host colonies more likely responded to an intruding Protomognathus americanus slavemaker with collective aggression, which prevented the slavemaker from escaping and potentially recruiting nest-mates. However, as parasite pressure increased, ant colonies of both host species became more likely to flee rather than to fight. We conclude that host defence portfolios shift consistently with social parasite pressure, which is in accordance with the degeneration of frontline defences and the evolution of subsequent anti-parasite strategies often invoked in hosts of brood parasites. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Is there more than one way to skin a newt? Convergent toxin resistance in snakes is not due to a common genetic mechanism.

PubMed

Feldman, C R; Durso, A M; Hanifin, C T; Pfrender, M E; Ducey, P K; Stokes, A N; Barnett, K E; Brodie, E D; Brodie, E D

2016-01-01

Convergent evolution of tetrodotoxin (TTX) resistance, at both the phenotypic and genetic levels, characterizes coevolutionary arms races between amphibians and their snake predators around the world, and reveals remarkable predictability in the process of adaptation. Here we examine the repeatability of the evolution of TTX resistance in an undescribed predator-prey relationship between TTX-bearing Eastern Newts (Notophthalmus viridescens) and Eastern Hog-nosed Snakes (Heterodon platirhinos). We found that that local newts contain levels of TTX dangerous enough to dissuade most predators, and that Eastern Hog-nosed Snakes within newt range are highly resistant to TTX. In fact, these populations of Eastern Hog-nosed Snakes are so resistant to TTX that the potential for current reciprocal selection might be limited. Unlike all other cases of TTX resistance in vertebrates, H. platirhinos lacks the adaptive amino acid substitutions in the skeletal muscle sodium channel that reduce TTX binding, suggesting that physiological resistance in Eastern Hog-nosed Snakes is conferred by an alternate genetic mechanism. Thus, phenotypic convergence in this case is not due to parallel molecular evolution, indicating that there may be more than one way for this adaptation to arise, even among closely related species.

Is there more than one way to skin a newt? Convergent toxin resistance in snakes is not due to a common genetic mechanism

PubMed Central

Feldman, C R; Durso, A M; Hanifin, C T; Pfrender, M E; Ducey, P K; Stokes, A N; Barnett, K E; Brodie III, E D; Brodie Jr, E D

2016-01-01

Convergent evolution of tetrodotoxin (TTX) resistance, at both the phenotypic and genetic levels, characterizes coevolutionary arms races between amphibians and their snake predators around the world, and reveals remarkable predictability in the process of adaptation. Here we examine the repeatability of the evolution of TTX resistance in an undescribed predator–prey relationship between TTX-bearing Eastern Newts (Notophthalmus viridescens) and Eastern Hog-nosed Snakes (Heterodon platirhinos). We found that that local newts contain levels of TTX dangerous enough to dissuade most predators, and that Eastern Hog-nosed Snakes within newt range are highly resistant to TTX. In fact, these populations of Eastern Hog-nosed Snakes are so resistant to TTX that the potential for current reciprocal selection might be limited. Unlike all other cases of TTX resistance in vertebrates, H. platirhinos lacks the adaptive amino acid substitutions in the skeletal muscle sodium channel that reduce TTX binding, suggesting that physiological resistance in Eastern Hog-nosed Snakes is conferred by an alternate genetic mechanism. Thus, phenotypic convergence in this case is not due to parallel molecular evolution, indicating that there may be more than one way for this adaptation to arise, even among closely related species. PMID:26374236

Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet.

PubMed

Petschenka, Georg; Agrawal, Anurag A

2015-11-07

Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium-potassium pump (Na(+)/K(+)-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na(+)/K(+)-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na(+)/K(+)-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na(+)/K(+)-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na(+)/K(+)-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na(+)/K(+)-ATPase, but had systematically reduced effects on Na(+)/K(+)-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na(+)/K(+)-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects. © 2015 The Author(s).

Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet

PubMed Central

Petschenka, Georg; Agrawal, Anurag A.

2015-01-01

Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium–potassium pump (Na+/K+-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na+/K+-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na+/K+-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na+/K+-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na+/K+-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na+/K+-ATPase, but had systematically reduced effects on Na+/K+-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na+/K+-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects. PMID:26538594

Teaching Nuclear Issues. Occasional Paper No. 10.

ERIC Educational Resources Information Center

Hicks, David W.

The nuclear debate is one of critical importance and should be explored as part of the school curriculum. The psychology of denying the issue of nuclear arms and the psychological effects of the arms race on children is examined in this paper. A number of topics that might be included in discussion of nuclear issues are the arms race, politics,…

75 FR 22384 - Ball Bearings and Parts Thereof From France, Germany, Italy, Japan, and the United Kingdom...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-28

... orders cover all the subject bearings and parts thereof (inner race, outer race, cage, rollers, balls... producer, i.e., sales were made at arm's-length prices. See 19 CFR 351.403(c). We excluded from our... arm's-length prices. To test whether these sales were made at arm's-length prices, we compared the...

In Vitro "Evolutionary Arms-Races" Between Hosts and Parasites in an Artificial RNA Replication System

NASA Astrophysics Data System (ADS)

Furubayashi, T.; Bansho, Y.; Motooka, D.; Nakamura, S.; Ichihashi, N.

2017-07-01

We performed coevolution of artificial RNA self-replicators and parasitic replicators in microdroplets. We observed evolutionary arms-races with oscillating population dynamics and faster evolution of self-replicators caused by parasitic replicators.

Science, Technology and the Nuclear Arms Race

NASA Astrophysics Data System (ADS)

Schroeer, Dietrich

1984-09-01

A comprehensive survey of the nuclear arms race from a technological point of view, which will appeal to the scientist and non-scientist alike. Provides information for the layman on this current topic and is designed for undergraduate courses in political science, history, international studies, as well as physics courses on the subject. Explores the motivation behind the development of various nuclear arms technologies and their deployment and examines the effects these technologies have on military, political and social strategies. Discusses the nature of deterrence and alternatives to it, arms control, and disarmament.

Limits of Military Power for National Security.

ERIC Educational Resources Information Center

Melman, Seymour

1981-01-01

Reviews the post World War II nuclear-military arms race and claims that it is possible to define significant limits of military power for national security. Topics discussed include public opinion regarding the arms race, constraints on military power, conventional forces, checkmating conventional strategy, and the seriousness of nuclear false…

Coevolutionary Free Lunches

NASA Technical Reports Server (NTRS)

Wolpert, David H.; Macready, William G.

2005-01-01

Recent work on the foundations of optimization has begun to uncover its underlying rich structure. In particular, the "No Free Lunch" (NFL) theorems [WM97] state that any two algorithms are equivalent when their performance is averaged across all possible problems. This highlights the need for exploiting problem-specific knowledge to achieve better than random performance. In this paper we present a general framework covering most search scenarios. In addition to the optimization scenarios addressed in the NFL results, this framework covers multi-armed bandit problems and evolution of multiple co-evolving agents. As a particular instance of the latter, it covers "self-play" problems. In these problems the agents work together to produce a champion, who then engages one or more antagonists in a subsequent multi-player game In contrast to the traditional optimization case where the NFL results hold, we show that in self-play there are free lunches: in coevolution some algorithms have better performance than other algorithms, averaged across all possible problems. However in the typical coevolutionary scenarios encountered in biology, where there is no champion, NFL still holds.

Chaotic evolution of arms races

NASA Astrophysics Data System (ADS)

Tomochi, Masaki; Kono, Mitsuo

1998-12-01

A new set of model equations is proposed to describe the evolution of the arms race, by extending Richardson's model with special emphases that (1) power dependent defensive reaction or historical enmity could be a motive force to promote armaments, (2) a deterrent would suppress the growth of armaments, and (3) the defense reaction of one nation against the other nation depends nonlinearly on the difference in armaments between two. The set of equations is numerically solved to exhibit stationary, periodic, and chaotic behavior depending on the combinations of parameters involved. The chaotic evolution is realized when the economic situation of each country involved in the arms race is quite different, which is often observed in the real world.

Technology Creep and the Arms Race: ICBM Problem a Sleeper.

PubMed

Shapley, D

1978-09-22

In three articles, Science will discuss how the creep of technology affects the arms race. The first two articles will deal with the most important current example: first, how ICBM modernization is giving both sides a destabilizing, first-strike capability, and second, how arms control seems to be dealing inadequately with this pressing problem. The third article will describe other cases of incremental technical improvements affecting arms control, such as antisatellite research and ballistic missile defense research, which are bringing both sides closer to the antiballistic missile capability they forswore in a 1972 treaty.

An arms race between producers and scroungers can drive the evolution of social cognition

PubMed Central

2014-01-01

The “social intelligence hypothesis” states that the need to cope with complexities of social life has driven the evolution of advanced cognitive abilities. It is usually invoked in the context of challenges arising from complex intragroup structures, hierarchies, and alliances. However, a fundamental aspect of group living remains largely unexplored as a driving force in cognitive evolution: the competition between individuals searching for resources (producers) and conspecifics that parasitize their findings (scroungers). In populations of social foragers, abilities that enable scroungers to steal by outsmarting producers, and those allowing producers to prevent theft by outsmarting scroungers, are likely to be beneficial and may fuel a cognitive arms race. Using analytical theory and agent-based simulations, we present a general model for such a race that is driven by the producer–scrounger game and show that the race’s plausibility is dramatically affected by the nature of the evolving abilities. If scrounging and scrounging avoidance rely on separate, strategy-specific cognitive abilities, arms races are short-lived and have a limited effect on cognition. However, general cognitive abilities that facilitate both scrounging and scrounging avoidance undergo stable, long-lasting arms races. Thus, ubiquitous foraging interactions may lead to the evolution of general cognitive abilities in social animals, without the requirement of complex intragroup structures. PMID:24822021

The Evolutionary Histories of Antiretroviral Proteins SERINC3 and SERINC5 Do Not Support an Evolutionary Arms Race in Primates.

PubMed

Murrell, Ben; Vollbrecht, Thomas; Guatelli, John; Wertheim, Joel O

2016-09-15

Molecular evolutionary arms races between viruses and their hosts are important drivers of adaptation. These Red Queen dynamics have been frequently observed in primate retroviruses and their antagonists, host restriction factor genes, such as APOBEC3F/G, TRIM5-α, SAMHD1, and BST-2. Host restriction factors have experienced some of the most intense and pervasive adaptive evolution documented in primates. Recently, two novel host factors, SERINC3 and SERINC5, were identified as the targets of HIV-1 Nef, a protein crucial for the optimal infectivity of virus particles. Here, we compared the evolutionary fingerprints of SERINC3 and SERINC5 to those of other primate restriction factors and to a set of other genes with diverse functions. SERINC genes evolved in a manner distinct from the canonical arms race dynamics seen in the other restriction factors. Despite their antiviral activity against HIV-1 and other retroviruses, SERINC3 and SERINC5 have a relatively uneventful evolutionary history in primates. Restriction factors are host proteins that block viral infection and replication. Many viruses, like HIV-1 and related retroviruses, evolved accessory proteins to counteract these restriction factors. The importance of these interactions is evidenced by the intense adaptive selection pressures that dominate the evolutionary histories of both the host and viral genes involved in this so-called arms race. The dynamics of these arms races can point to mechanisms by which these viral infections can be prevented. Two human genes, SERINC3 and SERINC5, were recently identified as targets of an HIV-1 accessory protein important for viral infectivity. Unexpectedly, we found that these SERINC genes, unlike other host restriction factor genes, show no evidence of a recent evolutionary arms race with viral pathogens. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

The arms race and nuclear war

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barash, D.P.

Addressing the history, physics, biology, economics, politics, psychology, and ethics of nuclear armaments, the author provides a survey of diverse facets of the nuclear controversy. The study encompasses such key areas as nuclear hardware and technology; the short- and long-term effects of nuclear weapons; strategic doctrine, deterrence and defense policy; the arms race, arms control, and nuclear proliferation; and the economic impact, psychology, and ethics of nuclear armaments. A ''Policy Issues'' section, presenting both the advocate and opponent sides of the debate, is included with each chapter.

A New Framework for Analysis of Coevolutionary Systems-Directed Graph Representation and Random Walks.

PubMed

Chong, Siang Yew; Tiňo, Peter; He, Jun; Yao, Xin

2017-11-20

Studying coevolutionary systems in the context of simplified models (i.e., games with pairwise interactions between coevolving solutions modeled as self plays) remains an open challenge since the rich underlying structures associated with pairwise-comparison-based fitness measures are often not taken fully into account. Although cyclic dynamics have been demonstrated in several contexts (such as intransitivity in coevolutionary problems), there is no complete characterization of cycle structures and their effects on coevolutionary search. We develop a new framework to address this issue. At the core of our approach is the directed graph (digraph) representation of coevolutionary problems that fully captures structures in the relations between candidate solutions. Coevolutionary processes are modeled as a specific type of Markov chains-random walks on digraphs. Using this framework, we show that coevolutionary problems admit a qualitative characterization: a coevolutionary problem is either solvable (there is a subset of solutions that dominates the remaining candidate solutions) or not. This has an implication on coevolutionary search. We further develop our framework that provides the means to construct quantitative tools for analysis of coevolutionary processes and demonstrate their applications through case studies. We show that coevolution of solvable problems corresponds to an absorbing Markov chain for which we can compute the expected hitting time of the absorbing class. Otherwise, coevolution will cycle indefinitely and the quantity of interest will be the limiting invariant distribution of the Markov chain. We also provide an index for characterizing complexity in coevolutionary problems and show how they can be generated in a controlled manner.

Natural History of Innate Host Defense Peptides.

PubMed

Linde, A; Wachter, B; Höner, O P; Dib, L; Ross, C; Tamayo, A R; Blecha, F; Melgarejo, T

2009-12-01

Host defense peptides act on the forefront of innate immunity, thus playing a central role in the survival of animals and plants. Despite vast morphological changes in species through evolutionary history, all animals examined to date share common features in their innate immune defense strategies, hereunder expression of host defense peptides (HDPs). Most studies on HDPs have focused on humans, domestic and laboratory animals. More than a thousand different sequences have been identified, yet data on HDPs in wild-living animals are sparse. The biological functions of HDPs include broad-spectrum antimicrobial activity and immunomodulation. Natural selection and coevolutionary host-pathogen arms race theory suggest that the extent and specificity of the microbial load influences the spectrum and potency of HDPs in different species. Individuals of extant species-that have lived for an extended period in evolutionary history amid populations with intact processes of natural selection-likely possess the most powerful and well-adapted "natural antibiotics". Research on the evolutionary history of the innate defense system and the host in context of the consequences of challenges as well as the efficacy of the innate immune system under natural conditions is therefore of immediate interest. This review focuses on evolutionary aspects of immunophysiology, with emphasis on innate effector molecules. Studies on host defense in wild-living animals may significantly enhance our understanding of inborn immune mechanisms, and help identify molecules that may assist us to cope better with the increasing microbial challenges that likely follow from the continuous amplification of biodiversity levels on Earth.

Entomopathogenic Fungi: New Insights into Host-Pathogen Interactions.

PubMed

Butt, T M; Coates, C J; Dubovskiy, I M; Ratcliffe, N A

2016-01-01

Although many insects successfully live in dangerous environments exposed to diverse communities of microbes, they are often exploited and killed by specialist pathogens. Studies of host-pathogen interactions (HPI) provide valuable insights into the dynamics of the highly aggressive coevolutionary arms race between entomopathogenic fungi (EPF) and their arthropod hosts. The host defenses are designed to exclude the pathogen or mitigate the damage inflicted while the pathogen responds with immune evasion and utilization of host resources. EPF neutralize their immediate surroundings on the insect integument and benefit from the physiochemical properties of the cuticle and its compounds that exclude competing microbes. EPF also exhibit adaptations aimed at minimizing trauma that can be deleterious to both host and pathogen (eg, melanization of hemolymph), form narrow penetration pegs that alleviate host dehydration and produce blastospores that lack immunogenic sugars/enzymes but facilitate rapid assimilation of hemolymph nutrients. In response, insects deploy an extensive armory of hemocytes and macromolecules, such as lectins and phenoloxidase, that repel, immobilize, and kill EPF. New evidence suggests that immune bioactives work synergistically (eg, lysozyme with antimicrobial peptides) to combat infections. Some proteins, including transferrin and apolipophorin III, also demonstrate multifunctional properties, participating in metabolism, homeostasis, and pathogen recognition. This review discusses the molecular intricacies of these HPI, highlighting the interplay between immunity, stress management, and metabolism. Increased knowledge in this area could enhance the efficacy of EPF, ensuring their future in integrated pest management programs. Copyright © 2016 Elsevier Inc. All rights reserved.

Horned lizards (Phrynosoma) incapacitate dangerous ant prey with mucus.

PubMed

Sherbrooke, Wade C; Schwenk, Kurt

2008-10-01

Horned lizards (Iguanidae, Phrynosomatinae, Phrynosoma) are morphologically specialized reptiles characterized by squat, tank-like bodies, short limbs, blunt snouts, spines and cranial horns, among other traits. They are unusual among lizards in the degree to which they specialize on a diet of ants, but exceptional in the number of pugnacious, highly venomous, stinging ants they consume, especially harvester ants (genus Pogonomyrmex). Like other iguanian lizards, they capture insect prey on the tongue, but unlike other lizards, they neither bite nor chew dangerous prey before swallowing. Instead, they employ a unique kinematic pattern in which prey capture, transport and swallowing are combined. Nevertheless, horned lizards consume dozens of harvester ants without harm. We show that their derived feeding kinematics are associated with unique, mucus-secreting pharyngeal papillae that apparently serve to immobilize and incapacitate dangerous ants as they are swallowed by compacting them and binding them in mucus strands. Radially branched esophageal folds provide additional mucus-secreting surfaces the ants pass through as they are swallowed. Ants extracted from fresh-killed horned lizard stomachs are curled ventrally into balls and bound in mucus. We conclude that the pharyngeal papillae, in association with a unique form of hyolingual prey transport and swallowing, are horned lizard adaptations related to a diet of dangerous prey. Harvester ant defensive weapons, along with horned lizard adaptations against such weapons, suggest a long-term, predator-prey, co-evolutionary arms race between Phrynosoma and Pogonomyrmex. Copyright 2008 Wiley-Liss, Inc.

Destruction before detonation: the impact of the arms race on health and health care.

PubMed

Sidel, V W

1985-12-07

Health workers are urged to help end the arms race and advocate that nations transfer funds from nuclear weapons to human services. Statistics on morbidity and mortality in developing countries, hunger and the lack of medical care and resources, and the need for preventive medicine rather than military buildups are discussed. It is contended that even small conversions of funds spent on arms to spending on health could produce enormous benefits, reducing the numbers of children who die daily from preventable illnesses.

The next great arms race

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klare, M.T.

Fueled by dramatic economic growth, the nations of East and Southeast Asia are engaged in an arms race that shows every sign of accelerating. These countries are importing not only complex weapon systems but, more important, the technology with which to manufacture them. Since longstanding territorial and border disputes remain (most notably in the South China Sea) and the twin threats of China and Japan loom large, the potential for conflicts is great. Without arms control and regional security measures, the Pacific Rim could one day be the site of a major conflagration.

Testing for coevolutionary diversification: linking pattern with process.

PubMed

Althoff, David M; Segraves, Kari A; Johnson, Marc T J

2014-02-01

Coevolutionary diversification is cited as a major mechanism driving the evolution of diversity, particularly in plants and insects. However, tests of coevolutionary diversification have focused on elucidating macroevolutionary patterns rather than the processes giving rise to such patterns. Hence, there is weak evidence that coevolution promotes diversification. This is in part due to a lack of understanding about the mechanisms by which coevolution can cause speciation and the difficulty of integrating results across micro- and macroevolutionary scales. In this review, we highlight potential mechanisms of coevolutionary diversification, outline approaches to examine this process across temporal scales, and propose a set of minimal requirements for demonstrating coevolutionary diversification. Our aim is to stimulate research that tests more rigorously for coevolutionary diversification. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physiological and physical characteristics of elite dragon boat paddlers.

PubMed

Ho, Sarah R; Smith, Richard M; Chapman, Philip G; Sinclair, Peter J; Funato, Kazuo

2013-01-01

The objectives of this study were to profile the physiological and physical characteristics of elite dragon boat paddlers, to identify characteristics that predict race performance and to quantify the metabolic energy contributions to simulated 200-m and 500-m dragon boat racing. Eleven, national level, male, Japanese dragon boat paddlers completed a battery of tests on a paddling ergometer including an incremental maximal aerobic capacity test, a 2-minute maximal accumulated oxygen deficit (MAOD) test, and simulated 200-m and 500-m races. A physiological and physical profile of subjects was compiled. Results showed that 200-m race performance correlated with flexed arm girth and excess postexercise oxygen consumption (EPOC) measured in the 30 minutes after the MAOD test, whereas 500-m race performance correlated with body fat percentage, relaxed and flexed arm girth, MAOD, EPOC, and peak power during the MAOD test. Stepwise multiple regression revealed that flexed arm girth was the most powerful predictor of 200-m and 500-m race performance, followed by EPOC with the combination of these 2 factors able to explain 74% and 68% of the variance in 200-m and 500-m race performance, respectively. Aerobic energy contributions for 200-m (50 seconds) and 500-m (1 minute 50 seconds) races were (mean (95% confidence intervals)) 52.1% (range, 47.4-56.8%) and 67.5% (range, 60.1-77.8%), respectively. In conclusion, coaches should develop training programs targeted at developing upper-body musculature and increasing anaerobic capacity because these factors are the strongest predictors of 200-m and 500-m race performance. Given the substantial aerobic energy contributions even for a 200-m race event, coaches should aim to increase the maximal aerobic capacity of the paddler in preparation for both 200-m and 500-m events.

Spreading of multiple epidemics with cross immunization.

PubMed

Uekermann, Florian; Sneppen, Kim

2012-09-01

Pathogen-host relationships are the result of an ongoing coevolutionary race where the immune system of the host attempts to eliminate the pathogen, while the successful pathogen mutates to become invisible for the host's immune system. We here propose a minimal pathogen-host evolution model that takes into account cross immunization and allows for evolution of a spatially heterogeneous immune status of a population of hosts. With only the mutation rate as a determining parameter, the model allows us to produce an evolutionary tree of diseases which is highly branched, but hardly ever splits into separate long-lived trunks. Side branches remain short lived and seldom diverge to the extent of losing all cross immunizations.

[Arms racing between human beings and pathogens: NDM-1 and superbugs].

PubMed

Sun, Mingwei; Zheng, Beiwen; Gao, George F; Zhu, Baoli

2010-11-01

Throughout human history, pandemic bacterial diseases such as the plague and tuberculosis have posed an enormous threat to human beings. The discovery of antibiotics has provided us with powerful arsenal for the defense against bacterial infections. However, bacteria are acquiring more and more resistance genes to shield off antibiotics through mutation and horizontal gene transfer. Therefore, novel antibiotics must be produced and the arms race between bacterial pathogens and antibiotics is becoming increasingly intense. Recently, researchers have found that plasmids carrying a new metallo-beta-lactamase gene, blaNDM-1, and many other antibiotics resistance genes can easily spread through bacterial populations and confer recipient stains resistance to nearly all of the current antibiotics. It is a threat to the human health and a great challenge for our medical science, which we are facing. We need to find new ways to fight and win this arms racing.

The role of ecology, neutral processes and antagonistic coevolution in an apparent sexual arms race.

PubMed

Perry, Jennifer C; Garroway, Colin J; Rowe, Locke

2017-09-01

Some of the strongest examples of a sexual 'arms race' come from observations of correlated evolution in sexually antagonistic traits among populations. However, it remains unclear whether these cases truly represent sexually antagonistic coevolution; alternatively, ecological or neutral processes might also drive correlated evolution. To investigate these alternatives, we evaluated the contributions of intersex genetic correlations, ecological context, neutral genetic divergence and sexual coevolution in the correlated evolution of antagonistic traits among populations of Gerris incognitus water striders. We could not detect intersex genetic correlations for these sexually antagonistic traits. Ecological variation was related to population variation in the key female antagonistic trait (spine length, a defence against males), as well as body size. Nevertheless, population covariation between sexually antagonistic traits remained substantial and significant even after accounting for all of these processes. Our results therefore provide strong evidence for a contemporary sexual arms race. © 2017 John Wiley & Sons Ltd/CNRS.

Evolutionary disarmament in interspecific competition.

PubMed

Kisdi, E; Geritz, S A

2001-12-22

Competitive asymmetry, which is the advantage of having a larger body or stronger weaponry than a contestant, drives spectacular evolutionary arms races in intraspecific competition. Similar asymmetries are well documented in interspecific competition, yet they seldom lead to exaggerated traits. Here we demonstrate that two species with substantially different size may undergo parallel coevolution towards a smaller size under the same ecological conditions where a single species would exhibit an evolutionary arms race. We show that disarmament occurs for a wide range of parameters in an ecologically explicit model of competition for a single shared resource; disarmament also occurs in a simple Lotka-Volterra competition model. A key property of both models is the interplay between evolutionary dynamics and population density. The mechanism does not rely on very specific features of the model. Thus, evolutionary disarmament may be widespread and may help to explain the lack of interspecific arms races.

Evolutionary disarmament in interspecific competition.

PubMed Central

Kisdi, E.; Geritz, S. A.

2001-01-01

Competitive asymmetry, which is the advantage of having a larger body or stronger weaponry than a contestant, drives spectacular evolutionary arms races in intraspecific competition. Similar asymmetries are well documented in interspecific competition, yet they seldom lead to exaggerated traits. Here we demonstrate that two species with substantially different size may undergo parallel coevolution towards a smaller size under the same ecological conditions where a single species would exhibit an evolutionary arms race. We show that disarmament occurs for a wide range of parameters in an ecologically explicit model of competition for a single shared resource; disarmament also occurs in a simple Lotka-Volterra competition model. A key property of both models is the interplay between evolutionary dynamics and population density. The mechanism does not rely on very specific features of the model. Thus, evolutionary disarmament may be widespread and may help to explain the lack of interspecific arms races. PMID:11749715

Brain activation underlying threat detection to targets of different races.

PubMed

Senholzi, Keith B; Depue, Brendan E; Correll, Joshua; Banich, Marie T; Ito, Tiffany A

2015-01-01

The current study examined blood oxygen level-dependent signal underlying racial differences in threat detection. During functional magnetic resonance imaging, participants determined whether pictures of Black or White individuals held weapons. They were instructed to make shoot responses when the picture showed armed individuals but don't shoot responses to unarmed individuals, with the cost of not shooting armed individuals being greater than that of shooting unarmed individuals. Participants were faster to shoot armed Blacks than Whites, but faster in making don't shoot responses to unarmed Whites than Blacks. Brain activity differed to armed versus unarmed targets depending on target race, suggesting different mechanisms underlying threat versus safety decisions. Anterior cingulate cortex was preferentially engaged for unarmed Whites than Blacks. Parietal and visual cortical regions exhibited greater activity for armed Blacks than Whites. Seed-based functional connectivity of the amygdala revealed greater coherence with parietal and visual cortices for armed Blacks than Whites. Furthermore, greater implicit Black-danger associations were associated with increased amygdala activation to armed Blacks, compared to armed Whites. Our results suggest that different neural mechanisms may underlie racial differences in responses to armed versus unarmed targets.

Adaptive Evolution of the Venom-Targeted vWF Protein in Opossums that Eat Pitvipers

PubMed Central

Jansa, Sharon A.; Voss, Robert S.

2011-01-01

The rapid evolution of venom toxin genes is often explained as the result of a biochemical arms race between venomous animals and their prey. However, it is not clear that an arms race analogy is appropriate in this context because there is no published evidence for rapid evolution in genes that might confer toxin resistance among routinely envenomed species. Here we report such evidence from an unusual predator-prey relationship between opossums (Marsupialia: Didelphidae) and pitvipers (Serpentes: Crotalinae). In particular, we found high ratios of replacement to silent substitutions in the gene encoding von Willebrand Factor (vWF), a venom-targeted hemostatic blood protein, in a clade of opossums known to eat pitvipers and to be resistant to their hemorrhagic venom. Observed amino-acid substitutions in venom-resistant opossums include changes in net charge and hydrophobicity that are hypothesized to weaken the bond between vWF and one of its toxic snake-venom ligands, the C-type lectin-like protein botrocetin. Our results provide the first example of rapid adaptive evolution in any venom-targeted molecule, and they support the notion that an evolutionary arms race might be driving the rapid evolution of snake venoms. However, in the arms race implied by our results, venomous snakes are prey, and their venom has a correspondingly defensive function in addition to its usual trophic role. PMID:21731638

Estimation of true height: a study in population-specific methods among young South African adults.

PubMed

Lahner, Christen Renée; Kassier, Susanna Maria; Veldman, Frederick Johannes

2017-02-01

To investigate the accuracy of arm-associated height estimation methods in the calculation of true height compared with stretch stature in a sample of young South African adults. A cross-sectional descriptive design was employed. Pietermaritzburg, Westville and Durban, KwaZulu-Natal, South Africa, 2015. Convenience sample (N 900) aged 18-24 years, which included an equal number of participants from both genders (150 per gender) stratified across race (Caucasian, Black African and Indian). Continuous variables that were investigated included: (i) stretch stature; (ii) total armspan; (iii) half-armspan; (iv) half-armspan ×2; (v) demi-span; (vi) demi-span gender-specific equation; (vii) WHO equation; and (viii) WHO-adjusted equations; as well as categorization according to gender and race. Statistical analysis was conducted using IBM SPSS Statistics Version 21.0. Significant correlations were identified between gender and height estimation measurements, with males being anatomically larger than females (P<0·001). Significant differences were documented when study participants were stratified according to race and gender (P<0·001). Anatomical similarities were noted between Indians and Black Africans, whereas Caucasians were anatomically different from the other race groups. Arm-associated height estimation methods were able to estimate true height; however, each method was specific to each gender and race group. Height can be calculated by using arm-associated measurements. Although universal equations for estimating true height exist, for the enhancement of accuracy, the use of equations that are race-, gender- and population-specific should be considered.

The Natural History of the South Hills Crossbill in Relation to Its Impending Extinction.

PubMed

Benkman, Craig W

2016-12-01

Increasingly, the species that we discover will be uncommon, area restricted, and vulnerable to extinction. I describe the natural history of a newly discovered seed-eating finch from the Rocky Mountain region, the South Hills crossbill (Loxia curvirostra complex). It relies on seeds in the closed cones of the fire-adapted Rocky Mountain lodgepole pine (Pinus contorta latifolia) and is found only in the higher elevations of two small mountain ranges in southern Idaho. Here crossbills and pine are engaged in a coevolutionary arms race. Although most of the seeds remain secured within the cones for decades until the heat of a stand-replacing fire causes the cone scales to separate, seeds become accessible to crossbills slowly as cones weather and gaps form between some of the scales. However, hot days (≥32°C), especially four or more hot days, seem to mimic the effect of fire, apparently causing the immediate release of a fraction of the seeds. Such events caused a 20% annual decline in crossbills that lasted up to 4 years and an 80% decline in the population between 2003 and 2011. This is an example of a novel trophic mismatch between a consumer and its resource caused by a shift in the phenology of the resource arising from climate change. Not only do these phenological shifts have the potential to cause seed consumers to decline, these shifts are also likely to cause reduced recruitment of the plants. The South Hills crossbill is especially vulnerable and will likely go extinct this century before lodgepole pine is extirpated from the South Hills.

Life history and biology of Fascioloides magna (Trematoda) and its native and exotic hosts

PubMed Central

Malcicka, Miriama

2015-01-01

Host–parasite interactions are model systems in a wide range of ecological and evolutionary fields and may be utilized for testing numerous theories and hypotheses in terms of both applied and fundamental research. For instance, they are important in terms of studying coevolutionary arms races, species invasions, and in economic terms the health of livestock and humans. Here, I present a comprehensive description of the life history, biogeography, and biology of the giant liver fluke, Fascioloides magna, and both its intermediate and definitive hosts. F. magna is native to North America where it uses several species of freshwater snails (Lymnaeidae) as intermediate hosts and four main species of ungulates as definitive hosts. The fluke has also been introduced into parts of Europe where it is now established in two lymnaeid snail species and three ungulate species. This study gives a comprehensive description of different developmental stages of the fluke in its two host classes, as well as detailed notes on historical and present distributions of F. magna in North America and Europe as well as in its snail and deer hosts (with range maps provided). Aberrant and dead-end hosts are also discussed in detail, and descriptive phylogenies are provided for all of the organisms. I briefly discuss how F. magna represents a model example of multiple-level ecological fitting, a phenomenon not yet described in the empirical literature. Lastly, I explore possible future scenarios for fluke invasion in Europe, where it is currently expanding its range. PMID:25897378

Expression plasticity and evolutionary changes extensively shape the sugar-mimic alkaloid adaptation of non-digestive glucosidase in lepidopteran mulberry-specialist insects.

PubMed

Li, Xiaotong; Shi, Liangen; Dai, Xiangping; Chen, Yajie; Xie, Hongqing; Feng, Min; Chen, Yuyin; Wang, Huabing

2018-05-12

During the co-evolutionary arms race between plants and herbivores, insects evolved systematic adaptive plasticity to minimise the chemical defence effects of their host plants. Previous studies mainly focused on the expressional plasticity of enzymes in detoxification and digestion. However, the expressional response and adaptive evolution of other fundamental regulators against host phytochemicals are largely unknown. Glucosidase II (GII), which is composed of a catalytic GIIα subunit and a regulatory GIIβ subunit, is an evolutionarily conserved enzyme that regulates glycoprotein folding. In this study, we found that GIIα expression of the mulberry-specialist insect was significantly induced by mulberry leaf extract, 1-Deoxynojirimycin (1-DNJ), whereas GIIβ transcripts were not significantly changed. Moreover, positive selection was detected in GIIα when the mulberry-specialist insects diverged from the lepidopteran order; whereas GIIβ was mainly subjected to purifying selection, thus indicating an asymmetrically selective pressure of GII subunits. In addition, positively selected sites were enriched in the GIIα of mulberry-specialist insects, and located around the 1-DNJ binding sites and in the C-terminal region, which could result in conformational changes that affect catalytic activity and substrate-binding efficiency. These results show that expression plasticity and evolutionary changes extensively shape sugar-mimic alkaloids adaptation of non-digestive glucosidase in lepidopteran mulberry-specialist insects. Our study provides novel insights into a deep understanding of the sequestration and adaptation of phytophagous specialists to host defensive compounds. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The "Cheshire Cat" escape strategy of the coccolithophore Emiliania huxleyi in response to viral infection.

PubMed

Frada, Miguel; Probert, Ian; Allen, Michael J; Wilson, William H; de Vargas, Colomban

2008-10-14

The coccolithophore Emiliania huxleyi is one of the most successful eukaryotes in modern oceans. The two phases in its haplodiploid life cycle exhibit radically different phenotypes. The diploid calcified phase forms extensive blooms, which profoundly impact global biogeochemical equilibria. By contrast, the ecological role of the noncalcified haploid phase has been completely overlooked. Giant phycodnaviruses (Emiliania huxleyi viruses, EhVs) have been shown to infect and lyse diploid-phase cells and to be heavily implicated in the regulation of populations and the termination of blooms. Here, we demonstrate that the haploid phase of E. huxleyi is unrecognizable and therefore resistant to EhVs that kill the diploid phase. We further show that exposure of diploid E. huxleyi to EhVs induces transition to the haploid phase. Thus we have clearly demonstrated a drastic difference in viral susceptibility between life cycle stages with different ploidy levels in a unicellular eukaryote. Resistance of the haploid phase of E. huxleyi provides an escape mechanism that involves separation of meiosis from sexual fusion in time, thus ensuring that genes of dominant diploid clones are passed on to the next generation in a virus-free environment. These "Cheshire Cat" ecological dynamics release host evolution from pathogen pressure and thus can be seen as an opposite force to a classic "Red Queen" coevolutionary arms race. In E. huxleyi, this phenomenon can account for the fact that the selective balance is tilted toward the boom-and-bust scenario of optimization of both growth rates of calcifying E. huxleyi cells and infectivity of EhVs.

Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole

PubMed Central

Bennett, Gordon M.; Moran, Nancy A.

2015-01-01

Many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. A model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and Buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. Symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritable symbiosis. Receiving less attention are potential negative ramifications of symbiotic alliances. In the short run, symbionts impose metabolic costs. Over evolutionary time, hosts evolve dependence beyond the original benefits of the symbiosis. Symbiotic partners enter into an evolutionary spiral that leads to irreversible codependence and associated risks. Host adaptations to symbiosis (e.g., immune-system modification) may impose vulnerabilities. Symbiont genomes also continuously accumulate deleterious mutations, limiting their beneficial contributions and environmental tolerance. Finally, the fitness interests of obligate heritable symbionts are distinct from those of their hosts, leading to selfish tendencies. Thus, genes underlying the host–symbiont interface are predicted to follow a coevolutionary arms race, as observed for genes governing host–pathogen interactions. On the macroevolutionary scale, the rapid evolution of interacting symbiont and host genes is predicted to accelerate host speciation rates by generating genetic incompatibilities. However, degeneration of symbiont genomes may ultimately limit the ecological range of host species, potentially increasing extinction risk. Recent results for the aphid–Buchnera symbiosis and related systems illustrate that, whereas heritable symbiosis can expand ecological range and spur diversification, it also presents potential perils. PMID:25713367

Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole.

PubMed

Bennett, Gordon M; Moran, Nancy A

2015-08-18

Many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. A model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and Buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. Symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritable symbiosis. Receiving less attention are potential negative ramifications of symbiotic alliances. In the short run, symbionts impose metabolic costs. Over evolutionary time, hosts evolve dependence beyond the original benefits of the symbiosis. Symbiotic partners enter into an evolutionary spiral that leads to irreversible codependence and associated risks. Host adaptations to symbiosis (e.g., immune-system modification) may impose vulnerabilities. Symbiont genomes also continuously accumulate deleterious mutations, limiting their beneficial contributions and environmental tolerance. Finally, the fitness interests of obligate heritable symbionts are distinct from those of their hosts, leading to selfish tendencies. Thus, genes underlying the host-symbiont interface are predicted to follow a coevolutionary arms race, as observed for genes governing host-pathogen interactions. On the macroevolutionary scale, the rapid evolution of interacting symbiont and host genes is predicted to accelerate host speciation rates by generating genetic incompatibilities. However, degeneration of symbiont genomes may ultimately limit the ecological range of host species, potentially increasing extinction risk. Recent results for the aphid-Buchnera symbiosis and related systems illustrate that, whereas heritable symbiosis can expand ecological range and spur diversification, it also presents potential perils.

The “Cheshire Cat” escape strategy of the coccolithophore Emiliania huxleyi in response to viral infection

PubMed Central

Frada, Miguel; Probert, Ian; Allen, Michael J.; Wilson, William H.; de Vargas, Colomban

2008-01-01

The coccolithophore Emiliania huxleyi is one of the most successful eukaryotes in modern oceans. The two phases in its haplodiploid life cycle exhibit radically different phenotypes. The diploid calcified phase forms extensive blooms, which profoundly impact global biogeochemical equilibria. By contrast, the ecological role of the noncalcified haploid phase has been completely overlooked. Giant phycodnaviruses (Emiliania huxleyi viruses, EhVs) have been shown to infect and lyse diploid-phase cells and to be heavily implicated in the regulation of populations and the termination of blooms. Here, we demonstrate that the haploid phase of E. huxleyi is unrecognizable and therefore resistant to EhVs that kill the diploid phase. We further show that exposure of diploid E. huxleyi to EhVs induces transition to the haploid phase. Thus we have clearly demonstrated a drastic difference in viral susceptibility between life cycle stages with different ploidy levels in a unicellular eukaryote. Resistance of the haploid phase of E. huxleyi provides an escape mechanism that involves separation of meiosis from sexual fusion in time, thus ensuring that genes of dominant diploid clones are passed on to the next generation in a virus-free environment. These “Cheshire Cat” ecological dynamics release host evolution from pathogen pressure and thus can be seen as an opposite force to a classic “Red Queen” coevolutionary arms race. In E. huxleyi, this phenomenon can account for the fact that the selective balance is tilted toward the boom-and-bust scenario of optimization of both growth rates of calcifying E. huxleyi cells and infectivity of EhVs. PMID:18824682

JPRS Report, East Europe

DTIC Science & Technology

1988-12-14

situation in the world healthier, particularly for the program to liquidate nuclear arms and other types of weapons of mass destruction. During the...make preparations for extensive discussions with the aim of radically reducing tactical nuclear weapons, armed forces, and conventional weap- ons...liquidat- ing two classes of nuclear arms as a historic step which will create preconditions for limiting the feverish arms race and for better

Parallel arms races between garter snakes and newts involving tetrodotoxin as the phenotypic interface of coevolution.

PubMed

Brodie, Edmund D; Feldman, Chris R; Hanifin, Charles T; Motychak, Jeffrey E; Mulcahy, Daniel G; Williams, Becky L; Brodie, Edmund D

2005-02-01

Parallel "arms races" involving the same or similar phenotypic interfaces allow inference about selective forces driving coevolution, as well as the importance of phylogenetic and phenotypic constraints in coevolution. Here, we report the existence of apparent parallel arms races between species pairs of garter snakes and their toxic newt prey that indicate independent evolutionary origins of a key phenotype in the interface. In at least one area of sympatry, the aquatic garter snake, Thamnophis couchii, has evolved elevated resistance to the neurotoxin tetrodotoxin (TTX), present in the newt Taricha torosa. Previous studies have shown that a distantly related garter snake, Thamnophis sirtalis, has coevolved with another newt species that possesses TTX, Taricha granulosa. Patterns of within population variation and phenotypic tradeoffs between TTX resistance and sprint speed suggest that the mechanism of resistance is similar in both species of snake, yet phylogenetic evidence indicates the independent origins of elevated resistance to TTX.

Contrasting effects of intralocus sexual conflict on sexually antagonistic coevolution

PubMed Central

Pennell, Tanya M.; de Haas, Freek J. H.; Morrow, Edward H.; van Doorn, G. Sander

2016-01-01

Evolutionary conflict between the sexes can induce arms races in which males evolve traits that are detrimental to the fitness of their female partners, and vice versa. This interlocus sexual conflict (IRSC) has been proposed as a cause of perpetual intersexual antagonistic coevolution with wide-ranging evolutionary consequences. However, theory suggests that the scope for perpetual coevolution is limited, if traits involved in IRSC are subject to pleiotropic constraints. Here, we consider a biologically plausible form of pleiotropy that has hitherto been ignored in treatments of IRSC and arrive at drastically different conclusions. Our analysis is based on a quantitative genetic model of sexual conflict, in which genes controlling IRSC traits have side effects in the other sex, due to incompletely sex-limited gene expression. As a result, the genes are exposed to intralocus sexual conflict (IASC), a tug-of-war between opposing male- and female-specific selection pressures. We find that the interaction between the two forms of sexual conflict has contrasting effects on antagonistic coevolution: Pleiotropic constraints stabilize the dynamics of arms races if the mating traits are close to evolutionary equilibrium but can prevent populations from ever reaching such a state. Instead, the sexes are drawn into a continuous cycle of arms races, causing the buildup of IASC, alternated by phases of IASC resolution that trigger the next arms race. These results encourage an integrative perspective on the biology of sexual conflict and generally caution against relying exclusively on equilibrium stability analysis. PMID:26755609

The common redstart as a suitable model to study cuckoo-host coevolution in a unique ecological context.

PubMed

Samaš, Peter; Rutila, Jarkko; Grim, Tomáš

2016-11-25

Co-evolutionary arms-races result in spatio-temporally dynamic relationships between interacting species, e.g., brood parasites and their avian hosts. However, majority of avian co-evolutionary studies are limited to "snap-shots" of a single breeding season in an open-nesting host. In a long-term study (11 breeding seasons), we explored a unique system between the brood parasitic common cuckoo (Cuculus canorus) and its host, the common redstart (Phoenicurus phoenicurus) which is exceptional among all cuckoo hosts due to being a cavity nester. Conditions in cavities are different from open nests, e.g., lower risks of predation, more favourable microclimate, increased risks of unsuccessful eviction of host offspring by the cuckoo nestling. Different conditions in cavities thus can be expected to shape parasite-host coevolution differently from what is typically studied in open nesting hosts. In our highly parasitised nest-box population (32.5%, n = 569 nests) only 35.7% of cuckoo eggs were laid into the nest cup and incubated by redstarts. Host nests shifted availability to later into the breeding season from 2006 to 2016 and cuckoos followed this trend by also shifting their timing of parasitism. Although previous studies revealed that redstarts selectively eject experimental non-mimetic eggs (desertion was not a specific response to foreign eggs), the hosts never ejected naturally-laid cuckoo eggs or cuckoo eggs cross-fostered into naturally non-parasitised nests. We solve the long-standing debate about the origin of cuckoo eggs found on the nest rim: we gained the first direct video-recording evidence that eggs found on the nest rim were mislaid by parasites and not ejected by hosts. Naturally-parasitised nests were deserted more often (18.6%) than control non-parasitized nests (5.6%) or nests artificially parasitised by us (1.4%). This suggests that the sight of the laying cuckoo female is the primary cue that triggers egg rejection (by desertion) in this host. Review of data from this and other study sites (10 populations, n = 853 experiments) demonstrates high variability in rejection rates and shows that populations facing higher parasitism rates reject parasitic eggs with higher frequencies. Surprisingly, cuckoo chicks either growing solitarily or with redstart chicks did not differ in their fledging success. We suggest that the redstart is an ideal model system to study the flexibility and limits of brood parasite-host co-evolution in an extreme ecological setting.

Case Study: Physical Capacity and Nutritional Status Before and After a Single-Handed Yacht Race.

PubMed

Ghiani, Giovanna; Magnani, Sara; Doneddu, Azzurra; Sainas, Gianmarco; Pinna, Virginia; Caboi, Marco; Palazzolo, Girolamo; Tocco, Filippo; Crisafulli, Antonio

2018-06-12

During solitary sailing, the sailor is exposed to sleep deprivation and difficulties in consuming regular meals. Sailor weight loss is often reported. In the present case study, we describe changes in the physical capacity and nutritional status of an athlete attempting a single-handed yacht race around the globe. An Italian male ocean racer (Gaetano Mura) asked for our help to reach an optimum level of physical and nutritional preparation. We planned his diet after assessing his anthropometric parameters and body composition, as well as his usual energy intake and nutritional expenditure. The diet consisted of 120 meals stored in sealed plastic bags. Before his departure, GM performed two incremental exercise tests (cycle ergometry and arm crank ergometry) to assess his physical capacity. Cardiac functions were also estimated by Doppler echocardiography. All measures and exercise tests were repeated 10 days after GM finished the race, which lasted 64 days. Anthropometric measures did not change significantly, with the exception of arm fat area and thigh muscle area, which decreased. There were evident increments in maximum oxygen intake and maximum workload during arm cranking after the race. On the contrary, maximum oxygen uptake and maximum workload decreased during cycling. Finally, end-diastolic and stroke volume decreased after the race. It was concluded that nutritional counseling was useful to avoid excessive changes in nutritional status and body composition due to 64 days of solitary navigation. However, a reduction in physical leg capacity and cardiovascular functions secondary to leg disuse were present.

Reactivity, stability, and strength performance capacity in motor sports.

PubMed

Baur, H; Müller, S; Hirschmüller, A; Huber, G; Mayer, F

2006-11-01

Racing drivers require multifaceted cognitive and physical abilities in a multitasking situation. A knowledge of their physical capacities may help to improve fitness and performance. To compare reaction time, stability performance capacity, and strength performance capacity of élite racing drivers with those of age-matched, physically active controls. Eight élite racing drivers and 10 physically active controls matched for age and weight were tested in a reaction and determination test requiring upper and lower extremity responses to visual and audio cues. Further tests comprised evaluation of one-leg postural stability on a two-dimensional moveable platform, measures of maximum strength performance capacity of the extensors of the leg on a leg press, and a test of force capacity of the arms in a sitting position at a steering wheel. An additional arm endurance test consisted of isometric work at the steering wheel at +30 degrees and -30 degrees where an eccentric threshold load of 30 N.m was applied. Subjects had to hold the end positions above this threshold until exhaustion. Univariate one way analysis of variance (alpha = 0.05) including a Bonferroni adjustment was used to detect group differences between the drivers and controls. The reaction time of the racing drivers was significantly faster than the controls (p = 0.004). The following motor reaction time and reaction times in the multiple determination test did not differ between the groups. No significant differences (p>0.05) were found for postural stability, leg extensor strength, or arm strength and endurance. Racing drivers have faster reaction times than age-matched physically active controls. Further development of motor sport-specific test protocols is suggested. According to the requirements of motor racing, strength and sensorimotor performance capacity can potentially be improved.

Body Mass and Circumference of Upper Arm Are Associated with Race Performance in Ultraendurance Runners in a Multistage Race--The Isarrun 2006

ERIC Educational Resources Information Center

Knechtle, Beat; Duff, Brida; Welzel, Ulrich; Kohler, Gotz

2009-01-01

In the present study, we investigated the association of anthropometric parameters with race performance in ultraendurance runners in a multistage ultraendurance run, in which athletes had to run 338 km within 5 consecutive days. In 17 male successful finishers, calculations of body mass, body height, skinfold thicknesses, extremity circumference,…

Co-evolution in a landrace meta-population: two closely related pathogens interacting with the same host can lead to different adaptive outcomes

PubMed Central

Rau, Domenico; Rodriguez, Monica; Leonarda Murgia, Maria; Balmas, Virgilio; Bitocchi, Elena; Bellucci, Elisa; Nanni, Laura; Attene, Giovanna; Papa, Roberto

2015-01-01

We examined the local adaptation patterns in a system comprising several interconnected heterogeneous plant populations from which populations of two phylogenetically closely related pathogens were also sampled. The host is Hordeum vulgare (cultivated barley); the pathogens are Pyrenophora teres f. teres (net form) and Pyrenophora teres f. maculata (spot form), the causal agents of barley net blotch. We integrated two approaches, the comparison between the population structures of the host and the pathogens, and a cross-inoculation test. We demonstrated that two closely related pathogens with very similar niche specialisation and life-styles can give rise to different co-evolutionary outcomes on the same host. Indeed, we detected local adaptation for the net form of the pathogen but not for the spot form. We also provided evidence that an a-priori well-known resistance quantitative-trait-locus on barley chromosome 6H is involved in the co-evolutionary ‘arms race’ between the plant and the net-form pathogen. Moreover, data suggested latitudinal clines of host resistance and that different ecological conditions can result in differential selective pressures at different sites. Our data are of interest for on-farm conservation of plant genetic resources, as also in establishing efficient breeding programs and strategies for deployment of resistance genes of P. teres. PMID:26248796

On Reciprocal Causation in the Evolutionary Process.

PubMed

Svensson, Erik I

2018-01-01

Recent calls for a revision of standard evolutionary theory (SET) are based partly on arguments about the reciprocal causation. Reciprocal causation means that cause-effect relationships are bi-directional, as a cause could later become an effect and vice versa. Such dynamic cause-effect relationships raise questions about the distinction between proximate and ultimate causes, as originally formulated by Ernst Mayr. They have also motivated some biologists and philosophers to argue for an Extended Evolutionary Synthesis (EES). The EES will supposedly expand the scope of the Modern Synthesis (MS) and SET, which has been characterized as gene-centred, relying primarily on natural selection and largely neglecting reciprocal causation. Here, I critically examine these claims, with a special focus on the last conjecture. I conclude that reciprocal causation has long been recognized as important by naturalists, ecologists and evolutionary biologists working in the in the MS tradition, although it it could be explored even further. Numerous empirical examples of reciprocal causation in the form of positive and negative feedback are now well known from both natural and laboratory systems. Reciprocal causation have also been explicitly incorporated in mathematical models of coevolutionary arms races, frequency-dependent selection, eco-evolutionary dynamics and sexual selection. Such dynamic feedback were already recognized by Richard Levins and Richard Lewontin in their bok The Dialectical Biologist . Reciprocal causation and dynamic feedback might also be one of the few contributions of dialectical thinking and Marxist philosophy in evolutionary theory. I discuss some promising empirical and analytical tools to study reciprocal causation and the implications for the EES. Finally, I briefly discuss how quantitative genetics can be adapated to studies of reciprocal causation, constructive inheritance and phenotypic plasticity and suggest that the flexibility of this approach might have been underestimated by critics of contemporary evolutionary biology.

Genetic architecture of a feeding adaptation: garter snake (Thamnophis) resistance to tetrodotoxin bearing prey.

PubMed

Feldman, Chris R; Brodie, Edmund D; Brodie, Edmund D; Pfrender, Michael E

2010-11-07

Detailing the genetic basis of adaptive variation in natural populations is a first step towards understanding the process of adaptive evolution, yet few ecologically relevant traits have been characterized at the genetic level in wild populations. Traits that mediate coevolutionary interactions between species are ideal for studying adaptation because of the intensity of selection and the well-characterized ecological context. We have previously described the ecological context, evolutionary history and partial genetic basis of tetrodotoxin (TTX) resistance in garter snakes (Thamnophis). Derived mutations in a voltage-gated sodium channel gene (Na(v)1.4) in three garter snake species are associated with resistance to TTX, the lethal neurotoxin found in their newt prey (Taricha). Here we evaluate the contribution of Na(v)1.4 alleles to TTX resistance in two of those species from central coastal California. We measured the phenotypes (TTX resistance) and genotypes (Na(v)1.4 and microsatellites) in a local sample of Thamnophis atratus and Thamnophis sirtalis. Allelic variation in Na(v)1.4 explains 23 per cent of the variation in TTX resistance in T. atratus while variation in a haphazard sample of the genome (neutral microsatellite markers) shows no association with the phenotype. Similarly, allelic variation in Na(v)1.4 correlates almost perfectly with TTX resistance in T. sirtalis, but neutral variation does not. These strong correlations suggest that Na(v)1.4 is a major effect locus. The simple genetic architecture of TTX resistance in garter snakes may significantly impact the dynamics of phenotypic coevolution. Fixation of a few alleles of major effect in some garter snake populations may have led to the evolution of extreme phenotypes and an 'escape' from the arms race with newts.

Historical Contingency in a Multigene Family Facilitates Adaptive Evolution of Toxin Resistance.

PubMed

McGlothlin, Joel W; Kobiela, Megan E; Feldman, Chris R; Castoe, Todd A; Geffeney, Shana L; Hanifin, Charles T; Toledo, Gabriela; Vonk, Freek J; Richardson, Michael K; Brodie, Edmund D; Pfrender, Michael E; Brodie, Edmund D

2016-06-20

Novel adaptations must originate and function within an already established genome [1]. As a result, the ability of a species to adapt to new environmental challenges is predicted to be highly contingent on the evolutionary history of its lineage [2-6]. Despite a growing appreciation of the importance of historical contingency in the adaptive evolution of single proteins [7-11], we know surprisingly little about its role in shaping complex adaptations that require evolutionary change in multiple genes. One such adaptation, extreme resistance to tetrodotoxin (TTX), has arisen in several species of snakes through coevolutionary arms races with toxic amphibian prey, which select for TTX-resistant voltage-gated sodium channels (Nav) [12-16]. Here, we show that the relatively recent origins of extreme toxin resistance, which involve the skeletal muscle channel Nav1.4, were facilitated by ancient evolutionary changes in two other members of the same gene family. A substitution conferring TTX resistance to Nav1.7, a channel found in small peripheral neurons, arose in lizards ∼170 million years ago (mya) and was present in the common ancestor of all snakes. A second channel found in larger myelinated neurons, Nav1.6, subsequently evolved resistance in four different snake lineages beginning ∼38 mya. Extreme TTX resistance has evolved at least five times within the past 12 million years via changes in Nav1.4, but only within lineages that previously evolved resistant Nav1.6 and Nav1.7. Our results show that adaptive protein evolution may be contingent upon enabling substitutions elsewhere in the genome, in this case, in paralogs of the same gene family. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effects of recombination, mutation and selection on the evolution of the Rp1 resistance genes in grasses.

PubMed

Jouet, Agathe; McMullan, Mark; van Oosterhout, Cock

2015-06-01

Plant immune genes, or resistance genes, are involved in a co-evolutionary arms race with a diverse range of pathogens. In agronomically important grasses, such R genes have been extensively studied because of their role in pathogen resistance and in the breeding of resistant cultivars. In this study, we evaluate the importance of recombination, mutation and selection on the evolution of the R gene complex Rp1 of Sorghum, Triticum, Brachypodium, Oryza and Zea. Analyses show that recombination is widespread, and we detected 73 independent instances of sequence exchange, involving on average 1567 of 4692 nucleotides analysed (33.4%). We were able to date 24 interspecific recombination events and found that four occurred postspeciation, which suggests that genetic introgression took place between different grass species. Other interspecific events seemed to have been maintained over long evolutionary time, suggesting the presence of balancing selection. Significant positive selection (i.e. a relative excess of nonsynonymous substitutions (dN /dS >1)) was detected in 17-95 codons (0.42-2.02%). Recombination was significantly associated with areas with high levels of polymorphism but not with an elevated dN /dS ratio. Finally, phylogenetic analyses show that recombination results in a general overestimation of the divergence time (mean = 14.3%) and an alteration of the gene tree topology if the tree is not calibrated. Given that the statistical power to detect recombination is determined by the level of polymorphism of the amplicon as well as the number of sequences analysed, it is likely that many studies have underestimated the importance of recombination relative to the mutation rate. © 2015 John Wiley & Sons Ltd.

Evolution of the CRISPR-Cas adaptive immunity systems in prokaryotes: models and observations on virus-host coevolution.

PubMed

Koonin, Eugene V; Wolf, Yuri I

2015-01-01

CRISPR-Cas is an adaptive immunity system in prokaryotes that functions via a unique mechanism which involves incorporation of foreign DNA fragments into CRISPR arrays and subsequent utilization of transcripts of these inserts (known as spacers) as guide RNAs to cleave the cognate selfish element genome. Multiple attempts have been undertaken to explore the coevolution of viruses and microbial hosts carrying CRISPR-Cas using mathematical models that employ either systems of differential equations or an agent-based approach, or combinations thereof. Analysis of these models reveals highly complex co-evolutionary dynamics that ensues from the combination of the heritability of the CRISPR-mediated adaptive immunity with the existence of different degrees of immunity depending on the number of cognate spacers and the cost of carrying a CRISPR-Cas locus. Depending on the details of the models, a variety of testable, sometimes conflicting predictions have been made on the dependence of the degree of immunity and the benefit of maintaining CRISPR-Cas on the abundance and diversity of hosts and viruses. Some of these predictions have already been directly validated experimentally. In particular, both the reality of the virus-host arms race, with viruses escaping resistance and hosts reacquiring it through the capture of new spacers, and the fitness cost of CRISPR-Cas due to the curtailment of beneficial HGT have been reproduced in the laboratory. However, to test the predictions of the models more specifically, detailed studies of coevolving populations of microbes and viruses both in nature and in the laboratory are essential. Such analyses are expected to yield disagreements with the predictions of the current, oversimplified models and to trigger a new round of theoretical developments.

"European" race-specific metacentrics in East Siberian common shrews (Sorex araneus): a description of two new chromosomal races, Irkutsk and Zima.

PubMed

Pavlova, Svetlana V; Borisov, Sergei A; Timoshenko, Alexander F; Sheftel, Boris I

2017-01-01

Karyotype studies of common shrews in the vicinity of Lake Baikal (Irkutsk Region, Eastern Siberia) resulted in the description of two new chromosomal races of Sorex araneus Linnaeus, 1758 (Lypotyphla, Mammalia), additional to 5 races formerly found in Siberia. In the karyotypes of 12 specimens from 3 locations, the polymorphism of metacentric and acrocentric chromosomes of the Robertsonian type was recorded and two distinct groups of karyotypes interpreted as the chromosomal races were revealed. They are geographically distant and described under the racial names Irkutsk (Ir) and Zima (Zi). Karyotypes of both races were characterized by species-specific (the same for all 74 races known so far) metacentric autosomes af, bc, tu and jl , and the typical sex chromosome system - XX/XY 1 Y 2 . The race-specific arm chromosome combinations include three metacentrics and four acrocentrics in the Irkutsk race ( gk, hi, nq, m, o, p, r ) and four metacentrics and two acrocentrics in the Zima race ( gm, hi, ko, nq, p, r ). Within the races, individuals with polymorphic chromosomes were detected ( g/m, k/o, n/q, p/r ). The presence of the specific metacentric gk allowed us to include the Irkutsk race into the Siberian Karyotypic Group (SKG), distributed in surrounding regions. The Zima race karyotype contained two metacentrics, gm and ko , which have been never found in the Siberian part of the species range, but appear as the common feature of chromosomal races belonging to the West European Karyotypic Group (WEKG). Moreover, the metacentrics of that karyotype are almost identical to the Åkarp race (except the heterozygous pair p/r ) locally found in the southern Sweden. One of two Siberian races described here for the first time, the Zima race, occurs in an area considerably distant from Europe and shares the common metacentrics ( gm, hi, ko ) with races included in WEKG. This fact may support a hypothesis of independent formation of identical arm chromosome combinations due to occurrence of the same centric fusions in different parts of the species range.

Bibliography of Nuclear Education Resources.

ERIC Educational Resources Information Center

Alexander, Susan, Ed.

Provided in this bibliography is a listing of nuclear education books and resource materials. Entries (most of which are annotated) are presented under these headings: action; arms control and negotiations; arms race; the arts; atomic energy; atomic testing; bibliographies; civil defense; conference proceedings; conflict solving; conversion;…

Urinary tract infection: recent insight into the evolutionary arms race between uropathogenic Escherichia coli and our immune system.

PubMed

Schwab, Sebastian; Jobin, Katarzyna; Kurts, Christian

2017-12-01

Urinary tract infections (UTIs) are among the most common bacterial infections worldwide. Humans evolved various immune-dependent and independent defense mechanisms, while pathogens evolved multiple virulence factors to fight back. This article summarizes recent findings regarding the arms race between hosts and pathogens in UTIs. It was recently reported that macrophage subsets regulate neutrophil-mediated defense in primary UTIs but seem to subvert adaptive immunity upon re-infection. Moreover, some bacterial strains can survive inside macrophages, leading to recurrent infections. Inflammasome activation results in infected host cell death and pathogen release, facilitating the removal of intracellular bacteria. As a counteraction, some bacteria evolved mechanisms to disrupt inflammasome activation. Mucosal-associated invariant T cells are further effectors that can lyse infected epithelial cells and release intracellular bacteria. Once released, the bacteria are phagocytosed by neutrophils. However, some bacteria can inhibit neutrophil migration and deprive neutrophils of nutrients. Furthermore, the complement system, considered generally bactericidal, is exploited by the bacteria for cellular invasion. Another weapon against UTI is antimicrobial peptides, e.g. ribonuclease 7, but its production is inhibited by certain bacterial strains. Thus the arms race in UTI is ongoing, and knowing the enemy's methods can help in developing new drugs to win the race. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

The Advanced Placement Arms Race and the Reproduction of Educational Inequality

ERIC Educational Resources Information Center

Klugman, Joshua

2013-01-01

Background: Access to Advanced Placement (AP) courses is stratified by class and race. Researchers have identified how schools serving disadvantaged students suffer from various kinds of resource deprivations, concluding that interventions are needed to equalize access to AP courses. On the other hand, the theory of Effectively Maintained…

Changes in hospital competitive strategy: a new medical arms race?

PubMed

Devers, Kelly J; Brewster, Linda R; Casalino, Lawrence P

2003-02-01

To describe changes in hospitals' competitive strategies, specifically the relative emphasis placed on strategies for competing along price and nonprice (i.e., service, amenities, perceived quality) dimensions, and the reasons for any observed shifts. This study uses data gathered through the Community Tracking Study site visits, a longitudinal study of a nationally representative sample of 12 U.S. communities. Research teams visited each of these communities every two years since 1996 and conducted between 50 to 90 semistructured interviews. Additional information on hospital competition and strategy was gathered from secondary data. We found that hospitals' strategic emphasis changed significantly between 1996-1997 and 2000-2001. In the mid-1990s, hospitals primarily competed on price through "wholesale" strategies (i.e., providing services attractive to managed care plans). By 2000-2001, nonprice competition was becoming increasingly important and hospitals were reviving "retail" strategies (i.e., providing services attractive to individual physicians and the patients they serve). Three major factors explain this shift in hospital strategy: less than anticipated selective contracting and capitated payment; the freeing up of hospital resources previously devoted to horizontal and vertical integration strategies; and, the emergence and growth of new competitors. Renewed emphasis on nonprice competition and retail strategies, and the service mimicking and one-upmanship that result, suggest that a new medical arms race is emerging. However, there are important differences between the medical arms race today and the one that occurred in the 1970s and early 1980s: the hospital market is more concentrated and price competition remains relatively important. The development of a new medical arms race has significant research and policy implications.

Changes in Hospital Competitive Strategy: A New Medical Arms Race?

PubMed Central

Devers, Kelly J; Brewster, Linda R; Casalino, Lawrence P

2003-01-01

Objective To describe changes in hospitals' competitive strategies, specifically the relative emphasis placed on strategies for competing along price and nonprice (i.e., service, amenities, perceived quality) dimensions, and the reasons for any observed shifts. Methods This study uses data gathered through the Community Tracking Study site visits, a longitudinal study of a nationally representative sample of 12 U.S. communities. Research teams visited each of these communities every two years since 1996 and conducted between 50 to 90 semistructured interviews. Additional information on hospital competition and strategy was gathered from secondary data. Principal Findings We found that hospitals' strategic emphasis changed significantly between 1996–1997 and 2000–2001. In the mid-1990s, hospitals primarily competed on price through “wholesale” strategies (i.e., providing services attractive to managed care plans). By 2000–2001, nonprice competition was becoming increasingly important and hospitals were reviving “retail” strategies (i.e., providing services attractive to individual physicians and the patients they serve). Three major factors explain this shift in hospital strategy: less than anticipated selective contracting and capitated payment; the freeing up of hospital resources previously devoted to horizontal and vertical integration strategies; and, the emergence and growth of new competitors. Conclusion Renewed emphasis on nonprice competition and retail strategies, and the service mimicking and one-upmanship that result, suggest that a new medical arms race is emerging. However, there are important differences between the medical arms race today and the one that occurred in the 1970s and early 1980s: the hospital market is more concentrated and price competition remains relatively important. The development of a new medical arms race has significant research and policy implications. PMID:12650375

Ballistic missile defense technologies

NASA Astrophysics Data System (ADS)

1985-09-01

A report on Ballistic Missile Technologies includes the following: Executive summary; Introduction; Ballistic missiles then and now; Deterrence, U.S. nuclear strategy, and BMD; BMD capabilities and the strategic balance; Crisis stability, arms race stability, and arms control issues; Ballistic missile defense technologies; Feasibility; Alternative future scenarios; Alternative R&D programs.

Worldwide Report, Arms Control

DTIC Science & Technology

1985-12-19

disarmament shows that the decisive factor in Soviet-U.S. relations remains the sphere of security, the core of which is the organically linked ...actiye in the United States for whom the very prospect of preconditions for curbing the arms race is patently not to their linking . Certain quarters in...distorting the essence of the issue of the organic link between preventing the mili- tarization of space and the reduction of nuclear arms on earth

Cuckoos and parasitic ants: Interspecific brood parasitism as an evolutionary arms race.

PubMed

Davies, N B; Bourke, A F; de L Brooke, M

1989-09-01

Each summer thousands of nesting birds feed cuckoo chicks that have killed the hosts' own young. Likewise, worker ants rear the brood of other ants that have killed the workers' queen or even induced the workers to kill their queen themselves. In both cases the hosts spend time and energy raising offspring that, to them, are of no genetic value. Such exploitation involves intricate parasitic adaptations for deceiving hosts. It should also provoke host defences. Brood and social parasites and their hosts therefore provide excellent opportunities for the study of evolutionary arms races. Copyright © 1989. Published by Elsevier Ltd.

Arms races and the evolution of big fierce societies.

PubMed

Boswell, G P; Franks, N R; Britton, N F

2001-08-22

The causes of biological gigantism have received much attention, but only for individual organisms. What selection pressures might favour the evolution of gigantic societies? Here we consider the largest single-queen insect societies, those of the Old World army ant Dorylus, single colonies of which can have 20 million workers. We propose that colony gigantism in Dorylus arises as a result of an arms race and test this prediction by developing a size-structured mathematical model. We use this model for exploring and potentially explaining differences in colony size, colony aggression and colony propagation strategies in populations of New World army ants Eciton and Old World army ants Dorylus. The model shows that, by determining evolutionarily stable strategies (ESSs), differences in the trophic levels at which these army ants live feed forwards into differences in their densities and collision rates and, hence, into different strategies of growth, aggression and propagation. The model predicts large colony size and the occurrence of battles and a colony-propagation strategy involving highly asymmetrical divisions in Dorylus and that Eciton colonies should be smaller, non-combative and exhibit equitable binary fission. These ESSs are in excellent agreement with field observations and demonstrate that gargantuan societies can arise through arms races.

The U.S. Needs a Coherent Space Policy.

ERIC Educational Resources Information Center

Pressler, Larry

1983-01-01

Despite the possibility that efforts to prevent an arms race in space between the United States and the Soviet Union might fail, a serious attempt should be made to develop an arms control agreement because of the great risks of war in space and the expense of developing new weapons. (IS)

The Origins of the Cold War.

ERIC Educational Resources Information Center

Paterson, Thomas G.

1986-01-01

Briefly reviews conventional reasoning about the start of the Cold War. Describes contemporary revisionist views of the Cold War and the reasons they arose. Maintains that American leaders exaggerated the Soviet ideological and military threat, spurring an American arms build-up which ultimately led to the present-day arms race. (JDH)

Functional anatomy and muscle moment arms of the pelvic limb of an elite sprinting athlete: the racing greyhound (Canis familiaris)

PubMed Central

Williams, S B; Wilson, A M; Rhodes, L; Andrews, J; Payne, R C

2008-01-01

We provide quantitative anatomical data on the muscle–tendon architecture and geometry of the pelvic limb of an elite sprint athlete, the racing greyhound. Specifically, muscle masses, muscle lengths, fascicle lengths, pennation angles and muscle moment arms were measured. Maximum isometric force and power of muscles, the maximum muscle torque at joints and tendon stress and strain were estimated. We compare data with that published for a generalized breed of canid, and other cursorial mammals such as the horse and hare. The pelvic limb of the racing greyhound had a relatively large volume of hip extensor muscle, which is likely to be required for power production. Per unit body mass, some pelvic limb muscles were relatively larger than those in less specialized canines, and many hip extensor muscles had longer fascicle lengths. It was estimated that substantial extensor moments could be created about the tarsus and hip of the greyhound allowing high power output and potential for rapid acceleration. The racing greyhound hence possesses substantial specializations for enhanced sprint performance. PMID:18657259

Functional anatomy and muscle moment arms of the pelvic limb of an elite sprinting athlete: the racing greyhound (Canis familiaris).

PubMed

Williams, S B; Wilson, A M; Rhodes, L; Andrews, J; Payne, R C

2008-10-01

We provide quantitative anatomical data on the muscle-tendon architecture and geometry of the pelvic limb of an elite sprint athlete, the racing greyhound. Specifically, muscle masses, muscle lengths, fascicle lengths, pennation angles and muscle moment arms were measured. Maximum isometric force and power of muscles, the maximum muscle torque at joints and tendon stress and strain were estimated. We compare data with that published for a generalized breed of canid, and other cursorial mammals such as the horse and hare. The pelvic limb of the racing greyhound had a relatively large volume of hip extensor muscle, which is likely to be required for power production. Per unit body mass, some pelvic limb muscles were relatively larger than those in less specialized canines, and many hip extensor muscles had longer fascicle lengths. It was estimated that substantial extensor moments could be created about the tarsus and hip of the greyhound allowing high power output and potential for rapid acceleration. The racing greyhound hence possesses substantial specializations for enhanced sprint performance.

Mapping and characterization of wheat stem rust resistance genes SrTm5 and Sr60 from Triticum monococcum.

PubMed

Chen, Shisheng; Guo, Yan; Briggs, Jordan; Dubach, Felix; Chao, Shiaoman; Zhang, Wenjun; Rouse, Matthew N; Dubcovsky, Jorge

2018-03-01

The new stem rust resistance gene Sr60 was fine-mapped to the distal region of chromosome arm 5A m S, and the TTKSK-effective gene SrTm5 could be a new allele of Sr22. The emergence and spread of new virulent races of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici; Pgt), including the Ug99 race group, is a serious threat to global wheat production. In this study, we mapped and characterized two stem rust resistance genes from diploid wheat Triticum monococcum accession PI 306540. We mapped SrTm5, a previously postulated gene effective to Ug99, on chromosome arm 7A m L, completely linked to Sr22. SrTm5 displayed a different race specificity compared to Sr22 indicating that they are distinct. Sequencing of the Sr22 homolog in PI 306540 revealed a novel haplotype. Characterization of the segregating populations with Pgt race QFCSC revealed an additional resistance gene on chromosome arm 5A m S that was assigned the official name Sr60. This gene was also effective against races QTHJC and SCCSC but not against TTKSK (a Ug99 group race). Using two large mapping populations (4046 gametes), we mapped Sr60 within a 0.44 cM interval flanked by sequenced-based markers GH724575 and CJ942731. These two markers delimit a 54.6-kb region in Brachypodium distachyon chromosome 4 and a 430-kb region in the Chinese Spring reference genome. Both regions include a leucine-rich repeat protein kinase (LRRK123.1) that represents a potential candidate gene. Three CC-NBS-LRR genes were found in the colinear Brachypodium region but not in the wheat genome. We are currently developing a Bacterial Artificial Chromosome library of PI 306540 to determine which of these candidate genes are present in the T. monococcum genome and to complete the cloning of Sr60.

Introducing TreeCollapse: a novel greedy algorithm to solve the cophylogeny reconstruction problem.

PubMed

Drinkwater, Benjamin; Charleston, Michael A

2014-01-01

Cophylogeny mapping is used to uncover deep coevolutionary associations between two or more phylogenetic histories at a macro coevolutionary scale. As cophylogeny mapping is NP-Hard, this technique relies heavily on heuristics to solve all but the most trivial cases. One notable approach utilises a metaheuristic to search only a subset of the exponential number of fixed node orderings possible for the phylogenetic histories in question. This is of particular interest as it is the only known heuristic that guarantees biologically feasible solutions. This has enabled research to focus on larger coevolutionary systems, such as coevolutionary associations between figs and their pollinator wasps, including over 200 taxa. Although able to converge on solutions for problem instances of this size, a reduction from the current cubic running time is required to handle larger systems, such as Wolbachia and their insect hosts. Rather than solving this underlying problem optimally this work presents a greedy algorithm called TreeCollapse, which uses common topological patterns to recover an approximation of the coevolutionary history where the internal node ordering is fixed. This approach offers a significant speed-up compared to previous methods, running in linear time. This algorithm has been applied to over 100 well-known coevolutionary systems converging on Pareto optimal solutions in over 68% of test cases, even where in some cases the Pareto optimal solution has not previously been recoverable. Further, while TreeCollapse applies a local search technique, it can guarantee solutions are biologically feasible, making this the fastest method that can provide such a guarantee. As a result, we argue that the newly proposed algorithm is a valuable addition to the field of coevolutionary research. Not only does it offer a significantly faster method to estimate the cost of cophylogeny mappings but by using this approach, in conjunction with existing heuristics, it can assist in recovering a larger subset of the Pareto front than has previously been possible.

Coevolutionary constraints in the sequence-space of macromolecular complexes reflect their self-assembly pathways.

PubMed

Mallik, Saurav; Kundu, Sudip

2017-07-01

Is the order in which biomolecular subunits self-assemble into functional macromolecular complexes imprinted in their sequence-space? Here, we demonstrate that the temporal order of macromolecular complex self-assembly can be efficiently captured using the landscape of residue-level coevolutionary constraints. This predictive power of coevolutionary constraints is irrespective of the structural, functional, and phylogenetic classification of the complex and of the stoichiometry and quaternary arrangement of the constituent monomers. Combining this result with a number of structural attributes estimated from the crystal structure data, we find indications that stronger coevolutionary constraints at interfaces formed early in the assembly hierarchy probably promotes coordinated fixation of mutations that leads to high-affinity binding with higher surface area, increased surface complementarity and elevated number of molecular contacts, compared to those that form late in the assembly. Proteins 2017; 85:1183-1189. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Sanity, Science, and Survival: A Conservation with Marvin L. Goldberger.

ERIC Educational Resources Information Center

Davidson, Mark

1985-01-01

The president of the California Institute of Technology speaks out against the arms race. He discusses worthwhile scientific-technological projects that could be pursued with money presently used for weapons. There are no technical solutions to arms control issues. The solution depends upon a change of human attitude. Education's role is…

Options for US National Strategy in the 1980’s and Beyond.

DTIC Science & Technology

1981-01-09

34plausible environmental possibilities" (see Figure 1). Bipolar Tripolar Multipolar World Order Power US versus US/USSR/PRC Rise of 3d Relative Alignments...constrained. 8 t~ Arms limitation agreements would break down and the arms race would resume. The tripolar environment envisions a world in which the power

United Campuses to Prevent Nuclear War: Nuclear War Course Summaries.

ERIC Educational Resources Information Center

Journal of College Science Teaching, 1983

1983-01-01

Briefly describes 46 courses on nuclear war available from United Campuses to Prevent Nuclear War (UCAM). These courses are currently being or have been taught at colleges/universities, addressing effects of nuclear war, arms race history, new weapons, and past arms control efforts. Syllabi (with assignments/reading lists) are available from UCAM.…

From Travis to Today: An Analysis Of Racial Progress in the Us Air Force Officer Corps Since 1971

DTIC Science & Technology

2009-04-01

Over Who Have Completed High School or College, by Race, Hispanic Origin and Sex : Selected Years 1940 to 2007,” http://www.census.gov/population/www...and Over Who Have Completed High School or College, by Race, Hispanic Origin and Sex : Selected Years 1940 to 2007,” http://www.census.gov/population...of Defense, Career Progression of Minority and Women Officers, ix. 38 Dorn, Edwin, Who Defends America? Race, Sex , and Class in the Armed Forces

Past Informing Present: Parallels Between Racial Integration in the Armed Forces and Repeal of Don’t Ask, Don’t Tell

DTIC Science & Technology

2011-02-15

Military (pp. 121- 133). New York, New York: Aldine de Gruyter. Schiefer, M. (2010, October 21). Email Correspondence: Race on OSB . San Antonio TX...M. (2010, October 21). Email Correspondence: Race on OSB . San Antonio TX. 73 Military Leadership Diversity Commission. (n.d.). Recent Enlisted

Counteracting Power Analysis Attacks by Masking

NASA Astrophysics Data System (ADS)

Oswald, Elisabeth; Mangard, Stefan

The publication of power analysis attacks [12] has triggered a lot of research activities. On the one hand these activities have been dedicated toward the development of secure and efficient countermeasures. On the other hand also new and improved attacks have been developed. In fact, there has been a continuous arms race between designers of countermeasures and attackers. This chapter provides a brief overview of the state-of-the art in the arms race in the context of a countermeasure called masking. Masking is a popular countermeasure that has been extensively discussed in the scientific community. Numerous articles have been published that explain different types of masking and that analyze weaknesses of this countermeasure.

The Atomic Papers: A citizen's guide to selected books and articles on the bomb, the arms race, nuclear power, the peace movement, and related issues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, G.

The Atomic Papers annotates over 800 books published since 1945 and approximately 300 periodical articles since 1980 on every facet of the nuclear dilemma: the development and effects of the bomb, the arms race, nuclear proliferation, and the peace movement. Work on both sides of the nuclear power controversy also receives substantial attention. All references are to English-language material, and nearly half are to work published since 1980. The concluding chapter, ''The Art of Fission,'' describes over one hundred novels and stories with nuclear themes published since 1945--and, in a few cases, before that date.

Psychosocial Aspects of Nuclear Developments. Task Force Report 20.

ERIC Educational Resources Information Center

American Psychiatric Association, Washington, DC.

This is the report of a task force formed to bring psychological understanding to bear on the various aspects of the development of nuclear arms and nuclear energy and the threat they pose to human physical, mental, and emotional health. The first of seven articles considers the sociopsychological aspects of the nuclear arms race. Other articles…

A new 2DS·2RL Robertsonian translocation transfers stem rust resistance gene Sr59 into wheat.

PubMed

Rahmatov, Mahbubjon; Rouse, Matthew N; Nirmala, Jayaveeramuthu; Danilova, Tatiana; Friebe, Bernd; Steffenson, Brian J; Johansson, Eva

2016-07-01

A new stem rust resistance gene Sr59 from Secale cereale was introgressed into wheat as a 2DS·2RL Robertsonian translocation. Emerging new races of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici), from Africa threaten global wheat (Triticum aestivum L.) production. To broaden the resistance spectrum of wheat to these widely virulent African races, additional resistance genes must be identified from all possible gene pools. From the screening of a collection of wheat-rye (Secale cereale L.) chromosome substitution lines developed at the Swedish University of Agricultural Sciences, we described the line 'SLU238' 2R (2D) as possessing resistance to many races of P. graminis f. sp. tritici, including the widely virulent race TTKSK (isolate synonym Ug99) from Africa. The breakage-fusion mechanism of univalent chromosomes was used to produce a new Robertsonian translocation: T2DS·2RL. Molecular marker analysis and stem rust seedling assays at multiple generations confirmed that the stem rust resistance from 'SLU238' is present on the rye chromosome arm 2RL. Line TA5094 (#101) was derived from 'SLU238' and was found to be homozygous for the T2DS·2RL translocation. The stem rust resistance gene on chromosome 2RL arm was designated as Sr59. Although introgressions of rye chromosome arms into wheat have most often been facilitated by irradiation, this study highlights the utility of the breakage-fusion mechanism for rye chromatin introgression. Sr59 provides an additional asset for wheat improvement to mitigate yield losses caused by stem rust.

A History of the Huntsville Division U.S. Army Corps of Engineers 15 October 1967 - 31 December 1976

DTIC Science & Technology

1978-09-06

discriminate between decoys and armed warheads until the slowing effect of denser air in the lower atmosphere had helped sort out heavy projectiles...would have to keep up by enlarging her forces, and the arms race would be accelerated at the expense of detente. The knowledgeable called this "the...perhaps because of Vietnam, the Soviets showed themselves reluctant to talk about arms limitations in general and BMD in particular, despite

A new derived and highly polymorphic chromosomal race of Liolaemus monticola (Iguanidae) from the 'Norte Chico' of Chile.

PubMed

Lamborot, M

1998-06-01

A multiple Robertsonian fission chromosomal race of the Liolaemus monticola complex in Chile is described and is shown to be the most derived and the most complex among the Liolaemus examined thus far. The 29 karyotyped lizards analysed from the locality of Mina Hierro Viejo, Petorca, Provincia de Valparaiso, Chile, exhibited a diploid chromosomal number ranging from 42 to 44, and several polymorphisms. The polymorphisms included: a pair 1 fission; a pair 2 fission plus a pericentric inversion in one of the fission products, which moved the NOR and satellite from the tip of the long arm of the metacentric 2 to the short arm of the fission product; a fission in pair 3; a polymorphism for an enlarged chromosome pair 6; and a polymorphism for a pericentric inversion in pair 7. This population is fixed for a fission of chromosome pair 4. A total of 76% of the lizards analysed were polymorphic for one or more pairs of chromosomes. We have compared these data with other Liolaemus monticola chromosomal races and calculated the Hardy-Weinberg ratios for the polymorphic chromosome pairs in this Multiple-Fission race. Karyotypic differences between the Northern (2n = 38-40) and the Multiple-Fission (2n = 42-44) races were attributed mainly to Robertsonian fissions, an enlarged chromosome and pericentric inversions involving the macrochromosomes and one microchromosome pair.

A Short Guide to U.S. Arms Control Policy.

ERIC Educational Resources Information Center

Howard, Norman, Ed.; Sussman, Colleen, Ed.

Steps the United States is taking to lessen the danger of war while building international confidence and security are described. The commitment of the United States to arms control is based on the conviction that the United States and the Soviet Union have a common interest in the avoidance of nuclear war and the survival of the human race. A…

Phylogenetic framework for coevolutionary studies: a compass for exploring jungles of tangled trees.

PubMed

Martínez-Aquino, Andrés

2016-08-01

Phylogenetics is used to detect past evolutionary events, from how species originated to how their ecological interactions with other species arose, which can mirror cophylogenetic patterns. Cophylogenetic reconstructions uncover past ecological relationships between taxa through inferred coevolutionary events on trees, for example, codivergence, duplication, host-switching, and loss. These events can be detected by cophylogenetic analyses based on nodes and the length and branching pattern of the phylogenetic trees of symbiotic associations, for example, host-parasite. In the past 2 decades, algorithms have been developed for cophylogetenic analyses and implemented in different software, for example, statistical congruence index and event-based methods. Based on the combination of these approaches, it is possible to integrate temporal information into cophylogenetical inference, such as estimates of lineage divergence times between 2 taxa, for example, hosts and parasites. Additionally, the advances in phylogenetic biogeography applying methods based on parametric process models and combined Bayesian approaches, can be useful for interpreting coevolutionary histories in a scenario of biogeographical area connectivity through time. This article briefly reviews the basics of parasitology and provides an overview of software packages in cophylogenetic methods. Thus, the objective here is to present a phylogenetic framework for coevolutionary studies, with special emphasis on groups of parasitic organisms. Researchers wishing to undertake phylogeny-based coevolutionary studies can use this review as a "compass" when "walking" through jungles of tangled phylogenetic trees.

Phylogenetic framework for coevolutionary studies: a compass for exploring jungles of tangled trees

PubMed Central

2016-01-01

Abstract Phylogenetics is used to detect past evolutionary events, from how species originated to how their ecological interactions with other species arose, which can mirror cophylogenetic patterns. Cophylogenetic reconstructions uncover past ecological relationships between taxa through inferred coevolutionary events on trees, for example, codivergence, duplication, host-switching, and loss. These events can be detected by cophylogenetic analyses based on nodes and the length and branching pattern of the phylogenetic trees of symbiotic associations, for example, host–parasite. In the past 2 decades, algorithms have been developed for cophylogetenic analyses and implemented in different software, for example, statistical congruence index and event-based methods. Based on the combination of these approaches, it is possible to integrate temporal information into cophylogenetical inference, such as estimates of lineage divergence times between 2 taxa, for example, hosts and parasites. Additionally, the advances in phylogenetic biogeography applying methods based on parametric process models and combined Bayesian approaches, can be useful for interpreting coevolutionary histories in a scenario of biogeographical area connectivity through time. This article briefly reviews the basics of parasitology and provides an overview of software packages in cophylogenetic methods. Thus, the objective here is to present a phylogenetic framework for coevolutionary studies, with special emphasis on groups of parasitic organisms. Researchers wishing to undertake phylogeny-based coevolutionary studies can use this review as a “compass” when “walking” through jungles of tangled phylogenetic trees. PMID:29491928

The Militarisation of English Schools: Troops to Teaching and the Implications for Initial Teacher Education and Race Equality

ERIC Educational Resources Information Center

Chadderton, Charlotte

2014-01-01

This article considers the implications of the Troops to Teaching (TtT) programme, to be introduced in England in autumn 2013, for Initial Teacher Education (ITE) and race equality. TtT will fast-track ex-armed service members to teach in schools, without necessarily the requirement of a university degree. Employing theories of white supremacy,…

The Domestic Arms Race.

ERIC Educational Resources Information Center

Caetano, Donald F.

1979-01-01

Discusses the relationship of familial influence, victimization, gun ownership, and attitudes toward gun control. Victims whose parents owned guns are much more likely to own guns and oppose legislation. (JMF)

Signatures of host specialization and a recent transposable element burst in the dynamic one-speed genome of the fungal barley powdery mildew pathogen.

PubMed

Frantzeskakis, Lamprinos; Kracher, Barbara; Kusch, Stefan; Yoshikawa-Maekawa, Makoto; Bauer, Saskia; Pedersen, Carsten; Spanu, Pietro D; Maekawa, Takaki; Schulze-Lefert, Paul; Panstruga, Ralph

2018-05-22

Powdery mildews are biotrophic pathogenic fungi infecting a number of economically important plants. The grass powdery mildew, Blumeria graminis, has become a model organism to study host specialization of obligate biotrophic fungal pathogens. We resolved the large-scale genomic architecture of B. graminis forma specialis hordei (Bgh) to explore the potential influence of its genome organization on the co-evolutionary process with its host plant, barley (Hordeum vulgare). The near-chromosome level assemblies of the Bgh reference isolate DH14 and one of the most diversified isolates, RACE1, enabled a comparative analysis of these haploid genomes, which are highly enriched with transposable elements (TEs). We found largely retained genome synteny and gene repertoires, yet detected copy number variation (CNV) of secretion signal peptide-containing protein-coding genes (SPs) and locally disrupted synteny blocks. Genes coding for sequence-related SPs are often locally clustered, but neither the SPs nor the TEs reside preferentially in genomic regions with unique features. Extended comparative analysis with different host-specific B. graminis formae speciales revealed the existence of a core suite of SPs, but also isolate-specific SP sets as well as congruence of SP CNV and phylogenetic relationship. We further detected evidence for a recent, lineage-specific expansion of TEs in the Bgh genome. The characteristics of the Bgh genome (largely retained synteny, CNV of SP genes, recently proliferated TEs and a lack of significant compartmentalization) are consistent with a "one-speed" genome that differs in its architecture and (co-)evolutionary pattern from the "two-speed" genomes reported for several other filamentous phytopathogens.

Soviet News and Propaganda Analysis Based on RED STAR (The Official Newspaper of the Soviet Defense Establishment) for the Period 1-30 November 1984. Volume 4, Number 11.

DTIC Science & Technology

1984-11-30

government. * Many innocent women and children are killed as a result of American sponsored military raids into Nicaragua. Fifty-six percent of Red...goals (in regard to the arms race): -- To gain a first-strike advantage. -- To double the number of nuclear weapons. -- To refuse to freeze arms...international issues/events. It addresses the issues important to the political elite.c-- .. Men and women in the Soviet armed forces receive political

Age, gender, and race/ethnic differences in total body and subregional bone density1

PubMed Central

Looker, Anne C; Melton, L. Joseph; Harris, Tamara; Borrud, Lori; Shepherd, John; McGowan, Joan

2011-01-01

Introduction Total body dual-energy x-ray absorptiometry (DXA) data offer the opportunity to compare bone density of demographic groups across the entire skeleton. Methods The present study uses total body DXA data (Hologic QDR 4500A, Hologic Inc, Bedford MA) from the National Health and Nutrition Examination Survey (NHANES) 1999–2004 to examine bone mineral density (BMD) of the total body and selected skeletal subregions in a wide age range of adult men and women from three race/ethnic groups. Total body, lumbar spine, pelvis, right leg, and left arm BMD and lean mass from 13,091 adults age 20 years and older were used. The subregions were chosen to represent sites with different degrees of weight bearing. Results Mean BMD varied in expected ways for some demographic characteristics (men>women and non-Hispanic blacks>non-Hispanic whites) but not others (non-Hispanic whites>Mexican Americans). Differences in age patterns in BMD also emerged for some characteristics (sex) but not others (race/ethnicity). Differences in cross-sectional age patterns in BMD and lean mass by degree of weight-bearing in older adults were observed for the pelvis, leg and arm. Conclusion This information may be useful for generating hypotheses about age, race, and sex differences in fracture risk in the population. PMID:19048179

Polymyalgia Rheumatica

MedlinePlus

... symptom) Aches or pain in your neck, upper arms, buttocks, hips or thighs Stiffness in affected areas, ... two times more likely to develop the disorder. Race and geographic region. Polymyalgia rheumatica is most common ...

Chest pain

MedlinePlus

... your jaw, left arm, or between your shoulder blades. You have nausea, dizziness, sweating, a racing heart, ... such as: Is the pain between the shoulder blades? Under the breast bone? Does the pain change ...

Adding the Fourth "R": A Systems Approach to Solving the Hacker's Arms Race

DOE Office of Scientific and Technical Information (OSTI.GOV)

Endicott-Popovsky, Barbara E.; Frincke, Deborah A.

2006-01-01

In this paper, the authors propose a modification of CERT's 3 R model to include a 4 th R, the discipline of Redress, identified as a necessary step to end the hacker arms race. Redress will require implementation of computer forensic investigation methods, tools and techniques that will permit evidence gathered to be admissible in a court of law, a standard not often understood or followed by many who are responsible for securing networks today. This leads the authors to conclude that there is a need for future work that will involve re-examination of the mechanisms and procedures used tomore » collect evidence of network intrusions in order to ensure that the Rules of Evidence requirements are considered.« less

Nuclear proliferation: Will the Soviet Union's collapse spawn a new arms race

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffin, R.D.

Almost 30 years ago, in the midst of the US-Soviet arms race, President John F. Kennedy warned of the danger of nuclear proliferation. Ironically, now that the Cold War is over, the prospect has become a reality. The collapse of the Soviet Union may have calmed fears of a nuclear Armageddon, but it has aroused new concerns about the spread of nuclear weapons. More than a dozen nations either have or are feverishly trying to develop nuclear arsenals, including Third World nations riven by religious and territorial disputes. If the world fails to contain the spread of nuclear-weapons technology, themore » balance of power that kept relative peace during the four decades of the Cold War may be displaced by a balance of terror.« less

Development of wheat-Aegilops speltoides recombinants and simple PCR-based markers for Sr32 and a new stem rust resistance gene on the 2S#1 chromosome.

PubMed

Mago, Rohit; Verlin, Dawn; Zhang, Peng; Bansal, Urmil; Bariana, Harbans; Jin, Yue; Ellis, Jeffrey; Hoxha, Sami; Dundas, Ian

2013-12-01

Wheat- Aegilops speltoides recombinants carrying stem rust resistance genes Sr32 and SrAes1t effective against Ug99 and PCR markers for marker-assisted selection. Wild relatives of wheat are important resources for new rust resistance genes but underutilized because the valuable resistances are often linked to negative traits that prevent deployment of these genes in commercial wheats. Here, we report ph1b-induced recombinants with reduced alien chromatin derived from E.R. Sears' wheat-Aegilops speltoides 2D-2S#1 translocation line C82.2, which carries the widely effective stem rust resistance gene Sr32. Infection type assessments of the recombinants showed that the original translocation in fact carries two stem rust resistance genes, Sr32 on the short arm and a previously undescribed gene SrAes1t on the long arm of chromosome 2S#1. Recombinants with substantially shortened alien chromatin were produced for both genes, which confer resistance to stem rust races in the TTKSK (Ug99) lineage and representative races of all Australian stem rust lineages. Selected recombinants were back crossed into adapted Australian cultivars and PCR markers were developed to facilitate the incorporation of these genes into future wheat varieties. Our recombinants and those from several other labs now show that Sr32, Sr39, and SrAes7t on the short arm and Sr47 and SrAes1t on the long arm of 2S#1 form two linkage groups and at present no rust races are described that can distinguish these resistance specificities.

Immune Receptors and Co-receptors in Antiviral Innate Immunity in Plants.

PubMed

Gouveia, Bianca C; Calil, Iara P; Machado, João Paulo B; Santos, Anésia A; Fontes, Elizabeth P B

2016-01-01

Plants respond to pathogens using an innate immune system that is broadly divided into PTI (pathogen-associated molecular pattern- or PAMP-triggered immunity) and ETI (effector-triggered immunity). PTI is activated upon perception of PAMPs, conserved motifs derived from pathogens, by surface membrane-anchored pattern recognition receptors (PRRs). To overcome this first line of defense, pathogens release into plant cells effectors that inhibit PTI and activate effector-triggered susceptibility (ETS). Counteracting this virulence strategy, plant cells synthesize intracellular resistance (R) proteins, which specifically recognize pathogen effectors or avirulence (Avr) factors and activate ETI. These coevolving pathogen virulence strategies and plant resistance mechanisms illustrate evolutionary arms race between pathogen and host, which is integrated into the zigzag model of plant innate immunity. Although antiviral immune concepts have been initially excluded from the zigzag model, recent studies have provided several lines of evidence substantiating the notion that plants deploy the innate immune system to fight viruses in a manner similar to that used for non-viral pathogens. First, most R proteins against viruses so far characterized share structural similarity with antibacterial and antifungal R gene products and elicit typical ETI-based immune responses. Second, virus-derived PAMPs may activate PTI-like responses through immune co-receptors of plant PTI. Finally, and even more compelling, a viral Avr factor that triggers ETI in resistant genotypes has recently been shown to act as a suppressor of PTI, integrating plant viruses into the co-evolutionary model of host-pathogen interactions, the zigzag model. In this review, we summarize these important progresses, focusing on the potential significance of antiviral immune receptors and co-receptors in plant antiviral innate immunity. In light of the innate immune system, we also discuss a newly uncovered layer of antiviral defense that is specific to plant DNA viruses and relies on transmembrane receptor-mediated translational suppression for defense.

Mating system and extra-pair paternity in the Fan-tailed Gerygone Gerygone flavolateralis in relation to parasitism by the Shining Bronze-cuckoo Chalcites lucidus

PubMed Central

Kuehn, Ralph; Gazda, Małgorzata A.; Sato, Nozomu J.; Okahisa, Yuji; Tanaka, Keita D.; Attisano, Alfredo; Gula, Roman; Ueda, Keisuke; Theuerkauf, Jörn

2018-01-01

Extra-pair copulation can increase genetic diversity and offspring fitness. However, it may also increase intra-nest variability in avian hosts of brood parasites, which can decrease the discrimination ability of host parents towards the parasite. In New Caledonia, the Fan-tailed Gerygone (Gerygone flavolateralis), which is parasitized by the Shining Bronze-cuckoo (Chalcites lucidus), has two nestling morphs, dark and bright, that can occur in monomorphic and polymorphic broods. Gerygone parents recognize and eject parasite nestlings from their nest, but the presence of polymorphic broods may increase the chances of recognition errors. Using 17 microsatellite markers, we investigated the mating system of the Fan-tailed Gerygone to understand the mechanisms underlying nestling polymorphism. We hypothesised that extra-pair copulations would lead to a higher proportion of polymorphic broods caused by higher genetic variability, thus creating a trade-off between genetic benefits and host defence reliability. Extra-pair paternity occurred in 6 of 36 broods, which resulted in 6 of 69 offspring sired by extra-pair males. Broods with and without mixed paternity were comparably often parasitized. Extra-pair paternity did not influence the proportions of bright, dark and polymorphic broods. Compared to bright siblings in polymorphic broods, dark nestlings tended to have lower heterozygosity, particularly in loci associated with skin coloration. The results also suggested that there is no obstacle for genetic exchange between individuals from forest and savannah, possibly due to dispersal of offspring. We conclude that the Fan-tailed Gerygone is a socially monogamous species with a low rate of extra-pair paternity compared to closely related species. Extra-pair paternity increased offspring genetic variability without measurable associated costs by brood parasitism. The results highlight the importance of studying host mating systems to assess the trade-offs between host defence and offspring fitness in co-evolutionary arms races. PMID:29518150

Action on the Surface: Entomopathogenic Fungi versus the Insect Cuticle.

PubMed

Ortiz-Urquiza, Almudena; Keyhani, Nemat O

2013-07-16

Infections mediated by broad host range entomopathogenic fungi represent seminal observations that led to one of the first germ theories of disease and are a classic example of a co-evolutionary arms race between a pathogen and target hosts. These fungi are able to parasitize susceptible hosts via direct penetration of the cuticle with the initial and potentially determining interaction occurring between the fungal spore and the insect epicuticle. Entomogenous fungi have evolved mechanisms for adhesion and recognition of host surface cues that help direct an adaptive response that includes the production of: (a) hydrolytic, assimilatory, and/or detoxifying enzymes including lipase/esterases, catalases, cytochrome P450s, proteases, and chitinases; (b) specialized infectious structures, e.g., appressoria or penetrant tubes; and (c) secondary and other metabolites that facilitate infection. Aside from immune responses, insects have evolved a number of mechanisms to keep pathogens at bay that include: (a) the production of (epi) cuticular antimicrobial lipids, proteins, and metabolites; (b) shedding of the cuticle during development; and (c) behavioral-environmental adaptations such as induced fever, burrowing, and grooming, as well as potentially enlisting the help of other microbes, all intended to stop the pathogen before it can breach the cuticle. Virulence and host-defense can be considered to be under constant reciprocal selective pressure, and the action on the surface likely contributes to phenomena such as strain variation, host range, and the increased virulence often noted once a (low) virulent strain is "passaged" through an insect host. Since the cuticle represents the first point of contact and barrier between the fungus and the insect, the "action on the surface" may represent the defining interactions that ultimately can lead either to successful mycosis by the pathogen or successful defense by the host. Knowledge concerning the molecular mechanisms underlying this interaction can shed light on the ecology and evolution of virulence and can be used for rational design strategies at increasing the effectiveness of entomopathogenic fungi for pest control in field applications.

Great spotted cuckoo fledglings often receive feedings from other magpie adults than their foster parents: which magpies accept to feed foreign cuckoo fledglings?

PubMed

Soler, Manuel; Pérez-Contreras, Tomás; Ibáñez-Álamo, Juan Diego; Roncalli, Gianluca; Macías-Sánchez, Elena; de Neve, Liesbeth

2014-01-01

Natural selection penalizes individuals that provide costly parental care to non-relatives. However, feedings to brood-parasitic fledglings by individuals other than their foster parents, although anecdotic, have been commonly observed, also in the great spotted cuckoo (Clamator glandarius)--magpie (Pica pica) system, but this behaviour has never been studied in depth. In a first experiment, we here show that great spotted cuckoo fledglings that were translocated to a distant territory managed to survive. This implies that obtaining food from foreign magpies is a frequent and efficient strategy used by great spotted cuckoo fledglings. A second experiment, in which we presented a stuffed-cuckoo fledgling in magpie territories, showed that adult magpies caring for magpie fledglings responded aggressively in most of the trials and never tried to feed the stuffed cuckoo, whereas magpies that were caring for cuckoo fledglings reacted rarely with aggressive behavior and were sometimes disposed to feed the stuffed cuckoo. In a third experiment we observed feedings to post-fledgling cuckoos by marked adult magpies belonging to four different possibilities with respect to breeding status (i.e. composition of the brood: only cuckoos, only magpies, mixed, or failed breeding attempt). All non-parental feeding events to cuckoos were provided by magpies that were caring only for cuckoo fledglings. These results strongly support the conclusion that cuckoo fledglings that abandon their foster parents get fed by other adult magpies that are currently caring for other cuckoo fledglings. These findings are crucial to understand the co-evolutionary arms race between brood parasites and their hosts because they show that the presence of the host's own nestlings for comparison is likely a key clue to favour the evolution of fledgling discrimination and provide new insights on several relevant points such as learning mechanisms and multiparasitism.

The evolution of egg colour and patterning in birds.

PubMed

Kilner, R M

2006-08-01

Avian eggs differ so much in their colour and patterning from species to species that any attempt to account for this diversity might initially seem doomed to failure. Here I present a critical review of the literature which, when combined with the results of some comparative analyses, suggests that just a few selective agents can explain much of the variation in egg appearance. Ancestrally, bird eggs were probably white and immaculate. Ancient diversification in nest location, and hence in the clutch's vulnerability to attack by predators, can explain basic differences between bird families in egg appearance. The ancestral white egg has been retained by species whose nests are safe from attack by predators, while those that have moved to a more vulnerable nest site are now more likely to lay brown eggs, covered in speckles, just as Wallace hypothesized more than a century ago. Even blue eggs might be cryptic in a subset of nests built in vegetation. It is possible that some species have subsequently turned these ancient adaptations to new functions, for example to signal female quality, to protect eggs from damaging solar radiation, or to add structural strength to shells when calcium is in short supply. The threat of predation, together with the use of varying nest sites, appears to have increased the diversity of egg colouring seen among species within families, and among clutches within species. Brood parasites and their hosts have probably secondarily influenced the diversity of egg appearance. Each drives the evolution of the other's egg colour and patterning, as hosts attempt to avoid exploitation by rejecting odd-looking eggs from their nests, and parasites attempt to outwit their hosts by laying eggs that will escape detection. This co-evolutionary arms race has increased variation in egg appearance both within and between species, in parasites and in hosts, sometimes resulting in the evolution of egg colour polymorphisms. It has also reduced variation in egg appearance within host clutches, although the benefit thus gained by hosts is not clear.

Testing co-evolutionary hypotheses over geological timescales: interactions between Mesozoic non-avian dinosaurs and cycads.

PubMed

Butler, Richard J; Barrett, Paul M; Kenrick, Paul; Penn, Malcolm G

2009-02-01

The significance of co-evolution over ecological timescales is well established, yet it remains unclear to what extent co-evolutionary processes contribute to driving large-scale evolutionary and ecological changes over geological timescales. Some of the most intriguing and pervasive long-term co-evolutionary hypotheses relate to proposed interactions between herbivorous non-avian dinosaurs and Mesozoic plants, including cycads. Dinosaurs have been proposed as key dispersers of cycad seeds during the Mesozoic, and temporal variation in cycad diversity and abundance has been linked to dinosaur faunal changes. Here we assess the evidence for proposed hypotheses of trophic and evolutionary interactions between these two groups using diversity analyses, a new database of Cretaceous dinosaur and plant co-occurrence data, and a geographical information system (GIS) as a visualisation tool. Phylogenetic evidence suggests that the origins of several key biological properties of cycads (e.g. toxins, bright-coloured seeds) likely predated the origin of dinosaurs. Direct evidence of dinosaur-cycad interactions is lacking, but evidence from extant ecosystems suggests that dinosaurs may plausibly have acted as seed dispersers for cycads, although it is likely that other vertebrate groups (e.g. birds, early mammals) also played a role. Although the Late Triassic radiations of dinosaurs and cycads appear to have been approximately contemporaneous, few significant changes in dinosaur faunas coincide with the late Early Cretaceous cycad decline. No significant spatiotemporal associations between particular dinosaur groups and cycads can be identified - GIS visualisation reveals disparities between the spatiotemporal distributions of some dinosaur groups (e.g. sauropodomorphs) and cycads that are inconsistent with co-evolutionary hypotheses. The available data provide no unequivocal support for any of the proposed co-evolutionary interactions between cycads and herbivorous dinosaurs - diffuse co-evolutionary scenarios that are proposed to operate over geological timescales are plausible, but such hypotheses need to be firmly grounded on direct evidence of interaction and may be difficult to support given the patchiness of the fossil record.

Outcomes of Brood Parasite–Host Interactions Mediated by Egg Matching: Common Cuckoos Cuculus canorus versus Fringilla Finches

PubMed Central

Vikan, Johan Reinert; Fossøy, Frode; Huhta, Esa; Moksnes, Arne; Røskaft, Eivin; Stokke, Bård Gunnar

2011-01-01

Background Antagonistic species often interact via matching of phenotypes, and interactions between brood parasitic common cuckoos (Cuculus canorus) and their hosts constitute classic examples. The outcome of a parasitic event is often determined by the match between host and cuckoo eggs, giving rise to potentially strong associations between fitness and egg phenotype. Yet, empirical efforts aiming to document and understand the resulting evolutionary outcomes are in short supply. Methods/Principal Findings We used avian color space models to analyze patterns of egg color variation within and between the cuckoo and two closely related hosts, the nomadic brambling (Fringilla montifringilla) and the site fidelic chaffinch (F. coelebs). We found that there is pronounced opportunity for disruptive selection on brambling egg coloration. The corresponding cuckoo host race has evolved egg colors that maximize fitness in both sympatric and allopatric brambling populations. By contrast, the chaffinch has a more bimodal egg color distribution consistent with the evolutionary direction predicted for the brambling. Whereas the brambling and its cuckoo host race show little geographical variation in their egg color distributions, the chaffinch's distribution becomes increasingly dissimilar to the brambling's distribution towards the core area of the brambling cuckoo host race. Conclusion High rates of brambling gene flow is likely to cool down coevolutionary hot spots by cancelling out the selection imposed by a patchily distributed cuckoo host race, thereby promoting a matching equilibrium. By contrast, the site fidelic chaffinch is more likely to respond to selection from adapting cuckoos, resulting in a markedly more bimodal egg color distribution. The geographic variation in the chaffinch's egg color distribution could reflect a historical gradient in parasitism pressure. Finally, marked cuckoo egg polymorphisms are unlikely to evolve in these systems unless the hosts evolve even more exquisite egg recognition capabilities than currently possessed. PMID:21559400

Overcoming obstacles to interspecies hybridization of ash

Treesearch

Jennifer L. Koch; David W. Carey; Mary E. Mason; M. Nurul Islam-Faridi

2010-01-01

Tree species that share a long co-evolutionary history with insects and pathogens are likely to have developed mechanisms of resistance that allow them to coexist. When insects and pathogens are introduced to different parts of the world, high levels of susceptibility can be observed, presumably in part due to the lack of co-evolutionary history between the insect (or...

USSR Report, International Affairs

DTIC Science & Technology

1987-04-22

base at Greenham Common, where British women are now spending their fifth winter besieging the cruise missile stockpiles. It is going on in the court...Counterstrategy to the Plans for Preparing for War and the Buildup in the Arms Race"), R. Prasad ( India ) ("The Socioeconoraic Consequences of the Arms...The International Peace Institute in Vienna), D. ( Dalits ) (the UN Institute for Studying Disarmament Problems), and others attending the forum was

Prenuclear-age leaders and the nuclear arms race.

PubMed

Frank, Jerome D

1982-10-01

Nuclear arms are a phenomenon with no historical precedent, yet people--and their national leaders--confront the prospect of nuclear war with psychological attitudes from an earlier, simpler time. This paper considers the meaning of our image of the "enemy," analyzes the appropriateness and effectiveness of a policy of deterrence, and considers approaches to doing away with war and to easing international antagonisms through the pursuit of mutually beneficial goals.

Rhetorical analysis of Ronald Reagan's November 18, 1981, address on strategic arms reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preston, C.T. Jr.

1986-01-01

Ronald Reagan's addresses, news conferences, and statements on disarmament during his first term form the focus of this dissertation. The rhetoric of the Nuclear Freeze Campaign formed the background for the study of Reagan's response. A November 18, 1981, address before the National Press Club was selected as the representative anecdote for the disarmament rhetoric. Using Kenneth Burke's dramatistic method, the dissertation concludes that Reagan's effective choices in transformation, entitlement, and identification produced a disarmament drama that enabled many American listeners to cope with the arms race. The understandings created by this drama appealed to an audience that had beenmore » aroused by the freeze movement about the danger of nuclear war. Reagan's rhetorical choices included transforming the conflict of the people versus the arms race into a conflict between the people and the Soviet threat, entitling a nuclear buildup START to make it appear that reduction goes further than freezing weapons, and identifying with America's desire not to repeat past mistakes of history by promoting a need for a strong Alliance. Reagan reinforced the drama of an arms buildup as a road to peace. These choices, the constraints of freeze member's access to the media, and inconsistencies among freeze appeals, contributed significantly to the current lack of support for a nuclear freeze.« less

Nuclear Disarmament.

ERIC Educational Resources Information Center

Johnson, Christopher

1982-01-01

Material about nuclear disarmament and the arms race should be included in secondary school curricula. Teachers can present this technical, controversial, and frightening material in a balanced and comprehensible way. Resources for instructional materials are listed. (PP)

Global Perspectives in the Mathematics Classroom.

ERIC Educational Resources Information Center

Hudson, Brian

1990-01-01

Discusses the use of world problems in mathematics curriculum. Provides a topic on (1) life expectancy and the percentage of the population with access to safe drinking water and (2) the global arms race. (YP)

The arms race between tomato and Fusarium oxysporum.

PubMed

Takken, Frank; Rep, Martijn

2010-03-01

The interaction between tomato and Fusarium oxysporum f. sp. lycopersici has become a model system for the study of the molecular basis of disease resistance and susceptibility. Gene-for-gene interactions in this system have provided the basis for the development of tomato cultivars resistant to Fusarium wilt disease. Over the last 6 years, new insights into the molecular basis of these gene-for-gene interactions have been obtained. Highlights are the identification of three avirulence genes in F. oxysporum f. sp. lycopersici and the development of a molecular switch model for I-2, a nucleotide-binding and leucine-rich repeat-type resistance protein which mediates the recognition of the Avr2 protein. We summarize these findings here and present possible scenarios for the ongoing molecular arms race between tomato and F. oxysporum f. sp. lycopersici in both nature and agriculture.

Co-evolutionary data mining for fuzzy rules: automatic fitness function creation phase space, and experiments

NASA Astrophysics Data System (ADS)

Smith, James F., III; Blank, Joseph A.

2003-03-01

An approach is being explored that involves embedding a fuzzy logic based resource manager in an electronic game environment. Game agents can function under their own autonomous logic or human control. This approach automates the data mining problem. The game automatically creates a cleansed database reflecting the domain expert's knowledge, it calls a data mining function, a genetic algorithm, for data mining of the data base as required and allows easy evaluation of the information extracted. The co-evolutionary fitness functions, chromosomes and stopping criteria for ending the game are discussed. Genetic algorithm and genetic program based data mining procedures are discussed that automatically discover new fuzzy rules and strategies. The strategy tree concept and its relationship to co-evolutionary data mining are examined as well as the associated phase space representation of fuzzy concepts. The overlap of fuzzy concepts in phase space reduces the effective strategies available to adversaries. Co-evolutionary data mining alters the geometric properties of the overlap region known as the admissible region of phase space significantly enhancing the performance of the resource manager. Procedures for validation of the information data mined are discussed and significant experimental results provided.

A new chromosomal race of the house mouse, Mus musculus domesticus, in the Vulcano Island-Aeolian Archipelago, Italy.

PubMed

Solano, Emanuela; Castiglia, Riccardo; Corti, Marco

2007-07-01

In this paper we describe a new Robertsonian (Rb) race of the house mouse from Vulcano (Aeolian archipelago) through the identification of the metacentric chromosomes. We analysed fifteen mice. All the specimens were found to have the same karyotype 2n=26. This karyotype is characterized by Rb(1.2), Rb(3.9), Rb(4.13), Rb(5.14), Rb(8.12), Rb(10.16) and Rb(15.17). The differences between the race of Vulcano and the races in a neighbour island (Lipari) consist in the presence of Rb(10.16) and Rb(15.17) in the former and Rb(6.16) and Rb(10.15) in the latter. We discuss the possible hypotheses regarding the origin between these two races including the possible occurrence of a whole arm reciprocal translocation (WART) on the Vulcano island.

Arms Control and Missile Defense: Explaining Success and Failure in U.S.-Russian Cooperation

DTIC Science & Technology

2013-09-01

Security Service) GLCM Ground-Launched Cruise Missile GLONASS Global’naya Navigatsionnaya Sputnikovaya Sistema , or Global Navigation Satellite System...threat to us will only grow. We will be pulled into another round of the arms race that is beyond our capabilities . . . because we are already at...Global’naya Navigatsionnaya Sputnikovaya Sistema , or Global Navigation Satellite System).”111 Based on his review of events in Georgia, Vladimir

Evaluation of arm-leg coordination in flat breaststroke.

PubMed

Chollet, D; Seifert, L; Leblanc, H; Boulesteix, L; Carter, M

2004-10-01

This study proposes a new method to evaluate arm-leg coordination in flat breaststroke. Five arm and leg stroke phases were defined with a velocity-video system. Five time gaps quantified the time between arm and leg actions during three paces of a race (200 m, 100 m and 50 m) in 16 top level swimmers. Based on these time gaps, effective glide, effective propulsion, effective leg insweep and effective recovery were used to identify the different stroke phases of the body. A faster pace corresponded to increased stroke rate, decreased stroke length, increased propulsive phases, shorter glide phases, and a shorter T1 time gap, which measured the effective body glide. The top level swimmers showed short time gaps (T2, T3, T4, measuring the timing of arm-leg recoveries), which reflected the continuity in arm and leg actions. The measurement of these time gaps thus provides a pertinent evaluation of swimmers' skill in adapting their arm-leg coordination to biomechanical constraints.

Kids and the Bomb: Apocalyptic Anxieties?

ERIC Educational Resources Information Center

Bower, Bruce

1985-01-01

Examines what it means when youngsters tell researchers they are concerned about the nuclear arms race. The nuclear concerns picked up in surveys may be deep or they may indicate a superficial awareness of a hot political topic. (JN)

Bombendämmerung

NASA Astrophysics Data System (ADS)

Mueller, John

2011-02-01

The US writer Richard Rhodes has chronicled the history of nuclear weapons in three very well-received books, dealing in sequence with the making of the atomic bomb, the making of the hydrogen bomb and the making of the nuclear arms race.

Next step in the ongoing arms race between myxoma virus and wild rabbits in Australia is a novel disease phenotype

PubMed Central

Kerr, Peter J.; Cattadori, Isabella M.; Liu, June; Sim, Derek G.; Dodds, Jeff W.; Brooks, Jason W.; Kennett, Mary J.; Holmes, Edward C.

2017-01-01

In host–pathogen arms races, increases in host resistance prompt counteradaptation by pathogens, but the nature of that counteradaptation is seldom directly observed outside of laboratory models. The best-documented field example is the coevolution of myxoma virus (MYXV) in European rabbits. To understand how MYXV in Australia has continued to evolve in wild rabbits under intense selection for genetic resistance to myxomatosis, we compared the phenotypes of the progenitor MYXV and viral isolates from the 1950s and the 1990s in laboratory rabbits with no resistance. Strikingly, and unlike their 1950s counterparts, most virus isolates from the 1990s induced a highly lethal immune collapse syndrome similar to septic shock. Thus, the next step in this canonical case of coevolution after a species jump has been further escalation by the virus in the face of widespread host resistance. PMID:28808019

JPRS Report, Soviet Union, International Affairs

DTIC Science & Technology

1988-02-09

and space arms in Geneva were just marking time and in essence had reached a dead end. The arms race was continuing. It had become obvious that the...will be reduced to one-fourth. Decentralization of the management of the country’s national economy is the essence of administrative restructuring...bringing home to everyone the essence of the questions put to the popular vote, with the result that many awoke to their responsibility for the fate of

Worldwide Report, Arms Control.

DTIC Science & Technology

1985-11-22

dinosaurs (and a large number of other species which disappeared "simultaneously") might have become extinct because a large comet hit the earth’s...clear yet aeain the reasons why Washington is in such haste in the arms race for "star wars" and why it refuses to assume a commitment not to be...Kolesnichenko says: [Begin Kolesnichenko recording in Russian with English translation] In an effort to calm the American public and provide a logical reason

Navigating the Repeal of Don’t Ask, Don’t Tell

DTIC Science & Technology

2011-03-24

different categories, except for non-heterosexuals. They serve in the U.S. Armed Forces now and they will continue to serve in the future. Legal ...categories, except for non-heterosexuals. They serve in the U.S. Armed Forces now and they will continue to serve in the future. Legal integration... homosexuals . This shortlist can be boiled down to sex, race, religion, ethnicity, age and sexual orientation. Over the years, the U.S. military

The Carrier Arms Race in East and South Asia: Responses to a Changing Strategic Environment

DTIC Science & Technology

2014-09-01

analysis of Japan’s strategic trajectory and the development of new classes of helicopter destroyers. Koda describes the U.S.-Japan security alliance... Koda , “A New Carrier Race? Strategy, Force Planning, and JS Hyuga.” Naval War College Review 64, no. 3 (2011): 32–51. 11 Korean Institute for...According to retired Vice Admiral Yoji Koda , “Hyuga realizes a long-standing dream and goal of the JMSDF, which has wanted to be a truly capable

Parasite transmission among relatives halts Red Queen dynamics.

PubMed

Greenspoon, Philip B; Mideo, Nicole

2017-03-01

The theory that coevolving hosts and parasites create a fluctuating selective environment for one another (i.e., produce Red Queen dynamics) has deep roots in evolutionary biology; yet empirical evidence for Red Queen dynamics remains scarce. Fluctuating coevolutionary dynamics underpin the Red Queen hypothesis for the evolution of sex, as well as hypotheses explaining the persistence of genetic variation under sexual selection, local parasite adaptation, the evolution of mutation rate, and the evolution of nonrandom mating. Coevolutionary models that exhibit Red Queen dynamics typically assume that hosts and parasites encounter one another randomly. However, if related individuals aggregate into family groups or are clustered spatially, related hosts will be more likely to encounter parasites transmitted by genetically similar individuals. Using a model that incorporates familial parasite transmission, we show that a slight degree of familial parasite transmission is sufficient to halt coevolutionary fluctuations. Our results predict that evidence for Red Queen dynamics, and its evolutionary consequences, are most likely to be found in biological systems in which hosts and parasites mix mainly at random, and are less likely to be found in systems with familial aggregation. This presents a challenge to the Red Queen hypothesis and other hypotheses that depend on coevolutionary cycling. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Brood-parasite interactions between great spotted cuckoos and magpies: a model system for studying coevolutionary relationships.

PubMed

Soler, Juan; Soler, Manuel

2000-11-01

Brood parasitism is one of the systems where coevolutionary processes have received the most research. Here, we review experiments that suggest a coevolutionary process between the great spotted cuckoo (Clamator glandarius) and its magpie (Pica pica) host. We focus on different stages of establishment of the relationship, from cuckoos selecting individual hosts and hosts defending their nests from adult cuckoos, to the ability of magpies to detect cuckoo eggs in their nests. Novel coevolutionary insights emerge from our synthesis of the literature, including how the evolution of "Mafia" behaviour in cuckoos does not necessarily inhibit the evolution of host recognition and rejection of cuckoo offspring, and how different populations of black-billed magpies in Europe have evolved specific host traits (e.g. nest and clutch size) as a result of interactions with the great spotted cuckoo. Finally, the results of the synthesis reveal the importance of using a meta-population approach when studying coevolution. This is especially relevant in those cases where gene flow among populations with different degrees of brood parasitism explains patterns of coexistence between defensive and non-defensive host phenotypes. We propose the use of a meta-population approach to distinguish between the "evolutionary equilibrium" hypothesis and the "evolutionary lag" hypothesis.

Mapping resistance to the Ug99 race group of the stem rust pathogen in a spring wheat landrace.

PubMed

Babiker, E M; Gordon, T C; Chao, S; Newcomb, M; Rouse, M N; Jin, Y; Wanyera, R; Acevedo, M; Brown-Guedira, G; Williamson, S; Bonman, J M

2015-04-01

A new gene for Ug99 resistance from wheat landrace PI 374670 was detected on the long arm of chromosome 7A. Wheat landrace PI 374670 has seedling and field resistance to stem rust caused by Puccinia graminis f. sp tritici Eriks. & E. Henn (Pgt) race TTKSK. To elucidate the inheritance of resistance, 216 BC1F2 families, 192 double haploid (DH) lines, and 185 recombinant inbred lines (RILs) were developed by crossing PI 374670 and the susceptible line LMPG-6. The parents and progeny were evaluated for seedling resistance to Pgt races TTKSK, MCCFC, and TPMKC. The DH lines were tested in field stem rust nurseries in Kenya and Ethiopia. The DH lines were genotyped with the 90K wheat iSelect SNP genotyping platform. Goodness-of-fit tests indicated that a single dominant gene in PI 374670 conditioned seedling resistance to the three Pgt races. The seedling resistance locus mapped to the long arm of chromosome 7A and this result was verified in the RIL population screened with the flanking SNP markers using KASP assays. In the same region, a major QTL for field resistance was detected in a 7.7 cM interval and explained 34-54 and 29-36% of the variation in Kenya and Ethiopia, respectively. Results from tests with specific Pgt races and the csIH81 marker showed that the resistance was not due to Sr22. Thus, a new stem rust resistance gene or allele, either closely linked or allelic to Sr15, is responsible for the seedling and field resistance of PI 374670 to Ug99.

Arms control and the 1990 NPT review conference: Workshop summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pilat, J.F.

1990-07-01

The Center for National Security Studies of the Los Alamos National Laboratory and the Department of Energy's Office of Arms Control held a workshop on Arms Control and the 1990 NPT Review Conference'' on December 5--6, 1989, at Los Alamos. The fundamental objective of the Treaty on the Nonproliferation of Nuclear Weapons (NPT) is to prevent the spread of nuclear weapons to states that do not possess them; however, another of the NPT objectives is to encourage arms control efforts in the nuclear and nonnuclear arenas. Accordingly, under Article VI, each of the Parties to the Treaty undertakes to pursuemore » negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control.'' This paper discusses ideas put forward at the Review Conference.« less

An Approach to Naval Arms Control

DTIC Science & Technology

1989-07-01

commentary pro and con on the control of SLCM’s has 9 I: been uttered by people not known to be expert on maritime strategy and the roles of navies in crisis ... transcultural misunderstanding is indeed deep and widespread (e.g., witness the surprise on the part of America’s leading television pundits that China’s...force on behalf of (U.S definition of) international order in situations short of war; 0 alliance cohesion; 37 i * crisis , arms race, and political

The spectre of race in American medicine.

PubMed

Fofana, Mariam O

2013-12-01

Controversies and debates surrounding race have long been a fixture in American medicine. In the past, the biological concept of race-the idea that race is biologically determined and meaningful-has served to justify the institution of slavery and the conduct of unethical research trials. Although these days may seem far behind, contemporary debates over the race-specific approval of drugs and the significance of genetic differences are evidence that race still yields tremendous influence on medical research and clinical practice. In many ways, the use of race in medicine today reflects the internalisation of racial hierarchies borne out of the history of slavery and state-mandated segregation, and there is still much uncertainty over its benefits and harms. Although using race in research can help elucidate disparities, the reflexive use of race as a variable runs the risk of reifying the biological concept of race and blinding researchers to important underlying factors such as socioeconomic status. Similarly, in clinical practice, the use of race in assessing a patient's risk of certain conditions (eg, sickle cell) turns harmful when the heuristic becomes a rule. Through selected historical and contemporary examples, I aim to show how the biological concept of race that gave rise to past abuses remains alive and harmful, and propose changes in medical education as a potential solution. By learning from the past, today's physicians will be better armed to discern-and correct-the ways in which contemporary medicine perpetuates historical injustices.

Predicting protein folding rate change upon point mutation using residue-level coevolutionary information.

PubMed

Mallik, Saurav; Das, Smita; Kundu, Sudip

2016-01-01

Change in folding kinetics of globular proteins upon point mutation is crucial to a wide spectrum of biological research, such as protein misfolding, toxicity, and aggregations. Here we seek to address whether residue-level coevolutionary information of globular proteins can be informative to folding rate changes upon point mutations. Generating residue-level coevolutionary networks of globular proteins, we analyze three parameters: relative coevolution order (rCEO), network density (ND), and characteristic path length (CPL). A point mutation is considered to be equivalent to a node deletion of this network and respective percentage changes in rCEO, ND, CPL are found linearly correlated (0.84, 0.73, and -0.61, respectively) with experimental folding rate changes. The three parameters predict the folding rate change upon a point mutation with 0.031, 0.045, and 0.059 standard errors, respectively. © 2015 Wiley Periodicals, Inc.

Molecular determinants of resistance to Verticillium dahliae in potato

USDA-ARS?s Scientific Manuscript database

A constant evolutionary arms race between host resistance genes and pathogen effectors determine adaptive fitness. Therefore, identification of both host resistance genes and pathogen effectors is important in devising effective strategies to control disease. In tomato, resistance to Verticillium da...

The Spectre of Race in American Medicine

PubMed Central

Fofana, Mariam O.

2014-01-01

Controversies and debates surrounding race have long been a fixture in American medicine. In the past, the biological concept of race—the idea that race is biologically determined and meaningful—has served to justify the institution of slavery and the conduct of unethical research trials. Although these days may seem far behind, contemporary debates over the race-specific approval of drugs and the significance of genetic differences are evidence that race still yields tremendous influence on medical research and clinical practice. In many ways, the use of race in medicine today reflects the internalization of racial hierarchies borne out of the history of slavery and state-mandated segregation, and there is still much uncertainty over its benefits and harms. Although using race in research can help elucidate disparities, the reflexive use of race as a variable runs the risk of reifying the biological concept of race and blinding researchers to important underlying factors such as socioeconomic status. Similarly, in clinical practice, the use of race in assessing a patient’s risk of certain conditions (e.g., sickle cell) turns harmful when the heuristic becomes a rule. Through selected historical and contemporary examples, I aim to show how the biological concept of race that gave rise to past abuses remains alive and harmful and propose changes in medical education as a potential solution. By learning from the past, today’s physicians will be better armed to discern—and correct—the ways in which contemporary medicine perpetuates historical injustices. PMID:23988563

The evolution of early cellular systems viewed through the lens of biological interactions.

PubMed

Poole, Anthony M; Lundin, Daniel; Rytkönen, Kalle T

2015-01-01

The minimal cell concept represents a pragmatic approach to the question of how few genes are required to run a cell. This is a helpful way to build a parts-list, and has been more successful than attempts to deduce a minimal gene set for life by inferring the gene repertoire of the last universal common ancestor, as few genes trace back to this hypothetical ancestral state. However, the study of minimal cellular systems is the study of biological outliers where, by practical necessity, coevolutionary interactions are minimized or ignored. In this paper, we consider the biological context from which minimal genomes have been removed. For instance, some of the most reduced genomes are from endosymbionts and are the result of coevolutionary interactions with a host; few such organisms are "free-living." As few, if any, biological systems exist in complete isolation, we expect that, as with modern life, early biological systems were part of an ecosystem, replete with organismal interactions. We favor refocusing discussions of the evolution of cellular systems on processes rather than gene counts. We therefore draw a distinction between a pragmatic minimal cell (an interesting engineering problem), a distributed genome (a system resulting from an evolutionary transition involving more than one cell) and the looser coevolutionary interactions that are ubiquitous in ecosystems. Finally, we consider the distributed genome and coevolutionary interactions between genomic entities in the context of early evolution.

Coevolutionary Free Lunches

NASA Technical Reports Server (NTRS)

Wolpert, David H.; Macready, William G.

2005-01-01

Recent work on the mathematical foundations of optimization has begun to uncover its rich structure. In particular, the "No Free Lunch" (NFL) theorems state that any two algorithms are equivalent when their performance is averaged across all possible problems. This highlights the need for exploiting problem-specific knowledge to achieve better than random performance. In this paper we present a general framework covering more search scenarios. In addition to the optimization scenarios addressed in the NFL results, this framework covers multi-armed bandit problems and evolution of multiple co-evolving players. As a particular instance of the latter, it covers "self-play" problems. In these problems the set of players work together to produce a champion, who then engages one or more antagonists in a subsequent multi-player game. In contrast to the traditional optimization case where the NFL results hold, we show that in self-play there are free lunches: in coevolution some algorithms have better performance than other algorithms, averaged across all possible problems. We consider the implications of these results to biology where there is no champion.

Sex hormone binding globulin and sex steroids among premenopausal women in the diabetes prevention program.

PubMed

Kim, Catherine; Pi-Sunyer, Xavier; Barrett-Connor, Elizabeth; Stentz, Frankie B; Murphy, Mary Beth; Kong, Shengchun; Nan, Bin; Kitabchi, Abbas E

2013-07-01

It is unknown whether intensive lifestyle modification (ILS) or metformin changes sex steroids among premenopausal women without a history of polycystic ovarian syndrome (PCOS). We examined 1-year intervention impact on sex steroids (estradiol, testosterone, dehydroepiandrosterone, and androstenedione [A4]) and SHBG and differences by race/ethnicity. A subgroup of Diabetes Prevention Program participants who were premenopausal, not using estrogen, without a history of PCOS or irregular menses, and who reported non-Hispanic white (NHW), Hispanic, or African-American race/ethnicity (n = 301). Randomization arms were 1) ILS with the goals of weight reduction of 7% of initial weight and 150 minutes per week of moderate intensity exercise, 2) metformin 850 mg twice a day, or 3) placebo. Neither intervention changed sex steroids compared to placebo. ILS, but not metformin, increased median SHBG by 3.1 nmol/L (~11%) compared to decreases of 1.1 nmol/L in the placebo arm (P < .05). This comparison remained significant after adjustment for changes in covariates including waist circumference. However, associations with glucose were not significant. Median baseline A4 was lower in Hispanics compared to NHWs (5.7 nmol/L vs 6.5 nmol/L, P < .05) and increases in A4 were greater in Hispanics compared to NHWs (3.0 nmol/ vs 1.2 nmol/L, P < .05), and these differences did not differ significantly by intervention arm. No other racial/ethnic differences were significant. Among premenopausal glucose-intolerant women, no intervention changed sex steroids. ILS increased SHBG, although associations with glucose were not significant. SHBG and sex steroids were similar by race/ethnicity, with the possible exception of lower baseline A4 levels in Hispanics compared to NHWs.

Molecular and cytogenetic characterization of a durum wheat-Aegilops speltoides chromosome translocation conferring resistance to stem rust.

PubMed

Faris, Justin D; Xu, Steven S; Cai, Xiwen; Friesen, Timothy L; Jin, Yue

2008-01-01

Stem rust is a serious disease of wheat that has caused historical epidemics, but it has not been a threat in recent decades in North America owing to the eradication of the alternative host and deployment of resistant cultivars. However, the recent emergence of Ug99 (or race TTKS) poses a threat to global wheat production because most currently grown wheat varieties are susceptible. In this study, we evaluated a durum wheat-Aegilops speltoides chromosome translocation line (DAS15) for reaction to Ug99 and six other races of stem rust, and used molecular and cytogenetic tools to characterize the translocation. DAS15 was resistant to all seven races of stem rust. Two durum-Ae. speltoides translocated chromosomes were detected in DAS15. One translocation involved the short arm, centromere, and a major portion of the long arm of Ae. speltoides chromosome 2S and a small terminal segment from durum chromosome arm 2BL. Thus, this translocated chromosome is designated T2BL-2SL*2SS. Cytogenetic mapping assigned the resistance gene(s) in DAS15 to the Ae. speltoides segment in T2BL-2SL*2SS. The Ae. speltoides segment in the other translocated chromosome did not harbour stem rust resistance. A comparison of DAS15 and the wheat stocks carrying the Ae. speltoides-derived resistance genes Sr32 and Sr39 indicated that stem rust resistance gene present in DAS15 is likely novel and will be useful for developing germplasm with resistance to Ug99. Efforts to reduce Ae. speltoides chromatin in T2BL-2SL*2SS are currently in progress.

Genome-Wide Linkage and Association Mapping of Halo Blight Resistance in Common Bean to Race 6 of the Globally Important Bacterial Pathogen

PubMed Central

Tock, Andrew J.; Fourie, Deidré; Walley, Peter G.; Holub, Eric B.; Soler, Alvaro; Cichy, Karen A.; Pastor-Corrales, Marcial A.; Song, Qijian; Porch, Timothy G.; Hart, John P.; Vasconcellos, Renato C. C.; Vicente, Joana G.; Barker, Guy C.; Miklas, Phillip N.

2017-01-01

Pseudomonas syringae pv. phaseolicola (Psph) Race 6 is a globally prevalent and broadly virulent bacterial pathogen with devastating impact causing halo blight of common bean (Phaseolus vulgaris L.). Common bean lines PI 150414 and CAL 143 are known sources of resistance against this pathogen. We constructed high-resolution linkage maps for three recombinant inbred populations to map resistance to Psph Race 6 derived from the two common bean lines. This was complemented with a genome-wide association study (GWAS) of Race 6 resistance in an Andean Diversity Panel of common bean. Race 6 resistance from PI 150414 maps to a single major-effect quantitative trait locus (QTL; HB4.2) on chromosome Pv04 and confers broad-spectrum resistance to eight other races of the pathogen. Resistance segregating in a Rojo × CAL 143 population maps to five chromosome arms and includes HB4.2. GWAS detected one QTL (HB5.1) on chromosome Pv05 for resistance to Race 6 with significant influence on seed yield. The same HB5.1 QTL, found in both Canadian Wonder × PI 150414 and Rojo × CAL 143 populations, was effective against Race 6 but lacks broad resistance. This study provides evidence for marker-assisted breeding for more durable halo blight control in common bean by combining alleles of race-nonspecific resistance (HB4.2 from PI 150414) and race-specific resistance (HB5.1 from cv. Rojo). PMID:28736566

Physics and Modern Warfare: The Awkward Silence.

ERIC Educational Resources Information Center

Woollett, E. L.

1980-01-01

Discusses the great dependence of the present arms race on a healthy physics enterprise and the pervasive connections between pure and applied science and military needs. This discussion is intended to orient college students about some problems directly related to progress made in science. (HM)

Is healthy competition healthy? New evidence of the impact of hospital competition.

PubMed

Gift, Thomas L; Arnould, Richard; DeBrock, Larry

2002-01-01

Competition among hospitals is commonly regarded as inefficient due to the medical arms race phenomenon, but most evidence for this hypothesis predates the Medicare prospective payment system and preferred provider legislation. Recent studies indicate hospital competition reduces costs and prices, but nearly all such research has focused on California. We add to the body of literature that analyzes the effects of competition in hospital markets. Using data from the state of Washington, we show that hospitals assume more risk in competitive markets by being more likely to accept prospective payment arrangements with insurers. If the arrangement is retrospective, the hospital is more likely to offer a discount as the number of competing hospitals increases. Both findings indicate that competitive forces operate the same in hospital markets as in most others: as the number of competitors increases, prices decrease and market power shifts from the suppliers to purchasers. The medical arms race hypothesis that favors more concentrated hospital markets no longer appears to be valid.

The relationship between consistency of propulsive cycles and maximum angular velocity during wheelchair racing.

PubMed

Wang, Yong Tai; Vrongistinos, Konstantinos Dino; Xu, Dali

2008-08-01

The purposes of this study were to examine the consistency of wheelchair athletes' upper-limb kinematics in consecutive propulsive cycles and to investigate the relationship between the maximum angular velocities of the upper arm and forearm and the consistency of the upper-limb kinematical pattern. Eleven elite international wheelchair racers propelled their own chairs on a roller while performing maximum speeds during wheelchair propulsion. A Qualisys motion analysis system was used to film the wheelchair propulsive cycles. Six reflective markers placed on the right shoulder, elbow, wrist joints, metacarpal, wheel axis, and wheel were automatically digitized. The deviations in cycle time, upper-arm and forearm angles, and angular velocities among these propulsive cycles were analyzed. The results demonstrated that in the consecutive cycles of wheelchair propulsion the increased maximum angular velocity may lead to increased variability in the upper-limb angular kinematics. It is speculated that this increased variability may be important for the distribution of load on different upper-extremity muscles to avoid the fatigue during wheelchair racing.

Type III CRISPR-Cas systems can provide redundancy to counteract viral escape from type I systems.

PubMed

Silas, Sukrit; Lucas-Elio, Patricia; Jackson, Simon A; Aroca-Crevillén, Alejandra; Hansen, Loren L; Fineran, Peter C; Fire, Andrew Z; Sánchez-Amat, Antonio

2017-08-17

CRISPR-Cas-mediated defense utilizes information stored as spacers in CRISPR arrays to defend against genetic invaders. We define the mode of target interference and role in antiviral defense for two CRISPR-Cas systems in Marinomonas mediterranea . One system (type I-F) targets DNA. A second system (type III-B) is broadly capable of acquiring spacers in either orientation from RNA and DNA, and exhibits transcription-dependent DNA interference. Examining resistance to phages isolated from Mediterranean seagrass meadows, we found that the type III-B machinery co-opts type I-F CRISPR-RNAs. Sequencing and infectivity assessments of related bacterial and phage strains suggests an 'arms race' in which phage escape from the type I-F system can be overcome through use of type I-F spacers by a horizontally-acquired type III-B system. We propose that the phage-host arms race can drive selection for horizontal uptake and maintenance of promiscuous type III interference modules that supplement existing host type I CRISPR-Cas systems.

An obligate brood parasite trapped in the intraspecific arms race of its hosts.

PubMed

Lyon, Bruce E; Eadie, John McA

2004-11-18

Reciprocal selection pressures often lead to close and adaptive matching of traits in coevolved species. A failure of one species to match the evolutionary trajectories of another is often attributed to evolutionary lags or to differing selection pressures across a geographic mosaic. Here we show that mismatches in adaptation of interacting species--an obligate brood parasitic duck and each of its two main hosts--are best explained by the evolutionary dynamics within the host species. Rejection of the brood parasite's eggs was common by both hosts, despite a lack of detectable cost of parasitism to the hosts. Egg rejection markedly reduced parasite fitness, but egg mimicry experiments revealed no phenotypic natural selection for more mimetic parasitic eggs. These paradoxical results were resolved by the discovery of intraspecific brood parasitism and conspecific egg rejection within the hosts themselves. The apparent arms race between species seems instead to be an incidental by-product of within-species conflict, with little recourse for evolutionary response by the parasite.

Age, gender, and race/ethnic differences in total body and subregional bone density.

PubMed

Looker, A C; Melton, L J; Harris, T; Borrud, L; Shepherd, J; McGowan, J

2009-07-01

Total body bone density of adults from National Health and Nutrition Examination Survey (NHANES) 1999-2004 differed as expected for some groups (men>women and blacks>whites) but not others (whites>Mexican Americans). Cross-sectional age patterns in bone mineral density (BMD) of older adults differed at skeletal sites that varied by degree of weight-bearing. Total body dual-energy X-ray absorptiometry (DXA) data offer the opportunity to compare bone density of demographic groups across the entire skeleton. The present study uses total body DXA data (Hologic QDR 4500A, Hologic, Bedford MA, USA) from the NHANES 1999-2004 to examine BMD of the total body and selected skeletal subregions in a wide age range of adult men and women from three race/ethnic groups. Total body, lumbar spine, pelvis, right leg, and left arm BMD and lean mass from 13,091 adults aged 20 years and older were used. The subregions were chosen to represent sites with different degrees of weight-bearing. Mean BMD varied in expected ways for some demographic characteristics (men>women and non-Hispanic blacks>non-Hispanic whites) but not others (non-Hispanic whites>Mexican Americans). Differences in age patterns in BMD also emerged for some characteristics (sex) but not others (race/ethnicity). Differences in cross-sectional age patterns in BMD and lean mass by degree of weight-bearing in older adults were observed for the pelvis, leg, and arm. This information may be useful for generating hypotheses about age, race, and sex differences in fracture risk in the population.

Beauty is in the efficient coding of the beholder.

PubMed

Renoult, Julien P; Bovet, Jeanne; Raymond, Michel

2016-03-01

Sexual ornaments are often assumed to be indicators of mate quality. Yet it remains poorly known how certain ornaments are chosen before any coevolutionary race makes them indicative. Perceptual biases have been proposed to play this role, but known biases are mostly restricted to a specific taxon, which precludes evaluating their general importance in sexual selection. Here we identify a potentially universal perceptual bias in mate choice. We used an algorithm that models the sparseness of the activity of simple cells in the primary visual cortex (or V1) of humans when coding images of female faces. Sparseness was found positively correlated with attractiveness as rated by men and explained up to 17% of variance in attractiveness. Because V1 is adapted to process signals from natural scenes, in general, not faces specifically, our results indicate that attractiveness for female faces is influenced by a visual bias. Sparseness and more generally efficient neural coding are ubiquitous, occurring in various animals and sensory modalities, suggesting that the influence of efficient coding on mate choice can be widespread in animals.

Assortative sociality, limited dispersal, infectious disease and the genesis of the global pattern of religion diversity

PubMed Central

Fincher, Corey L; Thornhill, Randy

2008-01-01

Why are religions far more numerous in the tropics compared with the temperate areas? We propose, as an answer, that more religions have emerged and are maintained in the tropics because, through localized coevolutionary races with hosts, infectious diseases select for three anticontagion behaviours: in-group assortative sociality; out-group avoidance; and limited dispersal. These behaviours, in turn, create intergroup boundaries that effectively fractionate, isolate and diversify an original culture leading to the genesis of two or more groups from one. Religion is one aspect of a group's culture that undergoes this process. If this argument is correct then, across the globe, religion diversity should correlate positively with infectious disease diversity, reflecting an evolutionary history of antagonistic coevolution between parasites and hosts and subsequent religion genesis. We present evidence that supports this model: for a global sample of traditional societies, societal range size is reduced in areas with more pathogens compared with areas with few pathogens, and in contemporary countries religion diversity is positively related to two measures of parasite stress. PMID:18664438

Hybrid Co-Evolutionary Motion Planning via Visibility-Based Repair

NASA Technical Reports Server (NTRS)

Dozier, Gerry; McCullough, Shaun; Brown, Edward, Jr.; Homaifar, Abdollah; Bikdash, Mar-wan

1997-01-01

This paper introduces a hybrid co-evolutionary system for global motion planning within unstructured environments. This system combines the concept of co-evolutionary search along with a concept that we refer to as the visibility-based repair to form a hybrid which quickly transforms infeasible motions into feasible ones. Also, this system makes use of a novel representation scheme for the obstacles within an environment. Our hybrid evolutionary system differs from other evolutionary motion planners in that (1) more emphasis is placed on repairing infeasible motions to develop feasible motions rather than using simulated evolution exclusively as a means of discovering feasible motions, (2) a continuous map of the environment is used rather than a discretized map, and (3) it develops global motion plans for multiple mobile destinations by co-evolving populations of sub-global motion plans. In this paper, we demonstrate the effectiveness of this system by using it to solve two challenging motion planning problems where multiple targets try to move away from a point robot.

The venom-gland transcriptome of the eastern coral snake (Micrurus fulvius) reveals high venom complexity in the intragenomic evolution of venoms

PubMed Central

2013-01-01

Background Snake venom is shaped by the ecology and evolution of venomous species, and signals of positive selection in toxins have been consistently documented, reflecting the role of venoms as an ecologically critical phenotype. New World coral snakes (Elapidae) are represented by three genera and over 120 species and subspecies that are capable of causing significant human morbidity and mortality, yet coral-snake venom composition is poorly understood in comparison to that of Old World elapids. High-throughput sequencing is capable of identifying thousands of loci, while providing characterizations of expression patterns and the molecular evolutionary forces acting within the venom gland. Results We describe the de novo assembly and analysis of the venom-gland transcriptome of the eastern coral snake (Micrurus fulvius). We identified 1,950 nontoxin transcripts and 116 toxin transcripts. These transcripts accounted for 57.1% of the total reads, with toxins accounting for 45.8% of the total reads. Phospholipases A2 and three-finger toxins dominated expression, accounting for 86.0% of the toxin reads. A total of 15 toxin families were identified, revealing venom complexity previously unknown from New World coral snakes. Toxins exhibited high levels of heterozygosity relative to nontoxins, and overdominance may favor gene duplication leading to the fixation of advantageous alleles. Phospholipase A2 expression was uniformly distributed throughout the class while three-finger toxin expression was dominated by a handful of transcripts, and phylogenetic analyses indicate that toxin divergence may have occurred following speciation. Positive selection was detected in three of the four most diverse toxin classes, suggesting that venom diversification is driven by recurrent directional selection. Conclusions We describe the most complete characterization of an elapid venom gland to date. Toxin gene duplication may be driven by heterozygote advantage, as the frequency of polymorphic toxin loci was significantly higher than that of nontoxins. Diversification among toxins appeared to follow speciation reflecting species-specific adaptation, and this divergence may be directly related to dietary shifts and is suggestive of a coevolutionary arms race. PMID:23915248

The venom-gland transcriptome of the eastern coral snake (Micrurus fulvius) reveals high venom complexity in the intragenomic evolution of venoms.

PubMed

Margres, Mark J; Aronow, Karalyn; Loyacano, Jacob; Rokyta, Darin R

2013-08-02

Snake venom is shaped by the ecology and evolution of venomous species, and signals of positive selection in toxins have been consistently documented, reflecting the role of venoms as an ecologically critical phenotype. New World coral snakes (Elapidae) are represented by three genera and over 120 species and subspecies that are capable of causing significant human morbidity and mortality, yet coral-snake venom composition is poorly understood in comparison to that of Old World elapids. High-throughput sequencing is capable of identifying thousands of loci, while providing characterizations of expression patterns and the molecular evolutionary forces acting within the venom gland. We describe the de novo assembly and analysis of the venom-gland transcriptome of the eastern coral snake (Micrurus fulvius). We identified 1,950 nontoxin transcripts and 116 toxin transcripts. These transcripts accounted for 57.1% of the total reads, with toxins accounting for 45.8% of the total reads. Phospholipases A(2) and three-finger toxins dominated expression, accounting for 86.0% of the toxin reads. A total of 15 toxin families were identified, revealing venom complexity previously unknown from New World coral snakes. Toxins exhibited high levels of heterozygosity relative to nontoxins, and overdominance may favor gene duplication leading to the fixation of advantageous alleles. Phospholipase A(2) expression was uniformly distributed throughout the class while three-finger toxin expression was dominated by a handful of transcripts, and phylogenetic analyses indicate that toxin divergence may have occurred following speciation. Positive selection was detected in three of the four most diverse toxin classes, suggesting that venom diversification is driven by recurrent directional selection. We describe the most complete characterization of an elapid venom gland to date. Toxin gene duplication may be driven by heterozygote advantage, as the frequency of polymorphic toxin loci was significantly higher than that of nontoxins. Diversification among toxins appeared to follow speciation reflecting species-specific adaptation, and this divergence may be directly related to dietary shifts and is suggestive of a coevolutionary arms race.

Action on the Surface: Entomopathogenic Fungi versus the Insect Cuticle

PubMed Central

Ortiz-Urquiza, Almudena; Keyhani, Nemat O.

2013-01-01

Infections mediated by broad host range entomopathogenic fungi represent seminal observations that led to one of the first germ theories of disease and are a classic example of a co-evolutionary arms race between a pathogen and target hosts. These fungi are able to parasitize susceptible hosts via direct penetration of the cuticle with the initial and potentially determining interaction occurring between the fungal spore and the insect epicuticle. Entomogenous fungi have evolved mechanisms for adhesion and recognition of host surface cues that help direct an adaptive response that includes the production of: (a) hydrolytic, assimilatory, and/or detoxifying enzymes including lipase/esterases, catalases, cytochrome P450s, proteases, and chitinases; (b) specialized infectious structures, e.g., appressoria or penetrant tubes; and (c) secondary and other metabolites that facilitate infection. Aside from immune responses, insects have evolved a number of mechanisms to keep pathogens at bay that include: (a) the production of (epi) cuticular antimicrobial lipids, proteins, and metabolites; (b) shedding of the cuticle during development; and (c) behavioral-environmental adaptations such as induced fever, burrowing, and grooming, as well as potentially enlisting the help of other microbes, all intended to stop the pathogen before it can breach the cuticle. Virulence and host-defense can be considered to be under constant reciprocal selective pressure, and the action on the surface likely contributes to phenomena such as strain variation, host range, and the increased virulence often noted once a (low) virulent strain is “passaged” through an insect host. Since the cuticle represents the first point of contact and barrier between the fungus and the insect, the “action on the surface” may represent the defining interactions that ultimately can lead either to successful mycosis by the pathogen or successful defense by the host. Knowledge concerning the molecular mechanisms underlying this interaction can shed light on the ecology and evolution of virulence and can be used for rational design strategies at increasing the effectiveness of entomopathogenic fungi for pest control in field applications. PMID:26462424

Differing House Finch Cytokine Expression Responses to Original and Evolved Isolates of Mycoplasma gallisepticum.

PubMed

Vinkler, Michal; Leon, Ariel E; Kirkpatrick, Laila; Dalloul, Rami A; Hawley, Dana M

2018-01-01

The recent emergence of the poultry bacterial pathogen Mycoplasma gallisepticum (MG) in free-living house finches ( Haemorhous mexicanus ), which causes mycoplasmal conjunctivitis in this passerine bird species, resulted in a rapid coevolutionary arms-race between MG and its novel avian host. Despite extensive research on the ecological and evolutionary dynamics of this host-pathogen system over the past two decades, the immunological responses of house finches to MG infection remain poorly understood. We developed seven new probe-based one-step quantitative reverse transcription polymerase chain reaction assays to investigate mRNA expression of house finch cytokine genes ( IL1B, IL6, IL10, IL18, TGFB2, TNFSF15 , and CXCLi2 , syn. IL8L ). These assays were then used to describe cytokine transcription profiles in a panel of 15 house finch tissues collected at three distinct time points during MG infection. Based on initial screening that indicated strong pro-inflammatory cytokine expression during MG infection at the periorbital sites in particular, we selected two key house finch tissues for further characterization: the nictitating membrane, i.e., the internal eyelid in direct contact with MG, and the Harderian gland, the secondary lymphoid tissue responsible for regulation of periorbital immunity. We characterized cytokine responses in these two tissues for 60 house finches experimentally inoculated either with media alone (sham) or one of two MG isolates: the earliest known pathogen isolate from house finches (VA1994) or an evolutionarily more derived isolate collected in 2006 (NC2006), which is known to be more virulent. We show that the more derived and virulent isolate NC2006, relative to VA1994, triggers stronger local inflammatory cytokine signaling, with peak cytokine expression generally occurring 3-6 days following MG inoculation. We also found that the extent of pro-inflammatory interleukin 1 beta signaling was correlated with conjunctival MG loads and the extent of clinical signs of conjunctivitis, the main pathological effect of MG in house finches. These results suggest that the pathogenicity caused by MG infection in house finches is largely mediated by host pro-inflammatory immune responses, with important implications for the dynamics of host-pathogen coevolution.

Senseless Extravagance, Shocking Gaps

ERIC Educational Resources Information Center

Weissbourd, Richard; Dodge, Trevor

2012-01-01

Although most people in the United States believe, at least theoretically, in educational equality, fewer and fewer appear to care about the resource gaps between affluent and poor schools, says Weissbourd. He illustrates these gaps with vivid descriptions of what he calls an "opulence arms race" among affluent independent schools, but…

A Nuclear Freeze and a Noninterventionary Conventional Policy.

ERIC Educational Resources Information Center

Forsberg, Randall

1982-01-01

The history of the arms race between the United States and the Soviet Union is related, and the role assigned to conventional and nuclear forces in both countries is explained. A plea is made for a nuclear freeze and for reducing conventional forces as well. (PP)

76 FR 12934 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-09

... population. Some of the demographic information we collect is age, marital status, gender, Armed Forces status, education, race, origin, and family income. We use these data in conjunction with other data... data to correctly control estimates of other characteristics to the proper proportions of age, gender...

Speciation via autoimmunity: a dangerous mix.

PubMed

Phadnis, Nitin; Malik, Harmit S

2014-12-04

In this issue of Cell, Chae et al. find that genomic "hot spots" encoding NLR plant immune receptor genes are recurrently responsible for hybrid necrosis, highlighting the role of host-pathogen evolutionary arms races in driving the evolution of hybrid incompatibilities. Copyright © 2014 Elsevier Inc. All rights reserved.

Design optimization of rear uprights for UniMAP Automotive Racing Team Formula SAE racing car

NASA Astrophysics Data System (ADS)

Azmeer, M.; Basha, M. H.; Hamid, M. F.; Rahman, M. T. A.; Hashim, M. S. M.

2017-10-01

In an automobile, the rear upright are used to provide a physical mounting and links the suspension arms to the hub and wheel assembly. In this work, static structural and shape optimization analysis for rear upright for UniMAP’s Formula SAE racing car had been done using ANSYS software with the objective to reduce weight while maintaining the structural strength of the vehicle upright. During the shape optimization process, the component undergoes 25%, 50% and 75 % weight reduction in order to find the best optimal shape of the upright. The final design of the upright is developed considering the weight reduction, structural integrity and the manufacturability. The final design achieved 21 % weight reduction and is able to withstand several loads.

Predictor variables of performance in recreational male long-distance inline skaters.

PubMed

Knechtle, Beat; Knechtle, Patrizia; Rüst, Christoph Alexander; Senn, Oliver; Rosemann, Thomas; Lepers, Romuald

2011-06-01

We investigated the associations between selected anthropometric and training characteristics with race time in 84 recreational male long-distance inline skaters at the longest inline marathon in Europe, the 'Inline One-eleven' over 111 km in Switzerland, using bi- and multivariate analysis. The mean (s) race time was 264 (41) min. The bivariate analysis showed that age (r = 0.30), body mass (r = 0.42), body mass index (r = 0.35), circumference of upper arm (r = 0.32), circumference of thigh (r = 0.29), circumference of calf (r = 0.38), skin-fold of thigh (r = 0.22), skin-fold of calf (r = 0.27), the sum of skin-folds (r = 0.43), percent body fat (r = 0.45), duration per training unit in inline skating (r = 0.33), and speed during training (r = -0.46) were significantly and positively correlated to race time. Stepwise multiple regression showed that duration per training unit (P = 0.003), age (P = 0.029) and percent body fat (P = 0.016) were the best correlated with race time. Race time in a long-distance inline race such as the 'Inline One-eleven' over 111 km with a mean race time of ∼260 min might be predicted by the following equation (r(2) = 0.41): Race time (min) = 114.91 + 0:51* (duration per training unit, min) + 0:85* (age, years) +3:78* (body fat, %) for recreational long-distance inline skaters.

Intracyclic velocity variation and arm coordination assessment in swimmers with Down syndrome.

PubMed

Marques-Aleixo, Inês; Querido, Ana; Figueiredo, Pedro; Vilas-Boas, João Paulo; Corredeira, Rui; Daly, Daniel; Fernandes, Ricardo J

2013-01-01

This study examined the differences in intracycle velocity variation and arm coordination in front crawl in swimmers with Down syndrome in three breathing conditions. International swimmers with Down syndrome (N = 16) performed 3 × 20 m front crawl at 50 m race speed: without breathing, breathing to the preferred side, and breathing to the nonpreferred side. A two dimensional video movement analysis was performed using the APASystem. Breathing conditions were compared using Repeated Measures ANOVA. Swimming velocity was higher without breathing and intracyclic velocity variation was higher while breathing. Swimmers tended to a catch up arm coordination mode for both breathing conditions and a superposition mode when not breathing. These data reflect arm coordination compromising swimming performance, particularly when comparing with non disabled swimmers in literature. The physical and perhaps cognitive impairment associated with Down syndrome may result in a disadvantage in both propulsion and drag, more evident when breathing.

Self-reported physical activity and preaccession fitness testing in U.S. Army applicants.

PubMed

Gubata, Marlene E; Cowan, David N; Bedno, Sheryl A; Urban, Nadia; Niebuhr, David W

2011-08-01

The Assessment of Recruit Motivation and Strength (ARMS) study evaluated a physical fitness screening test for Army applicants before basic training. This report examines applicants' self-reported physical activity as a predictor of objective fitness measured by ARMS. In 2006, the ARMS study administered a fitness test and physical activity survey to Army applicants during their medical evaluation, using multiple logistic regression for comparison. Among both men and women, "qualified" and "exceeds-body-fat" subjects who met American College of Sports Medicine adult physical activity guidelines were more likely to pass the fitness test. Overall, subjects who met physical activity recommendations, watched less television, and played on sports teams had a higher odds of passing the ARMS test after adjustment for age, race, and smoking status. This study demonstrates that self-reported physical activity was associated with physical fitness and may be used to identify those at risk of failing a preaccession fitness test.

Nuclear Energy, Nuclear Weapons Proliferation, and the Arms Race.

ERIC Educational Resources Information Center

Hollander, Jack, Ed.

A symposium was organized to reexamine the realities of vertical proliferation between the United States and the Soviet Union and to place into perspective the horizontal proliferation of nuclear weapons throughout the world, including the possible role of commercial nuclear power in facilitating proliferation. The four invited symposium…

The Last Day of Civilization.

ERIC Educational Resources Information Center

Jacobson, Willard J.

1982-01-01

A narrative account of what might occur the first day of a nuclear war is interspersed with facts about the nuclear arms race and about the destructive power of weapons already stockpiled in the United States and the Soviet Union. A plea is made for preserving civilization from such a catastrophe. (PP)

The Lesson of Hiroshima and Nagasaki. Part II: The Present and Future.

ERIC Educational Resources Information Center

Kauffman, George B.

1985-01-01

Part I (SE 537 587) briefly reviewed the scientific discoveries underlying the atomic bomb and its technological development. This part examines the implications of these events for science education. Areas considered include the nuclear arms race, nuclear winter, the Strategic Defense Initiative, and others. (DH)

Nuclear War in High School History Textbooks.

ERIC Educational Resources Information Center

Fleming, Daniel B.

1983-01-01

A review of 19 recently published, secondary-level United States and world history textbooks found only brief coverage of the Hiroshima and Nagasaki (Japan) bombings, slight attention to the arms race and disarmament, and concentration on scientific and technical developments behind the atomic bomb rather than on its effects. (Author/RW)

The Media Agenda-Setting Effect of Concrete versus Abstract Issues.

ERIC Educational Resources Information Center

Yagade, Aileen; Dozier, David M.

1990-01-01

Matches a content analysis sample of "Time" magazine coverage of two "concrete" issues (drug abuse, energy) and two "abstract" issues (nuclear arms race, federal budget deficit) with Gallup poll data over a lengthy period of time. Finds that concreteness increases news media agenda-setting power whereas abstractness…

Gunboat Diplomacy in the South China Sea

DTIC Science & Technology

2012-01-01

Studies Institute, 2011: 1- 329. Sharma, Amol and Jeremy Page and James Hookway and Rachel Pannett “Asia’s New Arms Race,” Wall Street Journal...146 Schofield, Maritime Energy Resources, p. 164. 147 Ibid. p. 165. 148 Amol Sharma and Jeremy Page and James Hookway and Rachel Pannett

Slowing Military Change

DTIC Science & Technology

2008-10-01

existential fear of one’s superpower rival. Nor was the Cold War the only arms race in history: naval rivalry in the late 19th and early 20th centuries...Military Review, July-August 2006; Norman Solomon, “The Bogus Blurring of Terrorism and Insurgency in Iraq,” The Humanist , Vol. 66, No. 2, March-April

Teaching Controversial Materials: Teaching about the Nuclear Issue.

ERIC Educational Resources Information Center

Wall, Joseph

1986-01-01

Describes difficulties encountered in presenting a college course on nuclear weapons and disarmament. Maintains that such courses must strive for a fuller historical account of the arms race, in addition to stressing the humanistic and ethical questions involved. Warns that controversy will arise and concludes that even blind anger is preferable…

Multilateral Disarmament: Conspiracy for Common Sense. Occasional Paper 31.

ERIC Educational Resources Information Center

Stanley, C. Maxwell

This paper outlines the danger of continuing the conventional and nuclear arms races and offers alternatives to ensure both peace and security. There are five major sections to the paper. In the first section, "Mulitlateral Approach," global multilateral accomplishments, regional multilateral activities, and bilateral negotiations are discussed.…

Network intrusion detection by the coevolutionary immune algorithm of artificial immune systems with clonal selection

NASA Astrophysics Data System (ADS)

Salamatova, T.; Zhukov, V.

2017-02-01

The paper presents the application of the artificial immune systems apparatus as a heuristic method of network intrusion detection for algorithmic provision of intrusion detection systems. The coevolutionary immune algorithm of artificial immune systems with clonal selection was elaborated. In testing different datasets the empirical results of evaluation of the algorithm effectiveness were achieved. To identify the degree of efficiency the algorithm was compared with analogs. The fundamental rules based of solutions generated by this algorithm are described in the article.

Gene pyramiding enhances durable blast disease resistance in rice.

PubMed

Fukuoka, Shuichi; Saka, Norikuni; Mizukami, Yuko; Koga, Hironori; Yamanouchi, Utako; Yoshioka, Yosuke; Hayashi, Nagao; Ebana, Kaworu; Mizobuchi, Ritsuko; Yano, Masahiro

2015-01-14

Effective control of blast, a devastating fungal disease of rice, would increase and stabilize worldwide food production. Resistance mediated by quantitative trait loci (QTLs), which usually have smaller individual effects than R-genes but confer broad-spectrum or non-race-specific resistance, is a promising alternative to less durable race-specific resistance for crop improvement, yet evidence that validates the impact of QTL combinations (pyramids) on the durability of plant disease resistance has been lacking. Here, we developed near-isogenic experimental lines representing all possible combinations of four QTL alleles from a durably resistant cultivar. These lines enabled us to evaluate the QTLs singly and in combination in a homogeneous genetic background. We present evidence that pyramiding QTL alleles, each controlling a different response to M. oryzae, confers strong, non-race-specific, environmentally stable resistance to blast disease. Our results suggest that this robust defence system provides durable resistance, thus avoiding an evolutionary "arms race" between a crop and its pathogen.

Rejection as a call to arms: inter-racial hostility and support for political action as outcomes of race-based rejection in majority and minority groups.

PubMed

Barlow, Fiona Kate; Sibley, Chris G; Hornsey, Matthew J

2012-03-01

Both majority and minority group members fear race-based rejection, and respond by disparaging the groups that they expect will reject them. It is not clear, however, how this process differs in minority and majority groups. Using large representative samples of White (N= 4,618) and Māori (N= 1,163) New Zealanders, we found that perceptions of race-based rejection predicted outgroup negativity in both groups, but in different ways and for different reasons. For White (but not Māori) New Zealanders, increased intergroup anxiety partially mediated the relationship between cognitions of rejection and outgroup negativity. Māori who expected to be rejected on the basis of their race reported increased ethnic identification and, in part through this, increased support for political action benefiting their own group. This finding supports collective-action models of social change in historically disadvantaged minority groups. © 2011 The British Psychological Society.

Discovery and characterization of two new stem rust resistance genes in Aegilops sharonensis.

PubMed

Yu, Guotai; Champouret, Nicolas; Steuernagel, Burkhard; Olivera, Pablo D; Simmons, Jamie; Williams, Cole; Johnson, Ryan; Moscou, Matthew J; Hernández-Pinzón, Inmaculada; Green, Phon; Sela, Hanan; Millet, Eitan; Jones, Jonathan D G; Ward, Eric R; Steffenson, Brian J; Wulff, Brande B H

2017-06-01

We identified two novel wheat stem rust resistance genes, Sr-1644-1Sh and Sr-1644-5Sh in Aegilops sharonensis that are effective against widely virulent African races of the wheat stem rust pathogen. Stem rust is one of the most important diseases of wheat in the world. When single stem rust resistance (Sr) genes are deployed in wheat, they are often rapidly overcome by the pathogen. To this end, we initiated a search for novel sources of resistance in diverse wheat relatives and identified the wild goatgrass species Aegilops sharonesis (Sharon goatgrass) as a rich reservoir of resistance to wheat stem rust. The objectives of this study were to discover and map novel Sr genes in Ae. sharonensis and to explore the possibility of identifying new Sr genes by genome-wide association study (GWAS). We developed two biparental populations between resistant and susceptible accessions of Ae. sharonensis and performed QTL and linkage analysis. In an F 6 recombinant inbred line and an F 2 population, two genes were identified that mapped to the short arm of chromosome 1S sh , designated as Sr-1644-1Sh, and the long arm of chromosome 5S sh , designated as Sr-1644-5Sh. The gene Sr-1644-1Sh confers a high level of resistance to race TTKSK (a member of the Ug99 race group), while the gene Sr-1644-5Sh conditions strong resistance to TRTTF, another widely virulent race found in Yemen. Additionally, GWAS was conducted on 125 diverse Ae. sharonensis accessions for stem rust resistance. The gene Sr-1644-1Sh was detected by GWAS, while Sr-1644-5Sh was not detected, indicating that the effectiveness of GWAS might be affected by marker density, population structure, low allele frequency and other factors.

Computational Analysis of Residue Interaction Networks and Coevolutionary Relationships in the Hsp70 Chaperones: A Community-Hopping Model of Allosteric Regulation and Communication

PubMed Central

Stetz, Gabrielle; Verkhivker, Gennady M.

2017-01-01

Allosteric interactions in the Hsp70 proteins are linked with their regulatory mechanisms and cellular functions. Despite significant progress in structural and functional characterization of the Hsp70 proteins fundamental questions concerning modularity of the allosteric interaction networks and hierarchy of signaling pathways in the Hsp70 chaperones remained largely unexplored and poorly understood. In this work, we proposed an integrated computational strategy that combined atomistic and coarse-grained simulations with coevolutionary analysis and network modeling of the residue interactions. A novel aspect of this work is the incorporation of dynamic residue correlations and coevolutionary residue dependencies in the construction of allosteric interaction networks and signaling pathways. We found that functional sites involved in allosteric regulation of Hsp70 may be characterized by structural stability, proximity to global hinge centers and local structural environment that is enriched by highly coevolving flexible residues. These specific characteristics may be necessary for regulation of allosteric structural transitions and could distinguish regulatory sites from nonfunctional conserved residues. The observed confluence of dynamics correlations and coevolutionary residue couplings with global networking features may determine modular organization of allosteric interactions and dictate localization of key mediating sites. Community analysis of the residue interaction networks revealed that concerted rearrangements of local interacting modules at the inter-domain interface may be responsible for global structural changes and a population shift in the DnaK chaperone. The inter-domain communities in the Hsp70 structures harbor the majority of regulatory residues involved in allosteric signaling, suggesting that these sites could be integral to the network organization and coordination of structural changes. Using a network-based formalism of allostery, we introduced a community-hopping model of allosteric communication. Atomistic reconstruction of signaling pathways in the DnaK structures captured a direction-specific mechanism and molecular details of signal transmission that are fully consistent with the mutagenesis experiments. The results of our study reconciled structural and functional experiments from a network-centric perspective by showing that global properties of the residue interaction networks and coevolutionary signatures may be linked with specificity and diversity of allosteric regulation mechanisms. PMID:28095400

Computational Analysis of Residue Interaction Networks and Coevolutionary Relationships in the Hsp70 Chaperones: A Community-Hopping Model of Allosteric Regulation and Communication.

PubMed

Stetz, Gabrielle; Verkhivker, Gennady M

2017-01-01

Allosteric interactions in the Hsp70 proteins are linked with their regulatory mechanisms and cellular functions. Despite significant progress in structural and functional characterization of the Hsp70 proteins fundamental questions concerning modularity of the allosteric interaction networks and hierarchy of signaling pathways in the Hsp70 chaperones remained largely unexplored and poorly understood. In this work, we proposed an integrated computational strategy that combined atomistic and coarse-grained simulations with coevolutionary analysis and network modeling of the residue interactions. A novel aspect of this work is the incorporation of dynamic residue correlations and coevolutionary residue dependencies in the construction of allosteric interaction networks and signaling pathways. We found that functional sites involved in allosteric regulation of Hsp70 may be characterized by structural stability, proximity to global hinge centers and local structural environment that is enriched by highly coevolving flexible residues. These specific characteristics may be necessary for regulation of allosteric structural transitions and could distinguish regulatory sites from nonfunctional conserved residues. The observed confluence of dynamics correlations and coevolutionary residue couplings with global networking features may determine modular organization of allosteric interactions and dictate localization of key mediating sites. Community analysis of the residue interaction networks revealed that concerted rearrangements of local interacting modules at the inter-domain interface may be responsible for global structural changes and a population shift in the DnaK chaperone. The inter-domain communities in the Hsp70 structures harbor the majority of regulatory residues involved in allosteric signaling, suggesting that these sites could be integral to the network organization and coordination of structural changes. Using a network-based formalism of allostery, we introduced a community-hopping model of allosteric communication. Atomistic reconstruction of signaling pathways in the DnaK structures captured a direction-specific mechanism and molecular details of signal transmission that are fully consistent with the mutagenesis experiments. The results of our study reconciled structural and functional experiments from a network-centric perspective by showing that global properties of the residue interaction networks and coevolutionary signatures may be linked with specificity and diversity of allosteric regulation mechanisms.

Greasy tactics in the plant-pathogen molecular arms race.

PubMed

Boyle, Patrick C; Martin, Gregory B

2015-03-01

The modification of proteins by the attachment of fatty acids is a targeting tactic involved in mechanisms of both plant immunity and bacterial pathogenesis. The plant plasma membrane (PM) is a key battleground in the war against disease-causing microbes. This membrane is armed with an array of sensor proteins that function as a surveillance system to detect invading pathogens. Several of these sensor proteins are directed to the plasma membrane through the covalent addition of fatty acids, a process termed fatty acylation. Phytopathogens secrete effector proteins into the plant cell to subvert these surveillance mechanisms, rendering the host susceptible to infection. The targeting of effectors to specific locales within plant cells, particularly the internal face of the host PM, is critical for their virulence function. Several bacterial effectors hijack the host fatty acylation machinery to be modified and directed to this contested locale. To find and fight these fatty acylated effectors the plant leverages lipid-modified intracellular sensors. This review provides examples featuring how fatty acylation is a battle tactic used by both combatants in the molecular arms race between plants and pathogens. Also highlighted is the exploitation of a specific form of host-mediated fatty acid modification, which appears to be exclusively employed by phytopathogenic effector proteins. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Whip Rule Breaches in a Major Australian Racing Jurisdiction: Welfare and Regulatory Implications

PubMed Central

Hood, Jennifer; McDonald, Carolyn; Wilson, Bethany; McManus, Phil; McGreevy, Paul

2017-01-01

Simple Summary An evidence-based analysis of whip rule breaches in horse racing is needed to address community expectations that racehorses are treated humanely. The study provides the first peer-reviewed characterisation of whip rule breaches and their regulatory outcomes in horseracing, and considers the relationship between rules affecting racing integrity and the welfare of racehorses in a major Australian racing jurisdiction. Abstract Whip use in horseracing is increasingly being questioned on ethical, animal welfare, social sustainability, and legal grounds. Despite this, there is weak evidence for whip use and its regulation by Stewards in Australia. To help address this, we characterised whip rule breaches recorded by Stewards using Stewards Reports and Race Diaries from 2013 and 2016 in New South Wales (NSW) and the Australian Capital Territory (ACT). There were more recorded breaches at Metropolitan (M) than Country (C) or Provincial (P) locations, and by riders of horses that finished first, second, or third than by riders of horses that finished in other positions. The most commonly recorded breaches were forehand whip use on more than five occasions before the 100-metre (m) mark (44%), and whip use that raises the jockey’s arm above shoulder height (24%). It is recommended that racing compliance data be analysed annually to inform the evidence-base for policy, education, and regulatory change, and ensure the welfare of racehorses and racing integrity. PMID:28275207

An Improved Co-evolutionary Particle Swarm Optimization for Wireless Sensor Networks with Dynamic Deployment

PubMed Central

Wang, Xue; Wang, Sheng; Ma, Jun-Jie

2007-01-01

The effectiveness of wireless sensor networks (WSNs) depends on the coverage and target detection probability provided by dynamic deployment, which is usually supported by the virtual force (VF) algorithm. However, in the VF algorithm, the virtual force exerted by stationary sensor nodes will hinder the movement of mobile sensor nodes. Particle swarm optimization (PSO) is introduced as another dynamic deployment algorithm, but in this case the computation time required is the big bottleneck. This paper proposes a dynamic deployment algorithm which is named “virtual force directed co-evolutionary particle swarm optimization” (VFCPSO), since this algorithm combines the co-evolutionary particle swarm optimization (CPSO) with the VF algorithm, whereby the CPSO uses multiple swarms to optimize different components of the solution vectors for dynamic deployment cooperatively and the velocity of each particle is updated according to not only the historical local and global optimal solutions, but also the virtual forces of sensor nodes. Simulation results demonstrate that the proposed VFCPSO is competent for dynamic deployment in WSNs and has better performance with respect to computation time and effectiveness than the VF, PSO and VFPSO algorithms.

The co-evolutionary dynamics of directed network of spin market agents

NASA Astrophysics Data System (ADS)

Horváth, Denis; Kuscsik, Zoltán; Gmitra, Martin

2006-09-01

The spin market model [S. Bornholdt, Int. J. Mod. Phys. C 12 (2001) 667] is generalized by employing co-evolutionary principles, where strategies of the interacting and competitive traders are represented by local and global couplings between the nodes of dynamic directed stochastic network. The co-evolutionary principles are applied in the frame of Bak-Sneppen self-organized dynamics [P. Bak, K. Sneppen, Phys. Rev. Lett. 71 (1993) 4083] that includes the processes of selection and extinction actuated by the local (node) fitness. The local fitness is related to orientation of spin agent with respect to the instant magnetization. The stationary regime is formed due to the interplay of self-organization and adaptivity effects. The fat tailed distributions of log-price returns are identified numerically. The non-trivial model consequence is the evidence of the long time market memory indicated by the power-law range of the autocorrelation function of volatility with exponent smaller than one. The simulations yield network topology with broad-scale node degree distribution characterized by the range of exponents 1.3<γin<3 coinciding with social networks.

The arms race at a time of decision

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rotblat, J.; Pascolini, A.

1984-01-01

This book contains thirty-one articles by leading scientists and scholars form East and West presented at the 33rd Pugwash Conference held in Venice in 1983. The contributors provide research findings and recommendations on such topics as space militarization, nuclear strategy and safety, European security, regional security, and the security of the Third World.

Catalog: Wilmington College Peace Resource Center. Revised Edition.

ERIC Educational Resources Information Center

Wilmington Coll., OH. Peace Resource Center.

A bibliography of low-cost peace education resources for individuals and organizations, this catalogue lists audio-visual materials, archival materials, and books. The audio-visual materials and the books are grouped into some or all of the following categories: atomic bombings, nuclear war, the arms race, anti-war, civil defense, peace education,…

Missile Defense: LBJ's Bid To Curb Arms Race Gains Support.

PubMed

Carter, L J

1967-04-14

In the article of 31 March on antiballistic missile defense, the last sentence of paragraph 2, p. 1654, should read: "Manpower for producing . . . but the outer limit would be about 200,000, or half the number of contractor employees and civil servants working for NASA at the peak of the Apollo program."

Funding the Arms Race: A Case Study of Student Athletic Fees

ERIC Educational Resources Information Center

Denhart, Matthew; Ridpath, David

2011-01-01

Intercollegiate athletics (ICA) is becoming an increasingly expensive venture at America's colleges and universities. Some big-time athletic powers have athletic budgets exceeding $100 million annually, and even schools with lesser reputations in the NCAA's Divisions II and III have had sharp increases in athletic budgets in recent years.…

75 FR 78676 - Proposed Information Collection; Comment Request; Current Population Survey (CPS) Basic...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-16

... age, marital status, gender, Armed Forces status, education, race, origin, and family income. We use... sponsor the basic monthly survey. The Census Bureau also prepares and conducts all the field work. At the.... Some of the information within that portion includes employment status, number of hours worked, job...

78 FR 77646 - Proposed Information Collection; Comment Request; Current Population Survey (CPS) Basic...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-24

... age, marital status, gender, Armed Forces status, education, race, origin, and family income. We use... sponsor the basic monthly survey. The Census Bureau also prepares and conducts all the field work. At the.... Some of the information within that portion includes employment status, number of hours worked, job...

Relating Peace Education and Social Studies in an Age of Insecurity.

ERIC Educational Resources Information Center

Carson, Terry

1985-01-01

In the theme of insecurity there is a potential for peace education to address social education. Insecurity underpins the arms race and lies at the root of the growing cycle of violence. Peace education must help students understand the forms of structural injustices that preserve inequities and breed violence. (RM)

Nuclear Dangers: A Resource Guide for Secondary School Teachers. Teaching Nuclear Issues.

ERIC Educational Resources Information Center

Meier, Paulette; McPherson, Beth

Provided in this guide are annotated lists of teacher and student resources for teaching and learning about nuclear issues in the secondary school. Resources are grouped into five major sections. The first section (background reading for teachers) contains books and articles focusing on nuclear issues (nuclear war; arms race/disarmament; nuclear…

Inching toward Armageddon: a psychiatric view.

PubMed

Abraham, H D

1983-01-01

The existence of thermonuclear arsenals capable of destroying much of humanity takes its origins from, and has an influence on, processes that are largely psychological. The threat to use a single nuclear bomb to resolve contemporary conflict is an anathema in part because complex nation-states did not evolve with surviving a nuclear war in mind. The atomic arms race has proceeded apace because of maladaptive psychological mechanism including denial, distortion, projection, and, most relevantly, the need to enhance bonding within groups by creating stereotypes. One consequence of the arms race is a climate of fear and hopelessness, and especially destructive effect of which is seen in children. The physician's role in the prevention of nuclear war is critical, but divided between contradictory roles. On one hand, the physician is traditionally identified as a non-political advocate of the sick; on the other, as an advocate for the public health. It is this second model that enables physicians most legitimately to work for the prevention of nuclear war and to deal with the psychiatric concomitants of a planet drifting toward disaster.

Inching toward Armageddon: a psychiatric view.

PubMed Central

Abraham, H. D.

1983-01-01

The existence of thermonuclear arsenals capable of destroying much of humanity takes its origins from, and has an influence on, processes that are largely psychological. The threat to use a single nuclear bomb to resolve contemporary conflict is an anathema in part because complex nation-states did not evolve with surviving a nuclear war in mind. The atomic arms race has proceeded apace because of maladaptive psychological mechanism including denial, distortion, projection, and, most relevantly, the need to enhance bonding within groups by creating stereotypes. One consequence of the arms race is a climate of fear and hopelessness, and especially destructive effect of which is seen in children. The physician's role in the prevention of nuclear war is critical, but divided between contradictory roles. On one hand, the physician is traditionally identified as a non-political advocate of the sick; on the other, as an advocate for the public health. It is this second model that enables physicians most legitimately to work for the prevention of nuclear war and to deal with the psychiatric concomitants of a planet drifting toward disaster. PMID:6636836

Task 1.6 -- Mixed waste. Topical report, April 1994--September 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rindt, J.R.; Jones, F.A.

1996-01-01

For fifty years, the United States was involved in a nuclear arms race of immense proportions. During the majority of this period, the push was always to design new weapons, produce more weapons, and increase the size of the arsenal, maintaining an advantage over the opposition in order to protect US interests. Now that the Cold War is over, the US is faced with the imposing tasks of dismantling, cleaning up, and remediating the wide variety of problems created by this arms race. The ability to understand the problems encountered when dealing with radioactive waste, both from a scientific standpointmore » and from a legislative standpoint, requires knowledge of treatment and disposal subject areas. This required the accumulation of applicable information. A literature database was developed; site visits were made; and contact relationships were established. Informational databases from government agencies involved in environmental remediation were ordered or purchased, and previously established private sector relationships were used to develop an information base. An appendix contains 482 bibliographic citations that have been integrated into a Microsoft Access{reg_sign} database.« less

The UDP-glycosyltransferase (UGT) superfamily expressed in humans, insects and plants: Animal-plant arms-race and co-evolution.

PubMed

Bock, Karl Walter

2016-01-01

UDP-glycosyltransferases (UGTs) are major phase II enzymes of a detoxification system evolved in all kingdoms of life. Lipophilic endobiotics such as hormones and xenobiotics including phytoalexins and drugs are conjugated by vertebrates mainly with glucuronic acid, by invertebrates and plants mainly with glucose. Plant-herbivore arms-race has been the major driving force for evolution of large UGT and other enzyme superfamilies. The UGT superfamily is defined by a common protein structure and signature sequence of 44 amino acids responsible for binding the UDP moiety of the sugar donor. Plants developed toxic phytoalexins stored as glucosides. Upon herbivore attack these conjugates are converted to highly reactive compounds. In turn, animals developed large families of UGTs in their intestine and liver to detoxify these phytoalexins. Interestingly, phytoalexins, exemplified by quercetin glucuronides and glucosinolate-derived isocyanates, are known insect attractant pigments in plants, and antioxidants, anti-inflammatory and chemopreventive compounds of humans. It is to be anticipated that phytochemicals may provide a rich source in beneficial drugs. Copyright © 2015. Published by Elsevier Inc.

Incidence of herpes simplex virus type 2 infection in 5 sexually transmitted disease (STD) clinics and the effect of HIV/STD risk-reduction counseling.

PubMed

Gottlieb, Sami L; Douglas, John M; Foster, Mark; Schmid, D Scott; Newman, Daniel R; Baron, Anna E; Bolan, Gail; Iatesta, Michael; Malotte, C Kevin; Zenilman, Jonathan; Fishbein, Martin; Peterman, Thomas A; Kamb, Mary L

2004-09-15

The seroincidence of herpes simplex virus type 2 (HSV-2) infection was determined among 1766 patients attending sexually transmitted disease (STD) clinics and enrolled in a randomized, controlled trial of human immunodeficiency virus (HIV)/STD risk-reduction counseling (RRC). Arm 1 received enhanced RRC (4 sessions); arm 2, brief RRC (2 sessions); and arm 3, the control arm, brief informational messages. The overall incidence rate was 11.7 cases/100 person-years (py). Independent predictors of incidence of HSV-2 infection included female sex; black race; residence in Newark, New Jersey; <50% condom use with an occasional partner; and, in females, incident trichomoniasis and bacterial vaginosis. Only 10.8% of new HSV-2 infections were diagnosed clinically. Incidence rates were 12.9 cases/100 py in the control arm, 11.8 cases/100 py in arm 2, and 10.3 cases/100 py in arm 1 (hazard ratio, 0.8 [95% confidence interval, 0.6-1.1], vs. controls). The possible benefit of RRC in preventing acquisition of HSV-2 infection offers encouragement that interventions more specifically tailored to genital herpes may be useful and should be an important focus of future studies.

Deception and Manipulation: The Arms of Leishmania, a Successful Parasite

PubMed Central

Cecílio, Pedro; Pérez-Cabezas, Begoña; Santarém, Nuno; Maciel, Joana; Rodrigues, Vasco; Cordeiro da Silva, Anabela

2014-01-01

Leishmania spp. are intracellular parasitic protozoa responsible for a group of neglected tropical diseases, endemic in 98 countries around the world, called leishmaniasis. These parasites have a complex digenetic life cycle requiring a susceptible vertebrate host and a permissive insect vector, which allow their transmission. The clinical manifestations associated with leishmaniasis depend on complex interactions between the parasite and the host immune system. Consequently, leishmaniasis can be manifested as a self-healing cutaneous affliction or a visceral pathology, being the last one fatal in 85–90% of untreated cases. As a result of a long host–parasite co-evolutionary process, Leishmania spp. developed different immunomodulatory strategies that are essential for the establishment of infection. Only through deception and manipulation of the immune system, Leishmania spp. can complete its life cycle and survive. The understanding of the mechanisms associated with immune evasion and disease progression is essential for the development of novel therapies and vaccine approaches. Here, we revise how the parasite manipulates cell death and immune responses to survive and thrive in the shadow of the immune system. PMID:25368612

Fluid intake and changes in limb volumes in male ultra-marathoners: does fluid overload lead to peripheral oedema?

PubMed

Bracher, Alexia; Knechtle, Beat; Gnädinger, Markus; Bürge, Jolanda; Rüst, Christoph Alexander; Knechtle, Patrizia; Rosemann, Thomas

2012-03-01

An increase in body mass due to oedema has been previously described. The aim of this study was to investigate a potential association between both fluid and electrolyte intake and the formation of peripheral oedemas. Fluid and electrolyte intakes and the changes in limb volumes in 50 male 100-km ultra-marathoners were measured. Pre- and post-race serum sodium concentration ([Na(+)]), serum aldosterone concentration, serum copeptin concentration, serum and urine osmolality and body mass were determined. Fluid intake, renal function parameters and urinary output, as well as the changes of volume in the extremities, were measured. The changes of volume in the limbs were measured using plethysmography. Serum [Na(+)] increased by 1.6%; body mass decreased by 1.9 kg. Serum copeptin and aldosterone concentrations were increased. The change in serum copeptin concentration and the change in serum [Na(+)] correlated positively; the change in serum [Na(+)] and body mass correlated negatively. A mean fluid intake of 0.58 L/h was positively related to running speed and negatively to post-race serum [Na(+)]. Total fluid intake was positively related to the changes in both arm and lower leg volumes. Running speed was positively associated with the changes in arm and lower leg volumes; race time was related to the changes in serum copeptin or aldosterone concentrations. To conclude, fluid intake was related to the changes in limb volumes, where athletes with an increased fluid intake developed an increase in limb volumes.

Disarming the Red Queen: plant invasions, novel weapons, species coexistence, and microevolution

USDA-ARS?s Scientific Manuscript database

This paper is a commentary on the importance of the featured paper in the issue. The authors found that an invasive species and a co-occurring native species had evolved to coexist with one another in the space of 50 years. The rapid evolution of tolerance (as opposed to arms race style escalation) ...

An Athletic Arms Race

ERIC Educational Resources Information Center

Budig, Gene A.

2007-01-01

Myles Brand is a person of unquestioned integrity and high principle. As president of the National Collegiate Athletic Association (NCAA), he has been asked to fend off an unruly mob with a switch. In the present environment for collegiate sports, his chances for success are slight, at best. What Brand and the NCAA face today is a very real "arms…

Crossroads: Quality of Life in a Nuclear World. A High School Science Curriculum.

ERIC Educational Resources Information Center

French, Dan; Phillips, Connie

One of a set of high school curricula on nuclear issues, this 10-day science unit helps students understand the interrelationship between the economy, the arms race, military spending, and the threat of nuclear war. Through activities such as role playing, discussion, brainstorming, and problem solving, students develop their ability to evaluate…

Crossroads: Quality of Life in a Nuclear World. A High School Social Studies Curriculum.

ERIC Educational Resources Information Center

French, Dan; And Others

One of a set of high school curricula on nuclear issues, this 10-day social studies unit helps students understand the interrelationship of economics, the arms race, military spending, and the threat of nuclear war. Activities such as role plays, discussion, brainstorming, and problem solving develop students' abilities to evaluate issues and…

Crossroads: Quality of Life in a Nuclear World. A High School English Curriculum.

ERIC Educational Resources Information Center

French, Dan; And Others

One of a set of high school curricula on nuclear issues, this 10-day unit for English classes informs students of the issues surrounding the nuclear arms race and military spending. Each lesson includes readings, worksheets, and a daily homework assignment and focuses on one of the following activities: discussion, brainstorming, role playing, or…

Perceptions of Geography Students in the USA and Egypt on Global Issues

ERIC Educational Resources Information Center

Saleh, Edrees Sultan; Gandy, S. Kay

2015-01-01

The study aimed to compare the perceptions of Egyptian and US students on global issues. The authors developed a survey of global issues and administered it to sample of 321 Geography students in the USA and Egypt. The survey tapped five issues: global citizenship, cultural diversity, global conflicts, nuclear arms race, and global warming. The…

The spitting image of plant defenses: effects of plant secondary chemistry on the efficiency of caterpillar regurgitant as an anti-predator defense

USDA-ARS?s Scientific Manuscript database

In the arms race between plants, herbivores, and their natural enemies, specialized herbivores may use plant defenses for their own benefit. In such cases, variation in secondary chemistry among host plants may affect the benefits that herbivores derive from these defenses. Caterpillars of Pieris br...

On the evolutionary arms-race between Utetheisa ornatrix moth and its Florida host, Crotalaria pumila: chemical attraction, and mechanical defense

USDA-ARS?s Scientific Manuscript database

While Utetheisa ornatrix larvae are able to develop through feeding only on foliage of its hostplants in the genus Crotalaria, in later instars they are attracted to seeds as a richer source of alkaloids. Recently, it was demonstrated that seeds receive different degrees of mechanical protection fro...

Drawing Dissent: Postracialist Pedagogy, Racist Literacy, and Racial Plagiarism in Anti-Obama Political Cartoons

ERIC Educational Resources Information Center

Howard, Philip S. S.

2014-01-01

From the frequency of the racially motivated and racially justified slayings of black youth to the increased popularity of blatantly derisive racist humor, the enactment of race and racism appears to have become more defiantly overt and unapologetic. Consider the slayings of Trayvon Martin, Renisha McBride, and Jordan Davis, whose armed white…

Choices: A Unit on Conflict and Nuclear War.

ERIC Educational Resources Information Center

Massachusetts Teachers Association, Boston.

Ten lessons on the evolution of the nuclear arms race, the nature and consequences of using nuclear weapons, and new ways that conflicts among nations might be resolved are presented for the junior high school level. The unit contains age-appropriate materials to equip students with skills and knowledge to understand what choices can be made to…

The International Politics of Peace Education: The Conflict between Deterrence and Disarmament.

ERIC Educational Resources Information Center

Willers, Jack Conrad

The main impetus for peace education is the arms race, which places peace education in the conflict between conservatives advocating increased nuclear deterrence and liberals supporting nuclear disarmament. In the United States, education for peace is still in its infancy. Other developed nations, such as the Scandinavian countries and to a lesser…

Spending Plenty so Athletes Can Make the Grade

ERIC Educational Resources Information Center

Wolverton, Brad

2008-01-01

This article reports that the facilities arms race in college sports has a new frontier: academic-services buildings. Over the past decade, a dozen major college programs have built stand-alone academic centers, most of them for the exclusive use of athletes. At least seven more colleges are planning new buildings or major renovations in coming…

New Dimensions in Movement and Fitness through Integration

ERIC Educational Resources Information Center

Dean, Blair

2005-01-01

In this article, the author presents a number of ways to integrate academic content with physical activities. Among the activities are: (1) Paint the Alphabet, where students use different body parts (arms, legs, and head) as large paint brushes to paint the entire alphabet on an imaginary canvas; (2) Sequence Race, where students are placed into…

Regional Differences in the Structure of Earnings. Program on Regional and Urban Economics, Discussion Paper No. 66.

ERIC Educational Resources Information Center

Hanushek, Eric A.

Slightly over 180,000 draftees were surveyed 10 months after leaving the military to gain data regarding training, employment, occupation and wages if working, marital status, education, Armed Forces Qualification Test (AFQT) score, age, race, military occupation, and home. Differences in earnings functions among smaller, homogeneous labor markets…

Cyanophages: Starving the Host to Recruit Resources.

PubMed

Kaplan, Aaron

2016-06-20

Phytoplankton and the viruses that infect them are locked in an evolutionary arms race, the nature of which is presently being revealed. A new study shows that cyanophage-mediated inhibition of CO2 fixation enables the phages to recruit photosynthetically formed redox and ATP to fulfill their nucleotide and metabolic demand. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Assessment Arms Race and Its Fallout: High-Stakes Grading and the Case for Slow Scholarship

ERIC Educational Resources Information Center

Harland, Tony; McLean, Angela; Wass, Rob; Miller, Ellen; Sim, Kwong Nui

2015-01-01

This research questions the impact of assessment on university teaching and learning in circumstances where all student work is graded. Sixty-two students and lecturers were interviewed to explore their experiences of assessment at an institution that had adopted a modular course structure and largely unregulated numbers of internal assessments.…

The Responsibility of Adult Educators in the Nuclear Age. TECHNIQUES.

ERIC Educational Resources Information Center

Rosenblum, Sandra; Goldberg, Joan Carol

1984-01-01

The task of adult educators is to provide students with information as well as opportunities to explore alternatives to the arms race. As a starting point to raising nuclear issues in the classroom and incorporating them into the curriculum, the adult educator can administer a survey or questionnaire to students about nuclear weapons and the…

Accidental Nuclear War: The Growing Peril. Part I [and] Part II.

ERIC Educational Resources Information Center

Newcombe, Alan, Ed.

1984-01-01

Two volumes designed to increase awareness of accidental nuclear war dangers are presented. The first of 5 sections in volume I proposes that although accidental war is preventable, the current arms race and secrecy about accidents and false alarms increase the possibility of an accidental war. Section 2 posits that decreased decision-making time…

Enhancing the Effects of "The Day After" with an Educational Intervention.

ERIC Educational Resources Information Center

Slem, Charles M.; Nelson, Linden

The major purpose of this study was to investigate the possible enhancement of the effects of the movie "The Day After" via an educational lecture on the arms race that was given seven days after the movie presentation. Subjects were 370 college students in ten introductory psychology classes. A Nuclear Weapons Policies questionnaire was…

More efficient swimming by spreading your fingers

NASA Astrophysics Data System (ADS)

van de Water, Willem; van Houwelingen, Josje; Willemsen, Dennis; Breugem, Wim Paul; Westerweel, Jerry; Delfos, Rene; Grift, Ernst Jan

2016-11-01

A tantalizing question in free-style swimming is whether the stroke efficiency during the pull phase depends on spreading the fingers. It is a subtle effect-not more than a few percent-but it could make a big difference in a race. We measure the drag of arm models with increasing finger spreading in a wind tunnel and compare forces and moments to the results of immersed boundary simulations. Virtual arms were used in the simulations and their 3D-printed real versions in the experiment. We find an optimal finger spreading, accompanied by a marked increase of coherent vortex shedding. A simple actuator disk model explains this optimum.

Coevolution of Cooperation and Partner Rewiring Range in Spatial Social Networks

NASA Astrophysics Data System (ADS)

Khoo, Tommy; Fu, Feng; Pauls, Scott

2016-11-01

In recent years, there has been growing interest in the study of coevolutionary games on networks. Despite much progress, little attention has been paid to spatially embedded networks, where the underlying geographic distance, rather than the graph distance, is an important and relevant aspect of the partner rewiring process. It thus remains largely unclear how individual partner rewiring range preference, local vs. global, emerges and affects cooperation. Here we explicitly address this issue using a coevolutionary model of cooperation and partner rewiring range preference in spatially embedded social networks. In contrast to local rewiring, global rewiring has no distance restriction but incurs a one-time cost upon establishing any long range link. We find that under a wide range of model parameters, global partner switching preference can coevolve with cooperation. Moreover, the resulting partner network is highly degree-heterogeneous with small average shortest path length while maintaining high clustering, thereby possessing small-world properties. We also discover an optimum availability of reputation information for the emergence of global cooperators, who form distant partnerships at a cost to themselves. From the coevolutionary perspective, our work may help explain the ubiquity of small-world topologies arising alongside cooperation in the real world.

Comparison of the FaroArm Laser Scanner With the MicroScribe Digitizer Using Basicranial Measurements.

PubMed

Vu, Alexander F; Chundury, Rao V; Perry, Julian D

2017-07-01

To compare the results of a mechanical 3-dimensional laser scanner for craniofacial measurements of the basicranium to a validated coordinate device. Access was granted by the Cleveland Natural History Museum to evaluate the Hamann-Todd Human Osteological Collection for this study. The MicroScribe and the FaroArm were used to gather coordinate data of various bony landmarks measurements including the prosthion, staphylion, hormion, and basion. Seventy-three human skulls were measured and scanned. Distances calculated from the coordinates were tested for agreement using the Bland-Altman test. There were no significant differences in the bias or slope measures between the MicroScribe and the FaroArm. In addition to the univariate test for slope significance, multivariable analysis using age, gender, and race as additional predictors showed no significant difference in any variable (P < 0.05). This is the first study demonstrating agreement of the FaroArm in any human skull measurement with the validated MicroScribe digitizer. Compared with the MicroScribe digitizer, the FaroArm allows for 3-dimensional imaging and the ability to store, handle, and view data digitally. Future use of real-time facial measurements using the FaroArm offers potential for improved surgical planning and outcomes.

Learning to Eat: Who Knew the Ivory Tower Had a Kitchen?

ERIC Educational Resources Information Center

Cardone, Kenneth

2009-01-01

Beating the competition with restaurant-style dining, wood-fired pizza ovens, espresso machines and organic vegetables is one of many ways for colleges to attract and hold the best and brightest. It also seems that fond food memories fuel alumni associations, which increase attendance at reunions and boost giving. But is it just an arms race with…

The Role of Test Scores in Explaining Race and Gender Differences in Wages

ERIC Educational Resources Information Center

Blackburn, McKinley L.

2004-01-01

Previous research has suggested that skills reflected in test-score performance on tests such as the Armed Forces Qualification Test (AFQT) can account for some of the racial differences in average wages. I use a more complete set of test scores available with the National Longitudinal Survey of Youth 1979 Cohort to reconsider this evidence, and…

U.S. Overseas Military Presence: What Are the Strategic Choices?

DTIC Science & Technology

2012-01-01

influence in key regions • dissuade military competition and arms races • protect Americans from terrorist attacks • restrict the flow of illegal trade ...1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no...Terrorist Attacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Restrict Flow of Illegal Trade and Ensure Flow of Commerce

Male meiosis and gametogenesis in wild house mice (Mus musculus domesticus) from a chromosomal hybrid zone; a comparison between "simple" Robertsonian heterozygotes and homozygotes.

PubMed

Wallace, B M; Searle, J B; Everett, C A

1992-01-01

Wild male house mice Mus musculus domesticus were collected from the hybrid zone between the John o'Groats race (2n = 32) and the standard race (2n = 40) in northern Scotland. Meiosis in both homozygotes (2n = 32, 36, and 40) and single Robertsonian heterozygotes (2n = 33, 35, and 37) was found to be orderly. At prophase/metaphase I in heterozygotes, a trivalent was formed from the metacentric and two homologous acrocentrics. At pachytene, this trivalent usually had a single side arm at the position of the centromeres, as a result of nonhomologous pairing of the acrocentrics. This side arm persisted into diplotene. Generally only a single chiasma was formed between each acrocentric and the metacentric. Anaphase I nondisjunction frequencies were estimated as 1.5% for the homozygotes and 2.7% for the heterozygotes. The extent of germ cell death between the pachytene and round spermatid stages was 18% greater in heterozygotes than in homozygotes. Our results concur with previous studies which indicate that single Robertsonian heterozygotes in wild house mice have near-normal fertility.

The nuclear present. A guide to recent books on nuclear war, weapons, the peace movement, and related issues, with a chronology of nuclear events, 1789-1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, G.

The Nuclear Present brings the interested reader up-to-date on significant English-language books about nuclear weapons and related topics, identifying primarily important works of nuclear non-fiction that have come out since 1984. Each reference has a paragraph of comment about its subject and value. General organizational areas include the following: Reference Works; Nuclear weapons and Nuclear war (14 sub-headings including overviews, development, effects, tests, arms race, prospectives, legal considerations etc.); Strategy; proliferation; Stratigic Defense; Arms control and disarmament; ethical, pholosophical and religous perspectives; new paths to peace; periodic guide; the Chernobyl Disaster. An extensive Nuclear Chronology (1789-1991) written by the authormore » allows a fairly detailed sense of the historical record of nuclear weapons, including testing, manufacture, use and movements for arms control and disarmament.« less

Impact of Gender, Partner Status, and Race on Locoregional Failure and Overall Survival in Head and Neck Cancer Patients in Three Radiation Therapy Oncology Group Trials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dilling, Thomas J., E-mail: Thomas.Dilling@moffitt.org; Bae, Kyounghwa; Paulus, Rebecca

Purpose: We investigated the impact of race, in conjunction with gender and partner status, on locoregional control (LRC) and overall survival (OS) in three head and neck trials conducted by the Radiation Therapy Oncology Group (RTOG). Methods and Materials: Patients from RTOG studies 9003, 9111, and 9703 were included. Patients were stratified by treatment arms. Covariates of interest were partner status (partnered vs. non-partnered), race (white vs. non-white), and sex (female vs. male). Chi-square testing demonstrated homogeneity across treatment arms. Hazards ratio (HR) was used to estimate time to event outcome. Unadjusted and adjusted HRs were calculated for all covariatesmore » with associated 95% confidence intervals (CIs) and p values. Results: A total of 1,736 patients were analyzed. Unpartnered males had inferior OS rates compared to partnered females (adjusted HR = 1.22, 95% CI, 1.09-1.36), partnered males (adjusted HR = 1.20, 95% CI, 1.09-1.28), and unpartnered females (adjusted HR = 1.20, 95% CI, 1.09-1.32). White females had superior OS compared with white males, non-white females, and non-white males. Non-white males had inferior OS compared to white males. Partnered whites had improved OS relative to partnered non-white, unpartnered white, and unpartnered non-white patients. Unpartnered males had inferior LRC compared to partnered males (adjusted HR = 1.26, 95% CI, 1.09-1.46) and unpartnered females (adjusted HR = 1.30, 95% CI, 1.05-1.62). White females had LRC superior to non-white males and females. White males had improved LRC compared to non-white males. Partnered whites had improved LRC compared to partnered and unpartnered non-white patients. Unpartnered whites had improved LRC compared to unpartnered non-whites. Conclusions: Race, gender, and partner status had impacts on both OS and locoregional failure, both singly and in combination.« less

Racial and Ethnic Disparities in Parental Refusal of Consent in a Large, Multisite Pediatric Critical Care Clinical Trial.

PubMed

Natale, Joanne E; Lebet, Ruth; Joseph, Jill G; Ulysse, Christine; Ascenzi, Judith; Wypij, David; Curley, Martha A Q

2017-05-01

To evaluate whether race or ethnicity was independently associated with parental refusal of consent for their child's participation in a multisite pediatric critical care clinical trial. We performed a secondary analyses of data from Randomized Evaluation of Sedation Titration for Respiratory Failure (RESTORE), a 31-center cluster randomized trial of sedation management in critically ill children with acute respiratory failure supported on mechanical ventilation. Multivariable logistic regression modeling estimated associations between patient race and ethnicity and parental refusal of study consent. Among the 3438 children meeting enrollment criteria and approached for consent, 2954 had documented race/ethnicity of non-Hispanic White (White), non-Hispanic Black (Black), or Hispanic of any race. Inability to approach for consent was more common for parents of Black (19.5%) compared with White (11.7%) or Hispanic children (13.2%). Among those offered consent, parents of Black (29.5%) and Hispanic children (25.9%) more frequently refused consent than parents of White children (18.2%, P < .0167 for each). Compared with parents of White children, parents of Black (OR 2.15, 95% CI 1.56-2.95, P < .001) and Hispanic (OR 1.44, 95% CI 1.10-1.88, P = .01) children were more likely to refuse consent. Parents of children offered participation in the intervention arm were more likely to refuse consent than parents in the control arm (OR 2.15, 95% CI 1.37-3.36, P < .001). Parents of Black and Hispanic children were less likely to be approached for, and more frequently declined consent for, their child's participation in a multisite critical care clinical trial. Ameliorating this racial disparity may improve the validity and generalizability of study findings. ClinicalTrials.gov: NCT00814099. Copyright © 2017 Elsevier Inc. All rights reserved.

New Metacentric Populations and Phylogenetic Hypotheses Involving Whole-Arm Reciprocal Translocation in Mus musculus domesticus from Sicily, Southern Italy.

PubMed

Castiglia, Riccardo; Capanna, Ernesto; Bezerra, Alexandra M R; Bizzoco, Domenico; Zambigli, Emanuela; Solano, Emanuela

2015-01-01

The house mouse Mus musculus domesticus is characterized by more than 100 metacentric populations, due to the occurrence of Robertsonian (Rb) fusions, together with the standard all-telocentric karyotype (2n = 40). We examined G-banded karyotypes of 18 mice from 10 localities in Sicily and describe 3 new metacentric populations: 'Ragusa Ibla' (IRAG), 2n = 33-36, Rb(2.4), Rb(5.6), Rb(9.16), Rb(13.17); 'Piana degli Albanesi' (IPIA), 2n = 23, Rb(1.18), Rb(2.15), Rb(3.5), Rb(4.12), Rb(6.11), Rb(7.8), Rb(9.16), Rb(10.14), Rb(13.17); 'Trapani' (ITRA), 2n = 22, Rb(1.18), Rb(2.15), Rb(3.7), Rb(4.12), Rb(5.9), Rb(6.11), Rb(8.16), Rb(10.14), Rb(13.17). Three mice belonged to the previously reported 'Castelbuono' race (ICAS), 2n = 24, which is very similar to the nearby 'Palermo' (IPAL) race, 2n = 26. Three Rb fusions not yet observed in wild mouse populations were identified: Rb(3.5), Rb(3.7) and Rb(5.9). Rb fusions shared among 4 races (IPIA, IRAG, ICAS, and IPAL) allowed us to describe their potential phylogenetic relationships. We obtained 2 alternative phylogenetic trees. The differences between them are mainly due to various modes of formation of IPIA and ITRA. In the first hypothesis, the specific Rb fusions occurred independently. In the second, those of IRAG originated from those of IPIA via whole-arm reciprocal translocations. © 2015 S. Karger AG, Basel.

Dangerous Enough: Moderating Racial Bias with Contextual Threat Cues

PubMed Central

Correll, Joshua; Wittenbrink, Bernd; Park, Bernadette; Judd, Charles M.; Goyle, Arina

2010-01-01

Research shows that participants shoot armed Blacks more frequently and quickly than armed Whites, but make don’t-shoot responses more frequently and quickly for unarmed Whites than unarmed Blacks. We argue that this bias reflects the perception of threat – specifically, threat associated with Black males. Other danger cues (not just race) may create a similar predisposition to shoot, and if these cues promote shooting when the target is White, they should attenuate racial bias. We embedded targets in threatening andsafe backgrounds. Racial bias was evident in safe contexts but disappeared when context signaled danger, and this reduction was largely due to an increased tendency to shoot White targets. PMID:21344058

Coevolutionary, coexisting learning and teaching agents model for prisoner’s dilemma games enhancing cooperation with assortative heterogeneous networks

NASA Astrophysics Data System (ADS)

Tanimoto, Jun

2013-07-01

Unlike other natural network systems, assortativity can be observed in most human social networks, although it has been reported that a social dilemma situation represented by the prisoner’s dilemma favors dissortativity to enhance cooperation. We established a new coevolutionary model for both agents’ strategy and network topology, where teaching and learning agents coexist. Remarkably, this model enables agents’ enhancing cooperation more than a learners-only model on a time-frozen scale-free network and produces an underlying assortative network with a fair degree of power-law distribution. The model may imply how and why assortative networks are adaptive in human society.

Influence of anthropometry on race performance in extreme endurance triathletes: World Challenge Deca Iron Triathlon 2006

PubMed Central

Knechtle, Beat; Knechtle, Patrizia; Andonie, Jorge Luis; Kohler, Götz

2007-01-01

Objective To investigate the influence of anthropometric variables on race performance in ultra‐endurance triathletes in an ultra‐triathlon. Design Descriptive field study. Setting The “World Challenge Deca Iron Triathlon 2006” in Monterrey, Mexico, in which everyday for 10 consecutive days athletes had to perform the distance of one Ironman triathlon of 3.8 km swimming, 180 km cycling and 42.195 km running. Subjects Eight male ultra‐endurance athletes (mean (SD) age 40.6 (10.7) years, weight 76.4 (8.4) kg, height 175 (4) cm and body mass index (BMI) 24.7 (2.2) kg/m2). Interventions None. Main outcome measures Direct measurement of body mass, height, leg length, skinfold thicknesses, limb circumference and calculation of BMI, skeletal muscle mass (SM), percentage SM (%SM) and percentage body fat (%BF) in order to correlate measured and calculated anthropometric variables with race performance. Results Race time was not significantly (p>0.05) influenced by the directly measured variables, height, leg length, body mass, average skinfold thicknesses, or circumference of thigh, calf or upper arm. Furthermore, no significant (p>0.05) correlation was observed between race time and the calculated variables, BMI, %SM and %BF. Conclusions In a multistage ultra‐triathlon over 10 Ironman triathlon distances in 10 consecutive days, there was no effect of body mass, height, leg length, skinfold thicknesses, limb circumference, BMI, %SM or %BF on race performance in the only eight finishers. PMID:17556527

Corporate interests, philanthropies, and the peace movement.

PubMed

Wright, T; Rodriguez, F; Waitzkin, H

1986-01-01

Corporate and philanthropic involvement in the peace movement is growing. In considering medical peace groups as examples, we have studied the ways that corporate and philanthropic funding have shaped the course of activism. Our methods have included: review of the Foundations Grant Index from 1974-1983; analysis of corporations' and foundations' criteria for grants in the categories of peace, arms control, and disarmament; interviews with leaders of activist organizations and with foundation officials; and our own experiences in the peace movement. Corporate interests in preventing nuclear war stem from a concern for global stability in which world markets may expand, and from a hope to frame issues posed by the peace movement in a way that will not challenge basic structures of power and finance. Several general features make peace groups respectable and attractive to philanthropies; an uncritical stance toward corporate participation in the arms race; a viewpoint that the main danger of nuclear war stems from a profound, bilateral conflict between the United States and the Soviet Union; and a single-issue focus that does not deal with the many related problems reflecting the injustices of capitalism. The two major medical groups working for peace, Physicians for Social Responsibility (PSR) and International Physicians for the Prevention of Nuclear War (IPPNW), have accomplished many goals; however, their adherence to subtle criteria of respectability and their dependence on philanthropic funding have limited the scope of their activism. The struggle for peace can not succeed without fundamental changes in the corporate system that initiates, maintains, and promotes the arms race.

Cyber Security Research Frameworks For Coevolutionary Network Defense

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rush, George D.; Tauritz, Daniel Remy

Several architectures have been created for developing and testing systems used in network security, but most are meant to provide a platform for running cyber security experiments as opposed to automating experiment processes. In the first paper, we propose a framework termed Distributed Cyber Security Automation Framework for Experiments (DCAFE) that enables experiment automation and control in a distributed environment. Predictive analysis of adversaries is another thorny issue in cyber security. Game theory can be used to mathematically analyze adversary models, but its scalability limitations restrict its use. Computational game theory allows us to scale classical game theory to larger,more » more complex systems. In the second paper, we propose a framework termed Coevolutionary Agent-based Network Defense Lightweight Event System (CANDLES) that can coevolve attacker and defender agent strategies and capabilities and evaluate potential solutions with a custom network defense simulation. The third paper is a continuation of the CANDLES project in which we rewrote key parts of the framework. Attackers and defenders have been redesigned to evolve pure strategy, and a new network security simulation is devised which specifies network architecture and adds a temporal aspect. We also add a hill climber algorithm to evaluate the search space and justify the use of a coevolutionary algorithm.« less

Archaeogenomic insights into the adaptation of plants to the human environment: pushing plant-hominin co-evolution back to the Pliocene.

PubMed

Allaby, Robin G; Kistler, Logan; Gutaker, Rafal M; Ware, Roselyn; Kitchen, James L; Smith, Oliver; Clarke, Andrew C

2015-02-01

The colonization of the human environment by plants, and the consequent evolution of domesticated forms is increasingly being viewed as a co-evolutionary plant-human process that occurred over a long time period, with evidence for the co-evolutionary relationship between plants and humans reaching ever deeper into the hominin past. This developing view is characterized by a change in emphasis on the drivers of evolution in the case of plants. Rather than individual species being passive recipients of artificial selection pressures and ultimately becoming domesticates, entire plant communities adapted to the human environment. This evolutionary scenario leads to systems level genetic expectations from models that can be explored through ancient DNA and Next Generation Sequencing approaches. Emerging evidence suggests that domesticated genomes fit well with these expectations, with periods of stable complex evolution characterized by large amounts of change associated with relatively small selective value, punctuated by periods in which changes in one-half of the plant-hominin relationship cause rapid, low-complexity adaptation in the other. A corollary of a single plant-hominin co-evolutionary process is that clues about the initiation of the domestication process may well lie deep within the hominin lineage. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Assembly constraints drive co-evolution among ribosomal constituents.

PubMed

Mallik, Saurav; Akashi, Hiroshi; Kundu, Sudip

2015-06-23

Ribosome biogenesis, a central and essential cellular process, occurs through sequential association and mutual co-folding of protein-RNA constituents in a well-defined assembly pathway. Here, we construct a network of co-evolving nucleotide/amino acid residues within the ribosome and demonstrate that assembly constraints are strong predictors of co-evolutionary patterns. Predictors of co-evolution include a wide spectrum of structural reconstitution events, such as cooperativity phenomenon, protein-induced rRNA reconstitutions, molecular packing of different rRNA domains, protein-rRNA recognition, etc. A correlation between folding rate of small globular proteins and their topological features is known. We have introduced an analogous topological characteristic for co-evolutionary network of ribosome, which allows us to differentiate between rRNA regions subjected to rapid reconstitutions from those hindered by kinetic traps. Furthermore, co-evolutionary patterns provide a biological basis for deleterious mutation sites and further allow prediction of potential antibiotic targeting sites. Understanding assembly pathways of multicomponent macromolecules remains a key challenge in biophysics. Our study provides a 'proof of concept' that directly relates co-evolution to biophysical interactions during multicomponent assembly and suggests predictive power to identify candidates for critical functional interactions as well as for assembly-blocking antibiotic target sites. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Migratory behavior of birds affects their coevolutionary relationship with blood parasites.

PubMed

Jenkins, Tania; Thomas, Gavin H; Hellgren, Olof; Owens, Ian P F

2012-03-01

Host traits, such as migratory behavior, could facilitate the dispersal of disease-causing parasites, potentially leading to the transfer of infections both across geographic areas and between host species. There is, however, little quantitative information on whether variation in such host attributes does indeed affect the evolutionary outcome of host-parasite associations. Here, we employ Leucocytozoon blood parasites of birds, a group of parasites closely related to avian malaria, to study host-parasite coevolution in relation to host behavior using a phylogenetic comparative approach. We reconstruct the molecular phylogenies of both the hosts and parasites and use cophylogenetic tools to assess whether each host-parasite association contributes significantly to the overall congruence between the two phylogenies. We find evidence for a significant fit between host and parasite phylogenies in this system, but show that this is due only to associations between nonmigrant parasites and their hosts. We also show that migrant bird species harbor a greater genetic diversity of parasites compared with nonmigrant species. Taken together, these results suggest that the migratory habits of birds could influence their coevolutionary relationship with their parasites, and that consideration of host traits is important in predicting the outcome of coevolutionary interactions. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Gene pyramiding enhances durable blast disease resistance in rice

PubMed Central

Fukuoka, Shuichi; Saka, Norikuni; Mizukami, Yuko; Koga, Hironori; Yamanouchi, Utako; Yoshioka, Yosuke; Hayashi, Nagao; Ebana, Kaworu; Mizobuchi, Ritsuko; Yano, Masahiro

2015-01-01

Effective control of blast, a devastating fungal disease of rice, would increase and stabilize worldwide food production. Resistance mediated by quantitative trait loci (QTLs), which usually have smaller individual effects than R-genes but confer broad-spectrum or non-race-specific resistance, is a promising alternative to less durable race-specific resistance for crop improvement, yet evidence that validates the impact of QTL combinations (pyramids) on the durability of plant disease resistance has been lacking. Here, we developed near-isogenic experimental lines representing all possible combinations of four QTL alleles from a durably resistant cultivar. These lines enabled us to evaluate the QTLs singly and in combination in a homogeneous genetic background. We present evidence that pyramiding QTL alleles, each controlling a different response to M. oryzae, confers strong, non-race-specific, environmentally stable resistance to blast disease. Our results suggest that this robust defence system provides durable resistance, thus avoiding an evolutionary “arms race” between a crop and its pathogen. PMID:25586962

China’s Nuclear Force Modernization

DTIC Science & Technology

2005-01-01

of mass destruction, see 美伊 战 争 引发核竞 赛？[U.S. War on Iraq Initiated Nuclear Races?], 世界新闻报 [World News Journal], 1 May 2003. 41. Lewis and Hua...Plana, Spain, May 2003. ———.美伊 战 争 引发核竞赛？[U.S. War on Iraq Initiated Nuclear Races?], 世界新闻报 [World News Journal], no. 33, 1 May 2003. Lewis, John, Hua...彬 [Zhou Baogen and Li Bin], 党派政治对冷 战 后美国军控政策的 影响 [Impacts of Party Politics on Ameri- can Arms Control Policy after the Cold War], 世界经济与政治论坛 [Forum

STS-32 crewmembers hold finish line banner as MS Low races on treadmill

NASA Technical Reports Server (NTRS)

1990-01-01

On Columbia's, Orbiter Vehicle (OV) 102's, middeck, STS-32 crewmembers hold marathon finish line banner in front of Mission Specialist (MS) G. David Low as he races on the treadmill. Commander Daniel C. Brandenstein (left) and Pilot James D. Wetherbee (right) each hold an end of the banner reading 'Columbia/STS 32 Around-The-World Marathon' as Low raises his arms above it in runners fashion. The crewmembers are enjoying one of the lighter moments of the 11-day mission. Wetherbee's mother competed in a marathon in Houston while the STS-32 crewmembers had their own in-space version. The treadmill served as an exerciser and also was an important element of onboard biomedical testing.

Connective stability of competitive equilibrium

NASA Technical Reports Server (NTRS)

Siljak, D. D.

1975-01-01

The purpose of this paper is to derive necessary and sufficient conditions for the connective stability of nonlinear matrix systems described by the equation x-dot = A(t, x) x, where the matrix A(t, x) has time-varying nonlinear elements. The results obtained can be used to study the stability of competitive equilibrium in fields as diverse as economics and engineering, model ecosystems, and the arms race.-

Diversity, Inclusion, and Equal Opportunity in the Armed Services: Background and Issues for Congress

DTIC Science & Technology

2016-07-01

from unlawful discrimination based on race, color, national origin, religion, sex (including pregnancy , gender identity, and sexual orientation when...range of online resources for diversity management and equal opportunity programming. DEOMI’s Research Directorate administers a survey called the...Defense Equal Opportunity Climate Survey (DEOCS). This survey is intended to be a tool for commanders to improve their organizational culture. It

Using the IPEDS Peer Analysis System to Compare Tuition Discount Rates

ERIC Educational Resources Information Center

Duggan, Michael; Mathews, Rebecca

2005-01-01

Tuition discounting began in the 1970s as the practice of using university funds to augment federal, state, and private aid and scholarships. When the 1980s saw a decrease in the number of high school seniors, universities began to compete in the arena of price for the first time, sparking what has been called an "arms race" of tuition discounting…

Globe Watch. Teachers' Guide for Globe Watch IV: Mexico, Canada, Finland, Japan, the Arms Race, the Iran-Iraq War.

ERIC Educational Resources Information Center

Turner, Ginny

To enhance the use of the Globe Watch IV public television series, produced jointly by Hampden-Sydney College (Virginia) and the University of North Carolina Center for Public Television, each lesson in this guide provides: (1) a statement of the objective of the program; (2) a synopsis of the issue discussed; (3) background information; (4) brief…

NRH Neuroscience Research Center

DTIC Science & Technology

2008-06-01

embolism , falls, pneumonia, and mental disorders. Patient variables included age, gender, race, payer source, type and side of stroke, stoke location...Effects of an Oral Anabolic Steroid and Conjugated Linoleic Acid • Mean lean body mass (LBM) increased by 4% in arms and 2% in total body while fat ...Subacute Rehabilitation Programs for Medicare Beneficiiaries with Hip Fracture .: Medical Care. 43 (September) No. 9, 892-901. • DeJong, Gebern (2005

Conventional Expeditionary Forces: A 21st Century Triad for Strategic Deterrence

DTIC Science & Technology

2009-05-27

testing and transfers of nuclear materials, the ability to effectively monitor and track all such activities 100% of the time does not exist at present nor...Limited Test Ban Treaty of 1963 sought to stabilize the arms race and reduce environmental damage by banning atmospheric, sea-based, and space-based...nuclear weapons tests , thereby limiting future testing to underground conditions, and was signed 139

USSR Report, World Economy and International Relations, No. 12, December 1986.

DTIC Science & Technology

1987-04-20

world cultural legacy and contributing to peace, disarmament and struggle against the arms race. Uniting the scientists and prominent men of education...representatives emphasize that under conditions where progressive sectors of the economic infrastructure arentatives emphasize that under conditions...state of excitement and emotion disappeared. The "normalization" process was virtually frozen, there was a sharp cutback in intergovernmental contacts

Balance of power in host-virus arms races.

PubMed

Kok, Kin-Hang; Jin, Dong-Yan

2013-07-17

The sensing of viral RNA by the host innate immune system is mediated by RIG-I and its partner PACT. In this issue of Cell Host & Microbe, Luthra et al. (2013) show that the Ebola virus VP35 protein counteracts the action of PACT at the cost of compromising its own function in viral replication. Copyright © 2013 Elsevier Inc. All rights reserved.

An Analysis of the Incidence of Recruiter Irregularities

DTIC Science & Technology

2010-01-01

provided data and answered our questions about the incidence of recruiter irregularities. The people are Ted Disney at the U.S. Army Recruiting...month We first consider a set of enlistee characteristics that are unlikely to be affected by recruiter behavior, including gender , race, religious...attrite from DEP and not actually access, based on demographic characteristics ( gender , education, the Armed Forces Vocational Aptitude Battery

Contrasting Patterns in Mammal–Bacteria Coevolution: Bartonella and Leptospira in Bats and Rodents

PubMed Central

Lei, Bonnie R.; Olival, Kevin J.

2014-01-01

Background Emerging bacterial zoonoses in bats and rodents remain relatively understudied. We conduct the first comparative host–pathogen coevolutionary analyses of bacterial pathogens in these hosts, using Bartonella spp. and Leptospira spp. as a model. Methodology/Principal Findings We used published genetic data for 51 Bartonella genotypes from 24 bat species, 129 Bartonella from 38 rodents, and 26 Leptospira from 20 bats. We generated maximum likelihood and Bayesian phylogenies for hosts and bacteria, and tested for coevoutionary congruence using programs ParaFit, PACO, and Jane. Bartonella spp. and their bat hosts had a significant coevolutionary fit (ParaFitGlobal = 1.9703, P≤0.001; m2 global value = 7.3320, P≤0.0001). Bartonella spp. and rodent hosts also indicated strong overall patterns of cospeciation (ParaFitGlobal = 102.4409, P≤0.001; m2 global value = 86.532, P≤0.0001). In contrast, we were unable to reject independence of speciation events in Leptospira and bats (ParaFitGlobal = 0.0042, P = 0.84; m2 global value = 4.6310, P = 0.5629). Separate analyses of New World and Old World data subsets yielded results congruent with analysis from entire datasets. We also conducted event-based cophylogeny analyses to reconstruct likely evolutionary histories for each group of pathogens and hosts. Leptospira and bats had the greatest number of host switches per parasite (0.731), while Bartonella and rodents had the fewest (0.264). Conclusions/Significance In both bat and rodent hosts, Bartonella exhibits significant coevolution with minimal host switching, while Leptospira in bats lacks evolutionary congruence with its host and has high number of host switches. Reasons underlying these variable coevolutionary patterns in host range are likely due to differences in disease-specific transmission and host ecology. Understanding the coevolutionary patterns and frequency of host-switching events between bacterial pathogens and their hosts will allow better prediction of spillover between mammal reservoirs, and ultimately to humans. PMID:24651646

Joint breast and colorectal cancer screenings in medically underserved women

PubMed Central

Davis, Terry C; Arnold, Connie L; Wolf, Michael S; Bennett, Charles L; Liu, Dachao; Rademaker, Alfred

2016-01-01

Background Breast and colon cancer screening in rural community clinics is underused. Objective To evaluate the effectiveness and cost-effectiveness of alternative interventions designed to promote simultaneous screening for breast and colon cancer in community clinics. Methods A 3-arm, quasi-experimental evaluation was conducted during May 2008-August 2011 in 8 federally qualifed health clinics in predominately rural Louisiana. Baseline screening rates reported by the clinics was <10% for breast cancer (using mammography) and 1%-2% for colon cancer (using the fecal occult blood test [FOBT]). 744 women aged 50 years or older who were eligible for routine mammography and an FOBT were recruited. The combined screening efforts included: enhanced care; health literacy-informed education (education alone), or health literacy-informed education with nurse support (nurse support). Results Postintervention screening rates for completing both tests were 28.1% with enhanced care, 23.7% with education alone, and 38.7% with nurse support. After adjusting for age, race, and literacy, patients who received nurse support were 2.21 times more likely to complete both screenings than were those who received the education alone (95% confidence interval [CI], 1.12-4.38; P = .023). The incremental cost per additional woman completing both screenings was $3,987 for education with nurse support over education alone, and $5,987 over enhanced care. Limitations There were differences between the 3 arms in sociodemographic characteristics, literacy, and previous screening history. Not all variables that were significantly different between arms were adjusted for, therefore adjustments for key variables (age, race, literacy) were made in statistical analyses. Other limitations related generalizability of results. Conclusions Although joint breast and colon cancer screening rates were increased substantially over existing baseline rates in all 3 arms, the completion rate for both tests was modest. Nurse support and telephone follow-up were most effective. However, it is not likely to be cost effective or affordable in clinics with limited resources. PMID:26918252

Increasing Childhood Influenza Vaccination

PubMed Central

Nowalk, Mary Patricia; Lin, Chyongchiou J.; Hannibal, Kristin; Reis, Evelyn C.; Gallik, Gregory; Moehling, Krissy K.; Huang, Hsin-Hui; Allred, Norma J.; Wolfson, David H.; Zimmerman, Richard K.

2014-01-01

Background Since the 2008 inception of universal childhood influenza vaccination, national rates have risen more dramatically among younger children than older children and reported rates across racial/ethnic groups are inconsistent. Interventions may be needed to address age and racial disparities to achieve the recommended childhood influenza vaccination target of 70%. Purpose To evaluate an intervention to increase childhood influenza vaccination across age and racial groups. Methods In 2011–2012, 20 primary care practices treating children were randomly assigned to Intervention and Control arms of a cluster randomized controlled trial to increase childhood influenza vaccination uptake using a toolkit and other strategies including early delivery of donated vaccine, in-service staff meetings, and publicity. Results The average vaccination differences from pre-intervention to the intervention year were significantly larger in the Intervention arm (n=10 practices) than the Control arm (n=10 practices), for children aged 2–8 years (10.2 percentage points (pct pts) Intervention vs 3.6 pct pts Control) and 9–18 years (11.1 pct pts Intervention vs 4.3 pct pts Control, p<0.05), for non-white children (16.7 pct pts Intervention vs 4.6 pct pts Control, p<0.001), and overall (9.9 pct pts Intervention vs 4.2 pct pts Control, p<0.01). In multi-level modeling that accounted for person- and practice-level variables and the interactions among age, race and intervention, the likelihood of vaccination increased with younger age group (6–23 months), white race, commercial insurance, the practice’s pre-intervention vaccination rate, and being in the Intervention arm. Estimates of the interaction terms indicated that the intervention increased the likelihood of vaccination for non-white children in all age groups and white children aged 9–18 years. Conclusions A multi-strategy intervention that includes a practice improvement toolkit can significantly improve influenza vaccination uptake across age and racial groups without targeting specific groups, especially in practices with large percentages of minority children. PMID:25113138

Can individuals who are specialists in death, dying, and bereavement contribute to the prevention and/or mitigation of armed conflicts and cycles of violence?

PubMed

Parkes, Colin Murray; Attig, Thomas; Bendiksen, Robert; Cabrera, Fernando; Corr, Charles; Cox, Gerry; Faust, Susanna; Fulton, Robert; Jupp, Peter; Kallenberg, Kjell; Lamers, Elizabeth; Lamers, William; Long, Scott; McKissock, Diane; McKissock, Mal; Morgan, Mary Ann; Papadatou, Danai; Stevenson, Robert; Stoddard, Sandol; Weiss, Robert; Wrenn, Marcy

2011-01-01

Specialists in death, dying, and bereavement and their consequences for individuals, families, and communities have experience and research findings that are relevant to an understanding of the reactions of individuals faced by deadly violence. At such times, powerful emotions and ingrained patterns of thought and behavior can given rise to disproportionate responses that may feed into cycles of violence. An extended table shows how professionals helping individuals and families faced with violent death share common aims with those aiming to help larger social units faced with armed attacks. It follows that these professionals should work together to improve death education, to prepare people for possible deadly violence and, where possible, to suggest alternatives, to create secure places and relationships in which communication becomes possible, bad news can be broken and understood, feelings examined, differences reconciled, and people can redirect anger into the prevention of escalation rather than its perpetuation. All of these activities hold out hope that cycles of deadly violence can be broken as well as mitigating the consequences when they are not. The undoubted success of the worldwide palliative care movement resulted from the recognition of serious deficiencies in existing services, the provision of an inclusive, holistic, program that extends across medical, social psychological, and spiritual realms of discourse, providing care for patients and their families, irrespective of wealth, race, religion, and political persuasion, by dedicated leaders and teams backed by education and information services and organized across geographical boundaries. It is argued here that the time is ripe for a similar commitment to bring to an end the scandal of armed conflict by a similarly multidisciplinary, multicultural effort to relieve the suffering that both causes and results from armed conflict. This must remain independent of race, religion, political persuasion, and opposing sides and could build upon the leadership, educational models, information services, and international organizations that already exist for the provision of palliative and bereavement care.

Discovery of a Novel Stem Rust Resistance Allele in Durum Wheat that Exhibits Differential Reactions to Ug99 Isolates

PubMed Central

Nirmala, Jayaveeramuthu; Saini, Jyoti; Newcomb, Maria; Olivera, Pablo; Gale, Sam; Klindworth, Daryl; Elias, Elias; Talbert, Luther; Chao, Shiaoman; Faris, Justin; Xu, Steven; Jin, Yue; Rouse, Matthew N.

2017-01-01

Wheat stem rust, caused by Puccinia graminis f. sp. tritici Eriks. & E. Henn, can incur yield losses in susceptible cultivars of durum wheat, Triticum turgidum ssp. durum (Desf.) Husnot. Although several durum cultivars possess the stem rust resistance gene Sr13, additional genes in durum wheat effective against emerging virulent races have not been described. Durum line 8155-B1 confers resistance against the P. graminis f. sp. tritici race TTKST, the variant race of the Ug99 race group with additional virulence to wheat stem rust resistance gene Sr24. However, 8155-B1 does not confer resistance to the first-described race in the Ug99 race group: TTKSK. We mapped a single gene conferring resistance in 8155-B1 against race TTKST, Sr8155B1, to chromosome arm 6AS by utilizing Rusty/8155-B1 and Rusty*2/8155-B1 populations and the 90K Infinium iSelect Custom bead chip supplemented by KASP assays. One marker, KASP_6AS_IWB10558, cosegregated with Sr8155B1 in both populations and correctly predicted Sr8155B1 presence or absence in 11 durum cultivars tested. We confirmed the presence of Sr8155B1 in cultivar Mountrail by mapping in the population Choteau/Mountrail. The marker developed in this study could be used to predict the presence of resistance to race TTKST in uncharacterized durum breeding lines, and also to combine Sr8155B1 with resistance genes effective to Ug99 such as Sr13. The map location of Sr8155B1 cannot rule out the possibility that this gene is an allele at the Sr8 locus. However, race specificity indicates that Sr8155B1 is different from the known alleles Sr8a and Sr8b. PMID:28855282

Arm to leg coordination in elite butterfly swimmers.

PubMed

Chollet, D; Seifert, L; Boulesteix, L; Carter, M

2006-04-01

This study proposed the use of four time gaps to assess arm-to-leg coordination in the butterfly stroke at increasing race paces. Fourteen elite male swimmers swam at four velocities corresponding to the appropriate paces for, respectively, the 400-m, 200-m, 100-m, and 50-m events. The different stroke phases of the arm and leg were identified by video analysis and then used to calculate four time gaps (T1: time gap between entry of the hands in the water and the high break-even point of the first undulation; T2: time gap between the beginning of the hands' backward movement and the low break-even point of the first undulation; T3: time gap between the hands' arrival in a vertical plane to the shoulders and the high break-even point of the second undulation; T4: time gap between the hands' release from the water and the low break-even point of the second undulation), the values of which described the changing relationship of arm to leg movements over an entire stroke cycle. With increases in pace, elite swimmers increased the stroke rate, the relative duration of the arm pull, the recovery and the first downward movement of the legs, and decreased the stroke length, the relative duration of the arm catch phase and the body glide with arms forward (measured by T2), until continuity in the propulsive actions was achieved. Whatever the paces, the T1, T3, and T4 values were close to zero and revealed a high degree of synchronisation at key motor points of the arm and leg actions. This new method to assess butterfly coordination could facilitate learning and coaching by situating the place of the leg undulation in relation with the arm stroke.

On Design Mining: Coevolution and Surrogate Models.

PubMed

Preen, Richard J; Bull, Larry

2017-01-01

Design mining is the use of computational intelligence techniques to iteratively search and model the attribute space of physical objects evaluated directly through rapid prototyping to meet given objectives. It enables the exploitation of novel materials and processes without formal models or complex simulation. In this article, we focus upon the coevolutionary nature of the design process when it is decomposed into concurrent sub-design-threads due to the overall complexity of the task. Using an abstract, tunable model of coevolution, we consider strategies to sample subthread designs for whole-system testing and how best to construct and use surrogate models within the coevolutionary scenario. Drawing on our findings, we then describe the effective design of an array of six heterogeneous vertical-axis wind turbines.

Memorandum of a Conference with President Eisenhower after Sputnik. The Constitution Community: Postwar United States (1945 to Early 1970s).

ERIC Educational Resources Information Center

Traill, David

After World War II ended in 1945, the United States and the Soviet Union (USSR) emerged as the two dominant countries in the post-war world. An arms race began, and this constant pursuit for respect and supremacy was called the Cold War. On October 4, 1957, the USSR launched the world's first intercontinental ballistic missile, with the first…

Scaling of Adult Regional Body Mass and Body Composition as a Whole to Height: Relevance to Body Shape and Body Mass Index

PubMed Central

Schuna, John M.; Peterson, Courtney M.; Thomas, Diana M.; Heo, Moonseong; Hong, Sangmo; Choi, Woong; Heymsfield, Steven B.

2015-01-01

Objectives Adult body mass (MB) empirically scales as height (Ht) squared (MB ∝ Ht2), but does regional body mass and body composition as a whole also scale as Ht2? This question is relevant to a wide range of biological topics, including interpretation of body mass index. Methods Dual-energy x-ray absorptiometry (DXA) was used to quantify regional body mass (head [MH], trunk, arms, legs) and whole-body composition (fat, lean soft tissue [LST], and bone mineral content [BMC]) in non-Hispanic (NH) white, NH black, Mexican American, and Korean adults participating in the National Health and Nutrition Examination Survey (NHANES; n=17,126) and Korean NHANES (n=8,942). Regression models were developed to establish Ht scaling powers for each measured component with adjustments for age and adiposity. Results Exploratory analyses revealed a consistent scaling pattern across men and women of the four race/ethnic groups: regional mass powers, head (~0.8-1) < arms and trunk (~1.8-2.3) < legs (~2.3-2.6); and body composition, LST (~2.0-2.3) < BMC (~2.1-2.4). Small sex and race/ethnic differences in scaling powers were also observed. As body mass scaled uniformly across the eight sex and race/ethnic groups as Ht~2, tall and short subjects differed in body shape (e.g., Mh/Mb ∝ Ht−~1) and composition. Conclusions Adult human body shape and relative composition are a function of body size as defined by stature, a finding that has important implications in multiple areas of biological research. PMID:25381999

Towards social autonomous vehicles: Efficient collision avoidance scheme using Richardson's arms race model.

PubMed

Riaz, Faisal; Niazi, Muaz A

2017-01-01

This paper presents the concept of a social autonomous agent to conceptualize such Autonomous Vehicles (AVs), which interacts with other AVs using social manners similar to human behavior. The presented AVs also have the capability of predicting intentions, i.e. mentalizing and copying the actions of each other, i.e. mirroring. Exploratory Agent Based Modeling (EABM) level of the Cognitive Agent Based Computing (CABC) framework has been utilized to design the proposed social agent. Furthermore, to emulate the functionality of mentalizing and mirroring modules of proposed social agent, a tailored mathematical model of the Richardson's arms race model has also been presented. The performance of the proposed social agent has been validated at two levels-firstly it has been simulated using NetLogo, a standard agent-based modeling tool and also, at a practical level using a prototype AV. The simulation results have confirmed that the proposed social agent-based collision avoidance strategy is 78.52% more efficient than Random walk based collision avoidance strategy in congested flock-like topologies. Whereas practical results have confirmed that the proposed scheme can avoid rear end and lateral collisions with the efficiency of 99.876% as compared with the IEEE 802.11n-based existing state of the art mirroring neuron-based collision avoidance scheme.

On the Materials Science of Nature's Arms Race.

PubMed

Liu, Zengqian; Zhang, Zhefeng; Ritchie, Robert O

2018-06-05

Biological material systems have evolved unique combinations of mechanical properties to fulfill their specific function through a series of ingenious designs. Seeking lessons from Nature by replicating the underlying principles of such biological materials offers new promise for creating unique combinations of properties in man-made systems. One case in point is Nature's means of attack and defense. During the long-term evolutionary "arms race," naturally evolved weapons have achieved exceptional mechanical efficiency with a synergy of effective offense and persistence-two characteristics that often tend to be mutually exclusive in many synthetic systems-which may present a notable source of new materials science knowledge and inspiration. This review categorizes Nature's weapons into ten distinct groups, and discusses the unique structural and mechanical designs of each group by taking representative systems as examples. The approach described is to extract the common principles underlying such designs that could be translated into man-made materials. Further, recent advances in replicating the design principles of natural weapons at differing lengthscales in artificial materials, devices and tools to tackle practical problems are revisited, and the challenges associated with biological and bioinspired materials research in terms of both processing and properties are discussed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A molecular arms race between host innate antiviral response and emerging human coronaviruses.

PubMed

Wong, Lok-Yin Roy; Lui, Pak-Yin; Jin, Dong-Yan

2016-02-01

Coronaviruses have been closely related with mankind for thousands of years. Community-acquired human coronaviruses have long been recognized to cause common cold. However, zoonotic coronaviruses are now becoming more a global concern with the discovery of highly pathogenic severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses causing severe respiratory diseases. Infections by these emerging human coronaviruses are characterized by less robust interferon production. Treatment of patients with recombinant interferon regimen promises beneficial outcomes, suggesting that compromised interferon expression might contribute at least partially to the severity of disease. The mechanisms by which coronaviruses evade host innate antiviral response are under intense investigations. This review focuses on the fierce arms race between host innate antiviral immunity and emerging human coronaviruses. Particularly, the host pathogen recognition receptors and the signal transduction pathways to mount an effective antiviral response against SARS and MERS coronavirus infection are discussed. On the other hand, the counter-measures evolved by SARS and MERS coronaviruses to circumvent host defense are also dissected. With a better understanding of the dynamic interaction between host and coronaviruses, it is hoped that insights on the pathogenesis of newly-identified highly pathogenic human coronaviruses and new strategies in antiviral development can be derived.

Arms race between selfishness and policing: two-trait quantitative genetic model for caste fate conflict in eusocial Hymenoptera.

PubMed

Dobata, Shigeto

2012-12-01

Policing against selfishness is now regarded as the main force maintaining cooperation, by reducing costly conflict in complex social systems. Although policing has been studied extensively in social insect colonies, its coevolution against selfishness has not been fully captured by previous theories. In this study, I developed a two-trait quantitative genetic model of the conflict between selfish immature females (usually larvae) and policing workers in eusocial Hymenoptera over the immatures' propensity to develop into new queens. This model allows for the analysis of coevolution between genomes expressed in immatures and workers that collectively determine the immatures' queen caste fate. The main prediction of the model is that a higher level of polyandry leads to a smaller fraction of queens produced among new females through caste fate policing. The other main prediction of the present model is that, as a result of arms race, caste fate policing by workers coevolves with exaggerated selfishness of the immatures achieving maximum potential to develop into queens. Moreover, the model can incorporate genetic correlation between traits, which has been largely unexplored in social evolution theory. This study highlights the importance of understanding social traits as influenced by the coevolution of conflicting genomes. © 2012 The Author. Evolution© 2012 The Society for the Study of Evolution.

The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity

PubMed Central

Kimura, Kazuki; Chiba, Satoshi

2015-01-01

Several taxa of simultaneously hermaphroditic land snails exhibit a conspicuous mating behaviour, the so-called shooting of love darts. During mating, such land snail species transfer a specific secretion by stabbing a mating partner's body with the love dart. It has been shown that sperm donors benefit from this traumatic secretion transfer, because the secretions manipulate the physiology of a sperm recipient and increase the donors' fertilization success. However, it is unclear whether reception of dart shooting is costly to the recipients. Therefore, the effect of sexual conflict and antagonistic arms races on the evolution of traumatic secretion transfer in land snails is still controversial. To examine this effect, we compared lifetime fecundity and longevity between the individuals that received and did not receive dart shooting from mating partners in Bradybaena pellucida. Our experiments showed that the dart-receiving snails suffered reduction in lifetime fecundity and longevity. These results suggest that the costly mating behaviour, dart shooting, generates conflict between sperm donors and recipients and that sexually antagonistic arms races have contributed to the diversification of the morphological and behavioural traits relevant to dart shooting. Our findings also support theories suggesting a violent escalation of sexual conflict in hermaphroditic animals. PMID:25761713

Towards social autonomous vehicles: Efficient collision avoidance scheme using Richardson’s arms race model

PubMed Central

Niazi, Muaz A.

2017-01-01

This paper presents the concept of a social autonomous agent to conceptualize such Autonomous Vehicles (AVs), which interacts with other AVs using social manners similar to human behavior. The presented AVs also have the capability of predicting intentions, i.e. mentalizing and copying the actions of each other, i.e. mirroring. Exploratory Agent Based Modeling (EABM) level of the Cognitive Agent Based Computing (CABC) framework has been utilized to design the proposed social agent. Furthermore, to emulate the functionality of mentalizing and mirroring modules of proposed social agent, a tailored mathematical model of the Richardson’s arms race model has also been presented. The performance of the proposed social agent has been validated at two levels–firstly it has been simulated using NetLogo, a standard agent-based modeling tool and also, at a practical level using a prototype AV. The simulation results have confirmed that the proposed social agent-based collision avoidance strategy is 78.52% more efficient than Random walk based collision avoidance strategy in congested flock-like topologies. Whereas practical results have confirmed that the proposed scheme can avoid rear end and lateral collisions with the efficiency of 99.876% as compared with the IEEE 802.11n-based existing state of the art mirroring neuron-based collision avoidance scheme. PMID:29040294

Promote health, not nuclear weapons: ethical duty of medical professionals.

PubMed

Mitra, Arun

2018-03-07

Despite ongoing tensions in various parts of the world, the year 2017 ended on a positive note. The Treaty Prohibiting Nuclear Weapons (TPNW) was passed by the UN General Assembly on July 7, 2017, which will always be a red-letter day in history. It has raised many hopes for a future world without nuclear weapons and staved off the impending humanitarian catastrophe. Good health is a basic need of every individual. Therefore, each person yearns for a life free of violence and free of man-made catastrophes like the ones at Hiroshima and Nagasaki in 1945, which killed over two hundred thousand people and resulted in genetic mutations affecting generations thereafter. Unfortunately, instead of working for nuclear disarmament, the world moved towards an unending nuclear arms race, costing billions which could have been used for healing millions of people living in despair and sickness. This is why on December 10, 2017, Oslo, the capital of Norway, was filled with excitement when the Nobel Peace Prize for this year was bestowed upon the International Campaign to Abolish Nuclear Weapons (ICAN). Large numbers of medical professionals from around the globe had gathered there to affirm their commitment to a healthy future through diversion of wasteful expenditure from the nuclear arms race towards universal health.

The effect of intensive glucose lowering therapy among major racial/ethnic groups in the Veterans Affairs Diabetes Trial

PubMed Central

Saremi, Aramesh; Schwenke, Dawn C.; Bahn, Gideon; Ge, Ling; Emanuele, Nicholas; Reaven, Peter D.

2014-01-01

Objective To examine the effect of intensive glycemic control on cardiovascular disease events (CVD) among the major race/ethnic groups in a post-hoc analysis of the VADT. Materials and Methods Participants included 1111 non-Hispanic Whites, 307 Hispanics and 306 non-Hispanic Blacks randomized to intensive or standard glucose treatment in VADT. Multivariable Cox proportional hazards models were constructed to assess the effect of intensive glucose treatment on CVD events among race/ethnic groups. Results Mean age was 60.4 years and median follow-up was 5.6 years. By design, modifiable risk factors were managed equally well in both treatment arms and only differed modestly between race/ethnic groups. HbA1c decreased significantly from baseline with intensive glucose treatment in each race/ethnic group, with a trend for a greater response in Hispanics (P=0.02 for overall comparison between groups). Intensive glucose treatment was associated with reduced risk of CVD events for Hispanics but not for others (hazard ratios ranged from 0.54 to 0.75 for Hispanics whereas they were consistently close to 1 for others). Sensitivity analyses with different definitions of race/ethnicity or limited to individuals free of previous known CVD yielded similar results. Conclusions The results of these analyses support the hypothesis that race/ethnicity is worthy of consideration when tailoring intensive treatment for individuals with long-standing type 2 diabetes. However, additional studies are needed to confirm the findings of this post-hoc analysis. PMID:25456099

Coevolutionary dynamics of aspiration and strategy in spatial repeated public goods games

NASA Astrophysics Data System (ADS)

Wu, Te; Fu, Feng; Wang, Long

2018-06-01

The evolutionary dynamics remain largely unknown for spatial populations where individuals are more likely to interact repeatedly. Under this settings, individuals can make their decisions to cooperate or not based on the decisions previously adopted by others in their neighborhoods. Using repeated public goods game, we construct a spatial model and use a statistical physics approach to study the coevolutionary dynamics of aspiration and strategy. Individuals each have an aspiration towards the groups they are involved. According to the outcome of each group, individuals have assessment of whether their aspirations are satisfied. If satisfied, they cooperate next round. Otherwise, they switch to defecting. Results show threshold phenomenon for harsh collective dilemma: cooperators sticking to high levels of aspiration can prevail over defectors, while cooperators with other levels are invariably wiped out. When the collective dilemma is relaxed, cooperation is greatly facilitated by inducing a high level of diversity of aspiration. Snapshots further show the spatial patterns of how this coevolutionary process leads to the emergence of an optimal solution associated with aspiration level, whose corresponding strategy are most prevalent. This optimal solution lies in one and the highest aspiration level allowed, and depends on the intensity of the social dilemma. By removing the memory effect, our results also confirm that repeated interactions can promote cooperation, but to a limited degree.

Natural Hazard Management from a Coevolutionary Perspective: Exposure and Policy Response in the European Alps.

PubMed

Fuchs, Sven; Röthlisberger, Veronika; Thaler, Thomas; Zischg, Andreas; Keiler, Margreth

2017-03-04

A coevolutionary perspective is adopted to understand the dynamics of exposure to mountain hazards in the European Alps. A spatially explicit, object-based temporal assessment of elements at risk to mountain hazards (river floods, torrential floods, and debris flows) in Austria and Switzerland is presented for the period from 1919 to 2012. The assessment is based on two different data sets: (1) hazard information adhering to legally binding land use planning restrictions and (2) information on building types combined from different national-level spatial data. We discuss these transdisciplinary dynamics and focus on economic, social, and institutional interdependencies and interactions between human and physical systems. Exposure changes in response to multiple drivers, including population growth and land use conflicts. The results show that whereas some regional assets are associated with a strong increase in exposure to hazards, others are characterized by a below-average level of exposure. The spatiotemporal results indicate relatively stable hot spots in the European Alps. These results coincide with the topography of the countries and with the respective range of economic activities and political settings. Furthermore, the differences between management approaches as a result of multiple institutional settings are discussed. A coevolutionary framework widens the explanatory power of multiple drivers to changes in exposure and risk and supports a shift from structural, security-based policies toward an integrated, risk-based natural hazard management system.

Natural Hazard Management from a Coevolutionary Perspective: Exposure and Policy Response in the European Alps

PubMed Central

Fuchs, Sven; Röthlisberger, Veronika; Thaler, Thomas; Zischg, Andreas; Keiler, Margreth

2017-01-01

A coevolutionary perspective is adopted to understand the dynamics of exposure to mountain hazards in the European Alps. A spatially explicit, object-based temporal assessment of elements at risk to mountain hazards (river floods, torrential floods, and debris flows) in Austria and Switzerland is presented for the period from 1919 to 2012. The assessment is based on two different data sets: (1) hazard information adhering to legally binding land use planning restrictions and (2) information on building types combined from different national-level spatial data. We discuss these transdisciplinary dynamics and focus on economic, social, and institutional interdependencies and interactions between human and physical systems. Exposure changes in response to multiple drivers, including population growth and land use conflicts. The results show that whereas some regional assets are associated with a strong increase in exposure to hazards, others are characterized by a below-average level of exposure. The spatiotemporal results indicate relatively stable hot spots in the European Alps. These results coincide with the topography of the countries and with the respective range of economic activities and political settings. Furthermore, the differences between management approaches as a result of multiple institutional settings are discussed. A coevolutionary framework widens the explanatory power of multiple drivers to changes in exposure and risk and supports a shift from structural, security-based policies toward an integrated, risk-based natural hazard management system. PMID:28267154

Flood hazard management from a coevolutionary perspective: exposure and policy response in the European Alps

NASA Astrophysics Data System (ADS)

Fuchs, Sven; Röthlisberger, Veronika; Thaler, Thomas; Zischg, Andreas; Keiler, Margreth

2017-04-01

A coevolutionary perspective is adopted to understand the dynamics of exposure to hydrological hazards in the European Alps. A spatially explicit, object-based temporal assessment of elements at risk to flood hazards (river floods, torrential floods and debris flows) in Austria and Switzerland is presented for the 1919-2012 period. The assessment is based on two different datasets, (a) hazard information adhering to legally binding land use planning restrictions and (b) information on building types combined from different national level spatial data. We discuss these transdisciplinary dynamics and focus on economic, social and institutional interdependencies and interactions between human and physical systems. Exposure changes in the response to multiple drivers, including population growth and land use conflicts. The results show that while some regional assets are associated with a strong increase in exposure to hazards, others are characterized by a below-average level of exposure. The spatiotemporal results indicate relatively stable hot spots in the European Alps. These results coincide with the topography of the countries and with the respective range of economic activities and political settings. Furthermore, the differences between management approaches as a result of multiple institutional settings are discussed. A coevolutionary framework widens the explanatory power of multiple drivers to changes in exposure and risk, and supports a shift from structural, security-based policies towards an integrated, risk-based natural hazard management system.

The Fit Study: Design and rationale for a cluster randomized trial of school-based BMI screening and reporting.

PubMed

Madsen, Kristine A; Linchey, Jennifer; Ritchie, Lorrene; Thompson, Hannah R

2017-07-01

In the U.S., 25 states conduct body mass index (BMI) screening in schools, just under half of which report results to parents. While some experts recommend the practice, evidence demonstrating its efficacy to reduce obesity is lacking, and concerns about weight-related stigma have been raised. The Fit Study is a 3-arm cluster-randomized trial assessing the effectiveness of school-based BMI screening and reporting in reducing pediatric obesity and identifying unintended consequences. Seventy-nine elementary and middle schools across California were randomized to 1 of 3 Arms: 1) BMI screening and reporting; 2) BMI screening only; or 3) no BMI screening or reporting. In Arm 1 schools, students were further randomized to receive reports with BMI results alone or both BMI and fitness test results. Over 3 consecutive years, staff in schools in Arms 1 and 2 will measure students' BMI (grades 3-8) and additional aspects of fitness (grades 5-8), and students in grades 4-8 in all Arms will complete surveys to assess weight-based stigmatization. Change in BMI z-score will be compared between Arm 1 and Arm 2 to determine the impact of BMI reporting on weight status, with sub-analyses stratified by report type (BMI results alone versus BMI plus fitness results) and by race/ethnicity. The potential for BMI reports to lead to weight-based stigma will be assessed by comparing student survey results among the 3 study Arms. This study will provide evidence on both the benefit and potential unintended harms of school-based BMI screening and reporting. Copyright © 2017. Published by Elsevier Inc.

Chromosomal phylogeny of Robertsonian races of the house mouse on the island of Madeira: testing between alternative mutational processes.

PubMed

Britton-Davidian, Janice; Catalan, Josette; da Graça Ramalhinho, Maria; Auffray, Jean-Christophe; Claudia Nunes, Ana; Gazave, Elodie; Searle, Jeremy B; da Luz Mathias, Maria

2005-12-01

The ancestral karyotype of the house mouse (Mus musculus) consists of 40 acrocentric chromosomes, but numerous races exist within the domesticus subspecies characterized by different metacentric chromosomes formed by the joining at the centromere of two acrocentrics. An exemplary case is present on the island of Madeira where six highly divergent chromosomal races have accumulated different combinations of 20 metacentrics in 500-1000 years. Chromosomal cladistic phylogenies were performed to test the relative performance of Robertsonian (Rb) fusions, Rb fissions and whole-arm reciprocal translocations (WARTs) in resolving relationships between the chromosomal races. The different trees yielded roughly similar topologies, but varied in the number of steps and branch support. The analyses using Rb fusions/fissions as characters resulted in poorly supported trees requiring six to eight homoplasious events. Allowance for WARTs considerably increased nodal support and yielded the most parsimonious trees since homoplasy was reduced to a single event. The WART-based trees required five to nine WARTs and 12 to 16 Rb fusions. These analyses provide support for the role of WARTs in generating the extensive chromosomal diversification observed in house mice. The repeated occurrence of Rb fusions and WARTs highlights the contribution of centromere-related rearrangements to accelerated rates of chromosomal change in the house mouse.

Comparing a Coevolutionary Genetic Algorithm for Multiobjective Optimization

NASA Technical Reports Server (NTRS)

Lohn, Jason D.; Kraus, William F.; Haith, Gary L.; Clancy, Daniel (Technical Monitor)

2002-01-01

We present results from a study comparing a recently developed coevolutionary genetic algorithm (CGA) against a set of evolutionary algorithms using a suite of multiobjective optimization benchmarks. The CGA embodies competitive coevolution and employs a simple, straightforward target population representation and fitness calculation based on developmental theory of learning. Because of these properties, setting up the additional population is trivial making implementation no more difficult than using a standard GA. Empirical results using a suite of two-objective test functions indicate that this CGA performs well at finding solutions on convex, nonconvex, discrete, and deceptive Pareto-optimal fronts, while giving respectable results on a nonuniform optimization. On a multimodal Pareto front, the CGA finds a solution that dominates solutions produced by eight other algorithms, yet the CGA has poor coverage across the Pareto front.

Racial disparity in oncologic and quality-of-life outcomes in patients with locally advanced head and neck squamous cell carcinomas enrolled in a randomized phase 2 trial.

PubMed

Guerriero, Margaret K; Redman, Mary W; Baker, Kelsey K; Martins, Renato G; Eaton, Keith; Chow, Laura Q; Santana-Davila, Rafael; Baik, Christina; Goulart, Bernardo H; Lee, Sylvia; Rodriguez, Cristina P

2018-04-18

To better understand patient-reported quality of life (PRQOL) for patients with head and neck cancer, PRQOL scores were collected in a clinical trial. Patients were randomized to arm A (70 Gy of radiation with cisplatin) or arm B (70 Gy of radiation with cisplatin plus erlotinib at 150 mg daily). PRQOL scores were measured on days -7 (arm B only), 0, 30, and 180 with the University of Washington Quality of Life Questionnaire. Associations with clinical factors and outcomes were explored with linear mixed, logistic, and Cox regression models. One hundred eighty-nine patients (97 in arm A and 92 in arm B) consented to PRQOL collection. Patients were balanced apart from more females in arm A (20 [21%] vs 8 [9%]; P = .02). There were 17 black patients (18%) in arm A and 12 (13%) in arm B (P = .39). There was no change in the mean scores in arm B from day -7 to day 0 (P = .36). Scores were lower in both arms at day 30 (P for both < .0001), with no difference by arm (P = .10). Scores on day 180 remained lower for arm A (-6.79; 95% confidence interval [CI], -12.6 to -1.0; P = .02). In arm B, this difference was not significant, and this suggested that the scores had returned to the baseline by day 180 (P = .73). After adjustments for potential confounders, black race was an independent predictor for inferior scores (-11.4; 95% CI, -16.84 to -5.94; P < .0001), complete response rates (odds ratio, 0.34; 95% CI, 0.12-0.91; P = .03), and overall survival (hazard ratio, 3.71; 95% CI, 1.63-8.47; P < .01). PRQOL scores predictably worsened during and improved after chemoradiation. Black patients had inferior PRQOL and overall survival. Cancer 2018. © 2018 American Cancer Society. © 2018 American Cancer Society.

The Next Arms Race

DTIC Science & Technology

2012-07-01

to curb the proliferation of the means of deliv- ery for weapons of mass destruction. Looking ahead, it will be of critical importance to seek...pects, Berkeley, CA: University of California Press, 2002, p. 91. 27. As to how many nuclear weapons China has, no one knows. A sharp critic of an...in Siberia and the Far East, where Chinese military modernization has moved the People’s Liberation Army (PLA) from a mass industri- al army built to

Toxoplasma's arms race with the host interferon response: a ménage à trois of ROPs.

PubMed

Zhao, Yanlin; Yap, George S

2014-05-14

The Toxoplasma gondii virulence factors ROP5 and ROP18 both target immunity-related GTPases (IRGs) to evade immunity. In this issue of Cell Host & Microbe, Etheridge et al. (2014) identify a third virulence factor, ROP17, which forms a complex and synergizes with ROP5/ROP18 to fully disable the IRG system of antiparasite defense. Copyright © 2014 Elsevier Inc. All rights reserved.

Atomic papers: a citizen's guide to selected books and articles on the bomb, the arms race, nuclear power, the peace movement, and related issues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, G.

This bibliography, updated from an earlier 1947 printing, is divided into 18 separate areas. It will allow the reader to identify books and recent journal and magazine articles on the panoply of nuclear issues. It assumed that better information enables more-effective involvement in the effort to secure real peace, and not the dubious peace achieved through nuclear terror.

Defense Spending in Latin America: Arms Race or Commodity Boom

DTIC Science & Technology

2008-12-01

over their territorial and maritime border, while many Peruvians and Bolivians still hold a grudge over the immense amount of Bolivian territory lost...and difficult to understand. Some were so complicated it was difficult distinguishing them from the RANDOM strategy. Unlike in football , where one...since the War of the Pacific when Chile annexed a large portion of Peruvian land and shut off access to the sea to Bolivia. Although Chile’s national

Shoulder and hip joints for hard space suits and the like

NASA Technical Reports Server (NTRS)

Vykukal, H. C.

1986-01-01

For use in hard space suits and the like, a joint between the torso covering and the upper arm covering (i.e., shoulder) or between the torso covering and upper leg covering (i.e., hip) is disclosed. Each joint has an outer covering and a inner covering. The outer covering has plural perferably truncated toroidal sections decreasing in size proceeding outwardly. In one embodiment at each joint there are two bearings, the first larger than the second. The outer race of the larger bearing is attached to the outer edge of the smaller end of each section and the inner race of the larger bearing is attached to the end wall. The inner race of the smaller bearing is attached to the end wall. The outer race of the smaller bearing is attached to the larger end of the next section. Each bearing hask appropriate seals. Between each section is a rubber ring for the comfort of the wearer. Such rubber rings have radial flanges attached to the inner races of two adjacent bearings. Matching semicircular grooves are formed in the abutting overlapping surfaces. Bellows-like inner walls are also provided for each section fixed at one end to an inner cylindrical flange and, at the opposite end, to an end wall. Each outer section may rotate 360 deg relative to the next outer section, whereas the bellows sections do not rotate, but rather expand or contract locally as the rigid sections rotate relative to each other.

The militarization of space: U. S. policy, 1945-1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stares, P.B.

1985-01-01

This is an account of the U.S. military space program under successive administrations. Despite Sputnik and the advent of reconnaissance satellites, the development of antisatellite space weapons was resisted from the time of the Eisenhower Administration until the late 1970s. Indeed, Eisenhower wanted to keep U.S. activities in space ''peaceful'' so as to avoid a threat to reconnaissance satellites. When Soviet satellite interceptor tests became a matter of concern, the Carter Administration pursued a two-track policy of seeking to develop the technology and to ban its deployment through negotiations with the Soviet Union; thereafter, the Reagan Administration dropped arms controlmore » efforts and insisted upon testing. The author concludes that an arms race in space is now inevitable-and that a solid opportunity has been lost.« less

Co-evolutionary dynamics of the human-environment system in the Heihe River basin in the past 2000years.

PubMed

Lu, Zhixiang; Wei, Yongping; Feng, Qi; Xie, Jiali; Xiao, Honglang; Cheng, Guodong

2018-09-01

There is limited quantitative understanding of interactions between human and environmental systems over the millennial scale. We aim to reveal the co-evolutionary dynamics of the human-environment system in a river basin by simulating the water use and net primary production (NPP) allocation for human and environmental systems over the last 2000years in Heihe River basin (HRB) in northwest China. We partition the catchment total evapotranspiration (ET) into ET for human and environmental systems with a social-hydrological framework and estimate the NPP for human and environmental systems using the Box-Lieth model, then classify the co-evolutionary processes of the human-environment system into distinct phases using the rate of changes of NPP over time, and discover the trade-offs or synergies relationships between them based on the elasticity of change of the NPP for humans to the change of NPP for environment. The co-evolutionary dynamics of human-environment system in the HRB can be divided into four periods, including: Phase I (Han Dynasty-Yuan Dynasty): predevelopment characterized by nearly no trade-offs between human and environment; Phase II (Yuan Dynasty-RC): slow agricultural development: characterized by a small human win due to small trade-offs between human and environment; Phase III (RC-2000): rapid agricultural development: characterized by a large human win due to large trade-offs between human and environment, and Phase IV (2000-2010): a rebalance characterized by large human wins with a small-environment win due to synergies, although these occurred very occasionally. This study provides a quantitative approach to describe the co-evolution of the human-environment system from the perspective of trade-offs and synergies in the millennial scale for the first time. The relationships between humans and environment changed from trade-off to synergy with the implementation of the water reallocation scheme in 2000. These findings improve the understanding of how humans influence environmental systems and responses to environmental stresses. Copyright © 2018 Elsevier B.V. All rights reserved.

Coevolutionary diversification creates nested-modular structure in phage–bacteria interaction networks

PubMed Central

Beckett, Stephen J.; Williams, Hywel T. P.

2013-01-01

Phage and their bacterial hosts are the most diverse and abundant biological entities in the oceans, where their interactions have a major impact on marine ecology and ecosystem function. The structure of interaction networks for natural phage–bacteria communities offers insight into their coevolutionary origin. At small phylogenetic scales, observed communities typically show a nested structure, in which both hosts and phages can be ranked by their range of resistance and infectivity, respectively. A qualitatively different multi-scale structure is seen at larger phylogenetic scales; a natural assemblage sampled from the Atlantic Ocean displays large-scale modularity and local nestedness within each module. Here, we show that such ‘nested-modular’ interaction networks can be produced by a simple model of host–phage coevolution in which infection depends on genetic matching. Negative frequency-dependent selection causes diversification of hosts (to escape phages) and phages (to track their evolving hosts). This creates a diverse community of bacteria and phage, maintained by kill-the-winner ecological dynamics. When the resulting communities are visualized as bipartite networks of who infects whom, they show the nested-modular structure characteristic of the Atlantic sample. The statistical significance and strength of this observation varies depending on whether the interaction networks take into account the density of the interacting strains, with implications for interpretation of interaction networks constructed by different methods. Our results suggest that the apparently complex community structures associated with marine bacteria and phage may arise from relatively simple coevolutionary origins. PMID:24516719

Coevolutionary dynamics in large, but finite populations

NASA Astrophysics Data System (ADS)

Traulsen, Arne; Claussen, Jens Christian; Hauert, Christoph

2006-07-01

Coevolving and competing species or game-theoretic strategies exhibit rich and complex dynamics for which a general theoretical framework based on finite populations is still lacking. Recently, an explicit mean-field description in the form of a Fokker-Planck equation was derived for frequency-dependent selection with two strategies in finite populations based on microscopic processes [A. Traulsen, J. C. Claussen, and C. Hauert, Phys. Rev. Lett. 95, 238701 (2005)]. Here we generalize this approach in a twofold way: First, we extend the framework to an arbitrary number of strategies and second, we allow for mutations in the evolutionary process. The deterministic limit of infinite population size of the frequency-dependent Moran process yields the adjusted replicator-mutator equation, which describes the combined effect of selection and mutation. For finite populations, we provide an extension taking random drift into account. In the limit of neutral selection, i.e., whenever the process is determined by random drift and mutations, the stationary strategy distribution is derived. This distribution forms the background for the coevolutionary process. In particular, a critical mutation rate uc is obtained separating two scenarios: above uc the population predominantly consists of a mixture of strategies whereas below uc the population tends to be in homogeneous states. For one of the fundamental problems in evolutionary biology, the evolution of cooperation under Darwinian selection, we demonstrate that the analytical framework provides excellent approximations to individual based simulations even for rather small population sizes. This approach complements simulation results and provides a deeper, systematic understanding of coevolutionary dynamics.

Aerospace Power Journal. Volume 16, Number 1, Spring 2002

DTIC Science & Technology

2002-01-01

war fight­ ers (or “ pulled ” by requirements). Rather, they focused on “technology push”—systems that should be built merely because they could be...impact on our national security strategy. On 13 December 2001, President George W. Bush announced that the United States would pull out of the...to increase the arms race and pull out of previous treaties, as well as “shield of dreams” accusations), eco­ nomic reality (estimates run from

Fire for Effect: Calling for a More Potent Energy System

DTIC Science & Technology

2008-05-22

threatened non-renewal of treaties on nuclear weapons. 63 This includes Russian sales of the state of the art S-300 air defense system to Iran and...includes the ability to easily find a filling station for your type of vehicle. Several types of alternative fueled vehicle sales suffered because...New Nuclear Arms Race,” Stanford University Freeman Spogli Institute of International Studies podcast MP3 file. 1:25:16, 8 August 2007 via iTunes

Africa: A Strategic Factor in the Strategic Equation of the World.

DTIC Science & Technology

1984-05-02

is no clear-cut ideology in any part of the continent except for South Africa. That country has settled for minority democracy based on racially rooted ...assume that arms race in Africa, though unfashionable, has taken root . Egypt’s nuclear program has been mentioned and the disquiet expressions coming...Phosphates COMOROS 1. Flowers Perfume 2. Vanilla 3. Copra, Cloves, Cinnamon 4. Rice, Cassava 5. Bananas MAURITIUS I. Maize 2. Potatoes 3. Cattle 4

CTC Sentinel. Volume 9, Issue 5, May 2016

DTIC Science & Technology

2016-05-01

after a bomb hidden in a laptop was detonated onboard a Somali passenger jet in February, focuses on the technological arms race between terrorist... bomb makers and those working to prevent bombs from getting onto planes. Robert Liscouski and William McGann, two leading specialists in aviation...SENTINEL 1 The mid-air bombing of a Somali passenger jet in Feb- ruary was a wake-up call for security agencies and those working in the field of

New Weapons and the Arms Race

NASA Astrophysics Data System (ADS)

Tsipis, Kosta

1983-10-01

In speaking about technologies that could further animate the weapons competition between the United States and the U.S.S.R., it would be useful to distinguish between technologies that have already been incorporated into specific weapons systems, and new technologies that are of a generic nature, can be used in a variety of applications, adn can best be described by the tasks that they can perform rather than any specific weapons application. Let me begin with the latter class.

[Objective non-contact method of study of the color of the human skin integument by use of a photoelectric colorimeter].

PubMed

Gruzdeva, N I; Zherebtsov, L D; Vasilevskiĭ, V K; Vremzen, S A

1975-04-01

The authors describe a method of determination of the colour of the skin in man based on the use of contactless photoelectric colorimeter made especially for this purpose. The mean normal values of the indices of the skin colour of the anterior and the posterior surface of the arm in 45 men and 35 women of the Europeoid race under normal conditions are presented.

Investigation of a Passive, Temporal, Neutron Monitoring System that Functions within the Confines of Start I

DTIC Science & Technology

2003-03-01

was appreciated and their expertise was invaluable. I would also like to thank laboratory technician, Mr. Eric Taylor, whose assistance, skill...Sagdeev, “Detecting Nuclear Warheads,” in Reversing the Arms Race: How to Achieve and Verify Deep Reductions in the Nuclear Arsenals. Ed. F. von ... Hippel and R.Z. Sagdeev. New York: Gordon and Breach Science Publishers, 1990 7) Brigman, Charles J. Introduction To The Physics of Nuclear Weapon

RNA-Interference Pathways Display High Rates of Adaptive Protein Evolution in Multiple Invertebrates

PubMed Central

Palmer, William H.; Hadfield, Jarrod D.; Obbard, Darren J.

2018-01-01

Conflict between organisms can lead to a reciprocal adaptation that manifests as an increased evolutionary rate in genes mediating the conflict. This adaptive signature has been observed in RNA-interference (RNAi) pathway genes involved in the suppression of viruses and transposable elements in Drosophila melanogaster, suggesting that a subset of Drosophila RNAi genes may be locked in an arms race with these parasites. However, it is not known whether rapid evolution of RNAi genes is a general phenomenon across invertebrates, or which RNAi genes generally evolve adaptively. Here we use population genomic data from eight invertebrate species to infer rates of adaptive sequence evolution, and to test for past and ongoing selective sweeps in RNAi genes. We assess rates of adaptive protein evolution across species using a formal meta-analytic framework to combine data across species and by implementing a multispecies generalized linear mixed model of mutation counts. Across species, we find that RNAi genes display a greater rate of adaptive protein substitution than other genes, and that this is primarily mediated by positive selection acting on the genes most likely to defend against viruses and transposable elements. In contrast, evidence for recent selective sweeps is broadly spread across functional classes of RNAi genes and differs substantially among species. Finally, we identify genes that exhibit elevated adaptive evolution across the analyzed insect species, perhaps due to concurrent parasite-mediated arms races. PMID:29437826

Functional anatomy and muscle moment arms of the thoracic limb of an elite sprinting athlete: the racing greyhound (Canis familiaris)

PubMed Central

Williams, S B; Wilson, A M; Daynes, J; Peckham, K; Payne, R C

2008-01-01

We provide quantitative muscle–tendon architecture and geometry data for the racing greyhound thoracic limb. Muscle mass, belly length, fascicle lengths, pennation angles and moment arms were measured, as were tendon masses and lengths. Maximum isometric force and maximum power were estimated for muscles, and maximum stress and strain were estimated for tendons. Results are compared with other fast quadrupedal runners, and to previously published data in mixed-breed dogs. The implications of the functional adaptations of the greyhound thoracic limb for sprinting performance are discussed. The thoracic limb was found to benefit from a similar proportion of locomotor muscle mass to the pelvic limb, suggesting that it may be used to some extent in propulsion, or alternatively that stabilisation is very important in this animal. Extrinsic muscles, especially latissimus dorsi and pectoralis profundus, were predicted to be powerful and important for generating net positive work during accelerations. Proximal biarticular muscles show specialisation toward preventing collapse of the shoulder and elbow joints to enable strut-like limb function, or some form of dynamic control. Distal muscles did not appear specialised for elastic energy storage, a functional difference to pelvic limb muscles, and the equivalents in horse thoracic limbs. The greyhound thoracic limb appears to possess substantial differences from both that of more ‘sub-maximal specialist’ quadrupeds, and from the greyhound pelvic limb. PMID:19034998

Functional anatomy and muscle moment arms of the thoracic limb of an elite sprinting athlete: the racing greyhound (Canis familiaris).

PubMed

Williams, S B; Wilson, A M; Daynes, J; Peckham, K; Payne, R C

2008-10-01

We provide quantitative muscle-tendon architecture and geometry data for the racing greyhound thoracic limb. Muscle mass, belly length, fascicle lengths, pennation angles and moment arms were measured, as were tendon masses and lengths. Maximum isometric force and maximum power were estimated for muscles, and maximum stress and strain were estimated for tendons. Results are compared with other fast quadrupedal runners, and to previously published data in mixed-breed dogs. The implications of the functional adaptations of the greyhound thoracic limb for sprinting performance are discussed. The thoracic limb was found to benefit from a similar proportion of locomotor muscle mass to the pelvic limb, suggesting that it may be used to some extent in propulsion, or alternatively that stabilisation is very important in this animal. Extrinsic muscles, especially latissimus dorsi and pectoralis profundus, were predicted to be powerful and important for generating net positive work during accelerations. Proximal biarticular muscles show specialisation toward preventing collapse of the shoulder and elbow joints to enable strut-like limb function, or some form of dynamic control. Distal muscles did not appear specialised for elastic energy storage, a functional difference to pelvic limb muscles, and the equivalents in horse thoracic limbs. The greyhound thoracic limb appears to possess substantial differences from both that of more 'sub-maximal specialist' quadrupeds, and from the greyhound pelvic limb.

Corrective response times in a coordinated eye-head-arm countermanding task.

PubMed

Tao, Gordon; Khan, Aarlenne Z; Blohm, Gunnar

2018-06-01

Inhibition of motor responses has been described as a race between two competing decision processes of motor initiation and inhibition, which manifest as the reaction time (RT) and the stop signal reaction time (SSRT); in the case where motor initiation wins out over inhibition, an erroneous movement occurs that usually needs to be corrected, leading to corrective response times (CRTs). Here we used a combined eye-head-arm movement countermanding task to investigate the mechanisms governing multiple effector coordination and the timing of corrective responses. We found a high degree of correlation between effector response times for RT, SSRT, and CRT, suggesting that decision processes are strongly dependent across effectors. To gain further insight into the mechanisms underlying CRTs, we tested multiple models to describe the distribution of RTs, SSRTs, and CRTs. The best-ranked model (according to 3 information criteria) extends the LATER race model governing RTs and SSRTs, whereby a second motor initiation process triggers the corrective response (CRT) only after the inhibition process completes in an expedited fashion. Our model suggests that the neural processing underpinning a failed decision has a residual effect on subsequent actions. NEW & NOTEWORTHY Failure to inhibit erroneous movements typically results in corrective movements. For coordinated eye-head-hand movements we show that corrective movements are only initiated after the erroneous movement cancellation signal has reached a decision threshold in an accelerated fashion.

The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity.

PubMed

Kimura, Kazuki; Chiba, Satoshi

2015-04-07

Several taxa of simultaneously hermaphroditic land snails exhibit a conspicuous mating behaviour, the so-called shooting of love darts. During mating, such land snail species transfer a specific secretion by stabbing a mating partner's body with the love dart. It has been shown that sperm donors benefit from this traumatic secretion transfer, because the secretions manipulate the physiology of a sperm recipient and increase the donors' fertilization success. However, it is unclear whether reception of dart shooting is costly to the recipients. Therefore, the effect of sexual conflict and antagonistic arms races on the evolution of traumatic secretion transfer in land snails is still controversial. To examine this effect, we compared lifetime fecundity and longevity between the individuals that received and did not receive dart shooting from mating partners in Bradybaena pellucida. Our experiments showed that the dart-receiving snails suffered reduction in lifetime fecundity and longevity. These results suggest that the costly mating behaviour, dart shooting, generates conflict between sperm donors and recipients and that sexually antagonistic arms races have contributed to the diversification of the morphological and behavioural traits relevant to dart shooting. Our findings also support theories suggesting a violent escalation of sexual conflict in hermaphroditic animals. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Muscle Damage and Its Relationship with Muscle Fatigue During a Half-Iron Triathlon

PubMed Central

Coso, Juan Del; González-Millán, Cristina; Salinero, Juan José; Abián-Vicén, Javier; Soriano, Lidón; Garde, Sergio; Pérez-González, Benito

2012-01-01

Background To investigate the cause/s of muscle fatigue experienced during a half-iron distance triathlon. Methodology/Principal Findings We recruited 25 trained triathletes (36±7 yr; 75.1±9.8 kg) for the study. Before and just after the race, jump height and leg muscle power output were measured during a countermovement jump on a force platform to determine leg muscle fatigue. Body weight, handgrip maximal force and blood and urine samples were also obtained before and after the race. Blood myoglobin and creatine kinase concentrations were determined as markers of muscle damage. Results Jump height (from 30.3±5.0 to 23.4±6.4 cm; P<0.05) and leg power output (from 25.6±2.9 to 20.7±4.6 W · kg−1; P<0.05) were significantly reduced after the race. However, handgrip maximal force was unaffected by the race (430±59 to 430±62 N). Mean dehydration after the race was 2.3±1.2% with high inter-individual variability in the responses. Blood myoglobin and creatine kinase concentration increased to 516±248 µg · L−1 and 442±204 U · L−1, respectively (P<0.05) after the race. Pre- to post-race jump change did not correlate with dehydration (r = 0.16; P>0.05) but significantly correlated with myoglobin concentration (r = 0.65; P<0.001) and creatine kinase concentration (r = 0.54; P<0.001). Conclusions/significance During a half-iron distance triathlon, the capacity of leg muscles to produce force was notably diminished while arm muscle force output remained unaffected. Leg muscle fatigue was correlated with blood markers of muscle damage suggesting that muscle breakdown is one of the most relevant sources of muscle fatigue during a triathlon. PMID:22900101

Intermediate-range Nuclear Forces (INF) negotiations and treaty: An historical case study. Master's thesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wussler, D.E.

1989-09-01

This thesis performs detailed analysis of the Intermediate Range Nuclear Forces (INF) negotiations and treaty and compares them with those of the two Strategic Arms Limitations Talks (SALT). The study's objectives were: describe SALT and INF negotiations and the contents of the treaties; analyze US and Soviet goals and strategies during the INF negotiations; determine which goals were or were not attained by both sides, and ascertain reasons for this; and delineate arms control progress and prospects since INF Treaty ratification. The study found that the two SALT treaties did impose ceilings in certain areas of strategic weapons but didmore » not curtail the arms race. Treaty verification methods were criticized as being lax. The US achieved the major goal of ridding Europe of the Soviet SS-20 missile. It had to deploy missiles of its own to make the USSR realize the seriousness of its resolve. The US had total support from NATO in achieving this goal. However, with INF gone, the European conventional forces imbalance looms larger, and the West is fighting to obtain asymmetric conventional cuts.« less

Origin of the chromosomal radiation of Madeiran house mice: a microsatellite analysis of metacentric chromosomes

PubMed Central

Förster, D W; Mathias, M L; Britton-Davidian, J; Searle, J B

2013-01-01

Chromosome races of Mus musculus domesticus are characterised by particular sets of metacentric chromosomes formed by Robertsonian fusions and whole-arm reciprocal translocations. The Atlantic island of Madeira is inhabited by six chromosome races of house mice with 6–9 pairs of metacentric chromosomes. Three of these races are characterised by the metacentric 3.8 also found elsewhere in the distribution of M. m. domesticus, including Denmark and Spain. We investigated the possibility that metacentric 3.8 was introduced to Madeira during the initial colonisation, as this could have ‘seeded' the cascade of chromosomal mutation that is the basis of the extraordinary chromosomal radiation observed on the island. Variation at 24 microsatellite loci mapping to three different chromosomal regions (proximal, interstitial and distal) of mouse chromosomes 3 and 8 was investigated in 179 mice from Madeira, Denmark, Portugal, Spain, Italy and Scotland. Analyses of microsatellite loci closely linked to the centromeres of these chromosomes (‘proximal loci') do not support a common evolutionary origin of metacentric 3.8 among Madeiran, Danish and Spanish mouse populations. Our results suggest that Madeiran mice are genetically more similar to standard karyotype mice from Portugal than to metacentric mice from elsewhere. There is expected to be an interruption to gene flow between hybridising metacentric races on Madeira, particularly in the chromosomal regions close to the rearrangement breakpoints. Consistent with this, relating to differentiation involving chromosomes 3 and 8 on Madeira, we found greater genetic structure among races for proximal than interstitial or distal loci. PMID:23232832

Trafficking arms: oomycete effectors enter host plant cells.

PubMed

Birch, Paul R J; Rehmany, Anne P; Pritchard, Leighton; Kamoun, Sophien; Beynon, Jim L

2006-01-01

Oomycetes cause devastating plant diseases of global importance, yet little is known about the molecular basis of their pathogenicity. Recently, the first oomycete effector genes with cultivar-specific avirulence (AVR) functions were identified. Evidence of diversifying selection in these genes and their cognate plant host resistance genes suggests a molecular "arms race" as plants and oomycetes attempt to achieve and evade detection, respectively. AVR proteins from Hyaloperonospora parasitica and Phytophthora infestans are detected in the plant host cytoplasm, consistent with the hypothesis that oomycetes, as is the case with bacteria and fungi, actively deliver effectors inside host cells. The RXLR amino acid motif, which is present in these AVR proteins and other secreted oomycete proteins, is similar to a host-cell-targeting signal in virulence proteins of malaria parasites (Plasmodium species), suggesting a conserved role in pathogenicity.

Translations on Eastern Europe, Political, Sociological, and Military Affairs, Number 1503

DTIC Science & Technology

1978-02-15

secretary and State Council chairman. Kadar, Losonczi Message Budapest MAGYAR HIRLAP in Hungarian 26 Jan 78 p 4 AU ["Greetings Message by Janos Kadar and...delegates of the European Youth and Students Conference in Budapest . "In the face of the continuing arms race the extension of detente to the military...HUNGARY BOLDIZSAR, FRIENDS REACTION TO RETURN OF CROWN RELATED Budapest ELET ES IRODALOM in Hungarian 14 Jan 78 pp 5-6 [Article by Ivan Boldizsar

’Whiskey on the Rocks’ - The Submarine Incident off Karlskrona (’Whisky on the Rocks’ - Der U-Boot-Zwischefall vor Karlskrona),

DTIC Science & Technology

1982-04-19

kowledg tha hoediee e i sumrieoesgeufr umrednvgain sounded the arm to the "Oertogsbasstaben sic] in Karlskrona, whose chief of staff, Commander Karl...through: "Sweden--small--pfui--nothing, Soviet Union--great-- powerful ." Not quite diplomatic, but perhaps a measure of the master race mentality of...certain Soviet military people. Soviet Demonstration of Power When the alarm was sounded, all conceivable measures were taken by the Swedish commander𔃾n

International Communication and Confidence-Building in Europe. Report of the Leipzig-Tampere Seminar on Confidence-Building in the Non-Military Field (1st, Leipzig, East Germany, May 14-15, 1986). Publications Series B. 20/1986

ERIC Educational Resources Information Center

Kleinwachter, Wolfgang, Ed.; Nordenstreng, Kaarle, Ed.

Focusing on the role of the international mass media, these essays stress the urgency of building confidence in the relations among European states and populations in order to secure peace on a world-wide scale and to stop the arms race on the earth and prevent its extension to outer space. Titles and authors are as follows: (1) "Welcoming…

JPRS Report, Soviet Union, World Economy & International Relations, No. 12, December 1987

DTIC Science & Technology

1988-05-19

an anti-cyclic way by increasing investments in the years of crisis . The same must be said about the credit and financial system of the 80s and... crisis in the Persian Gulf zone it is largely due to US military activities. The author exposes the true motives of the American activity in the Persian...noting that three components are most visible: the arms race, fraught with global catastrophy, the accelerated ecological crisis caused by the

The long darkness: Psychological and moral perspectives on nuclear winter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grinspoon, L.

The aftermath of nuclear war - a sustained period of devastation called nuclear winter - would threaten the survival of civilization, even of the human species. In this book some opponents of the arms race describe the consequences of nuclear warfare and offer explanations - drawn from their knowledge of psychiatry, history, religion, and biology - for the irrational behavior of political leaders who risk these consequences and for the reluctance of ordinary citizens to face the horror of the nuclear threat.

The Strategic Context for Assessing Long Range Offense and Active Defense.

DTIC Science & Technology

1986-10-27

such Europeans do not really think that there is much of a Soviet nuclear threat to Western Europe, but d. hink that there is an American threat--or at...American military innovation has slowed down. It has been clear for many years that continuing references to a quantitative strategic arms race...have for a long time called for renewed efforts to " slow down the rate of weapons innovation" and "hence to reduce the frequency of introduction of

Living with the Devil: Stability in the 21st Century World With or Without Nuclear Weapons

DTIC Science & Technology

2012-03-01

author’s opinion - if we are not progressing, we must be falling behind . While an arms race is not desired, a strong and unwavering approach towards...than your congresses: on the day that two army corps can mutually annihilate each other in a second, all civilised nations will surely recoil with...we must thus consider this a driving force behind nuclear proliferation. Therefore, as diplomatic, political and social consequences continue to

Translations on USSR Military Affairs, Number 1309

DTIC Science & Technology

1977-10-17

correlation of forces in the world . In recent years, a turning away from the "cold war " to the re- laxation of tension and to the establishment of the...intensifying the arms race and trying to revive an atmosphere of confrontation and to return the world to the times of the "cold war ." 20 The...headed by V. I. Lenin, rose up for the decisive assault on the bourgeoisie- landlord system and crushed it. The first socialist state in the world

Balance of Power Theory: Implications for the U.S., Iran, Saudi Arabia, and a New Arms Race

DTIC Science & Technology

2008-06-01

37 Andre de Nesnera, "Experts Urge Direct U.S.-Iranian Talks to Resolve Nuclear Issue," Voice of America , April 28, 2006, <http://www.voanews.com...negotiations with the International Atomic Energy Agency in order to initiate their plans for developing nuclear energy. For more, see Peter C. Glover ...wealth while enabling the United States to withstand the Soviet threat and succeed as the sole remaining superpower. While this formula served America

Catholic doctrine and nuclear dogmatics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paradise, S.I.

The bishops' pastoral letter challenging US nuclear strategy is based on the moral doctrine of a just war and post-World War II anti-Communist developments within the church. They advocate non-violence and active pursuit of peace, but retain the just war theory. They interpret nuclear deterrence as morally flawed and a driving force in the arms race, but they offer a moral loophole by advocating only bilateral and verifiable disarmament. The controversy centers on how quickly Christians are obligated to act. 9 references. (DCK)

Roles of small RNAs in plant disease resistance.

PubMed

Yang, Li; Huang, Hai

2014-10-01

The interaction between plants and pathogens represents a dynamic competition between a robust immune system and efficient infectious strategies. Plant innate immunity is composed of complex and highly regulated molecular networks, which can be triggered by the perception of either conserved or race-specific pathogenic molecular signatures. Small RNAs are emerging as versatile regulators of plant development, growth and response to biotic and abiotic stresses. They act in different tiers of plant immunity, including the pathogen-associated molecular pattern-triggered and the effector-triggered immunity. On the other hand, pathogens have evolved effector molecules to suppress or hijack the host small RNA pathways. This leads to an arms race between plants and pathogens at the level of small RNA-mediated defense. Here, we review recent advances in small RNA-mediated defense responses and discuss the challenging questions in this area. © 2014 Institute of Botany, Chinese Academy of Sciences.

Memory-Based Multiagent Coevolution Modeling for Robust Moving Object Tracking

PubMed Central

Wang, Yanjiang; Qi, Yujuan; Li, Yongping

2013-01-01

The three-stage human brain memory model is incorporated into a multiagent coevolutionary process for finding the best match of the appearance of an object, and a memory-based multiagent coevolution algorithm for robust tracking the moving objects is presented in this paper. Each agent can remember, retrieve, or forget the appearance of the object through its own memory system by its own experience. A number of such memory-based agents are randomly distributed nearby the located object region and then mapped onto a 2D lattice-like environment for predicting the new location of the object by their coevolutionary behaviors, such as competition, recombination, and migration. Experimental results show that the proposed method can deal with large appearance changes and heavy occlusions when tracking a moving object. It can locate the correct object after the appearance changed or the occlusion recovered and outperforms the traditional particle filter-based tracking methods. PMID:23843739

Memory-based multiagent coevolution modeling for robust moving object tracking.

PubMed

Wang, Yanjiang; Qi, Yujuan; Li, Yongping

2013-01-01

The three-stage human brain memory model is incorporated into a multiagent coevolutionary process for finding the best match of the appearance of an object, and a memory-based multiagent coevolution algorithm for robust tracking the moving objects is presented in this paper. Each agent can remember, retrieve, or forget the appearance of the object through its own memory system by its own experience. A number of such memory-based agents are randomly distributed nearby the located object region and then mapped onto a 2D lattice-like environment for predicting the new location of the object by their coevolutionary behaviors, such as competition, recombination, and migration. Experimental results show that the proposed method can deal with large appearance changes and heavy occlusions when tracking a moving object. It can locate the correct object after the appearance changed or the occlusion recovered and outperforms the traditional particle filter-based tracking methods.

Multiagent Flight Control in Dynamic Environments with Cooperative Coevolutionary Algorithms

NASA Technical Reports Server (NTRS)

Knudson, Matthew D.; Colby, Mitchell; Tumer, Kagan

2014-01-01

Dynamic flight environments in which objectives and environmental features change with respect to time pose a difficult problem with regards to planning optimal flight paths. Path planning methods are typically computationally expensive, and are often difficult to implement in real time if system objectives are changed. This computational problem is compounded when multiple agents are present in the system, as the state and action space grows exponentially. In this work, we use cooperative coevolutionary algorithms in order to develop policies which control agent motion in a dynamic multiagent unmanned aerial system environment such that goals and perceptions change, while ensuring safety constraints are not violated. Rather than replanning new paths when the environment changes, we develop a policy which can map the new environmental features to a trajectory for the agent while ensuring safe and reliable operation, while providing 92% of the theoretically optimal performance

Co-evolution for Problem Simplification

NASA Technical Reports Server (NTRS)

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

1999-01-01

This paper explores a co-evolutionary approach applicable to difficult problems with limited failure/success performance feedback. Like familiar "predator-prey" frameworks this algorithm evolves two populations of individuals - the solutions (predators) and the problems (prey). The approach extends previous work by rewarding only the problems that match their difficulty to the level of solut,ion competence. In complex problem domains with limited feedback, this "tractability constraint" helps provide an adaptive fitness gradient that, effectively differentiates the candidate solutions. The algorithm generates selective pressure toward the evolution of increasingly competent solutions by rewarding solution generality and uniqueness and problem tractability and difficulty. Relative (inverse-fitness) and absolute (static objective function) approaches to evaluating problem difficulty are explored and discussed. On a simple control task, this co-evolutionary algorithm was found to have significant advantages over a genetic algorithm with either a static fitness function or a fitness function that changes on a hand-tuned schedule.

Integrating instance selection, instance weighting, and feature weighting for nearest neighbor classifiers by coevolutionary algorithms.

PubMed

Derrac, Joaquín; Triguero, Isaac; Garcia, Salvador; Herrera, Francisco

2012-10-01

Cooperative coevolution is a successful trend of evolutionary computation which allows us to define partitions of the domain of a given problem, or to integrate several related techniques into one, by the use of evolutionary algorithms. It is possible to apply it to the development of advanced classification methods, which integrate several machine learning techniques into a single proposal. A novel approach integrating instance selection, instance weighting, and feature weighting into the framework of a coevolutionary model is presented in this paper. We compare it with a wide range of evolutionary and nonevolutionary related methods, in order to show the benefits of the employment of coevolution to apply the techniques considered simultaneously. The results obtained, contrasted through nonparametric statistical tests, show that our proposal outperforms other methods in the comparison, thus becoming a suitable tool in the task of enhancing the nearest neighbor classifier.

Multiagent Flight Control in Dynamic Environments with Cooperative Coevolutionary Algorithms

NASA Technical Reports Server (NTRS)

Colby, Mitchell; Knudson, Matthew D.; Tumer, Kagan

2014-01-01

Dynamic environments in which objectives and environmental features change with respect to time pose a difficult problem with regards to planning optimal paths through these environments. Path planning methods are typically computationally expensive, and are often difficult to implement in real time if system objectives are changed. This computational problem is compounded when multiple agents are present in the system, as the state and action space grows exponentially with the number of agents in the system. In this work, we use cooperative coevolutionary algorithms in order to develop policies which control agent motion in a dynamic multiagent unmanned aerial system environment such that goals and perceptions change, while ensuring safety constraints are not violated. Rather than replanning new paths when the environment changes, we develop a policy which can map the new environmental features to a trajectory for the agent while ensuring safe and reliable operation, while providing 92% of the theoretically optimal performance.

Cuckoos, cowbirds and hosts: adaptations, trade-offs and constraints.

PubMed

Krüger, Oliver

2007-10-29

The interactions between brood parasitic birds and their host species provide one of the best model systems for coevolution. Despite being intensively studied, the parasite-host system provides ample opportunities to test new predictions from both coevolutionary theory as well as life-history theory in general. I identify four main areas that might be especially fruitful: cuckoo female gentes as alternative reproductive strategies, non-random and nonlinear risks of brood parasitism for host individuals, host parental quality and targeted brood parasitism, and differences and similarities between predation risk and parasitism risk. Rather than being a rare and intriguing system to study coevolutionary processes, I believe that avian brood parasites and their hosts are much more important as extreme cases in the evolution of life-history strategies. They provide unique examples of trade-offs and situations where constraints are either completely removed or particularly severe.

Environmental feedback drives cooperation in spatial social dilemmas

NASA Astrophysics Data System (ADS)

Szolnoki, Attila; Chen, Xiaojie

2017-12-01

Exploiting others is beneficial individually but it could also be detrimental globally. The reverse is also true: a higher cooperation level may change the environment in a way that is beneficial for all competitors. To explore the possible consequence of this feedback we consider a coevolutionary model where the local cooperation level determines the payoff values of the applied prisoner's dilemma game. We observe that the coevolutionary rule provides a significantly higher cooperation level comparing to the traditional setup independently of the topology of the applied interaction graph. Interestingly, this cooperation supporting mechanism offers lonely defectors a high surviving chance for a long period hence the relaxation to the final cooperating state happens logarithmically slow. As a consequence, the extension of the traditional evolutionary game by considering interactions with the environment provides a good opportunity for cooperators, but their reward may arrive with some delay.

Association of hand and arm disinfection with asthma control in US nurses.

PubMed

Dumas, Orianne; Varraso, Raphäelle; Boggs, Krislyn M; Descatha, Alexis; Henneberger, Paul K; Quinot, Catherine; Speizer, Frank E; Zock, Jan-Paul; Le Moual, Nicole; Camargo, Carlos A

2018-05-01

To investigate the association between occupational exposure to disinfectants/antiseptics used for hand hygiene and asthma control in nurses. In 2014, we invited female nurses with asthma drawn from the Nurses' Health Study II to complete two supplemental questionnaires on their occupation and asthma (cross-sectional study, response rate: 80%). Among 4055 nurses (mean age: 59 years) with physician-diagnosed asthma and asthma medication use in the past year, we examined asthma control, as defined by the Asthma Control Test (ACT). Nurses were asked about the daily frequency of hand hygiene tasks: 'wash/scrub hands with disinfectants/hand sanitizers' (hand hygiene) and 'wash/scrub arms with disinfecting products' (surrogate of surgical hand/arm antisepsis). Analyses were adjusted for age, race, ethnicity, smoking status and body mass index. Nurses with partly controlled asthma (ACT: 20-24, 50%) and poorly controlled asthma (ACT ≤19, 18%) were compared with nurses with controlled asthma (ACT=25, 32%). In separate models, both hand and arm hygiene were associated with poorly controlled asthma. After mutual adjustment, only arm hygiene was associated with poorly controlled asthma: OR (95% CI) for <1 time/day, 1.38 (1.06 to 1.80); ≥1 time/day, 1.96 (1.52 to 2.51), versus never. We observed a consistent dose-response relationship between frequency of arm hygiene tasks (never to >10 times/day) and poor asthma control. Associations persisted after further adjustment for surfaces/instruments disinfection tasks. Frequency of hand/arm hygiene tasks in nurses was associated with poor asthma control. The results suggest an adverse effect of products used for surgical hand/arm antisepsis. This potential new occupational risk factor for asthma warrants further study. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Sensor design for outdoor racing bicycle field testing for human vibration comfort evaluation

NASA Astrophysics Data System (ADS)

Vanwalleghem, Joachim; De Baere, Ives; Loccufier, Mia; Van Paepegem, Wim

2013-09-01

This paper is concerned with the vibrational comfort evaluation of the cyclist when cycling a rough surface. Outdoor comfort tests have so far only been done through instrumenting the bicycle with accelerometers. This work instruments a racing bicycle with custom-made contact force sensors and velocity sensors to acquire human comfort through the absorbed power method. Comfort evaluation is assessed at the hand-arm and seat interface of the cyclist with the bicycle. By means of careful finite-element analysis for designing the force gauges at the handlebar and the seat combined with precise calibration of both force and velocity sensors, all sensors have proven to work properly. Initial field tests are focused on the proper functioning of the designed sensors and their suitability for vibration comfort measurements. Tests on a cobblestone road reveal that the outcome of the absorbed power values is within the same range as those from laboratory tests found in the literature. This sensor design approach for outdoor testing with racing bicycles may give a new interpretation on evaluating the cyclist's comfort since the vibrational load is not only quantified in terms of acceleration but also in terms of force and velocity at the bicycle-cyclist contact points.

Contact zone between chromosomal races of Mus musculus domesticus. 2. Fertility and segregation in laboratory-reared and wild mice heterozygous for multiple robertsonian rearrangements.

PubMed

Castiglia, R; Capanna, E

2000-08-01

Litter size, anaphase I nondisjunction and X-Y dissociation at metaphase I were studied in homozygous and heterozygous house mice from a central Italian chromosomal hybrid zone between the CD (2n=22) race and the standard race (2n=40). We also observed the segregation of the two chromosomal forms (Robertsonian and non-Robertsonian) in male and female multiple heterozygotes from the karyotype of their offspring and chromosomal arm counts of metaphase II. Litter size was significantly reduced in the F1 hybrids, but there was no difference in litter size between male and female F1s. Fertility in wild mice decreased with increasing numbers of structural heterozygosities (0-5). Some metacentrics appear to be under meiotic drive but there was no rule as to which of the two forms was favoured in backcrosses. An original observation of a negative correlation between the length of metacentrics and transmission rate was described in hybrids. Slight cosegregation of chromosomes with a similar morphology was present in the progeny of males and females. These observations are discussed in relation to the stability of this hybrid zone through time.

An analysis of the blood pressure and safety outcomes to renal denervation in African Americans and Non-African Americans in the SYMPLICITY HTN-3 trial.

PubMed

Flack, John M; Bhatt, Deepak L; Kandzari, David E; Brown, David; Brar, Sandeep; Choi, James W; D'Agostino, Ralph; East, Cara; Katzen, Barry T; Lee, Lilian; Leon, Martin B; Mauri, Laura; O'Neill, William W; Oparil, Suzanne; Rocha-Singh, Krishna; Townsend, Raymond R; Bakris, George

2015-10-01

SYMPLICITY HTN-3, the first trial of renal denervation (RDN) versus sham, enrolled 26% African Americans, a prospectively stratified cohort. Although the 6-month systolic blood pressure (SBP) reduction in African Americans (AAs) was similar in the RDN group (-15.5 ± 25.4 mm Hg, n = 85 vs. -17.8 ± 29.2, n = 49, P = .641), the sham SBP response was 9.2 mm Hg greater (P = .057) in AAs than non-AAs. In multivariate analyses, sham SBP response was predicted by an interaction between AA and a complex antihypertensive regimen (at least one antihypertensive medication prescribed ≥3 times daily), while in the RDN group, SBP response was predicted by an interaction between AA race and baseline BP ≥ 180 mm Hg. AA race did not independently predict SBP response in either sham or RDN. There appears to be effect modification by race with individual-level patient characteristics in both treatment arms that affect the observed pattern of SBP responses. Copyright © 2015 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

A new index of flat breaststroke propulsion: a comparison of elite men and women.

PubMed

Seifert, L; Chollet, D

2005-03-01

This study examined arm and leg coordination and propulsion during the flat breaststroke in nine elite male and eight elite female swimmers over three race paces (200 m, 100 m and 50 m). Coordination was expressed using four temporal gaps (T1, T2, T3, T4), which described the continuity between the propulsive phases of the limbs, as recorded on a video device (50 Hz). Glide duration was denoted T1, the time between the beginning of arm and leg recovery was denoted T2, the time between the end of arm and the leg recovery was denoted T3, and the time between 90 degrees of flexion during arm recovery and 90 degrees during leg recovery was denoted T4. Using these temporal gaps, four stroke phases (propulsion, glide, recovery and leg insweep) could be followed over a complete arm and leg stroke. The total duration of arm and leg propulsion was assessed by a new index of flat breaststroke propulsion (IFBP). Velocity, stroke rate and stroke length were also calculated for each pace. The elite swimmers showed short T2, T3 and T4; moreover, T1 decreased when the pace increased. Expertise in the flat breaststroke was thus characterized by synchronized arm and leg recoveries and increased continuity in the arm and leg propulsions with increasing velocity. Differences between the sexes in the spatio-temporal parameters were possibly due to anthropometric differences (the men were heavier, older and taller than the women) and different motor organization linked to arm and leg coordination (shorter T3, body glide and body recovery, and greater body propulsion and higher IFBP in the men). The men's propulsive actions showed greater continuity, particularly in the sprint. The best men adopted a superposition coordination and thus had the ability to overcome very great active drag. Temporal gap measurement and the IFBP are practical indicators of arm and leg coordination and propulsion that can be exploited by coaches and swimmers to increase the continuity between propulsive actions during the flat breaststroke.

Racial differences in virologic failure associated with adherence and quality of life on efavirenz-containing regimens for initial HIV therapy: results of ACTG A5095.

PubMed

Schackman, Bruce R; Ribaudo, Heather J; Krambrink, Amy; Hughes, Valery; Kuritzkes, Daniel R; Gulick, Roy M

2007-12-15

Blacks had higher rates of virologic failure than whites on efavirenz-containing regimens in the AIDS Clinical Trials Group (ACTG) A5095 study; preliminary analyses also suggested an association with adherence. We rigorously examined associations over time among race, virologic failure, 4 self-reported adherence metrics, and quality of life (QOL). ACTG A5095 was a double-blind placebo-controlled study of treatment-naive HIV-positive patients randomized to zidovudine/lamivudine/abacavir versus zidovudine/lamivudine plus efavirenz versus zidovudine/lamivudine/abacavir plus efavirenz. Virologic failure was defined as confirmed HIV-1 RNA >or=200 copies/mL at >or=16 weeks on study. The zidovudine/lamivudine/abacavir arm was discontinued early because of virologic inferiority. We examined virologic failure differences for efavirenz-containing arms according to missing 0 (adherent) versus at least 1 dose (nonadherent) during the past 4 days, alternative self-reported adherence metrics, and QOL. Analyses used the Fisher exact, log rank tests, and Cox proportional hazards models. The study population included white (n = 299), black (n = 260), and Hispanic (n = 156) patients with >or=1 adherence evaluation. Virologic failure was associated with week 12 nonadherence during the past 4 days for blacks (53% nonadherent failed vs. 25% adherent; P < 0.001) but not for whites (20% nonadherent failed vs. 20% adherent; P = 0.91). After adjustment for baseline covariates and treatment, there was a significant interaction between race and week 12 adherence (P = 0.02). In time-dependent Cox models using self-reports over time to reflect recent adherence, there was a significantly higher failure risk for nonadherent subjects (hazard ratio [HR] = 2.07; P < 0.001). Significant race-adherence interactions were seen in additional models of adherence: missing at least 1 medication dose ever (P = 0.04), past month (P < 0.01), or past weekend (P = 0.05). Lower QOL was significantly associated with virologic failure (P < 0.001); there was no evidence of an interaction between QOL and race (P = 0.39) or adherence (P = 0.51) in predicting virologic failure. There was a greater effect of nonadherence on virologic failure in blacks given efavirenz-containing regimens than in whites. Self-reported adherence and QOL are independent predictors of virologic failure.

Predictors of retention and attrition in a study of an advanced upper limb prosthesis: implications for adoption of the DEKA Arm.

PubMed

Resnik, Linda; Cancio, Jill; Klinger, Shana; Latlief, Gail; Sasson, Nicole; Smurr-Walters, Lisa

2018-02-01

The purpose was to identify factors associated with completion of the VA home study of the DEKA Arm. Design and methodological procedures used: Differences between groups were examined using chi-square and t-tests. A multivariable logistic regression model predicting completion was generated and odds ratios (OR) for significant variables calculated. Post-hoc analysis was performed to plot the receiver operating characteristics (ROC) curve. Participants who completed were more likely to be prosthesis users at study onset (p = .03), and less likely to have a history of musculoskeletal problems (p = .047). There were no statistically significant differences between groups who completed and those who did not in gender, race, veteran status, age, body mass index (BMI), weight, height, musculoskeletal pain at baseline, satisfaction with current prosthesis, type of prosthesis, or months of prosthesis use. Two variables, prosthesis use and history of musculoskeletal problems were significant at p < .10. The area under the curve (AUC) accuracy index was 0.78. We considered completion of the home use study a reasonable proxy for participant willingness to adopt the device; and believe that findings can be extrapolated to guide DEKA Arm prescription recommendations. Participants most likely to complete the study were already using a personal prosthesis, and without pre-existing musculoskeletal problems. Implications for rehabilitation Data from the VA Study of the DEKA Arm were analysed to determine which factors were associated with likely successful adoption of the DEKA Arm. Participants most likely to complete the study were those who already using a personal prosthesis, and those without pre-existing chronic or re-occurring musculoskeletal problems. This information may be useful when attempting to identify and target the most appropriate candidates for DEKA Arm prescription.

Physics and technology of the arms race

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garwin, R.L.

1983-01-01

Traditional military concepts of superiority and effectiveness (as embodied in Lanchester's law) have little relevance to thermonuclear weapons, with their enormous effectiveness in destruction of society. Few are needed to saturate their deterrent effect, but their military effectiveness is limited. The evolution and future of strategic nuclear forces is discussed, and their declining marginal utility emphasized. Some calculations relevant to the nuclear confrontation are presented (Lanchester's Law; skin effect of VLF and ELF signals to submarines; the rocket equation; simple radar-range equation) and recommendations presented for future strategic forces and arms control initiatives. Recommended programs include a silo-based 12-ton single-warheadmore » missile (SICM), the development of buried-bomb defense of individual Minuteman silos, the completion of the deployment of air-launched cruise missiles on the B-52 fleet, and the development of small (1000-ton) submarines for basing ICBM-range missiles.« less

Analysis of a front suspension system for UniART FSAE car using FEA

NASA Astrophysics Data System (ADS)

Zaidie, M. N. A.; Hashim, M. S. M.; Tasyrif, M.; Basha, M. H.; Ibrahim, I.; Kamaruddin, N. S.; Shahriman, A. B.

2017-10-01

In recent years, many research works from institutions that participated in Formula SAE had highlighted on suspension systems. The aim is to improve the system in term of performance and robustness. However, every suspension system for a racing car is tailored to the car itself. Thus, this paper proposes a new design for front suspension system for UniART FSAE car. The new design was than being compared to the previous suspension system for enhancement. The analysis covered in this paper based on several conditions such as braking, cornering and bumping condition and was carried out using finite element analysis. Each main component for the suspension system such as lower arm, upper arm and knuckle has been analysed in term of strength and performance. From the results, the proposed new design of the suspension system has improved in term of strength and performance compared to the previous suspension system.

Can we predict body height from segmental bone length measurements? A study of 3,647 children.

PubMed

Cheng, J C; Leung, S S; Chiu, B S; Tse, P W; Lee, C W; Chan, A K; Xia, G; Leung, A K; Xu, Y Y

1998-01-01

It is well known that significant differences exist in the anthropometric data of different races and ethnic groups. This is a cross-sectional study on segmental bone length based on 3,647 Chinese children of equal sex distribution aged 3-18 years. The measurements included standing height, weight, arm span, foot length, and segmental bone length of the humerus, radius, ulna, and tibia. A normality growth chart of all the measured parameters was constructed. Statistical analysis of the results showed a very high linear correlation of height with arm span, foot length, and segmental bone lengths with a correlation coefficient of 0.96-0.99 for both sexes. No differences were found between the right and left side of all the segmental bone lengths. These Chinese children were found to have a proportional limb segmental length relative to the trunk.

Macroevolutionary chemical escalation in an ancient plant-herbivore arms race.

PubMed

Becerra, Judith X; Noge, Koji; Venable, D Lawrence

2009-10-27

A central paradigm in the field of plant-herbivore interactions is that the diversity and complexity of secondary compounds in plants have intensified over evolutionary time, resulting in the great variety of secondary products that currently exists. Unfortunately, testing of this proposal has been very limited. We analyzed the volatile chemistry of 70 species of the tropical plant genus Bursera and used a molecular phylogeny to test whether the species' chemical diversity or complexity have escalated. The results confirm that as new species diverged over time they tended to be armed not only with more compounds/species, but also with compounds that could potentially be more difficult for herbivores to adapt to because they belong to an increasing variety of chemical pathways. Overall chemical diversity in the genus also increased, but not as fast as species diversity, possibly because of allopatric species gaining improved defense with compounds that are new locally, but already in existence elsewhere.

Impact of Race, Ethnicity and BMI on Achievement of Pathologic Complete Response Following Neoadjuvant Chemotherapy for Breast Cancer: A Pooled Analysis of Four Prospective Alliance Clinical Trials (A151426)

PubMed Central

Warner, Erica T.; Ballman, Karla V.; Strand, Carrie; Boughey, Judy; Buzdar, Aman U.; Carey, Lisa A.; Sikov, William M.; Partridge, H.

2016-01-01

Purpose Previous studies demonstrated poor response to neoadjuvant systemic therapy (NST) for breast cancer among black women and women who are overweight or obese but this may be due to chemotherapy under dosing. We assessed associations of race, ethnicity and body mass index (BMI) with pathologic complete response (pCR) in clinical trial populations. Methods 1797 women enrolled in four NST trials (CALGB 40601, 40603; ACOSOG Z1041, Z1071) were included. Tumor subtypes were defined by estrogen receptor (ER) and HER2 status. Logistic regression generated odds ratios (OR) and 95% confidence intervals (CI) for the associations of race, ethnicity, and BMI with pCR adjusting for subtype, study arm, lymph node status, tumor size, and tumor grade. Results 253 (14.1%) were black, 199 (11.1%) Hispanic, 520 (28.9%) overweight, and 743 (41.4%) obese. Compared to whites, Blacks and Hispanics were more likely to be obese and Blacks were more likely to have triple-negative cancer. pCR rates differed significantly by tumor subtype. In multivariate analyses, neither race (black vs. white: OR: 1.18, 95% CI: 0.85–1.62) nor ethnicity (Hispanic vs. non-Hispanic: OR: 1.30, 95% CI: 0.67–2.53) were significant predictors of pCR overall or by subtype. Overweight and obese women had lower pCR rates in ER+/HER2+, but higher pCR rates in ER−/HER2+ cancers. Conclusions There was no difference in breast pCR according to race or ethnicity. Overall, there was no major difference in pCR rates by BMI. These findings suggest that pCR with optimally dosed NST is a function of tumor, rather than patient, biology. PMID:27449492

Impact of race, ethnicity, and BMI on achievement of pathologic complete response following neoadjuvant chemotherapy for breast cancer: a pooled analysis of four prospective Alliance clinical trials (A151426).

PubMed

Warner, Erica T; Ballman, Karla V; Strand, Carrie; Boughey, Judy C; Buzdar, Aman U; Carey, Lisa A; Sikov, William M; Partridge, Ann H

2016-08-01

Previous studies demonstrated poor response to neoadjuvant systemic therapy (NST) for breast cancer among black women and women who are overweight or obese, but this may be due to chemotherapy underdosing. We assessed associations of race, ethnicity, and body mass index (BMI) with pathologic complete response (pCR) in clinical trial populations. 1797 women enrolled in four NST trials (CALGB 40601, 40603; ACOSOG Z1041, Z1071) were included. Tumor subtypes were defined by estrogen receptor (ER) and HER2 status. Logistic regression generated odds ratios (OR) and 95 % confidence intervals (CI) for the associations of race, ethnicity, and BMI with in-breast pCR adjusting for subtype, study arm, lymph node status, tumor size, and tumor grade. 253 (14.1 %) were black, 199 (11.1 %) Hispanic, 520 (28.9 %) overweight, and 743 (41.4 %) obese. Compared to whites, Blacks and Hispanics were more likely to be obese and Blacks were more likely to have triple-negative cancer. pCR rates differed significantly by tumor subtype. In multivariate analyses, neither race (black vs white: OR 1.18, 95 % CI 0.85-1.62) nor ethnicity (Hispanic vs non-Hispanic; OR 1.30, 95 % CI 0.67-2.53) were significant predictors of pCR overall or by subtype. Overweight and obese women had lower pCR rates in ER+/HER2+, but higher pCR rates in ER-/HER2+ cancers. There was no difference in pCR according to race or ethnicity. Overall, there was no major difference in pCR rates by BMI. These findings suggest that pCR with optimally dosed NST is a function of tumor, rather than patient, biology.

Comparison of anthropometric and training characteristics between recreational male marathoners and 24-hour ultramarathoners.

PubMed

Rüst, Christoph Alexander; Knechtle, Beat; Knechtle, Patrizia; Rosemann, Thomas

2012-01-01

Of the anthropometry and training variables used to predict race performance in a 24-hour ultrarun, the personal best marathon time is the strongest predictor in recreational male 24-hour ultramarathoners. This finding raises the question of whether similarities exist between male recreational 24-hour ultramarathoners and male recreational marathoners. The association between age, anthropometric variables (ie, body mass, body height, body mass index, percent body fat, skeletal muscle mass, limb circumference, and skinfold thickness at the pectoral, mid axillary, triceps, subscapular, abdominal, suprailiac, front thigh, and medial calf sites), previous experience and training characteristics (ie, volume, speed, and personal best time), and race time for 79 male recreational 24-hour ultramarathoners and 126 male recreational marathoners was investigated using bivariate and multivariate analysis. The 24-hour ultramarathoners were older (P < 0.05), had a lower circumference at both the upper arm (P < 0.05) and thigh (P < 0.01), and a lower skinfold thickness at the pectoral, axillary, and suprailiac sites (P < 0.05) compared with the marathoners. During training, the 24-hour ultramarathoners were running for more hours per week (P < 0.001) and completed more kilometers (P < 0.001), but were running slower (P < 0.01) compared with the marathoners. In the 24-hour ultramarathoners, neither anthropometric nor training variables were associated with kilometers completed in the race (P > 0.05). In the marathoners, percent body fat (P < 0.001) and running speed during training (P < 0.0001) were related to marathon race times. In summary, differences in anthropometric and training predictor variables do exist between male recreational 24-hour ultramarathoners and male recreational marathoners for race performance.

Comparison of anthropometric and training characteristics between recreational male marathoners and 24-hour ultramarathoners

PubMed Central

Rüst, Christoph Alexander; Knechtle, Beat; Knechtle, Patrizia; Rosemann, Thomas

2012-01-01

Background Of the anthropometry and training variables used to predict race performance in a 24-hour ultrarun, the personal best marathon time is the strongest predictor in recreational male 24-hour ultramarathoners. This finding raises the question of whether similarities exist between male recreational 24-hour ultramarathoners and male recreational marathoners. Methods The association between age, anthropometric variables (ie, body mass, body height, body mass index, percent body fat, skeletal muscle mass, limb circumference, and skinfold thickness at the pectoral, mid axillary, triceps, subscapular, abdominal, suprailiac, front thigh, and medial calf sites), previous experience and training characteristics (ie, volume, speed, and personal best time), and race time for 79 male recreational 24-hour ultramarathoners and 126 male recreational marathoners was investigated using bivariate and multivariate analysis. Results The 24-hour ultramarathoners were older (P < 0.05), had a lower circumference at both the upper arm (P < 0.05) and thigh (P < 0.01), and a lower skinfold thickness at the pectoral, axillary, and suprailiac sites (P < 0.05) compared with the marathoners. During training, the 24-hour ultramarathoners were running for more hours per week (P < 0.001) and completed more kilometers (P < 0.001), but were running slower (P < 0.01) compared with the marathoners. In the 24-hour ultramarathoners, neither anthropometric nor training variables were associated with kilometers completed in the race (P > 0.05). In the marathoners, percent body fat (P < 0.001) and running speed during training (P < 0.0001) were related to marathon race times. Conclusion In summary, differences in anthropometric and training predictor variables do exist between male recreational 24-hour ultramarathoners and male recreational marathoners for race performance. PMID:24198595

Complementary epistasis involving Sr12 explains adult plant resistance to stem rust in Thatcher wheat (Triticum aestivum L.).

PubMed

Rouse, Matthew N; Talbert, Luther E; Singh, Davinder; Sherman, Jamie D

2014-07-01

Quantitative trait loci conferring adult plant resistance to Ug99 stem rust in Thatcher wheat display complementary gene action suggesting multiple quantitative trait loci are needed for effective resistance. Adult plant resistance (APR) in wheat (Triticum aestivum L.) to stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is desirable because this resistance can be Pgt race non-specific. Resistance derived from cultivar Thatcher can confer high levels of APR to the virulent Pgt race TTKSK (Ug99) when combined with stem rust resistance gene Sr57 (Lr34). To identify the loci conferring APR in Thatcher, we evaluated 160 RILs derived from Thatcher crossed to susceptible cultivar McNeal for field stem rust reaction in Kenya for two seasons and in St. Paul for one season. All RILs and parents were susceptible as seedlings to race TTKSK. However, adult plant stem rust severities in Kenya varied from 5 to 80 %. Composite interval mapping identified four quantitative trait loci (QTL). Three QTL were inherited from Thatcher and one, Sr57, was inherited from McNeal. The markers closest to the QTL peaks were used in an ANOVA to determine the additive and epistatic effects. A QTL on 3BS was detected in all three environments and explained 27-35 % of the variation. The peak of this QTL was at the same location as the Sr12 seedling resistance gene effective to race SCCSC. Epistatic interactions were significant between Sr12 and QTL on chromosome arms 1AL and 2BS. Though Sr12 cosegregated with the largest effect QTL, lines with Sr12 were not always resistant. The data suggest that Sr12 or a linked gene, though not effective to race TTKSK alone, confers APR when combined with other resistance loci.

New wheat-rye 5DS-4RS·4RL and 4RS-5DS·5DL translocation lines with powdery mildew resistance.

PubMed

Fu, Shulan; Ren, Zhenglong; Chen, Xiaoming; Yan, Benju; Tan, Feiquan; Fu, Tihua; Tang, Zongxiang

2014-11-01

Powdery mildew is one of the serious diseases of wheat (Triticum aestivum L., 2 n = 6 × = 42, genomes AABBDD). Rye (Secale cereale L., 2 n = 2 × = 14, genome RR) offers a rich reservoir of powdery mildew resistant genes for wheat breeding program. However, extensive use of these resistant genes may render them susceptible to new pathogen races because of co-evolution of host and pathogen. Therefore, the continuous exploration of new powdery mildew resistant genes is important to wheat breeding program. In the present study, we identified several wheat-rye addition lines from the progeny of T. aestivum L. Mianyang11 × S. cereale L. Kustro, i.e., monosomic addition lines of the rye chromosomes 4R and 6R; a disomic addition line of 6R; and monotelosomic or ditelosomic addition lines of the long arms of rye chromosomes 4R (4 RL) and 6R (6 RL). All these lines displayed immunity to powdery mildew. Thus, we concluded that both the 4 RL and 6 RL arms of Kustro contain powdery mildew resistant genes. It is the first time to discover that 4 RL arm carries powdery mildew resistant gene. Additionally, wheat lines containing new wheat-rye translocation chromosomes were also obtained: these lines retained a short arm of wheat chromosome 5D (5 DS) on which rye chromosome 4R was fused through the short arm 4 RS (designated 5 DS-4 RS · 4 RL; 4 RL stands for the long arm of rye chromosome 4R); or they had an extra short arm of rye chromosome 4R (4 RS) that was attached to the short arm of wheat chromosome 5D (5 DS) (designated 4 RS-5 DS · 5 DL; 5 DL stands for the long arm of wheat chromosome 5D). These two translocation chromosomes could be transmitted to next generation stably, and the wheat lines containing 5 DS-4 RS · 4 RL chromosome also displayed immunity to powdery mildew. The materials obtained in this study can be used for wheat powdery mildew resistant breeding program.

Xerostomia health-related quality of life: NRG oncology RTOG 0537.

PubMed

Wyatt, Gwen; Pugh, Stephanie L; Wong, Raimond K W; Sagar, Stephen; Singh, Anurag K; Koyfman, Shlomo A; Nguyen-Tân, Phuc F; Yom, Sue S; Cardinale, Francis S; Sultanem, Khalil; Hodson, Ian; Krempl, Greg A; Lukaszczyk, Barbara; Yeh, Alexander M; Berk, Lawrence

2016-09-01

The purpose of this secondary analysis was to determine change in overall health-related quality of life (HRQOL) based on patient data obtained from NRG Oncology RTOG 0537 as measured by the RTOG-modified University of Washington Head and Neck Symptom Score (RM-UWHNSS). A multi-site prospective randomized clinical trial design stratified 137 patients with post-radiation therapy xerostomia according to prior pilocarpine (PC) treatment and time after radiation therapy and/or chemotherapy and randomized patients into two groups. Patients were assigned to acupuncture or PC. Twenty-four sessions of acupuncture-like transcutaneous electrical nerve stimulation (ALTENS) were administered over 12 weeks, or oral PC (5 mg) three times daily over the same 12 weeks. The RM-UWHNSS was administered at baseline and at 4, 6, 9, and 15 months after the date of randomization. There were no between-arm differences in change scores on the RM-UWHNSS in the individual items, total score, or factor scores. For statistical modeling, race and time were significant for all outcomes (total and factor scores), while treatment arm was not significant. The ALTENS arm showed greater yet nonsignificant improvement in outcomes compared to the PC arm. Although no significant treatment differences were seen in this trial, patients receiving ALTENS consistently had lower scores, indicating better function, as compared to those receiving PC. Radiation-induced xerostomia improved over time for all patients.

Physics and technology of the arms race

NASA Astrophysics Data System (ADS)

Garwin, R. L.

1983-10-01

Traditional military concepts of superiority and effectiveness (as embodied in Lanchester's law) have little relevance to thermonuclear weapons, with their enormous effectiveness in destruction of society. Few are needed to saturate their deterrent effect, but their military effectiveness is limited. The evolution and future of strategic nuclear forces is discussed, and their declining marginal utility emphasized. Some calculatons relevant to the nuclear confrontation are presented (Lanchester's Law; skin effect of VLF and ELF signals to submarines; the rocket equation; simple radar-range equation) and recommendations presented for future strategic forces and arms control initiatives. Recommended programs include a silo-based 12-ton single-warhead missile (SICM), the development of buried-bomb defense of individual Minuteman silos, the completion of the deployment of air-launched cruise missiles on the B-52 fleet, and the development of small (1000-ton) submarines for basing ICBM-range missiles. Limiting the threat by arms control should include ratification of SALT II, followed by negotiation of a protrocool to allow a SICM and dedicated silo to be deployed for each two, SALT-II-allowed warheads given up; a ban on weapons in space and anti-satellite tests; and an eventual reduction to 1000 nuclear warheads in U.S. and Soviet inventories.

A RANDOMIZED TREATMENT TRIAL: SINGLE VERSUS 7 DAY DOSE OF METRONIDAZOLE FOR THE TREATMENT OF TRICHOMONAS VAGINALIS AMONG HIV-INFECTED WOMEN

PubMed Central

Kissinger, Patricia; Mena, Leandro; Levison, Judy; Clark, Rebecca A.; Gatski, Megan; Henderson, Harold; Schmidt, Norine; Rosenthal, Susan; Myers, Leann; Martin, David H.

2010-01-01

Objective To determine if the metronidazole (MTZ) 2 gm single dose (recommended) is as effective as the 7 day 500 mg BID dose (alternative) for treatment of Trichomonas vaginalis (TV) among HIV+ women. Methods Phase IV randomized clinical trial; HIV+ women with culture confirmed TV were randomized to treatment arm: MTZ 2 gm single dose or MTZ 500 mg BID 7 day dose. All women were given 2 gm MTZ doses to deliver to their sex partners. Women were re-cultured for TV at a test-of-cure (TOC) visit occurring 6-12 days after treatment completion. TV-negative women at TOC were again re-cultured at a 3 month visit. Repeat TV infection rates were compared between arms. Results 270 HIV+/TV+ women were enrolled (mean age = 40 years, ± 9.4; 92.2% African-American). Treatment arms were similar with respect to age, race, CD4 count, viral load, ART status, site, and loss-to-follow up. Women in the 7 day arm had: lower repeat TV infection rates at TOC [8.5% (11/130) versus 16.8% (21/125) (R.R. 0.50, 95% CI=0.25, 1.00; P<0.05)], and at 3 months [11.0% (8/73) versus 24.1% (19/79) (R.R. 0.46, 95% CI=0.21, 0.98; P=0.03)] compared to the single dose arm. Conclusions The 7 day MTZ dose was more effective than the single dose for the treatment of TV among HIV+ women. PMID:21423852

Genetics and mapping of a new anthracnose resistance locus in Andean common bean Paloma.

PubMed

de Lima Castro, Sandra Aparecida; Gonçalves-Vidigal, Maria Celeste; Gilio, Thiago Alexandre Santana; Lacanallo, Giselly Figueiredo; Valentini, Giseli; da Silva Ramos Martins, Vanusa; Song, Qijian; Galván, Marta Zulema; Hurtado-Gonzales, Oscar P; Pastor-Corrales, Marcial Antonio

2017-04-18

The Andean cultivar Paloma is resistant to Mesoamerican and Andean races of Colletotrichum lindemuthianum, the fungal pathogen that causes the destructive anthracnose disease in common bean. Remarkably, Paloma is resistant to Mesoamerican races 2047 and 3481, which are among the most virulent races of the anthracnose pathogen. Most genes conferring anthracnose resistance in common bean are overcome by these races. The genetic mapping and the relationship between the resistant Co-Pa gene of Paloma and previously characterized anthracnose resistance genes can be a great contribution for breeding programs. The inheritance of resistance studies for Paloma was performed in F 2 population from the cross Paloma (resistant) × Cornell 49-242 (susceptible) inoculated with race 2047, and in F 2 and F 2:3 generations from the cross Paloma (resistant) × PI 207262 (susceptible) inoculated with race 3481. The results of these studies demonstrated that a single dominant gene confers the resistance in Paloma. Allelism tests performed with multiple races of C. lindemuthianum showed that the resistance gene in Paloma, provisionally named Co-Pa, is independent from the anthracnose resistance genes Co-1, Co-2, Co-3, Co-4, Co-5, Co-6, Co-12, Co-13, Co-14, Co-15 and Co-16. Bulk segregant analysis using the SNP chip BARCBean6K_3 positioned the approximate location of Co-Pa in the lower arm of chromosome Pv01. Further mapping analysis located the Co-Pa gene at a 390 kb region of Pv01 flanked by SNP markers SS82 and SS83 at a distance of 1.3 and 2.1 cM, respectively. The results presented here showed that Paloma cultivar has a new dominant gene conferring resistance to anthracnose, which is independent from those genes previously described. The linkage between the Co-Pa gene and the SS82 and SS83 SNP markers will be extremely important for marker-assisted introgression of the gene into elite cultivars in order to enhance resistance.

Dietary Weight Loss and Exercise Effects on Serum Biomarkers of Angiogenesis in Overweight Postmenopausal Women: A Randomized Controlled Trial.

PubMed

Duggan, Catherine; Tapsoba, Jean de Dieu; Wang, Ching-Yun; McTiernan, Anne

2016-07-15

Obese and sedentary persons have an increased risk for cancer, but underlying mechanisms are poorly understood. Angiogenesis is common to adipose tissue formation and remodeling, and to tumor vascularization. A total of 439 overweight/obese, healthy, postmenopausal women [body mass index (BMI) > 25 kg/m(2)] ages 50-75 years, recruited between 2005 and 2008 were randomized to a 4-arm 12-month randomized controlled trial, comparing a caloric restriction diet arm (goal: 10% weight loss, N = 118), aerobic exercise arm (225 minutes/week of moderate-to-vigorous activity, N = 117), a combined diet + exercise arm (N = 117), or control (N = 87) on circulating levels of angiogenic biomarkers. VEGF, plasminogen activator inhibitor-1 (PAI-1), and pigment epithelium-derived factor (PEDF) were measured by immunoassay at baseline and 12 months. Changes were compared using generalized estimating equations, adjusting for baseline BMI, age, and race/ethnicity. Participants randomized to the diet + exercise arms had statistically significantly greater reductions in PAI-1 at 12 months compared with controls (-19.3% vs. +3.48%, respectively, P < 0.0001). Participants randomized to the diet and diet + exercise arms had statistically significantly greater reductions in PEDF (-9.20%, -9.90%, respectively, both P < 0.0001) and VEGF (-8.25%, P = 0.0005; -9.98%, P < 0.0001, respectively) compared with controls. There were no differences in any of the analytes in participants randomized to the exercise arm compared with controls. Increasing weight loss was statistically significantly associated with linear trends of greater reductions in PAI-1, PEDF, and VEGF. Weight loss is significantly associated with reduced circulating VEGF, PEDF, and PAI-1, and could provide incentive for reducing weight as a cancer prevention method in overweight and obese individuals. Cancer Res; 76(14); 4226-35. ©2016 AACR. ©2016 American Association for Cancer Research.

Detection of significant protein coevolution.

PubMed

Ochoa, David; Juan, David; Valencia, Alfonso; Pazos, Florencio

2015-07-01

The evolution of proteins cannot be fully understood without taking into account the coevolutionary linkages entangling them. From a practical point of view, coevolution between protein families has been used as a way of detecting protein interactions and functional relationships from genomic information. The most common approach to inferring protein coevolution involves the quantification of phylogenetic tree similarity using a family of methodologies termed mirrortree. In spite of their success, a fundamental problem of these approaches is the lack of an adequate statistical framework to assess the significance of a given coevolutionary score (tree similarity). As a consequence, a number of ad hoc filters and arbitrary thresholds are required in an attempt to obtain a final set of confident coevolutionary signals. In this work, we developed a method for associating confidence estimators (P values) to the tree-similarity scores, using a null model specifically designed for the tree comparison problem. We show how this approach largely improves the quality and coverage (number of pairs that can be evaluated) of the detected coevolution in all the stages of the mirrortree workflow, independently of the starting genomic information. This not only leads to a better understanding of protein coevolution and its biological implications, but also to obtain a highly reliable and comprehensive network of predicted interactions, as well as information on the substructure of macromolecular complexes using only genomic information. The software and datasets used in this work are freely available at: http://csbg.cnb.csic.es/pMT/. pazos@cnb.csic.es Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

In Memoriam: Hans Bethe

NASA Astrophysics Data System (ADS)

Garwin, Richard L.; Von Hippel, Frank

Hans Bethe, who died on March 6 at the age of 98, was exemplary as a scientist; a citizen-advocate seeking to stem the arms race; and an individual of warmth, generosity, tenacity, and modest habits. Bethe made major contributions to several areas of physics during his academic career. He earned a Nobel Prize in 1967 for his research into how the sun generates its energy by converting hydrogen to helium using carbon as a nuclear catalyst. A few years later, he made central contributions to the secret US World War II nuclear-weapon development programs (the "Manhattan Project").

Genetics and molecular mapping of genes for race-specific all-stage resistance and non-race-specific high-temperature adult-plant resistance to stripe rust in spring wheat cultivar Alpowa.

PubMed

Lin, F; Chen, X M

2007-05-01

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most widespread and destructive wheat diseases worldwide. Growing resistant cultivars is the preferred control of the disease. The spring wheat cultivar 'Alpowa' has both race-specific, all-stage resistance and non-race-specific, high-temperature adult-plant (HTAP) resistances to stripe rust. To identify genes for the stripe rust resistances, Alpowa was crossed with 'Avocet Susceptible' (AVS). Seedlings of the parents, and F(1), F(2) and F(3) progeny were tested with races PST-1 and PST-21 of P. striiformis f. sp. tritici under controlled greenhouse conditions. Alpowa has a single partially dominant gene, designated as YrAlp, conferring all-stage resistance. Resistance gene analog polymorphism (RGAP) and simple sequence repeat (SSR) techniques were used to identify molecular markers linked to YrAlp. A linkage group of five RGAP markers and two SSR markers was constructed for YrAlp using 136 F(3) lines. Amplification of a set of nulli-tetrasomic Chinese Spring lines with RGAP markers Xwgp47 and Xwgp48 and the two SSR markers indicated that YrAlp is located on the short arm of chromosome 1B. To map quantitative trait loci (QTLs) for the non-race-specific HTAP resistance, the parents and 136 F(3) lines were tested at two sites near Pullman and one site near Mount Vernon, Washington, under naturally infected conditions. A major HTAP QTL was consistently detected across environments and was located on chromosome 7BL. Because of its chromosomal location and the non-race-specific nature of the HTAP resistance, this gene is different from previously described genes for adult-plant resistance, and is therefore designated Yr39. The gene contributed to 64.2% of the total variation of relative area under disease progress curve (AUDPC) data and 59.1% of the total variation of infection type data recorded at the heading-flowering stages. Two RGAP markers, Xwgp36 and Xwgp45 with the highest R (2) values were closely linked to Yr39, should be useful for incorporation of the non-race-specific resistance gene into new cultivars and for combining Yr39 with other genes for durable and high-level resistance.

Ecological and Evolutionary Effects of Dispersal on Freshwater Zooplankton

ERIC Educational Resources Information Center

Allen, Michael R.

2009-01-01

A recent focus on contemporary evolution and the connections between communities has sought to more closely integrate ecology with evolutionary biology. Studies of coevolutionary dynamics, life history evolution, and rapid local adaptation demonstrate that ecological circumstances can dictate evolutionary trajectories. Thus, variation in species…

Gene-Culture Coevolutionary Games

ERIC Educational Resources Information Center

Blute, Marion

2006-01-01

Gene-culture interactions have largely been modelled employing population genetic-type models. Moreover, in the most notable application to date, the "interactive" modes have been one way rather than bidirectional. This paper suggests using game theoretic, fully interactive models. Employing the logic utilized in population ecology for coevolution…

Howling about Trophic Cascades

ERIC Educational Resources Information Center

Kowalewski, David

2012-01-01

Following evolutionary theory and an agriculture model, ecosystem research has stressed bottom-up dynamics, implying that top wild predators are epiphenomenal effects of more basic causes. As such, they are assumed expendable. A more modern co-evolutionary and wilderness approach--trophic cascades--instead suggests that top predators, whose…

The phylogenetic structure of plant-pollinator networks increases with habitat size and isolation.

PubMed

Aizen, Marcelo A; Gleiser, Gabriela; Sabatino, Malena; Gilarranz, Luis J; Bascompte, Jordi; Verdú, Miguel

2016-01-01

Similarity among species in traits related to ecological interactions is frequently associated with common ancestry. Thus, closely related species usually interact with ecologically similar partners, which can be reinforced by diverse co-evolutionary processes. The effect of habitat fragmentation on the phylogenetic signal in interspecific interactions and correspondence between plant and animal phylogenies is, however, unknown. Here, we address to what extent phylogenetic signal and co-phylogenetic congruence of plant-animal interactions depend on habitat size and isolation by analysing the phylogenetic structure of 12 pollination webs from isolated Pampean hills. Phylogenetic signal in interspecific interactions differed among webs, being stronger for flower-visiting insects than plants. Phylogenetic signal and overall co-phylogenetic congruence increased independently with hill size and isolation. We propose that habitat fragmentation would erode the phylogenetic structure of interaction webs. A decrease in phylogenetic signal and co-phylogenetic correspondence in plant-pollinator interactions could be associated with less reliable mutualism and erratic co-evolutionary change. © 2015 John Wiley & Sons Ltd/CNRS.

Public goods games on adaptive coevolutionary networks

NASA Astrophysics Data System (ADS)

Pichler, Elgar; Shapiro, Avi M.

2017-07-01

Productive societies feature high levels of cooperation and strong connections between individuals. Public Goods Games (PGGs) are frequently used to study the development of social connections and cooperative behavior in model societies. In such games, contributions to the public good are made only by cooperators, while all players, including defectors, reap public goods benefits, which are shares of the contributions amplified by a synergy factor. Classic results of game theory show that mutual defection, as opposed to cooperation, is the Nash Equilibrium of PGGs in well-mixed populations, where each player interacts with all others. In this paper, we explore the coevolutionary dynamics of a low information public goods game on a complex network in which players adapt to their environment in order to increase individual payoffs relative to past payoffs parameterized by greediness. Players adapt by changing their strategies, either to cooperate or to defect, and by altering their social connections. We find that even if players do not know other players' strategies and connectivity, cooperation can arise and persist despite large short-term fluctuations.

Public goods games on adaptive coevolutionary networks.

PubMed

Pichler, Elgar; Shapiro, Avi M

2017-07-01

Productive societies feature high levels of cooperation and strong connections between individuals. Public Goods Games (PGGs) are frequently used to study the development of social connections and cooperative behavior in model societies. In such games, contributions to the public good are made only by cooperators, while all players, including defectors, reap public goods benefits, which are shares of the contributions amplified by a synergy factor. Classic results of game theory show that mutual defection, as opposed to cooperation, is the Nash Equilibrium of PGGs in well-mixed populations, where each player interacts with all others. In this paper, we explore the coevolutionary dynamics of a low information public goods game on a complex network in which players adapt to their environment in order to increase individual payoffs relative to past payoffs parameterized by greediness. Players adapt by changing their strategies, either to cooperate or to defect, and by altering their social connections. We find that even if players do not know other players' strategies and connectivity, cooperation can arise and persist despite large short-term fluctuations.

A Multipopulation Coevolutionary Strategy for Multiobjective Immune Algorithm

PubMed Central

Shi, Jiao; Gong, Maoguo; Ma, Wenping; Jiao, Licheng

2014-01-01

How to maintain the population diversity is an important issue in designing a multiobjective evolutionary algorithm. This paper presents an enhanced nondominated neighbor-based immune algorithm in which a multipopulation coevolutionary strategy is introduced for improving the population diversity. In the proposed algorithm, subpopulations evolve independently; thus the unique characteristics of each subpopulation can be effectively maintained, and the diversity of the entire population is effectively increased. Besides, the dynamic information of multiple subpopulations is obtained with the help of the designed cooperation operator which reflects a mutually beneficial relationship among subpopulations. Subpopulations gain the opportunity to exchange information, thereby expanding the search range of the entire population. Subpopulations make use of the reference experience from each other, thereby improving the efficiency of evolutionary search. Compared with several state-of-the-art multiobjective evolutionary algorithms on well-known and frequently used multiobjective and many-objective problems, the proposed algorithm achieves comparable results in terms of convergence, diversity metrics, and running time on most test problems. PMID:24672330

Female burying beetles benefit from male desertion: sexual conflict and counter-adaptation over parental investment.

PubMed

Boncoraglio, Giuseppe; Kilner, Rebecca M

2012-01-01

Sexual conflict drives the coevolution of sexually antagonistic traits, such that an adaptation in one sex selects an opposing coevolutionary response from the other. Although many adaptations and counteradaptations have been identified in sexual conflict over mating interactions, few are known for sexual conflict over parental investment. Here we investigate a possible coevolutionary sequence triggered by mate desertion in the burying beetle Nicrophorus vespilloides, where males commonly leave before their offspring reach independence. Rather than suffer fitness costs as a consequence, our data suggest that females rely on the male's absence to recoup some of the costs of larval care, presumably because they are then free to feed themselves on the carcass employed for breeding. Consequently, forcing males to stay until the larvae disperse reduces components of female fitness to a greater extent than caring for young singlehandedly. Therefore we suggest that females may have co-evolved to anticipate desertion by their partners so that they now benefit from the male's absence.

Female Burying Beetles Benefit from Male Desertion: Sexual Conflict and Counter-Adaptation over Parental Investment

PubMed Central

Boncoraglio, Giuseppe; Kilner, Rebecca M.

2012-01-01

Sexual conflict drives the coevolution of sexually antagonistic traits, such that an adaptation in one sex selects an opposing coevolutionary response from the other. Although many adaptations and counteradaptations have been identified in sexual conflict over mating interactions, few are known for sexual conflict over parental investment. Here we investigate a possible coevolutionary sequence triggered by mate desertion in the burying beetle Nicrophorus vespilloides, where males commonly leave before their offspring reach independence. Rather than suffer fitness costs as a consequence, our data suggest that females rely on the male's absence to recoup some of the costs of larval care, presumably because they are then free to feed themselves on the carcass employed for breeding. Consequently, forcing males to stay until the larvae disperse reduces components of female fitness to a greater extent than caring for young singlehandedly. Therefore we suggest that females may have co-evolved to anticipate desertion by their partners so that they now benefit from the male's absence. PMID:22355390

Na+/K+-ATPase resistance and cardenolide sequestration: basal adaptations to host plant toxins in the milkweed bugs (Hemiptera: Lygaeidae: Lygaeinae)

PubMed Central

Bramer, Christiane; Dobler, Susanne; Deckert, Jürgen; Stemmer, Michael; Petschenka, Georg

2015-01-01

Despite sequestration of toxins being a common coevolutionary response to plant defence in phytophagous insects, the macroevolution of the traits involved is largely unaddressed. Using a phylogenetic approach comprising species from four continents, we analysed the ability to sequester toxic cardenolides in the hemipteran subfamily Lygaeinae, which is widely associated with cardenolide-producing Apocynaceae. In addition, we analysed cardenolide resistance of their Na+/K+-ATPases, the molecular target of cardenolides. Our data indicate that cardenolide sequestration and cardenolide-resistant Na+/K+-ATPase are basal adaptations in the Lygaeinae. In two species that shifted to non-apocynaceous hosts, the ability to sequester was secondarily reduced, yet Na+/K+-ATPase resistance was maintained. We suggest that both traits evolved together and represent major coevolutionary adaptations responsible for the evolutionary success of lygaeine bugs. Moreover, specialization on cardenolides was not an evolutionary dead end, but enabled this insect lineage to host shift to cardenolide-producing plants from distantly related families. PMID:25808891

The bacterial parasite Pasteuria ramosa is not killed if it fails to infect: implications for coevolution.

PubMed

King, Kayla C; Auld, Stuart K J R; Wilson, Philip J; James, Janna; Little, Tom J

2013-02-01

Strong selection on parasites, as well as on hosts, is crucial for fueling coevolutionary dynamics. Selection will be especially strong if parasites that encounter resistant hosts are destroyed and diluted from the local environment. We tested whether spores of the bacterial parasite Pasteuria ramosa were passed through the gut (the route of infection) of their host, Daphnia magna, and whether passaged spores remained viable for a "second chance" at infecting a new host. In particular, we tested if this viability (estimated via infectivity) depended on host genotype, whether or not the genotype was susceptible, and on initial parasite dose. Our results show that Pasteuria spores generally remain viable after passage through both susceptible and resistant Daphnia. Furthermore, these spores remained infectious even after being frozen for several weeks. If parasites can get a second chance at infecting hosts in the wild, selection for infection success in the first instance will be reduced. This could also weaken reciprocal selection on hosts and slow the coevolutionary process.

Mathematical model and metaheuristics for simultaneous balancing and sequencing of a robotic mixed-model assembly line

NASA Astrophysics Data System (ADS)

Li, Zixiang; Janardhanan, Mukund Nilakantan; Tang, Qiuhua; Nielsen, Peter

2018-05-01

This article presents the first method to simultaneously balance and sequence robotic mixed-model assembly lines (RMALB/S), which involves three sub-problems: task assignment, model sequencing and robot allocation. A new mixed-integer programming model is developed to minimize makespan and, using CPLEX solver, small-size problems are solved for optimality. Two metaheuristics, the restarted simulated annealing algorithm and co-evolutionary algorithm, are developed and improved to address this NP-hard problem. The restarted simulated annealing method replaces the current temperature with a new temperature to restart the search process. The co-evolutionary method uses a restart mechanism to generate a new population by modifying several vectors simultaneously. The proposed algorithms are tested on a set of benchmark problems and compared with five other high-performing metaheuristics. The proposed algorithms outperform their original editions and the benchmarked methods. The proposed algorithms are able to solve the balancing and sequencing problem of a robotic mixed-model assembly line effectively and efficiently.

An analysis of parameter sensitivities of preference-inspired co-evolutionary algorithms

NASA Astrophysics Data System (ADS)

Wang, Rui; Mansor, Maszatul M.; Purshouse, Robin C.; Fleming, Peter J.

2015-10-01

Many-objective optimisation problems remain challenging for many state-of-the-art multi-objective evolutionary algorithms. Preference-inspired co-evolutionary algorithms (PICEAs) which co-evolve the usual population of candidate solutions with a family of decision-maker preferences during the search have been demonstrated to be effective on such problems. However, it is unknown whether PICEAs are robust with respect to the parameter settings. This study aims to address this question. First, a global sensitivity analysis method - the Sobol' variance decomposition method - is employed to determine the relative importance of the parameters controlling the performance of PICEAs. Experimental results show that the performance of PICEAs is controlled for the most part by the number of function evaluations. Next, we investigate the effect of key parameters identified from the Sobol' test and the genetic operators employed in PICEAs. Experimental results show improved performance of the PICEAs as more preferences are co-evolved. Additionally, some suggestions for genetic operator settings are provided for non-expert users.

Cluster Randomized Trial of a Toolkit and Early Vaccine Delivery to Improve Childhood Influenza Vaccination Rates in Primary Care

PubMed Central

Zimmerman, Richard K.; Nowalk, Mary Patricia; Lin, Chyongchiou Jeng; Hannibal, Kristin; Moehling, Krissy K.; Huang, Hsin-Hui; Matambanadzo, Annamore; Troy, Judith; Allred, Norma J.; Gallik, Greg; Reis, Evelyn C.

2014-01-01

Purpose To increase childhood influenza vaccination rates using a toolkit and early vaccine delivery in a randomized cluster trial. Methods Twenty primary care practices treating children (range for n=536-8,183) were randomly assigned to Intervention and Control arms to test the effectiveness of an evidence-based practice improvement toolkit (4 Pillars Toolkit) and early vaccine supplies for use among disadvantaged children on influenza vaccination rates among children 6 months-18 years. Follow-up staff meetings and surveys were used to assess use and acceptability of the intervention strategies in the Intervention arm. Rates for the 2010-2011 and 2011-2012 influenza seasons were compared. Two-level generalized linear mixed modeling was used to evaluate outcomes. Results Overall increases in influenza vaccination rates were significantly greater in the Intervention arm (7.9 percentage points) compared with the Control arm (4.4 percentage points; P<0.034). These rate changes represent 4522 additional doses in the Intervention arm vs. 1,390 additional doses in the Control arm. This effect of the intervention was observed despite the fact that rates increased significantly in both arms - 8/10 Intervention (P<0.001) and 7/10 Control sites (P-values 0.04 to <0.001). Rates in two Intervention sites with pre-intervention vaccination rates >58% did not significantly increase. In regression analyses, a child's likelihood of being vaccinated was significantly higher with: younger age, white race (Odds ratio [OR]=1.29; 95% confidence interval [CI]=1.23-1.34), having commercial insurance (OR=1.30; 95%CI=1.25-1.35), higher pre-intervention practice vaccination rate (OR=1.25; 95%CI=1.16-1.34), and being in the Intervention arm (OR=1.23; 95%CI=1.01-1.50). Early delivery of influenza vaccine was rated by Intervention practices as an effective strategy for raising rates. Conclusions Implementation of a multi-strategy toolkit and early vaccine supplies can significantly improve influenza vaccination rates among children in primary care practices but the effect may be less pronounced in practices with moderate to high existing vaccination rates. PMID:24793941

The effects of Robertsonian fusions on chiasma frequency and distribution in the house mouse (Mus musculus domesticus) from a hybrid zone in northern Scotland.

PubMed

Bidau, C J; Giménez, M D; Palmer, C L; Searle, J B

2001-09-01

Chiasma frequency and distribution were studied in male Mus musculus domesticus from the John O'Groats-standard chromosomal hybrid zone in northern Scotland. Individuals of the John O'Groats race (2n=32; homozygous for the Robertsonian fusions 4.10, 6.13, 9.12 and 11.14) and the standard race (2n=40, all telocentric), and hybrids with various karyotypes, were examined. Chiasma frequency was significantly negatively correlated with the number of Robertsonian configurations in the meiotic cell. The decrease of chiasma frequency can be attributed to intrachromosomal effects that reduce the number of chiasmata in Robertsonian bivalents (formed in homozygotes for Robertsonian fusions) and trivalents (formed in heterozygotes). However, the reduction is more pronounced in Robertsonian bivalents and is related to a shift of chiasmata to the distal ends of the chromosome arms. A different type of repatterning occurs in trivalents where there is a significant increase in proximal and interstitial chiasmata.

Nonlinear Dynamics of Complex Coevolutionary Systems in Historical Times

NASA Astrophysics Data System (ADS)

Perdigão, Rui A. P.

2016-04-01

A new theoretical paradigm for statistical-dynamical modeling of complex coevolutionary systems is introduced, with the aim to provide historical geoscientists with a practical tool to analyse historical data and its underlying phenomenology. Historical data is assumed to represent the history of dynamical processes of physical and socio-economic nature. If processes and their governing laws are well understood, they are often treated with traditional dynamical equations: deterministic approach. If the governing laws are unknown or impracticable, the process is often treated as if being random (even if it is not): statistical approach. Although single eventful details - such as the exact spatiotemporal structure of a particular hydro-meteorological incident - may often be elusive to a detailed analysis, the overall dynamics exhibit group properties summarized by a simple set of categories or dynamical regimes at multiple scales - from local short-lived convection patterns to large-scale hydro-climatic regimes. The overwhelming microscale complexity is thus conveniently wrapped into a manageable group entity, such as a statistical distribution. In a stationary setting whereby the distribution is assumed to be invariant, alternating regimes are approachable as dynamical intermittence. For instance, in the context of bimodal climatic oscillations such as NAO and ENSO, each mode corresponds to a dynamical regime or phase. However, given external forcings or longer-term internal variability and multiscale coevolution, the structural properties of the system may change. These changes in the dynamical structure bring about a new distribution and associated regimes. The modes of yesteryear may no longer exist as such in the new structural order of the system. In this context, aside from regime intermittence, the system exhibits structural regime change. New oscillations may emerge whilst others fade into the annals of history, e.g. particular climate fluctuations during the Little Ice Age. Traditional theories of stochastic processes and dynamical systems are grounded on the existence of so-called dynamical invariants; properties that remain unchanged as the dynamics unfold, assuming structural invariance and ergodicity of the underlying system. However, such theories are no longer optimal when trying to understand and model long-term historical records of coevolutionary systems. A new paradigm is thus needed. Therefore, we introduce a new class of dynamical systems that reinvent themselves as the dynamics unfold. Rather than only changing variables and parameters under a rigid framework, the governing laws are malleable themselves. The novel formulation captures and explains the coevolutionary dynamics of multiscale hydroclimatic systems, bringing along a physically sound understanding of their regimes, transitions and extremes over a long-term history.

Affinity maturation in an HIV broadly neutralizing B-cell lineage through reorientation of variable domains.

PubMed

Fera, Daniela; Schmidt, Aaron G; Haynes, Barton F; Gao, Feng; Liao, Hua-Xin; Kepler, Thomas B; Harrison, Stephen C

2014-07-15

Rapidly evolving pathogens, such as human immunodeficiency and influenza viruses, escape immune defenses provided by most vaccine-induced antibodies. Proposed strategies to elicit broadly neutralizing antibodies require a deeper understanding of antibody affinity maturation and evolution of the immune response to vaccination or infection. In HIV-infected individuals, viruses and B cells evolve together, creating a virus-antibody "arms race." Analysis of samples from an individual designated CH505 has illustrated the interplay between an antibody lineage, CH103, and autologous viruses at various time points. The CH103 antibodies, relatively broad in their neutralization spectrum, interact with the CD4 binding site of gp120, with a contact dominated by CDRH3. We show by analyzing structures of progenitor and intermediate antibodies and by correlating them with measurements of binding to various gp120s that there was a shift in the relative orientation of the light- and heavy-chain variable domains during evolution of the CH103 lineage. We further show that mutations leading to this conformational shift probably occurred in response to insertions in variable loop 5 (V5) of the HIV envelope. The shift displaced the tips of the light chain away from contact with V5, making room for the inserted residues, which had allowed escape from neutralization by the progenitor antibody. These results, which document the selective mechanism underlying this example of a virus-antibody arms race, illustrate the functional significance of affinity maturation by mutation outside the complementarity determining region surface of the antibody molecule.

The physiology of mountain biking.

PubMed

Impellizzeri, Franco M; Marcora, Samuele M

2007-01-01

Mountain biking is a popular outdoor recreational activity and an Olympic sport. Cross-country circuit races have a winning time of approximately equal 120 minutes and are performed at an average heart rate close to 90% of the maximum, corresponding to 84% of maximum oxygen uptake (VO2max). More than 80% of race time is spent above the lactate threshold. This very high exercise intensity is related to the fast starting phase of the race; the several climbs, forcing off-road cyclists to expend most of their effort going against gravity; greater rolling resistance; and the isometric contractions of arm and leg muscles necessary for bike handling and stabilisation. Because of the high power output (up to 500W) required during steep climbing and at the start of the race, anaerobic energy metabolism is also likely to be a factor of off-road cycling and deserves further investigation. Mountain bikers' physiological characteristics indicate that aerobic power (VO2max >70 mL/kg/min) and the ability to sustain high work rates for prolonged periods of time are prerequisites for competing at a high level in off-road cycling events. The anthropometric characteristics of mountain bikers are similar to climbers and all-terrain road cyclists. Various parameters of aerobic fitness are correlated to cross-country performance, suggesting that these tests are valid for the physiological assessment of competitive mountain bikers, especially when normalised to body mass. Factors other than aerobic power and capacity might influence off-road cycling performance and require further investigation. These include off-road cycling economy, anaerobic power and capacity, technical ability and pre-exercise nutritional strategies.

A novel Robertsonian translocation event leads to transfer of a stem rust resistance gene (Sr52) effective against race Ug99 from Dasypyrum villosum into bread wheat.

PubMed

Qi, L L; Pumphrey, M O; Friebe, Bernd; Zhang, P; Qian, C; Bowden, R L; Rouse, M N; Jin, Y; Gill, B S

2011-06-01

Stem rust (Puccinia graminis f. sp. tritici Eriks. & E. Henn.) (the causal agent of wheat stem rust) race Ug99 (also designated TTKSK) and its derivatives have defeated several important stem rust resistance genes widely used in wheat (Triticum aestivum L.) production, rendering much of the worldwide wheat acreage susceptible. In order to identify new resistance sources, a large collection of wheat relatives and genetic stocks maintained at the Wheat Genetic and Genomic Resources Center was screened. The results revealed that most accessions of the diploid relative Dasypyrum villosum (L.) Candargy were highly resistant. The screening of a set of wheat-D. villosum chromosome addition lines revealed that the wheat-D. villosum disomic addition line DA6V#3 was moderately resistant to race Ug99. The objective of the present study was to produce and characterize compensating wheat-D. villosum whole arm Robertsonian translocations (RobTs) involving chromosomes 6D of wheat and 6V#3 of D. villosum through the mechanism of centric breakage-fusion. Seven 6V#3-specific EST-STS markers were developed for screening F(2) progeny derived from plants double-monosomic for chromosomes 6D and 6V#3. Surprisingly, although 6D was the target chromosome, all recovered RobTs involved chromosome 6A implying a novel mechanism for the origin of RobTs. Homozygous translocations (T6AS·6V#3L and T6AL·6V#3S) with good plant vigor and full fertility were selected from F(3) families. A stem rust resistance gene was mapped to the long arm 6V#3L in T6AS·6V#3L and was designated as Sr52. Sr52 is temperature-sensitive and is most effective at 16°C, partially effective at 24°C, and ineffective at 28°C. The T6AS·6V#3L stock is a new source of resistance to Ug99, is cytogenetically stable, and may be useful in wheat improvement.

Host responses to historical climate change shape parasite communities in North America’s intermountain west

USDA-ARS?s Scientific Manuscript database

Host-parasite co-speciation, in which parasite divergence occurs in response to host divergence, is commonly proposed as a driver of parasite diversification, yet few empirical examples of strict co-speciation exist. Host-parasite co-evolutionary histories commonly reflect complex mosaics of co-spe...

Reduction in fecundity and shifts in cellular processes by a native virus on an invasive insect

USDA-ARS?s Scientific Manuscript database

Pathogens and their vectors have co-evolutionary histories that are intricately intertwined with their ecologies, environments and genetic interactions. The majority of non-persistently transmitted plant viruses are transmitted by aphid species. One important aphid vector in soybean-growing regions ...

Toward a Pedagogy of Ecological Responsibility: Learning to Reinhabit the Earth.

ERIC Educational Resources Information Center

Mische, Patricia M.

1992-01-01

Environmental damage harms the rights of future generations. Peace and disarmament are environmental issues necessitating rethinking of national security. Coevolutionary ethics involve balancing the individual with the common good and establishing equilibrium among the biosphere, technosphere, sociosphere, and the sphere of mind and spirit. (SK)

Efficacy of a Chronic Care-Based Intervention on Secondary Stroke Prevention Among Vulnerable Stroke Survivors: A Randomized Controlled Trial.

PubMed

Cheng, Eric M; Cunningham, William E; Towfighi, Amytis; Sanossian, Nerses; Bryg, Robert J; Anderson, Thomas L; Barry, Frances; Douglas, Susan M; Hudson, Lillie; Ayala-Rivera, Monica; Guterman, Jeffrey J; Gross-Schulman, Sandra; Beanes, Sylvia; Jones, Andrea S; Liu, Honghu; Vickrey, Barbara G

2018-01-01

Disparities of care among stroke survivors are well documented. Effective interventions to improve recurrent stroke preventative care in vulnerable populations are lacking. In a randomized controlled trial, we tested the efficacy of components of a chronic care model-based intervention versus usual care among 404 subjects having an ischemic stroke or transient ischemic attack within 90 days of enrollment and receiving care within the Los Angeles public healthcare system. Subjects had baseline systolic blood pressure (SBP) ≥120 mm Hg. The intervention included a nurse practitioner/physician assistant care manager, group clinics, self-management support, report cards, decision support, and ongoing care coordination. Outcomes were collected at 3, 8, and 12 months, analyzed as intention-to-treat, and used repeated-measures mixed-effects models. Change in SBP was the primary outcome. Low-density lipoprotein reduction, antithrombotic medication use, smoking cessation, and physical activity were secondary outcomes. Average age was 57 years; 18% were of black race; 69% were of Hispanic ethnicity. Mean baseline SBP was 150 mm Hg in both arms. SBP decreased to 17 mm Hg in the intervention arm and 14 mm Hg in the usual care arm; the between-arm difference was not significant (-3.6 mm Hg; 95% confidence interval, -9.2 to 2.2). Among secondary outcomes, the only significant difference was that persons in the intervention arm were more likely to lower their low-density lipoprotein <100 md/dL (2.0 odds ratio; 95% confidence interval, 1.1-3.5). This intervention did not improve SBP control beyond that attained in usual care among vulnerable stroke survivors. A community-centered component could strengthen the intervention impact. URL: https://clinicaltrials.gov. Unique identifier: NCT00861081. © 2017 American Heart Association, Inc.

Aerobic power and peak power of elite America's Cup sailors.

PubMed

Neville, Vernon; Pain, Matthew T G; Folland, Jonathan P

2009-05-01

Big-boat yacht racing is one of the only able bodied sporting activities where standing arm-cranking ('grinding') is the primary physical activity. However, the physiological capabilities of elite sailors for standing arm-cranking have been largely unreported. The purpose of the study was to assess aerobic parameters, VO(2peak) and onset of blood lactate (OBLA), and anaerobic performance, torque-crank velocity and power-crank velocity relationships and therefore peak power (P (max)) and optimum crank-velocity (omega(opt)), of America's Cup sailors during standing arm-cranking. Thirty-three elite professional sailors performed a step test to exhaustion, and a subset of ten grinders performed maximal 7 s isokinetic sprints at different crank velocities, using a standing arm-crank ergometer. VO(2peak) was 4.7 +/- 0.5 L/min (range 3.6-5.5 L/min) at a power output of 332 +/- 44 W (range 235-425 W). OBLA occurred at a power output of 202 +/- 31 W (61% of W(max)) and VO(2) of 3.3 +/- 0.4 L/min (71% of VO(2peak)). The torque-crank velocity relationship was linear for all participants (r = 0.9 +/- 0.1). P (max) was 1,420 +/- 37 W (range 1,192-1,617 W), and omega(opt) was 125 +/- 6 rpm. These data are among the highest upper-body anaerobic and aerobic power values reported. The unique nature of these athletes, with their high fat-free mass and specific selection and training for standing arm cranking, likely accounts for the high values. The influence of crank velocity on peak power implies that power production during on-board 'grinding' may be optimised through the use of appropriate gear-ratios and the development of efficient gear change mechanisms.

The Anti-Satellite (ASAT) Weapon Problem And Congress

NASA Astrophysics Data System (ADS)

Treglio, James R.

1984-08-01

An amendment to the 1984 Defense Authorization Act prevents testing against objects in space of an American F-15 launched anti-satellite weapon until the President certifies that the testing is necessary to prevent harm to the national security, and that he is willing to negotiate an ASAT treaty with the Soviet Union. This extraordinary action by the Congress was taken because many members of Congress feared that the weapon was being developed without due consideration for its impact on arms control, that temporary technical superiority was being given greater importance than the long-term security of the nation. This increased Congressional scrutiny could have an impact on future weapons development programs. "Now a crucial moment is really coming: Either the interested parties will sit down at the negotiating table without delay to begin drawing up a treaty prohibiting the placement in space of weapons of any kind, or the arms race will spill over into space." YURI ANDROPOV, April 28, 1983, in response to petition from American Scientists.

Scientific impacts on nuclear strategic policy: Dangers and opportunities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keeny S.M. Jr.

1988-12-15

Nuclear weapons have revolutionized warfare, making a mutual capability for assured destruction a fact of life and mutual assured deterrence the underlying nuclear strategy of the superpowers. The program to find a technical solution to the threat of nuclear weapons by creating an impervious defense is fatally flawed by failure to consider responses available to a sophisticated adversary at much lower cost. Responses could involve: exploiting vulnerabilities; increased firepower; technical innovation; and circumvention. Efforts to achieve strategic defense would in fact increase risk of nuclear war by stimulating the nuclear arms race since history demonstrates neither side will allow itsmore » deterrent force to be seriously degraded. Defenses would increase instability in times of a crisis. Science has also reduced the risk of nuclear war by making possible improved control and safety of nuclear forces and predictability of US/Soviet relations, verifiability of arms control agreements, and survivable strategic systems. Science can be a tool for good or evil; mankind must be its masters not its slaves.« less

Scientific impacts on nuclear strategic policy: Dangers and opportunities

NASA Astrophysics Data System (ADS)

Keeny, Spurgeon M.

1988-12-01

Nuclear weapons have revolutionized warfare, making a mutual capability for assured destruction a fact of life and mutual assured deterrence the underlying nuclear strategy of the superpowers. The program to find a technical solution to the threat of nuclear weapons by creating an impervious defense is fatally flawed by failure to consider responses available to a sophisticated adversary at much lower cost. Responses could involve: exploiting vulnerabilities; increased firepower; technical innovation; and circumvention. Efforts to achieve strategic defense would in fact increase risk of nuclear war by stimulating the nuclear arms race since history demonstrates neither side will allow its deterrent force to be seriously degraded. Defenses would increase instability in times of a crisis. Science has also reduced the risk of nuclear war by making possible improved control and safety of nuclear forces and predictability of US/Soviet relations, verifiability of arms control agreements, and survivable strategic systems. Science can be a tool for good or evil; mankind must be its masters not its slaves.

Rocketry, film and fiction: the road to Sputnik

NASA Astrophysics Data System (ADS)

Brake, Mark; Hook, Neil

2007-07-01

The launch of Sputnik 1 in 1957 was fuelled by science fiction as well as science fact. The field of early rocketry included the work of Russians Nikolai Rynin and Konstantin Tsiolkovsky, American Robert Goddard, and German engineers Herman Oberth and Wernher Von Braun. All were directly inspired and influenced by early science fiction that heralded a space age decades ahead of time. The work of these pioneers led directly to the development of the technology needed to boost Sputnik skyward. After the launch of Sputnik, the context of the nuclear arms race opened the floodgates for a new wave of apocalyptic fiction.

KSC-08pd0715

NASA Image and Video Library

2008-03-11

KENNEDY SPACE CENTER, FLA. --Racing into the night sky atop columns of fire, space shuttle Endeavour on mission STS-123 shows blue cones of light beneath its engines. The shock or mach diamonds are a formation of shock waves in the exhaust plume of an aerospace propulsion system. Liftoff was on time at 2:28 a.m. EDT. The crew will make a record-breaking 16-day mission to the International Space Station and deliver the first section of the Japan Aerospace Exploration Agency's Kibo laboratory and the Canadian Space Agency's two-armed robotic system, Dextre. Photo credit: NASA/Jerry Cannon, Rusty Backer

Autophagy and bacterial infection: an evolving arms race.

PubMed

Choy, Augustine; Roy, Craig R

2013-09-01

Autophagy is an important membrane transport pathway that is conserved among eukaryotic cells. Although first described as an intracellular catabolic pathway used to break down self-components, autophagy has been found to play an important role in the elimination of intracellular pathogens. A variety of host mechanisms exist for recognizing and targeting intracellular bacteria to autophagosomes. Several intracellular bacteria have evolved ways to manipulate, inhibit, or avoid autophagy in order to survive in the cell. Thus, the autophagy pathway can be viewed as an evolutionarily conserved host response to infection. Copyright © 2013 Elsevier Ltd. All rights reserved.

History of Nuclear Weapons Design and Production

NASA Astrophysics Data System (ADS)

Oelrich, Ivan

2007-04-01

The nuclear build-up of the United States and the Soviet Union during the Cold War is often portrayed as an arms race. Some part was indeed a bilateral competition, but much was the result of automatic application of technical advances as they became available, without careful consideration of strategic implications. Thus, the history of nuclear weapon design is partly designers responding to stated military needs and partly the world responding to constant innovations in nuclear capability. Today, plans for a new nuclear warhead are motivated primarily by the desire to maintain a nuclear design and production capability for the foreseeable future.

Specialty-service lines: salvos in the new medical arms race.

PubMed

Berenson, Robert A; Bodenheimer, Thomas; Pham, Hoangmai H

2006-01-01

Hospitals and physicians are developing and marketing discrete and profitable specialty-service lines. Although closely affiliated specialist physicians are central to hospitals' service-line products, other physicians compete directly with hospitals via physician-owned specialty facilities. Specialty-service lines may be provided in a variety of settings, both inside and outside traditional hospital walls. Thus far, the escalating battle between hospitals and physicians for control over specialty services has not affected hospital profitability. However, as the scope of care that can be safely performed in the outpatient arena expands, physician competition for control over specialty services may threaten hospitals' financial health.

Military Base Realignments and Closures: Impact of Terminating, Relocating, or Outsourcing the Services of the Armed Forces Institute of Pathology

DTIC Science & Technology

2007-11-01

sexes , all races/ethnicities, all ages, as well... Tenn . 2 Ala. 88 Fla. 820 Ga. 1,220 S.C. 291 N.C. 1,371 Va. 1,476 Ohio 467 N.H. 0 Mass. 6 R.I. 0Mich. 1 Calif. 1,974 Wash. 671 Wis. 13 N.Y. 1,614 Maine...809 Tenn . 205 Ala. 102 Fla. 1,109 Ga. 376 S.C. 396 N.C. 769 Va. 331 Ohio 731 N.H. 40 Mass. 97 R.I. 38Mich. 189 Calif. 801 Wash. 59 Wis. 68 N.Y.

A comparison of web-based versus print-based decision AIDS for prostate cancer screening: participants' evaluation and utilization.

PubMed

Tomko, Catherine; Davis, Kimberly M; Luta, George; Krist, Alexander H; Woolf, Steven H; Taylor, Kathryn L

2015-01-01

Patient decision aids facilitate informed decision making for medical tests and procedures that have uncertain benefits. To describe participants' evaluation and utilization of print-based and web-based prostate cancer screening decision aids that were found to improve decisional outcomes in a prior randomized controlled trial. Men completed brief telephone interviews at baseline, one month, and 13 months post-randomization. Participants were primary care patients, 45-70 years old, who received the print-based (N = 628) or web-based decision aid (N = 625) and completed the follow-up assessments. We assessed men's baseline preference for web-based or print-based materials, time spent using the decision aids, comprehension of the overall message, and ratings of the content. Decision aid use was self-reported by 64.3 % (web) and 81.8 % (print) of participants. Significant predictors of decision aid use were race (white vs. non-white, OR = 2.43, 95 % CI: 1.77, 3.35), higher education (OR = 1.68, 95 % CI: 1.06, 2.70) and trial arm (print vs. web, OR = 2.78, 95 % CI: 2.03, 3.83). Multivariable analyses indicated that web-arm participants were more likely to use the website when they preferred web-based materials (OR: 1.91, CI: 1.17, 3.12), whereas use of the print materials was not significantly impacted by a preference for print-based materials (OR: 0.69, CI: 0.38, 1.25). Comprehension of the decision aid message (i.e., screening is an individual decision) did not significantly differ between arms in adjusted analyses (print: 61.9 % and web: 68.2 %, p = 0.42). Decision aid use was independently influenced by race, education, and the decision aid medium, findings consistent with the 'digital divide.' These results suggest that when it is not possible to provide this age cohort with their preferred decision aid medium, print materials will be more highly used than web-based materials. Although there are many advantages to web-based decision aids, providing an option for print-based decision aids should be considered.

Individual Patient Data Analysis of Randomized Clinical Trials: Impact of Black Race on Castration-resistant Prostate Cancer Outcomes.

PubMed

Spratt, Daniel E; Chen, Yu-Wei; Mahal, Brandon A; Osborne, Joseph R; Zhao, Shuang G; Morgan, Todd M; Palapattu, Ganesh; Feng, Felix Y; Nguyen, Paul L

2016-12-01

Population data suggest that black men have a higher risk of dying from prostate cancer (PCa) than other racial ethnicities. To examine the impact of black race on progression-free survival (PFS) and overall survival (OS) among men with metastatic castration-resistant PCa (mCRPC) enrolled in randomized controlled trials (RCTs). A pooled analysis was performed on individual patient data from five modern PCa RCTs available from Project Data Sphere. Adjusted hazard ratios (HRs) were calculated to compare black and white race regarding PFS and OS. Subgroup analyses of mCRPC trials were performed based on the control arm treatments (mitoxantrone or docetaxel). Relevant covariates were used for adjustment in all analyses. A total of 1613 patients were included; 77 were black (4.7%). No significant differences between black and white men's baseline characteristics were noted regarding age, performance status, or pretreatment prostate-specific antigen. The pooled HRs for black race for OS and PFS were 1.01 (95% confidence interval [CI], 0.73-1.35) and 1.29 (95% CI, 0.95-1.76), respectively. The median OS for black compared with white men was 254 versus 238 d (p=0.92), respectively, with mitoxantrone and 581 versus 546 d (p=0.53), respectively, with docetaxel. The primary limitation was the relatively small number of black men enrolled in mCRPC clinical trials. In the context of RCTs, in which patients receive generally uniform treatment, a significant difference in OS for black men could not be detected in mCRPC. Black men continue to be dramatically underrepresented in RCTs, and efforts are needed to increase minority accrual to these trials. We looked at the outcomes of men treated in randomized controlled trials to determine the impact of black race on survival. We found that in the context of modern clinical trials, there does not appear to be a significant difference in survival between black and white races; however, a trend for greater progression in black men was noted. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Relationship between Race and the Effect of Fluids on Long-term Mortality after Acute Respiratory Distress Syndrome. Secondary Analysis of the National Heart, Lung, and Blood Institute Fluid and Catheter Treatment Trial.

PubMed

Jolley, Sarah E; Hough, Catherine L; Clermont, Gilles; Hayden, Douglas; Hou, Suqin; Schoenfeld, David; Smith, Nicholas L; Thompson, Boyd Taylor; Bernard, Gordon R; Angus, Derek C

2017-09-01

Short-term follow-up in the Fluid and Catheter Treatment Trial (FACTT) suggested differential mortality by race with conservative fluid management, but no significant interaction. In a post hoc analysis of FACTT including 1-year follow-up, we sought to estimate long-term mortality by race and test for an interaction between fluids and race. We performed a post hoc analysis of FACTT and the Economic Analysis of Pulmonary Artery Catheters (EAPAC) study (which included 655 of the 1,000 FACTT patients with near-complete 1-year follow up). We fit a multistate Markov model to estimate 1-year mortality for all non-Hispanic black and white randomized FACTT subjects. The model estimated the distribution of time from randomization to hospital discharge or hospital death (available on all patients) and estimated the distribution of time from hospital discharge to death using data on patients after hospital discharge for patients in EAPAC. The 1-year mortality was found by combining these estimates. Non-Hispanic black (n = 217, 25%) or white identified subjects (n = 641, 75%) were included. There was a significant interaction between race and fluid treatment (P = 0.012). One-year mortality was lower for black subjects assigned to conservative fluids (38 vs. 54%; mean mortality difference, 16%; 95% confidence interval, 2-30%; P = 0.027 between conservative and liberal). Conversely, 1-year mortality for white subjects was 35% versus 30% for conservative versus liberal arms (mean mortality difference, -4.8%; 95% confidence interval, -13% to 3%; P = 0.23). In our cohort, conservative fluid management may have improved 1-year mortality for non-Hispanic black patients with ARDS. However, we found no long-term benefit of conservative fluid management in white subjects.

Routine versus aggressive upstream rhythm control for prevention of early atrial fibrillation in heart failure: background, aims and design of the RACE 3 study.

PubMed

Alings, M; Smit, M D; Moes, M L; Crijns, H J G M; Tijssen, J G P; Brügemann, J; Hillege, H L; Lane, D A; Lip, G Y H; Smeets, J R L M; Tieleman, R G; Tukkie, R; Willems, F F; Vermond, R A; Van Veldhuisen, D J; Van Gelder, I C

2013-07-01

Rhythm control for atrial fibrillation (AF) is cumbersome because of its progressive nature caused by structural remodelling. Upstream therapy refers to therapeutic interventions aiming to modify the atrial substrate, leading to prevention of AF. The Routine versus Aggressive upstream rhythm Control for prevention of Early AF in heart failure (RACE 3) study hypothesises that aggressive upstream rhythm control increases persistence of sinus rhythm compared with conventional rhythm control in patients with early AF and mild-to-moderate early systolic or diastolic heart failure undergoing electrical cardioversion. RACE 3 is a prospective, randomised, open, multinational, multicenter trial. Upstream rhythm control consists of angiotensin converting enzyme inhibitors and/or angiotensin receptor blockers, mineralocorticoid receptor antagonists, statins, cardiac rehabilitation therapy, and intensive counselling on dietary restrictions, exercise maintenance, and drug adherence. Conventional rhythm control consists of routine rhythm control therapy without cardiac rehabilitation therapy and intensive counselling. In both arms, every effort is made to keep patients in the rhythm control strategy, and ion channel antiarrhythmic drugs or pulmonary vein ablation may be instituted if AF relapses. Total inclusion will be 250 patients. If upstream therapy proves to be effective in improving maintenance of sinus rhythm, it could become a new approach to rhythm control supporting conventional pharmacological and non-pharmacological rhythm control.

Inheritance and Bulked Segregant Analysis of Leaf Rust and Stem Rust Resistance in Durum Wheat Genotypes.

PubMed

Aoun, Meriem; Kolmer, James A; Rouse, Matthew N; Chao, Shiaoman; Bulbula, Worku Denbel; Elias, Elias M; Acevedo, Maricelis

2017-12-01

Leaf rust, caused by Puccinia triticina, and stem rust, caused by P. graminis f. sp. tritici, are important diseases of durum wheat. This study determined the inheritance and genomic locations of leaf rust resistance (Lr) genes to P. triticina race BBBQJ and stem rust resistance (Sr) genes to P. graminis f. sp. tritici race TTKSK in durum accessions. Eight leaf-rust-resistant genotypes were used to develop biparental populations. Accessions PI 192051 and PI 534304 were also resistant to P. graminis f. sp. tritici race TTKSK. The resulting progenies were phenotyped for leaf rust and stem rust response at seedling stage. The Lr and Sr genes were mapped in five populations using single-nucleotide polymorphisms and bulked segregant analysis. Five leaf-rust-resistant genotypes carried single dominant Lr genes whereas, in the remaining accessions, there was deviation from the expected segregation ratio of a single dominant Lr gene. Seven genotypes carried Lr genes different from those previously characterized in durum. The single dominant Lr genes in PI 209274, PI 244061, PI387263, and PI 313096 were mapped to chromosome arms 6BS, 2BS, 6BL, and 6BS, respectively. The Sr gene in PI 534304 mapped to 6AL and is most likely Sr13, while the Sr gene in PI 192051 could be uncharacterized in durum.

Approaches to understanding the impact of life-history features on plant-pathogen co-evolutionary dynamics

Treesearch

Jeremy J. Burdon; Peter H. Thrall; Adnane Nemri

2012-01-01

Natural plant-pathogen associations are complex interactions in which the interplay of environment, host, and pathogen factors results in spatially heterogeneous ecological and epidemiological dynamics. The evolutionary patterns that result from the interaction of these factors are still relatively poorly understood. Recently, integration of the appropriate spatial and...

Restructuring of Educational Systems in the Digital Age from a Co-Evolutionary Perspective

ERIC Educational Resources Information Center

Davis, N.; Eickelmann, B.; Zaka, P.

2013-01-01

There have been repeated calls for restructuring of schooling to take advantage of information and communication technologies (ICT). This article recognizes an increasing range of radical restructuring resulting from the co-evolution of education and digital technologies in school systems and related activity in the global ecosystem. Research of…

A survey of the foliar and soil arthropod communities in sunflower (Helianthus annuus) fields in central and eastern South Dakota

USDA-ARS?s Scientific Manuscript database

The long coevolutionary history between sunflowers (Helianthus annuus, Asterales: Asteraceae) and arthropods in the Northern Great Plains has resulted in a commonly grown oilseed crop that harbors a large diversity of insects. A bioenventory of foliar and subterranean arthropods was performed in 22 ...

A further analysis of the role of heterogeneity in coevolutionary spatial games

NASA Astrophysics Data System (ADS)

Cardinot, Marcos; Griffith, Josephine; O'Riordan, Colm

2018-03-01

Heterogeneity has been studied as one of the most common explanations of the puzzle of cooperation in social dilemmas. A large number of papers have been published discussing the effects of increasing heterogeneity in structured populations of agents, where it has been established that heterogeneity may favour cooperative behaviour if it supports agents to locally coordinate their strategies. In this paper, assuming an existing model of a heterogeneous weighted network, we aim to further this analysis by exploring the relationship (if any) between heterogeneity and cooperation. We adopt a weighted network which is fully populated by agents playing both the Prisoner's Dilemma or the Optional Prisoner's Dilemma games with coevolutionary rules, i.e., not only the strategies but also the link weights evolve over time. Surprisingly, results show that the heterogeneity of link weights (states) on their own does not always promote cooperation; rather cooperation is actually favoured by the increase in the number of overlapping states and not by the heterogeneity itself. We believe that these results can guide further research towards a more accurate analysis of the role of heterogeneity in social dilemmas.

The bacterial parasite Pasteuria ramosa is not killed if it fails to infect: implications for coevolution

PubMed Central

King, Kayla C; Auld, Stuart K J R; Wilson, Philip J; James, Janna; Little, Tom J

2013-01-01

Strong selection on parasites, as well as on hosts, is crucial for fueling coevolutionary dynamics. Selection will be especially strong if parasites that encounter resistant hosts are destroyed and diluted from the local environment. We tested whether spores of the bacterial parasite Pasteuria ramosa were passed through the gut (the route of infection) of their host, Daphnia magna, and whether passaged spores remained viable for a “second chance” at infecting a new host. In particular, we tested if this viability (estimated via infectivity) depended on host genotype, whether or not the genotype was susceptible, and on initial parasite dose. Our results show that Pasteuria spores generally remain viable after passage through both susceptible and resistant Daphnia. Furthermore, these spores remained infectious even after being frozen for several weeks. If parasites can get a second chance at infecting hosts in the wild, selection for infection success in the first instance will be reduced. This could also weaken reciprocal selection on hosts and slow the coevolutionary process. PMID:23467806

Upper Extremity Injuries in NASCAR Drivers and Pit Crew: An Epidemiological Study.

PubMed

Wertman, Gary; Gaston, R Glenn; Heisel, William

2016-02-01

Understanding the position-specific musculoskeletal forces placed on the body of athletes facilitates treatment, prevention, and return-to-play decisions. While position-specific injuries are well documented in most major sports, little is known about the epidemiology of position-specific injuries in National Association for Stock Car Automobile Racing (NASCAR) drivers and pit crew. To investigate position-specific upper extremity injuries in NASCAR drivers and pit crew members. Descriptive epidemiological study. A retrospective chart review was performed to assess position-specific injuries in NASCAR drivers and pit crew members. Included in the study were patients seen by a single institution between July 2003 and October 2014 with upper extremity injuries from race-related NASCAR events or practices. Charts were reviewed to identify the diagnosis, mechanism of injury, and position of each patient. A total of 226 NASCAR team members were treated between July 2003 and October 2014. Of these, 118 injuries (52%) occurred during NASCAR racing events or practices. The majority of these injuries occurred in NASCAR changers (42%), followed by injuries in drivers (16%), carriers (14%), jack men (11%), fuel men (9%), and utility men (8%). The majority of the pit crew positions are at risk for epicondylitis, while drivers are most likely to experience neuropathies, such as hand-arm vibration syndrome. The changer sustains the most hand-related injuries (42%) on the pit crew team, while carriers commonly sustain injuries to their digits (29%). Orthopaedic injuries in NASCAR vary between positions. Injuries in NASCAR drivers and pit crew members are a consequence of the distinctive forces associated with each position throughout the course of the racing season. Understanding these forces and position-associated injuries is important for preventive measures and facilitates diagnosis and return-to-play decisions so that each team can function at its maximal efficiency.

Comparison of training and anthropometric characteristics between recreational male half-marathoners and marathoners.

PubMed

Zillmann, Teresa; Knechtle, Beat; Rüst, Christoph Alexander; Knechtle, Patrizia; Rosemann, Thomas; Lepers, Romuald

2013-06-30

Participation in endurance running such as half-marathon (21-km) and marathon (42-km) has increased over the last decades. We compared 147 recreational male half-marathoners and 126 recreational male marathoners to investigate similarities or differences in their anthropometric and training characteristics. The half-marathoners were heavier (P < 0.05), had longer legs (P < 0.001), thicker upper arms (P < 0.05), a thicker thigh (P < 0.01), a higher sum of skinfold thicknesses (P < 0.01), a higher body fat percentage (P < 0.05) and a higher skeletal muscle mass (P < 0.05) than the marathoners. They had fewer years of experience (P < 0.05), completed fewer weekly training kilometers (P < 0.001), and fewer weekly running hours (P < 0.01) compared to the marathoners. For half-marathoners, body mass index (P = 0.011), percent body fat (P = 0.036) and speed in running during training (P < 0.0001) were related to race time (r2 = 0.47). For marathoners, percent body fat (P = 0.001) and speed in running during training (P < 0.0001) were associated to race time (r2 = 0.47). When body mass index was excluded for the half-marathoners in the multi-variate analysis, r2 decreased to 0.45, therefore body mass index explained only 2% of the variance of half-marathon performance. Percent body fat was significantly and negatively related to running speed during training in both groups. To summarize, half-marathoners showed differences in both anthropometry and training characteristics compared to marathoners that could be related to their lower training volume, most probably due to the shorter race distance they intended to compete. Both groups of athletes seemed to profit from low body fat and a high running speed during training for fast race times.

Black breast cancer survivors experience greater upper extremity disability.

PubMed

Dean, Lorraine T; DeMichele, Angela; LeBlanc, Mously; Stephens-Shields, Alisa; Li, Susan Q; Colameco, Chris; Coursey, Morgan; Mao, Jun J

2015-11-01

Over one-third of breast cancer survivors experience upper extremity disability. Black women present with factors associated with greater upper extremity disability, including: increased body mass index (BMI), more advanced disease stage at diagnosis, and varying treatment type compared with Whites. No prior research has evaluated the relationship between race and upper extremity disability using validated tools and controlling for these factors. Data were drawn from a survey study among 610 women with stage I-III hormone receptor positive breast cancer. The disabilities of the arm, shoulder and hand (QuickDASH) is an 11-item self-administered questionnaire that has been validated for breast cancer survivors to assess global upper extremity function over the past 7 days. Linear regression and mediation analysis estimated the relationships between race, BMI and QuickDASH score, adjusting for demographics and treatment types. Black women (n = 98) had 7.3 points higher average QuickDASH scores than White (n = 512) women (p < 0.001). After adjusting for BMI, age, education, cancer treatment, months since diagnosis, and aromatase inhibitor status, Black women had an average 4-point (95 % confidence interval 0.18-8.01) higher QuickDASH score (p = 0.04) than White women. Mediation analysis suggested that BMI attenuated the association between race and disability by 40 %. Even several years post-treatment, Black breast cancer survivors had greater upper extremity disability, which was partially mediated by higher BMIs. Close monitoring of high BMI Black women may be an important step in reducing disparities in cancer survivorship. More research is needed on the relationship between race, BMI, and upper extremity disability.

Role of glycogen availability in sarcoplasmic reticulum Ca2+ kinetics in human skeletal muscle

PubMed Central

Ørtenblad, Niels; Nielsen, Joachim; Saltin, Bengt; Holmberg, Hans-Christer

2011-01-01

Little is known about the precise mechanism that relates skeletal muscle glycogen to muscle fatigue. The aim of the present study was to examine the effect of glycogen on sarcoplasmic reticulum (SR) function in the arm and leg muscles of elite cross-country skiers (n= 10, 72 ± 2 ml kg−1 min−1) before, immediately after, and 4 h and 22 h after a fatiguing 1 h ski race. During the first 4 h recovery, skiers received either water or carbohydrate (CHO) and thereafter all received CHO-enriched food. Immediately after the race, arm glycogen was reduced to 31 ± 4% and SR Ca2+ release rate decreased to 85 ± 2% of initial levels. Glycogen noticeably recovered after 4 h recovery with CHO (59 ± 5% initial) and the SR Ca2+ release rate returned to pre-exercise levels. However, in the absence of CHO during the first 4 h recovery, glycogen and the SR Ca2+ release rate remained unchanged (29 ± 2% and 77 ± 8%, respectively), with both parameters becoming normal after the remaining 18 h recovery with CHO. Leg muscle glycogen decreased to a lesser extent (71 ± 10% initial), with no effects on the SR Ca2+ release rate. Interestingly, transmission electron microscopy (TEM) analysis revealed that the specific pool of intramyofibrillar glycogen, representing 10–15% of total glycogen, was highly significantly correlated with the SR Ca2+ release rate. These observations strongly indicate that low glycogen and especially intramyofibrillar glycogen, as suggested by TEM, modulate the SR Ca2+ release rate in highly trained subjects. Thus, low glycogen during exercise may contribute to fatigue by causing a decreased SR Ca2+ release rate. PMID:21135051

Computational Analyses of an Evolutionary Arms Race between Mammalian Immunity Mediated by Immunoglobulin A and Its Subversion by Bacterial Pathogens

PubMed Central

Pinheiro, Ana; Woof, Jenny M.; Abi-Rached, Laurent; Parham, Peter; Esteves, Pedro J.

2013-01-01

IgA is the predominant immunoglobulin isotype in mucosal tissues and external secretions, playing important roles both in defense against pathogens and in maintenance of commensal microbiota. Considering the complexity of its interactions with the surrounding environment, IgA is a likely target for diversifying or positive selection. To investigate this possibility, the action of natural selection on IgA was examined in depth with six different methods: CODEML from the PAML package and the SLAC, FEL, REL, MEME and FUBAR methods implemented in the Datamonkey webserver. In considering just primate IgA, these analyses show that diversifying selection targeted five positions of the Cα1 and Cα2 domains of IgA. Extending the analysis to include other mammals identified 18 positively selected sites: ten in Cα1, five in Cα2 and three in Cα3. All but one of these positions display variation in polarity and charge. Their structural locations suggest they indirectly influence the conformation of sites on IgA that are critical for interaction with host IgA receptors and also with proteins produced by mucosal pathogens that prevent their elimination by IgA-mediated effector mechanisms. Demonstrating the plasticity of IgA in the evolution of different groups of mammals, only two of the eighteen selected positions in all mammals are included in the five selected positions in primates. That IgA residues subject to positive selection impact sites targeted both by host receptors and subversive pathogen ligands highlights the evolutionary arms race playing out between mammals and pathogens, and further emphasizes the importance of IgA in protection against mucosal pathogens. PMID:24019941

Water administration and the risk of syncope and pre-syncope during blood donation: a randomized clinical trial

PubMed Central

van den Berg, Karin; Lam, Jameson; Bruhn, Roberta; Custer, Brian; Murphy, Edward L

2012-01-01

Background Blood centers rely heavily upon adolescent donors to meet blood demand, but pre-syncope and syncope are more frequent in younger donors. Studies have suggested administration of water prior to donation may reduce syncope and/or pre-syncope in this group. Study design and methods We conducted a randomized, controlled trial to establish the effect of pre-loading with 500ml of water on the rate of syncope and pre-syncope in adolescent donors. School collection sites in Eastern Cape Province of South Africa were randomized to receive water or not. Incidence of syncope and pre-syncope was compared between randomization groups using multivariable logistic regression. Results Of 2,464 study participants, 1,337 received water and 1,127 did not; groups differed slightly by gender and race. Syncope or pre-syncope was seen in 23 (1.7%) of the treatment and 18 (1.6%) of the control arm subjects. After adjusting for race, gender, age and donation history, there was no difference in outcome between the water versus no water arms (adjusted odds ratio (OR) = 0.80 (95% CI 0.42–1.53). Black donors had 7-fold lower odds of syncope or pre-syncope than their white counterparts (adjusted OR 0.14, 95% CI 0.04–0.47). Conclusion Preloading adolescent donors with 500ml of water did not have a major effect in reducing syncope and pre-syncope in South African adolescent donors. Our adolescent donors had a lower overall syncope and pre-syncope rate than similar populations in the USA, limiting the statistical power of the study. We confirmed much lower rates of syncope and pre-syncope among young Black donors. PMID:22486209

The Weak Shall Inherit: Bacteriocin-Mediated Interactions in Bacterial Populations

PubMed Central

Majeed, Hadeel; Lampert, Adam; Ghazaryan, Lusine; Gillor, Osnat

2013-01-01

Background Evolutionary arms race plays a major role in shaping biological diversity. In microbial systems, competition often involves chemical warfare and the production of bacteriocins, narrow-spectrum toxins aimed at killing closely related strains by forming pores in their target’s membrane or by degrading the target’s RNA or DNA. Although many empirical and theoretical studies describe competitive exclusion of bacteriocin-sensitive strains by producers of bacteriocins, the dynamics among producers are largely unknown. Methodology/Principal findings We used a reporter-gene assay to show that the bacterial response to bacteriocins’ treatment mirrors the inflicted damage Potent bacteriocins are lethal to competing strains, but at sublethal doses can serve as strong inducing agents, enhancing their antagonists’ bacteriocin production. In contrast, weaker bacteriocins are less toxic to their competitors and trigger mild bacteriocin expression. We used empirical and numerical models to explore the role of cross-induction in the arms race between bacteriocin-producing strains. We found that in well-mixed, unstructured environments where interactions are global, producers of weak bacteriocins are selectively advantageous and outcompete producers of potent bacteriocins. However, in spatially structured environments, where interactions are local, each producer occupies its own territory, and competition takes place only in “no man’s lands” between territories, resulting in much slower dynamics. Conclusion/Significance The models we present imply that producers of potent bacteriocins that trigger a strong response in neighboring bacteriocinogenic strains are doomed, while producers of weak bacteriocins that trigger a mild response in bacteriocinogenic strains flourish. This counter-intuitive outcome might explain the preponderance of weak bacteriocin producers in nature. However, the described scenario is prolonged in spatially structured environments thus promoting coexistence, allowing migration and evolution, and maintaining bacterial diversity. PMID:23704942

Is race a determinant of stillbirth recurrence?

PubMed

Sharma, Puza P; Salihu, Hamisu M; Oyelese, Yinka; Ananth, Cande V; Kirby, Russell S

2006-02-01

A history of stillbirth may result in an increased risk for recurrence, although information regarding this remains scanty. It is also uncertain whether race is a determinant of stillbirth recurrence given that the risk of stillbirth varies across racial and ethnic populations. The Missouri maternally linked cohort data set containing births from 1978 through 1997 was used. We identified the study group (women who experienced a stillbirth in the first pregnancy) and a comparison group (women who delivered a live birth in their first pregnancy) and compared the outcome (stillbirth) in the second pregnancy between the 2 groups. We analyzed 404,180 women with information on first and second pregnancies (1,979 [0.5%] in the study arm, and 402,201 [99.5%] in the comparison arm). Of the 1,929 cases of stillbirths in the second pregnancy, 45 cases occurred in mothers with a history of stillbirth (stillbirth rate = 22.7/1000) and 1,884 in the comparison group (stillbirth rate 4.7/1,000, P < .001). The adjusted risk of stillbirth was almost 5-fold as high in women with a prior stillbirth (odds ratio 4.7, 95% confidence interval 3.3-6.6). Analysis across racial groups revealed that whites had lower absolute risk for stillbirth recurrence than African Americans (19.1/1,000 compared with 35.9/1,000, P < .05). The elevated stillbirth recurrence risk was confirmed after adjusting for potential confounders (odds ratio 2.6, 95% confidence interval 1.2-5.7). History of stillbirth is associated with a 5-fold increase for subsequent stillbirth. The recurrence of stillbirth is almost tripled in African Americans as compared with whites. II-2.

Virions at the gates: receptors and the host-virus arms race.

PubMed

Coffin, John M

2013-01-01

All viruses need to bind to specific receptor molecules on the surface of target cells to initiate infection. Virus-receptor binding is highly specific, and this specificity determines both the species and the cell type that can be infected by a given virus. In some well-studied cases, the virus-binding region on the receptor has been found to be unrelated to the receptor's normal cellular function. Resistance to virus infection can thus evolve by selection of mutations that alter amino acids in the binding region with minimal effect on normal function. This sort of positive selection can be used to infer the history of the host-virus "arms race" during their coevolution. In a new study, Demogines et al. use a combination of phylogenetic, structural, and virological analysis to infer the history and significance of positive selection on the transferrin receptor TfR1, a housekeeping protein required for iron uptake and the cell surface receptor for at least three different types of virus. The authors show that only two parts of the rodent TfR1 molecule have been subject to positive selection and that these correspond to the binding sites for two of these viruses-the mouse mammary tumor virus (a retrovirus) and Machupo virus (an arenavirus). They confirmed this result by introducing the inferred binding site mutations into the wild-type protein and testing for receptor function. Related arenaviruses are beginning to spread in human populations in South America as the cause of often fatal hemorrhagic fevers, and, although Demogines et al. could find no evidence of TfR1 mutations in this region that might have been selected as a consequence of human infection, the authors identified one such mutation in Asian populations that affects infection with these viruses.

Arms race between weevil rostrum length and camellia pericarp thickness: Geographical cline and theory.

PubMed

Iseki, Naoyuki; Sasaki, Akira; Toju, Hirokazu

2011-09-21

The geographical cline of the coevolving traits of weevil rostrum (mouthpart) length and camellia pericarp (fruit coat) thickness provides an opportunity to test the arms race theory of defense (pericarp thickness) and countermeasure (rostrum length) between antagonistically interacting species. By extending the previous model for the coevolution of quantitative traits to introduce nonlinear costs for exaggerated traits, the generation overlap, and density-dependent regulation in the host, we studied the evolutionarily stable (ES) pericarp thickness in the Japanese camellia (Camellia japonica) and the ES rostrum length in the camellia-weevil (Curculio camelliae). The joint monomorphic ES system has a robust outcome with nonlinear costs, and we analyzed how the traits of both species at evolutionary equilibrium depend on demographic parameters. If camellia demographic parameters vary latitudinally, data collected over the geographical scale of rostrum length and pericarp thickness should lie on an approximately linear curve with the slope less than that of the equiprobability line A/B of boring success, where A and B are coefficients for the logistic regression of boring success to pericarp thickness and rostrum length, respectively. This is a robust prediction as long as the cost of rostrum length is nonlinear (accelerating). As a result, boring success should be lower in populations with longer rostrum length, as reported in the weevil-camellia system (Toju, H., and Sota, T., 2006a. Imbalance of predator and prey armament: Geographic clines in phenotypic interface and natural selection. American Naturalist 167, 105-117). The nonlinearity (exponent) for the cost of rostrum length estimated from the geographical cline data for the weevil-camellia system was 2.2, suggesting nonlinearity between quadratic and cubic forms. Copyright © 2011 Elsevier Ltd. All rights reserved.

An experimental and computational evolution-based method to study a mode of co-evolution of overlapping open reading frames in the AAV2 viral genome.

PubMed

Kawano, Yasuhiro; Neeley, Shane; Adachi, Kei; Nakai, Hiroyuki

2013-01-01

Overlapping open reading frames (ORFs) in viral genomes undergo co-evolution; however, how individual amino acids coded by overlapping ORFs are structurally, functionally, and co-evolutionarily constrained remains difficult to address by conventional homologous sequence alignment approaches. We report here a new experimental and computational evolution-based methodology to address this question and report its preliminary application to elucidating a mode of co-evolution of the frame-shifted overlapping ORFs in the adeno-associated virus (AAV) serotype 2 viral genome. These ORFs encode both capsid VP protein and non-structural assembly-activating protein (AAP). To show proof of principle of the new method, we focused on the evolutionarily conserved QVKEVTQ and KSKRSRR motifs, a pair of overlapping heptapeptides in VP and AAP, respectively. In the new method, we first identified a large number of capsid-forming VP3 mutants and functionally competent AAP mutants of these motifs from mutant libraries by experimental directed evolution under no co-evolutionary constraints. We used Illumina sequencing to obtain a large dataset and then statistically assessed the viability of VP and AAP heptapeptide mutants. The obtained heptapeptide information was then integrated into an evolutionary algorithm, with which VP and AAP were co-evolved from random or native nucleotide sequences in silico. As a result, we demonstrate that these two heptapeptide motifs could exhibit high degeneracy if coded by separate nucleotide sequences, and elucidate how overlap-evoked co-evolutionary constraints play a role in making the VP and AAP heptapeptide sequences into the present shape. Specifically, we demonstrate that two valine (V) residues and β-strand propensity in QVKEVTQ are structurally important, the strongly negative and hydrophilic nature of KSKRSRR is functionally important, and overlap-evoked co-evolution imposes strong constraints on serine (S) residues in KSKRSRR, despite high degeneracy of the motifs in the absence of co-evolutionary constraints.

Complex coevolutionary history of symbiotic Bacteroidales bacteria of various protists in the gut of termites

PubMed Central

Noda, Satoko; Hongoh, Yuichi; Sato, Tomoyuki; Ohkuma, Moriya

2009-01-01

Background The microbial community in the gut of termites is responsible for the efficient decomposition of recalcitrant lignocellulose. Prominent features of this community are its complexity and the associations of prokaryotes with the cells of cellulolytic flagellated protists. Bacteria in the order Bacteroidales are involved in associations with a wide variety of gut protist species as either intracellular endosymbionts or surface-attached ectosymbionts. In particular, ectosymbionts exhibit distinct morphological patterns of the associations. Therefore, these Bacteroidales symbionts provide an opportunity to investigate not only the coevolutionary relationships with the host protists and their morphological evolution but also how symbiotic associations between prokaryotes and eukaryotes occur and evolve within a complex symbiotic community. Results Molecular phylogeny of 31 taxa of Bacteroidales symbionts from 17 protist genera in 10 families was examined based on 16S rRNA gene sequences. Their localization, morphology, and specificity were also examined by fluorescent in situ hybridizations. Although a monophyletic grouping of the ectosymbionts occurred in three related protist families, the symbionts of different protist genera were usually dispersed among several phylogenetic clusters unique to termite-gut bacteria. Similar morphologies of the associations occurred in multiple lineages of the symbionts. Nevertheless, the symbionts of congeneric protist species were closely related to one another, and in most cases, each host species harbored a unique Bacteroidales species. The endosymbionts were distantly related to the ectosymbionts examined so far. Conclusion The coevolutionary history of gut protists and their associated Bacteroidales symbionts is complex. We suggest multiple independent acquisitions of the Bacteroidales symbionts by different protist genera from a pool of diverse bacteria in the gut community. In this sense, the gut could serve as a reservoir of diverse bacteria for associations with the protist cells. The similar morphologies are considered a result of evolutionary convergence. Despite the complicated evolutionary history, the host-symbiont relationships are mutually specific, suggesting their cospeciations at the protist genus level with only occasional replacements. PMID:19586555

Evolutionary Diversification of Prey and Predator Species Facilitated by Asymmetric Interactions

PubMed Central

Zu, Jian; Wang, Jinliang; Huang, Gang

2016-01-01

We investigate the influence of asymmetric interactions on coevolutionary dynamics of a predator-prey system by using the theory of adaptive dynamics. We assume that the defense ability of prey and the attack ability of predators all can adaptively evolve, either caused by phenotypic plasticity or by behavioral choice, but there are certain costs in terms of their growth rate or death rate. The coevolutionary model is constructed from a deterministic approximation of random mutation-selection process. To sum up, if prey’s trade-off curve is globally weakly concave, then five outcomes of coevolution are demonstrated, which depend on the intensity and shape of asymmetric predator-prey interactions and predator’s trade-off shape. Firstly, we find that if there is a weakly decelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species may occur, but after branching further coevolution may lead to extinction of the predator species with a larger trait value. However, if there is a weakly accelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species is also possible and after branching the dimorphic predator can evolutionarily stably coexist with a monomorphic prey species. Secondly, if the asymmetric interactions become a little strong, then prey and predators will evolve to an evolutionarily stable equilibrium, at which they can stably coexist on a long-term timescale of evolution. Thirdly, if there is a weakly accelerating cost and a relatively strongly accelerating benefit for prey species, then evolutionary branching in the prey species is possible and the finally coevolutionary outcome contains a dimorphic prey and a monomorphic predator species. Fourthly, if the asymmetric interactions become more stronger, then predator-prey coevolution may lead to cycles in both traits and equilibrium population densities. The Red Queen dynamic is a possible outcome under asymmetric predator-prey interactions. PMID:27685540

Evolutionary Diversification of Prey and Predator Species Facilitated by Asymmetric Interactions.

PubMed

Zu, Jian; Wang, Jinliang; Huang, Gang

We investigate the influence of asymmetric interactions on coevolutionary dynamics of a predator-prey system by using the theory of adaptive dynamics. We assume that the defense ability of prey and the attack ability of predators all can adaptively evolve, either caused by phenotypic plasticity or by behavioral choice, but there are certain costs in terms of their growth rate or death rate. The coevolutionary model is constructed from a deterministic approximation of random mutation-selection process. To sum up, if prey's trade-off curve is globally weakly concave, then five outcomes of coevolution are demonstrated, which depend on the intensity and shape of asymmetric predator-prey interactions and predator's trade-off shape. Firstly, we find that if there is a weakly decelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species may occur, but after branching further coevolution may lead to extinction of the predator species with a larger trait value. However, if there is a weakly accelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species is also possible and after branching the dimorphic predator can evolutionarily stably coexist with a monomorphic prey species. Secondly, if the asymmetric interactions become a little strong, then prey and predators will evolve to an evolutionarily stable equilibrium, at which they can stably coexist on a long-term timescale of evolution. Thirdly, if there is a weakly accelerating cost and a relatively strongly accelerating benefit for prey species, then evolutionary branching in the prey species is possible and the finally coevolutionary outcome contains a dimorphic prey and a monomorphic predator species. Fourthly, if the asymmetric interactions become more stronger, then predator-prey coevolution may lead to cycles in both traits and equilibrium population densities. The Red Queen dynamic is a possible outcome under asymmetric predator-prey interactions.

From engineering hydrology to Earth system science: milestones in the transformation of hydrologic science

NASA Astrophysics Data System (ADS)

Sivapalan, Murugesu

2018-03-01

Hydrology has undergone almost transformative changes over the past 50 years. Huge strides have been made in the transition from early empirical approaches to rigorous approaches based on the fluid mechanics of water movement on and below the land surface. However, progress has been hampered by problems posed by the presence of heterogeneity, including subsurface heterogeneity present at all scales. The inability to measure or map the heterogeneity everywhere prevented the development of balance equations and associated closure relations at the scales of interest, and has led to the virtual impasse we are presently in, in terms of development of physically based models needed for hydrologic predictions. An alternative to the mapping of heterogeneity everywhere is a new Earth system science view, which sees the heterogeneity as the end result of co-evolutionary hydrological, geomorphological, ecological, and pedological processes, each operating at a different rate, which help to shape the landscapes that we find in nature, including the heterogeneity that we do not readily see. The expectation is that instead of specifying exact details of the heterogeneity in our models, we can replace it (without loss of information) with the ecosystem function that they perform. Guided by this new Earth system science perspective, development of hydrologic science is now addressing new questions using novel holistic co-evolutionary approaches as opposed to the physical, fluid mechanics based reductionist approaches that we inherited from the recent past. In the emergent Anthropocene, the co-evolutionary view has expanded further to involve interactions and feedbacks with human-social processes as well. In this paper, I present my own perspective of key milestones in the transformation of hydrologic science from engineering hydrology to Earth system science, drawn from the work of several students and colleagues of mine, and discuss their implication for hydrologic observations, theory development, and predictions.

Diversity patterns amongst herbivorous dinosaurs and plants during the Cretaceous: implications for hypotheses of dinosaur/angiosperm co-evolution.

PubMed

Butler, R J; Barrett, P M; Kenrick, P; Penn, M G

2009-03-01

Palaeobiologists frequently attempt to identify examples of co-evolutionary interactions over extended geological timescales. These hypotheses are often intuitively appealing, as co-evolution is so prevalent in extant ecosystems, and are easy to formulate; however, they are much more difficult to test than their modern analogues. Among the more intriguing deep time co-evolutionary scenarios are those that relate changes in Cretaceous dinosaur faunas to the primary radiation of flowering plants. Demonstration of temporal congruence between the diversifications of co-evolving groups is necessary to establish whether co-evolution could have occurred in such cases, but is insufficient to prove whether it actually did take place. Diversity patterns do, however, provide a means for falsifying such hypotheses. We have compiled a new database of Cretaceous dinosaur and plant distributions from information in the primary literature. This is used as the basis for plotting taxonomic diversity and occurrence curves for herbivorous dinosaurs (Sauropodomorpha, Stegosauria, Ankylosauria, Ornithopoda, Ceratopsia, Pachycephalosauria and herbivorous theropods) and major groups of plants (angiosperms, Bennettitales, cycads, cycadophytes, conifers, Filicales and Ginkgoales) that co-occur in dinosaur-bearing formations. Pairwise statistical comparisons were made between various floral and faunal groups to test for any significant similarities in the shapes of their diversity curves through time. We show that, with one possible exception, diversity patterns for major groups of herbivorous dinosaurs are not positively correlated with angiosperm diversity. In other words, at the level of major clades, there is no support for any diffuse co-evolutionary relationship between herbivorous dinosaurs and flowering plants. The diversification of Late Cretaceous pachycephalosaurs (excluding the problematic taxon Stenopelix) shows a positive correlation, but this might be spuriously related to poor sampling in the Turonian-Santonian interval. Stegosauria shows a significant negative correlation with flowering plants and a significant positive correlation with the nonflowering cycadophytes (cycads, Bennettitales). This interesting pattern is worthy of further investigation, and it reflects the decline of both stegosaurs and cycadophytes during the Early Cretaceous.

The Conundrum of Modern Art : Prestige-Driven Coevolutionary Aesthetics Trumps Evolutionary Aesthetics among Art Experts.

PubMed

Verpooten, Jan; Dewitte, Siegfried

2017-03-01

Two major mechanisms of aesthetic evolution have been suggested. One focuses on naturally selected preferences (Evolutionary Aesthetics), while the other describes a process of evaluative coevolution whereby preferences coevolve with signals. Signaling theory suggests that expertise moderates these mechanisms. In this article we set out to verify this hypothesis in the domain of art and use it to elucidate Western modern art's deviation from naturally selected preferences. We argue that this deviation is consistent with a Coevolutionary Aesthetics mechanism driven by prestige-biased social learning among art experts. In order to test this hypothesis, we conducted two studies in which we assessed the effects on lay and expert appreciation of both the biological relevance of the given artwork's depicted content, viz., facial beauty, and the prestige specific to the artwork's associated context (MoMA). We found that laypeople appreciate artworks based on their depictions of facial beauty, mediated by aesthetic pleasure, which is consistent with previous studies. In contrast, experts appreciate the artworks based on the prestige of the associated context, mediated by admiration for the artist. Moreover, experts appreciate artworks depicting neutral faces to a greater degree than artworks depicting attractive faces. These findings thus corroborate our contention that expertise moderates the Evolutionary and Coevolutionary Aesthetics mechanisms in the art domain. Furthermore, our findings provide initial support for our proposal that prestige-driven coevolution with expert evaluations plays a decisive role in modern art's deviation from naturally selected preferences. After discussing the limitations of our research as well as the relation that our results bear on cultural evolution theory, we provide a number of suggestions for further research into the potential functions of expert appreciation that deviates from naturally selected preferences, on the one hand, and expertise as a moderator of these mechanisms in other cultural domains, on the other.

Specificity of a Rust Resistance Suppressor on 7DL in the Spring Wheat Cultivar Canthatch.

PubMed

Talajoor, Mina; Jin, Yue; Wan, Anmin; Chen, Xianming; Bhavani, Sridhar; Tabe, Linda; Lagudah, Evans; Huang, Li

2015-04-01

The spring wheat 'Canthatch' has been shown to suppress stem rust resistance genes in the background due to the presence of a suppressor gene located on the long arm of chromosome 7D. However, it is unclear whether the suppressor also suppresses resistance genes against leaf rust and stripe rust. In this study, we investigated the specificity of the resistance suppression. To determine whether the suppression is genome origin specific, chromosome location specific, or rust species or race specific, we introduced 11 known rust resistance genes into the Canthatch background, including resistance to leaf, stripe, or stem rusts, originating from A, B, or D genomes and located on different chromosome homologous groups. F1 plants of each cross were tested with the corresponding rust race, and the infection types were scored and compared with the parents. Our results show that the Canthatch 7DL suppressor only suppressed stem rust resistance genes derived from either the A or B genome, and the pattern of the suppression is gene specific and independent of chromosomal location.

Rapid change of chromomeric and pairing patterns of polytene chromosome tips in D. melanogaster: migration of polytene-nonpolytene transition zone?

PubMed

Roberts, P A

1979-07-01

The high variability of chromomeric patterns in near-terminal regions of polytene chromosome arms has been explored in a number of races, strains and hybrids of Drosophila melanogaster. Traditional explanations for tip differences between strains (differential compaction of chromatin, somatic or germinal deletion) are examined and, in the light of the reported observations, rejected. The range of polytene tip variability and rates of change in wild races are greater than has been supposed: strains formerly considered to be terminally deleted appear to gain terminal bands; others, formerly considered normal, appear to have lost them. Strains with high cell-to-cell tip variability are also described. Cell-to-cell variations, as well as much of the observed rapid changes in tip appearance, are probably due to heritable differences in the location of an abrupt transition zone between polytene and nonpolytene chromatin. A quantitative relationship between the amount of certain subterminal bands present and the frequency of tip association of nonhomologous chromosomes is shown and its possible significance for chromosome is shown and its possible for chromosome pairing discussed.

No evidence for host specialization or host-race formation in the European bitterling (Rhodeus amarus), a fish that parasitizes freshwater mussels.

PubMed

Reichard, M; Bryja, J; Polačik, M; Smith, C

2011-09-01

Coevolutionary relationships between parasites and hosts can elevate the rate of evolutionary changes owing to reciprocal adaptations between coevolving partners. Such relationships can result in the evolution of host specificity. Recent methodological advances have permitted the recognition of cryptic lineages, with important consequences for our understanding of biological diversity. We used the European bitterling (Rhodeus amarus), a freshwater fish that parasitizes unionid mussels, to investigate host specialization across regions of recent and ancient sympatry between coevolving partners. We combined genetic data (12 microsatellite and 2 mitochondrial markers) from five populations with experimental data for possible mechanisms of host species recognition (imprinting and conditioning). We found no strong evidence for the existence of cryptic lineages in R. amarus, though a small proportion of variation among individuals in an area of recent bitterling-mussel association was statistically significant in explaining host specificity. No other measures supported the existence of host-specific lineages. Behavioural data revealed a weak effect of conditioning that biased behavioural preferences towards specific host species. Host imprinting had no effect on oviposition behaviour. Overall, we established that populations of R. amarus show limited potential for specialization, manifested as weak effects of host conditioning and genetic within-population structure. Rhodeus amarus is the only species of mussel-parasitizing fish in Europe, which contrasts with the species-rich communities of bitterling in eastern Asia where several host-specific bitterling occur. We discuss costs and constraints on the evolution of host-specific lineages in our study system and more generally. © 2011 Blackwell Publishing Ltd.

Coevolutionary dynamics of rice blast resistance gene Pi-ta and Magnaporthe oryzae avirulence gene AVR-Pita 1

USDA-ARS?s Scientific Manuscript database

The Pi-ta gene in rice is effective in preventing infections by Magnaporthe oryzae strains that contain the corresponding avirulence gene, AVR-Pita1. Genome sequencing and mapping studies demonstrated that AVR-Pita1 is highly unstable, and diverse haplotypes of AVR-Pita1 have been identified from is...

Seed dispersal in limber and southwestern white pine: Comparing core and peripheral populations

Treesearch

Diana F. Tomback; Sheridan Samano; Elizabeth L. Pruett; Anna W. Schoettle

2011-01-01

According to the geographic mosaic theory of coevolution (Thompson 2005), the potential for coevolutionary relationships between interacting species varies with the presence of other species within a community. This implies that the strength of coevolution between two species may vary geographically. In this study, we ask whether there is a shift in vertebrate seed...

The use and application of phylogeography for invertebrate conservation research and planning

Treesearch

Ryan C. Garrick; Chester J. Sands; Paul Sunnucks

2006-01-01

To conserve evolutionary processes within taxa as well as local co-evolutionary associations among taxa, habitat reservation and production forestry management needs to take account of natural genetic-geographic patterns. While vertebrates tend to have at least moderate dispersal and gene flow on a landscape-scale, there are good reasons to expect many small,...

From gun politics to self-defense politics: a feminist critique of the great gun debate.

PubMed

Carlson, Jennifer D

2014-03-01

This article calls attention to a problematic binary produced by public debates surrounding gun rights and gun control-namely, that women must choose armed self-protection or no self-protection at all. I argue that both anti- and pro-gun discourses, drawing on and reproducing race and class privileges, use assumptions about women's physical inferiority to further their agendas. I highlight how both sides have used guns as the proxy for self-defense and conclude by calling for a shift in public discourse to focus on the broader question of the right to self-defense rather than the narrower question of gun rights.

Connective stability of nonlinear matrix systems

NASA Technical Reports Server (NTRS)

Siljak, D. D.

1974-01-01

Consideration of stability under structural perturbations of free dynamic systems described by the differential equation dx/dt = A(t,x)x, where the matrix A(t,x) has time-varying nonlinear elements. The concept of 'connective stability' is introduced to study the structural properties of competitive-cooperative nonlinear matrix systems. It is shown that stability reliability in such systems is high and that they remain stable despite time-varying (including 'on-off') interaction among individual agents present in the system. The results obtained can be used to study stability aspects of mathematical models arising in as diverse fields as economics, biology, arms races, and transistor circuits.

Structural insights into the inactivation of CRISPR-Cas systems by diverse anti-CRISPR proteins.

PubMed

Zhu, Yuwei; Zhang, Fan; Huang, Zhiwei

2018-03-19

A molecular arms race is progressively being unveiled between prokaryotes and viruses. Prokaryotes utilize CRISPR-mediated adaptive immune systems to kill the invading phages and mobile genetic elements, and in turn, the viruses evolve diverse anti-CRISPR proteins to fight back. The structures of several anti-CRISPR proteins have now been reported, and here we discuss their structural features, with a particular emphasis on topology, to discover their similarities and differences. We summarize the CRISPR-Cas inhibition mechanisms of these anti-CRISPR proteins in their structural context. Considering anti-CRISPRs in this way will provide important clues for studying their origin and evolution.

The nuclear weapons freeze and a cancer metaphor. A physician's view.

PubMed

Bruwer, A

1985-08-02

The nuclear arms race has been described as a cancer spreading through human society and threatening its existence. Bruwer characterizes the current superpower reaction to this nuclear threat, deterrence through a mutual weapons buildup, as a palliative approach that can only postpone death. He compares a bilateral weapons freeze to a hypothetical cancer freeze, a strategy that would not get rid of existing arsenals, but would buy negotiating time to work toward the elimination of these weapons. Answering critics who say that a freeze is unrealistic, or does not go far enough, Bruwer reminds them that it would be a beginning.

Programmed cell death as a defence against infection

PubMed Central

Jorgensen, Ine; Rayamajhi, Manira; Miao, Edward A.

2017-01-01

Eukaryotic cells can die from physical trauma, resulting in necrosis. Alternately, they can die via programmed cell death upon stimulation of specific signalling pathways. Here we discuss the utility of four cell death pathways in innate immune defence against bacterial and viral infection: apoptosis, necroptosis, pyroptosis and NETosis. We describe the interactions that interweave different programmed cell death pathways, which create complex signalling networks that cross-guard each other in the evolutionary arms race with pathogens. Finally, we describe how the resulting cell corpses — apoptotic bodies, pore-induced intracellular traps (PITs) and neutrophil extracellular traps (NETs) — promote clearance of infection. PMID:28138137

Supplying the nuclear arsenal: Production reactor technology, management, and policy, 1942--1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlisle, R.P.; Zenzen, J.M.

1994-01-01

This book focuses on the lineage of America`s production reactors, those three at Hanford and their descendants, the reactors behind America`s nuclear weapons. The work will take only occasional sideways glances at the collateral lines of descent, the reactor cousins designed for experimental purposes, ship propulsion, and electric power generation. Over the decades from 1942 through 1992, fourteen American production reactors made enough plutonium to fuel a formidable arsenal of more than twenty thousand weapons. In the last years of that period, planners, nuclear engineers, and managers struggled over designs for the next generation of production reactors. The story ofmore » fourteen individual machines and of the planning effort to replace them might appear relatively narrow. Yet these machines lay at the heart of the nation`s nuclear weapons complex. The story of these machines is the story of arming the winning weapon, supplying the nuclear arms race. This book is intended to capture the history of the first fourteen production reactors, and associated design work, in the face of the end of the Cold War.« less

Type III CRISPR-Cas systems can provide redundancy to counteract viral escape from type I systems

PubMed Central

Silas, Sukrit; Lucas-Elio, Patricia; Jackson, Simon A; Aroca-Crevillén, Alejandra; Hansen, Loren L; Fineran, Peter C

2017-01-01

CRISPR-Cas-mediated defense utilizes information stored as spacers in CRISPR arrays to defend against genetic invaders. We define the mode of target interference and role in antiviral defense for two CRISPR-Cas systems in Marinomonas mediterranea. One system (type I-F) targets DNA. A second system (type III-B) is broadly capable of acquiring spacers in either orientation from RNA and DNA, and exhibits transcription-dependent DNA interference. Examining resistance to phages isolated from Mediterranean seagrass meadows, we found that the type III-B machinery co-opts type I-F CRISPR-RNAs. Sequencing and infectivity assessments of related bacterial and phage strains suggests an ‘arms race’ in which phage escape from the type I-F system can be overcome through use of type I-F spacers by a horizontally-acquired type III-B system. We propose that the phage-host arms race can drive selection for horizontal uptake and maintenance of promiscuous type III interference modules that supplement existing host type I CRISPR-Cas systems. PMID:28826484

Variables that influence Ironman triathlon performance – what changed in the last 35 years?

PubMed Central

Knechtle, Beat; Knechtle, Raphael; Stiefel, Michael; Zingg, Matthias Alexander; Rosemann, Thomas; Rüst, Christoph Alexander

2015-01-01

Objective This narrative review summarizes findings for Ironman triathlon performance and intends to determine potential predictor variables for Ironman race performance in female and male triathletes. Methods A literature search was performed in PubMed using the terms “Ironman”, “triathlon”, and “performance”. All resulting articles were searched for related citations. Results Age, previous experience, sex, training, origin, anthropometric and physiological characteristics, pacing, and performance in split disciplines were predictive. Differences exist between the sexes for anthropometric characteristics. The most important predictive variables for a fast Ironman race time were age of 30–35 years (women and men), a fast personal best time in Olympic distance triathlon (women and men), a fast personal best time in marathon (women and men), high volume and high speed in training where high volume was more important than high speed (women and men), low body fat, low skin-fold thicknesses and low circumference of upper arm (only men), and origin from the United States of America (women and men). Conclusion These findings may help athletes and coaches to plan an Ironman triathlon career. Age and previous experience are important to find the right point in the life of a triathlete to switch from the shorter triathlon distances to the Ironman distance. Future studies need to correlate physiological characteristics such as maximum oxygen uptake with Ironman race time to investigate their potential predictive value and to investigate socio-economic aspects in Ironman triathlon. PMID:26346992

Epidemiology of inflammatory bowel disease in racial and ethnic migrant groups

PubMed Central

Misra, Ravi; Faiz, Omar; Munkholm, Pia; Burisch, Johan; Arebi, Naila

2018-01-01

AIM To summarise the current literature and define patterns of disease in migrant and racial groups. METHODS A structured key word search in Ovid Medline and EMBASE was undertaken in accordance with PRISMA guidelines. Studies on incidence, prevalence and disease phenotype of migrants and races compared with indigenous groups were eligible for inclusion. RESULTS Thirty-three studies met the inclusion criteria. Individual studies showed significant differences in incidence, prevalence and disease phenotype between migrants or race and indigenous groups. Pooled analysis could only be undertaken for incidence studies on South Asians where there was significant heterogeneity between the studies [95% for ulcerative colitis (UC), 83% for Crohn’s disease (CD)]. The difference between incidence rates was not significant with a rate ratio South Asian: Caucasian of 0.78 (95%CI: 0.22-2.78) for CD and 1.39 (95%CI: 0.84-2.32) for UC. South Asians showed consistently higher incidence and more extensive UC than the indigenous population in five countries. A similar pattern was observed for Hispanics in the United States. Bangladeshis and African Americans showed an increased risk of CD with perianal disease. CONCLUSION This review suggests that migration and race influence the risk of developing inflammatory bowel disease. This may be due to different inherent responses upon exposure to an environmental trigger in the adopted country. Further prospective studies on homogenous migrant populations are needed to validate these observations, with a parallel arm for in-depth investigation of putative drivers. PMID:29391765

Epidemiology of inflammatory bowel disease in racial and ethnic migrant groups.

PubMed

Misra, Ravi; Faiz, Omar; Munkholm, Pia; Burisch, Johan; Arebi, Naila

2018-01-21

To summarise the current literature and define patterns of disease in migrant and racial groups. A structured key word search in Ovid Medline and EMBASE was undertaken in accordance with PRISMA guidelines. Studies on incidence, prevalence and disease phenotype of migrants and races compared with indigenous groups were eligible for inclusion. Thirty-three studies met the inclusion criteria. Individual studies showed significant differences in incidence, prevalence and disease phenotype between migrants or race and indigenous groups. Pooled analysis could only be undertaken for incidence studies on South Asians where there was significant heterogeneity between the studies [95% for ulcerative colitis (UC), 83% for Crohn's disease (CD)]. The difference between incidence rates was not significant with a rate ratio South Asian: Caucasian of 0.78 (95%CI: 0.22-2.78) for CD and 1.39 (95%CI: 0.84-2.32) for UC. South Asians showed consistently higher incidence and more extensive UC than the indigenous population in five countries. A similar pattern was observed for Hispanics in the United States. Bangladeshis and African Americans showed an increased risk of CD with perianal disease. This review suggests that migration and race influence the risk of developing inflammatory bowel disease. This may be due to different inherent responses upon exposure to an environmental trigger in the adopted country. Further prospective studies on homogenous migrant populations are needed to validate these observations, with a parallel arm for in-depth investigation of putative drivers.

Whip Use by Jockeys in a Sample of Australian Thoroughbred Races—An Observational Study

PubMed Central

McGreevy, Paul D.; Corken, Robert A.; Salvin, Hannah; Black, Celeste M.

2012-01-01

The use of whips by jockeys is an issue. The current study viewed opportunistic high-speed footage of 15 race finishes frame-by-frame to examine the outcomes of arm and wrist actions (n = 350) on 40 horses viewed from the left of the field. Any actions fully or partially obscured by infrastructure or other horses were removed from the database, leaving a total of 104 non-contact sweeps and 134 strikes. For all instances of arm actions that resulted in fully visible whip strikes behind the saddle (n = 109), the outcomes noted were area struck, percentage of unpadded section making contact, whether the seam made contact and whether a visible indentation was evident on impact. We also recorded use of clockwise or counter-clockwise arm action from each jockey's whip, whether the whip was held like a tennis racquet or a ski pole, whether the hind leg on the side of the impact was in stance or swing phase and whether the jockey's arm was seen traveling above shoulder height. The goal of the study was to characterize the area struck and the visual impact of whip use at the level of the horse. We measured the ways in which both padded and unpadded sections of the whip made impact. There was evidence of at least 28 examples, in 9 horses, of breaches of the whip rules (one seam contact, 13 contacts with the head, and 14 arm actions that rose above the height of the shoulder). The whip caused a visible indentation on 83% of impacts. The unpadded section of the whip made contact on 64% of impacts. The results call into question the ability of Stewards to effectively police the rules concerning whip use and, more importantly, challenge the notion that padding the distal section of whips completely safeguards horses from any possible whip-related pain. PMID:22442687

Sarcoporia polyspora (Basidiomycota, Polyporales): a rare wood-decay fungus newly recorded from South America

Treesearch

Daiana Bortoluzzi Baldoni; Beatriz Ortiz-Santana; Gilberto Coelho; Zaida I. Antoniolli; Rodrigo J.S. Jacques

2014-01-01

Brown-rot fungi degrade almost exclusively wood cellulosic materials participating in the, carbon cycle and soil formation of many forest regions, these are especially important on boreal and cultivated coniferous forests. These fungi and forests may have a common co-evolutionary history. Studying wood-inhabiting fungi in cultivated pine forests in Southern Brazil, we...

New frontiers in the study of human cultural and genetic evolution.

PubMed

Ross, Cody T; Richerson, Peter J

2014-12-01

In this review, we discuss the dynamic linkages between culture and the genetic evolution of the human species. We begin by briefly describing the framework of gene-culture coevolutionary (or dual-inheritance) models for human evolutionary change. Until recently, the literature on gene-culture coevolution was composed primarily of mathematical models and formalized theory describing the complex dynamics underlying human behavior, adaptation, and technological evolution, but had little empirical support concerning genetics. The rapid progress in the fields of molecular genetics and genomics, however, is now providing the kinds of data needed to produce rich empirical support for gene-culture coevolutionary models. We briefly outline how theoretical and methodological progress in genome sciences has provided ways for the strength of selection on genes to be evaluated, and then outline how evidence of selection on several key genes can be directly linked to human cultural practices. We then describe some exciting new directions in the empirical study of gene-culture coevolution, and conclude with a discussion of the role of gene-culture evolutionary models in the future integration of medical, biological, and social sciences. Copyright © 2014 Elsevier Ltd. All rights reserved.

Building toy models of proteins using coevolutionary information

NASA Astrophysics Data System (ADS)

Cheng, Ryan; Raghunathan, Mohit; Onuchic, Jose

2015-03-01

Recent developments in global statistical methodologies have advanced the analysis of large collections of protein sequences for coevolutionary information. Coevolution between amino acids in a protein arises from compensatory mutations that are needed to maintain the stability or function of a protein over the course of evolution. This gives rise to quantifiable correlations between amino acid positions within the multiple sequence alignment of a protein family. Here, we use Direct Coupling Analysis (DCA) to infer a Potts model Hamiltonian governing the correlated mutations in a protein family to obtain the sequence-dependent interaction energies of a toy protein model. We demonstrate that this methodology predicts residue-residue interaction energies that are consistent with experimental mutational changes in protein stabilities as well as other computational methodologies. Furthermore, we demonstrate with several examples that DCA could be used to construct a structure-based model that quantitatively agrees with experimental data on folding mechanisms. This work serves as a potential framework for generating models of proteins that are enriched by evolutionary data that can potentially be used to engineer key functional motions and interactions in protein systems. This research has been supported by the NSF INSPIRE award MCB-1241332 and by the CTBP sponsored by the NSF (Grant PHY-1427654).

Sustainable use of renewable resources in a stylized social-ecological network model under heterogeneous resource distribution

NASA Astrophysics Data System (ADS)

Barfuss, Wolfram; Donges, Jonathan F.; Wiedermann, Marc; Lucht, Wolfgang

2017-04-01

Human societies depend on the resources ecosystems provide. Particularly since the last century, human activities have transformed the relationship between nature and society at a global scale. We study this coevolutionary relationship by utilizing a stylized model of private resource use and social learning on an adaptive network. The latter process is based on two social key dynamics beyond economic paradigms: boundedly rational imitation of resource use strategies and homophily in the formation of social network ties. The private and logistically growing resources are harvested with either a sustainable (small) or non-sustainable (large) effort. We show that these social processes can have a profound influence on the environmental state, such as determining whether the private renewable resources collapse from overuse or not. Additionally, we demonstrate that heterogeneously distributed regional resource capacities shift the critical social parameters where this resource extraction system collapses. We make these points to argue that, in more advanced coevolutionary models of the planetary social-ecological system, such socio-cultural phenomena as well as regional resource heterogeneities should receive attention in addition to the processes represented in established Earth system and integrated assessment models.

Epidemiological, evolutionary and co-evolutionary implications of context-dependent parasitism

PubMed Central

Vale, Pedro F.; Wilson, Alastair J.; Best, Alex; Boots, Mike; Little, Tom J.

2013-01-01

Victims of infection are expected to suffer increasingly as parasite population growth increases. Yet, under some conditions, faster growing parasites do not appear to cause more damage and infections can be quite tolerable. We studied these conditions by assessing how the relationship between parasite population growth and host health is sensitive to environmental variation. In experimental infections of the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa we show how easily an interaction can shift from a severe interaction, i.e. when host fitness declines substantially with each unit of parasite growth, to a tolerable relationship by changing only simple environmental variables: temperature and food availability. We explored the evolutionary and epidemiological implications of such a shift by modelling pathogen evolution and disease spread under different levels of infection severity, and find that environmental shifts that promote tolerance ultimately result in populations harbouring more parasitized individuals. We also find that the opportunity for selection, as indicated by the variance around traits, varied considerably with the environmental treatment. Thus our results suggest two mechanisms that could underlie co-evolutionary hot- and coldspots: spatial variation in tolerance and spatial variation in the opportunity for selection. PMID:21460572

Epidemiological, evolutionary, and coevolutionary implications of context-dependent parasitism.

PubMed

Vale, Pedro F; Wilson, Alastair J; Best, Alex; Boots, Mike; Little, Tom J

2011-04-01

Abstract Victims of infection are expected to suffer increasingly as parasite population growth increases. Yet, under some conditions, faster-growing parasites do not appear to cause more damage, and infections can be quite tolerable. We studied these conditions by assessing how the relationship between parasite population growth and host health is sensitive to environmental variation. In experimental infections of the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa, we show how easily an interaction can shift from a severe interaction, that is, when host fitness declines substantially with each unit of parasite growth, to a tolerable relationship by changing only simple environmental variables: temperature and food availability. We explored the evolutionary and epidemiological implications of such a shift by modeling pathogen evolution and disease spread under different levels of infection severity and found that environmental shifts that promote tolerance ultimately result in populations harboring more parasitized individuals. We also find that the opportunity for selection, as indicated by the variance around traits, varied considerably with the environmental treatment. Thus, our results suggest two mechanisms that could underlie coevolutionary hotspots and coldspots: spatial variation in tolerance and spatial variation in the opportunity for selection.

US arms control obligations under the Non-Proliferation Treaty

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-06-27

Article VI of the 1968 Non-Proliferation Treaty (NPT) obligates the nuclear weapon states parties to the Treaty ''to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race, ... to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control.'' The preamble to the NPT recalls the 1963 Limited Test Ban Treaty ''determination ... to achieve the discontinuance of ... explosions.'' These provisions are interpreted by a majority of the non-nuclear weapon states parties to the Treaty as an obligation of the nuclear weapon states parties tomore » the Treaty to pursue a comprehensive test ban (CTB). However, a review of the history of the NPT negotiations and US ratification proceedings makes clear that the NPT imposes no legal obligation on the US to pursue a CTB. The US did not make a one-to-one correspondence between Article VI and any specific arms control measure; to the contrary, the US argued successfully that such a connection (to any specific measure) would be pernicious to the attempt to achieve agreement on the NPT. This interpretation, which was sustained through the negotiations and the ratification proceedings, still reflects the limits of the legal obligations the US has accepted. But, in the absence of progress on other arms control measures, which would relieve the pressure for a CTB, the majority interpretation creates political difficulties for the US and could threaten the NPT regime in the future. These problems highlight the need for the US to better defend its compliance with Article VI and to develop a long-term strategy that will permit necessary testing while assuring the survival of the NPT regime in effective form.« less

United States' arms control obligations under the NonProliferation Treaty

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-06-27

Article VI of the 1986 Non-Proliferation Treaty obligates the nuclear weapon states party to the Treaty ''to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race, ...to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control.'' The preamble to the NPT refers to the 1963 Limited Test Ban Treaty ''determination...to achieve the discontinuance of...explosions.'' These provisions are interpreted by many non-nuclear weapon states party to the NPT as an obligation of the nuclear weapon states party to the treaty to pursue a comprehensive test banmore » (CTB). However, a review of the history of the NPT negotiations and US ratification proceedings makes clear that Article VI imposes no legal obligation on the US to pursue a CTB. The United States did not make a one-to-one correspondence between Article VI and any specific arms control measure; to the contrary, the United States argued successfully that such a connection (to any specific measure) would be pernicious to the attempt to achieve agreement on the NPT. This interpretation held through the negotiations and ratification proceedings. However, a majority of NPT signatories assert that Article VI does indeed imply a commitment to a CTB. In the absence of progress on other arms control measures, which would relieve the pressure for a CTB, this interpretation creates a political problem for the US and could threaten the NPT regime in the future. These problems emphasize the need for the United States to more clearly explain its compliance with Article VI and to develop a long-term strategy that will permit necessary testing while assuring the survival of the NPT regime in effective form.« less

Validation of Heart Failure Events in the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) Participants Assigned to Doxazosin and Chlorthalidone

PubMed Central

Piller, Linda B; Davis, Barry R; Cutler, Jeffrey A; Cushman, William C; Wright, Jackson T; Williamson, Jeff D; Leenen, Frans HH; Einhorn, Paula T; Randall, Otelio S; Golden, John S; Haywood, L Julian

2002-01-01

Background The Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) is a randomized, double-blind, active-controlled trial designed to compare the rate of coronary heart disease events in high-risk hypertensive participants initially randomized to a diuretic (chlorthalidone) versus each of three alternative antihypertensive drugs: alpha-adrenergic blocker (doxazosin), ACE-inhibitor (lisinopril), and calcium-channel blocker (amlodipine). Combined cardiovascular disease risk was significantly increased in the doxazosin arm compared to the chlorthalidone arm (RR 1.25; 95% CI, 1.17–1.33; P < .001), with a doubling of heart failure (fatal, hospitalized, or non-hospitalized but treated) (RR 2.04; 95% CI, 1.79–2.32; P < .001). Questions about heart failure diagnostic criteria led to steps to validate these events further. Methods and Results Baseline characteristics (age, race, sex, blood pressure) did not differ significantly between treatment groups (P < .05) for participants with heart failure events. Post-event pharmacologic management was similar in both groups and generally conformed to accepted heart failure therapy. Central review of a small sample of cases showed high adherence to ALLHAT heart failure criteria. Of 105 participants with quantitative ejection fraction measurements provided, (67% by echocardiogram, 31% by catheterization), 29/46 (63%) from the chlorthalidone group and 41/59 (70%) from the doxazosin group were at or below 40%. Two-year heart failure case-fatalities (22% and 19% in the doxazosin and chlorthalidone groups, respectively) were as expected and did not differ significantly (RR 0.96; 95% CI, 0.67–1.38; P = 0.83). Conclusion Results of the validation process supported findings of increased heart failure in the ALLHAT doxazosin treatment arm compared to the chlorthalidone treatment arm. PMID:12459039

CATS Installed on ISS

NASA Image and Video Library

2017-12-08

On Jan. 22, 2015, robotic flight controllers successfully installed NASA’s Cloud Aerosol Transport System (CATS) onboard the International Space Station. CATS will collect data about clouds, volcanic ash plumes and tiny airborne particles that can help improve our understanding of aerosol and cloud interactions, and improve the accuracy of climate change models. CATS had been mounted inside the SpaceX Dragon cargo craft’s unpressurized trunk since it docked at the station on Jan. 12. Ground controllers at NASA’s Johnson Space Center in Houston, Texas, used one of the space station’s robotic arms, called the Special Purpose Dexterous Manipulator, to extract the instrument from the capsule. The NASA-controlled arm passed the instrument to a second robotic arm— like passing a baton in a relay race. This second arm, called the Japanese Experiment Module Remote Manipulator System, is controlled by the Japanese Aerospace Exploration Agency. The Japanese-controlled arm installed the instrument to the Space Station’s Japanese Experiment Module, making CATS the first NASA-developed payload to fly on the Japanese module. CATS is a lidar remote-sensing instrument designed to last from six months to three years. It is specifically intended to demonstrate a low-cost, streamlined approach to developing science payloads on the space station. CATS launched aboard the SpaceX Dragon spacecraft on Jan. 10 at Cape Canaveral Air Force Station in Florida. To learn more about the impact of CATS data, visit: www.nasa.gov/cats/ NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Systems of support to increase colorectal cancer screening and follow-up rates (SOS): design, challenges, and baseline characteristics of trial participants.

PubMed

Green, Beverly B; Wang, C Y; Horner, Kathryn; Catz, Sheryl; Meenan, Richard T; Vernon, Sally W; Carrell, David; Chubak, Jessica; Ko, Cynthia; Laing, Sharon; Bogart, Andy

2010-11-01

Screening decreases colorectal cancer (CRC) morbidity and mortality, yet remains underutilized. Screening breakdowns arise from lack of uptake and failure to follow-up after a positive screening test. Systems of support to increase colorectal cancer screening and follow-up (SOS) is a randomized trial designed to increase: (1) CRC screening and (2) follow-up of positive screening tests. The Chronic Care Model and the Preventive Health Model inform study design. The setting is a large nonprofit healthcare organization. In part-1 study, patients age 50-75 due for CRC screening are randomized to one of 4 study conditions. Arm 1 receives usual care. Arm 2 receives automated support (mailed information about screening choices and fecal occult blood tests (FOBT)). Arm 3 receives automated and assisted support (a medical assistant telephone call). Arm 4 receives automated, assisted, and care management support (a registered nurse provides behavioral activation and coordination of care). In part-2, study patients with a positive FOBT or adenomas on flexible sigmoidoscopy are randomized to receive either usual care or nurse care management. Primary outcomes are: 1) the proportion with CRC screening, 2) the proportion with a complete diagnostic evaluation after a positive screening test. We sent recruitment letters to 15,414 patients and 4675 were randomized. Randomly assigned treatment groups were similar in age, sex, race, education, self-reported health, and CRC screening history. We will determine the effectiveness and cost effectiveness of stepped increases in systems of support to increase CRC screening and follow-up after a positive screening test over 2years. Copyright © 2010 Elsevier Inc. All rights reserved.

Longitudinal changes in menopausal symptoms comparing women randomized to low-dose oral conjugated estrogens or transdermal estradiol plus micronized progesterone versus placebo: the Kronos Early Estrogen Prevention Study.

PubMed

Santoro, Nanette; Allshouse, Amanda; Neal-Perry, Genevieve; Pal, Lubna; Lobo, Rogerio A; Naftolin, Frederick; Black, Dennis M; Brinton, Eliot A; Budoff, Matthew J; Cedars, Marcelle I; Dowling, N Maritza; Dunn, Mary; Gleason, Carey E; Hodis, Howard N; Isaac, Barbara; Magnani, Maureen; Manson, JoAnn E; Miller, Virginia M; Taylor, Hugh S; Wharton, Whitney; Wolff, Erin; Zepeda, Viola; Harman, S Mitchell

2017-03-01

The objective of the present study was to compare the efficacy of two forms of menopausal hormone therapy in alleviating vasomotor symptoms, insomnia, and irritability in early postmenopausal women during 4 years. A total of 727 women, aged 42 to 58, within 3 years of their final menstrual period, were randomized to receive oral conjugated estrogens (o-CEE) 0.45 mg (n = 230) or transdermal estradiol (t-E2) 50 μg (n = 225; both with micronized progesterone 200 mg for 12 d each mo), or placebos (PBOs; n = 275). Menopausal symptoms were recorded at screening and at 6, 12, 24, 36, and 48 months postrandomization. Differences in proportions of women with symptoms at baseline and at each follow-up time point were compared by treatment arm using exact χ tests in an intent-to-treat analysis. Differences in treatment effect by race/ethnicity and body mass index were tested using generalized linear mixed effects modeling. Moderate to severe hot flashes (from 44% at baseline to 28.3% for PBO, 7.4% for t-E2, and 4.2% for o-CEE) and night sweats (from 35% at baseline to 19% for PBO, 5.3% for t-E2, and 4.7% for o-CEE) were reduced significantly by 6 months in women randomized to either active hormone compared with PBO (P < 0.001 for both symptoms), with no significant differences between the active treatment arms. Insomnia and irritability decreased from baseline to 6 months postrandomization in all groups. There was an intermittent reduction in insomnia in both active treatment arms versus PBO, with o-CEE being more effective than PBO at 36 and 48 months (P = 0.002 and 0.05) and t-E2 being more effective than PBO at 48 months (P = 0.004). Neither hormone treatment significantly affected irritability compared with PBO. Symptom relief for active treatment versus PBO was not significantly modified by body mass index or race/ethnicity. Recently postmenopausal women had similar and substantial reductions in hot flashes and night sweats with lower-than-conventional doses of oral or transdermal estrogen. These reductions were sustained during 4 years. Insomnia was intermittently reduced compared with PBO for both hormone regimens.

Longitudinal Changes in Menopausal Symptoms Comparing Women Randomized to Low-Dose Oral Conjugated Estrogens or Transdermal Estradiol Plus Micronized Progesterone Versus Placebo: the Kronos Early Estrogen Prevention Study (KEEPS)

PubMed Central

Santoro, Nanette; Allshouse, Amanda; Neal-Perry, Genevieve; Pal, Lubna; Lobo, Rogerio A.; Naftolin, Frederick; Black, Dennis M.; Brinton, Eliot A.; Budoff, Matthew J.; Cedars, Marcelle I.; Dowling, N. Maritza; Dunn, Mary; Gleason, Carey E.; Hodis, Howard N.; Isaac, Barbara; Magnani, Maureen; Manson, JoAnn E.; Miller, Virginia M.; Taylor, Hugh S.; Wharton, Whitney; Wolff, Erin; Zepeda, Viola; Harman, S. Mitchell

2016-01-01

Objective To compare the efficacy of two forms of menopausal hormone therapy in alleviating vasomotor symptoms, insomnia, and irritability in early menopausal women over four years. Methods 727 women, aged 42–58, within three years of their final menstrual period were randomized to receive oral conjugated estrogens (o-CEE) 0.45 mg (n=230) or transdermal estradiol (t-E2) 50mcg (n=225; both with micronized progesterone 200mg for 12 days each month), or placebos (PBO; n=275). Menopausal symptoms were recorded at screening and at 6, 12, 24, 36 and 48 months post-randomization. Differences in proportions of women with symptoms at baseline and at each followup timepoint were compared by treatment arm using exact chi-square tests in an intent-to-treat (ITT) analysis. Differences in treatment effect by race/ethnicity and body mass index (BMI) were tested using generalized linear mixed effects modeling. Results Moderate-to-severe hot flashes (from 44% at baseline to 28.3% for PBO, 7.4% for t-E2 and 4.2% for o-CEE) and night sweats (from 35% at baseline to 19% for PBO, 5.3% for t-E2 and 4.7% for o-CEE) were reduced significantly by 6 months in women randomized to either active hormone compared to PBO (P<0.001 for both symptoms), with no significant differences between the active treatment arms. Insomnia and irritability decreased from baseline to 6 months post randomization in all groups. There was an intermittent reduction in insomnia in both active treatment arms vs PBO, with o-CEE more effective than PBO at 36 and 48 months (p=0.002mad 0.05) and t-E2 more effective than PBO at 48 months (p=0.004). Neither hormone treatment significantly affected irritability compared to PBO. Symptom relief for active treatment vs PBO was not significantly modified by BMI or race/ethnicity. Conclusions Recently-menopausal women had similar and substantial reductions in hot flashes and night sweats with lower than conventional doses of oral or transdermal estrogen. These reductions were sustained over 4 years. Insomnia was intermittently reduced compared to placebo for both hormone regimens. PMID:27779568

Personal best time and training volume, not anthropometry, is related to race performance in the 'Swiss Bike Masters' mountain bike ultramarathon.

PubMed

Knechtle, Beat; Knechtle, Patrizia; Rosemann, Thomas; Senn, Oliver

2011-05-01

We investigated in 73 male ultraendurance mountain bikers, with (mean and SD) age 39.1 (8.6) years, weight 74.4 (8.3) kg, height 1.78 (0.07) m, and a body mass index of 23.3 (1.9) kg·m⁻², whether variables of anthropometry, training, or prerace experience were associated with race time using bi and multivariate analysis. Our investigation was conducted at the "Swiss Bike Masters," which covers a distance of 120 km and an altitude of 5,000 m. In the bivariate analysis, body mass index (r = 0.29), circumference of upper arm (r = 0.28), sum of upper body skinfolds (r = 0.38), sum of lower body skinfolds (r = 0.25), sum of 8 skinfolds (r = 0.36), percent body fat (r = 0.41), total cycling kilometers per year (r = -0.47), yearly volume in both mountain bike (r = -0.33) and road cycling (r = -0.52), number of training units per week (r = -0.48), distance per unit in road cycling (r = -0.33), average speed during training in road cycling (r = -0.33), and personal best time in the "Swiss Bike Masters"(r = 0.67) were related to race time. In the multiple linear regression analysis, personal best time in the "Swiss Bike Masters" (p = 0.000), total yearly cycling kilometers (p = 0.004), and yearly training kilometers in road cycling (p = 0.017) were related to race time. When the personal best time was the dependent variable in a separate regression model, total yearly cycling kilometers (p = 0.002) remained the single predictor variable. We concluded that finishing a particular mountain bike ultramarathon does not seem to require a special anthropometry but rather a specific skill and experience for this selective kind of race coupled with a high training volume. For practical use, we concluded that successful athletes in a mountain bike ultramarathon, in a special environment and using sophisticated equipment, need prerace experience coupled with high training volume, rather than any special anthropometry.

Identification of New Resistance Loci to African Stem Rust Race TTKSK in Tetraploid Wheats Based on Linkage and Genome-Wide Association Mapping.

PubMed

Laidò, Giovanni; Panio, Giosuè; Marone, Daniela; Russo, Maria A; Ficco, Donatella B M; Giovanniello, Valentina; Cattivelli, Luigi; Steffenson, Brian; de Vita, Pasquale; Mastrangelo, Anna M

2015-01-01

Stem rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn. (Pgt), is one of the most destructive diseases of wheat. Races of the pathogen in the "Ug99 lineage" are of international concern due to their virulence for widely used stem rust resistance genes and their spread throughout Africa. Disease resistant cultivars provide one of the best means for controlling stem rust. To identify quantitative trait loci (QTL) conferring resistance to African stem rust race TTKSK at the seedling stage, we evaluated an association mapping (AM) panel consisting of 230 tetraploid wheat accessions under greenhouse conditions. A high level of phenotypic variation was observed in response to race TTKSK in the AM panel, allowing for genome-wide association mapping of resistance QTL in wild, landrace, and cultivated tetraploid wheats. Thirty-five resistance QTL were identified on all chromosomes, and seventeen are of particular interest as identified by multiple associations. Many of the identified resistance loci were coincident with previously identified rust resistance genes; however, nine on chromosomes 1AL, 2AL, 4AL, 5BL, and 7BS may be novel. To validate AM results, a biparental population of 146 recombinant inbred lines was also considered, which derived from a cross between the resistant cultivar "Cirillo" and susceptible "Neodur." The stem rust resistance of Cirillo was conferred by a single gene on the distal region of chromosome arm 6AL in an interval map coincident with the resistance gene Sr13, and confirmed one of the resistance loci identified by AM. A search for candidate resistance genes was carried out in the regions where QTL were identified, and many of them corresponded to NBS-LRR genes and protein kinases with LRR domains. The results obtained in the present study are of great interest as a high level of genetic variability for resistance to race TTKSK was described in a germplasm panel comprising most of the tetraploid wheat sub-species.

Shaping Physiological Indices, Swimming Technique, and Their Influence on 200m Breaststroke Race in Young Swimmers

PubMed Central

Strzala, Marek; Stanula, Arkadiusz; Głab, Grzegorz; Glodzik, Jacek; Ostrowski, Andrzej; Kaca, Marcin; Nosiadek, Leszek

2015-01-01

The aim of this study was to investigate somatic properties and physiological capacity, and analyze kinematic parameters in the 200 m breaststroke swimming race. Twenty-seven male swimmers participated in the study. They were 15.7±1.98 years old. Their average height was 1.80 ± 0.02 m and lean body mass (LBM) was 62.45 ± 8.29 kg. Physiological exercise capacity was measured in two separate 90 sec. all-out tests, one for the arms and second for legs. During the tests total work of arm cranking (TWAR) and cycling (TWLG) as well as peak of VO2 for arm (VO2peakAR) and leg (VO2peakLG) were measured. The underwater swimmers body movements were recorded during the all-out swimming 200m breaststroke speed test using an underwater camera installed on a portable trolley. The swimming kinematic parameters and propulsive or non-propulsive movement phases of the arms and legs as well as average speed (V200), surface speed (V200surface) and swimming speed in turn zones (V200turns) were extracted. V200surface was significantly related to the percentage of leg propulsion and was shown to have large effect on VO2peakLG in the Cohen analysis. V200turns depended significantly on the indicators of physiological performance and body structure: TWAR, VO2peak LG and LBM, LBM, which in turn strongly determined the measured results of TWAR, TWLG, VO2peakAR and VO2peakLG. The V200turns and V200surface were strongly associated with V200, 0.92, p < 0.001 and 0.91, p < 0.001 respectively. In each lap of the 200m swimming there was an increased percentage of propulsion of limb movement observed simultaneously with a reduction in the gliding phase in the breaststroke cycles. Key points This study investigated the influence of the selected indicators of somatic properties and physiological capacity as well kinematic and coordination parameters on breaststroke swimming. In this observations the body’s functional capacity have an important impact on achieving good breaststroke swimming results, the V200 was moderately associated on VO2peakLG, moreover, separate V200turns depended with VO2peakLG and on LBM and TWAR. The speed of surface breaststroke swimming - V200surface similarly as V200turns had a very strong influence on the end result of V200 , 0.91, p<0.001 and 0.92, p<0.001 respectively. The ability to swim fast on the surface (V200surface) was positively and significantly associated with the percentage time of propulsion generation -LP in the breaststroke cycle. PMID:25729298

Buried treasure: evolutionary perspectives on microbial iron piracy

PubMed Central

Barber, Matthew F.; Elde, Nels C.

2015-01-01

Host-pathogen interactions provide valuable systems for the study of evolutionary genetics and natural selection. The sequestration of essential iron has emerged as a critical innate defense system termed nutritional immunity, leading pathogens to evolve mechanisms of `iron piracy' to scavenge this metal from host proteins. This battle for iron carries numerous consequences not only for host-pathogen evolution, but also microbial community interactions. Here we highlight recent and potential future areas of investigation on the evolutionary implications of microbial iron piracy in relation to molecular arms races, host range, competition, and virulence. Applying evolutionary genetic approaches to the study of microbial iron acquisition could also provide new inroads for understanding and combating infectious disease. PMID:26431675

The Non-Proliferation Treaty review: An American perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunn, L.A.

1985-01-01

Since the entry into the force in March 1970, the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) has played a central part in this decades-long endeavor. The Treaty's specific undertakings have been carefully crafted to serve its three major objectives. The first, which was the driving force behind the initial push for the NPT, is to prevent the further spread of nuclear weapons. The second is to foster peaceful nuclear cooperation under safeguards. The third objective, added during the multilateral negotiation of the NPT, is to encourage good faith negotiations to end the nuclear arms race with a viewmore » to general and complete disarmament.« less