Search results for "Dominance"
showing 10 items of 360 documents
Meson loops in the $f_0(980)$ and $a_0(980)$ radiative decays into $\rho$, $\omega$
2008
We calculate the radiative decay widths of the $a_0(980)$ and $f_0(980)$ scalar mesons into $\rho\gamma$ and $\omega\gamma$ considering the dynamically generated nature of these scalar resonances within the realm of the Chiral Unitary Approach. The main ingredient in the evaluation of the radiative width of the scalar mesons are the loops coming from the decay into their constituent pseudoscalar-pseudoscalar components and the subsequent radiation of the photon. The dominant diagrams with only pseudoscalar mesons in the loops are found to be convergent while the divergence of those with a vector meson in the loop are written in terms of the two meson loop function easily regularizable. We p…
Exogenous introduction of an immunodominant peptide from the non-structural IE1 protein of human cytomegalovirus into the MHC class I presentation pa…
2008
Exogenous introduction of particle-associated proteins of human cytomegalovirus (HCMV) into the major histocompatibility complex (MHC) class I presentation pathway by subviral dense bodies (DB) is an effective way to sensitize cells against CD8 T-cell (CTL) recognition and killing. Consequently, these particles have been proposed as a platform for vaccine development. We have developed a strategy to refine the antigenic composition of DB. For proof of principle, an HCMV recombinant (RV-VM3) was generated that encoded the immunodominant CTL determinant IE1TMY from the IE1 protein in fusion with the major constituent of DB, the tegument protein pp65. To generate RV-VM3, a bacterial artificial…
Species richness-standing crop relationship in stream bryophyte communities: patterns across multiple scales
2001
Summary 1 We tested for a unimodal (‘hump-backed’) relationship between species richness and standing crop at various spatial scales in stream bryophyte communities. Bryophyte species and their biomasses were determined from 20 to 25 quadrats in eight river and six stream sites in northern Finland. 2 Regression analyses revealed a quadratic relationship between richness and biomass in only two of the river sites and a positive correlation in one other. A quadratic relationship was detected in three stream sites and richness increased linearly with biomass in another. 3 We also tested for the hump-shaped pattern across individual stream boulders, representing an elevational gradient from con…
Calculus of Contextual Rough Sets in Contextual Spaces
1998
ABSTRACT The palier explains the methods of approximation of set which were earlier put forth by the authors (1995a, 1995b) and by W. Marek and H. Rasiowa (1986). An essential part of this paper is devoted to the presentation of a certain calculus of rough sets and contextual rough sets in contextual spaces.
The duality of ocean acidification as a resource and a stressor
2018
Ecologically dominant species often define ecosystem states, but as human disturbances intensify, their subordinate counterparts increasingly displace them. We consider the duality of disturbance by examining how environmental drivers can simultaneously act as a stressor to dominant species and as a resource to subordinates. Using a model ecosystem, we demonstrate that CO2-driven interactions between species can account for such reversals in dominance; i.e., the displacement of dominants (kelp forests) by subordinates (turf algae). We established that CO2 enrichment had a direct positive effect on productivity of turfs, but a negligible effect on kelp. CO2 enrichment further suppressed the …
Ocean acidification as a driver of community simplification via the collapse of higher-order and rise of lower-order consumers
2017
AbstractIncreasing oceanic uptake of CO2 is predicted to drive ecological change as both a resource (i.e. CO2 enrichment on primary producers) and stressor (i.e. lower pH on consumers). We use the natural ecological complexity of a CO2 vent (i.e. a seagrass system) to assess the potential validity of conceptual models developed from laboratory and mesocosm research. Our observations suggest that the stressor-effect of CO2 enrichment combined with its resource-effect drives simplified food web structure of lower trophic diversity and shorter length. The transfer of CO2 enrichment from plants to herbivores through consumption (apparent resource-effect) was not compensated by predation, becaus…
Effects of fish-farm biodeposition on periphyton assemblages on artificial substrates in the southern Tyrrhenian Sea (Gulf of Castellammare, Sicily)
2007
An algal assemblage growing on artificial substrata of fish-farm cages was investigated. Specifically, algal response to the effects of fish-farm facilities was studied, in order to identify a possible future descriptor of biodeposition impact. Some sites were positioned upstream of the farms (at least 750 m; ‘controls’) and other sites were positioned downstream of the farms (‘impacts’). All sites were situated in the Tyrrhenian Sea. Control and impact sites differed significantly with regard to the dissolved nutrient profile. The fouling community (samples were scraped from buoys) displayed a reduction gradient in diversity which increased with the effect of fish farms. A total of 51 taxa…
Nematode community response to fish-farm impact in the western Mediterranean.
2002
A previous investigation on fish-farm biodeposition effects on benthos, carried out in the Gaeta Gulf (northwestern Mediterranean Sea), revealed a strong impact on meiofaunal assemblages. This study implements these findings by examining in detail the nematode assemblage and its response to organic enrichment from the start of a fish farm activity to the conclusion of the fish rearing cycle. Density, community structure and individual size were utilised for univariate (genus, trophic diversity and abundance patterns) and multivariate analyses (MDS) in order to identify the best descriptors of impact and the response of the nematode assemblages. Nematodes displayed significantly reduced dens…
Enzymatically hydrolyzable protein and carbohydrate sedimentary pools as indicators of the trophic state of detritus sink system: a case study in a M…
2003
In order to classify the trophic state of 'detritus sink' systems, instead of the conventional indicators based on inorganic nutrient availability and algal biomass and productivity in the water column, we utilized new biochemical descriptors based on the amount of sedimentary organic carbon and nitrogen potentially available to heterotrophic nutrition. We investigated spatial and temporal changes in microphytobenthic biomass, organic matter biochemical composition and enzymatically hydrolyzable protein and carbohydrate pools along a N-S transect in the Marsala lagoon (Mediterranean Sea, Italy) at three stations characterized by different hydrodynamic conditions and organic matter content i…
Coherent Conditional Previsions and Proper Scoring Rules
2012
In this paper we study the relationship between the notion of coherence for conditional prevision assessments on a family of finite conditional random quantities and the notion of admissibility with respect to bounded strictly proper scoring rules. Our work extends recent results given by the last two authors of this paper on the equivalence between coherence and admissibility for conditional probability assessments. In order to prove that admissibility implies coherence a key role is played by the notion of Bregman divergence.