Science.gov

Sample records for problematic ant taxon

  1. Species delimitation: A case study in a problematic ant taxon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species delimitation has been invigorated as a discipline in systematics by an influx of new character sets, analytical methods, and conceptual advances. We use genetic data from 68 markers, combined with distributional, bioclimatic, and coloration information, to distinguish evolutionarily indepe...

  2. Large-scale phylogenomic analysis reveals the phylogenetic position of the problematic taxon Protocruzia and unravels the deep phylogenetic affinities of the ciliate lineages.

    PubMed

    Gentekaki, E; Kolisko, M; Boscaro, V; Bright, K J; Dini, F; Di Giuseppe, G; Gong, Y; Miceli, C; Modeo, L; Molestina, R E; Petroni, G; Pucciarelli, S; Roger, A J; Strom, S L; Lynn, D H

    2014-09-01

    The Ciliophora is one of the most studied protist lineages because of its important ecological role in the microbial loop. While there is an abundance of molecular data for many ciliate groups, it is commonly limited to the 18S ribosomal RNA locus. There is a paucity of data when it comes to availability of protein-coding genes especially for taxa that do not belong to the class Oligohymenophorea. To address this gap, we have sequenced EST libraries for 11 ciliate species. A supermatrix was constructed for phylogenomic analysis based on 158 genes and 42,158 characters and included 16 ciliates, four dinoflagellates and nine apicomplexans. This is the first multigene-based analysis focusing on the phylum Ciliophora. Our analyses reveal two robust superclades within the Intramacronucleata; one composed of the classes Spirotrichea, Armophorea and Litostomatea (SAL) and another with Colpodea and Oligohymenophorea. Furthermore, we provide corroborative evidence for removing the ambiguous taxon Protocruzia from the class Spirotrichea and placing it as incertae sedis in the phylum Ciliophora. PMID:24814356

  3. Policy Problematization

    ERIC Educational Resources Information Center

    Webb, P. Taylor

    2014-01-01

    This article places Michel Foucault's concept of "problematization" in relation to educational policy research. My goal is to examine a key assumption of policy related to "solving problems" through such technologies. I discuss the potential problematization has to alter conceptions of policy research; and, through this…

  4. Honey Ants.

    ERIC Educational Resources Information Center

    Conway, John R.

    1984-01-01

    Provides background information on honey ants. These ants are found in dry or desert regions of North America, Africa, and Australia. Also provides a list of activities using local species of ants. (JN)

  5. Cross-taxon congruence and environmental conditions

    PubMed Central

    2010-01-01

    Background Diversity patterns of different taxa typically covary in space, a phenomenon called cross-taxon congruence. This pattern has been explained by the effect of one taxon diversity on taxon diversity, shared biogeographic histories of different taxa, and/or common responses to environmental conditions. A meta-analysis of the association between environment and diversity patterns found that in 83 out of 85 studies, more than 60% of the spatial variability in species richness was related to variables representing energy, water or their interaction. The role of the environment determining taxa diversity patterns leads us to hypothesize that this would explain the observed cross-taxon congruence. However, recent analyses reported the persistence of cross-taxon congruence when environmental effect was statistically removed. Here we evaluate this hypothesis, analyzing the cross-taxon congruence between birds and mammals in the Brazilian Cerrado, and assess the environmental role on the spatial covariation in diversity patterns. Results We found a positive association between avian and mammal richness and a positive latitudinal trend for both groups in the Brazilian Cerrado. Regression analyses indicated an effect of latitude, PET, and mean temperature over both biological groups. In addition, we show that NDVI was only associated with avian diversity; while the annual relative humidity, was only correlated with mammal diversity. We determined the environmental effects on diversity in a path analysis that accounted for 73% and 76% of the spatial variation in avian and mammal richness. However, an association between avian and mammal diversity remains significant. Indeed, the importance of this link between bird and mammal diversity was also supported by a significant association between birds and mammal spatial autoregressive model residuals. Conclusion Our study corroborates the main role of environmental conditions on diversity patterns, but suggests that other

  6. Oxymonads are closely related to the excavate taxon Trimastix.

    PubMed

    Dacks, J B; Silberman, J D; Simpson, A G; Moriya, S; Kudo, T; Ohkuma, M; Redfield, R J

    2001-06-01

    Despite intensive study in recent years, large-scale eukaryote phylogeny remains poorly resolved. This is particularly problematic among the groups considered to be potential early branches. In many recent systematic schemes for early eukaryotic evolution, the amitochondriate protists oxymonads and Trimastix have figured prominently, having been suggested as members of many of the putative deep-branching higher taxa. However, they have never before been proposed as close relatives of each other. We amplified, cloned, and sequenced small-subunit ribosomal RNA genes from the oxymonad Pyrsonympha and from several Trimastix isolates. Rigorous phylogenetic analyses indicate that these two protist groups are sister taxa and are not clearly related to any currently established eukaryotic lineages. This surprising result has important implications for our understanding of cellular evolution and high-level eukaryotic phylogeny. Given that Trimastix contains small, electron-dense bodies strongly suspected to be derived mitochondria, this study constitutes the best evidence to date that oxymonads are not primitively amitochondriate. Instead, Trimastix and oxymonads may be useful organisms for investigations into the evolution of the secondary amitochondriate condition. All higher taxa involving either oxymonads or Trimastix may require modification or abandonment. Affected groups include four contemporary taxa given the rank of phylum (Metamonada, Loukozoa, Trichozoa, Percolozoa), and the informal excavate taxa. A new "phylum-level" taxon may be warranted for oxymonads and Trimastix. PMID:11371592

  7. Foundational issues concerning taxa and taxon names.

    PubMed

    Ereshefsky, Marc

    2007-04-01

    In a series of articles, Rieppel (2005, Biol. Philos. 20:465-487; 2006a, Cladistics 22:186-197; 2006b, Systematist 26:5-9), Keller et al. (2003, Bot. Rev. 69:93-110), and Nixon and Carpenter (2000, Cladistics 16:298-318) criticize the philosophical foundations of the PhyloCode. They argue that species and higher taxa are not individuals, and they reject the view that taxon names are rigid designators. Furthermore, they charge supporters of the individuality thesis and rigid designator theory with assuming essentialism, committing logical inconsistencies, and offering proposals that render taxonomy untestable. These charges are unsound. Such charges turn on confusions over rigid designator theory and the distinction between kinds and individuals. In addition, Rieppel's, Keller et al.'s, and Nixon and Carpenter's proposed alternatives are no better and have their own problems. The individuality thesis and rigid designator theory should not be quickly abandoned. PMID:17464884

  8. Interaction between Locale and Taxon Strategies in Human Spatial Learning

    ERIC Educational Resources Information Center

    Redhead, Edward S.; Hamilton, Derek A.

    2007-01-01

    Three computer-based experiments which tested human participants in a non-immersive virtual watermaze task sought to determine factors which dictate whether the presence of a visual platform disrupts locale learning and taxon learning. In Experiment 1, the visible platform disrupted locale but not taxon learning based on viewpoint-independent and…

  9. The Ants Have It!

    ERIC Educational Resources Information Center

    Daugherty, Belinda

    2001-01-01

    Uses the GEMS guide, "Ants at Home Underground", to explore the life of ants and teach about them in a classroom setting. The activity applies students' knowledge of ants and students learn about ant colonies, what ants eat, and how they live. (SAH)

  10. Gamergates in the Australian ant subfamily Myrmeciinae

    NASA Astrophysics Data System (ADS)

    Dietemann, Vincent; Peeters, Christian; Hölldobler, Bert

    2004-09-01

    Ant workers can mate and reproduce in a few hundreds of species belonging to the phylogenetically basal poneromorph subfamilies (sensu Bolton 2003). We report the first occurrence of gamergates (i.e. mated reproductive workers) in a myrmeciomorph subfamily. In a colony of Myrmecia pyriformis that was collected without a queen, workers continued to be produced over a period of 3 years in the laboratory. Behavioural observations and ovarian dissections indicated that three workers were mated and produced the diploid offspring. The Myrmeciinae are thus another taxon in which the selective benefits of sexual reproduction by workers can be investigated.

  11. Ant nebula

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A new Hubble Space Telescope image of a celestial object called the Ant Nebula may shed new light on the future demise of our Sun. The image is available at http://www.jpl.nasa.gov/pictures/wfpc .

    The nebula, imaged on July 20, 1997, and June 30, 1998, by Hubble's Wide Field and Planetary Camera 2, was observed by Drs. Raghvendra Sahai and John Trauger of NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Bruce Balick of the University of Washington in Seattle; and Vincent Icke of Leiden University in the Netherlands. JPL designed and built the camera.

    The Ant Nebula, whose technical name is Mz3, resembles the head and thorax of an ant when observed with ground-based telescopes. The new Hubble image, with 10 times the resolution revealing 100 times more detail, shows the 'ant's' body as a pair of fiery lobes protruding from a dying, Sun- like star. The Ant Nebula is located between 3,000 and 6,000 light years from Earth in the southern constellation Norma.

    The image challenges old ideas about what happens to dying stars. This observation, along with other pictures of various remnants of dying stars called planetary nebulae, shows that our Sun's fate will probably be much more interesting, complex and dramatic than astronomers previously believed.

    Although the ejection of gas from the dying star in the Ant Nebula is violent, it does not show the chaos one might expect from an ordinary explosion, but instead shows symmetrical patterns. One possibility is that the central star has a closely orbiting companion whose gravitational tidal forces shape the outflowing gas. A second possibility is that as the dying star spins, its strong magnetic fields are wound up into complex shapes like spaghetti in an eggbeater. Electrically charged winds, much like those in our Sun's solar wind but millions of times denser and moving at speeds up to 1,000 kilometers per second (more than 600 miles per second) from the star, follow the twisted field lines on their way

  12. Improved phylogenomic taxon sampling noticeably affects nonbilaterian relationships.

    PubMed

    Pick, K S; Philippe, H; Schreiber, F; Erpenbeck, D; Jackson, D J; Wrede, P; Wiens, M; Alié, A; Morgenstern, B; Manuel, M; Wörheide, G

    2010-09-01

    Despite expanding data sets and advances in phylogenomic methods, deep-level metazoan relationships remain highly controversial. Recent phylogenomic analyses depart from classical concepts in recovering ctenophores as the earliest branching metazoan taxon and propose a sister-group relationship between sponges and cnidarians (e.g., Dunn CW, Hejnol A, Matus DQ, et al. (18 co-authors). 2008. Broad phylogenomic sampling improves resolution of the animal tree of life. Nature 452:745-749). Here, we argue that these results are artifacts stemming from insufficient taxon sampling and long-branch attraction (LBA). By increasing taxon sampling from previously unsampled nonbilaterians and using an identical gene set to that reported by Dunn et al., we recover monophyletic Porifera as the sister group to all other Metazoa. This suggests that the basal position of the fast-evolving Ctenophora proposed by Dunn et al. was due to LBA and that broad taxon sampling is of fundamental importance to metazoan phylogenomic analyses. Additionally, saturation in the Dunn et al. character set is comparatively high, possibly contributing to the poor support for some nonbilaterian nodes. PMID:20378579

  13. Improved Phylogenomic Taxon Sampling Noticeably Affects Nonbilaterian Relationships

    PubMed Central

    Pick, K.S.; Philippe, H.; Schreiber, F.; Erpenbeck, D.; Jackson, D.J.; Wrede, P.; Wiens, M.; Alié, A.; Morgenstern, B.; Manuel, M.; Wörheide, G.

    2010-01-01

    Despite expanding data sets and advances in phylogenomic methods, deep-level metazoan relationships remain highly controversial. Recent phylogenomic analyses depart from classical concepts in recovering ctenophores as the earliest branching metazoan taxon and propose a sister-group relationship between sponges and cnidarians (e.g., Dunn CW, Hejnol A, Matus DQ, et al. (18 co-authors). 2008. Broad phylogenomic sampling improves resolution of the animal tree of life. Nature 452:745–749). Here, we argue that these results are artifacts stemming from insufficient taxon sampling and long-branch attraction (LBA). By increasing taxon sampling from previously unsampled nonbilaterians and using an identical gene set to that reported by Dunn et al., we recover monophyletic Porifera as the sister group to all other Metazoa. This suggests that the basal position of the fast-evolving Ctenophora proposed by Dunn et al. was due to LBA and that broad taxon sampling is of fundamental importance to metazoan phylogenomic analyses. Additionally, saturation in the Dunn et al. character set is comparatively high, possibly contributing to the poor support for some nonbilaterian nodes. PMID:20378579

  14. Taxonicity of anxiety sensitivity: an empirical test among youth.

    PubMed

    Bernstein, Amit; Zvolensky, Michael J; Weems, Carl; Stickle, Timothy; Leen-Feldner, Ellen W

    2005-09-01

    Taxometric coherent cut kinetic analyses were used to test the latent structure of anxiety sensitivity (AS) among 371 youth. Anxiety sensitivity was indexed by the 18-item Childhood Anxiety Sensitivity Index (CASI; Silverman et al., J. Clin. Child Psychol. (1991), 20, 162-168). Two sets of manifest indicators of AS were constructed using the CASI: (1) three item-parcel manifest indicators: disease concerns, unsteady concerns, and mental illness concerns; and (2) nine single-item indicators representing each of these three facets of AS. Results from standard and short-scale MAXCOV procedures, internal consistency tests, analyses of simulated Monte Carlo data, and MAMBAC external consistency tests indicated that the latent structure of anxiety sensitivity among youth was taxonic. Estimated base rate of the observed AS taxon ranged between 13.6 and 16.5%. The present findings are discussed in terms of theoretical implications for the study of AS and vulnerability for anxiety psychopathology. PMID:16005702

  15. Psychopathological factors associated with problematic alcohol and problematic Internet use in a sample of adolescents in Germany.

    PubMed

    Wartberg, Lutz; Brunner, Romuald; Kriston, Levente; Durkee, Tony; Parzer, Peter; Fischer-Waldschmidt, Gloria; Resch, Franz; Sarchiapone, Marco; Wasserman, Camilla; Hoven, Christina W; Carli, Vladimir; Wasserman, Danuta; Thomasius, Rainer; Kaess, Michael

    2016-06-30

    In Germany, high prevalence rates for problematic alcohol use and problematic Internet use in adolescents were reported. The objective of the present study was to identify psychopathological factors associated with these two behavior patterns. To our knowledge, this is the first investigation assessing psychopathological factors for both problematic alcohol and problematic Internet use in the same sample of adolescents. We surveyed a sample of 1444 adolescents in Germany regarding problematic alcohol use, problematic Internet use, psychopathology and psychological well-being. We conducted binary logistic regression analyses. 5.6% of the sample showed problematic alcohol use, 4.8% problematic Internet use, and 0.8% both problematic alcohol and problematic Internet use. Problematic alcohol use was higher in adolescents with problematic Internet use compared to those without problematic Internet use. Conduct problems and depressive symptoms were statistically significant associated with both problematic alcohol and problematic Internet use. Prosocial behavior was related to problematic Internet use. Male gender and less peer problems were associated with problematic alcohol use. For the first time associations between adolescent problematic alcohol and problematic Internet use due to common psychopathological factors were identified. However, in addition to shared factors, we found also specific psychopathological correlates associated with these two behavior patterns. PMID:27138817

  16. Forensic evaluation of problematic Internet use.

    PubMed

    Recupero, Patricia R

    2008-01-01

    Problematic Internet use appears to be a growing concern in many criminal and civil legal proceedings. Problems range from inappropriate personal use of the Internet in the workplace and excessive use of online games, pornography, and gambling, to cyberbullying among children and adolescents and numerous forms of criminal activity. Forensic psychiatric evaluations may help courts or other agencies to understand individual cases and to discern whether a psychiatric disability may be involved. Furthermore, the forensic psychiatrist may be asked to formulate a prognosis or to suggest which treatments may be helpful. Among the multiple underlying pathophysiologic mechanisms that explain problematic Internet use are: addiction, compulsion, impulse-control problems, and mood disorders. There is no definitive or standard treatment protocol for evaluation or treatment of problematic Internet use per se. A comprehensive evaluation should address the underlying psychopathology or personal problems that prompt or contribute to the problematic Internet use. This article suggests approaches that may help forensic psychiatrists to conduct a thorough evaluation with reasonable treatment recommendations. Different formulations of the problem and a discussion of DSM-IV factors are offered to provide starting points for the evaluation and to help psychiatrists to understand how problematic Internet use may relate to Axis I disorders or other factors. PMID:19092069

  17. Problematic Internet Usage and Immune Function.

    PubMed

    Reed, Phil; Vile, Rebecca; Osborne, Lisa A; Romano, Michela; Truzoli, Roberto

    2015-01-01

    Problematic internet use has been associated with a variety of psychological comorbidities, but it relationship with physical illness has not received the same degree of investigation. The current study surveyed 505 participants online, and asked about their levels of problematic internet usage (Internet Addiction Test), depression and anxiety (Hospital Anxiety and Depression Scales), social isolation (UCLA Loneliness Questionnaire), sleep problems (Pittsburgh Sleep Quality Index), and their current health - General Health Questionnaire (GHQ-28), and the Immune Function Questionnaire. The results demonstrated that around 30% of the sample displayed mild or worse levels of internet addiction, as measured by the IAT. Although there were differences in the purposes for which males and females used the internet, there were no differences in terms of levels of problematic usage between genders. The internet problems were strongly related to all of the other psychological variables such as depression, anxiety, social-isolation, and sleep problems. Internet addiction was also associated with reduced self-reported immune function, but not with the measure of general health (GHQ-28). This relationship between problematic internet use and reduced immune function was found to be independent of the impact of the co-morbidities. It is suggested that the negative relationship between level of problematic internet use and immune function may be mediated by levels of stress produced by such internet use, and subsequent sympathetic nervous activity, which related to immune-supressants, such as cortisol. PMID:26244339

  18. Problematic Internet Usage and Immune Function

    PubMed Central

    Reed, Phil; Vile, Rebecca; Osborne, Lisa A.; Romano, Michela; Truzoli, Roberto

    2015-01-01

    Problematic internet use has been associated with a variety of psychological comorbidities, but it relationship with physical illness has not received the same degree of investigation. The current study surveyed 505 participants online, and asked about their levels of problematic internet usage (Internet Addiction Test), depression and anxiety (Hospital Anxiety and Depression Scales), social isolation (UCLA Loneliness Questionnaire), sleep problems (Pittsburgh Sleep Quality Index), and their current health – General Health Questionnaire (GHQ-28), and the Immune Function Questionnaire. The results demonstrated that around 30% of the sample displayed mild or worse levels of internet addiction, as measured by the IAT. Although there were differences in the purposes for which males and females used the internet, there were no differences in terms of levels of problematic usage between genders. The internet problems were strongly related to all of the other psychological variables such as depression, anxiety, social-isolation, and sleep problems. Internet addiction was also associated with reduced self-reported immune function, but not with the measure of general health (GHQ-28). This relationship between problematic internet use and reduced immune function was found to be independent of the impact of the co-morbidities. It is suggested that the negative relationship between level of problematic internet use and immune function may be mediated by levels of stress produced by such internet use, and subsequent sympathetic nervous activity, which related to immune-supressants, such as cortisol. PMID:26244339

  19. The ant raft

    NASA Astrophysics Data System (ADS)

    Mlot, Nathan; Hu, David; Equabai, Solomon

    2009-11-01

    To survive floods, fire ants link their arms together to assemble a raft with their own bodies. Because ants are nearly as dense as water, this cooperative behavior requires that a portion of the ant colony must sacrifice itself by remaining underwater to support the colony's weight. Surprisingly, few ants drown during this process due to a striking metamorphosis of the raft: as we show using time-lapse photography, the raft morphs from a spherical to a pancake shape. This pancake configuration--a monolayer of floating ants supporting their dry counterparts--allows all ants to both breathe and remain united as a colony. Data is presented in the form of the dimensions and the rates of formation of the ant raft. We use the statics of small floating bodies to account for the equilibrium raft size as a function of the initial mass and density of the ants.

  20. Developing terrestrial, multi-taxon indices of biological integrity: An example from coastal sage scrub

    USGS Publications Warehouse

    Diffendorfer, J.E.; Fleming, G.M.; Duggan, J.M.; Chapman, R.E.; Rahn, M.E.; Mitrovich, M.J.; Fisher, R.N.

    2007-01-01

    We screened 351 species or genera for their response to disturbance in coastal sage scrub (CSS) to develop a 15-metric, 5-taxon Index of Biological Integrity (IBI). We collected data on ants, birds, herpetofauna, small mammals, and plants for two years on 46 sites established across a gradient of disturbance in three reserves. The gradient spanned relatively intact CSS with thick stands of shrubs, to former CSS stands type-converted to exotic grasses. ANOVAs and clustering analyses indicated the IBI could distinguish four levels of disturbance in CSS. General measures of community structure, such as richness, did not show changes across the gradient for most taxa, and responses of taxa across the gradient were varied and rarely correlated. However, turnover in species or genera across the gradient was common across all taxa as shrub-obligate life forms were replaced by those favoring grassy or disturbed habitats. Our data indicate index-based approaches based on data collected across disturbance gradients may outperform more traditional community level metrics when responses to anthropogenic influences are complex and vary across species. ?? 2007 Elsevier Ltd. All rights reserved.

  1. Polygyny and polyandry in small ant societies.

    PubMed

    Kellner, K; Trindl, A; Heinze, J; D'Ettorre, P

    2007-06-01

    Social insects, ants in particular, show considerable variation in queen number and mating frequency resulting in a wide range of social structures. The dynamics of reproductive conflicts in insect societies are directly connected to the colony kin structure, thus, the study of relatedness patterns is essential in order to understand the evolutionary resolution of these conflicts. We studied colony kin structure and mating frequencies in two closely related Neotropical ant species Pachycondyla inversa and Pachycondyla villosa. These represent interesting model systems because queens found new colonies cooperatively but, unlike many other ant species, they may still co-exist when the colony becomes mature (primary polygyny). By using five specific and highly variable microsatellite markers, we show that in both species queens usually mate with two or more males and that cofounding queens are always unrelated. Polygynous and polyandrous colonies are characterized by a high genetic diversity, with a mean relatedness coefficient among worker nestmates of 0.27 (+/- 0.03 SE) for P. inversa and 0.31 (+/- 0.05 SE) for P. villosa. However, relatedness among workers of the same matriline is high (0.60 +/- 0.03 in P. inversa, 0.62 +/- 0.08 in P. villosa) since males that mated with the same queen are on average closely related. Hence, we have found a new taxon in social Hymenoptera with high queen-mating frequencies and with intriguing mating and dispersal patterns of the sexuals. PMID:17561897

  2. Detecting Problematic Observer Offsets in Sparse Photometry

    NASA Astrophysics Data System (ADS)

    Calderwood, T.

    2014-06-01

    A heuristic method, based upon histogram analysis, is presented for detecting offsets pervasive enough to be symptoms of problematic observing technique or calibration. This method is illustrated by a study of scatter in AAVSO photoelectric photometry (PEP) for five well-observed variable stars.

  3. Detecting Problematic Observer Offsets in Sparse Photometry

    NASA Astrophysics Data System (ADS)

    Calderwood, Tom

    2014-05-01

    A heuristic method, based upon histogram analysis, is presented for detecting offsets pervasive enough to be symptoms of problematic observing technique or calibration. This method is illustrated by a study of scatter in AAVSO photoelectric photometry (PEP) for five well-observed variable stars.

  4. Persistence of Problematic Sexual Behaviors in Children

    ERIC Educational Resources Information Center

    Levesque, Mireille; Bigras, Marc; Pauze, Robert

    2012-01-01

    The purpose of this study was to identify personal and family predictors and correlates of persistence of problematic sexual behaviors (PSB) in children. Participants were the families of 49 children (ages 4-11 years) referred by Child Protective Services in 4 administrative districts of Quebec. Caregivers completed interviews and questionnaires…

  5. Relaxation/Covert Rehearsal for Problematic Children.

    ERIC Educational Resources Information Center

    Fling, Sheila; McKenzie, Patricia

    A study was conducted to determine whether group relaxation training combined with guided fantasy as a method of covert cognitive rehearsal would be more effective than story-listening or no special treatment in enabling "problematic" children to decrease muscle tension, activity level, and behavior problems and to increase academic performance…

  6. Problematic Internet use and physical health.

    PubMed

    Kelley, Kevin J; Gruber, Elon M

    2013-06-01

    Background and aims A considerable body of literature has emerged over the past two decades assessing the relationship between problematic or addictive use of the Internet and various indices of psychological well-being. Conversely, comparatively little research has assessed the relationship between problematic or addictive use of the Internet and one's physical health. Method The current study assesses this relationship using a sample of college students (N = 133) who responded online to two questionnaires: the Problematic Internet Use Questionnaire (PIUQ; Demetrovics, Szeredi&Rózsa, 2008) and the SF-36v2 Health Survey (Ware et al., 2008). Results The findings indicate that problematic Internet use is associated with poorer physical health. These results are consistent with other data that assessed the relationship between these two variables. Furthermore, this relationship supersedes the influence of the number of hours spent online per day. Conclusions The findings are discussed in terms of the limitations of the study design and conclusions that can be drawn from this preliminary empirical effort. PMID:26165930

  7. Problematic Internet Use: Perceptions of Addiction Counsellors

    ERIC Educational Resources Information Center

    Acier, Didier; Kern, Laurence

    2011-01-01

    Despite a growing number of publications on problematic Internet use (PIU), there is no consensus on the nature of the phenomenon, its constituent criteria, and its clinical threshold. This qualitative study examines the perceptions of addiction counsellors who have managed individuals with PIU in Quebec (Canada). Four focus groups were conducted…

  8. Lexical Choice: Towards Writing Problematic Word Lists.

    ERIC Educational Resources Information Center

    Zughoul, Muhammad Raji

    1991-01-01

    Quantitative and qualitative analysis of lexical choice errors made by native Arabic-speaking learners of English in written compositions indicated that first-language interference is a major variable in lexical choice. Results lend support to the development of problematic word lists to help learners adopt practical strategies for improving…

  9. Some 'ant'swers: Application of a layered barcode approach to problems in ant taxonomy.

    PubMed

    Paknia, Omid; Bergmann, Tjard; Hadrys, Heike

    2015-11-01

    DNA barcoding has emerged as a routine tool in modern taxonomy. Although straightforward, this approach faces new challenges, when applied to difficult situation such as defining cryptic biodiversity. Ants are prime examples for high degrees of cryptic biodiversity due to complex population differentiation, hybridization and speciation processes. Here, we test the DNA barcoding region, cytochrome c oxidase 1 and two supplementary markers, 28S ribosomal DNA and long-wavelength rhodopsin, commonly used in ant taxonomy, for their potential in a layered, character-based barcoding approach across different taxonomic levels. Furthermore, we assess performance of the character-based barcoding approach to determine cryptic species diversity in ants. We found (i) that the barcode potential of a specific genetic marker varied widely among taxonomic levels in ants; (ii) that application of a layered, character-based barcode for identification of specimens can be a solution to taxonomical challenging groups; (iii) that the character-based barcoding approach allows us to differentiate specimens even within locations based on pure characters. In summary, (layered) character-based barcoding offers a reliable alternative for problematic species identification in ants and can be used as a fast and cost-efficient approach to estimate presence, absence or frequency of cryptic species. PMID:25712507

  10. Ant- and Ant-Colony-Inspired ALife Visual Art.

    PubMed

    Greenfield, Gary; Machado, Penousal

    2015-01-01

    Ant- and ant-colony-inspired ALife art is characterized by the artistic exploration of the emerging collective behavior of computational agents, developed using ants as a metaphor. We present a chronology that documents the emergence and history of such visual art, contextualize ant- and ant-colony-inspired art within generative art practices, and consider how it relates to other ALife art. We survey many of the algorithms that artists have used in this genre, address some of their aims, and explore the relationships between ant- and ant-colony-inspired art and research on ant and ant colony behavior. PMID:26280070

  11. Taxonicity of anxiety sensitivity: a multi-national analysis.

    PubMed

    Bernstein, Amit; Zvolensky, Michael J; Kotov, Roman; Arrindell, Willem A; Taylor, Steven; Sandin, Bonifacio; Cox, Brian J; Stewart, Sherry H; Bouvard, Martine; Cardenas, Samuel Jurado; Eifert, Georg H; Schmidt, Norman B

    2006-01-01

    Taxometric coherent cut kinetic analyses were used to test the latent structure of anxiety sensitivity in samples from North America (Canada and United States of America), France, Mexico, Spain, and The Netherlands (total n = 2741). Anxiety sensitivity was indexed by the 36-item Anxiety Sensitivity Index--Revised (ASI-R; [J. Anxiety Disord. 12(5) (1998) 463]). Four manifest indicators of anxiety sensitivity were constructed using the ASI-R: fear of cardiovascular symptoms, fear of respiratory symptoms, fear of publicly observable anxiety reactions, and fear of mental incapacitation. Results from MAXCOV-HITMAX, internal consistency tests, analyses of simulated Monte Carlo data, and a MAMBAC external consistency test indicated that the latent structure of anxiety sensitivity was taxonic in each of the samples. The estimated base rate of the anxiety sensitivity taxon differed slightly between nations, ranging from 11.5 to 21.5%. In general, the four ASI-R based manifest indicators showed high levels of validity. Results are discussed in relation to the conceptual understanding of anxiety sensitivity, with specific emphasis on theoretical refinement of the construct. PMID:16325111

  12. Acoustic communication by ants

    NASA Astrophysics Data System (ADS)

    Hickling, Robert

    2002-05-01

    Many ant species communicate acoustically by stridulating, i.e., running a scraper over a washboard-like set of ridges. Ants appear to be insensitive to airborne sound. Consequently, myrmecologists have concluded that the stridulatory signals are transmitted through the substrate. This has tended to diminish the importance of acoustic communication, and it is currently believed that ant communication is based almost exclusively on pheromones, with acoustic communication assigned an almost nonexistent role. However, it can be shown that acoustic communication between ants is effective only if the medium is air and not the substrate. How, then, is it possible for ants to appear deaf to airborne sound and yet communicate through the air? An explanation is provided in a paper [R. Hickling and R. L. Brown, ``Analysis of acoustic communication by ants,'' J. Acoust. Soc. Am. 108, 1920-1929 (2000)]. Ants are small relative to the wavelengths they generate. Hence, they create a near field, which is characterized by a major increase in sound velocity (particle velocity of sound) in the vicinity of the source. Hair sensilla on the ants' antennae respond to sound velocity. Thus, ants are able to detect near-field sound from other ants and to exclude extraneous airborne sound.

  13. Assessing the Value of DNA Barcodes for Molecular Phylogenetics: Effect of Increased Taxon Sampling in Lepidoptera

    PubMed Central

    Wilson, John James

    2011-01-01

    Background A common perception is that DNA barcode datamatrices have limited phylogenetic signal due to the small number of characters available per taxon. However, another school of thought suggests that the massively increased taxon sampling afforded through the use of DNA barcodes may considerably increase the phylogenetic signal present in a datamatrix. Here I test this hypothesis using a large dataset of macrolepidopteran DNA barcodes. Methodology/Principal Findings Taxon sampling was systematically increased in datamatrices containing macrolepidopteran DNA barcodes. Sixteen family groups were designated as concordance groups and two quantitative measures; the taxon consistency index and the taxon retention index, were used to assess any changes in phylogenetic signal as a result of the increase in taxon sampling. DNA barcodes alone, even with maximal taxon sampling (500 species per family), were not sufficient to reconstruct monophyly of families and increased taxon sampling generally increased the number of clades formed per family. However, the scores indicated a similar level of taxon retention (species from a family clustering together) in the cladograms as the number of species included in the datamatrix was increased, suggesting substantial phylogenetic signal below the ‘family’ branch. Conclusions/Significance The development of supermatrix, supertree or constrained tree approaches could enable the exploitation of the massive taxon sampling afforded through DNA barcodes for phylogenetics, connecting the twigs resolved by barcodes to the deep branches resolved through phylogenomics. PMID:21931848

  14. A Standardized Reference Data Set for Vertebrate Taxon Name Resolution

    PubMed Central

    Zermoglio, Paula F.; Guralnick, Robert P.; Wieczorek, John R.

    2016-01-01

    Taxonomic names associated with digitized biocollections labels have flooded into repositories such as GBIF, iDigBio and VertNet. The names on these labels are often misspelled, out of date, or present other problems, as they were often captured only once during accessioning of specimens, or have a history of label changes without clear provenance. Before records are reliably usable in research, it is critical that these issues be addressed. However, still missing is an assessment of the scope of the problem, the effort needed to solve it, and a way to improve effectiveness of tools developed to aid the process. We present a carefully human-vetted analysis of 1000 verbatim scientific names taken at random from those published via the data aggregator VertNet, providing the first rigorously reviewed, reference validation data set. In addition to characterizing formatting problems, human vetting focused on detecting misspelling, synonymy, and the incorrect use of Darwin Core. Our results reveal a sobering view of the challenge ahead, as less than 47% of name strings were found to be currently valid. More optimistically, nearly 97% of name combinations could be resolved to a currently valid name, suggesting that computer-aided approaches may provide feasible means to improve digitized content. Finally, we associated names back to biocollections records and fit logistic models to test potential drivers of issues. A set of candidate variables (geographic region, year collected, higher-level clade, and the institutional digitally accessible data volume) and their 2-way interactions all predict the probability of records having taxon name issues, based on model selection approaches. We strongly encourage further experiments to use this reference data set as a means to compare automated or computer-aided taxon name tools for their ability to resolve and improve the existing wealth of legacy data. PMID:26760296

  15. A Standardized Reference Data Set for Vertebrate Taxon Name Resolution.

    PubMed

    Zermoglio, Paula F; Guralnick, Robert P; Wieczorek, John R

    2016-01-01

    Taxonomic names associated with digitized biocollections labels have flooded into repositories such as GBIF, iDigBio and VertNet. The names on these labels are often misspelled, out of date, or present other problems, as they were often captured only once during accessioning of specimens, or have a history of label changes without clear provenance. Before records are reliably usable in research, it is critical that these issues be addressed. However, still missing is an assessment of the scope of the problem, the effort needed to solve it, and a way to improve effectiveness of tools developed to aid the process. We present a carefully human-vetted analysis of 1000 verbatim scientific names taken at random from those published via the data aggregator VertNet, providing the first rigorously reviewed, reference validation data set. In addition to characterizing formatting problems, human vetting focused on detecting misspelling, synonymy, and the incorrect use of Darwin Core. Our results reveal a sobering view of the challenge ahead, as less than 47% of name strings were found to be currently valid. More optimistically, nearly 97% of name combinations could be resolved to a currently valid name, suggesting that computer-aided approaches may provide feasible means to improve digitized content. Finally, we associated names back to biocollections records and fit logistic models to test potential drivers of issues. A set of candidate variables (geographic region, year collected, higher-level clade, and the institutional digitally accessible data volume) and their 2-way interactions all predict the probability of records having taxon name issues, based on model selection approaches. We strongly encourage further experiments to use this reference data set as a means to compare automated or computer-aided taxon name tools for their ability to resolve and improve the existing wealth of legacy data. PMID:26760296

  16. Myrmecomorba nylanderiae gen. et sp. nov., a microsporidian parasite of the tawny crazy ant Nylanderia fulva.

    PubMed

    Plowes, Robert M; Becnel, James J; LeBrun, Edward G; Oi, David H; Valles, Steven M; Jones, Nathan T; Gilbert, Lawrence E

    2015-07-01

    A new microsporidian genus and species, Myrmecomorba nylanderiae, is described from North American populations of the tawny crazy ant, Nylanderia fulva. This new species was found to be heterosporous producing several types of binucleate spores in both larval and adult stages and an abortive octosporoblastic sporogony in adult ants. While microsporidia are widespread arthropod parasites, this description represents only the fifth species described from an ant host. Molecular analysis indicated that this new taxon is phylogenetically closely allied to the microsporidian family Caudosporidae, a group known to parasitize aquatic black fly larvae. We report the presence of 3 spore types (Type 1 DK, Type 2 DK, and octospores) with infections found in all stages of host development and reproductive castes. This report documents the first pathogen infecting N. fulva, an invasive ant of considerable economic and ecological consequence. PMID:26031565

  17. Convergent coevolution in the domestication of coral mushrooms by fungus-growing ants.

    PubMed Central

    Munkacsi, A. B.; Pan, J. J.; Villesen, P.; Mueller, U. G.; Blackwell, M.; McLaughlin, D. J.

    2004-01-01

    Comparisons of phylogenetic patterns between coevolving symbionts can reveal rich details about the evolutionary history of symbioses. The ancient symbiosis between fungus-growing ants, their fungal cultivars, antibiotic-producing bacteria and cultivar-infecting parasites is dominated by a pattern of parallel coevolution, where the symbionts of each functional group are members of monophyletic groups. However, there is one outstanding exception in the fungus-growing ant system, the unidentified cultivar grown only by ants in the Apterostigma pilosum group. We classify this cultivar in the coral-mushroom family Pterulaceae using phylogenetic reconstructions based on broad taxon sampling, including the first mushroom collected from the garden of an ant species in the A. pilosum group. The domestication of the pterulaceous cultivar is independent from the domestication of the gilled mushrooms cultivated by all other fungus-growing ants. Yet it has the same overall assemblage of coevolved ant-cultivar-parasite-bacterium interactions as the other ant-grown fungal cultivars. This indicates a pattern of convergent coevolution in the fungus-growing ant system, where symbionts with both similar and very different evolutionary histories converge to functionally identical interactions. PMID:15315892

  18. 7 CFR 360.500 - Petitions to add a taxon to the noxious weed list.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Petitions to add a taxon to the noxious weed list. 360... PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.500 Petitions to add a taxon to the noxious weed list. A person may petition the Administrator to have a...

  19. 7 CFR 360.500 - Petitions to add a taxon to the noxious weed list.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Petitions to add a taxon to the noxious weed list. 360... PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.500 Petitions to add a taxon to the noxious weed list. A person may petition the Administrator to have a...

  20. 7 CFR 360.500 - Petitions to add a taxon to the noxious weed list.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Petitions to add a taxon to the noxious weed list. 360... PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.500 Petitions to add a taxon to the noxious weed list. A person may petition the Administrator to have a...

  1. 7 CFR 360.501 - Petitions to remove a taxon from the noxious weed lists.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Petitions to remove a taxon from the noxious weed...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition the Administrator to remove...

  2. 7 CFR 360.501 - Petitions to remove a taxon from the noxious weed lists.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Petitions to remove a taxon from the noxious weed...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition the Administrator to remove...

  3. 7 CFR 360.501 - Petitions to remove a taxon from the noxious weed lists.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Petitions to remove a taxon from the noxious weed...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition the Administrator to remove...

  4. 7 CFR 360.501 - Petitions to remove a taxon from the noxious weed lists.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Petitions to remove a taxon from the noxious weed...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition the Administrator to remove...

  5. 7 CFR 360.500 - Petitions to add a taxon to the noxious weed list.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Petitions to add a taxon to the noxious weed list. 360... PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.500 Petitions to add a taxon to the noxious weed list. A person may petition the Administrator to have a...

  6. Problematic use of energy drinks by adolescents.

    PubMed

    Kaminer, Yifrah

    2010-07-01

    Energy drinks (EDs) are caffeine-based beverages that commonly contain large doses of sugar, carbohydrates, and a variety of legal stimulants and supplements, such as guarana, taurine, ginseng, and vitamin B complex. These drinks are marketed for young people as natural alternatives that increase fun and improve physical and cognitive performance such as concentration, attention, and alertness. There are commonly held false perceptions that the consumption of EDs can reverse alcohol-related impairment, including motor coordination and visual reaction time, which are crucial for driving safety. This article reviews the literature on EDs and examines problematic use and potential negative consequences in young people. Special emphasis is devoted to safety concerns following combination of EDs with alcohol, which gives the user a false sense of control. PMID:20682226

  7. Two issues in archaeological phylogenetics: taxon construction and outgroup selection.

    PubMed

    O'Brien, Michael J; Lyman, R Lee; Saab, Youssef; Saab, Elias; Darwent, John; Glover, Daniel S

    2002-03-21

    Cladistics is widely used in biology and paleobiology to construct phylogenetic hypotheses, but rarely has it been applied outside those disciplines. There is, however, no reason to suppose that cladistics is not applicable to anything that evolves by cladogenesis and produces a nested hierarchy of taxa. This includes cultural phenomena such as languages and tools recovered from archaeological contexts. Two methodological issues assume primacy in attempts to extend cladistics to archaeological materials: the construction of analytical taxa and the selection of appropriate outgroups. In biology the species is the primary taxonomic unit used, irrespective of the debates that have arisen in phylogenetic theory over the nature of species. Also in biology the phylogenetic history of a group of taxa usually is well enough known that an appropriate taxon can be selected as an outgroup. No analytical unit parallel to the species exists in archaeology, and thus taxa have to be constructed specifically for phylogenetic analysis. One method of constructing taxa is paradigmatic classification, which defines classes (taxa) on the basis of co-occurring, unweighted character states. Once classes have been created, a form of occurrence seriation-an archaeological method based on the theory of cultural transmission and heritability-offers an objective basis for selecting an outgroup. PMID:12051970

  8. Field techniques for sampling ants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ants occur in most environments and ecologists ask a diverse array of questions involving ants. Thus, a key consideration in ant studies is to match the environment and question (and associated environmental variables) to the ant sampling technique. Since each technique has distinct limitations, usi...

  9. Confocal microscopy refines generic concept of a problematic taxon: rediagnosis of the genus Neoprothrix and remarks on female anatomy of eriophyoids (Acari: Eriophyoidea).

    PubMed

    Chetverikov, Philipp E; Desnitskiy, Alexey G; Navia, Denise

    2015-01-01

    Due to the higher resolution, confocal microscopy (CLSM) can be applied to refine the origin of tiny structures of the autofluorescent exoskeletons of microarthropods (mites in particular) which are hard to visualize using traditional differential interference contract light microscopy (DIC LM) and phase contrast light microscopy (PC LM). Three-dimensional (3D) reconstructions of the prodorsal shield topography of eriophyoid mites using Neoprothrix hibiscus Reis and Navia as a model, suggest that the structures originally treated as paired setae vi are two internal rod-like apodemes. Based on this, the genus Neoprothrix is excluded from the subfamily Prothricinae Amrine and transferred to the subfamily Sierraphytoptinae Keifer. Observations on partially cleared specimens of N. hibiscus showed that remnants of the central nervous system, paired glands and developing oocytes can be visualized using DIC LM and CLSM methods. New high quality microscope images are provided of recently described "flower-shaped" structures and two main components of yolk inclusions of the mature eggs inside the oviduct. PMID:25781123

  10. Fire Ant Bites

    MedlinePlus

    ... and the patient will develop difficulty breathing in addition to weakness. Patients who develop anaphylaxis and have a significant history of systemic reactions to fire ant stings should be checked for ...

  11. Ant traffic rules.

    PubMed

    Fourcassié, Vincent; Dussutour, Audrey; Deneubourg, Jean-Louis

    2010-07-15

    Many animals take part in flow-like collective movements. In most species, however, the flow is unidirectional. Ants are one of the rare group of organisms in which flow-like movements are predominantly bidirectional. This adds to the difficulty of the task of maintaining a smooth, efficient movement. Yet, ants seem to fare well at this task. Do they really? And if so, how do such simple organisms succeed in maintaining a smooth traffic flow, when even humans experience trouble with this task? How does traffic in ants compare with that in human pedestrians or vehicles? The experimental study of ant traffic is only a few years old but it has already provided interesting insights into traffic organization and regulation in animals, showing in particular that an ant colony as a whole can be considered as a typical self-organized adaptive system. In this review we will show that the study of ant traffic can not only uncover basic principles of behavioral ecology and evolution in social insects but also provide new insights into the study of traffic systems in general. PMID:20581264

  12. Ants and ant scent reduce bumblebee pollination of artificial flowers.

    PubMed

    Cembrowski, Adam R; Tan, Marcus G; Thomson, James D; Frederickson, Megan E

    2014-01-01

    Ants on flowers can disrupt pollination by consuming rewards or harassing pollinators, but it is difficult to disentangle the effects of these exploitative and interference forms of competition on pollinator behavior. Using highly rewarding and quickly replenishing artificial flowers that simulate male or female function, we allowed bumblebees (Bombus impatiens) to forage (1) on flowers with or without ants (Myrmica rubra) and (2) on flowers with or without ant scent cues. Bumblebees transferred significantly more pollen analogue both to and from ant-free flowers, demonstrating that interference competition with ants is sufficient to modify pollinator foraging behavior. Bees also removed significantly less pollen analogue from ant-scented flowers than from controls, making this the first study to show that bees can use ant scent to avoid harassment at flowers. Ant effects on pollinator behavior, possibly in addition to their effects on pollen viability, may contribute to the evolution of floral traits minimizing ant visitation. PMID:24334742

  13. Psychometric development of the Problematic Pornography Use Scale.

    PubMed

    Kor, Ariel; Zilcha-Mano, Sigal; Fogel, Yehuda A; Mikulincer, Mario; Reid, Rory C; Potenza, Marc N

    2014-05-01

    Despite the increased social acceptance and widespread use of pornography over the past few decades, reliable and valid instruments assessing problematic use of pornography are lacking. This paper reports the findings of three studies aimed at developing and validating a new scale measuring problematic pornography use. The Problematic Pornography Use Scale (PPUS) items showed high internal consistency, convergent validity, and construct validity. Exploratory and confirmatory factor analyses revealed four core factors relating to proposed domains of problematic pornography use. High PPUS scores were positively correlated with measures of psychopathology, low self-esteem and poor attachment. Although PPUS scores were related to other behavioral addictions, problematic pornography use as operationalized in the current paper appears to be uniquely distinguished from features of behavioral addictions relating to gambling and Internet use. Findings highlight the potential use of the PPUS for future research and possible clinical applications by defining problematic pornography use as a behavioral addiction. PMID:24583276

  14. Alate susceptibility in ants

    PubMed Central

    Ho, Eddie K H; Frederickson, Megan E

    2014-01-01

    Pathogens are predicted to pose a particular threat to eusocial insects because infections can spread rapidly in colonies with high densities of closely related individuals. In ants, there are two major castes: workers and reproductives. Sterile workers receive no direct benefit from investing in immunity, but can gain indirect fitness benefits if their immunity aids the survival of their fertile siblings. Virgin reproductives (alates), on the other hand, may be able to increase their investment in reproduction, rather than in immunity, because of the protection they receive from workers. Thus, we expect colonies to have highly immune workers, but relatively more susceptible alates. We examined the survival of workers, gynes, and males of nine ant species collected in Peru and Canada when exposed to the entomopathogenic fungus Beauveria bassiana. For the seven species in which treatment with B. bassiana increased ant mortality relative to controls, we found workers were significantly less susceptible compared with both alate sexes. Female and male alates did not differ significantly in their immunocompetence. Our results suggest that, as with other nonreproductive tasks in ant colonies like foraging and nest maintenance, workers have primary responsibility for colony immunity, allowing alates to specialize on reproduction. We highlight the importance of colony-level selection on individual immunity in ants and other eusocial organisms. PMID:25540683

  15. Alate susceptibility in ants.

    PubMed

    Ho, Eddie K H; Frederickson, Megan E

    2014-11-01

    Pathogens are predicted to pose a particular threat to eusocial insects because infections can spread rapidly in colonies with high densities of closely related individuals. In ants, there are two major castes: workers and reproductives. Sterile workers receive no direct benefit from investing in immunity, but can gain indirect fitness benefits if their immunity aids the survival of their fertile siblings. Virgin reproductives (alates), on the other hand, may be able to increase their investment in reproduction, rather than in immunity, because of the protection they receive from workers. Thus, we expect colonies to have highly immune workers, but relatively more susceptible alates. We examined the survival of workers, gynes, and males of nine ant species collected in Peru and Canada when exposed to the entomopathogenic fungus Beauveria bassiana. For the seven species in which treatment with B. bassiana increased ant mortality relative to controls, we found workers were significantly less susceptible compared with both alate sexes. Female and male alates did not differ significantly in their immunocompetence. Our results suggest that, as with other nonreproductive tasks in ant colonies like foraging and nest maintenance, workers have primary responsibility for colony immunity, allowing alates to specialize on reproduction. We highlight the importance of colony-level selection on individual immunity in ants and other eusocial organisms. PMID:25540683

  16. Utilization of Anting-Anting (Acalypha indica) Leaves as Antibacterial

    NASA Astrophysics Data System (ADS)

    Batubara, Irmanida; Wahyuni, Wulan Tri; Firdaus, Imam

    2016-01-01

    Anting-anting (Acalypha indica) plants is a species of plant having catkin type of inflorescence. This research aims to utilize anting-anting as antibacterial toward Streptococcus mutans and degradation of biofilm on teeth. Anting-anting leaves were extracted by maceration technique using methanol, chloroform, and n-hexane. Antibacterial and biofilm degradation assays were performed using microdilution technique with 96 well. n-Hexane extracts of anting-anting leaves gave the best antibacterial potency with minimum inhibitory concentration and minimum bactericidal concentration value of 500 μg/mL and exhibited good biofilm degradation activity. Fraction of F3 obtained from fractionation of n-hexane's extract with column chromatography was a potential for degradation of biofilm with IC50 value of 56.82 μg/mL. Alkaloid was suggested as antibacterial and degradation of biofilm in the active fraction.

  17. The impact of taxon sampling on phylogenetic inference: a review of two decades of controversy

    PubMed Central

    Nabhan, Ahmed Ragab

    2012-01-01

    Over the past two decades, there has been a long-standing debate about the impact of taxon sampling on phylogenetic inference. Studies have been based on both real and simulated data sets, within actual and theoretical contexts, and using different inference methods, to study the impact of taxon sampling. In some cases, conflicting conclusions have been drawn for the same data set. The main questions explored in studies to date have been about the effects of using sparse data, adding new taxa, including more characters from genome sequences and using different (or concatenated) locus regions. These questions can be reduced to more fundamental ones about the assessment of data quality and the design guidelines of taxon sampling in phylogenetic inference experiments. This review summarizes progress to date in understanding the impact of taxon sampling on the accuracy of phylogenetic analysis. PMID:21436145

  18. An Examination of Predictor Variables for Problematic Internet Use

    ERIC Educational Resources Information Center

    Bulut Serin, Nerguz

    2011-01-01

    This study examines problematic Internet use among university students in terms of gender, while also gauging the impact of personality traits, life satisfaction and loneliness variables on problematic Internet use. A total of 411 university students studying Education in North Cyprus participated in the study. The participants were selected using…

  19. Organizational Theory, Organizational Communication, Organizational Knowledge, and Problematic Integration.

    ERIC Educational Resources Information Center

    McPhee, Robert D.; Zaug, Pamela

    2001-01-01

    Argues that three traditions of theory about organizational communication have special relevance to the ideas of problematic integration theory. Indicates the implications of theoretic currents and notes that the main implication is that problematic integration looks very different in the context of a complex communication system. (SG)

  20. Ant-based computing.

    PubMed

    Michael, Loizos

    2009-01-01

    A biologically and physically plausible model for ants and pheromones is proposed. It is argued that the mechanisms described in this model are sufficiently powerful to reproduce the necessary components of universal computation. The claim is supported by illustrating the feasibility of designing arbitrary logic circuits, showing that the interactions of ants and pheromones lead to the expected behavior, and presenting computer simulation results to verify the circuits' working. The conclusions of this study can be taken as evidence that coherent deterministic and centralized computation can emerge from the collective behavior of simple distributed Markovian processes such as those followed by biological ants, but also, more generally, by artificial agents with limited computational and communication abilities. PMID:19239348

  1. The Ants Go Marching Millions by Millions: Invasive Ant Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive ants are a worldwide problem that is expanding both geographically and in intensity. Population explosions of invasive ants can overrun landscapes and inundate structures. Pest management professionals are often the first responders to complaints about invading ants. This session will fo...

  2. The ants go marching millions by millions: invasive ant research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive ants are a worldwide problem that is expanding both geographically and in intensity. Population explosions of invasive ants can overrun landscapes and inundate structures. Pest management professionals are often the first responders to complaints about invading ants. This session will fo...

  3. Routing Vehicles with Ants

    NASA Astrophysics Data System (ADS)

    Tan, Wen Fang; Lee, Lai Soon; Majid, Zanariah Abdul; Seow, Hsin Vonn

    Routing vehicles involve the design of an optimal set of routes for a fleet of vehicles to serve a number of customers with known demands. This research develops an Ant Colony Optimization for the vehicle routing with one central depot and identical vehicles. The procedure simulates the behavior of real ants that always find the shortest path between their nest and a food source through a form of communication, pheromone trail. Finally, preliminary results on the learning of the algorithm testing on benchmark data set will be presented in this paper.

  4. Universality in ant behaviour.

    PubMed

    Christensen, Kim; Papavassiliou, Dario; de Figueiredo, Alexandre; Franks, Nigel R; Sendova-Franks, Ana B

    2015-01-01

    Prediction for social systems is a major challenge. Universality at the social level has inspired a unified theory for urban living but individual variation makes predicting relationships within societies difficult. Here, we show that in ant societies individual average speed is higher when event duration is longer. Expressed as a single scaling function, this relationship is universal because for any event duration an ant, on average, moves at the corresponding average speed except for a short acceleration and deceleration at the beginning and end. This establishes cause and effect within a social system and may inform engineering and control of artificial ones. PMID:25411406

  5. Ants: the supreme soil manipulators

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review focuses on the semiochemical interactions between ants and their soil environment. Ants occupy virtually every ecological niche and have evolved mechanisms to not just cope with, but also manipulate soil organisms. The metapleural gland, specific to ants was thought to be the major sourc...

  6. Unraveling Trichoderma species in the attine ant environment: description of three new taxa.

    PubMed

    Montoya, Quimi Vidaurre; Meirelles, Lucas Andrade; Chaverri, Priscila; Rodrigues, Andre

    2016-05-01

    Fungus-growing "attine" ants forage diverse substrates to grow fungi for food. In addition to the mutualistic fungal partner, the colonies of these insects harbor a rich microbiome composed of bacteria, filamentous fungi and yeasts. Previous work reported some Trichoderma species in the fungus gardens of leafcutter ants. However, no studies systematically addressed the putative association of Trichoderma with attine ants, especially in non-leafcutter ants. Here, a total of 62 strains of Trichoderma were analyzed using three molecular markers (ITS, tef1 and rpb2). In addition, 30 out of 62 strains were also morphologically examined. The strains studied correspond to the largest sampling carried out so far for Trichoderma in the attine ant environment. Our results revealed the richness of Trichoderma in this environment, since we found 20 Trichoderma species, including three new taxa described in the present work (Trichoderma attinorum, Trichoderma texanum and Trichoderma longifialidicum spp. nov.) as well as a new phylogenetic taxon (LESF 545). Moreover, we show that all 62 strains grouped within different clades across the Trichoderma phylogeny, which are identical or closely related to strains derived from several other environments. This evidence supports the transient nature of the genus Trichoderma in the attine ant colonies. The discovery of three new species suggests that the dynamic foraging behavior of these insects might be responsible for accumulation of transient fungi into their colonies, which might hold additional fungal taxa still unknown to science. PMID:26885975

  7. Ant allergens and hypersensitivity reactions in response to ant stings.

    PubMed

    Potiwat, Rutcharin; Sitcharungsi, Raweerat

    2015-12-01

    Hypersensitivity reactions caused by ant stings are increasingly recognized as an important cause of death by anaphylaxis. Only some species of ants ( e.g. Solenopsis spp., Myrmecia spp., and Pachycondyla spp.) cause allergic reactions. Ant species are identified by evaluating the morphologic structures of worker ants or by molecular techniques. Ant venom contains substances, including acids and alkaloids, that cause toxic reactions, and those from Solenopsis invicta or the imported fire ant have been widely studied. Piperidine alkaloids and low protein contents can cause local reactions (sterile pustules) and systemic reactions (anaphylaxis). Imported fire ant venoms are cross-reactive; for example, the Sol i 1 allergen from S. invicta has cross-reactivity with yellow jacket phospholipase. The Sol i 3 allergen is a member of the antigen 5 family that has amino acid sequence identity with vespid antigen 5. The clinical presentations of ant hypersensitivity are categorized into immediate and delayed reactions: immediate reactions, such as small local reactions, large local reactions, and systemic reactions, occur within 1-4 hours after the ant stings, whereas delayed reactions, such as serum sickness and vasculitis, usually occur more than 4 hours after the stings. Tools for the diagnosis of ant hypersensitivity are skin testing, serum specific IgE, and sting challenge tests. Management of ant hypersensitivity can be divided into immediate (epinephrine, corticosteroids), symptomatic (antihistamines, bronchodilators), supportive (fluid resuscitation, oxygen therapy), and preventive (re-sting avoidance and immunotherapy) treatments. PMID:26708389

  8. Tiny, Powerful, Awesome Ants!

    ERIC Educational Resources Information Center

    Tate, Kathleen

    2007-01-01

    Peering through a thematic science lens--elementary students embarked on a one-week study of ants during a month-long summer school program. This integrated unit addressed reading and writing skills while developing the science-process skills of observation, inferring, and communicating in a motivating and authentic way. Pre- and post-assessments…

  9. Fire Ant Allergy

    MedlinePlus

    ... In extreme cases, a rapid fall in blood pressure may result in shock and loss of consciousness. Symptoms of anaphylaxis require emergency medical treatment. Given the severity of a potential reaction, an accurate diagnosis for fire ant allergy is key to being prepared for ...

  10. Patient-reported problematic symptoms in an ALS treatment trial.

    PubMed

    Raheja, Divisha; Stephens, Helen E; Lehman, Erik; Walsh, Susan; Yang, Chengwu; Simmons, Zachary

    2016-01-01

    This study was undertaken to determine which symptoms are perceived to be most problematic for patients with ALS and how their severity changes over time. A retrospective study was performed of data from a randomized, double-blind, placebo-controlled trial of ceftriaxone in ALS. Participants completed the ALS Specific Quality of Life Instrument (ALSSQoL) at baseline and at intervals up to 96 weeks. Ten ALSSQoL items ask participants to rate how problematic symptoms are (the subjective feeling of burden of these symptoms), ranging from 0 (no problem) to 10 (tremendous problem). Six are non-bulbar (pain, fatigue, breathing, strength and ability to move, sleep, and bowel and bladder) and four are bulbar (eating, speaking, excessive saliva, and mucus). Results revealed that there were 82 subjects (56% males, mean age 53 ± 10.3 years) with ALSSQoL data for weeks 0 and 96. All 10 symptoms became more problematic over time. For non-bulbar symptoms, strength/ability to move and fatigue were the most problematic. Speaking was the most problematic bulbar symptom. In conclusion, although all the symptoms in the ALSSQoL were acknowledged as problematic, some had greater impact than others. All became more problematic over time. This should help prioritize research into symptom management, and assist individual clinicians in their approach to patient care. PMID:26824413

  11. Is problematic mobile phone use explained by chronotype and personality?

    PubMed

    Demirhan, Eda; Randler, Christoph; Horzum, Mehmet Barış

    2016-01-01

    In this study, the relationships among problematic mobile phone use, age, gender, personality and chronotype of Turkish university students were examined. The study included 902 university students (73% female, 27% male) and their participation in the study was anonymous and voluntary. Data were collected from each participant by assessing a demographic questionnaire, Composite Scale of Morningness (CSM) as a measure of chronotype, the Big Five Inventory (BIG-5) for personality assessment and Mobile Phone Problem Usage Scale (MPPUS). The most important result was that CSM scores were the best predictor for problematic mobile phone usage, and as a consequence, evening-oriented university students scored higher on the MPPUS. This result remained, even when compared with the most influential personality predictor, conscientiousness. In addition, while extraversion positively predicted, emotional stable and chronotype negatively predicted problematic mobile phone use. Lastly, age and gender were not predictors of problematic mobile phone use. PMID:27128819

  12. The Frugal Cosmic Ant

    NASA Astrophysics Data System (ADS)

    2007-09-01

    Using ESO's Very Large Telescope Interferometer and its unique ability to see small details, astronomers have uncovered a flat, nearly edge-on disc of silicates in the heart of the magnificent Ant Nebula. The disc seems, however, too 'skinny' to explain how the nebula got its intriguing ant-like shape. ESO PR Photo 42/07 ESO PR Photo 42/07 A Disc in the Ant Nebula The Ant Nebula is one of the most striking planetary nebulae known. Planetary nebulae - whose name arises because most are spherical and looked like planets when they were first discovered through older, less powerful telescopes - are glowing structures of gas cast off by solar-like stars at the ends of their lives. The morphology of the Ant Nebula - a bright core, three nested pairs of bipolar lobes and a ring-like outflow - is so unique that it was nicknamed the 'Chamber of Horrors' of planetary nebulae in the late 1950s. But how can a spherical star produce such complex structures? The answer, many astronomers think, requires understanding of the discs surrounding the central star. By their nature, these discs bear witness to the phenomena that lead to the asymmetrical structures of planetary nebulae. "The challenge is to actually detect these discs," explains team leader Olivier Chesneau, from the Observatoire de la Côte d'Azur, France. "Most astronomical instruments do not have a sharp enough view to find, let alone study them. The Very Large Telescope Interferometer however, with its exceptionally high spatial resolution, is a powerful disc-hunter." The disc of the Ant Nebula, which cannot be detected with a single 8.2-m VLT Unit Telescope, was uncovered in the interferometric mode where two 8.2-m Unit Telescopes were used to combine light, through the MID-infrared Interferometric instrument (MIDI). The observations reveal a flat, nearly edge-on disc whose major axis is perpendicular to the axis of the bipolar lobes. The disc extends from about 9 times the mean distance between the Earth and the

  13. Distributed nestmate recognition in ants

    PubMed Central

    Esponda, Fernando; Gordon, Deborah M.

    2015-01-01

    We propose a distributed model of nestmate recognition, analogous to the one used by the vertebrate immune system, in which colony response results from the diverse reactions of many ants. The model describes how individual behaviour produces colony response to non-nestmates. No single ant knows the odour identity of the colony. Instead, colony identity is defined collectively by all the ants in the colony. Each ant responds to the odour of other ants by reference to its own unique decision boundary, which is a result of its experience of encounters with other ants. Each ant thus recognizes a particular set of chemical profiles as being those of non-nestmates. This model predicts, as experimental results have shown, that the outcome of behavioural assays is likely to be variable, that it depends on the number of ants tested, that response to non-nestmates changes over time and that it changes in response to the experience of individual ants. A distributed system allows a colony to identify non-nestmates without requiring that all individuals have the same complete information and helps to facilitate the tracking of changes in cuticular hydrocarbon profiles, because only a subset of ants must respond to provide an adequate response. PMID:25833853

  14. Distributed nestmate recognition in ants.

    PubMed

    Esponda, Fernando; Gordon, Deborah M

    2015-05-01

    We propose a distributed model of nestmate recognition, analogous to the one used by the vertebrate immune system, in which colony response results from the diverse reactions of many ants. The model describes how individual behaviour produces colony response to non-nestmates. No single ant knows the odour identity of the colony. Instead, colony identity is defined collectively by all the ants in the colony. Each ant responds to the odour of other ants by reference to its own unique decision boundary, which is a result of its experience of encounters with other ants. Each ant thus recognizes a particular set of chemical profiles as being those of non-nestmates. This model predicts, as experimental results have shown, that the outcome of behavioural assays is likely to be variable, that it depends on the number of ants tested, that response to non-nestmates changes over time and that it changes in response to the experience of individual ants. A distributed system allows a colony to identify non-nestmates without requiring that all individuals have the same complete information and helps to facilitate the tracking of changes in cuticular hydrocarbon profiles, because only a subset of ants must respond to provide an adequate response. PMID:25833853

  15. Mechanics of fire ant aggregations

    NASA Astrophysics Data System (ADS)

    Tennenbaum, Michael; Liu, Zhongyang; Hu, David; Fernandez-Nieves, Alberto

    2016-01-01

    Fire ants link their bodies to form aggregations; these can adopt a variety of structures, they can drip and spread, or withstand applied loads. Here, by using oscillatory rheology, we show that fire ant aggregations are viscoelastic. We find that, at the lowest ant densities probed and in the linear regime, the elastic and viscous moduli are essentially identical over the spanned frequency range, which highlights the absence of a dominant mode of structural relaxation. As ant density increases, the elastic modulus rises, which we interpret by alluding to ant crowding and subsequent jamming. When deformed beyond the linear regime, the aggregation flows, exhibiting shear-thinning behaviour with a stress load that is comparable to the maximum load the aggregation can withstand before individual ants are torn apart. Our findings illustrate the rich, collective mechanical behaviour that can arise in aggregations of active, interacting building blocks.

  16. Mechanics of fire ant aggregations.

    PubMed

    Tennenbaum, Michael; Liu, Zhongyang; Hu, David; Fernandez-Nieves, Alberto

    2016-01-01

    Fire ants link their bodies to form aggregations; these can adopt a variety of structures, they can drip and spread, or withstand applied loads. Here, by using oscillatory rheology, we show that fire ant aggregations are viscoelastic. We find that, at the lowest ant densities probed and in the linear regime, the elastic and viscous moduli are essentially identical over the spanned frequency range, which highlights the absence of a dominant mode of structural relaxation. As ant density increases, the elastic modulus rises, which we interpret by alluding to ant crowding and subsequent jamming. When deformed beyond the linear regime, the aggregation flows, exhibiting shear-thinning behaviour with a stress load that is comparable to the maximum load the aggregation can withstand before individual ants are torn apart. Our findings illustrate the rich, collective mechanical behaviour that can arise in aggregations of active, interacting building blocks. PMID:26501413

  17. Parasitoid secretions provoke ant warfare.

    PubMed

    Thomas, J A; Knapp, J J; Akino, T; Gerty, S; Wakamura, S; Simcox, D J; Wardlaw, J C; Elmes, G W

    2002-05-30

    Insect social parasites are extreme specialists that typically use mimicry or stealth to enter ant colonies to exploit the rich, but fiercely protected, resources within their nests. Here we show how a parasitic wasp (parasitoid) contrives to reach its host, itself an endangered species of social parasite that lives inside the brood chambers of ant nests, by releasing semiochemicals to induce in-fighting between worker ants, locking the colony in combat and leaving it underprotected. Four of these chemicals are new to biology and have the potential to control pest species by inducing different agonistic behaviours in ants. PMID:12037556

  18. Problematic internet use: proposed classification and diagnostic criteria.

    PubMed

    Shapira, Nathan A; Lessig, Mary C; Goldsmith, Toby D; Szabo, Steven T; Lazoritz, Martin; Gold, Mark S; Stein, Dan J

    2003-01-01

    Since the mid-1990s, there have been frequent reports of individuals whose use of the computer and internet is problematic. Given the recent expansion and the expected increase in internet availability and usage in the coming years, it is important that healthcare professionals be informed about this behavior and its associated problems. Recently, psychological and psychiatric literature has described individuals that exhibit problematic internet use who often suffer from other psychiatric disorders. In the face of this comorbidity, it is essential to evaluate whether these individuals represent a distinct class of disorder, or a manifestation/coping mechanism related to other underlying diagnosis. In either event, problematic internet use negatively impacts social and emotional functioning. Based on the current limited empirical evidence, problematic internet use may best be classified as an impulse control disorder. It is therefore imperative that problematic internet use be appropriately identified among symptomatic individuals. For these reasons, we propose specific diagnostic criteria that will allow for consistent identification and assist in further study of this behavior. PMID:12820176

  19. Fire ant microsporidia acquired by parasitoid flies of fire ants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The microsporidium Kneallhazia (formerly Thelohania) solenopsae and parasitoid flies in the genus Pseudacteon are natural enemies of the invasive fire ant, Solenopsis invicta. Pseudacteon flies oviposit into adult fire ants, where maggots that eclose from eggs migrate to the ants’ head, pupate, and...

  20. Dimensionality vs taxonicity of schizotypy: some new data and challenges ahead.

    PubMed

    Everett, Kirsty V; Linscott, Richard J

    2015-03-01

    Heterogeneity in the expression of schizotypy may arise from underlying dimensional processes or a taxonic population structure. In a 2-phase study, we tested the taxonicity of self-reported schizotypy within a general psychiatric sample (n = 109) and examined taxon validity by testing its association with clinical schizotaxia in follow-up subsamples. Taxometric analyses indicated a taxonic structure (schizotypy prevalence = 38.8%) provided the best description of the underlying population distribution. After a year, schizotypal (n = 14) and nonschizotypal (n = 14) subsamples returned for diagnosis of clinical schizotaxia by assessment of executive functioning, attention, memory, and negative symptoms. Seven patients met diagnostic criteria, all members of the schizotypy class. Schizotypy was associated with impaired attention and memory, more negative symptoms, poorer global functioning, and more extensive psychiatric histories. We reconcile inconsistencies in the literature by discussing threats to the validity of this and similar research on Meehl's taxonomic model of schizotypy, including conceptual limitations of the lexical hypothesis and conventions of factor analysis. Scrutiny of Meehl's model should involve disambiguation and better measurement of the schizotaxia-schizotypy phenotype. PMID:25810059

  1. Dimensionality vs Taxonicity of Schizotypy: Some New Data and Challenges Ahead

    PubMed Central

    Everett, Kirsty V.; Linscott, Richard J.

    2015-01-01

    Heterogeneity in the expression of schizotypy may arise from underlying dimensional processes or a taxonic population structure. In a 2-phase study, we tested the taxonicity of self-reported schizotypy within a general psychiatric sample (n = 109) and examined taxon validity by testing its association with clinical schizotaxia in follow-up subsamples. Taxometric analyses indicated a taxonic structure (schizotypy prevalence = 38.8%) provided the best description of the underlying population distribution. After a year, schizotypal (n = 14) and nonschizotypal (n = 14) subsamples returned for diagnosis of clinical schizotaxia by assessment of executive functioning, attention, memory, and negative symptoms. Seven patients met diagnostic criteria, all members of the schizotypy class. Schizotypy was associated with impaired attention and memory, more negative symptoms, poorer global functioning, and more extensive psychiatric histories. We reconcile inconsistencies in the literature by discussing threats to the validity of this and similar research on Meehl’s taxonomic model of schizotypy, including conceptual limitations of the lexical hypothesis and conventions of factor analysis. Scrutiny of Meehl’s model should involve disambiguation and better measurement of the schizotaxia-schizotypy phenotype. PMID:25810059

  2. Psychopathy as a Taxon: Evidence That Psychopaths Are a Discrete Class.

    ERIC Educational Resources Information Center

    Harris, Grant T.; And Others

    1994-01-01

    Applied taxometric analyses to construct of psychopathy (as measured by Psychopathy Checklist) and to several variables reflecting antisocial childhood, adult criminality, and criminal recidivism. Findings from 653 serious offenders assessed or treated in maximum-security institution supported existence of taxon underlying psychopathy. Childhood…

  3. [Problematic online gaming. A review of the literature].

    PubMed

    Nagygyörgy, Katalin; Pápay, Orsolya; Urbán, Róbert; Farkas, Judit; Kun, Bernadette; Griffiths, Mark; Demetrovics, Zsolt

    2013-01-01

    In parallel with the increasing popularity of online games, researchers have reported an increasing number of problematic users. For this reason there is a growing amount of literature analyzing the effects of online games. The present review described the evolution of online games as well as their types and specific characteristics of these types. This review examines (i) the question of definition, (ii) symptoms of problematic use, (iii) the measurement instruments (iv) prevalence data, (v) issues of etiology, (vi) the results of comorbidity, and (vii) the main trends and results in the area of prevention and treatment. PMID:23880511

  4. Autonomy in ants and humans.

    PubMed

    Carpendale, Jeremy I M; Frayn, Michael

    2016-01-01

    Drawing lessons regarding the consequences of ultrasociality in ants and humans depends crucially on recognizing differences as well as similarities in the way that species are social. We focus on Gowdy & Krall's use of the concept of autonomy to explicate essential differences in the ways in which ants and humans are social. PMID:27562193

  5. Ant navigation: reading geometrical signposts.

    PubMed

    Collett, Thomas S; Waxman, David

    2005-03-01

    Ants often travel along complex pheromone trail systems between their nest and foraging areas. A new and surprising discovery is that Pharaoh's ants can work out from the geometry of individual branch points on the trail whether they are heading towards or away from the nest. PMID:15753029

  6. Dominance Hierarchies in Leptothorax Ants

    NASA Astrophysics Data System (ADS)

    Cole, Blaine J.

    1981-04-01

    The social organization of Leptothorax allardycei is unique among ant species thus far studied. The workers form linear dominance hierarchies characterized by routine displays of dominance, avoidance behavior, and even fighting. The high-ranking ants are favored in liquid food exchange, have greater ovarian development, and produce 20 percent of the eggs.

  7. Temperature: Human Regulating, Ants Conforming

    ERIC Educational Resources Information Center

    Clopton, Joe R.

    2007-01-01

    Biological processes speed up as temperature rises. Procedures for demonstrating this with ants traveling on trails, and data gathered by students on the Argentine ant ("Linepithema humile") are presented. The concepts of temperature regulation and conformity are detailed with a focus on the processes rather than on terms that label the organisms.

  8. Evolution of Fire Ant Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The imported fire ants that entered the United States over 70 years ago have spread within the country to over 129.5 million ha. Efforts to stop the expansion and suppress fire ant populations have resulted in changing methods of control. Initial efforts focused on treating individual nests with h...

  9. AntR-mediated bidirectional activation of antA and antR, anthranilate degradative genes in Pseudomonas aeruginosa.

    PubMed

    Kim, Soo-Kyoung; Im, Su-Jin; Yeom, Doo-Hwan; Lee, Joon-Hee

    2012-08-15

    Bidirectional activation of transcription is a peculiar regulation mode of gene expression. In this study, we show that genes involved in the metabolism of anthranilate, a precursor of biosynthesis of tryptophan and Pseudomonas quinolone signal (PQS) are regulated by this bidirectional activation of transcription. Anthranilate is degraded by anthranilate dioxygenase complex encoded by antABC operon, and AntR, a LysR-type regulator encoded by antR activates the transcription of antABC operon in the presence of anthranilate. In P. aeruginosa, antABC and antR are divergently located and AntR binds to the intergenic region between antA and antR to activate the antABC transcription. In this study, we determined the transcriptional start site of the antA promoter (antA(p)) and AntR-responsive elements (AREs) in P. aeruginosa. The upstream deletion analysis of antA(p) and in vitro gel shift assay with purified AntR showed that there are two AREs at -194 to -148 and -88 to -47 regions. We also found that AntR activates antR promoter (antR(p)) in the opposite direction and both AREs are important in the bidirectional activation of antA(p) and antR(p). Two AREs have different binding affinities to AntR and the strength of transcriptional activation was dramatically asymmetric depending on the direction. We suggest that the different affinities of two AREs may explain the asymmetry of the bidirectional activation by AntR. PMID:22609066

  10. Cultural differences in ant-dipping tool length between neighbouring chimpanzee communities at Kalinzu, Uganda.

    PubMed

    Koops, Kathelijne; Schöning, Caspar; Isaji, Mina; Hashimoto, Chie

    2015-01-01

    Cultural variation has been identified in a growing number of animal species ranging from primates to cetaceans. The principal method used to establish the presence of culture in wild populations is the method of exclusion. This method is problematic, since it cannot rule out the influence of genetics and ecology in geographically distant populations. A new approach to the study of culture compares neighbouring groups belonging to the same population. We applied this new approach by comparing ant-dipping tool length between two neighbouring communities of chimpanzees (Pan troglodytes schweinfurthii) in the Kalinzu Forest, Uganda. Ant-dipping tool length varies across chimpanzee study sites in relation to army ant species (Dorylus spp.) and dipping location (nest vs. trail). We compared the availability of army ant species and dipping tool length between the two communities. M-group tools were significantly longer than S-group tools, despite identical army ant target species availabilities. Moreover, tool length in S-group was shorter than at all other sites where chimpanzees prey on epigaeic ants at nests. Considering the lack of ecological differences between the two communities, the tool length difference appears to be cultural. Our findings highlight how cultural knowledge can generate small-scale cultural diversification in neighbouring chimpanzee communities. PMID:26198006

  11. Cultural differences in ant-dipping tool length between neighbouring chimpanzee communities at Kalinzu, Uganda

    PubMed Central

    Koops, Kathelijne; Schöning, Caspar; Isaji, Mina; Hashimoto, Chie

    2015-01-01

    Cultural variation has been identified in a growing number of animal species ranging from primates to cetaceans. The principal method used to establish the presence of culture in wild populations is the method of exclusion. This method is problematic, since it cannot rule out the influence of genetics and ecology in geographically distant populations. A new approach to the study of culture compares neighbouring groups belonging to the same population. We applied this new approach by comparing ant-dipping tool length between two neighbouring communities of chimpanzees (Pan troglodytes schweinfurthii) in the Kalinzu Forest, Uganda. Ant-dipping tool length varies across chimpanzee study sites in relation to army ant species (Dorylus spp.) and dipping location (nest vs. trail). We compared the availability of army ant species and dipping tool length between the two communities. M-group tools were significantly longer than S-group tools, despite identical army ant target species availabilities. Moreover, tool length in S-group was shorter than at all other sites where chimpanzees prey on epigaeic ants at nests. Considering the lack of ecological differences between the two communities, the tool length difference appears to be cultural. Our findings highlight how cultural knowledge can generate small-scale cultural diversification in neighbouring chimpanzee communities. PMID:26198006

  12. Discovery–dominance trade-off among widespread invasive ant species

    PubMed Central

    Bertelsmeier, Cleo; Avril, Amaury; Blight, Olivier; Jourdan, Hervé; Courchamp, Franck

    2015-01-01

    Ants are among the most problematic invasive species. They displace numerous native species, alter ecosystem processes, and can have negative impacts on agriculture and human health. In part, their success might stem from a departure from the discovery–dominance trade-off that can promote co-existence in native ant communities, that is, invasive ants are thought to be at the same time behaviorally dominant and faster discoverers of resources, compared to native species. However, it has not yet been tested whether similar asymmetries in behavioral dominance, exploration, and recruitment abilities also exist among invasive species. Here, we establish a dominance hierarchy among four of the most problematic invasive ants (Linepithema humile, Lasius neglectus, Wasmannia auropunctata, Pheidole megacephala) that may be able to arrive and establish in the same areas in the future. To assess behavioral dominance, we used confrontation experiments, testing the aggressiveness in individual and group interactions between all species pairs. In addition, to compare discovery efficiency, we tested the species’ capacity to locate a food resource in a maze, and the capacity to recruit nestmates to exploit a food resource. The four species differed greatly in their capacity to discover resources and to recruit nestmates and to dominate the other species. Our results are consistent with a discovery–dominance trade-off. The species that showed the highest level of interspecific aggressiveness and dominance during dyadic interactions. PMID:26257879

  13. Discovery-dominance trade-off among widespread invasive ant species.

    PubMed

    Bertelsmeier, Cleo; Avril, Amaury; Blight, Olivier; Jourdan, Hervé; Courchamp, Franck

    2015-07-01

    Ants are among the most problematic invasive species. They displace numerous native species, alter ecosystem processes, and can have negative impacts on agriculture and human health. In part, their success might stem from a departure from the discovery-dominance trade-off that can promote co-existence in native ant communities, that is, invasive ants are thought to be at the same time behaviorally dominant and faster discoverers of resources, compared to native species. However, it has not yet been tested whether similar asymmetries in behavioral dominance, exploration, and recruitment abilities also exist among invasive species. Here, we establish a dominance hierarchy among four of the most problematic invasive ants (Linepithema humile, Lasius neglectus, Wasmannia auropunctata, Pheidole megacephala) that may be able to arrive and establish in the same areas in the future. To assess behavioral dominance, we used confrontation experiments, testing the aggressiveness in individual and group interactions between all species pairs. In addition, to compare discovery efficiency, we tested the species' capacity to locate a food resource in a maze, and the capacity to recruit nestmates to exploit a food resource. The four species differed greatly in their capacity to discover resources and to recruit nestmates and to dominate the other species. Our results are consistent with a discovery-dominance trade-off. The species that showed the highest level of interspecific aggressiveness and dominance during dyadic interactions. PMID:26257879

  14. Problematic drinking, impulsivity, and physical IPV perpetration: A dyadic analysis.

    PubMed

    Leone, Ruschelle M; Crane, Cory A; Parrott, Dominic J; Eckhardt, Christopher I

    2016-05-01

    Alcohol use and impulsivity are 2 known risk factors for intimate partner violence (IPV). The current study examined the independent and interactive effects of problematic drinking and 5 facets of impulsivity (i.e., negative urgency, positive urgency, sensation seeking, lack of premeditation, and lack of perseverance) on perpetration of physical IPV within a dyadic framework. Participants were 289 heavy drinking heterosexual couples (total N = 578) with a recent history of psychological and/or physical IPV recruited from 2 metropolitan U.S. cities. Parallel multilevel actor partner interdependence models were used and demonstrated actor problematic drinking, negative urgency, and lack of perseverance were associated with physical IPV. Findings also revealed associations between partner problematic drinking and physical IPV as well as significant Partner Problematic Drinking × Actor Impulsivity (Negative Urgency and Positive Urgency) interaction effects on physical IPV. Findings highlight the importance of examining IPV within a dyadic framework and are interpreted using the I3 metatheoretical model. (PsycINFO Database Record PMID:26828640

  15. The prevalence of problematic video gamers in the Netherlands.

    PubMed

    Haagsma, Maria C; Pieterse, Marcel E; Peters, Oscar

    2012-03-01

    This study surveyed Dutch adolescents and adults about their video gaming behavior to assess the prevalence of problematic gaming. A representative national panel of 902 respondents aged 14 to 81 took part in the study. The results show that gaming in general is a wide-spread and popular activity among the Dutch population. Browser games (small games played via the internet) and offline casual games (e.g., offline card games) were reported as most popular type of game. Online games (e.g., massively multiplayer online role-playing games) are played by a relatively small part of the respondents, yet considerably more time is spent on these online games than on browser games, offline casual games, and offline games (e.g., offline racing games). The prevalence of problematic gaming in the total sample is 1.3 percent. Among adolescents and young adults problematic gaming occurs in 3.3 percent of cases. Particularly male adolescents seem to be more vulnerable to developing problematic gaming habits. PMID:22313358

  16. Loyalty: Why Is It so Problematic in Athletics?

    ERIC Educational Resources Information Center

    Stoll, Sharon Kay

    2012-01-01

    What is loyalty and why is it problematic in athletics? The author discusses the ethical lapses that can occur when a powerful social value, "loyalty," trumps individuals' ability to make moral decisions. She argues that education about morality should be a necessary part of sport education and explains how moral education programs can make a…

  17. Prevalence of Problematic Video Gaming among Ontario Adolescents

    ERIC Educational Resources Information Center

    Turner, Nigel E.; Paglia-Boak, Angela; Ballon, Bruce; Cheung, Joyce T. W.; Adlaf, Edward M.; Henderson, Joanna; Chan, Vincy; Rehm, Jurgen; Hamilton, Hayley; Mann, Robert E.

    2012-01-01

    Video game playing has become a very popular activity among adolescents. Its impact on the mental health and well-being of players is just beginning to be explored. This paper reports on the prevalence of problematic gaming in a representative sample of 2,832 Ontario students in grades 7 to 12. The survey included questions about the school grade,…

  18. Association between internet gambling and problematic internet use among adolescents.

    PubMed

    Tsitsika, Artemis; Critselis, Elena; Janikian, Mari; Kormas, George; Kafetzis, Dimitrios A

    2011-09-01

    The study objectives were to evaluate the correlates and psychosocial implications of internet gambling among adolescents, as well as the association between internet gambling and problematic internet use. A cross-sectional study design was applied among a random sample (N = 484) of adolescents (71.2% boys; 28.8% girls; mean age ± standard deviation, SD = 14.88 ± 0.55 years). Self-completed questionnaires, including internet gambling practices, internet use characteristics, Young Internet Addiction Test, and Strengths and Difficulties Questionnaire were utilized. The prevalence of internet gambling was 15.1%. Internet gambling was associated with psychosocial maladjustment, including Abnormal Conduct Problems (gender adjusted odds ratio, AOR = 3.83; 95% confidence interval, 95% CI: 1.86-7.92) and Borderline Peer Problems (AOR = 2.04; 95% CI: 1.09-3.85). The likelihood of concomitant problematic internet use was significantly higher among internet gamblers (AOR = 1.81; 95% CI: 1.03-3.19). Multivariate regression analyses indicated that among all characteristics of internet use assessed, utilizing the internet for the purposes of gambling practices was independently associated with problematic internet use among adolescents (AOR = 3.43; 95% CI: 1.40-8.39). Thus, the study findings suggest that adolescents who participate in internet gambling practices are more likely to concomitantly present with problematic internet use. PMID:20953681

  19. Scaffolding Dynamics and the Emergence of Problematic Learning Trajectories

    ERIC Educational Resources Information Center

    Steenbeek, Henderien; Jansen, Louise; van Geert, Paul

    2012-01-01

    This study aims at examining problematic learning trajectories of students with emotional behavioral disorders (EBD) by means of a longitudinal and time serial (micro genetic) study of individual instruction sessions during arithmetic lessons. Micro genetic analysis techniques were applied on the variable "responsiveness" in the scaffolding…

  20. A Grounded Theory of Counseling Students Who Report Problematic Peers

    ERIC Educational Resources Information Center

    Parker, Lindy K.; Chang, Catherine Y.; Corthell, Kimere K.; Walsh, Maggie E.; Brack, Greg; Grubbs, Natalie K.

    2014-01-01

    All counselors, including students, are responsible for intervening when a colleague shows signs of impairment. This grounded theory study investigated experiences of 12 counseling students who reported problematic peers. An emergent theory of the peer reporting process is presented, along with implications for counselor educators and suggestions…

  1. Goodbye Therapy: Use of Imagery Techniques for Problematic Grief Intervention.

    ERIC Educational Resources Information Center

    Brown, James C.

    This document addresses the issue of problematic grief reactions, reactions which tend to be more common than are often realized and which may be a source of "existential" anxiety. It presents a treatment model which can be used with any loss-elicited grief reaction including the acute grief reaction typically encountered subsequent to the death…

  2. The Validity and Reliability of the Problematic Internet Usage Scale

    ERIC Educational Resources Information Center

    Ceyhan, Esra; Ceyhan, Aydogan Aykut; Gurcan, Aysen

    2007-01-01

    In this research, it was aimed to develop an instrument for determining problematic internet usage of university students. Factorial structure of the data collected from 1658 university students revealed three factors. Of these, the first factor is called negative consequences of the internet and accounted for 25.36% of the variance, the second…

  3. The Effects of Meal Schedule and Quantity on Problematic Behavior.

    ERIC Educational Resources Information Center

    Wacker, David P.; And Others

    1996-01-01

    Two case examples (a toddler with severe developmental delays and a 7-year old with severe mental retardation) illustrating effects of meal schedule and food quantity on displays of problematic behavior are offered. Brief functional analyses of aberrant behavior provided useful information for interpreting distinct patterns of behavior. (DB)

  4. A Content Analysis of Problematic Behavior in Counselor Education Programs

    ERIC Educational Resources Information Center

    Brown, Maranda

    2013-01-01

    Counselor education programs are obligated by accreditation standards and professional codes of ethics to identify counselors-in-training whose academic, clinical, and personal performance indicate problematic behavior that would potentially prevent them from entering the profession (McAdams, Foster, & Ward, 2007; Rust, Raskin, & Hill,…

  5. The taxonicity of schizotypy: does the same taxonic class structure emerge from analyses of different attributes of schizotypy and from fundamentally different statistical methods?

    PubMed

    Linscott, Richard J

    2013-12-15

    Findings on the population distribution of schizotypy consistently point toward an underlying class structure. However, past research is methodologically homogeneous, chiefly involving analysis of attribute-specific indicators and coherent cut kinetic methods such as maximum covariance (MAXCOV) analysis. Two questions are examined. Are different or overlapping classes identified from different attributes of the schizophrenia phenotype? Do fundamentally different approaches to analysis yield consistent results? Participants (n=1074) completed the Schizotypal Personality Questionnaire (SPQ). Following item screening, MAXCOV analyses were conducted iteratively on attribute-specific item sets (cognitive-perceptual, interpersonal, and disorganized) and a general item set. Latent variable modeling (factor analysis, latent class analysis, and factor-mixture modeling) was used to examine the consistency of the MAXCOV results using items retained in the general set following MAXCOV analysis. Attribute-specific and general item sets gave taxonic MAXCOV curves and base rates of 8.4-10.4% and 3.6%, respectively. Classes were not independent. No latent variable model emerged as uniquely superior but five models distinguished a small high-scoring class populated by members of the MAXCOV general class. Different attributes distinguished overlapping yet nonredundant taxa, and a general schizotypy taxon identified with MAXCOV was also identified in latent variable modeling. PMID:23932839

  6. Dynamics of fire ant aggregations

    NASA Astrophysics Data System (ADS)

    Tennenbaum, Michael; Hu, David; Fernandez-Nieves, Alberto

    Fire ant aggregations are an inherently active system. Each ant harvests its own energy and can convert it into motion. The motion of individual ants contributes non-trivially to the bulk material properties of the aggregation. We have measured some of these properties using plate-plate rheology, where the response to an applied external force or deformation is measured. In this talk, we will present data pertaining to the aggregation behavior in the absence of any external force. We quantify the aggregation dynamics by monitoring the rotation of the top plate and by measuring the normal force. We then compare the results with visualizations of 2D aggregations.

  7. A cryptic taxon of Galápagos tortoise in conservation peril

    PubMed Central

    Russello, Michael A; Glaberman, Scott; Gibbs, James P; Marquez, Cruz; Powell, Jeffrey R; Caccone, Adalgisa

    2005-01-01

    As once boldly stated, ‘bad taxonomy can kill’, highlighting the critical importance of accurate taxonomy for the conservation of endangered taxa. The concept continues to evolve almost 15 years later largely because most legal protections aimed at preserving biological diversity are based on formal taxonomic designations. In this paper we report unrecognized genetic divisions within the giant tortoises of the Galápagos. We found three distinct lineages among populations formerly considered a single taxon on the most populous and accessible island of Santa Cruz; their diagnosability, degree of genetic divergence and phylogenetic placement merit the recognition of at least one new taxon. These results demonstrate the fundamental importance of continuing taxonomic investigations to recognize biological diversity and designate units of conservation, even within long-studied organisms such as Galápagos tortoises, whose evolutionary heritage and contribution to human intellectual history warrant them special attention. PMID:17148189

  8. Comparative genomics of Bifidobacterium animalis subsp. lactis reveals a strict monophyletic bifidobacterial taxon.

    PubMed

    Milani, Christian; Duranti, Sabrina; Lugli, Gabriele Andrea; Bottacini, Francesca; Strati, Francesco; Arioli, Stefania; Foroni, Elena; Turroni, Francesca; van Sinderen, Douwe; Ventura, Marco

    2013-07-01

    Strains of Bifidobacterium animalis subsp. lactis are extensively exploited by the food industry as health-promoting bacteria, although the genetic variability of members belonging to this taxon has so far not received much scientific attention. In this article, we describe the complete genetic makeup of the B. animalis subsp. lactis Bl12 genome and discuss the genetic relatedness of this strain with other sequenced strains belonging to this taxon. Moreover, a detailed comparative genomic analysis of B. animalis subsp. lactis genomes was performed, which revealed a closely related and isogenic nature of all currently available B. animalis subsp. lactis strains, thus strongly suggesting a closed pan-genome structure of this bacterial group. PMID:23645200

  9. MANAGING IMPORTED FIRE ANTS IN URBAN AREAS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The two species of imported fire ants (red imported fire ant, Solenopsis invicta, and black imported fire ant, Solenopsis richteri) and their sexually reproducing hybrid are invasive insects whose stings can cause serious medical problems. Imported fire ants interfere with outdoor activities and ha...

  10. Biological Control of Imported Fire Ants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 1998, the Alabama Fire Ant Management Program has been releasing natural enemies of imported fire ants. These natural enemies are being studied to determine their impact on fire ants. It is hoped that eventually the overall number of fire ants in Alabama can be reduced through biological cont...

  11. Use of cross-taxon congruence for hotspot identification at a regional scale.

    PubMed

    Fattorini, Simone; Dennis, Roger L H; Cook, Laurence M

    2012-01-01

    One of the most debated problems in conservation biology is the use of indicator (surrogate) taxa to predict spatial patterns in other taxa. Cross-taxon congruence in species richness patterns is of paramount importance at regional scales to disclose areas of high conservation value that are significant in a broader biogeographical context but yet placed in the finer, more practical, political context of decision making. We analysed spatial patterns of diversity in six arthropod taxa from the Turkish fauna as a regional case study relevant to global conservation of the Mediterranean basin. Although we found high congruence in cross-taxon comparisons of species richness (0.241taxon to capture diversity of other taxa was usually modest (on average, 50 percent of diversity of non-target taxa), limiting the use of hotspots for effective conservation of non-target groups. Nevertheless, our study demonstrates that a given group may partially stand in for another with similar ecological needs and biogeographical histories. We therefore advocate the use of multiple sets of taxa, chosen so as to be representative of animals with different ecological needs and biogeographical histories. PMID:22761947

  12. Merging ancient and modern DNA: extinct seabird taxon rediscovered in the North Tasman Sea.

    PubMed

    Steeves, Tammy E; Holdaway, Richard N; Hale, Marie L; McLay, Emma; McAllan, Ian A W; Christian, Margaret; Hauber, Mark E; Bunce, Michael

    2010-02-23

    Ancient DNA has revolutionized the way in which evolutionary biologists research both extinct and extant taxa, from the inference of evolutionary history to the resolution of taxonomy. Here, we present, to our knowledge, the first study to report the rediscovery of an 'extinct' avian taxon, the Tasman booby (Sula tasmani), using classical palaeontological data combined with ancient and modern DNA data. Contrary to earlier work, we show an overlap in size between fossil and modern birds in the North Tasman Sea (classified currently as S. tasmani and Sula dactylatra fullagari, respectively). In addition, we show that Holocene fossil birds have mitochondrial control region sequences that are identical to those found in modern birds. These results indicate that the Tasman booby is not an extinct taxon: S. dactylatra fullagari O'Brien & Davies, 1990 is therefore a junior synonym of Sula tasmani van Tets, Meredith, Fullagar & Davidson, 1988 and all North Tasman Sea boobies should be known as S. d. tasmani. In addition to reporting the rediscovery of an extinct avian taxon, our study highlights the need for researchers to be cognizant of multidisciplinary approaches to understanding taxonomy and past biodiversity. PMID:19675005

  13. Evidence of taxon cycles in an Indo-Pacific passerine bird radiation (Aves: Pachycephala)

    PubMed Central

    Jønsson, Knud Andreas; Irestedt, Martin; Christidis, Les; Clegg, Sonya M.; Holt, Ben G.; Fjeldså, Jon

    2014-01-01

    Many insular taxa possess extraordinary abilities to disperse but may differ in their abilities to diversify and compete. While some taxa are widespread across archipelagos, others have disjunct (relictual) populations. These types of taxa, exemplified in the literature by selections of unrelated taxa, have been interpreted as representing a continuum of expansions and contractions (i.e. taxon cycles). Here, we use molecular data of 35 out of 40 species of the avian genus Pachycephala (including 54 out of 66 taxa in Pachycephala pectoralis (sensu lato), to assess the spatio-temporal evolution of the group. We also include data on species distributions, morphology, habitat and elevational ranges to test a number of predictions associated with the taxon-cycle hypothesis. We demonstrate that relictual species persist on the largest and highest islands across the Indo-Pacific, whereas recent archipelago expansions resulted in colonization of all islands in a region. For co-occurring island taxa, the earliest colonists generally inhabit the interior and highest parts of an island, with little spatial overlap with later colonists. Collectively, our data support the idea that taxa continuously pass through phases of expansions and contractions (i.e. taxon cycles). PMID:24403319

  14. How territoriality and host-tree taxa determine the structure of ant mosaics

    NASA Astrophysics Data System (ADS)

    Dejean, Alain; Ryder, Suzanne; Bolton, Barry; Compin, Arthur; Leponce, Maurice; Azémar, Frédéric; Céréghino, Régis; Orivel, Jérôme; Corbara, Bruno

    2015-06-01

    Very large colonies of territorially dominant arboreal ants (TDAAs), whose territories are distributed in a mosaic pattern in the canopies of many tropical rainforests and tree crop plantations, have a generally positive impact on their host trees. We studied the canopy of an old Gabonese rainforest (ca 4.25 ha sampled, corresponding to 206 "large" trees) at a stage just preceding forest maturity (the Caesalpinioideae dominated; the Burseraceae were abundant). The tree crowns sheltered colonies from 13 TDAAs plus a co-dominant species out of the 25 ant species recorded. By mapping the TDAAs' territories and using a null model co-occurrence analysis, we confirmed the existence of an ant mosaic. Thanks to a large sampling set and the use of the self-organizing map algorithm (SOM), we show that the distribution of the trees influences the structure of the ant mosaic, suggesting that each tree taxon attracts certain TDAA species rather than others. The SOM also improved our knowledge of the TDAAs' ecological niches, showing that these ant species are ecologically distinct from each other based on their relationships with their supporting trees. Therefore, TDAAs should not systematically be placed in the same functional group even when they belong to the same genus. We conclude by reiterating that, in addition to the role played by TDAAs' territorial competition, host trees contribute to structuring ant mosaics through multiple factors, including host-plant selection by TDAAs, the age of the trees, the presence of extrafloral nectaries, and the taxa of the associated hemipterans.

  15. How territoriality and host-tree taxa determine the structure of ant mosaics.

    PubMed

    Dejean, Alain; Ryder, Suzanne; Bolton, Barry; Compin, Arthur; Leponce, Maurice; Azémar, Frédéric; Céréghino, Régis; Orivel, Jérôme; Corbara, Bruno

    2015-06-01

    Very large colonies of territorially dominant arboreal ants (TDAAs), whose territories are distributed in a mosaic pattern in the canopies of many tropical rainforests and tree crop plantations, have a generally positive impact on their host trees. We studied the canopy of an old Gabonese rainforest (ca 4.25 ha sampled, corresponding to 206 "large" trees) at a stage just preceding forest maturity (the Caesalpinioideae dominated; the Burseraceae were abundant). The tree crowns sheltered colonies from 13 TDAAs plus a co-dominant species out of the 25 ant species recorded. By mapping the TDAAs' territories and using a null model co-occurrence analysis, we confirmed the existence of an ant mosaic. Thanks to a large sampling set and the use of the self-organizing map algorithm (SOM), we show that the distribution of the trees influences the structure of the ant mosaic, suggesting that each tree taxon attracts certain TDAA species rather than others. The SOM also improved our knowledge of the TDAAs' ecological niches, showing that these ant species are ecologically distinct from each other based on their relationships with their supporting trees. Therefore, TDAAs should not systematically be placed in the same functional group even when they belong to the same genus. We conclude by reiterating that, in addition to the role played by TDAAs' territorial competition, host trees contribute to structuring ant mosaics through multiple factors, including host-plant selection by TDAAs, the age of the trees, the presence of extrafloral nectaries, and the taxa of the associated hemipterans. PMID:26004265

  16. Identification and assessment of problematic interpersonal situations for urban adolescents.

    PubMed

    Farrell, A D; Ampy, L A; Meyer, A L

    1998-10-01

    Identified and developed a scale to assess problematic interpersonal situations among urban adolescents. In Study 1, problematic situations were identified by focus groups of 6th graders (N = 43). Their relevance was verified in Study 2 by assessing their reported frequency and difficulty in a sample of 6th graders (N = 457) that included mostly African American youth from low-income families. Scales representing 3 dimensions, peer provocation, perceived injustice, and environmental stressors were verified by confirmatory factor analyses. In Study 3, the internal consistency and structure of these scales were cross-validated in a sample of 7th graders (N = 459). All 3 scales were correlated with self-reported violent behavior, drug use, and anxiety and uniquely accounted for 11% to 19% of the variance. These findings have implications for identifying youth at risk for emotional and behavioral problems and for designing more relevant interventions. PMID:9789189

  17. Cyberbullying, problematic internet use, and psychopathologic symptoms among Korean youth.

    PubMed

    Jung, Young-Eun; Leventhal, Bennett; Kim, Young Shin; Park, Tae Won; Lee, Sheen-Hoo; Lee, Myeongmi; Park, Seon Hee; Yang, Jong-Chul; Chung, Young-Chul; Chung, Sang-Keun; Park, Jong-Il

    2014-05-01

    To evaluate the associations between cyberbullying behaviors and problematic internet use, and to compare psychopathologic symptoms in victims, perpetrators, and victims-perpetrators of cyberbullying to those in youths who were not involved in cyberbullying. A total of 4531 youths (11-14 years of age) were recruited from elementary and middle schools. Among 4531 youths, 9.7% were involved in cyberbullying; 3.3% were only victims; 3.4% were only perpetrators; and 3.0% were victims-perpetrators. Cyberbullying behaviors were associated with problematic internet use as well as various psychopathologic symptoms. Depressive symptoms were associated with cyberbullying victimization, and rule-breaking behaviors and aggressive behaviors have relevance to cyberbullying perpetration. Greater attention needs to be paid to identify youths earlier who are involved in cyberbullying and prevent serious adverse consequences in them. PMID:24719154

  18. Cyberbullying, Problematic Internet Use, and Psychopathologic Symptoms among Korean Youth

    PubMed Central

    Jung, Young-Eun; Leventhal, Bennett; Kim, Young Shin; Lee, Sheen-Hoo; Lee, Myeongmi; Park, Seon Hee; Yang, Jong-Chul; Chung, Young-Chul; Chung, Sang-Keun; Park, Jong-Il

    2014-01-01

    To evaluate the associations between cyberbullying behaviors and problematic internet use, and to compare psychopathologic symptoms in victims, perpetrators, and victims-perpetrators of cyberbullying to those in youths who were not involved in cyberbullying. A total of 4531 youths (11-14 years of age) were recruited from elementary and middle schools. Among 4531 youths, 9.7% were involved in cyberbullying; 3.3% were only victims; 3.4% were only perpetrators; and 3.0% were victims-perpetrators. Cyberbullying behaviors were associated with problematic internet use as well as various psychopathologic symptoms. Depressive symptoms were associated with cyberbullying victimization, and rule-breaking behaviors and aggressive behaviors have relevance to cyberbullying perpetration. Greater attention needs to be paid to identify youths earlier who are involved in cyberbullying and prevent serious adverse consequences in them. PMID:24719154

  19. Emotional Openness, problematic eating behaviours, and overweight in adolescents.

    PubMed

    Walther, Mireille; Hilbert, Anja

    2015-04-01

    Overweight, a common health condition in adolescence, has been linked with difficulties in emotional processing. This study investigates associations between emotional processing, conceptualised through the model of Emotional Openness (EO), problematic eating behaviours, including Eating in the Absence of Hunger and disinhibited eating, and overweight in adolescents. Several self-report instruments were completed by 160 youngsters (mean age: 14.36±0.61years) from the community, including 39 overweight and obese adolescents (24.5%). In girls, bootstrap analyses supported a mediating effect of restrained eating on the relation between three EO dimensions and body mass index percentile, in particular the communication of emotions, the cognitive-conceptual representation of emotions, and the perception of bodily indicator of emotions. No mediating effect was found in boys. These results have important implications for psychological weight management interventions, as they underline the relevance of work on emotional processing in order to reduce problematic eating behaviours. PMID:25682365

  20. Analysis of self-reported problematic tasks for pregnant women.

    PubMed

    Cheng, P L; Dumas, G A; Smith, J T; Leger, A B; Plamondon, A; McGrath, M J; Tranmer, J E

    2006-02-22

    The objective of this study was to identify major components of, and influential factors in, problematic tasks performed by pregnant women employed in education, health care and service areas. Seventy-two pregnant women were surveyed using specially designed questionnaires consisting of an Initial Survey, a Job Analysis Questionnaire and a Task Description Questionnaire. Forty-four subjects (60%) had difficulty performing at least one work task and reported 105 tasks that were problematic at work. Reaching above the head, bending forward, bending and twisting, pushing, repeating actions and working at a fast pace were identified as the task components requiring the greatest level of effort. Excessive effort, excessive time, getting tired, repetitive actions, stress and fear of injury were identified as factors that had strong associations with the six major task components. Findings of this study suggest that these task components and factors should be considered when designing, assigning or analysing tasks for working pregnant women. PMID:16540440

  1. Neuroretinitis following bull ant sting.

    PubMed

    Ullrich, Katja; Saha, Niladri; Lake, Stewart

    2012-01-01

    Cat scratch disease causes the majority of cases of neuroretinitis. Neuroretinitis is characterised by clinical features of papillitis, macular oedema and macular star. We report a case study of infection with Bartonella henselae most likely transmitted by a bull ant sting. The patient presented with blurred vision and reduced visual acuity after being stung by an ant in her garden some 7 days earlier. Further testing revealed positive serology to B henselae and the patient improved with appropriate treatment. PMID:22865803

  2. Measuring activity in ant colonies

    NASA Astrophysics Data System (ADS)

    Noda, C.; Fernández, J.; Pérez-Penichet, C.; Altshuler, E.

    2006-12-01

    Ants, as paradigm of social insects, have become a recurrent example of efficient problem solvers via self-organization. In spite of the simple behavior of each individual, the colony as a whole displays "swarm intelligence:" the organization of ant trails for foraging is a typical output of it. But conventional techniques of observation can hardly record the amount of data needed to get a detailed understanding of self-organization of ant swarms in the wild. Here we are presenting a measurement system intended to monitor ant activity in the field comprising massive data acquisition and high sensitivity. A central role is played by an infrared sensor devised specifically to monitor relevant parameters to the activity of ants through the exits of the nest, although other sensors detecting temperature and luminosity are added to the system. We study the characteristics of the activity sensor and its performance in the field. Finally, we present massive data measured at one exit of a nest of Atta insularis, an ant endemic to Cuba, to illustrate the potential of our system.

  3. Trap-mulching Argentine ants.

    PubMed

    Silverman, Jules; Sorenson, Clyde E; Waldvogel, Michael G

    2006-10-01

    Argentine ant, Linepithema humile (Mayr), management is constrained, in large part, by polydomy where nestmates are distributed extensively across urban landscapes, particularly within mulch. Management with trap-mulching is a novel approach derived from trap-cropping where ants are repelled from a broad domain of nest sites to smaller defined areas, which are subsequently treated with insecticide. This concept was field-tested with mulch surrounding ornamental trees replaced with a narrow band of pine (Pinus spp.) needle mulch (trap) within a much larger patch of repellent aromatic cedar (Juniperus spp.) mulch. After ants reestablished around the trees, the pine needle mulch band was treated with 0.06% fipronil (Termidor). Poor results were obtained when the trap extended from the tree trunk to the edge of the mulched area. When the trap was applied as a circular band around the tree trunk reductions in the number of foraging ants were recorded through 14 d compared with an untreated mulch control, but not for longer periods. Reductions in the number of ant nests within mulch were no different between the trap mulch and any of the other treatments. We conclude that trap-mulching offers limited benefits, and that successful management of Argentine ants will require implementation of complementary or perhaps alternative strategies. PMID:17066809

  4. Childhood adversities and risk for problematic alcohol use.

    PubMed

    Dragan, Małgorzata; Hardt, Jochen

    2016-08-01

    The findings from studies exploring the relationship between childhood adversities (CAs) and adolescent and adult drinking problems are inconclusive - some researchers have found strong effects, others virtually none. In this study, we sought to examine the associations between 23 types of retrospectively reported CAs and adult problematic alcohol use in two samples, one drawn from Germany, the other from Poland. A total sample of 1008 participants was recruited via the internet: 500 in Germany and 508 in Poland. They completed a set of questionnaires including questions regarding various types of CA, and also the CAGE tool for the identification of problem drinking. CAs were grouped into four categories: Negative Personal Experience, Family Adversities, Parental Disorders, Parent-Child Relationships; this last category included role reversal. Separate logistic regression analyses were performed, with age, gender and country as potential confounders. The probability of having an alcohol problem was higher in men, and higher in Poland than in Germany. Of the risk factors tested, three displayed a significant association with problematic alcohol use. The risk factors concerned were Regular Arguments Between the Parents, plus two types of adversities from the Parent-Child Relationships cluster: Maternal Control and Maternal Role Reversal. The results serve to underline the importance of examining links between childhood risk factors and problematic alcohol use, and also suggest that certain less visible symptoms of a disordered parent-child (particularly mother-child) relationship, such as parentification, may constitute important risk factors for the development of drinking problems in later life. PMID:27082746

  5. A problematic early tetrapod from the Mississippian of Nevada

    USGS Publications Warehouse

    Thomson, K.S.; Shubin, N.S.; Poole, F.G.

    1998-01-01

    We report here the discovery of a new taxon of Paleozoic tetrapod from the Late Mississippian of Nevada (330-340 Ma). It has a unique vertebral column with principal centra having vertical anterior and posterior faces, ventrally incomplete accessory centra located antero-dorsally in each centrum, and enlarged presacral/sacral vertebrae. The head and pectoral girdle were not preserved but the large femur, robust pelvic girdle and enlarged sacral vertebrae possibly indicate a terrestrial mode of life. This new form significantly extends the western geographic range of known Mississippian tetrapods. It presents a mosaic of primitive and derived features, indicating that continued revision of traditional accounts of vertebral homology and the early diversifications of Paleozoic tetrapods will be necessary.

  6. Cyatta abscondita: Taxonomy, Evolution, and Natural History of a New Fungus-Farming Ant Genus from Brazil

    PubMed Central

    Sosa-Calvo, Jeffrey; Schultz, Ted R.; Brandão, Carlos R. F.; Klingenberg, Christiana; Feitosa, Rodrigo M.; Rabeling, Christian; Bacci, Maurício; Lopes, Cauê T.; Vasconcelos, Heraldo L.

    2013-01-01

    Cyatta abscondita, a new genus and species of fungus-farming ant from Brazil, is described based on morphological study of more than 20 workers, two dealate gynes, one male, and two larvae. Ecological field data are summarized, including natural history, nest architecture, and foraging behavior. Phylogenetic analyses of DNA sequence data from four nuclear genes indicate that Cyatta abscondita is the distant sister taxon of the genus Kalathomyrmex, and that together they comprise the sister group of the remaining neoattine ants, an informal clade that includes the conspicuous and well-known leaf-cutter ants. Morphologically, Cyatta abscondita shares very few obvious character states with Kalathomyrmex. It does, however, possess a number of striking morphological features unique within the fungus-farming tribe Attini. It also shares morphological character states with taxa that span the ancestral node of the Attini. The morphology, behavior, and other biological characters of Cyatta abscondita are potentially informative about plesiomorphic character states within the fungus-farming ants and about the early evolution of ant agriculture. PMID:24260403

  7. Monoculture of Leafcutter Ant Gardens

    PubMed Central

    Mueller, Ulrich G.; Scott, Jarrod J.; Ishak, Heather D.; Cooper, Michael; Rodrigues, Andre

    2010-01-01

    Background Leafcutter ants depend on the cultivation of symbiotic Attamyces fungi for food, which are thought to be grown by the ants in single-strain, clonal monoculture throughout the hundreds to thousands of gardens within a leafcutter nest. Monoculture eliminates cultivar-cultivar competition that would select for competitive fungal traits that are detrimental to the ants, whereas polyculture of several fungi could increase nutritional diversity and disease resistance of genetically variable gardens. Methodology/Principal Findings Using three experimental approaches, we assessed cultivar diversity within nests of Atta leafcutter ants, which are most likely among all fungus-growing ants to cultivate distinct cultivar genotypes per nest because of the nests' enormous sizes (up to 5000 gardens) and extended lifespans (10–20 years). In Atta texana and in A. cephalotes, we resampled nests over a 5-year period to test for persistence of resident cultivar genotypes within each nest, and we tested for genetic differences between fungi from different nest sectors accessed through excavation. In A. texana, we also determined the number of Attamyces cells carried as a starter inoculum by a dispersing queens (minimally several thousand Attamyces cells), and we tested for genetic differences between Attamyces carried by sister queens dispersing from the same nest. Except for mutational variation arising during clonal Attamyces propagation, DNA fingerprinting revealed no evidence for fungal polyculture and no genotype turnover during the 5-year surveys. Conclusions/Significance Atta leafcutter ants can achieve stable, fungal monoculture over many years. Mutational variation emerging within an Attamyces monoculture could provide genetic diversity for symbiont choice (gardening biases of the ants favoring specific mutational variants), an analog of artificial selection. PMID:20844760

  8. Macroevolutionary assembly of ant/plant symbioses: Pseudomyrmex ants and their ant-housing plants in the Neotropics.

    PubMed

    Chomicki, Guillaume; Ward, Philip S; Renner, Susanne S

    2015-11-22

    Symbioses include some of the clearest cases of coevolution, but their origin, loss or reassembly with different partners can rarely be inferred. Here we use ant/plant symbioses involving three plant clades to investigate the evolution of symbioses. We generated phylogenies for the big-eyed arboreal ants (Pseudomyrmecinae), including 72% of their 286 species, as well as for five of their plant host groups, in each case sampling more than 61% of the species. We show that the ant-housing Vachellia (Mimosoideae) clade and its ants co-diversified for the past 5 Ma, with some species additionally colonized by younger plant-nesting ant species, some parasitic. An apparent co-radiation of ants and Tachigali (Caesalpinioideae) was followed by waves of colonization by the same ant clade, and subsequent occupation by a younger ant group. Wide crown and stem age differences between the ant-housing genus Triplaris (Polygonaceae) and its obligate ant inhabitants, and stochastic trait mapping, indicate that its domatium evolved earlier than the ants now occupying it, suggesting previous symbioses that dissolved. Parasitic ant species evolved from generalists, not from mutualists, and are younger than the mutualistic systems they parasitize. Our study illuminates the macroevolutionary assembly of ant/plant symbioses, which has been highly dynamic, even in very specialized systems. PMID:26582029

  9. Evaluating and interpreting cross-taxon congruence: Potential pitfalls and solutions

    NASA Astrophysics Data System (ADS)

    Gioria, Margherita; Bacaro, Giovanni; Feehan, John

    2011-05-01

    Characterizing the relationship between different taxonomic groups is critical to identify potential surrogates for biodiversity. Previous studies have shown that cross-taxa relationships are generally weak and/or inconsistent. The difficulties in finding predictive patterns have often been attributed to the spatial and temporal scales of these studies and on the differences in the measure used to evaluate such relationships (species richness versus composition). However, the choice of the analytical approach used to evaluate cross-taxon congruence inevitably represents a major source of variation. Here, we described the use of a range of methods that can be used to comprehensively assess cross-taxa relationships. To do so, we used data for two taxonomic groups, wetland plants and water beetles, collected from 54 farmland ponds in Ireland. Specifically, we used the Pearson correlation and rarefaction curves to analyse patterns in species richness, while Mantel tests, Procrustes analysis, and co-correspondence analysis were used to evaluate congruence in species composition. We compared the results of these analyses and we described some of the potential pitfalls associated with the use of each of these statistical approaches. Cross-taxon congruence was moderate to strong, depending on the choice of the analytical approach, on the nature of the response variable, and on local and environmental conditions. Our findings indicate that multiple approaches and measures of community structure are required for a comprehensive assessment of cross-taxa relationships. In particular, we showed that selection of surrogate taxa in conservation planning should not be based on a single statistic expressing the degree of correlation in species richness or composition. Potential solutions to the analytical issues associated with the assessment of cross-taxon congruence are provided and the implications of our findings in the selection of surrogates for biodiversity are discussed.

  10. DNA Barcode Sequence Identification Incorporating Taxonomic Hierarchy and within Taxon Variability

    PubMed Central

    Little, Damon P.

    2011-01-01

    For DNA barcoding to succeed as a scientific endeavor an accurate and expeditious query sequence identification method is needed. Although a global multiple–sequence alignment can be generated for some barcoding markers (e.g. COI, rbcL), not all barcoding markers are as structurally conserved (e.g. matK). Thus, algorithms that depend on global multiple–sequence alignments are not universally applicable. Some sequence identification methods that use local pairwise alignments (e.g. BLAST) are unable to accurately differentiate between highly similar sequences and are not designed to cope with hierarchic phylogenetic relationships or within taxon variability. Here, I present a novel alignment–free sequence identification algorithm–BRONX–that accounts for observed within taxon variability and hierarchic relationships among taxa. BRONX identifies short variable segments and corresponding invariant flanking regions in reference sequences. These flanking regions are used to score variable regions in the query sequence without the production of a global multiple–sequence alignment. By incorporating observed within taxon variability into the scoring procedure, misidentifications arising from shared alleles/haplotypes are minimized. An explicit treatment of more inclusive terminals allows for separate identifications to be made for each taxonomic level and/or for user–defined terminals. BRONX performs better than all other methods when there is imperfect overlap between query and reference sequences (e.g. mini–barcode queries against a full–length barcode database). BRONX consistently produced better identifications at the genus–level for all query types. PMID:21857897

  11. Body weight prediction in early fossil hominids: towards a taxon-"independent" approach.

    PubMed

    Hartwig-Scherer, S

    1993-09-01

    The choice of a model taxon is crucial when investigating fossil hominids that clearly do not resemble any extant species (such as Australopithecus) or show significant differences from modern human proportions (such as Homo habilis OH 62). An "interhominoid" combination is not adequate either, as scaling with body weight is strongly divergent in African apes and humans for most skeletal predictors investigated here. Therefore, in relation to a study of seven long bone dimensions, a new taxon-"independent" approach is suggested. For a given predictor, its taxonomic "independence" is restricted to the size range over which the body weight-predictor relationship for African apes and humans converges. Different predictors produce converging body weight estimates (BWEs) for different size ranges: taxon-"independent" estimates can be calculated for small- and medium-sized hominids (e.g., for weights below 50 kg) using femoral and tibial dimensions, whereas upper limb bones provide converging results for large hominids (above 50 kg). If the remains of Australopithecus afarensis really belong to one species, the relationship of male (above 60 kg) to female body weight (approximately 30 kg) does not fall within the observed range of modern hominoids. Considering Sts 14 (22 kg) to represent a small-sized Australopithecus africanus, the level of encephalization lies well above that of extant apes. If OH 62 (approximately 25 kg), with limb proportions less human-like than those of australopithecines, indeed represents Homo habilis (which has been questioned previously), an increase in relative brain size would have occurred well before full bipedality, an assumption running counter to current assumptions concerning early human evolution. PMID:8238289

  12. How Ants Drop Out: Ant Abundance on Tropical Mountains

    PubMed Central

    Longino, John T.; Branstetter, Michael G.; Colwell, Robert K.

    2014-01-01

    In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica) and examined the impact of elevation (as a proxy for temperature) and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops. PMID:25098722

  13. Detrimental effects of highly efficient interference competition: invasive Argentine ants outcompete native ants at toxic baits.

    PubMed

    Buczkowski, Grzegorz; Bennett, Gary W

    2008-06-01

    The Argentine ant (Linepithema humile) is an invasive species that disrupts the balance of natural ecosystems by displacing indigenous ant species throughout its introduced range. Previous studies that examined the mechanisms by which Argentine ants attain ecological dominance showed that superior interference and exploitation competition are key to the successful displacement of native ant species. The objective of this research was to test the hypothesis that effective interference competition by Argentine ants may also be detrimental to the survival of Argentine ant colonies where Argentine ants and native ants compete at toxic baits used to slow the spread of Argentine ants. To study this hypothesis, we examined the competitive interactions between Argentine ants and native odorous house ants, Tapinoma sessile, in the presence and absence of toxic baits. Results showed that Argentine ants aggressively outcompete T. sessile from toxic baits through efficient interference competition and monopolize bait resources. This has severe negative consequences for the survival of Argentine ants as colonies succumb to the toxic effects of the bait. In turn, T. sessile avoid areas occupied by Argentine ants, give up baits, and consequently suffer minimal mortality. Our results provide experimental evidence that highly efficient interference competition may have negative consequences for Argentine ants in areas where toxic baits are used and may provide a basis for designing innovative management programs for Argentine ants. Such programs would have the double benefit of selectively eliminating the invasive species while simultaneously protecting native ants from the toxic effects of baits. PMID:18559180

  14. Psychiatry and ethics: the problematics of respect for religious meanings.

    PubMed

    Post, S G

    1993-09-01

    Over the past two decades American psychiatrists have had to address the emergence of an increasingly fervent religious pluralism. Particularly in cases of socially controversial new religious movements (NRMs), distressed families have pressured psychiatrists to assess the mental state of recruits to such sects, often labeled "cults." At this inevitably acrimonious interface between family values and religious liberties, psychiatrists have for the most part resisted pressures to medicalize religious conversions. This article provides an historical review of American psychiatric response to NRMs with respect to nosology and practice. It introduces this response in the more general context of ethics and the problematics of respect for religious meanings. PMID:8269715

  15. Possible problematic situations for the Europa cryorobotic mission

    NASA Astrophysics Data System (ADS)

    Kereszturi, A.

    We analyzed some possible dangerous and problematic situations which can take place during the descend of the Europa exlporer cryorobot inside the ice crust. Our work summarizing the followings: 1. consequences of the differences in the ice thickness and time of descend based on our and other workers' ice thickness estimations, 2. consequences of the tectonic movements in the crust during the descend of the cryorobot, 3. consequences of salt rich diapiric/cryomagmatic intrusions on the descend of the probe, 4. consequences of liquid water bodies inside the ice crust during the descend, 5. usage of the whole cryorobot below the ice crust as a robotic submarine.

  16. Do aphids actively search for ant partners?

    PubMed

    Fischer, Christophe Y; Vanderplanck, Maryse; Lognay, Georges C; Detrain, Claire; Verheggen, François J

    2015-04-01

    The aphid-ant mutualistic relationships are not necessarily obligate for neither partners but evidence is that such interactions provide them strong advantages in terms of global fitness. While it is largely assumed that ants actively search for their mutualistic partners namely using volatile cues; whether winged aphids (i.e., aphids' most mobile form) are able to select ant-frequented areas had not been investigated so far. Ant-frequented sites would indeed offer several advantages for these aphids including a lower predation pressure through ant presence and enhanced chances of establishing mutuaslistic interactions with neighbor ant colonies. In the field, aphid colonies are often observed in higher densities around ant nests, which is probably linked to a better survival ensured by ants' services. Nevertheless, this could also result from a preferential establishment of winged aphids in ant-frequented areas. We tested this last hypothesis through different ethological assays and show that the facultative myrmecophilous black bean aphid, Aphis fabae L., does not orientate its search for a host plant preferentially toward ant-frequented plants. However, our results suggest that ants reduce the number of winged aphids leaving the newly colonized plant. Thus, ants involved in facultative myrmecophilous interactions with aphids appear to contribute to structure aphid populations in the field by ensuring a better establishment and survival of newly established colonies rather than by inducing a deliberate plant selection by aphid partners based on the proximity of ant colonies. PMID:24659520

  17. Myrmecotrophy: Plants fed by ants.

    PubMed

    Beattie, A

    1989-06-01

    Two plant genera with tubers specialized for occupation by ants absorb nutrients from waste materials accumulated by the resident colonies. The mineral resources of these host plants are augmented by colony foraging which functions as a second root system. This mutualistic interaction has become known as myrmecotrophy. Many other kinds of plant structure are apparent adaptations to accommodate ant colonies; these include pouches on leaves or petioles and hollow twigs, stems or thorns. Sometimes the ant species residing in these structures are aggressive towards enemies of the host plant and are important for plant defence. Recent research provides some evidence that myrmecotrophy may have a wider role in plant nutrition, at least when subsidizing the costs of plant defence. PMID:21227344

  18. Presence of the fire ant pathogen Kneallhazia solenopsae in fire ant decapitating phorid flies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pathogens and parasites from South America are being evaluated for the biological control of imported fire ants in the U.S. Fire ant decapitating flies that developed in fire ants infected with the fire ant pathogen Kneallhazia (formerly Thelohania) solenopsae also acquired the pathogen. K. soleno...

  19. The problematization of medical tourism: a critique of neoliberalism.

    PubMed

    Smith, Kristen

    2012-04-01

    The past two decades have seen the extensive privatisation and marketisation of health care in an ever reaching number of developing countries. Within this milieu, medical tourism is being promoted as a rational economic development strategy for some developing nations, and a makeshift solution to the escalating waiting lists and exorbitant costs of health care in developed nations. This paper explores the need to problematize medical tourism in order to move beyond one dimensional neoliberal discourses that have, to date, dominated the arena. In this problematization, the paper discusses a range of understandings and uses of the term 'medical tourism' and situates it within the context of the neoliberal economic development of health care internationally. Drawing on theory from critical medical anthropology and health and human rights perspectives, the paper critically analyzes the assumed independence between the medical tourism industry and local populations facing critical health issues, where social, cultural and economic inequities are widening in terms of access, cost and quality of health care. Finally, medical tourism is examined in the local context of India, critiquing the increasingly indistinct roles played by government and private sectors, whilst linking these shifts to global market forces. PMID:22420447

  20. Problematic Online Pornography Use: A Media Attendance Perspective.

    PubMed

    Sirianni, Joseph M; Vishwanath, Arun

    2016-01-01

    Since the rise of the popularity of the Internet, the accessibility of pornography has been a growing concern. One particular concern is the potential risk for addictive behaviors to occur as a result of the ease of viewing online pornographic material. The research presented herein explored online pornography addiction using a media attendance perspective, which allows media critics to examine the needs that people seek to fulfill from engaging with various media. Past studies that have used a media attendance perspective to explore media addiction, rephrased here as problematic media use, have done so using social cognitive theory and the concept of deficient self-regulation. Deficient self-regulation may be experienced by all media consumers and can range from normally impulsive media choices to pathological media choices which may result in detrimental life consequences. Borrowing from this, the current study reevaluated online pornography addiction using deficient self-regulation within a sociocognitive framework of media attendance. Results of our model show deficient self-regulation influences habitual online pornography consumption. Moreover, online pornography use motivated by social needs is perpetuated by deficient self-regulation and may lead to negative life consequences in some individuals. These findings contribute a new perspective and framework for understanding problematic online pornography use. PMID:25621631

  1. Political power beyond the State: problematics of government. 1992.

    PubMed

    Rose, Nikolas; Miller, Peter

    2010-01-01

    This paper sets out an approach to the analysis of political power in terms of problematics of government. It argues against an overvaluation of the 'problem of the State' in political debate and social theory. A number of conceptual tools are suggested for the analysis of the many and varied alliances between political and other authorities that seek to govern economic activity, social life and individual conduct. Modern political rationalities and governmental technologies are shown to be intrinsically linked to developments in knowledge and to the powers of expertise. The characteristics of liberal problematics of government are investigated, and it is argued that they are dependent upon technologies for 'governing at a distance', seeking to create locales, entities and persons able to operate a regulated autonomy. The analysis is exemplified through an investigation of welfarism as a mode of 'social' government. The paper concludes with a brief consideration of neo-liberalism which demonstrates that the analytical language structured by the philosophical opposition of state and civil society is unable to comprehend contemporary transformations in modes of exercise of political power.(1). PMID:20092498

  2. Monitoring the Impact of Solution Concepts within a Given Problematic

    NASA Astrophysics Data System (ADS)

    Cavallucci, Denis; Rousselot, François; Zanni, Cecilia

    It is acknowledged that one of the most critical issues facing today’s organizations concerns the substantial leaps required to methodologically structure innovation. Among other published work, some suggest that a complete rethinking of current practices is required. In this article, we propose a methodology aiming at providing controlled R&D choices based on a monitoring of the impact Solution Concepts provoke on a problematic situation. Initially this problematic situation is modeled in a graph form, namely a Problem Graph. It has the objective to assists R&D managers when choosing which activities to support and bring them concrete arguments to defend their choices. We postulate that by improving the robustness of such approaches we help deciders to switch from intuitive decisions (mostly built upon their past experiences, fear regarding risks, and awareness of the company’s level of acceptance of novelties) to thoroughly constructed inventive problem solving strategies. Our approach will be discussed using a computer application that illustrates our hypothesis after being tested in several industrial applications.

  3. Detection and Polarization of Introgression in a Five-Taxon Phylogeny.

    PubMed

    Pease, James B; Hahn, Matthew W

    2015-07-01

    When multiple speciation events occur rapidly in succession, discordant genealogies due to incomplete lineage sorting (ILS) can complicate the detection of introgression. A variety of methods, including the [Formula: see text]-statistic (a.k.a. the "ABBA-BABA test"), have been proposed to infer introgression in the presence of ILS for a four-taxon clade. However, no integrated method exists to detect introgression using allelic patterns for more complex phylogenies. Here we explore the issues associated with previous systems of applying [Formula: see text]-statistics to a larger tree topology, and propose new [Formula: see text] tests as an integrated framework to infer both the taxa involved in and the direction of introgression for a symmetric five-taxon phylogeny. Using theory and simulations, we show that the [Formula: see text] statistics correctly identify the introgression donor and recipient lineages, even at low rates of introgression. [Formula: see text] is also shown to have extremely low false-positive rates. The [Formula: see text] tests are computationally inexpensive to calculate and can easily be applied to phylogenomic data sets, both genome-wide and in windows of the genome. In addition, we explore both the principles and problems of introgression detection in even more complex phylogenies. PMID:25888025

  4. Delineating Species with DNA Barcodes: A Case of Taxon Dependent Method Performance in Moths

    PubMed Central

    Kekkonen, Mari; Mutanen, Marko; Kaila, Lauri; Nieminen, Marko; Hebert, Paul D. N.

    2015-01-01

    The accelerating loss of biodiversity has created a need for more effective ways to discover species. Novel algorithmic approaches for analyzing sequence data combined with rapidly expanding DNA barcode libraries provide a potential solution. While several analytical methods are available for the delineation of operational taxonomic units (OTUs), few studies have compared their performance. This study compares the performance of one morphology-based and four DNA-based (BIN, parsimony networks, ABGD, GMYC) methods on two groups of gelechioid moths. It examines 92 species of Finnish Gelechiinae and 103 species of Australian Elachistinae which were delineated by traditional taxonomy. The results reveal a striking difference in performance between the two taxa with all four DNA-based methods. OTU counts in the Elachistinae showed a wider range and a relatively low (ca. 65%) OTU match with reference species while OTU counts were more congruent and performance was higher (ca. 90%) in the Gelechiinae. Performance rose when only monophyletic species were compared, but the taxon-dependence remained. None of the DNA-based methods produced a correct match with non-monophyletic species, but singletons were handled well. A simulated test of morphospecies-grouping performed very poorly in revealing taxon diversity in these small, dull-colored moths. Despite the strong performance of analyses based on DNA barcodes, species delineated using single-locus mtDNA data are best viewed as OTUs that require validation by subsequent integrative taxonomic work. PMID:25849083

  5. 'Candidatus Phytoplasma malaysianum', a novel taxon associated with virescence and phyllody of Madagascar periwinkle (Catharanthus roseus).

    PubMed

    Nejat, Naghmeh; Vadamalai, Ganesan; Davis, Robert E; Harrison, Nigel A; Sijam, Kamaruzaman; Dickinson, Matthew; Abdullah, Siti Nor Akmar; Zhao, Yan

    2013-02-01

    This study addressed the taxonomic position and group classification of a phytoplasma responsible for virescence and phyllody symptoms in naturally diseased Madagascar periwinkle plants in western Malaysia. Unique regions in the 16S rRNA gene from the Malaysian periwinkle virescence (MaPV) phytoplasma distinguished the phytoplasma from all previously described 'Candidatus Phytoplasma' species. Pairwise sequence similarity scores, calculated through alignment of full-length 16S rRNA gene sequences, revealed that the MaPV phytoplasma 16S rRNA gene shared 96.5 % or less sequence similarity with that of previously described 'Ca. Phytoplasma' species, justifying the recognition of the MaPV phytoplasma as a reference strain of a novel taxon, 'Candidatus Phytoplasma malaysianum'. The 16S rRNA gene F2nR2 fragment from the MaPV phytoplasma exhibited a distinct restriction fragment length polymorphism (RFLP) profile and the pattern similarity coefficient values were lower than 0.85 with representative phytoplasmas classified in any of the 31 previously delineated 16Sr groups; therefore, the MaPV phytoplasma was designated a member of a new 16Sr group, 16SrXXXII. Phytoplasmas affiliated with this novel taxon and the new group included diverse strains infecting periwinkle, coconut palm and oil palm in Malaysia. Three phytoplasmas were characterized as representatives of three distinct subgroups, 16SrXXXII-A, 16SrXXXII-B and 16SrXXXII-C, respectively. PMID:22523165

  6. Biological control of red imported fire ants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two species of Imported Fire Ants (IFA), the Red Imported Fire Ant, Solenopsis invicta Buren, and the Black Imported Fire Ant, S. richteri Forel, were introduced into the United States in the early 1900s and currently inhabit over 320 million acres in the southern United States and Puerto Rico. Red ...

  7. Using Ants To Investigate the Environment.

    ERIC Educational Resources Information Center

    Hagevik, Rita A.

    2003-01-01

    Describes three inquiry-based activities designed for students to begin to understand complex environmental relationships in their own backyard. Includes investigations of ants, which allow students to establish a baseline survey of ant fauna, test the importance of ants in nutrient cycling and soil structure maintenances, and increase student…

  8. Using Ants to Investigate the Environment

    ERIC Educational Resources Information Center

    Hagevik, Rita A.

    2005-01-01

    The best place for students to begin to understand complex environmental relationships is in their own back yards. Doing investigations of ants allows students to establish a baseline survey of ant fauna, test the importance of ants in nutrient cycling and soil structure maintenance, and increase their understanding of the environment and their…

  9. Raves & rants about invasive crazy ants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crazy ants” is a name that refers to various species of ants that are characterized by erratic, scurrying, or running, behavior when disturbed. Two of these species, the yellow crazy ant and the Caribbean or Rasberry [sic] crazy ant, are invasive with extremely large populations that inundate lands...

  10. Problematizing Disciplinarity, Transdisciplinary Problematics

    PubMed Central

    2015-01-01

    This article situates current debates about transdisciplinarity within the deeper history of academic disciplinarity, in its difference from the notions of inter- and multi-disciplinarity. It offers a brief typology and history of established conceptions of transdisciplinarity within science and technology studies. It then goes on to raise the question of the conceptual structure of transdisciplinary generality in the humanities, with respect to the incorporation of the 19th- and 20th-century German and French philosophical traditions into the anglophone humanities, under the name of ‘theory’. It identifies two distinct – dialectical and anti-dialectical, or dialectical and transversal – transdisciplinary trajectories. It locates the various contributions to the special issue of which it is the introduction within this conceptual field, drawing attention to the distinct contribution of the French debates about structuralism and its aftermath – those by Serres, Foucault, Derrida, Guattari and Latour, in particular. It concludes with an appendix on Foucault’s place within current debates about disciplinarity and academic disciplines. PMID:26456992

  11. Ants, Wasps, and Bees (Hymenoptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stinging wasps, bees, and ants are a problem for farm workers, particularly at harvest when these insects are attracted to ripe fruits. Researchers at the USDA-ARS Yakima Agricultural Research Laboratory, Wapato, WA, together with personnel at Oral Roberts University compiled available information o...

  12. Ant Ecdysteroid Extraction and Radioimmunoassay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecdysteroids are a group of steroid compounds present in many plant and invertebrate species. In arthropods, they function primarily as hormones involved in the regulation of molting. This protocol describes how to extract ecdysteroid hormones from ant specimens and subsequently quantify circulating...

  13. Evolutional Ant Colony Method Using PSO

    NASA Astrophysics Data System (ADS)

    Morii, Nobuto; Aiyoshi, Eitarou

    The ant colony method is one of heuristic methods capable of solving the traveling salesman problem (TSP), in which a good tour is generated by the artificial ant's probabilistic behavior. However, the generated tour length depends on the parameter describing the ant's behavior, and the best parameters corresponding to the problem to be solved is unknown. In this technical note, the evolutional strategy is presented to find the best parameter of the ant colony by using Particle Swarm Optimization (PSO) in the parameter space. Numerical simulations for benchmarks demonstrate effectiveness of the evolutional ant colony method.

  14. Tournaments and slavery in a desert ant.

    PubMed

    Hölldobler, B

    1976-05-28

    Many species of ants engage in physical fighting when territorial borders are challenged. In contrast, colonies of the honeypot ant species Myrmecocystus mimicus conduct ritualized tournaments, in which hundreds of ants perform highly stereotyped display fights. Opposing colonies summon their worker forces to the tournament area by means of an alarm-recruitment system. When one colony is considerably stronger than the other, the tournament quickly ends, and the weaker colony is raided and its ants "enslaved." This is the first example of intraspecific slavery recorded in ants. PMID:17817765

  15. Methods for Casting Subterranean Ant Nests

    PubMed Central

    Tschinkel, Walter R.

    2010-01-01

    The study of subterranean ant nests has been impeded by the difficulty of rendering their structures in visible form. Here, several different casting materials are shown to make perfect casts of the underground nests of ants. Each material (dental plaster, paraffin wax, aluminum, zinc) has advantages and limitations, which are discussed. Some of the materials allow the recovery of the ants entombed in the casts, allowing a census of the ants to be connected with features of their nest architecture. The necessary equipment and procedures are described in the hope that more researchers will study this very important aspect of ant natural history. PMID:20673073

  16. Measuring and analyzing the causes of problematic Internet use.

    PubMed

    Chiang, I-Ping; Su, Yung-Hsiang

    2012-11-01

    Since Internet surfing became a daily activity, people have changed their behavior. This research analyzes the causes of problematic Internet use through an online survey, where 1,094 samples were collected. Based on the results of structural equation modeling analysis, the following conclusions are reached: First, novelty, security, and efficiency increase users' online trust. Second, information and efficiency enhance users' sharing and anonymity online. Third, greater trust in Internet environments leads to an increase in a user's cognitive bias toward online behavioral responsibility and Internet addiction. Fourth, a user's attitude toward online sharing further increases the cognitive bias toward online copyright. Fifth, a user's attitude toward anonymity increases cognitive bias toward online copyright, online behavioral responsibility, and deepens Internet addiction. PMID:23020742

  17. [Reducing problematic sickness absence: of importance to every general practitioner].

    PubMed

    Wind, H; Opstelten, W; Hendriks, A C

    2016-01-01

    Problematic sickness absence is an issue that concerns not only occupational health physicians, but all physicians. More collaboration between occupational health and treating physicians, plus improved alignment of symptom treatment and reintegration counselling, can help avoid long-term sickness absence of employees. Achieving this goal presupposes mutual knowledge of each other's professions. Medical practice guidelines are a tool par excellence to share knowledge and bring this into practice. Treating physicians should not refrain from posing work-related and return-to-work questions, even if the overall responsibility lies with the occupational health physicians in terms of reintegration efforts. The patient's interest should be the leading principle for all physicians involved. This means not only provision of good care, aimed at patient recovery, but also adequate reintegration in the labour market. Occupational health physicians, general practitioners and consultant specialists should share this common goal. PMID:27299497

  18. At-Risk/Problematic Shopping and Gambling in Adolescence.

    PubMed

    Yip, Sarah W; Mei, Songli; Pilver, Corey E; Steinberg, Marvin A; Rugle, Loreen J; Krishnan-Sarin, Suchitra; Hoff, Rani A; Potenza, Marc N

    2015-12-01

    Elevated levels of both pathological gambling (PG) and problem shopping (PS) have been reported among adolescents, and each is associated with a range of other negative health/functioning measures. However, relationships between PS and PG, particularly during adolescence, are not well understood. In this study, we explored the relationship between different levels of problem-gambling severity and health/functioning characteristics, gambling-related social experiences, gambling behaviors and motivations among adolescents with and without at-risk/problematic shopping (ARPS). Survey data from Connecticut high school students (n = 2,100) were analyzed using bivariate analyses and logistic regression modeling. Although at-risk/problematic gambling (ARPG) was not increased among adolescents with ARPS, adolescents with ARPG (vs non-gamblers) were more likely to report having experienced a growing tension or anxiety that could only be relieved by shopping and missing other obligations due to shopping. In comparison to the non-ARPS group, a smaller proportion of respondents in the ARPS group reported paid part-time employment, whereas a greater proportion of respondents reported excessive gambling by peers and feeling concerned over the gambling of a close family member. In general, similar associations between problem-gambling severity and measures of health/functioning and gambling-related behaviors and motivations were observed across ARPS and non-ARPS adolescents. However, associations were weaker among ARPS adolescents for several variables: engagement in extracurricular activities, alcohol and caffeine use and gambling for financial reasons. These findings suggest a complex relationship between problem-gambling severity and ARPS. They highlight the importance of considering co-occurring risk behaviors such as ARPS when treating adolescents with at-risk/problem gambling. PMID:25117852

  19. Quantifying Ant Activity Using Vibration Measurements

    PubMed Central

    Oberst, Sebastian; Baro, Enrique Nava; Lai, Joseph C. S.; Evans, Theodore A.

    2014-01-01

    Ant behaviour is of great interest due to their sociality. Ant behaviour is typically observed visually, however there are many circumstances where visual observation is not possible. It may be possible to assess ant behaviour using vibration signals produced by their physical movement. We demonstrate through a series of bioassays with different stimuli that the level of activity of meat ants (Iridomyrmex purpureus) can be quantified using vibrations, corresponding to observations with video. We found that ants exposed to physical shaking produced the highest average vibration amplitudes followed by ants with stones to drag, then ants with neighbours, illuminated ants and ants in darkness. In addition, we devised a novel method based on wavelet decomposition to separate the vibration signal owing to the initial ant behaviour from the substrate response, which will allow signals recorded from different substrates to be compared directly. Our results indicate the potential to use vibration signals to classify some ant behaviours in situations where visual observation could be difficult. PMID:24658467

  20. The influence of taxon sampling on Bayesian divergence time inference under scenarios of rate heterogeneity among lineages.

    PubMed

    Soares, André E R; Schrago, Carlos G

    2015-01-01

    Although taxon sampling is commonly considered an important issue in phylogenetic inference, it is rarely considered in the Bayesian estimation of divergence times. In fact, the studies conducted to date have presented ambiguous results, and the relevance of taxon sampling for molecular dating remains unclear. In this study, we developed a series of simulations that, after six hundred Bayesian molecular dating analyses, allowed us to evaluate the impact of taxon sampling on chronological estimates under three scenarios of among-lineage rate heterogeneity. The first scenario allowed us to examine the influence of the number of terminals on the age estimates based on a strict molecular clock. The second scenario imposed an extreme example of lineage specific rate variation, and the third scenario permitted extensive rate variation distributed along the branches. We also analyzed empirical data on selected mitochondrial genomes of mammals. Our results showed that in the strict molecular-clock scenario (Case I), taxon sampling had a minor impact on the accuracy of the time estimates, although the precision of the estimates was greater with an increased number of terminals. The effect was similar in the scenario (Case III) based on rate variation distributed among the branches. Only under intensive rate variation among lineages (Case II) taxon sampling did result in biased estimates. The results of an empirical analysis corroborated the simulation findings. We demonstrate that taxonomic sampling affected divergence time inference but that its impact was significant if the rates deviated from those derived for the strict molecular clock. Increased taxon sampling improved the precision and accuracy of the divergence time estimates, but the impact on precision is more relevant. On average, biased estimates were obtained only if lineage rate variation was pronounced. PMID:25218869

  1. Taxon interactions control the distributions of cryoconite bacteria colonizing a High Arctic ice cap.

    PubMed

    Gokul, Jarishma K; Hodson, Andrew J; Saetnan, Eli R; Irvine-Fynn, Tristram D L; Westall, Philippa J; Detheridge, Andrew P; Takeuchi, Nozomu; Bussell, Jennifer; Mur, Luis A J; Edwards, Arwyn

    2016-08-01

    Microbial colonization of glacial ice surfaces incurs feedbacks which affect the melting rate of the ice surface. Ecosystems formed as microbe-mineral aggregates termed cryoconite locally reduce ice surface albedo and represent foci of biodiversity and biogeochemical cycling. Consequently, greater understanding the ecological processes in the formation of functional cryoconite ecosystems upon glacier surfaces is sought. Here, we present the first bacterial biogeography of an ice cap, evaluating the respective roles of dispersal, environmental and biotic filtration occurring at local scales in the assembly of cryoconite microbiota. 16S rRNA gene amplicon semiconductor sequencing of cryoconite colonizing a Svalbard ice cap coupled with digital elevation modelling of physical parameters reveals the bacterial community is dominated by a ubiquitous core of generalist taxa, with evidence for a moderate pairwise distance-decay relationship. While geographic position and melt season duration are prominent among environmental predictors of community structure, the core population of taxa appears highly influential in structuring the bacterial community. Taxon co-occurrence network analysis reveals a highly modular community structured by positive interactions with bottleneck taxa, predominantly Actinobacteria affiliated to isolates from soil humus. In contrast, the filamentous cyanobacterial taxon (assigned to Leptolyngbya/Phormidesmis pristleyi) which dominates the community and binds together granular cryoconite are poorly connected to other taxa. While our study targeted one ice cap, the prominent role of generalist core taxa with close environmental relatives across the global cryosphere indicate discrete roles for cosmopolitan Actinobacteria and Cyanobacteria as respective keystone taxa and ecosystem engineers of cryoconite ecosystems colonizing ice caps. PMID:27261672

  2. Macrochaete gen. nov. (Nostocales, Cyanobacteria), a taxon morphologically and molecularly distinct from Calothrix.

    PubMed

    Berrendero Gómez, Esther; Johansen, Jeffrey R; Kaštovský, Jan; Bohunická, Markéta; Čapková, Kateřina

    2016-08-01

    Historically, the genus Calothrix included all noncolonial, tapered, heterocytous filaments within the cyanobacteria. However, recent molecular phylogenies show that "Calothrix" defined in this sense represents five distinct clades. The type species of Calothrix is marine, with solitary basal heterocytes, no akinetes, and distal ends tapering abruptly into short hairs. We examined the morphology and phylogeny of 45 tapering cyanobacteria in the Rivulariaceae, including freshwater and marine representatives of both Calothrix (35 strains) and its sister taxon Rivularia (10 strains). The marine Calothrix fall into two lineages, but we lack the generitype and so cannot identify the clade corresponding to the type species. The freshwater and soil Calothrix fall into the C. parietina clade and are characterized by having a basal heterocyte, no akinetes, and gradual tapering-but not into a long hyaline hair. Macrochaete gen. nov. is a freshwater taxon sister to the Calothrix lineages but clearly separated from Rivularia. The species in this genus differ morphologically from Calothrix by their ability to produce two heteromorphic basal heterocytes and specific secondary structures of the 16S-23S ITS. An additional feature present in most species is the presence of a distal, long hyaline hair, but this character has incomplete penetrance due to its expression only under specific environmental conditions (low phosphate), and in one species appears to be lost. We recognize three species: M. psychrophila (type species) from cold environments (high mountains, Antarctica), M. santannae from wet walls of subtropical South America, and M. lichenoides, a phycobiont of lichens from Europe. PMID:27136320

  3. On the Complexity of the Saccharomyces bayanus Taxon: Hybridization and Potential Hybrid Speciation

    PubMed Central

    Pérez-Través, Laura; Lopes, Christian A.; Querol, Amparo; Barrio, Eladio

    2014-01-01

    Although the genus Saccharomyces has been thoroughly studied, some species in the genus has not yet been accurately resolved; an example is S. bayanus, a taxon that includes genetically diverse lineages of pure and hybrid strains. This diversity makes the assignation and classification of strains belonging to this species unclear and controversial. They have been subdivided by some authors into two varieties (bayanus and uvarum), which have been raised to the species level by others. In this work, we evaluate the complexity of 46 different strains included in the S. bayanus taxon by means of PCR-RFLP analysis and by sequencing of 34 gene regions and one mitochondrial gene. Using the sequence data, and based on the S. bayanus var. bayanus reference strain NBRC 1948, a hypothetical pure S. bayanus was reconstructed for these genes that showed alleles with similarity values lower than 97% with the S. bayanus var. uvarum strain CBS 7001, and of 99–100% with the non S. cerevisiae portion in S. pastorianus Weihenstephan 34/70 and with the new species S. eubayanus. Among the S. bayanus strains under study, different levels of homozygosity, hybridization and introgression were found; however, no pure S. bayanus var. bayanus strain was identified. These S. bayanus hybrids can be classified into two types: homozygous (type I) and heterozygous hybrids (type II), indicating that they have been originated by different hybridization processes. Therefore, a putative evolutionary scenario involving two different hybridization events between a S. bayanus var. uvarum and unknown European S. eubayanus-like strains can be postulated to explain the genomic diversity observed in our S. bayanus var. bayanus strains. PMID:24705561

  4. Development of taxon-specific sequences of common wheat for the detection of genetically modified wheat.

    PubMed

    Iida, Mayu; Yamashiro, Satomi; Yamakawa, Hirohito; Hayakawa, Katsuyuki; Kuribara, Hideo; Kodama, Takashi; Furui, Satoshi; Akiyama, Hiroshi; Maitani, Tamio; Hino, Akihiro

    2005-08-10

    Qualitative and quantitative Polymerase Chain Reaction (PCR) systems aimed at the specific detection and quantification of common wheat DNA are described. Many countries have issued regulations to label foods that include genetically modified organisms (GMOs). PCR technology is widely recognized as a reliable and useful technique for the qualitative and quantitative detection of GMOs. Detection methods are needed to amplify a target GM gene, and the amplified results should be compared with those of the corresponding taxon-specific reference gene to obtain reliable results. This paper describes the development of a specific DNA sequence in the waxy-D1 gene for common wheat (Triticum aestivum L.) and the design of a specific primer pair and TaqMan probe on the waxy-D1 gene for PCR analysis. The primers amplified a product (Wx012) of 102 bp. It is indicated that the Wx012 DNA sequence is specific to common wheat, showing homogeneity in qualitative PCR results and very similar quantification accuracy along 19 distantly related common wheat varieties. In Southern blot and real-time PCR analyses, this sequence showed either a single or a low number of copy genes. In addition, by qualitative and quantitative PCR using wx012 primers and a wx012-T probe, the limits of detection of the common wheat genome were found to be about 15 copies, and the reproducibility was reliable. In consequence, the PCR system using wx012 primers and wx012-T probe is considered to be suitable for use as a common wheat-specific taxon-specific reference gene in DNA analyses, including GMO tests. PMID:16076109

  5. On the complexity of the Saccharomyces bayanus taxon: hybridization and potential hybrid speciation.

    PubMed

    Pérez-Través, Laura; Lopes, Christian A; Querol, Amparo; Barrio, Eladio

    2014-01-01

    Although the genus Saccharomyces has been thoroughly studied, some species in the genus has not yet been accurately resolved; an example is S. bayanus, a taxon that includes genetically diverse lineages of pure and hybrid strains. This diversity makes the assignation and classification of strains belonging to this species unclear and controversial. They have been subdivided by some authors into two varieties (bayanus and uvarum), which have been raised to the species level by others. In this work, we evaluate the complexity of 46 different strains included in the S. bayanus taxon by means of PCR-RFLP analysis and by sequencing of 34 gene regions and one mitochondrial gene. Using the sequence data, and based on the S. bayanus var. bayanus reference strain NBRC 1948, a hypothetical pure S. bayanus was reconstructed for these genes that showed alleles with similarity values lower than 97% with the S. bayanus var. uvarum strain CBS 7001, and of 99-100% with the non S. cerevisiae portion in S. pastorianus Weihenstephan 34/70 and with the new species S. eubayanus. Among the S. bayanus strains under study, different levels of homozygosity, hybridization and introgression were found; however, no pure S. bayanus var. bayanus strain was identified. These S. bayanus hybrids can be classified into two types: homozygous (type I) and heterozygous hybrids (type II), indicating that they have been originated by different hybridization processes. Therefore, a putative evolutionary scenario involving two different hybridization events between a S. bayanus var. uvarum and unknown European S. eubayanus-like strains can be postulated to explain the genomic diversity observed in our S. bayanus var. bayanus strains. PMID:24705561

  6. Targeted Removal of Ant Colonies in Ecological Experiments, Using Hot Water

    PubMed Central

    Tschinkel, Walter R.; King, Joshua R.

    2007-01-01

    Ecological experiments on fire ants cannot, or should not, use poison baits to eliminate the fire ants because such baits are not specific to fire ants, or even to ants. Hot water is an extremely effective and specific killing agent for fire ant colonies, but producing large amounts of hot water in the field, and making the production apparatus mobile have been problematical. The construction and use of a charcoal-fired kiln made from a 55-gal. oil drum lined with a sand-fireclay mixture is described. An automobile heater fan powered from a 12-v battery provided a draft. Dual bilge pumps pumped water from a large tank through a long coil of copper tubing within the kiln to produce 4 to 5 l. of hot water per min. The hot water was collected in 20 l. buckets and poured into fire ant nests previously opened by piercing with a stick. The entire assembly was transported in and operated from the back of a pickup truck. Five experimental plots containing 32 to 38 colonies of the fire ant, Solenopsis invicta, Buren (Hymenoptera: Formicidae), were treated with hot water over a period of two years. All colonies on the treatment plots were treated twice with hot water early in 2004, reducing their numbers to zero. However new colonies were formed, and mature colonies expanded into the plots. A third treatment was made in the spring of 2005, after which fire ant populations were suppressed for over a year. Whereas the 5 control plots contained a total of 166 mostly large colonies, the 5 treatment plots contained no live colonies at all. Averaged over a two-year period, a 70% reduction in total number of colonies was achieved (P < 0.001) on the treatment plots, and a 93% reduction of large, mature colonies. Over this same time span, the number of colonies in control plots remained stable. The reduction in colony numbers on the treatment plots was reflected in the pitfall trap samples that recorded a 60% reduction in fire ants. PMID:20233079

  7. Problems with the claim of ecotype and taxon status of the wolf in the Great Lakes region

    USGS Publications Warehouse

    Cronin, Matthew A.; Mech, L. David

    2009-01-01

    Koblmuller et al. (2009) analysed molecular genetic data of the wolf in the Great Lakes (GL) region of the USA and concluded that the animal was a unique ecotype of grey wolf and that genetic data supported the population as a discrete wolf taxon. However, some of the literature that the researchers used to support their position actually did not, and additional confusion arises from indefinite use of terminology. Herein, we discuss the problems with designation of a wolf population as a taxon or ecotype without proper definition and assessment of criteria.

  8. Problematic internet use and problematic online gaming are not the same: findings from a large nationally representative adolescent sample.

    PubMed

    Király, Orsolya; Griffiths, Mark D; Urbán, Róbert; Farkas, Judit; Kökönyei, Gyöngyi; Elekes, Zsuzsanna; Tamás, Domokos; Demetrovics, Zsolt

    2014-12-01

    There is an ongoing debate in the literature whether problematic Internet use (PIU) and problematic online gaming (POG) are two distinct conceptual and nosological entities or whether they are the same. The present study contributes to this question by examining the interrelationship and the overlap between PIU and POG in terms of sex, school achievement, time spent using the Internet and/or online gaming, psychological well-being, and preferred online activities. Questionnaires assessing these variables were administered to a nationally representative sample of adolescent gamers (N=2,073; Mage=16.4 years, SD=0.87; 68.4% male). Data showed that Internet use was a common activity among adolescents, while online gaming was engaged in by a considerably smaller group. Similarly, more adolescents met the criteria for PIU than for POG, and a small group of adolescents showed symptoms of both problem behaviors. The most notable difference between the two problem behaviors was in terms of sex. POG was much more strongly associated with being male. Self-esteem had low effect sizes on both behaviors, while depressive symptoms were associated with both PIU and POG, affecting PIU slightly more. In terms of preferred online activities, PIU was positively associated with online gaming, online chatting, and social networking, while POG was only associated with online gaming. Based on our findings, POG appears to be a conceptually different behavior from PIU, and therefore the data support the notion that Internet Addiction Disorder and Internet Gaming Disorder are separate nosological entities. PMID:25415659

  9. Problematic Internet Use and Problematic Online Gaming Are Not the Same: Findings from a Large Nationally Representative Adolescent Sample

    PubMed Central

    Griffiths, Mark D.; Urbán, Róbert; Farkas, Judit; Kökönyei, Gyöngyi; Elekes, Zsuzsanna; Tamás, Domokos; Demetrovics, Zsolt

    2014-01-01

    Abstract There is an ongoing debate in the literature whether problematic Internet use (PIU) and problematic online gaming (POG) are two distinct conceptual and nosological entities or whether they are the same. The present study contributes to this question by examining the interrelationship and the overlap between PIU and POG in terms of sex, school achievement, time spent using the Internet and/or online gaming, psychological well-being, and preferred online activities. Questionnaires assessing these variables were administered to a nationally representative sample of adolescent gamers (N=2,073; Mage=16.4 years, SD=0.87; 68.4% male). Data showed that Internet use was a common activity among adolescents, while online gaming was engaged in by a considerably smaller group. Similarly, more adolescents met the criteria for PIU than for POG, and a small group of adolescents showed symptoms of both problem behaviors. The most notable difference between the two problem behaviors was in terms of sex. POG was much more strongly associated with being male. Self-esteem had low effect sizes on both behaviors, while depressive symptoms were associated with both PIU and POG, affecting PIU slightly more. In terms of preferred online activities, PIU was positively associated with online gaming, online chatting, and social networking, while POG was only associated with online gaming. Based on our findings, POG appears to be a conceptually different behavior from PIU, and therefore the data support the notion that Internet Addiction Disorder and Internet Gaming Disorder are separate nosological entities. PMID:25415659

  10. Team swimming in ant spermatozoa

    PubMed Central

    Pearcy, Morgan; Delescaille, Noémie; Lybaert, Pascale; Aron, Serge

    2014-01-01

    In species where females mate promiscuously, competition between ejaculates from different males to fertilize the ova is an important selective force shaping many aspects of male reproductive traits, such as sperm number, sperm length and sperm–sperm interactions. In eusocial Hymenoptera (bees, wasps and ants), males die shortly after mating and their reproductive success is ultimately limited by the amount of sperm stored in the queen's spermatheca. Multiple mating by queens is expected to impose intense selective pressure on males to optimize the transfer of sperm to the storage organ. Here, we report a remarkable case of cooperation between spermatozoa in the desert ant Cataglyphis savignyi. Males ejaculate bundles of 50–100 spermatozoa. Sperm bundles swim on average 51% faster than solitary sperm cells. Team swimming is expected to increase the amount of sperm stored in the queen spermatheca and, ultimately, enhance male posthumous fitness. PMID:24919705

  11. Revolutionizing Remote Exploration with ANTS

    NASA Astrophysics Data System (ADS)

    Clark, P. E.; Rilee, M. L.; Curtis, S.; Truszkowski, W.

    2002-05-01

    We are developing the Autonomous Nano-Technology Swarm (ANTS) architecture based on an insect colony analogue for the cost-effective, efficient, systematic survey of remote or inaccessible areas with multiple object targets, including planetary surface, marine, airborne, and space environments. The mission context is the exploration in the 2020s of the most compelling remaining targets in the solar system: main belt asteroids. Main belt asteroids harbor important clues to Solar System origins and evolution which are central to NASA's goals in Space Science. Asteroids are smaller than planets, but their number is far greater, and their combined surface area likely dwarfs the Earth's. An asteroid survey will dramatically increase our understanding of the local resources available for the Human Exploration and Development of Space. During the mission composition, shape, gravity, and orbit parameters could be returned to Earth for perhaps several thousand asteroids. A survey of this area will rival the great explorations that encircled this globe, opened up the New World, and laid the groundwork for the progress and challenges of the last centuries. The ANTS architecture for a main belt survey consists of a swarm of as many as a thousand or more highly specialized pico-spacecraft that form teams to survey as many as one hundred asteroids a month. Multi-level autonomy is critical for ANTS and the objective of the proposed study is to work through the implications and constraints this entails. ANTS couples biologically inspired autonomic control for basic functions to higher level artificial intelligence that together enable individual spacecraft to operate as specialized, cooperative, social agents. This revolutionary approach postulates highly advanced, but familiar, components integrated and operated in a way that uniquely transcends any evolutionary extrapolation of existing trends and enables thousand-spacecraft missions.

  12. Interpersonal relationships, coping strategies and problematic internet use in adolescence: an italian study.

    PubMed

    Milani, Luca; Osualdella, Dania; Di Blasio, Paola

    2009-01-01

    In a few years the Internet has become one of the most relevant means of socialization and entertainment for Italian adolescents. Studies have established a correlation between poor interpersonal relationship, poor cognitive coping strategies and Problematic Internet Use. The aim of the research was to study the characteristics and correlates of Problematic Internet Use in an Italian sample of adolescents. 98 Italian adolescents aged 14-19 were administered checklists assessing Problematic Internet Use, quality of interpersonal relationships, and cognitive-driven coping strategies. Of the participants, 36.7% are characterized by Problematic Internet Use. This subsample showed poorer interpersonal relationships and cognitive coping strategies compared to the non-problematic subsample. Overall quality of interpersonal relationships and cognitive coping strategies were found to be predictors of the level of Internet Problematic Use. PMID:19592733

  13. Fire ant-detecting canines: a complementary method in detecting red imported fire ants.

    PubMed

    Lin, Hui-Min; Chi, Wei-Lien; Lin, Chung-Chi; Tseng, Yu-Ching; Chen, Wang-Ting; Kung, Yu-Ling; Lien, Yi-Yang; Chen, Yang-Yuan

    2011-02-01

    In this investigation, detection dogs are trained and used in identifying red imported fire ants, Solenopsis invicta Buren, and their nests. The methodology could assist in reducing the frequency and scope of chemical treatments for red imported fire ant management and thus reduce labor costs and chemical use as well as improve control and quarantine efficiency. Three dogs previously trained for customs quarantine were retrained to detect the scents of red imported fire ants. After passing tests involving different numbers of live red imported fire ants and three other ant species--Crematogaster rogenhoferi Mayr, Paratrechina longicornis Latreille, and Pheidole megacephala F.--placed in containers, ajoint field survey for red imported fire ant nests by detection dogs and bait traps was conducted to demonstrate their use as a supplement to conventional detection methods. The most significant findings in this report are (1) with 10 or more red imported fire ants in scent containers, the dogs had >98% chance in tracing the red imported fire ant. Upon the introduction of other ant species, the dogs still achieved on average, a 93% correct red imported fire ant indication rate. Moreover, the dogs demonstrated great competence in pinpointing emerging and smaller red imported fire ant nests in red imported fire ant-infested areas that had been previously confirmed by bait trap stations. (2) Along with the bait trap method, we also discovered that approximately 90% of red imported fire ants foraged within a distance of 14 m away from their nests. The results prove detection dogs to be most effective for red imported fire ant control in areas that have been previously treated with pesticides and therefore containing a low density of remaining red imported fire ant nests. Furthermore, as a complement to other red imported fire ant monitoring methods, this strategy will significantly increase the efficacy of red imported fire ant control in cases of individual mount treatment

  14. An Early Cambrian problematic fossil: Vetustovermis and its possible affinities

    PubMed Central

    Chen, Jun-yuan; Huang, Di-ying; Bottjer, David J

    2005-01-01

    The Early Cambrian problematic fossil Vetustovermis (Glaessner 1979 Alcheringa 3, 21–31) was described as an annelid or arthropod. Anatomical analysis of 17 new specimens from the Lower Cambrian Maotianshan Shale at Anning, Kunming (South China) does not support its affinities with annelids or arthropods. Anatomical features instead resemble other animal groups including modern flatworms, nemertines and molluscs. The presence of a pelagic slug-like form and ventral foot, as well as a head with eyes and tentacles indicates a possible affinity with molluscs, but these characters are not present only in molluscs; some of them are shared with other animal groups, including flatworms and nemertines. For example, a ventral foot-like structure is found in nemertines, ‘turbellarians’, and some polychaete groups. The well differentiated head is seen in separate bilaterian groups, but among molluscs it did not occur before the evolutionary level of the Conchifera. Unlike the ctenia-gills in molluscs, the gills in Vetustovermis are bar-like. All the characters displayed in this 525 million-year old soft-bodied animal fail to demonstrate clear affinity with molluscs or any other known extant or extinct animal groups, but argue for representing an independently evolved animal group, which flourished in Early Cambrian and possibly in Middle Cambrian time. PMID:16191609

  15. Identifying problematic drugs based on the characteristics of their targets

    PubMed Central

    Lopes, Tiago J. S.; Shoemaker, Jason E.; Matsuoka, Yukiko; Kawaoka, Yoshihiro; Kitano, Hiroaki

    2015-01-01

    Identifying promising compounds during the early stages of drug development is a major challenge for both academia and the pharmaceutical industry. The difficulties are even more pronounced when we consider multi-target pharmacology, where the compounds often target more than one protein, or multiple compounds are used together. Here, we address this problem by using machine learning and network analysis to process sequence and interaction data from human proteins to identify promising compounds. We used this strategy to identify properties that make certain proteins more likely to cause harmful effects when targeted; such proteins usually have domains commonly found throughout the human proteome. Additionally, since currently marketed drugs hit multiple targets simultaneously, we combined the information from individual proteins to devise a score that quantifies the likelihood of a compound being harmful to humans. This approach enabled us to distinguish between approved and problematic drugs with an accuracy of 60–70%. Moreover, our approach can be applied as soon as candidate drugs are available, as demonstrated with predictions for more than 5000 experimental drugs. These resources are available at http://sourceforge.net/projects/psin/. PMID:26388775

  16. Problematic Internet Use Among US Youth: A Systematic Review

    PubMed Central

    Moreno, Megan A; Jelenchick, Lauren; Cox, Elizabeth; Young, Henry; Christakis, Dimitri A

    2011-01-01

    Objectives To investigate study quality and reported prevalence among the emergent area of problematic internet use (PIU) research conducted in populations of US adolescents and college students. Data sources We searched PubMed, PsychInfo and Web of Knowledge from inception to July 2010. Study selection Using a keyword search, we evaluated English-language PIU studies with populations of US adolescents and college students. Main outcome measures Using a quality review tool based on the STROBE statement, two reviewers independently extracted data items including study setting, subject population, instrument used and reported prevalence. Results Search results yielded 658 manuscripts. We identified 18 research studies that met inclusion criteria. Quality assessment of studies ranged between 14 and 29 total points out of a possible 42 points, the average score was 23 (SD 5.1). Among these 18 studies, 8 reported prevalence estimates of US college student PIU, prevalence rates ranged from 0 to 26.3%. An additional 10 studies did not report prevalence. Conclusion The evaluation of PIU remains incomplete and is hampered by methodological inconsistencies. The wide range of conceptual approaches may have impacted the reported prevalence rates. Despite the newness of this area of study, most studies in our review were published over 3 years ago. Opportunities exist to pursue future studies adhering to recognized quality guidelines, as well as applying consistency in theoretical approach and validated instruments. PMID:21536950

  17. Intensive removal of signal crayfish (Pacifastacus leniusculus) from rivers increases numbers and taxon richness of macroinvertebrate species.

    PubMed

    Moorhouse, Tom P; Poole, Alison E; Evans, Laura C; Bradley, David C; Macdonald, David W

    2014-02-01

    Invasive species are a major cause of species extinction in freshwater ecosystems, and crayfish species are particularly pervasive. The invasive American signal crayfish Pacifastacus leniusculus has impacts over a range of trophic levels, but particularly on benthic aquatic macroinvertebrates. Our study examined the effect on the macroinvertebrate community of removal trapping of signal crayfish from UK rivers. Crayfish were intensively trapped and removed from two tributaries of the River Thames to test the hypothesis that lowering signal crayfish densities would result in increases in macroinvertebrate numbers and taxon richness. We removed 6181 crayfish over four sessions, resulting in crayfish densities that decreased toward the center of the removal sections. Conversely in control sections (where crayfish were trapped and returned), crayfish density increased toward the center of the section. Macroinvertebrate numbers and taxon richness were inversely correlated with crayfish densities. Multivariate analysis of the abundance of each taxon yielded similar results and indicated that crayfish removals had positive impacts on macroinvertebrate numbers and taxon richness but did not alter the composition of the wider macroinvertebrate community. Synthesis and applications: Our results demonstrate that non-eradication-oriented crayfish removal programmes may lead to increases in the total number of macroinvertebrates living in the benthos. This represents the first evidence that removing signal crayfish from riparian systems, at intensities feasible during control attempts or commercial crayfishing, may be beneficial for a range of sympatric aquatic macroinvertebrates. PMID:24634733

  18. Intensive removal of signal crayfish (Pacifastacus leniusculus) from rivers increases numbers and taxon richness of macroinvertebrate species

    PubMed Central

    Moorhouse, Tom P; Poole, Alison E; Evans, Laura C; Bradley, David C; Macdonald, David W

    2014-01-01

    Invasive species are a major cause of species extinction in freshwater ecosystems, and crayfish species are particularly pervasive. The invasive American signal crayfish Pacifastacus leniusculus has impacts over a range of trophic levels, but particularly on benthic aquatic macroinvertebrates. Our study examined the effect on the macroinvertebrate community of removal trapping of signal crayfish from UK rivers. Crayfish were intensively trapped and removed from two tributaries of the River Thames to test the hypothesis that lowering signal crayfish densities would result in increases in macroinvertebrate numbers and taxon richness. We removed 6181 crayfish over four sessions, resulting in crayfish densities that decreased toward the center of the removal sections. Conversely in control sections (where crayfish were trapped and returned), crayfish density increased toward the center of the section. Macroinvertebrate numbers and taxon richness were inversely correlated with crayfish densities. Multivariate analysis of the abundance of each taxon yielded similar results and indicated that crayfish removals had positive impacts on macroinvertebrate numbers and taxon richness but did not alter the composition of the wider macroinvertebrate community. Synthesis and applications: Our results demonstrate that non-eradication-oriented crayfish removal programmes may lead to increases in the total number of macroinvertebrates living in the benthos. This represents the first evidence that removing signal crayfish from riparian systems, at intensities feasible during control attempts or commercial crayfishing, may be beneficial for a range of sympatric aquatic macroinvertebrates. PMID:24634733

  19. The Genome Sequence of Bifidobacterium moukalabense DSM 27321 Highlights the Close Phylogenetic Relatedness with the Bifidobacterium dentium Taxon.

    PubMed

    Lugli, Gabriele Andrea; Duranti, Sabrina; Milani, Christian; Turroni, Francesca; Viappiani, Alice; Mangifesta, Marta; van Sinderen, Douwe; Ventura, Marco

    2014-01-01

    Bifidobacterium moukalabense DSM 27321 is the reference strain for a recently described new bifidobacterial species that has been isolated from a wild west lowland gorilla. Here, we report the whole-genome sequence of DSM 27321, which supports very close phylogenetic relatedness with members of the Bifidobacterium adolescentis phylogenetic group and, in particular, the Bifidobacterium dentium taxon. PMID:24558236

  20. Usefulness of fire ant genetics in insecticide efficacy trials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mature fire ant colonies contain an average of 80,000 worker ants. For this study, eight fire ant workers were randomly sampled from each colony. DNA fingerprints for each individual ant were generated using 21 simple sequence repeats (SSR) markers that were developed from fire ant DNA by other lab...

  1. Blind and myopic ants in heterogeneous networks

    NASA Astrophysics Data System (ADS)

    Hwang, S.; Lee, D.-S.; Kahng, B.

    2014-11-01

    The diffusion processes on complex networks may be described by different Laplacian matrices due to heterogeneous connectivity. Here we investigate the random walks of blind ants and myopic ants on heterogeneous networks: While a myopic ant hops to a neighbor node every step, a blind ant may stay or hop with probabilities that depend on node connectivity. By analyzing the trajectories of blind ants, we show that the asymptotic behaviors of both random walks are related by rescaling time and probability with node connectivity. Using this result, we show how the small eigenvalues of the Laplacian matrices generating the two random walks are related. As an application, we show how the return-to-origin probability of a myopic ant can be used to compute the scaling behaviors of the Edwards-Wilkinson model, a representative model of load balancing on networks.

  2. Blind and myopic ants in heterogeneous networks.

    PubMed

    Hwang, S; Lee, D-S; Kahng, B

    2014-11-01

    The diffusion processes on complex networks may be described by different Laplacian matrices due to heterogeneous connectivity. Here we investigate the random walks of blind ants and myopic ants on heterogeneous networks: While a myopic ant hops to a neighbor node every step, a blind ant may stay or hop with probabilities that depend on node connectivity. By analyzing the trajectories of blind ants, we show that the asymptotic behaviors of both random walks are related by rescaling time and probability with node connectivity. Using this result, we show how the small eigenvalues of the Laplacian matrices generating the two random walks are related. As an application, we show how the return-to-origin probability of a myopic ant can be used to compute the scaling behaviors of the Edwards-Wilkinson model, a representative model of load balancing on networks. PMID:25493841

  3. Symbiont recruitment versus ant-symbiont co-evolution in the attine ant-microbe symbiosis.

    PubMed

    Mueller, Ulrich G

    2012-06-01

    The symbiosis between fungus-farming ants (Attini, Formicidae), their cultivated fungi, garden-infecting Escovopsis pathogens, and Pseudonocardia bacteria on the ant integument has been popularized as an example of ant-Escovopsis-Pseudonocardia co-evolution. Recent research could not verify earlier conclusions regarding antibiotic-secreting, integumental Pseudonocardia that co-evolve to specifically suppress Escovopsis disease in an ancient co-evolutionary arms-race. Rather than long-term association with a single, co-evolving Pseudonocardia strain, attine ants accumulate complex, dynamic biofilms on their integument and in their gardens. Emerging views are that the integumental biofilms protect the ants primarily against ant diseases, whereas garden biofilms protect primarily against garden diseases; attine ants selectively recruit ('screen in') microbes into their biofilms; and the biofilms of ants and gardens serve diverse functions beyond disease-suppression. PMID:22445196

  4. An Efficient Ant-Based Edge Detector

    NASA Astrophysics Data System (ADS)

    Aydın, Doğan

    An efficient ant-based edge detector is presented. It is based on the distribution of ants on an image, ants try to find possible edges by using a state transition function based on 5x5 edge structures. Visual comparisons show that the proposed method gives finer details and thinner edges at lesser computational times when compared to earlier ant-based approaches. When compared to standard edge detectors, it shows robustness to Gaussian and Salt & Pepper noise and provides finer details than others with same parameter set in both clear and noisy images.

  5. Major evolutionary transitions in ant agriculture

    PubMed Central

    Schultz, Ted R.; Brady, Seán G.

    2008-01-01

    Agriculture is a specialized form of symbiosis that is known to have evolved in only four animal groups: humans, bark beetles, termites, and ants. Here, we reconstruct the major evolutionary transitions that produced the five distinct agricultural systems of the fungus-growing ants, the most well studied of the nonhuman agriculturalists. We do so with reference to the first fossil-calibrated, multiple-gene, molecular phylogeny that incorporates the full range of taxonomic diversity within the fungus-growing ant tribe Attini. Our analyses indicate that the original form of ant agriculture, the cultivation of a diverse subset of fungal species in the tribe Leucocoprineae, evolved ≈50 million years ago in the Neotropics, coincident with the early Eocene climatic optimum. During the past 30 million years, three known ant agricultural systems, each involving a phylogenetically distinct set of derived fungal cultivars, have separately arisen from the original agricultural system. One of these derived systems subsequently gave rise to the fifth known system of agriculture, in which a single fungal species is cultivated by leaf-cutter ants. Leaf-cutter ants evolved remarkably recently (≈8–12 million years ago) to become the dominant herbivores of the New World tropics. Our analyses identify relict, extant attine ant species that occupy phylogenetic positions that are transitional between the agricultural systems. Intensive study of those species holds particular promise for clarifying the sequential accretion of ecological and behavioral characters that produced each of the major ant agricultural systems. PMID:18362345

  6. Plants in Your Ants: Using Ant Mounds to Test Basic Ecological Principles

    ERIC Educational Resources Information Center

    Zettler, Jennifer A.; Collier, Alexander; Leidersdorf, Bil; Sanou, Missa Patrick

    2010-01-01

    Urban students often have limited access to field sites for ecological studies. Ubiquitous ants and their mounds can be used to study and test ecology-based questions. We describe how soil collected from ant mounds can be used to investigate how biotic factors (ants) can affect abiotic factors in the soil that can, in turn, influence plant growth.

  7. Problematic Exercise in Anorexia Nervosa: Testing Potential Risk Factors against Different Definitions.

    PubMed

    Rizk, Melissa; Lalanne, Christophe; Berthoz, Sylvie; Kern, Laurence; Godart, Nathalie

    2015-01-01

    "Hyperactivity" has a wide prevalence range of 31% to 80% in the anorexia nervosa literature that could be partly due to the plethora of definitions provided by researchers in this field. The purpose of this study was two-fold: 1) To assess the variance across prevalence rates of problematic exercise encountered in patients with anorexia nervosa, in relation to seven different definitions found in the literature. 2) To examine how core eating disorder symptoms and the dimensions of emotional profile are associated with these different definitions and the impact of these definitions on the assessment of patients' quality of life. Exercise was evaluated in terms of duration, intensity, type and compulsion using a semi-structured questionnaire administered to 180 women suffering from severe anorexia nervosa. Seven different definitions of problematic exercise were identified in the literature: three entailing a single dimension of problematic exercise (duration, compulsion or intensity) and four combining these different dimensions. Emotional profile scores, obsessive-compulsive symptoms, eating disorder symptomatology, worries and concerns about body shape, self-esteem and quality of life were assessed using several established questionnaires. The prevalence of problematic exercise varied considerably from, 5% to 54%, depending on the number of criteria used for its definition. The type and level of eating disorder symptomatology was found to be associated with several definitions of problematic exercise. Surprisingly, a better self-reported quality of life was found among problematic exercisers compared to non-problematic exercisers in three of the definitions. The different definitions of problematic exercise explain the broad prevalence ranges and the conflicting associations generally reported in the literature between problematic exercise and eating disorder-related psychological parameters. There is an urgent need for a valid consensus on the definition of

  8. Problematic Exercise in Anorexia Nervosa: Testing Potential Risk Factors against Different Definitions

    PubMed Central

    Rizk, Melissa; Lalanne, Christophe; Berthoz, Sylvie; Kern, Laurence; Godart, Nathalie

    2015-01-01

    “Hyperactivity” has a wide prevalence range of 31% to 80% in the anorexia nervosa literature that could be partly due to the plethora of definitions provided by researchers in this field. The purpose of this study was two-fold: 1) To assess the variance across prevalence rates of problematic exercise encountered in patients with anorexia nervosa, in relation to seven different definitions found in the literature. 2) To examine how core eating disorder symptoms and the dimensions of emotional profile are associated with these different definitions and the impact of these definitions on the assessment of patients’ quality of life. Exercise was evaluated in terms of duration, intensity, type and compulsion using a semi-structured questionnaire administered to 180 women suffering from severe anorexia nervosa. Seven different definitions of problematic exercise were identified in the literature: three entailing a single dimension of problematic exercise (duration, compulsion or intensity) and four combining these different dimensions. Emotional profile scores, obsessive-compulsive symptoms, eating disorder symptomatology, worries and concerns about body shape, self-esteem and quality of life were assessed using several established questionnaires. The prevalence of problematic exercise varied considerably from, 5% to 54%, depending on the number of criteria used for its definition. The type and level of eating disorder symptomatology was found to be associated with several definitions of problematic exercise. Surprisingly, a better self-reported quality of life was found among problematic exercisers compared to non-problematic exercisers in three of the definitions. The different definitions of problematic exercise explain the broad prevalence ranges and the conflicting associations generally reported in the literature between problematic exercise and eating disorder-related psychological parameters. There is an urgent need for a valid consensus on the definition

  9. Complications of systemic corticosteroid therapy for problematic hemangioma.

    PubMed

    Boon, L M; MacDonald, D M; Mulliken, J B

    1999-11-01

    Systemic corticosteroid therapy has been used to treat hemangiomas for 30 years; yet, there are no studies of possible complications. We reviewed the database of the Vascular Anomalies Center at the Boston Children's Hospital and gathered information on short- and long-term side effects in children who were given systemic corticosteroids for problematic hemangiomas. In addition, a questionnaire regarding early and late consequences was sent to the families of children who were treated with corticosteroids from 1983 to 1997. Of 300 patients with hemangiomas, 80 children were identified as having received a full course of systemic corticosteroids for problematic tumors. Complete data were collected on 62 of these children. The response rate to the questionnaire was 78 percent (n = 62 of 80). The initial dose of corticosteroid varied from 2 to 3 mg/kg/ day. Duration of therapy ranged from 2 to 21 months (mean, 7.9 months; median, 6.5 months). The follow-up interval from the cessation of therapy ranged from 6 months to 15 years (mean, 4 years; median, 3 years). Short-term complications included cushingoid facies (n = 44; 71 percent), personality changes (n = 18; 29 percent), gastric irritation (n = 13; 21 percent), fungal (oral or perineal) infection (n = 4; 6 percent), and diminished gain of height (n = 22; 35 percent) and weight (n = 26; 42 percent). A total of 91 percent of children who had diminished gain of height (n = 20) returned to their pretreatment growth curve for height by 24 months of age. One child, who was treated at another institution with a dose of 20 mg/kg/day for 6.5 months that was slowly tapered over 18 months, was petite 6 years after ending therapy. Another child treated with an initial dose of 2 mg/kg/day for 5 months was smaller than predicted at the age of 6 years, but she was born prematurely and was on ventilatory support for respiratory distress. Three children treated with the standard dose and duration were at a low percentile for weight

  10. Taxon-specific PCR for DNA barcoding arthropod prey in bat faeces.

    PubMed

    Zeale, Matt R K; Butlin, Roger K; Barker, Gary L A; Lees, David C; Jones, Gareth

    2011-03-01

    The application of DNA barcoding to dietary studies allows prey taxa to be identified in the absence of morphological evidence and permits a greater resolution of prey identity than is possible through direct examination of faecal material. For insectivorous bats, which typically eat a great diversity of prey and which chew and digest their prey thoroughly, DNA-based approaches to diet analysis may provide the only means of assessing the range and diversity of prey within faeces. Here, we investigated the effectiveness of DNA barcoding in determining the diets of bat species that specialize in eating different taxa of arthropod prey. We designed and tested a novel taxon-specific primer set and examined the performance of short barcode sequences in resolving prey species. We recovered prey DNA from all faecal samples and subsequent cloning and sequencing of PCR products, followed by a comparison of sequences to a reference database, provided species-level identifications for 149/207 (72%) clones. We detected a phylogenetically broad range of prey while completely avoiding detection of nontarget groups. In total, 37 unique prey taxa were identified from 15 faecal samples. A comparison of DNA data with parallel morphological analyses revealed a close correlation between the two methods. However, the sensitivity and taxonomic resolution of the DNA method were far superior. The methodology developed here provides new opportunities for the study of bat diets and will be of great benefit to the conservation of these ecologically important predators. PMID:21429129

  11. Single-taxon field measurements of bacterial gene regulation controlling DMSP fate

    PubMed Central

    Varaljay, Vanessa A; Robidart, Julie; Preston, Christina M; Gifford, Scott M; Durham, Bryndan P; Burns, Andrew S; Ryan, John P; Marin III, Roman; Kiene, Ronald P; Zehr, Jonathan P; Scholin, Christopher A; Ann Moran, Mary

    2015-01-01

    The ‘bacterial switch' is a proposed regulatory point in the global sulfur cycle that routes dimethylsulfoniopropionate (DMSP) to two fundamentally different fates in seawater through genes encoding either the cleavage or demethylation pathway, and affects the flux of volatile sulfur from ocean surface waters to the atmosphere. Yet which ecological or physiological factors might control the bacterial switch remains a topic of considerable debate. Here we report the first field observations of dynamic changes in expression of DMSP pathway genes by a single marine bacterial species in its natural environment. Detection of taxon-specific gene expression in Roseobacter species HTCC2255 during a month-long deployment of an autonomous ocean sensor in Monterey Bay, CA captured in situ regulation of the first gene in each DMSP pathway (dddP and dmdA) that corresponded with shifts in the taxonomy of the phytoplankton community. Expression of the cleavage pathway was relatively greater during a high-DMSP-producing dinoflagellate bloom, and expression of the demethylation pathway was greater in the presence of a mixed diatom and dinoflagellate community. These field data fit the prevailing hypothesis for bacterial DMSP gene regulation based on bacterial sulfur demand, but also suggest a modification involving oxidative stress response, evidenced as upregulation of catalase via katG, when DMSP is demethylated. PMID:25700338

  12. Single-taxon field measurements of bacterial gene regulation controlling DMSP fate.

    PubMed

    Varaljay, Vanessa A; Robidart, Julie; Preston, Christina M; Gifford, Scott M; Durham, Bryndan P; Burns, Andrew S; Ryan, John P; Marin, Roman; Kiene, Ronald P; Zehr, Jonathan P; Scholin, Christopher A; Moran, Mary Ann

    2015-07-01

    The 'bacterial switch' is a proposed regulatory point in the global sulfur cycle that routes dimethylsulfoniopropionate (DMSP) to two fundamentally different fates in seawater through genes encoding either the cleavage or demethylation pathway, and affects the flux of volatile sulfur from ocean surface waters to the atmosphere. Yet which ecological or physiological factors might control the bacterial switch remains a topic of considerable debate. Here we report the first field observations of dynamic changes in expression of DMSP pathway genes by a single marine bacterial species in its natural environment. Detection of taxon-specific gene expression in Roseobacter species HTCC2255 during a month-long deployment of an autonomous ocean sensor in Monterey Bay, CA captured in situ regulation of the first gene in each DMSP pathway (dddP and dmdA) that corresponded with shifts in the taxonomy of the phytoplankton community. Expression of the demethylation pathway was relatively greater during a high-DMSP-producing dinoflagellate bloom, and expression of the cleavage pathway was greater in the presence of a mixed diatom and dinoflagellate community [corrected].These field data fit the prevailing hypothesis for bacterial DMSP gene regulation based on bacterial sulfur demand, but also suggest a modification involving oxidative stress response, evidenced as upregulation of catalase via katG, when DMSP is demethylated. PMID:25700338

  13. Negevirus: a proposed new taxon of insect-specific viruses with wide geographic distribution.

    PubMed

    Vasilakis, Nikos; Forrester, Naomi L; Palacios, Gustavo; Nasar, Farooq; Savji, Nazir; Rossi, Shannan L; Guzman, Hilda; Wood, Thomas G; Popov, Vsevolod; Gorchakov, Rodion; González, Ana Vázquez; Haddow, Andrew D; Watts, Douglas M; da Rosa, Amelia P A Travassos; Weaver, Scott C; Lipkin, W Ian; Tesh, Robert B

    2013-03-01

    Six novel insect-specific viruses, isolated from mosquitoes and phlebotomine sand flies collected in Brazil, Peru, the United States, Ivory Coast, Israel, and Indonesia, are described. Their genomes consist of single-stranded, positive-sense RNAs with poly(A) tails. By electron microscopy, the virions appear as spherical particles with diameters of ∼45 to 55 nm. Based on their genome organization and phylogenetic relationship, the six viruses, designated Negev, Ngewotan, Piura, Loreto, Dezidougou, and Santana, appear to form a new taxon, tentatively designated Negevirus. Their closest but still distant relatives are citrus leposis virus C (CiLV-C) and viruses in the genus Cilevirus, which are mite-transmitted plant viruses. The negeviruses replicate rapidly and to high titer (up to 10(10) PFU/ml) in mosquito cells, producing extensive cytopathic effect and plaques, but they do not appear to replicate in mammalian cells or mice. A discussion follows on their possible biological significance and effect on mosquito vector competence for arboviruses. PMID:23255793

  14. Biological richness of a large urban cemetery in Berlin. Results of a multi-taxon approach

    PubMed Central

    Blick, Theo; Hannig, Karsten; Kowarik, Ingo; Lemke, Andreas; Otte, Volker; Scharon, Jens; Schönhofer, Axel; Teige, Tobias; von der Lippe, Moritz; Seitz, Birgit

    2016-01-01

    Abstract Background Urban green spaces can harbor a considerable species richness of plants and animals. A few studies on single species groups indicate important habitat functions of cemeteries, but this land use type is clearly understudied compared to parks. Such data are important as they (i) illustrate habitat functions of a specific, but ubiquitous urban land-use type and (ii) may serve as a basis for management approaches. New information We sampled different groups of plants and animals in the Weißensee Jewish Cemetery in Berlin (WJC) which is one of the largest Jewish cemeteries in Europe. With a total of 608 species of plants and animals, this first multi-taxon survey revealed a considerable biological richness in the WJC. In all, 363 wild-growing vascular plant, 72 lichen and 26 bryophyte taxa were recorded. The sampling also yielded 34 bird and 5 bat species as well as 39 ground beetle, 5 harvestman and 64 spider species. Some species are new records for Berlin. PMID:27099549

  15. A New Taxon of Basal Ceratopsian from China and the Early Evolution of Ceratopsia

    PubMed Central

    Han, Fenglu; Forster, Catherine A.; Clark, James M.; Xu, Xing

    2015-01-01

    Ceratopsia is one of the best studied herbivorous ornithischian clades, but the early evolution of Ceratopsia, including the placement of Psittacosaurus, is still controversial and unclear. Here, we report a second basal ceratopsian, Hualianceratops wucaiwanensis gen. et sp. nov., from the Upper Jurassic (Oxfordian) Shishugou Formation of the Junggar Basin, northwestern China. This new taxon is characterized by a prominent caudodorsal process on the subtemporal ramus of the jugal, a robust quadrate with an expansive quadratojugal facet, a prominent notch near the ventral region of the quadrate, a deep and short dentary, and strongly rugose texturing on the lateral surface of the dentary. Hualianceratops shares several derived characters with both Psittacosaurus and the basal ceratopsians Yinlong, Chaoyangsaurus, and Xuanhuaceratops. A new comprehensive phylogeny of ceratopsians weakly supports both Yinlong and Hualianceratops as chaoyangsaurids (along with Chaoyangsaurus and Xuanhuaceratops), as well as the monophyly of Chaoyangosauridae + Psittacosaurus. This analysis also weakly supports the novel hypothesis that Chaoyangsauridae + Psittacosaurus is the sister group to the rest of Neoceratopsia, suggesting a basal split between these clades before the Late Jurassic. This phylogeny and the earliest Late Jurassic age of Yinlong and Hualianceratops imply that at least five ceratopsian lineages (Yinlong, Hualianceratops, Chaoyangsaurus + Xuanhuaceratops, Psittacosaurus, Neoceratopsia) were present at the beginning of the Late Jurassic. PMID:26649770

  16. A New Taxon of Basal Ceratopsian from China and the Early Evolution of Ceratopsia.

    PubMed

    Han, Fenglu; Forster, Catherine A; Clark, James M; Xu, Xing

    2015-01-01

    Ceratopsia is one of the best studied herbivorous ornithischian clades, but the early evolution of Ceratopsia, including the placement of Psittacosaurus, is still controversial and unclear. Here, we report a second basal ceratopsian, Hualianceratops wucaiwanensis gen. et sp. nov., from the Upper Jurassic (Oxfordian) Shishugou Formation of the Junggar Basin, northwestern China. This new taxon is characterized by a prominent caudodorsal process on the subtemporal ramus of the jugal, a robust quadrate with an expansive quadratojugal facet, a prominent notch near the ventral region of the quadrate, a deep and short dentary, and strongly rugose texturing on the lateral surface of the dentary. Hualianceratops shares several derived characters with both Psittacosaurus and the basal ceratopsians Yinlong, Chaoyangsaurus, and Xuanhuaceratops. A new comprehensive phylogeny of ceratopsians weakly supports both Yinlong and Hualianceratops as chaoyangsaurids (along with Chaoyangsaurus and Xuanhuaceratops), as well as the monophyly of Chaoyangosauridae + Psittacosaurus. This analysis also weakly supports the novel hypothesis that Chaoyangsauridae + Psittacosaurus is the sister group to the rest of Neoceratopsia, suggesting a basal split between these clades before the Late Jurassic. This phylogeny and the earliest Late Jurassic age of Yinlong and Hualianceratops imply that at least five ceratopsian lineages (Yinlong, Hualianceratops, Chaoyangsaurus + Xuanhuaceratops, Psittacosaurus, Neoceratopsia) were present at the beginning of the Late Jurassic. PMID:26649770

  17. Negevirus: a Proposed New Taxon of Insect-Specific Viruses with Wide Geographic Distribution

    PubMed Central

    Vasilakis, Nikos; Forrester, Naomi L.; Palacios, Gustavo; Nasar, Farooq; Savji, Nazir; Rossi, Shannan L.; Guzman, Hilda; Wood, Thomas G.; Popov, Vsevolod; Gorchakov, Rodion; González, Ana Vázquez; Haddow, Andrew D.; Watts, Douglas M.; da Rosa, Amelia P. A. Travassos; Weaver, Scott C.; Lipkin, W. Ian

    2013-01-01

    Six novel insect-specific viruses, isolated from mosquitoes and phlebotomine sand flies collected in Brazil, Peru, the United States, Ivory Coast, Israel, and Indonesia, are described. Their genomes consist of single-stranded, positive-sense RNAs with poly(A) tails. By electron microscopy, the virions appear as spherical particles with diameters of ∼45 to 55 nm. Based on their genome organization and phylogenetic relationship, the six viruses, designated Negev, Ngewotan, Piura, Loreto, Dezidougou, and Santana, appear to form a new taxon, tentatively designated Negevirus. Their closest but still distant relatives are citrus leposis virus C (CiLV-C) and viruses in the genus Cilevirus, which are mite-transmitted plant viruses. The negeviruses replicate rapidly and to high titer (up to 1010 PFU/ml) in mosquito cells, producing extensive cytopathic effect and plaques, but they do not appear to replicate in mammalian cells or mice. A discussion follows on their possible biological significance and effect on mosquito vector competence for arboviruses. PMID:23255793

  18. Problematic game play: the diagnostic value of playing motives, passion, and playing time in men.

    PubMed

    Kneer, Julia; Rieger, Diana

    2015-01-01

    Internet gaming disorder is currently listed in the DSM-not in order to diagnose such a disorder but to encourage research to investigate this phenomenon. Even whether it is still questionable if Internet Gaming Disorder exists and can be judged as a form of addiction, problematic game play is already very well researched to cause problems in daily life. Approaches trying to predict problematic tendencies in digital game play have mainly focused on playing time as a diagnostic criterion. However, motives to engage in digital game play and obsessive passion for game play have also been found to predict problematic game play but have not yet been investigated together. The present study aims at (1) analyzing if obsessive passion can be distinguished from problematic game play as separate concepts, and (2) testing motives of game play, passion, and playing time for their predictive values for problematic tendencies. We found (N = 99 males, Age: M = 22.80, SD = 3.81) that obsessive passion can be conceptually separated from problematic game play. In addition, the results suggest that compared to solely playing time immersion as playing motive and obsessive passion have added predictive value for problematic game play. The implications focus on broadening the criteria in order to diagnose problematic playing. PMID:25942516

  19. A Comparative Study of Problematic Internet Use and Loneliness among Turkish and Korean Prospective Teachers

    ERIC Educational Resources Information Center

    Tutgun, Aylin; Deniz, Levent; Moon, Man-Ki

    2011-01-01

    The main aim of this study is to compare the problematic internet use and its relation to loneliness among two nations' prospective teachers, Turkey and South Korea. Five hundred and ninety five prospective teachers from three universities, two from Turkey and one from South Korea participated in the study. Generalized Problematic Internet Use…

  20. Problematic Game Play: The Diagnostic Value of Playing Motives, Passion, and Playing Time in Men

    PubMed Central

    Kneer, Julia; Rieger, Diana

    2015-01-01

    Internet gaming disorder is currently listed in the DSM—not in order to diagnose such a disorder but to encourage research to investigate this phenomenon. Even whether it is still questionable if Internet Gaming Disorder exists and can be judged as a form of addiction, problematic game play is already very well researched to cause problems in daily life. Approaches trying to predict problematic tendencies in digital game play have mainly focused on playing time as a diagnostic criterion. However, motives to engage in digital game play and obsessive passion for game play have also been found to predict problematic game play but have not yet been investigated together. The present study aims at (1) analyzing if obsessive passion can be distinguished from problematic game play as separate concepts, and (2) testing motives of game play, passion, and playing time for their predictive values for problematic tendencies. We found (N = 99 males, Age: M = 22.80, SD = 3.81) that obsessive passion can be conceptually separated from problematic game play. In addition, the results suggest that compared to solely playing time immersion as playing motive and obsessive passion have added predictive value for problematic game play. The implications focus on broadening the criteria in order to diagnose problematic playing. PMID:25942516

  1. Teachers' Views on Risk Factors for Problematic School Absenteeism in Swedish Primary School Students

    ERIC Educational Resources Information Center

    Gren-Landell, Malin; Ekerfelt Allvin, Cornelia; Bradley, Maria; Andersson, Maria; Andersson, Gerhard

    2015-01-01

    In the present online survey, 158 teachers in regular and special education teaching in grades six to nine were asked to rate the importance of probable reasons for problematic school absenteeism. On average, the teachers estimated that among their students, 19 students had presented with problematic school absenteeism over the last five years.…

  2. An Investigation of Problematic Internet Usage Behaviors on Turkish University Students

    ERIC Educational Resources Information Center

    Ceyhan, Esra; Ceyhan, A. Aykut

    2007-01-01

    This research aims at examining the relationships between problematic internet usage (PIU) behavior and some demographic information and qualifications related to internet use of Turkish university students. The research was conducted with 2084 university students. Data was collected by means of Problematic Internet Usage Scale (Ceyhan, Ceyhan &…

  3. Exploration of Problematic Internet Use and Social Interaction Anxiety among Turkish Pre-Service Teachers

    ERIC Educational Resources Information Center

    Cuhadar, Cem

    2012-01-01

    The current study investigated the relationship between problematic Internet use and social interaction anxiety among pre-service teachers. Participants were 1235 students attending teacher training programs at a Turkish state university. The "Problematic Internet Use Scale" and "Social Interaction Anxiety Scale" were used to collect the data.…

  4. Exploration of Problematic Internet Use and Loneliness among Distance Education Students

    ERIC Educational Resources Information Center

    Ozgur, Hasan; Demiralay, Tülay; Demiralay, Ilkay

    2014-01-01

    The current study investigated the relationship between problematic Internet use and levels of loneliness among 311 distance education students. "The Problematic Internet Use Scale" and "UCLA-Loneliness Scale III" were used to collect the data. Independentsamples t-test and one-way ANOVA were conducted to examine the…

  5. Problematic use of social network sites: the interactive relationship between gratifications sought and privacy concerns.

    PubMed

    Chen, Hsuan-Ting; Kim, Yonghwan

    2013-11-01

    Problematic Internet use has long been a matter of concern; however, few studies extend this line of research from general Internet use to the use of social network sites (SNSs), or explicate the problematic use of SNSs by understanding what factors may enhance or reduce users' compulsive behaviors and excessive form of use on SNSs. Building on literature that found a positive relationship between gratifications sought from the Internet and problematic Internet use, this study first explores the types of gratifications sought from SNSs and examines their relationship with problematic SNS use. It found that three types of gratifications-diversion, self-presentation, and relationship building-were positively related to problematic SNS use. In addition, with a growing body of research on SNS privacy, a moderating role of privacy concerns on SNSs has been proposed to understand how it can influence the relationship between gratifications sought from SNSs and problematic SNS use. The findings suggest that different subdimensions of privacy concerns interact with gratifications sought in different manners. In other words, privacy concerns, including unauthorized secondary use and improper access, play a more influential role in constraining the positive relationship between gratifications sought and problematic SNS use when individuals seek to build relationships on SNSs. However, if individuals seek to have diversion on SNSs, their privacy concerns will be overridden by their gratifications sought, which in turn leads to problematic SNS use. Implications of these findings for future research are discussed. PMID:24053383

  6. A preliminary investigation into the prevalence and prediction of problematic cell phone use

    PubMed Central

    Smetaniuk, Peter

    2014-01-01

    Background and aims: Likening mobile phone use dependency to the classification of excessive behaviors may be necessarily equivalent in seriousness to previously established addictions such as problematic computing or excessive gambling. The aim of the study explores into the behavior of excessive use of mobile phones as a pathological behavior. Methods: Two studies investigated criteria for problematic mobile phone usage by examining student (Study 1, N = 301) and nonstudent (Study 2, N = 362) responses to a set of adapted mobile phone addiction inventories. Study 1 investigated cell phone addiction inventories as constructs designed to measure problematic cell phone use. Additionally, Study 2 sought to predict age, depression, extraversion, emotional stability, impulse control, and self-esteem as independent variables that augment respondents’ perceptions of problematic use. Results: The results from Study 1 and Study 2 indicate that 10 to 25% of the participants tested exhibited problematic cell phone usage. Additionally, age, depression, extraversion, and low impulse control are the most suitable predictors for problematic use. Conclusions: The results of the two studies indicate that problematic mobile phone use does occur and ought to be taken seriously by the psychological community. Presently, there is limited data providing conclusive evidence for a comprehensible categorization of cell phone addiction, as well as a unified explanatory model specific to problematic mobile phone use. Studies such as this one may contribute substantial findings, adding scientific significance, and offering a valuable submission for the ongoing progress of creating intervention frameworks relative to “virtual addictions”. PMID:25215213

  7. Problematic Student in the Experiential Group: Professional and Ethical Challenges for Counselor Educators

    ERIC Educational Resources Information Center

    Goodrich, Kristopher M.; Luke, Melissa

    2012-01-01

    This article updates and adds to the literature about problematic counselors-in-training, specifically centered on the requisite experiential group component in the Association for Specialists in Group Work Professional Training Standards (2000) and CACREP (2009) curriculum. The authors review the literature regarding problematic behavior, present…

  8. ANT2-defective fibroblasts exhibit normal mitochondrial bioenergetics

    PubMed Central

    Prabhu, Dolly; Goldstein, Amy C.; El-Khoury, Riyad; Rak, Malgorzata; Edmunds, Lia; Rustin, Pierre; Vockley, Jerry; Schiff, Manuel

    2015-01-01

    Adenine nucleotide translocase 2 (ANT2) transports glycolytic ATP across the inner mitochondrial membrane. Patients with ANT2 deletion were recently reported. We aimed at characterizing mitochondrial functions in ANT2-defective fibroblasts. In spite of ANT2 expression in fibroblasts, we observed no difference between ANT2-defective and control fibroblasts for mitochondrial respiration, respiratory chain activities, mitochondrial membrane potential and intracellular ATP levels. This indicates that ANT2 insufficiency does not alter fibroblast basal mitochondrial bioenergetics. PMID:26000237

  9. The impact of shyness on problematic internet use: the role of loneliness.

    PubMed

    Huan, Vivien S; Ang, Rebecca P; Chong, Wan Har; Chye, Stefanie

    2014-01-01

    In recent years, research indicated that the problematic effects of Internet use must be examined together with individual differences present in its users with which such effects are contingent. This study examined loneliness in adolescents as a mediator of the relationship between shyness and their generalized problematic Internet use (PIU). A total of 1469 adolescents (48.5% male, 51.5% female) from Grade 8 and Grade 9 classes participated in this study. Using the Social Reticence Scale (SRS), the revised UCLA Loneliness scale and the Generalized Problematic Internet Use scale, initial findings indicated significant correlations among the three variables. Results from the study further revealed that loneliness completely mediated the relationship between shyness and generalized problematic Internet use. Implications for intervention work addressing both loneliness and shyness issues facing adolescents who are problematic users of the Internet were discussed. PMID:25175891

  10. Risk factors and psychosocial characteristics of potential problematic and problematic internet use among adolescents: A cross-sectional study

    PubMed Central

    2011-01-01

    Background Problematic internet use (PIU) is associated with a plethora of psychosocial adversities. The study objectives were to assess the determinants and psychosocial implications associated with potential PIU and PIU among adolescents. Methods A cross-sectional study design was applied among a random sample (n = 866) of Greek adolescents (mean age: 14.7 years). Self-completed questionnaires, including internet use characteristics, Young Internet Addiction Test, and Strengths and Difficulties Questionnaire, were utilized to examine the study objectives. Results Among the study population, the prevalence rates of potential PIU and PIU were 19.4% and 1.5%, respectively. Multinomial logistic regression indicated that male gender (Odds Ratio, OR: 2.01; 95% Confidence Interval, 95% CI: 1.35-3.00), as well as utilizing the internet for retrieving sexual information (OR: 2.52; 95% CI: 1.53-4.12), interactive game playing (OR: 1.85; 95% CI: 1.21-2.82), and socialization, including chat-room use (OR: 1.97; 95% CI: 1.36-2.86) and email (OR: 1.53; 95% CI: 1.05-2.24), were independently associated with potential PIU and PIU. Adolescents with potential PIU had an increased likelihood of concomitantly presenting with hyperactivity (OR: 4.39; 95% CI: 2.03-9.52) and conduct (OR: 2.56; 95% CI: 1.46-4.50) problems. Moreover, adolescent PIU was significantly associated with hyperactivity (OR: 9.96; 95% CI: 1.76-56.20) and conduct (OR: 8.39; 95% CI: 2.04-34.56) problems, as well as comprehensive psychosocial maladjustment (OR: 8.08; 95% CI: 1.44-45.34). Conclusions The determinants of potential PIU and PIU include accessing the internet for the purposes of retrieving sexual information, game playing, and socialization. Furthermore, both potential PIU and PIU are adversely associated with notable behavioral and social maladjustment among adolescents. PMID:21794167

  11. Self-Esteem and Problematic Drinking in China: A Mediated Model

    PubMed Central

    Zhai, Hui; Yang, Yanjie; Sui, Hong; Wang, Wenbo; Chen, Lu; Qiu, Xiaohui; Yang, Xiuxian; Qiao, Zhengxue; Wang, Lin; Zhu, Xiongzhao; Yang, Jiarun

    2015-01-01

    Background Although self-esteem is related to problematic drinking, the mechanisms by which it affects drinking remain unclear. The purpose of this study was to determine whether coping mechanisms mediate the relationship between self-esteem and problematic drinking among Chinese men and women with alcohol use disorders and to recommend appropriate interventions for drinking problems. Methods A cross-sectional survey was conducted in Harbin, Heilongjiang Province, China. A sample of 5,689 community residents was screened, and 517 male and 172 female problematic drinkers were chosen to participate in this study. A self-esteem scale, a coping questionnaire and an alcohol use disorder identification test were completed in order to assess participants’ self-esteem, coping mechanisms and alcohol use disorders, respectively. Participants’ socio-demographic data were also gathered at this stage. The resulting data were examined via descriptive statistics, correlations and bootstrap analyses. Results Lower self-esteem levels were related to problematic drinking, and there were no gender differences in the relationship between self-esteem and problematic drinking. A relationship between low self-esteem and negative coping was observed only in men. Negative coping thus mediated the relationship between self-esteem and problematic drinking among men, but this was not the case for women. Positive coping did not mediate the relationship between self-esteem and problematic drinking among the participants, regardless of gender. Conclusions Self-esteem and coping strategies are correlated among problematic drinkers. In addition, there are gender differences in the manners in which negative coping mediates the relationship between self-esteem and problematic drinking. Problematic drinking interventions directed at males should simultaneously address low self-esteem and negative coping. PMID:26451595

  12. Exploring Associations between Problematic Internet Use, Depressive Symptoms and Sleep Disturbance among Southern Chinese Adolescents

    PubMed Central

    Tan, Yafei; Chen, Ying; Lu, Yaogui; Li, Liping

    2016-01-01

    The primary aim of this study was to examine associations between problematic Internet use, depression and sleep disturbance, and explore whether there were differential effects of problematic Internet use and depression on sleep disturbance. A total of 1772 adolescents who participated in the Shantou Adolescent Mental Health Survey were recruited in 2012 in Shantou, China. The Chinese version of the Internet Addiction Test (IAT) was used to evaluate the prevalence and severity of Internet addiction. The Chinese version of the Pittsburgh Sleep Quality Index (PSQI), a 10-item version of the Center for Epidemiologic Studies Depression Scale (CESD-10), and other socio-demographic measures were also completed. Multiple regression analysis was used to test the mediating effect of problematic Internet use and depression on sleep disturbance. Among the participants, 17.2% of adolescents met the criteria for problematic Internet use, 40.0% were also classified as suffering from sleep disturbance, and 54.4% of students had depressive symptoms. Problematic Internet use was significantly associated with depressive symptoms and sleep disturbance. The correlation between depressive symptoms and sleep disturbance was highly significant. Both problematic Internet use (β = 0.014; Sobel test Z = 12.7, p < 0.001) and depression (β = 0.232; Sobel test Z = 3.39, p < 0.001) had partially mediating effects on sleep disturbance and depression was of greater importance for sleep disturbance than problematic Internet use. There is a high prevalence of problematic Internet use, depression and sleep disturbance among high school students in southern China, and problematic Internet use and depressive symptoms are strongly associated with sleep disturbance. This study provides evidence that problematic Internet use and depression have partially mediating effects on sleep disturbance. These results are important for clinicians and policy makers with useful information for prevention and

  13. Exploring Associations between Problematic Internet Use, Depressive Symptoms and Sleep Disturbance among Southern Chinese Adolescents.

    PubMed

    Tan, Yafei; Chen, Ying; Lu, Yaogui; Li, Liping

    2016-03-01

    The primary aim of this study was to examine associations between problematic Internet use, depression and sleep disturbance, and explore whether there were differential effects of problematic Internet use and depression on sleep disturbance. A total of 1772 adolescents who participated in the Shantou Adolescent Mental Health Survey were recruited in 2012 in Shantou, China. The Chinese version of the Internet Addiction Test (IAT) was used to evaluate the prevalence and severity of Internet addiction. The Chinese version of the Pittsburgh Sleep Quality Index (PSQI), a 10-item version of the Center for Epidemiologic Studies Depression Scale (CESD-10), and other socio-demographic measures were also completed. Multiple regression analysis was used to test the mediating effect of problematic Internet use and depression on sleep disturbance. Among the participants, 17.2% of adolescents met the criteria for problematic Internet use, 40.0% were also classified as suffering from sleep disturbance, and 54.4% of students had depressive symptoms. Problematic Internet use was significantly associated with depressive symptoms and sleep disturbance. The correlation between depressive symptoms and sleep disturbance was highly significant. Both problematic Internet use (β = 0.014; Sobel test Z = 12.7, p < 0.001) and depression (β = 0.232; Sobel test Z = 3.39, p < 0.001) had partially mediating effects on sleep disturbance and depression was of greater importance for sleep disturbance than problematic Internet use. There is a high prevalence of problematic Internet use, depression and sleep disturbance among high school students in southern China, and problematic Internet use and depressive symptoms are strongly associated with sleep disturbance. This study provides evidence that problematic Internet use and depression have partially mediating effects on sleep disturbance. These results are important for clinicians and policy makers with useful information for prevention and

  14. Ant-seed mutualisms: Can red imported fire ants sour the relationship?

    USGS Publications Warehouse

    Zettler, J.A.; Spira, T.P.; Allen, C.R.

    2001-01-01

    Invasion by the red imported fire ant, Solenopsis invicta, has had negative impacts on individual animal and plant species, but little is known about how S. invicta affects complex mutualistic relationships. In some eastern forests of North America, 30% of herbaceous species have ant-dispersed seeds. We conducted experiments to determine if fire ants are attracted to seeds of these plant species and assessed the amount of scarification or damage that results from handling by fire ants. Fire ants removed nearly 100% of seeds of the ant-dispersed plants Trillium undulatum, T. discolor, T. catesbaei, Viola rotundifolia, and Sanguinaria canadensis. In recovered seeds fed to ant colonies, fire ants scarified 80% of S. canadensis seeds and destroyed 86% of V. rotundifolia seeds. Our study is the first to document that red imported fire ants are attracted to and remove seeds of species adapted for ant dispersal. Moreover, fire ants might damage these seeds and discard them in sites unfavorable for germination and seedling establishment. ?? 2001 Elsevier Science Ltd. All rights reserved.

  15. Extrafloral nectar fuels ant life in deserts.

    PubMed

    Aranda-Rickert, Adriana; Diez, Patricia; Marazzi, Brigitte

    2014-01-01

    Interactions mediated by extrafloral nectary (EFN)-bearing plants that reward ants with a sweet liquid secretion are well documented in temperate and tropical habitats. However, their distribution and abundance in deserts are poorly known. In this study, we test the predictions that biotic interactions between EFN plants and ants are abundant and common also in arid communities and that EFNs are only functional when new vegetative and reproductive structures are developing. In a seasonal desert of northwestern Argentina, we surveyed the richness and phenology of EFN plants and their associated ants and examined the patterns in ant-plant interaction networks. We found that 25 ant species and 11 EFN-bearing plant species were linked together through 96 pairs of associations. Plants bearing EFNs were abundant, representing ca. 19 % of the species encountered in transects and 24 % of the plant cover. Most ant species sampled (ca. 77 %) fed on EF nectar. Interactions showed a marked seasonal pattern: EFN secretion was directly related to plant phenology and correlated with the time of highest ant ground activity. Our results reveal that EFN-mediated interactions are ecologically relevant components of deserts, and that EFN-bearing plants are crucial for the survival of desert ant communities. PMID:25381258

  16. The Biochemical Toxin Arsenal from Ant Venoms

    PubMed Central

    Touchard, Axel; Aili, Samira R.; Fox, Eduardo Gonçalves Paterson; Escoubas, Pierre; Orivel, Jérôme; Nicholson, Graham M.; Dejean, Alain

    2016-01-01

    Ants (Formicidae) represent a taxonomically diverse group of hymenopterans with over 13,000 extant species, the majority of which inject or spray secretions from a venom gland. The evolutionary success of ants is mostly due to their unique eusociality that has permitted them to develop complex collaborative strategies, partly involving their venom secretions, to defend their nest against predators, microbial pathogens, ant competitors, and to hunt prey. Activities of ant venom include paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities, while non-toxic functions include roles in chemical communication involving trail and sex pheromones, deterrents, and aggregators. While these diverse activities in ant venoms have until now been largely understudied due to the small venom yield from ants, modern analytical and venomic techniques are beginning to reveal the diversity of toxin structure and function. As such, ant venoms are distinct from other venomous animals, not only rich in linear, dimeric and disulfide-bonded peptides and bioactive proteins, but also other volatile and non-volatile compounds such as alkaloids and hydrocarbons. The present review details the unique structures and pharmacologies of known ant venom proteinaceous and alkaloidal toxins and their potential as a source of novel bioinsecticides and therapeutic agents. PMID:26805882

  17. The Biochemical Toxin Arsenal from Ant Venoms.

    PubMed

    Touchard, Axel; Aili, Samira R; Fox, Eduardo Gonçalves Paterson; Escoubas, Pierre; Orivel, Jérôme; Nicholson, Graham M; Dejean, Alain

    2016-01-01

    Ants (Formicidae) represent a taxonomically diverse group of hymenopterans with over 13,000 extant species, the majority of which inject or spray secretions from a venom gland. The evolutionary success of ants is mostly due to their unique eusociality that has permitted them to develop complex collaborative strategies, partly involving their venom secretions, to defend their nest against predators, microbial pathogens, ant competitors, and to hunt prey. Activities of ant venom include paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities, while non-toxic functions include roles in chemical communication involving trail and sex pheromones, deterrents, and aggregators. While these diverse activities in ant venoms have until now been largely understudied due to the small venom yield from ants, modern analytical and venomic techniques are beginning to reveal the diversity of toxin structure and function. As such, ant venoms are distinct from other venomous animals, not only rich in linear, dimeric and disulfide-bonded peptides and bioactive proteins, but also other volatile and non-volatile compounds such as alkaloids and hydrocarbons. The present review details the unique structures and pharmacologies of known ant venom proteinaceous and alkaloidal toxins and their potential as a source of novel bioinsecticides and therapeutic agents. PMID:26805882

  18. CONTROL FIRE ANTS BY USING DECAPITATING FLIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers with the USDA, ARS Biological Control of Pests Research Unit are rearing Pseudacteon curvatus, a tiny fly in the family Phoridae that parasitizes and kills imported fire ants. The flies only attack fire ants, and are not attracted to vegetables (12 kinds), fruit (13 kinds), raw meat (7 ...

  19. Ants cushion applied stress by active rearrangements

    NASA Astrophysics Data System (ADS)

    Liu, Zhongyang; Hyatt, John; Mlot, Nathan; Gerov, Michael; Fernandez-Nieves, Alberto; Hu, David

    2013-11-01

    Fire ants, Solenopsis invicta, link their bodies together to form waterproof rafts, which in turn drip, spread, and coagulate, demonstrating properties of an active material that can change state from a liquid to a solid. This soft-matter phase transition is important when the raft interacts with environmental forces such as raindrops and crashing waves. We study this active behavior through plate-on-plate rheology on the ants, extracting the active components by comparison with the rheological behavior of a collection of dead ants. In controlled shear tests, both and live and dead ants show properties of a non-Newtonian fluid, specifically, shear-thinning behavior. In oscillatory tests, live ants exhibit a rare behavior in which their storage modulus (G') and loss modulus (G'') have approximately the same value over three orders magnitudes of frequency and two orders of magnitude of strain, indicating the ants are neither fluid nor solid. In comparison, dead ants are more solid-like, with a storage modulus twice as large as their loss modulus. This striking active behavior arises from rearrangement of their bodies and storage and dissipation of energy with the ants' muscles.

  20. Urban Pest Management of Ants in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Keeping pace with the dynamic and evolving landscape of invasive ants in California presents a formidable challenge to the pest management industry. Pest management professionals (PMPs) are on the frontlines when it comes to battling these exotic ant pests, and are often the first ones to intercept ...

  1. The Complexity of Fire Ant Nestmate Recognition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire ants, Solenopsis invicta and Solenopsis richteri, were inadvertently introduced into the United States in the early 1900s and currently inhabit over 129 million hectares in Puerto Rico and twelve southern states from Texas to Virginia. Imported fire ants have also become established in isolated...

  2. Area-wide Suppression of Fire Ants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire ants, Solenopsis richteri and Solenopsis invicta, infest over 129.5 million ha in the USA. Fire ants, with their tremendous reproduction, mobility, and ability to occupy a wide range of habitats make their eradication very difficult. In the USA, rapid and extensive spread of these stinging an...

  3. Spectacular Batesian mimicry in ants

    NASA Astrophysics Data System (ADS)

    Ito, Fuminori; Hashim, Rosli; Huei, Yek Sze; Kaufmann, Eva; Akino, Toshiharu; Billen, Johan

    2004-10-01

    The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata.

  4. Spectacular Batesian mimicry in ants.

    PubMed

    Ito, Fuminori; Hashim, Rosli; Huei, Yek Sze; Kaufmann, Eva; Akino, Toshiharu; Billen, Johan

    2004-10-01

    The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata. PMID:15729761

  5. Problematizing a general physics class: Understanding student engagement

    NASA Astrophysics Data System (ADS)

    Spaid, Mark Randall

    teacher interventions during inquiry lessons which promote scientific inquiry are sometimes successful in moving students from a conforming learning approach to performing, those students usually regress to a previous orientation due to affective and conative factors, especially if they believe the instructional discourse is inadequate. When working in cooperative groups, the disparate epistemologies of students from each learning orientation category becomes problematic.

  6. Urban ants and transportation of nosocomial bacteria.

    PubMed

    Rodovalho, Cynara M; Santos, Ana L; Marcolino, Marcus T; Bonetti, Ana M; Brandeburgo, Malcon A M

    2007-01-01

    Many ant species displaying synanthropic behavior that have successfully dispersed in urban areas can cause problems in hospitals by acting as bacterial vectors. In this study, we encountered bacteria on ants collected at the Universidade Federal de Uberlândia hospital, in the campus and at households nearby. The ants were identified as Tapinoma melanocephalum (Fabricius) and Camponotus vittatus (Forel) (Hymenoptera: Formicidae) and the bacterial strains found here belong to the group of the coagulase-positive staphylococcus, coagulase-negative staphylococcus and gram negative bacilli, including antimicrobial drug-resistant strains. An investigation of the bacteria found in the ants and in the environment revealed that some ants carried non-isolated bacteria from the same environment and with high levels of resistance, evidencing the transmission potential of these insects. PMID:17710329

  7. Microtubules viewed as molecular ant colonies.

    PubMed

    Tabony, James

    2006-10-01

    Populations of ants and other social insects self-organize and develop 'emergent' properties through stigmergy in which individual ants communicate with one another via chemical trails of pheromones that attract or repulse other ants. In this way, sophisticated properties and functions develop. Under appropriate conditions, in vitro microtubule preparations, initially comprised of only tubulin and GTP, behave in a similar manner. They self-organize and develop other higher-level emergent phenomena by a process where individual microtubules are coupled together by the chemical trails they produce by their own reactive growing and shrinking. This behaviour is described and compared with the behaviour of ant colonies. Viewing microtubules as populations of molecular ants may provide new insights as to how the cytoskeleton may spontaneously develop high-level functions. It is plausible that such processes occur during the early stages of embryogenesis and in cells. PMID:16968217

  8. Uncovering the complexity of ant foraging trails.

    PubMed

    Czaczkes, Tomer J; Grüter, Christoph; Jones, Sam M; Ratnieks, Francis L W

    2012-01-01

    The common garden ant Lasius niger use both trail pheromones and memory of past visits to navigate to and from food sources. In a recent paper we demonstrated a synergistic effect between route memory and trail pheromones: the presence of trail pheromones results in experienced ants walking straighter and faster. We also found that experienced ants leaving a pheromone trail deposit less pheromone. Here we focus on another finding of the experiment: the presence of cuticular hydrocarbons (CHCs), which are used as home range markers by ants, also affects pheromone deposition behavior. When walking on a trail on which CHCs are present but trail pheromones are not, experienced foragers deposit less pheromone on the outward journey than on the return journey. The regulatory mechanisms ants use during foraging and recruitment behavior is subtle and complex, affected by multiple interacting factors such as route memory, travel direction and the presence trail pheromone and home-range markings. PMID:22482017

  9. Spatiotemporal chemotactic model for ant foraging

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Subramanian; Laurent, Thomas; Kumar, Manish; Bertozzi, Andrea L.

    2014-12-01

    In this paper, we present a generic theoretical chemotactic model that accounts for certain emergent behaviors observed in ant foraging. The model does not have many of the constraints and limitations of existing models for ants colony dynamics and takes into account the distinctly different behaviors exhibited in nature by ant foragers in search of food and food ferrying ants. Numerical simulations based on the model show trail formation in foraging ant colonies to be an emergent phenomenon and, in particular, replicate behavior observed in experiments involving the species P. megacephala. The results have broader implications for the study of randomness in chemotactic models. Potential applications include the developments of novel algorithms for stochastic search in engineered complex systems such as robotic swarms.

  10. Ants defend aphids against lethal disease.

    PubMed

    Nielsen, Charlotte; Agrawal, Anurag A; Hajek, Ann E

    2010-04-23

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

  11. Cryptococcus neoformans carried by Odontomachus bauri ants.

    PubMed

    Jesus, Mariana Santos de; Rodrigues, William Costa; Barbosa, Glaucia; Trilles, Luciana; Wanke, Bodo; Lazéra, Márcia dos Santos; Silva, Manuela da

    2012-06-01

    Cryptococcus neoformans is the most common causative agent of cryptococcosis worldwide. Although this fungus has been isolated from a variety of organic substrates, several studies suggest that hollow trees constitute an important natural niche for C. neoformans. A previously surveyed hollow of a living pink shower tree (Cassia grandis) positive for C. neoformans in the city of Rio de Janeiro, Brazil, was chosen for further investigation. Odontomachus bauri ants (trap-jaw ants) found inside the hollow were collected for evaluation as possible carriers of Cryptococcus spp. Two out of 10 ants were found to carry phenoloxidase-positive colonies identified as C. neoformans molecular types VNI and VNII. The ants may have acted as a mechanical vector of C. neoformans and possibly contributed to the dispersal of the fungi from one substrate to another. To the best of our knowledge, this is the first report on the association of C. neoformans with ants of the genus Odontomachus. PMID:22666855

  12. [The ants: a strategy of population concentration].

    PubMed

    Zakharov, A A

    2011-01-01

    Ants are provided with a balanced system of reactions either to the original paucity of socia or to their secondary depopulation. This system can be defined as a strategy of population concentration. Both a successful reproduction of workers and queen fertilization are necessary conditions for ant communities' survival and development. Thus, the anthills must be large enough to ensure optimal conditions for reproduction. It is the strategy of population concentration that is directed to an accelerated attainment (or rehabilitation) by a socium of a state of stable development by way of concentrating the existent ant staff in an accessible number of viable nests. This strategy is realized throughout the life of ant communities by way of (a) fusing the starting family cells left by founder females, (b) fusing small anthills during artificial ant migrations, (c) uniting smaller socia or their joining other anthills, (d) reintegrating the secondary anthills (fragmentants) after an exogenous fragmentation of formicaries. Pooling and the attraction of deficient demographic resources from outside form the most efficient and quickest ways of reaching or restoring the threshold density levels. By realizing this strategy, the ants solve their paramount problems of anthill or settlement conservation at any particular time, as well as of providing some prospects for ant existence in the future. These problems are so vital for ant socia that they appear to hold priority over such other characteristics of utmost importance as genetic kinship or even species identity. The priority of social basics over genetic ones is unequivocally supported through mixed formicaries. A necessary condition for the realization of the strategy of population concentration is tolerance of highly developed social systems to the diversity of forms and to deviations from the norm. The use of one and the same mechanism at all stages of the life both of an individual socium and large ant settlements is

  13. Framing the Salmonidae Family Phylogenetic Portrait: A More Complete Picture from Increased Taxon Sampling

    PubMed Central

    Crête-Lafrenière, Alexis; Weir, Laura K.; Bernatchez, Louis

    2012-01-01

    Considerable research efforts have focused on elucidating the systematic relationships among salmonid fishes; an understanding of these patterns of relatedness will inform conservation- and fisheries-related issues, as well as provide a framework for investigating evolutionary mechanisms in the group. However, uncertainties persist in current Salmonidae phylogenies due to biological and methodological factors, and a comprehensive phylogeny including most representatives of the family could provide insight into the causes of these difficulties. Here we increase taxon sampling by including nearly all described salmonid species (n = 63) to present a time-calibrated and more complete portrait of Salmonidae using a combination of molecular markers and analytical techniques. This strategy improved resolution by increasing the signal-to-noise ratio and helped discriminate methodological and systematic errors from sources of difficulty associated with biological processes. Our results highlight novel aspects of salmonid evolution. First, we call into question the widely-accepted evolutionary relationships among sub-families and suggest that Thymallinae, rather than Coregoninae, is the sister group to the remainder of Salmonidae. Second, we find that some groups in Salmonidae are older than previously thought and that the mitochondrial rate of molecular divergence varies markedly among genes and clades. We estimate the age of the family to be 59.1 MY (CI: 63.2-58.1 MY) old, which likely corresponds to the timing of whole genome duplication in salmonids. The average, albeit highly variable, mitochondrial rate of molecular divergence was estimated as ∼0.31%/MY (CI: 0.27–0.36%/MY). Finally, we suggest that some species require taxonomic revision, including two monotypic genera, Stenodus and Salvethymus. In addition, we resolve some relationships that have been notoriously difficult to discern and present a clearer picture of the evolution of the group. Our findings

  14. A new phylogeny of the Cephalaspidea (Gastropoda: Heterobranchia) based on expanded taxon sampling and gene markers.

    PubMed

    Oskars, Trond R; Bouchet, Philippe; Malaquias, Manuel António E

    2015-08-01

    The Cephalaspidea is a diverse marine clade of euthyneuran gastropods with many groups still known largely from shells or scant anatomical data. The definition of the group and the relationships between members has been hampered by the difficulty of establishing sound synapomorphies, but the advent of molecular phylogenetics is helping to change significantly this situation. Yet, because of limited taxon sampling and few genetic markers employed in previous studies, many questions about the sister relationships and monophyletic status of several families remained open. In this study 109 species of Cephalaspidea were included covering 100% of traditional family-level diversity (12 families) and 50% of all genera (33 genera). Bayesian and maximum likelihood phylogenetics analyses based on two mitochondrial (COI, 16S rRNA) and two nuclear gene markers (28S rRNA and Histone-3) were used to infer the relationships of Cephalaspidea. The monophyly of the Cephalaspidea was confirmed. The families Cylichnidae, Diaphanidae, Haminoeidae, Philinidae, and Retusidae were found non-monophyletic. This result suggests that the family level taxonomy of the Cephalaspidea warrants a profound revision and several new family and genus names are required to reflect the new phylogenetic hypothesis presented here. We propose a new classification of the Cephalaspidea including five new families (Alacuppidae, Colinatydidae, Colpodaspididae, Mnestiidae, Philinorbidae) and one new genus (Alacuppa). Two family names (Acteocinidae, Laonidae) and two genera (Laona, Philinorbis) are reinstated as valid. An additional lineage with family rank (Philinidae "Clade 4") was unravelled, but no genus and species names are available to reflect the phylogeny and formal description will take place elsewhere. PMID:25916189

  15. 'Candidatus Phytoplasma cirsii', a novel taxon from creeping thistle [Cirsium arvense (L.) Scop].

    PubMed

    Šafárová, Dana; Zemánek, Tomáš; Válová, Pavla; Navrátil, Milan

    2016-04-01

    Creeping thistle [Cirsium arvense (L.) Scop.] and dahlia (Dahlia sp.) plants showing typical symptoms of phytoplasma infection including yellowing, stunting, inflorescence and proliferation, were sampled; the presence of phytoplasma was confirmed by standard PCR using universal primers. RFLP analysis allowed classification of the detected phytoplasma strains CirYS, CirYS1 and DahlP within the 16SrXI group, the unique restriction profile F2nR2 fragment obtained in silico by iPhyClassifier indicated that they belong to the new 16SrXI-E subgroup. Genetic analysis of the 16S rRNA gene revealed that the studied strains shared less than 97.5% similarity with all of the previously described 'Candidatus Phytoplasma' species. The closest relatives are 'Candidatus Phytoplasma cynodontis' and 'Candidatus Phytoplasma oryzae' with 96.8% and 96.6% similarity. All strains studied bear three specific regions in the 16S rRNA gene, discriminating them from the other phytoplasma species. Phylogenetic analysis of the 16S rRNA and secA genes confirmed this specificity, as the creeping thistle and dahlia phytoplasma strains clustered in a distinguishable lineage group. The uniqueness of the genetic analysis agrees with the biological characterization of the studied phytoplasma strains, their host range, and geographical distribution. The strains only infect dicotyledonous plants in Europe, contrary to their closest relatives. Based on their unique properties, it could be concluded that the studied phytoplasma strains represent a discrete group that is proposed as a novel taxon 'Candidatus Phytoplasma cirsii', with strain CirYS as a reference strain. PMID:26849880

  16. Two new cytotypes reinforce that Micronycteris hirsuta Peters, 1869 does not represent a monotypic taxon

    PubMed Central

    2013-01-01

    Background The genus Micronycteris is a diverse group of phyllostomid bats currently comprising 11 species, with diploid number (2n) ranging from 26 to 40 chromosomes. The karyotypic relationships within Micronycteris and between Micronycteris and other phyllostomids remain poorly understood. The karyotype of Micronycteris hirsuta is of particular interest: three different diploid numbers were reported for this species in South and Central Americas with 2n = 26, 28 and 30 chromosomes. Although current evidence suggests some geographic differentiation among populations of M. hirsuta based on chromosomal, morphological, and nuclear and mitochondrial DNA markers, the recognition of new species or subspecies has been avoided due to the need for additional data, mainly chromosomal data. Results We describe two new cytotypes for Micronycteris hirsuta (MHI) (2n = 26 and 25, NF = 32), whose differences in diploid number are interpreted as the products of Robertsonian rearrangements. C-banding revealed a small amount of constitutive heterochromatin at the centromere and the NOR was located in the interstitial portion of the short arm of a second pair, confirmed by FISH. Telomeric probes hybridized to the centromeric regions and weakly to telomeric regions of most chromosomes. The G-banding analysis and chromosome painting with whole chromosome probes from Carollia brevicauda (CBR) and Phyllostomus hastatus (PHA) enabled the establishment of genome-wide homologies between MHI, CBR and PHA. Conclusions The karyotypes of Brazilian specimens of Micronycteris hirsuta described here are new to Micronycteris and reinforce that M. hirsuta does not represent a monotypic taxon. Our results corroborate the hypothesis of karyotypic megaevolution within Micronycteris, and strong evidence for this is that the entire chromosome complement of M. hirsuta was shown to be derivative with respect to species compared in this study. PMID:24359225

  17. Assessing Phylogenetic Relationships among Galliformes: A Multigene Phylogeny with Expanded Taxon Sampling in Phasianidae

    PubMed Central

    Wang, Ning; Kimball, Rebecca T.; Braun, Edward L.; Liang, Bin; Zhang, Zhengwang

    2013-01-01

    Galliform birds (relatives of the chicken and turkey) have attracted substantial attention due to their importance to society and value as model systems. This makes understanding the evolutionary history of Galliformes, especially the species-rich family Phasianidae, particularly interesting and important for comparative studies in this group. Previous studies have differed in their conclusions regarding galliform phylogeny. Some of these studies have suggested that specific clades within this order underwent rapid radiations, potentially leading to the observed difficulty in resolving their phylogenetic relationships. Here we presented analyses of six nuclear intron sequences and two mitochondrial regions, an amount of sequence data larger than many previous studies, and expanded taxon sampling by collecting data from 88 galliform species and four anseriform outgroups. Our results corroborated recent studies describing relationships among the major families, and provided further evidence that the traditional division of the largest family, the Phasianidae into two major groups (“pheasants” and “partridges”) is not valid. Within the Phasianidae, relationships among many genera have varied among studies and there has been little consensus for the placement of many taxa. Using this large dataset, with substantial sampling within the Phasianidae, we obtained strong bootstrap support to confirm some previously hypothesized relationships and we were able to exclude others. In addition, we added the first nuclear sequence data for the partridge and quail genera Ammoperdix, Caloperdix, Excalfactoria, and Margaroperdix, placing these taxa in the galliform tree of life with confidence. Despite the novel insights obtained by combining increased sampling of taxa and loci, our results suggest that additional data collection will be necessary to solve the remaining uncertainties. PMID:23741315

  18. Laboratory and Field Evaluations of Polyacrylamide Hydrogel Baits Against Argentine Ants (Hymenoptera: Formicidae).

    PubMed

    Rust, Michael K; Soeprono, Andrew; Wright, Sarajean; Greenberg, Les; Choe, Dong-Hwan; Boser, Christina L; Cory, Coleen; Hanna, Cause

    2015-06-01

    The development of effective baits to control the Argentine ant, Linepithema humile (Mayr), has been problematic because foragers prefer sweet liquids, while many toxicants are insoluble in water and liquid baits are generally difficult to deliver. The incorporation of thiamethoxam and sucrose solutions into a water-absorbing polyacrylamide hydrogel provides a unique and novel carrier and method of application for liquid baits. Formulations of thiamethoxam affected the size of the hydrogels, and sucrose solutions containing 0.0003% technical thiamethoxam provided hydrogels as large as those made with 25% sucrose solution or deionized water. Concentrations of thiamethoxam as low as 0.000075% in the hydrogels provided 50% kill of workers within 3 d in a laboratory setting. In small colony studies, baiting with 0.00015 and 0.000075% thiamethoxam hydrogels provided 100% mortality of workers and queens within 8 d. An enzyme-linked immunosorbent assay indicated that thiamethoxam was absorbed into the interior of the polyacrylamide matrix. The water loss rates of the hydrogels were dependent upon the relative humidity. Polyacrylamide hydrogels with >50% water loss were less attractive to ants. Field studies in highly infested areas indicated that concentrations of 0.0006 or 0.0018% thiamethoxam were more effective than 0.00015%. Hydrogels may provide a cost-effective alternative to providing aqueous baits to control Argentine ants. PMID:26470250

  19. A basic need theory approach to problematic Internet use and the mediating effect of psychological distress

    PubMed Central

    Wong, Ting Yat; Yuen, Kenneth S. L.; Li, Wang On

    2015-01-01

    The Internet provides an easily accessible way to meet certain needs. Over-reliance on it leads to problematic use, which studies show can be predicted by psychological distress. Self-determination theory proposes that we all have the basic need for autonomy, competency, and relatedness. This has been shown to explain the motivations behind problematic Internet use. This study hypothesizes that individuals who are psychologically disturbed because their basic needs are not being met are more vulnerable to becoming reliant on the Internet when they seek such needs satisfaction from online activities, and tests a model in which basic needs predict problematic Internet use, fully mediated by psychological distress. Problematic Internet use, psychological distress, and basic needs satisfaction were psychometrically measured in a sample of 229 Hong Kong University students and structural equation modeling was used to test the hypothesized model. All indices showed the model has a good fit. Further, statistical testing supported a mediation effect for psychological distress between needs satisfaction and problematic Internet use. The results extend our understanding of the development and prevention of problematic Internet use based on the framework of self-determination theory. Psychological distress could be used as an early predictor, while preventing and treating problematic Internet use should emphasize the fulfillment of unmet needs. PMID:25642201

  20. The (co-)occurrence of problematic video gaming, substance use, and psychosocial problems in adolescents

    PubMed Central

    VAN ROOIJ, ANTONIUS J.; KUSS, DARIA J.; GRIFFITHS, MARK D.; SHORTER, GILLIAN W.; SCHOENMAKERS, M. TIM; VAN DE MHEEN, DIKE

    2014-01-01

    Abstract Aims: The current study explored the nature of problematic (addictive) video gaming (PVG) and the association with game type, psychosocial health, and substance use. Methods: Data were collected using a paper and pencil survey in the classroom setting. Three samples were aggregated to achieve a total sample of 8478 unique adolescents. Scales included measures of game use, game type, the Video game Addiction Test (VAT), depressive mood, negative self-esteem, loneliness, social anxiety, education performance, and use of cannabis, alcohol and nicotine (smoking). Results: Findings confirmed problematic gaming is most common amongst adolescent gamers who play multiplayer online games. Boys (60%) were more likely to play online games than girls (14%) and problematic gamers were more likely to be boys (5%) than girls (1%). High problematic gamers showed higher scores on depressive mood, loneliness, social anxiety, negative self-esteem, and self-reported lower school performance. Nicotine, alcohol, and cannabis using boys were almost twice more likely to report high PVG than non-users. Conclusions: It appears that online gaming in general is not necessarily associated with problems. However, problematic gamers do seem to play online games more often, and a small subgroup of gamers – specifically boys – showed lower psychosocial functioning and lower grades. Moreover, associations with alcohol, nicotine, and cannabis use are found. It would appear that problematic gaming is an undesirable problem for a small subgroup of gamers. The findings encourage further exploration of the role of psychoactive substance use in problematic gaming. PMID:25317339

  1. Psychometric properties of the problematic online gaming questionnaire short-form and prevalence of problematic online gaming in a national sample of adolescents.

    PubMed

    Pápay, Orsolya; Urbán, Róbert; Griffiths, Mark D; Nagygyörgy, Katalin; Farkas, Judit; Kökönyei, Gyöngyi; Felvinczi, Katalin; Oláh, Attila; Elekes, Zsuzsanna; Demetrovics, Zsolt

    2013-05-01

    The rise and growing popularity of online games has led to the appearance of excessive gaming that in some cases can lead to physical and psychological problems. Several measures have been developed to explore the nature and the scale of the phenomenon. However, few measures have been validated psychometrically. The aim of the present study was to test the psychometric properties of the 12-item Problematic Online Gaming Questionnaire Short-Form (POGQ-SF) and to assess the prevalence of problematic online gaming. Data collection was carried out to assess the prevalence of problematic online gaming in a national representative adolescent sample by using an offline (pen and pencil) method. A total of 5,045 secondary school students were assessed (51% male, mean age 16.4 years, SD=0.9 years) of which 2,804 were gamers (65.4% male, mean age 16.4 years, SD=0.9 years). Confirmatory factor analysis was applied to test the measurement model of problematic online gaming, and latent profile analysis was used to identify the proportion of gamers whose online game use can be considered problematic. Results showed that the original six-factor model yielded appropriate fit to the data, and thus the POGQ-SF has appropriate psychometric properties. Latent profile analysis revealed that 4.6% of the adolescents belong to a high risk group and an additional 13.3% to a low risk group. Due to its satisfactory psychometric characteristics, the 12-item POGQ-SF appears to be an adequate tool for the assessment of problematic online gaming. PMID:23621688

  2. Psychometric Properties of the Problematic Online Gaming Questionnaire Short-Form and Prevalence of Problematic Online Gaming in a National Sample of Adolescents

    PubMed Central

    Pápay, Orsolya; Urbán, Róbert; Griffiths, Mark D.; Nagygyörgy, Katalin; Farkas, Judit; Kökönyei, Gyöngyi; Felvinczi, Katalin; Oláh, Attila; Elekes, Zsuzsanna

    2013-01-01

    Abstract The rise and growing popularity of online games has led to the appearance of excessive gaming that in some cases can lead to physical and psychological problems. Several measures have been developed to explore the nature and the scale of the phenomenon. However, few measures have been validated psychometrically. The aim of the present study was to test the psychometric properties of the 12-item Problematic Online Gaming Questionnaire Short-Form (POGQ-SF) and to assess the prevalence of problematic online gaming. Data collection was carried out to assess the prevalence of problematic online gaming in a national representative adolescent sample by using an offline (pen and pencil) method. A total of 5,045 secondary school students were assessed (51% male, mean age 16.4 years, SD=0.9 years) of which 2,804 were gamers (65.4% male, mean age 16.4 years, SD=0.9 years). Confirmatory factor analysis was applied to test the measurement model of problematic online gaming, and latent profile analysis was used to identify the proportion of gamers whose online game use can be considered problematic. Results showed that the original six-factor model yielded appropriate fit to the data, and thus the POGQ-SF has appropriate psychometric properties. Latent profile analysis revealed that 4.6% of the adolescents belong to a high risk group and an additional 13.3% to a low risk group. Due to its satisfactory psychometric characteristics, the 12-item POGQ-SF appears to be an adequate tool for the assessment of problematic online gaming. PMID:23621688

  3. FDTD-ANT User Manual

    NASA Technical Reports Server (NTRS)

    Zimmerman, Martin L.

    1995-01-01

    This manual explains the theory and operation of the finite-difference time domain code FDTD-ANT developed by Analex Corporation at the NASA Lewis Research Center in Cleveland, Ohio. This code can be used for solving electromagnetic problems that are electrically small or medium (on the order of 1 to 50 cubic wavelengths). Calculated parameters include transmission line impedance, relative effective permittivity, antenna input impedance, and far-field patterns in both the time and frequency domains. The maximum problem size may be adjusted according to the computer used. This code has been run on the DEC VAX and 486 PC's and on workstations such as the Sun Sparc and the IBM RS/6000.

  4. Ant-Based Cyber Security

    SciTech Connect

    Haack, Jereme N.; Fink, Glenn A.; Maiden, Wendy M.; McKinnon, Archibald D.; Templeton, Steven J.; Fulp, Errin W.

    2011-07-12

    We describe a swarming-agent-based, mixed-initiative approach to infrastructure defense where teams of humans and software agents defend cooperating organizations in tandem by sharing insights and solutions without violating proprietary boundaries. The system places human administrators at the appropriate level where they provide system guidance while lower-level agents carry out tasks humans are unable to perform quickly enough to mitigate today’s security threats. Cooperative Infrastructure Defense (CID) uses our ant-based approach to enable dialogue between humans and agents to foster a collaborative problem-solving environment, increase human situational awareness and influence using visualization and shared control. We discuss theoretical implementation characteristics along with results from recent proof-of-concept implementations.

  5. Spatial patterns in ant colonies.

    PubMed

    Theraulaz, Guy; Bonabeau, Eric; Nicolis, Stamatios C; Solé, Ricard V; Fourcassié, Vincent; Blanco, Stéphane; Fournier, Richard; Joly, Jean-Louis; Fernández, Pau; Grimal, Anne; Dalle, Patrice; Deneubourg, Jean-Louis

    2002-07-23

    The origins of large-scale spatial patterns in biology have been an important source of theoretical speculation since the pioneering work by Turing (1952) on the chemical basis of morphogenesis. Knowing how these patterns emerge and their functional role is important to our understanding of the evolution of biocomplexity and the role played by self organization. However, so far, conclusive evidence for local activation-long-range inhibition mechanisms in real biological systems has been elusive. Here a well-defined experimental and theoretical analysis of the pattern formation dynamics exhibited by clustering behavior in ant colonies is presented. These experiments and a simple mathematical model show that these colonies do indeed use this type of mechanism. All microscopic variables have been measured and provide the first evidence, to our knowledge, for this type of self-organized behavior in complex biological systems, supporting early conjectures about its role in the organization of insect societies. PMID:12114538

  6. Modeling the dynamics of ant colony optimization.

    PubMed

    Merkle, Daniel; Middendorf, Martin

    2002-01-01

    The dynamics of Ant Colony Optimization (ACO) algorithms is studied using a deterministic model that assumes an average expected behavior of the algorithms. The ACO optimization metaheuristic is an iterative approach, where in every iteration, artificial ants construct solutions randomly but guided by pheromone information stemming from former ants that found good solutions. The behavior of ACO algorithms and the ACO model are analyzed for certain types of permutation problems. It is shown analytically that the decisions of an ant are influenced in an intriguing way by the use of the pheromone information and the properties of the pheromone matrix. This explains why ACO algorithms can show a complex dynamic behavior even when there is only one ant per iteration and no competition occurs. The ACO model is used to describe the algorithm behavior as a combination of situations with different degrees of competition between the ants. This helps to better understand the dynamics of the algorithm when there are several ants per iteration as is always the case when using ACO algorithms for optimization. Simulations are done to compare the behavior of the ACO model with the ACO algorithm. Results show that the deterministic model describes essential features of the dynamics of ACO algorithms quite accurately, while other aspects of the algorithms behavior cannot be found in the model. PMID:12227995

  7. Extensional Rheology of Fire Ant Aggregates

    NASA Astrophysics Data System (ADS)

    Franklin, Scott; Kern, Matthew; Phonekeo, Sulisay; Hu, David

    We explore the extensional rheology and self-healing of fire ant (Solenopsis invicta) aggregations, mechanically entangled ensembles used to form rafts, bivouacs or bridges. Macroscopic experiments create quasi-two dimensional piles and measure the force required to impose a constant end-velocity. This force fluctuates, reminiscent of similar experiments on geometrically cohesive granular materials. Heterogeneous chains develop, with isolated ants often the sole link between top and bottom. Finally, the maximum pile strength scales sub-linearly with the number of ants, with the maximum force per ant decreasing as the pile grows. We reproduce these behaviors with a simple model that represents ants feet as discs connected by a spring (the ''leg''). Discs move randomly, and stick to one another when in contact. Discs in contact un-stick at random with a probability that decreases as the spring (leg) is stretched, modeling an ant's tendency to hold on longer when stretched. Simulations qualitatively reproduces the fluctuating force, chain formation and sublinear scaling of maximum force with particle number and give insight into underlying mechanisms that govern the ants' behaviors. Funded in part by NSF DMR #1133722.

  8. Extrafloral nectar fuels ant life in deserts

    PubMed Central

    Aranda-Rickert, Adriana; Diez, Patricia; Marazzi, Brigitte

    2014-01-01

    Interactions mediated by extrafloral nectary (EFN)-bearing plants that reward ants with a sweet liquid secretion are well documented in temperate and tropical habitats. However, their distribution and abundance in deserts are poorly known. In this study, we test the predictions that biotic interactions between EFN plants and ants are abundant and common also in arid communities and that EFNs are only functional when new vegetative and reproductive structures are developing. In a seasonal desert of northwestern Argentina, we surveyed the richness and phenology of EFN plants and their associated ants and examined the patterns in ant–plant interaction networks. We found that 25 ant species and 11 EFN-bearing plant species were linked together through 96 pairs of associations. Plants bearing EFNs were abundant, representing ca. 19 % of the species encountered in transects and 24 % of the plant cover. Most ant species sampled (ca. 77 %) fed on EF nectar. Interactions showed a marked seasonal pattern: EFN secretion was directly related to plant phenology and correlated with the time of highest ant ground activity. Our results reveal that EFN-mediated interactions are ecologically relevant components of deserts, and that EFN-bearing plants are crucial for the survival of desert ant communities. PMID:25381258

  9. The agricultural pathology of ant fungus gardens

    PubMed Central

    Currie, Cameron R.; Mueller, Ulrich G.; Malloch, David

    1999-01-01

    Gardens of fungus-growing ants (Formicidae: Attini) traditionally have been thought to be free of microbial parasites, with the fungal mutualist maintained in nearly pure “monocultures.” We conducted extensive isolations of “alien” (nonmutualistic) fungi from ant gardens of a phylogenetically representative collection of attine ants. Contrary to the long-standing assumption that gardens are maintained free of microbial pathogens and parasites, they are in fact host to specialized parasites that are only known from attine gardens and that are found in most attine nests. These specialized garden parasites, belonging to the microfungus genus Escovopsis (Ascomycota: anamorphic Hypocreales), are horizontally transmitted between colonies. Consistent with theory of virulence evolution under this mode of pathogen transmission, Escovopsis is highly virulent and has the potential for rapid devastation of ant gardens, leading to colony mortality. The specialized parasite Escovopsis is more prevalent in gardens of the more derived ant lineages than in gardens of the more “primitive” (basal) ant lineages. Because fungal cultivars of derived attine lineages are asexual clones of apparently ancient origin whereas cultivars of primitive ant lineages were domesticated relatively recently from free-living sexual stocks, the increased virulence of pathogens associated with ancient asexual cultivars suggests an evolutionary cost to cultivar clonality, perhaps resulting from slower evolutionary rates of cultivars in the coevolutionary race with their pathogens. PMID:10393936

  10. How to be an ant on figs

    NASA Astrophysics Data System (ADS)

    Bain, Anthony; Harrison, Rhett D.; Schatz, Bertrand

    2014-05-01

    Mutualistic interactions are open to exploitation by one or other of the partners and a diversity of other organisms, and hence are best understood as being embedded in a complex network of biotic interactions. Figs participate in an obligate mutualism in that figs are dependent on agaonid fig wasps for pollination and the wasps are dependent on fig ovules for brood sites. Ants are common insect predators and abundant in tropical forests. Ants have been recorded on approximately 11% of fig species, including all six subgenera, and often affect the fig-fig pollinator interaction through their predation of either pollinating and parasitic wasps. On monoecious figs, ants are often associated with hemipterans, whereas in dioecious figs ants predominantly prey on fig wasps. A few fig species are true myrmecophytes, with domatia or food rewards for ants, and in at least one species this is linked to predation of parasitic fig wasps. Ants also play a role in dispersal of fig seeds and may be particularly important for hemi-epiphytic species, which require high quality establishment microsites in the canopy. The intersection between the fig-fig pollinator and ant-plant systems promises to provide fertile ground for understanding mutualistic interactions within the context of complex interaction networks.