Ecological optimum of ectothermic organisms: static-dynamical approach

During 20th century the majority of researchers interpreted ecological optimum as a certain combination of ambient factors which is optimal for growth, existence and reproduction of an organism. However, it was revealed in many species, that the maximum rates of various processes in an organism are achieved at various combinations of values of different factors, and under variable regimes as opposite to constant regimes. One may state that there is no well defined general concept which takes into account a bulk of data that do not conform the traditional definition of ecological optimum. Here, we show that it is necessary to make distinction between concepts of "static" and "dynamic" optima. It is needed for definition of real ecological optimum and creation of optimum conditions for given factor. We show also that it is necessary to take into account so-called delayed effects of factors. Basing on the analysis of responses of zooplankton to various temperatures and phosphoric load, we show that an optimum has "dynamic" characteristics besides previously known "static" ones, like a range of factor values on tolerance curve or a doze of factor. These "dynamic" characteristics are cyclic and stepwise changes of a factor, a directionality of factor's dynamics in case of stepwise changes and additionally, we reveal stimulating and inhibiting delayed effects of factors. Our results allow for a more detailed concept of ecological optimum, and also may stimulate investigations of quantitative contribution of various parameters of environmental factors to an ecological optimum of an organism or population

ACTIV SARS-CoV-2 registry (Analysis of Chronic Non-infectious Diseases Dynamics After COVID-19 Infection in Adult Patients). Assessment of impact of combined original comorbid diseases in patients with COVID-19 on the prognosis

Aim. Study the impact of various combinations of comorbid original diseases in patients infected with COVID-19 later on the disease progression and outcomes of the new coronavirus infection.&#x0D; Materials and methods. The ACTIV registry was created on the Eurasian Association of Therapists initiative. 5,808 patients have been included in the registry: men and women with COVID-19 treated at hospital or at home. ClinicalTrials.gov ID NCT04492384.&#x0D; Results. Most patients with COVID-19 have original comorbid diseases (oCDs). Polymorbidity assessed by way of simple counting of oCDs is an independent factor in negative outcomes of COVID-19. Search for most frequent combinations of 2, 3 and 4 oCDs has revealed absolute domination of cardiovascular diseases (all possible variants). The most unfavorable combination of 2 oCDs includes atrial hypertension (AH) and chronic heart failure (CHF). The most unfavorable combination of 3 oCDs includes AH, coronary heart disease (CHD) and CHF; the worst combination of 4 oCDs includes AH, CHD, CHF and diabetes mellitus. Such combinations increased the risk of lethal outcomes 3.963, 4.082 and 4.215 times respectively.&#x0D; Conclusion. Polymorbidity determined by way of simple counting of diseases may be estimated as a factor in the lethal outcome risk in the acute phase of COVID-19 in real practice. Most frequent combinations of 2, 3 and 4 diseases in patients with COVID-19 primarily include cardiovascular diseases (AH, CHD and CHF), diabetes mellitus and obesity. Combinations of such diseases increase the COVID-19 lethal outcome risk.</jats:p