Search results for "Adapta"
showing 10 items of 1961 documents
Sequential recruitment of the mRNA decay machinery to the iron-regulated protein Cth2 in Saccharomyces cerevisiae
2020
Post-transcriptional factors importantly contribute to the rapid and coordinated expression of the multiple genes required for the adaptation of living organisms to environmental stresses. In the model eukaryote Saccharomyces cerevisiae, a conserved mRNA-binding protein, known as Cth2, modulates the metabolic response to iron deficiency. Cth2 is a tandem zinc-finger (TZF)-containing protein that co-transcriptionally binds to adenine/uracil-rich elements (ARE) present in the 3′-untranslated region of iron-related mRNAs to promote their turnover. The nuclear binding of Cth2 to mRNAs via its TZFs is indispensable for its export to the cytoplasm. Although Cth2 nucleocytoplasmic transport is ess…
Experimental evolution in fluctuating environments: tolerance measurements at constant temperatures incorrectly predict the ability to tolerate fluct…
2015
The ability to predict the consequences of fluctuating environments on species distribution and extinction often relies on determining the tolerances of species or genotypes in different constant environments (i.e. determining tolerance curves). However, very little is known about the suitability of measurements made in constant environments to predict the level of adaptation to rapidly fluctuating environments. To explore this question, we used bacterial clones adapted to constant or fluctuating temperatures and found that measurements across a range of constant temperatures did not indicate any adaptation to fluctuating temperatures. However, adaptation to fluctuating temperatures was onl…
Physiological advantages of dwarfing in surviving extinctions in high-CO2 oceans
2015
Excessive CO 2 in the present-day ocean-atmosphere system is causing ocean acidification, and is likely to cause a severe biodiversity decline in the future, mirroring effects in many past mass extinctions. Fossil records demonstrate that organisms surviving such events were often smaller than those before, a phenomenon called the Lilliput effect. Here, we show that two gastropod species adapted to acidified seawater at shallow-water CO 2 seeps were smaller than those found in normal pH conditions and had higher mass-specific energy consumption but significantly lower whole-animal metabolic energy demand. These physiological changes allowed the animals to maintain calcification and to parti…
Adaptation to environmental changes: communities need more time than species
1998
Effects of environmental changes on communities and on species have been studied with two different types of animals: mammals and conodonts. This analysis was conducted on mammals from the ’Ubeidiya Sequence (Israel) dated to the Lower Pleistocene, and on conodonts from the quarry of Coumiac (France) dated to the Frasnian/Famennian boundary (Devonian). The main result of the analysis is that an ecological event can be subdivided. First of all there is a change in the environment that corresponds to a physical signal, the species react to this change, and afterwards the communities respond. Thus, a delay in time can be observed between the reaction of the species and the reaction of the comm…
Cross-Sensor Adversarial Domain Adaptation of Landsat-8 and Proba-V images for Cloud Detection
2021
The number of Earth observation satellites carrying optical sensors with similar characteristics is constantly growing. Despite their similarities and the potential synergies among them, derived satellite products are often developed for each sensor independently. Differences in retrieved radiances lead to significant drops in accuracy, which hampers knowledge and information sharing across sensors. This is particularly harmful for machine learning algorithms, since gathering new ground truth data to train models for each sensor is costly and requires experienced manpower. In this work, we propose a domain adaptation transformation to reduce the statistical differences between images of two…
Nonlinearities and Adaptation of Color Vision from Sequential Principal Curves Analysis
2016
Mechanisms of human color vision are characterized by two phenomenological aspects: the system is nonlinear and adaptive to changing environments. Conventional attempts to derive these features from statistics use separate arguments for each aspect. The few statistical explanations that do consider both phenomena simultaneously follow parametric formulations based on empirical models. Therefore, it may be argued that the behavior does not come directly from the color statistics but from the convenient functional form adopted. In addition, many times the whole statistical analysis is based on simplified databases that disregard relevant physical effects in the input signal, as, for instance…
Bifurcation analysis of a TaO memristor model
2019
This paper presents a study of bifurcation in the time-averaged dynamics of TaO memristors driven by narrow pulses of alternating polarities. The analysis, based on a physics-inspired model, focuses on the stable fixed points and on how these are affected by the pulse parameters. Our main finding is the identification of a driving regime when two stable fixed points exist simultaneously. To the best of our knowledge, such bistability is identified in a single memristor for the first time. This result can be readily tested experimentally, and is expected to be useful in future memristor circuit designs.
Hierarchical Gompertzian growth maps with application in astrophysics
2010
The Gompertz model describes the growth in time of the size of significant quantities associated to a large number of systems, taking into account nonlinearity features by a linear equation satisfied by a nonlinear function of the size. Following this scheme, we introduce a class of hierarchical maps which describe discrete sequences of intermediate characteristic scales. We find the general solutions of the maps, which account for a rich set of possible phenomena. Eventually, we provide an important application, by showing that a map belonging to the class so introduced generates all the observed astrophysical length and mass scales.
A longitudinal test of the effects of Facebook use on cultural adaptation
2015
The present study is a longitudinal examination of the role of Facebook on the cultural adaptation of Muslim immigrants to the United States (n = 379). Immigrants’ use of Facebook affects interactions with the dominant culture and with the ingroup. Respondents were asked about their use of Facebook, motivation to culturally adapt, and perceptions of the US at two different points in a 6-year period. Analysis revealed the following. Muslim immigrants to the US from 2006 to 2012 who used Facebook more for social interaction with the ingroup were less likely to be motivated to culturally adapt to the US dominant culture and these same immigrants were more likely to have a negative perception o…
PRODUCTION FLEXIBILITY AND ADAPTING TO MARKET CHANGES
2007
Abstract This paper describes those situations when a company, an organization, in its search for minimum costs, including those involved by investment, and production flexibility, manages to adapt to those changes that ensure survival on the market. Economies of scale are an attraction for any firm and thus globalized, huge firms emerge, conquering continuously developing markets. However, smaller firms face market changes that are usually dangerous in terms of sustainability. The paper highlights those market components that provide information on adapting production through flexibility.