Search results for "OPF"

Modelling prey-predator interactions in Messina beachrock pools

2020

Abstract The Strait of Messina (Sicily, Italy) attracts the interest of marine ecologists for the presence of a large variety of habitat and mutually-interacting communities. Among them, beachrock formations, despite their wide geographic distribution, which also includes the Mediterranean area, have been poorly investigated from the biotic viewpoint. In this paper, the spatial and seasonal variability of benthic megafauna from the Messina microtidal beachrock is described. Combining in situ collected data (measurements of abiotic parameters and underwater visual census) with theoretical post-processing analyses (analysis of similarity percentages and cluster analysis), we deduced the possi…

Dynamical Features of the MAP Kinase Cascade

2017

The MAP kinase cascade is an important signal transduction system in molecular biology for which a lot of mathematical modelling has been done. This paper surveys what has been proved mathematically about the qualitative properties of solutions of the ordinary differential equations arising as models for this biological system. It focuses, in particular, on the issues of multistability and the existence of sustained oscillations. It also gives a concise introduction to the mathematical techniques used in this context, bifurcation theory and geometric singular perturbation theory, as they relate to these specific examples. In addition further directions are presented in which the application…

Lethal systemic and brain infection caused by Prototheca zopfii algae in a patient with acute myeloid leukemia

2021

Systemic protothecosis is an exceptionally rare cause of sepsis with few available therapeutic options. Here, we report on a female patient with newly diagnosed acute myeloid leukemia who died after start of chemotherapy due to a severe septic shock caused by a disseminated systemic infection with Prototheca zopfii including encephalitis.

Sustained oscillations in the MAP kinase cascade.

2016

Abstract The MAP kinase cascade is a network of enzymatic reactions arranged in layers. In each layer occurs a multiple futile cycle of phosphorylations. The fully phosphorylated substrate then serves as an enzyme for the layer below. This paper focuses on the existence of parameters for which Hopf bifurcations occur and generate periodic orbits. Furthermore it is explained how geometric singular perturbation theory allows to generalize results from simple models to more complex ones.

QUANTIZATION OPERATORS ON QUADRICS

2008

Dracocephalum ruyschiana L. (pie Prensas (Antonopole))

1883

Nordischer Drachenkopf: Heidekieferwald bei Presna (Antonopol); Lichte Waldhange bei Nummern (1888.10.07.) /// Ruiša pūķgalve; Atradne: viršu priežu mežs pie Prensas (Antonopole); gaiša meža nogāze pie Numernes. /// Northern Dragon-head, deposit: heather pine forest near Prensa (Antonopole); a bright forest slope near Numerne. [Attēls no LU Muzeja kolekcijas Herbarium Latvicum (RIG II); (BOT1029_21)]

Observation of Poincaré-Andronov-Hopf Bifurcation in Cyclotron Maser Emission from a Magnetic Plasma Trap.

2018

We report the first experimental evidence of a controlled transition from the generation of periodic bursts of electromagnetic radiation into the continuous-wave regime of a cyclotron maser formed in magnetically confined nonequilibrium plasma. The kinetic cyclotron instability of the extraordinary wave of weakly inhomogeneous magnetized plasma is driven by the anisotropic electron population resulting from electron cyclotron plasma heating in a MHD-stable minimum-$B$ open magnetic trap.

Kopfinansēšanas iespējas Baltijas Valstīs

2022

Bakalaura darba tēma: Kopfinansēšanas iespējas Baltijas valstīs. Kopfinansēšana tiek uzskatīta par alternatīvu tradicionālajiem finansējuma veidiem. Ar kopfinansēšanas palīdzību fiziskām un juridiskām personām ir iespējams piesaistīt finansējumu, lai realizētu inovatīvas idejas un produktus, finansētu dažādus dzīves apstākļus, kā arī kopfinansēšana ļauj jauni izveidotiem uzņēmumiem piesaistīt pašu kapitālu. Bakalaura darba mērķis: ir izpētīt kopfinansēšanas iespējas Baltijas valstīs, veikt secinājumus un izstrādāt priekšlikumus kopfinansēšanas platformu darbības uzlabošanai. Darbs sastāv no trīs daļām – teorētiskajā daļā tiek apskatīti kopfinansēšanas teorētiskie aspekti – kopfinansēšanas j…

Coexistence of single-mode and multi-longitudinal mode emission in the ring laser model

2005

A homogeneously broadened unidirectonal ring laser can emit in several longitudinal modes for large enough pump and cavity length because of Rabi splitting induced gain. This is the so called Risken-Nummedal-Graham-Haken (RNGH) instability. We investigate numerically the properties of the multi-mode solution. We show that this solution can coexist with the single-mode one, and its stability domain can extend to pump values smaller than the critical pump of the RNGH instability. Morevoer, we show that the multi-mode solution for large pump values is affected by two different instabilities: a pitchfork bifurcation, which preserves phase-locking, and a Hopf bifurcation, which destroys it.

From resurgent functions to real resummation through combinatorial Hopf algebras

2014

Pas de résumé en anglais.