Predicting forest grouse distribution taking account of spatial autocorrelation

Spatially explicit, multi-scale models for predictions of species potential distribution can be useful tools for integrating biodiversity considerations in planning and strategic environmental assessment. In such models, the occurrences of focal species are related to habitat and landscape variables, which in urbanising areas should also include effects of urban disturbances. Moreover, the accuracy of the spatial predictive models may be affected by spatial autocorrelation, which means that a part of the variance is explained by neighbouring values. The aim of this study was to explore the effects of habitat and disturbance patterns on the distribution of two forest grouse species, Tetrao urogallus and Bonasa bonasia, and to detect and model the effects of spatial autocorrelation. The distribution of the two species could be explained in terms of reduction of a main predator, habitat quality, quantity and connectivity, including urban disturbances. The residuals of the initial regressions showed positive spatial autocorrelation that could be quantified by using a spatial probit model. The application of the spatial probit model revealed strongly significant spatial dependencies for both species. Furthermore, the model fit could be increased for T. urogallus by applying this model. The results implied that both species distributions might be affected by both reactions to the underlying land-use pattern, but also by interaction with neighbours. The use of the spatial probit model is a way to incorporate spatial interactions that otherwise cannot be captured by the independent variables.     

Molecular-modeling calculations of enzymatic enantioselectivity taking hydration into account

A new molecular-modeling methodology has been applied to explain enzymatic enantioselectivity in water. This methodology, which combines vacuum molecular mechanics and the continuum solvation method, should provide a more realistic view of the solvent-enzyme and solvent-substrate interactions than the heretofore used approaches involving the vacuum molecular mechanics only. The methodology described herein has been validated using the experimental data on alpha-chymotrypsin's enantioselectivity in the hydrolysis of four chiral substrates. The reasons why the vacuum molecular mechanics, although not taking hydration into account, still in most cases provide a satisfactory approximation of reality are discussed.     

Multiple Mantel tests and isolation-by-distance, taking into account long-term historical divergence

Mantel tests of matrix correspondence have been widely used in population genetics to examine microevolutionary processes, such as isolation-by-distance (IBD). We used partial and multiple Mantel tests to simultaneously test long-term historical effects and current divergence and equilibrium processes, such as IBD. We used these procedures to calculate genetic divergence among Eugenia dysenterica (Myrtaceae) populations in Central Brazil. The Nei's genetic distances between pairs of local populations were strongly correlated with geographic distances, suggesting an IBD process, but field observations and the geographic distribution of the samples suggest that populations may have been subjected to more complex evolutionary processes of genetic divergence. Partial Mantel regression was used to partition the effects of geographic structure and long-term divergence associated with a possible historical barrier. The R(2) of the model with both effects was 73.3%, and after the partition 21.9% of the variation in the genetic distances could be attributed to long-term historical divergence alone, whereas only 1.5% of the variation in genetic distances could be attributed to IBD. As expected, there was a large overlap between these processes when explaining genetic divergence, so it was not possible to entirely partition divergence between historical and contemporary processes.     

Modelling of continuous microbial cultivation taking into account the memory effects

The problem of chemostat dynamics modelling for the purpose of control is considered. The "memory" of the culture is explicitly taken into account. Two possibilities for improving the quality of the proposed modelling approaches are discussed. A general model that accounts for the culture `memory' by means of different `memory' functions in the expressions of the specific growth rate and of the specific consumption rate and a polynomial function of the substrate concentration for the yield factor is proposed. The case where the maintenance energy is taken into account is also discussed. Two modifications of the general model (w-type and S-type) are presented. A zero-order `memory' function and a i-function with delay are applied in order to describe the `memory' effects. Continuous growth of the strain Saccharomyces cerevisiae on a glucose limited medium is considered as a case study. Detailed investigations of the variety of models, derived from the general model by applying different `memory' functions and different assumptions are carried out. The results are compared with those previously reported for the same process. It is shown that a significant improvement in predicting the substrate dynamics (not accompanied by any decrease in the quality of the model with respect to the biomass concentration) could be achieved, involving a first- or second-order polynomial function for the yield factor. It is also shown that the quality of the model mainly depends on the way that `memory' function is incorporated. The detailed investigations give priority to the w-type models. In this case past values of both biomass and substrate variables are considered. The time delay models with pure (constant) delay and those which account for the culture `memory' by zero-order `memory' function (adaptability parameter) are compared with respect to their utilization for the purpose of model-based control.     

A Reed-Frost model taking into account uncertainties in the diagnostic of the infection

In this paper, we model the epidemic course of a pathogen infection within a semi-closed group which generates clinical signals which do not necessarily permit its ready and certain identification. Typical examples of such a pathogen are influenza-type viruses. We allow for time-varying infectivity levels among individuals, and model the probability of infection per contact as a function of the clinical signals. In order to accomplish this, we introduce a modified chain-binomial Reed-Frost model. We obtain an expression for the basic reproduction ratio and determine conditions which guarantee that the epidemic does not survive in the long-term. These conditions being functions of the signal’s distribution, they can be used to design and evaluate interventions, such as treatment protocols.     

An MLP training algorithm taking into account known errors on inputs and outputs

A training algorithm is introduced that takes into account a priori known errors on both inputs and outputs in an MLP network. The new cost function introduced for this case is based on a linear approximation of the network function over the input distribution for a given input pattern. Update formulas, in the form of the gradient of the new cost function, is given for a MLP network, together with expressions for the Hessian matrix. This is later used to calculate error bars in a Bayesian framework. The error bars thus derived are discussed in relation to the more commonly used width of the target posterior predictive distribution. It will also be shown that the taking into account of known input uncertainties in the way suggested in this article will have a strong regularizing effect on the solution.     

The mathematical modelling of population dynamics taking into account the adaptive behavior of individuals

The general approach for modelling of abundance dynamic of biological populations and communities is offered. The mechanisms of individual adaptation in changing environment are considered. The approach is detailed for population models without structure and with age structure. The property of solutions are investigated. As examples the author studies the concrete definitions of general models by analogy with models of Ricker and May. Theoretical analysis and calculations shows that survival of model population in extreme situation increases if adaptive behaviour is taking into account.     

Management of athletic training taking into account individual heart rate variability characteristics

This article presents a new approach to planning and timely adjusting athletic trainings according to the data of the quick analysis of heart rate variability. It has been shown that individual types of regulation are different not only in the autonomic balance, but also in the degree of endurance of training and competition loads.     

Evaluation of musculotendinous stiffness in prepubertal children and adults, taking into account muscle activity.

Musculotendinous (MT) stiffness of the triceps surae (TS) muscle group was quantified in 28 prepubertal children (7-10 yr) by using quick-release movements at different levels of submaximal contractions. Surface electromyograms (EMG) of each part of the TS and of the tibialis anterior were also recorded. A stiffness index, defined as the slope of the angular stiffness-torque relationship (SIMT-Torque), was used to quantify changes in MT stiffness with age. Results showed a significant decrease in SIMT-Torque with age, ranging from 4.02 +/- 0.29 to 2.88 +/- 0.31 rad-1 for the youngest to the oldest children. Because an increase in stiffness with age was expected due to the maturation of elastic tissues, overactivation of the TS was suspected to contribute to the higher SIMT-Torque values found in the youngest children. TS EMG-torque analyses confirmed that neuromuscular efficiency was significantly lower for the 7- or 8-yr-old children compared with 10-yr-old children, notably due to a higher degree of tibialis anterior coactivation found in the youngest children. Thus the stiffness index originally defined as the slope of the angular stiffness-EMG relationship increased significantly with age toward adult values. The results underlined the necessity to take into account the capacities of muscle activation to quantify changes in elastic properties of muscles, when those capacities are suspected to be altered.     

Assessment of the human immunological status by taking into account the correlations among individual indices

The problem of correlation of the parameters of the immune system in the normal subjects and in patients with immunological diseases has been considered. The most informative relations have been determined and an attempt has been made to reveal common and specific signs of various immunological diseases.     

Dissection of cis-regulatory elements of the Drosophila gene Serrate

 The Drosophila gene Serrate encodes a membrane spanning protein, which is expressed in a complex pattern during embryogenesis and larval stages. Loss of Serrate function leads to larval lethality, which is associated with several morphogenetic defects, including the failure to develop wings and halteres. Serrate has been suggested to act as a short-range signal during wing development. It is required for the induction of the organising centre at the dorsal/ventral compartment boundary, from which growth and patterning of the wing is controlled. In order to understand the regulatory network required to control the spatially and temporally dynamic expression of Serrate, we analysed its cis-regulatory elements by fusing various genomic fragments upstream of the reporter gene lacZ. Enhancer elements reflecting the expression pattern of endogenous Serrate in embryonic and postembryonic tissues could be confined to 26 kb of genomic DNA, including 9 kb of transcribed region. Expression in some embryonic tissues is under the control of multiple enhancers located in the 5’ region and in intron sequences. The data presented here provide the tools to unravel the genetic network which regulates Serrate during different developmental stages in diverse tissues. Received: 27 March 1998 / Accepted: 17 May 1998     

Modeling calcium-45 metabolism in tissue, taking into account the structure and hemodynamics of the capillary system]

The accumulation of Ca-45 in the tissues and the degree of its desorption during the perfusion in the sufficiently extensive limits does not depend upon the rate of the perfused solution and is the function of the perfused solution volume. Taking into account strong dependence of the volume rate of filling the capillaries with the solution upon the capilliary radii (r-4) one may come to the conclusion that Ca-45 saturation of the paracapillary spaces in the wide capillaries occurs much sooner than in the narrow ones. As a result of developing these postulates, we have got the formulae which associates these two functions. It is shown that according to the theory the accumulation and desorption processes are interrelated and may be calculated.     

Quantitative morphometric evaluation of the muscular coat of arteries taking into account their functional state

The method is suggested for the quantitative characteristics of dynamic vascular tone. It allows the determination of a degree of vascular vasoconstriction as a definite value--an index. This index is determined as real area of vascular cross-sections to their maximum possible area ratio with the inner elastic membrane fully straightened. The index determined in such a way permits to assess quantitatively the degree of vascular vasoconstriction, which is independent of the vascular diameter.     

Effectiveness of selection taking into account differences in parental couples for histocompatibility antigens

The connection of the histoincompatibility antigens, determined by the reaction in a mixed culture of lymphocytes of the pair of parents, with the litter of linear mice and live weight of cattle was studied. It was ascertained that the degree of the difference between mates for histocompatibility locus correlated with fruitfulness and productive qualities of the descendants. As a result, a greater quantity of descendants of animals, being more viable, are born. The descendants of the parents, having the high indexes of the reaction in the mixed culture of lymphocytes, are born larger and stronger and retain this advantage during succeeding life periods. The reaction in monozygotic twins has a minimum index. The index of the reaction increases when the relationship between individuals decreases. The method of mixed culture of lymphocytes can be used for prognosis of pairs' combination, for maintenance of the heterogeneity and for determination of the degree of relationship between animals.     

Improving tetanus prevention in the Krasnodar area taking the current epidemic situation into account]

An increase of percentage of elderly persons among those who fell ill with tetanus (70%) was noted against a sharp reduction of tetanus incidence under the effect of mass active immunization against this disease. A study of immunity in older and elderly individuals showed the percentage of immune persons among them to be rather low (48.8--55.6%). Due to difficulty of elderly individuals embracement by vaccination the authors suggest a single immunization scheme with a double toxoid dose (20 BU) followed by revaccination with 10 BU in one year. A total of 21 472 persons were placed under observation. The suggested immunization scheme was harmless, promoted stimulation of antitetanus immunity in persons vaccinated earlier; as to unvaccinated persons--it created a favourable immunological preparedness for revaccination, permitting to do without any antitetanus serum in case of trauma.