GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Plant clonal morphologies and spatial patterns as self-organized responses to resource-limited environments
    The Royal Society ; 2014
    In:  Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences Vol. 372, No. 2027 ( 2014-10-28), p. 20140102-
    Details
    In: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, The Royal Society, Vol. 372, No. 2027 ( 2014-10-28), p. 20140102-
    Abstract: We propose here to interpret and model peculiar plant morphologies (cushions and tussocks) observed in the Andean Altiplano as localized structures. Such structures resulting in a patchy, aperiodic aspect of the vegetation cover are hypothesized to self-organize thanks to the interplay between facilitation and competition processes occurring at the scale of basic plant components biologically referred to as ‘ramets’. (Ramets are often of clonal origin.) To verify this interpretation, we applied a simple, fairly generic model (one integro-differential equation) emphasizing via Gaussian kernels non-local facilitative and competitive feedbacks of the vegetation biomass density on its own dynamics. We show that under realistic assumptions and parameter values relating to ramet scale, the model can reproduce some macroscopic features of the observed systems of patches and predict values for the inter-patch distance that match the distances encountered in the reference area (Sajama National Park in Bolivia). Prediction of the model can be confronted in the future with data on vegetation patterns along environmental gradients so as to anticipate the possible effect of global change on those vegetation systems experiencing constraining environmental conditions.
    Type of Medium: Online Resource
    ISSN: 1364-503X , 1471-2962
    URL: Article
    DOI: 10.1098/rsta.2014.0102
    RVK:
    AX 30011
    Language: English
    Publisher: The Royal Society
    Publication Date: 2014
    detail.hit.zdb_id: 208381-4
    detail.hit.zdb_id: 1462626-3
    SSG: 11
    SSG: 5,1
    SSG: 5,21
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Observation and modelling of vegetation spirals and arcs in isotropic environmental conditions: dissipative structures in arid landscapes
    The Royal Society ; 2018
    In:  Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences Vol. 376, No. 2135 ( 2018-12-28), p. 20180026-
    Details
    In: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, The Royal Society, Vol. 376, No. 2135 ( 2018-12-28), p. 20180026-
    Abstract: We report for the first time on the formation of spirals like vegetation patterns in isotropic and uniform environmental conditions. The vegetation spirals are not waves and they do not rotate. They belong to the class of dissipative structures found out of equilibrium. Isolated or interacting spirals and arcs observed in South America (Bolivia) and North Africa (Morocco) are interpreted as a result of curvature instability that affects the circular shape of localized patches. The biomass exhibits a dynamical behaviour with arcs that transform into spirals. Interpretation of observations and of the predictions provided by the theory is illustrated by recent measurements of peculiar plant morphology (the alfa plant, or Stipa tenacissima L.) originated from northwestern Africa and the southern part of the Iberian Peninsula. This article is part of the theme issue ‘Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 2)’.
    Type of Medium: Online Resource
    ISSN: 1364-503X , 1471-2962
    URL: Article
    DOI: 10.1098/rsta.2018.0026
    RVK:
    AX 30011
    Language: English
    Publisher: The Royal Society
    Publication Date: 2018
    detail.hit.zdb_id: 208381-4
    detail.hit.zdb_id: 1462626-3
    SSG: 11
    SSG: 5,1
    SSG: 5,21
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Incidence of adult brain cancers is higher in countries where the protozoan parasite Toxoplasma gondii is common
    The Royal Society ; 2012
    In:  Biology Letters Vol. 8, No. 1 ( 2012-02-23), p. 101-103
    Details
    In: Biology Letters, The Royal Society, Vol. 8, No. 1 ( 2012-02-23), p. 101-103
    Abstract: We explored associations between the common protozoan parasite Toxoplasma gondii and brain cancers in human populations. We predicted that T. gondii could increase the risk of brain cancer because it is a long-lived parasite that encysts in the brain, where it provokes inflammation and inhibits apoptosis. We used a medical geography approach based on the national incidence of brain cancers and seroprevalence of T. gondii . We corrected reports of incidence for national gross domestic product because wealth probably increases the ability to detect cancer. We also included gender, cell phone use and latitude as variables in our initial models. Prevalence of T. gondii explained 19 per cent of the residual variance in brain cancer incidence after controlling for the positive effects of gross domestic product and latitude among nations. Infection with T. gondii was associated with a 1.8-fold increase in the risk of brain cancers across the range of T. gondii prevalence in our dataset (4–67%). These results, though correlational, suggest that T. gondii should be investigated further as a possible oncogenic pathogen of humans.
    Type of Medium: Online Resource
    ISSN: 1744-9561 , 1744-957X
    URL: Article
    DOI: 10.1098/rsbl.2011.0588
    Language: English
    Publisher: The Royal Society
    Publication Date: 2012
    detail.hit.zdb_id: 2103283-X
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Cat ownership is neither a strong predictor of Toxoplasma gondii infection nor a risk factor for brain cancer
    The Royal Society ; 2012
    In:  Biology Letters Vol. 8, No. 6 ( 2012-12-23), p. 1042-1042
    Details
    In: Biology Letters, The Royal Society, Vol. 8, No. 6 ( 2012-12-23), p. 1042-1042
    Type of Medium: Online Resource
    ISSN: 1744-9561 , 1744-957X
    URL: Article
    DOI: 10.1098/rsbl.2012.0625
    Language: English
    Publisher: The Royal Society
    Publication Date: 2012
    detail.hit.zdb_id: 2103283-X
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Expression of parasite genetic variation changes over the course of infection: implications of within-host dynamics for the evolution of virulence
    The Royal Society ; 2015
    In:  Proceedings of the Royal Society B: Biological Sciences Vol. 282, No. 1804 ( 2015-04-07), p. 20142820-
    Details
    In: Proceedings of the Royal Society B: Biological Sciences, The Royal Society, Vol. 282, No. 1804 ( 2015-04-07), p. 20142820-
    Abstract: How infectious disease agents interact with their host changes during the course of infection and can alter the expression of disease-related traits. Yet by measuring parasite life-history traits at one or few moments during infection, studies have overlooked the impact of variable parasite growth trajectories on disease evolution. Here we show that infection-age-specific estimates of host and parasite fitness components can reveal new insight into the evolution of parasites. We do so by characterizing the within-host dynamics over an entire infection period for five genotypes of the castrating bacterial parasite Pasteuria ramosa infecting the crustacean Daphnia magna . Our results reveal that genetic variation for parasite-induced gigantism, host castration and parasite spore loads increases with the age of infection. Driving these patterns appears to be variation in how well the parasite maintains control of host reproduction late in the infection process. We discuss the evolutionary consequences of this finding with regard to natural selection acting on different ages of infection and the mechanism underlying the maintenance of castration efficiency. Our results highlight how elucidating within-host dynamics can shed light on the selective forces that shape infection strategies and the evolution of virulence.
    Type of Medium: Online Resource
    ISSN: 0962-8452 , 1471-2954
    URL: Article
    DOI: 10.1098/rspb.2014.2820
    Language: English
    Publisher: The Royal Society
    Publication Date: 2015
    detail.hit.zdb_id: 1460975-7
    SSG: 12
    SSG: 25
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Strong interaction between plants induces circular barren patches: fairy circles
    The Royal Society ; 2014
    In:  Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences Vol. 372, No. 2027 ( 2014-10-28), p. 20140009-
    Details
    In: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, The Royal Society, Vol. 372, No. 2027 ( 2014-10-28), p. 20140009-
    Abstract: Fairy circles consist of isolated or randomly distributed circular areas devoid of any vegetation. They are observed in vast territories in southern Angola, Namibia and South Africa. We report on the formation of fairy circles, and we interpret them as localized structures with a varying plateau size as a function of the aridity. Their stabilization mechanism is attributed to a combined influence of the bistability between the bare state and the uniformly vegetation state, and Lorentzian-like non-local coupling that models the competition between plants. We show how a circular shape is formed, and how the aridity level influences the size of fairy circles. Finally, we show that the proposed mechanism is model-independent.
    Type of Medium: Online Resource
    ISSN: 1364-503X , 1471-2962
    URL: Article
    DOI: 10.1098/rsta.2014.0009
    RVK:
    AX 30011
    Language: English
    Publisher: The Royal Society
    Publication Date: 2014
    detail.hit.zdb_id: 208381-4
    detail.hit.zdb_id: 1462626-3
    SSG: 11
    SSG: 5,1
    SSG: 5,21
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Recurrent evolution of host-specialized races in a globally distributed parasite
    The Royal Society ; 2005
    In:  Proceedings of the Royal Society B: Biological Sciences Vol. 272, No. 1579 ( 2005-11-22), p. 2389-2395
    Details
    In: Proceedings of the Royal Society B: Biological Sciences, The Royal Society, Vol. 272, No. 1579 ( 2005-11-22), p. 2389-2395
    Abstract: The outcome of coevolutionary interactions is predicted to vary across landscapes depending on local conditions and levels of gene flow, with some populations evolving more extreme specializations than others. Using a globally distributed parasite of colonial seabirds, the tick Ixodes uriae , we examined how host availability and geographic isolation influences this process. In particular, we sampled ticks from 30 populations of six different seabird host species, three in the Southern Hemisphere and three in the Northern Hemisphere. We show that parasite races have evolved independently on hosts of both hemispheres. Moreover, the degree of differentiation between tick races varied spatially within each region and suggests that the divergence of tick races is an ongoing process that has occurred multiple times across isolated areas. As I. uriae is vector to the bacterium responsible for Lyme disease Borrelia burgdorferi sensu lato , these results may have important consequence for the epidemiology of this disease. With the increased occurrence of novel interspecific interactions due to global change, these results also stress the importance of the combined effects of gene flow and selection for parasite diversification.
    Type of Medium: Online Resource
    ISSN: 0962-8452 , 1471-2954
    URL: Article
    DOI: 10.1098/rspb.2005.3230
    Language: English
    Publisher: The Royal Society
    Publication Date: 2005
    detail.hit.zdb_id: 1460975-7
    SSG: 12
    SSG: 25
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...