28 research outputs found
Pullback permanence in a non-autonomous competitive LotkaâVolterra model
AbstractThe goal of this work is to study in some detail the asymptotic behaviour of a non-autonomous LotkaâVolterra model, both in the conventional sense (as tââ) and in the âpullbackâ sense (starting a fixed initial condition further and further back in time). The non-autonomous terms in our model are chosen such that one species will eventually die out, ruling out any conventional type of permanence. In contrast, we introduce the notion of âpullback permanenceâ and show that this property is enjoyed by our model. This is not just a mathematical artifice, but rather shows that if we come across an ecology that has been evolving for a very long time we still expect that both species are represented (and their numbers are bounded below), even if the final fate of one of them is less happy. The main tools in the paper are the theory of attractors for non-autonomous differential equations, the sub-supersolution method and the spectral theory for linear elliptic equations
The sub-supertrajectory method. Application to the nonautonomous competition Lotka-Volterra model
In this paper we study in detail the pullback and forwards attractions to non-autonomous competition Lotka-Volterra system. In particular, under some conditions on the parameters, we prove the existence of a unique non-degenerate global solution for these models, which attracts any other complete bounded trajectory. For that we present the sub-supertrajectory tool as a generalization of the now classical subsupersolution method
Scaf1 promotes respiratory supercomplexes and metabolic efficiency in zebrafish
The oxidative phosphorylation (OXPHOS) system is a dynamic
system in which the respiratory complexes coexist with superassembled quaternary structures called supercomplexes (SCs). The
physiological role of SCs is still disputed. Here, we used zebrafish
to study the relevance of respiratory SCs. We combined immunodetection analysis and deep data-independent proteomics to
characterize these structures and found similar SCs to those
described in mice, as well as novel SCs including III2 + IV2, I + IV,
and I + III2 + IV2. To study the physiological role of SCs, we generated two null allele zebrafish lines for supercomplex assembly
factor 1 (scaf1). scaf1 / fish displayed altered OXPHOS activity
due to the disrupted interaction of complexes III and IV. scaf1 /
fish were smaller in size and showed abnormal fat deposition and
decreased female fertility. These physiological phenotypes were
rescued by doubling the food supply, which correlated with
improved bioenergetics and alterations in the metabolic gene
expression program. These results reveal that SC assembly by Scaf1
modulates OXPHOS efficiency and allows the optimization of
metabolic resources.Microscopy Imaging Center of the University of BernSpanish Ministry of Economy and Competitiveness, MINECO
SAF2015-65633-RSpanish Ministry of Economy and Competitiveness, MINECO
SAF2015-65633-RHuman Frontier Science Program
RGP0016/2018European Research Council (ERC)
337703SNF
31003A-159721Swiss National Science Foundation (SNSF)
320030_170062MINECO
BIO2015-67580-PCarlos III Institute of Health-Fondo de Investigacion Sanitaria)
PRB3
IPT17/0019Fundacion La Marato TV3La Caixa Foundation
HR17-00247Ministry of Economy, Industry and Competitiveness (MEIC)Pro-CNIC FoundationSevero Ochoa Center of Excellence (MEIC award)
SEV-2015-050
Existence and nonexistence of unbounded forwards attractor for a class of non-autonomous reaction diffusion equations.
The goal of this work is to study the forward dynamics of positive solutions for the nonautonomous logistic equation ut â _u = _u â b(t)up, with p > 1, b(t) > 0, for all t 2 R, limt!1 b(t) = 0. While the pullback asymptotic behaviour for this equation is now well understood, several different possibilities are realised in the forward asymptotic regime
Microbial additives affect silage quality and ruminal dry matter degradability of avocado (Persia Americana) pulp silage
This study evaluated effects of microbial inoculation on fermentation, aerobic stability and ruminal dry matter (DM) degradation of silage produced from Avocado (Persia Americana) pulp (AP). The AP, 800 g/kg fresh matter (FM) was mixed with 150 g grape pumice (GP)/kg FM and 50 g sugarcane molasses/kg FM. The mixture was treated with 1) no inoculant (control), 2) Emsilage inoculant (EMS), and 3) Sil-All 4x4 W.S. inoculant (SIL). Materials were ensiled in 1.5 L anaerobic jars for 90 days. Triplicate samples were collected on days 0, 3, 7, 10, and 90 for determination of fermentation, nutritive value and aerobic stability. In situ DM degradability was determined using 3 rumen cannulated Holstein cows. Microbial inoculation to AP silage increased lactic acid bacteria population, which subsequently increased residual fermentation substrate and lactic acid content. Terminal pH and volatile fatty acids of the silage were not affected by inoculation. Inoculated silage had less fibre and reduced aerobic stability compared to the control. The AP and its mixture had higher DM soluble fractions compared to the GP which had a higher degradation rate. Potential degradable fraction and extent of degradation were similar for each treatment. The EMS treatment had higher soluble fractions and lower degradation rate than other treatments. Inoculation with SIL improved degradation of the silage compared to other treatments. Thus, microbial inoculation qualifies the AP silage as a potential feed for ruminants.
Keywords: feed, grape pomace, inoculant, oil cake, organic aci