scholarly journals Identifying important interaction modifications in ecological systems

Oikos ◽  
2019 ◽  
Vol 129 (2) ◽  
pp. 147-157
Author(s):  
J. Christopher D. Terry ◽  
Michael B. Bonsall ◽  
Rebecca J. Morris
Keyword(s):  
Ecological Systems ◽  
Important Interaction ◽  
Interaction Modifications

scholarly journals Identifying important interaction modifications in ecological systems

2017 ◽  
Author(s):  
J. Christopher D. Terry ◽  
Michael B. Bonsall ◽  
Rebecca J. Morris
Keyword(s):  
Potential Interaction ◽  
Ecological Systems ◽  
Trophic Interaction ◽  
Additional Species ◽  
Individual Interaction ◽  
Important Interaction ◽  
Interaction Modifications ◽  
Underlying Network ◽  
Relationship Of ◽  
The Relationship

AbstractTrophic interaction modifications, where a consumer-resource link is affected by additional species, are widespread and significant causes of indirect effects in ecological networks. The sheer number of potential interaction modifications in ecological systems poses a considerable challenge, making prioritisation for empirical study essential. Here, we introduce measures to quantify the topological relationship of individual interaction modifications relative to the underlying network. We use these, together with measures for the strength of trophic interaction modifications to identify modifications that are most likely to exert significant effects on the dynamics of whole systems. Using a set of simulated food webs and randomly distributed interaction modifications, we test whether a subset of interaction modifications important for the local stability and direction of species responses to perturbation of complex networks can be identified. We show that trophic interaction modifications affecting interactions with a high biomass flux, those that connect species otherwise distantly linked, and those where high trophic-level species modify to interactions lower in the web have particular importance for dynamics. In contrast, the centrality of modifications in the network provided little information. This work demonstrates that analyses of interaction modifications can be tractable at the network scale and highlights the importance of understanding the relationship between the distributions of trophic and non-trophic effects.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

Ecological Systems of the Geobiosphere

1986 ◽  
Author(s):  
Heinrich Walter ◽  
Siegmar-W. Breckle
Keyword(s):  
Ecological Systems

SPIRITUAL ISLAM SUNDA DALAM TRADISI HAJAT SOLOKAN

1970 ◽  
Vol 9 (1) ◽  
pp. 98-112
Author(s):  
Imam Setyobudi
Keyword(s):  
Empirical Evidence ◽  
Ecological Systems ◽  
Rice Fields ◽  
Religious Values

This article is the ethnographic notes on leutik Hajat Solokan, aritual ceremony of farmers in Babakan Dago, Rancakalong district,Sumedang West Jawa. This ceremony reflects wisdom values, such asprotecting and maintaining ecological systems which supports their mainjobs, cultivating rice fields. This article provides empirical evidence aboutculture system which packing religious values in order to make it sturdyand stay longer. The writer also found acculturation among some religiousvalues, Hinduism, Chinese, and Islam.

Investigating the influence of aromatic moieties on the formulation of hydrophobic natural products and drugs in poly(2-oxazoline) based amphiphiles

2018 ◽  
Author(s):  
Robert Luxenhofer ◽  
Michael M Lübtow ◽  
Lukas Hahn ◽  
Thomas Lorson ◽  
Rainer Schobert
Keyword(s):  
Natural Products ◽  
Small Molecules ◽  
Water Solubility ◽  
Drug Loading ◽  
High Drug ◽  
Long Term Stability ◽  
Aromatic Content ◽  
Important Interaction ◽  
Amorphous Structures ◽  
High Drug Loading

Many natural compounds with interesting biomedical properties share one physicochemical property, namely a low water solubility. Polymer micelles are, among others, a popular means to solubilize hydrophobic compounds. The specific molecular interactions between the polymers and the hydrophobic drugs are diverse and recently it has been discussed that macromolecular engineering can be used to optimize drug loaded micelles. Specifically, π-π stacking between small molecules and polymers has been discussed as an important interaction that can be employed to increase drug loading and formulation stability. Here, we test this hypothesis using four different polymer amphiphiles with varying aromatic content and various natural products that also contain different relative amounts of aromatic moieties. While in the case of paclitaxel, having the lowest relative content of aromatic moieties, the drug loading decreases with increasing relative aromatic amount in the polymer, the drug loading of curcumin, having a much higher relative aromatic content, is increased. Interestingly, the loading using schizandrin A, a dibenzo[a,c]cyclooctadiene lignan with intermediate relative aromatic content is not influenced significantly by the aromatic content of the polymers employed. The very high drug loading, long term stability, the ability to form stable highly loaded binary coformulations in different drug combinations, small sized formulations and amorphous structures in all cases, corroborate earlier reports that poly(2-oxazoline) based micelles exhibit an extraordinarily high drug loading and are promising candidates for further biomedical applications. The presented results underline that the interaction between the polymers and the incorporated small molecules are complex and must be investigated in every specific case.<br>

Commons Research and Pastoralism in the Context of Variability

2020 ◽  
Vol 24 (2) ◽  
pp. 272-285
Author(s):  
Jill Philine Blau
Keyword(s):  
Ecological Systems ◽  
Potential Problems ◽  
Pastoral Management ◽  
The Commons

Research has shown that pastoralism and the management of the commons are connected (Bollig and Lesogorol 2016). In this article I discuss how the concept of variability, which emerged from discussions of dryland ecologies in the 1980s (Homewood 2008), can inform and enhance research on the commons and vice versa. Research on the commons can further elucidate the understanding of pastoralist practices. I conclude with reflections drawn from some empirical examples in the literature, the use of the socio-ecological systems (SES) framework, and discuss the benefits and potential problems when applied to heterogeneous and flexible pastoralist practices and to the pastoral management of the commons.

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