Search results for "Adaptive"
showing 10 items of 792 documents
Loss of histone macroH2A1 in hepatocellular carcinoma cells promotes paracrine-mediated chemoresistance and CD4+CD25+FoxP3+ regulatory T cells activa…
2020
Rationale: Loss of histone macroH2A1 induces appearance of cancer stem cells (CSCs)-like cells in hepatocellular carcinoma (HCC). How CSCs interact with the tumor microenvironment and the adaptive immune system is unclear. Methods: We screened aggressive human HCC for macroH2A1 and CD44 CSC marker expression. We also knocked down (KD) macroH2A1 in HCC cells, and performed integrated transcriptomic and secretomic analyses. Results: Human HCC showed low macroH2A1 and high CD44 expression compared to control tissues. MacroH2A1 KD CSC-like cells transferred paracrinally their chemoresistant properties to parental HCC cells. MacroH2A1 KD conditioned media transcriptionally reprogrammed parental …
Dietary divergence in space and time – Lessons from the dwarf-goat Myotragus balearicus (Pleisto-Holocene, Mallorca, Spain)
2013
8 pages; International audience; Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are prone to facilitate ecological separation which might lead to an adaptive radiation. Examples of such radiations can be found in the Mediterranean for the genera Candiacervus (Crete), Nesogoral (Sardinia) and Hoplitomeryx (Gargano). A different strategy to cope with limited resources on islands is generalism. We test whether populations of the endemic bovid Myotragus balearicus from two sites and Pleistocene as well as Holocene levels on Mallorca island displays ecological separation indicated by diet, or whether the species shifted its dietary trait towards general…
Niche filling slows the diversification of Himalayan songbirds.
2013
In Himalayan songbirds, the speciation rate is ultimately set by ecological competition, rather than by the rate of acquisition of reproductive isolation. The beginnings of adaptive radiation and speciation have been widely studied — in Darwin's finches, sticklebacks and cichlid fish, for example — but relatively little is known about what happens next. Specifically, what is the rate-limiting step for the establishment of new species? This seven-year study of the 358 songbird species found on the Himalayan slopes suggests that it is the rates at which new niches are created and occupied that limits diversification, not the rate at which new species form through reproductive isolation. Speci…
'Niche Selection' and the evolution of a complex behavior in a changing environment--a simulation.
2000
One of the key problems in theoretical biology is the identification of the mechanisms underlying the evolution of complexity. This paper suggests that some difficulties in current models could be avoided by taking account of “niche selection” as proposed by Waddington [21] and subsequent authors [2]. Computer simulations, in which an evolving population of artificial organisms “selects” the niche(s) that maximize their fitness, are compared with a Control Model in which “Niche Selection” is absent. In the simulations the Niche Selection Model consistently produced a greater number of “fit” organisms than the Control Model; although the Niche Selection Model tended, in general, to produce o…
Long-term ecology of investors in a financial market
2018
AbstractThe cornerstone of modern finance is the efficient market hypothesis. Under this hypothesis all information available about a financial asset is immediately incorporated into its price dynamics by fully rational investors. In contrast to this hypothesis many studies have pointed out behavioral biases in investors. Recently it has become possible to access databases that track the trading decisions of investors. Studies of such databases have shown that investors acting in a financial market are highly heterogeneous among them, and that heterogeneity is a common characteristic of many financial markets. The article describes an empirical study of the daily trading decisions of all Fi…
Differences in parasite community composition support ecological differentiation in a freshwater gadoid fish
2022
Several northern freshwater fishes have gone through rapid adaptive radiation after the last glacial period, resulting in new species or intraspecific morphs with distinct life histories. Parasite infections can promote adaptive radiations and spatiotemporal differences in patterns of infections can potentially reveal incipient or ongoing speciation processes. We investigated intraspecific differentiation in a freshwater gadoid fish, burbot (Lota lota), by exploring differences in parasite infections between two potential life-history morphs in Lake Konnevesi, Central-Finland, one reproducing species characteristically in shallow littoral waters in February and the other possibly in deep pr…
Community currency (CCs) in Spain: An empirical study of their social effects
2016
Despite its sudden proliferation along the economic crisis period, no previous study has investigated the social effects of the community currency (CCs) experiences in Spain. Previous research on CCs experiences from different countries provided evidences about social capital improvement, introducing CCs as sustainability tools. This research uses the theoretical frameworks of social capital and complex adaptive systems to approach concepts like sustainability, networks, trust, norms, participation and cooperation. Statistical analysis of the data collected in June 2013 through online survey explores social capital and resilience indicators among the Spanish exchange community users, conclu…
Cyber World as a Social System
2015
The increasing applying of information and communication technology is transforming the society into an unknown ground of the continuously evolving cyber world. This challenges the actors of the society and has increased complexity. The purpose of this chapter is to form a hypothesis about how to identify patterns i.e., emergent phenomena about the cyber world for developing security in the society. The cyber world is considered as a complex adaptive system. A system modelling approach to complex adaptive systems is briefly outlined and a social system model of a society is introduced as a content analysis method to complex adaptive systems. The model is populated with a small set of empiri…
Examining five pathways on how self-control is associated with emotion regulation and affective well-being in daily life.
2020
OBJECTIVE Self-control is positively connected to well-being, but less is known about what, on the mechanistic level, explains this association. We hypothesized five pathways how this connection could be explained by emotion regulation, that is, by facilitating (a) strategy effectiveness, (b), adaptive strategy selection, (c) situation selection, (d) strategy variability, or (e) social sharing. METHOD To explore these pathways, we integrated two ambulatory assessment data sets (N = 250 participants, N = 22,796 observations) that included assessments of participants' emotions and their emotion regulation efforts. RESULTS We found that self-control was positively associated with affective wel…
Evaluating the Performance of Real Time Videoconferencing in Ad Hoc Networks Through Emulation
2008
The validation of new video protocols and applications for mobile ad hoc networks in a real environment is an important task. In this work we present Castadiva, a test-bed architecture that allows validating software solutions for ad hoc networks using low-cost, off-the-shelf devices and open source software. We use this tool to test a videocall using the OLSR protocol in different scenarios, varying the number of hops between the caller and the receiver. The results obtained in this paper show that, for an ad hoc network with a large number of hops, the quality of videocalls suffers a significant degradation even in the absence of mobility.