ALBERT

Notes: Abstract For certain environments, the Darwinian model allows unique prediction of a function that any surviving system adapted to such an environment has to perform. This is the case for those environments that determine a “survival functional” of position in space-time of known shape. Purely temporal survival functionals can be distinguished from spatial and mixed ones. In each case, there exists an optimum path in combined physical and (reduced) metabolic space. Dependent on the admissible error, approximate solutions of different complexity are sufficient. All solutions possess an afferent, a central, and an efferent part. Within this general frame, specific, “probably simplest”, solutions are proposed for adaptive chemotaxis, insect locomotion, lower vertebrates locomotion, higher vertebrates locomotion, chronobiological systems, and immune systems, respectively—or rather, for the underlying functionals.

Notes: Abstract Mathematical models afford a procedure of unifying concepts and hypotheses by expressing quantitative relationships between observables. The model presented indicates the roles of both insulin and glucagon as regulators of blood glucose, albeit in different ranges of the blood glucose concentrations. Insulin secretion is induced during hyperglycemia, while glucagon secretion results during hypoglycemia. These are demonstrated by simulations of a mathematical model conformed to data from the oral glucose tolerance test and the insulin infusion test in normal control subjects and stable and unstable diabetic patients. The model studies suggest the parameters could prove of value in quantifying the diabetic condition by indicating the degree of instability.

Notes: Abstract A model for the dynamics of a single-species population whose birth rate depends on densities of previous generations is introduced. A difference equation formulation is proposed and the solutions classified for the various parameter values. Data from an experimental population of mice growing in limited space is cited and compared with the model predictions.

Notes: Abstract All soft tissues are modeled as either one-dimensionalstrings, two-dimensionalmembranes, or three-dimensionalsolids. Attention is restricted to tissues in which one of the principal stress components is large and positive in comparison with the other negligible components. Results indicate the following: (1) If a deformed string isconstrained to lie on a surface and is free of tangential pressure, the tension is carried by rays which are geodesics of the surface. If a string or membrane isfree to deform in space without normal pressure, the tension rays are straight lines. If a membrane deforms without tangential surface loads, the tension rays are always geodesics on the deformed surface. If a solid deforms without body forces, the tension rays are straight lines. (2) The stress in a string is a constant if the string is free of tangential pressure and has constant cross-sectional area. The stress in flat tension fields free of tangential surface loads decays inversely with distance along a tension ray from the edge of regression. The stress in a spherically symmetric tension field free of body forces decays inversely with the square of the distance from the center of the sphere. (3) Stress singularities can occur in soft tissues, such as at the corners of a closed rectangular hole in a flat membrane strip. (4) The tension rays in the torsion of soft annular membranes are more steeply inclined from the radial direction than the tension rays for hard metals equally displaced.

Notes: Abstract Non-steady-state equations for kidney models are stated. General conservation relations for these equations are derived. Transient equations for the central core model of the renal medulla are developed. Solution of the equations by Laplace transform methods for time invariant volume flows is discussed. The general theory of solving models with time dependent flows by finite difference methods is developed.

Notes: Abstract The behavior of large systems of randomly-interacting variables is examined using an intentionally simplified model. The stable positive solutions are found to exhibit to a significant degree some well-known properties of ecological systems. This resemblance (including for example the predominance of “predator-prey” interactions) is all the more striking in view of the lack of biological “data” at the input end. The findings suggest it advisable to distinguish two kinds of properties in ecosystems. One kind would depend on specifically biological mechanisms; the other would characterize a wide class of persistent systems, and arise from the need for a dynamic balance between positive and negative feedback.

Notes: Abstract For the tumor model of Skipper and Zubrod, which has been analyzed previously for the theoretical FLM function and the effect of chemotherapy against tumors of known or assumed kinetic characteristics, the theoretical continuous labeling (CL) function is derived by considering an equivalent tumor (in terms of unlabeled cell populations) in which the density function of phase duration of cells inS-phasef 2(a 2)=δ(a 2−∞) and the loss functionL 2(t)=0. This mathematical concept of blocking is applied to the analysis of synchronization in tumor growth and blocking effects in cancer chemotherapy. These effects of chemical agents on the cell cycle progression are being incorporated into a previously written computer simulation program for cancer chemotherapy. Whereas, a program is written and used to simulate the CL functions for L1210 leukemia, and primary and metastatic Lewis lung carcinoma.

Notes: Abstract Global stability is established in a class of prey-predator models. This includes a prey-predator model in which the predator has Type 2 functional response and no intraspecific interactions. Two simple examples demonstrate that Kolmogoroff’s theorem does not apply to some members of this class of models.

Notes: Abstract The skeletal muscle is regarded as a periodically deformed plate. An equation of energy for the biological tissue in the system is used in the Lagrange variables. With the heat exchange through the above tissues to the exterior media and also with account of some relations between the physiological factors the approximate analytical solution for this equation is obtained and compared with the physiological data.

Notes: Abstract One of Bobisud's (1976) models for the evolution, of cannibalism is discussed. His analysis is criticised for not being based on the principle of individual selection. Assuming the operation of that principle, we show by simulating his model that cannibals may establish themselves in a noncannibal population. This will happen both in cases where Bobisud concluded cannibalism to be optimal and in cases where he concluded cannibalism not to be optimal.

Notes: Abstract The D'Arcy Thompson concept of biological transformations is developed in a form analogous to such physical concepts as the Law of Corresponding States in thermodynamics, and the Principles of Similitude found in engineering. We find that such concepts depend on a distinction between fundamental and derived quantities, in which the values assigned to the fundamental quantities set the natural scales for the derived ones. Among other things, we see that critical phenomena, such as phase transitions, arise as an immediate consequence of this distinction. In a biological context, we explore the implications of Thompson's hypothesis that closely related organisms are phenotypically similar, assuming that the organisms we see are the result of selection processes operating on phenotypes.

Notes: Abstract If information is coded in the combination of activities of many neurons operating in parallel, then information present in a network can be defined by the correlation of present network activity with the activity which had been elicited by a stimulus in the past; a high correlation indicates the presence of the previously encoded stimulus. Information is distributed in the network because coding is dependent upon the activities of all cells. A model based on Hartline-Ratliff lateral inhibition with a time delay shows that lateral inhibition can distribute information across a parallel network, reduce output noise, and also briefly store information. With no changes in model parameters, and the use of a correlation measure for recognition, the model can stimulate psychophysical results in eleven variations of the metacontrast masking paradigm.

Notes: Abstract A theory is derived to calculate the regional and total deposition of aerosol particles in the nasal passages during inhalation. The particle size studied range from 0.2 to 10.0 μm diameter. The deposition is calculated in five regions; (I) the region filled with nasal hair, (II) the nasal valve, (III) the expansion region, (IV) the turbinate region and (V) the posterior bend. Equations are derived to determine the deposition caused by direct impaction on the nasal hairs and bends of the passages. The calculations show the deposition due to direct impaction does not account for the amount or location of deposited particles measured in experiments. Secondary flows have been speculated to exist in the expansion region after the nasal valve and an equation is derived to estimate the deposition caused by the secondary flows. The calculated deposition, due to direct impaction and secondary flows, shows general agreement with the experiment as to the predicted amount and location of deposited particles.

Notes: Abstract The paper reviews a series of models for circadian clocks and discusses their conclusions and predictions. Attention is focused on Pittendrigh's empirical model, two mathematical models by the author and Winfree's work.

Notes: Abstract From a model of facilitated ionic transport across axonal membranes proposed by McIlroy (1975), the equipotentials and electric field distributions in the vicinity of a potassium conducting pore and of a sodium conducting pore are computed and presented as two-dimensional mappings. The model is then extended to include the effect of impurity ions in the conducting pores viz. of potassium ions in a sodium pore and of sodium ions in a potassium pore. The ionic selectivities and permeabilities of the transported species are discussed in relation to the extended model. Bounds are deduced for the ionic selectivity coefficients for both the sodium and potassium current-carrying systems in squid giant axons and the electric-field distributions in the vicinities of the pores are computed for the extended model and compared with the impurity-free fields first calculated. Finally the permeability coefficients defined in terms of the extended model are shown to reconcile the results of attempts to measure permeability by means of radioactive tracer techniques, with the classical description of the resting nerve.

Notes: Abstract The partial differential equations describing transcapillary exchange and subsequent removal of solutis from an idealized liver sinusoid are amenable to solution by similarity analysis. The power and utility of this technique, which is not widely appreciated as a method for solving biological models, is illustrated here for a system whose Laplace transforms is difficult to invert.

Notes: Abstract The phenomenological theory for the chemotaxis and consumption of oxygen by motile aerobic bacteria is shown to yield a remarkably simple one-dimensional steady-state solution for a congregation of bacteria close to the surface of an oxygen-depleted aqueous medium.

Notes: Abstract In this paper biological compartmental models are considered which take into account the intrinsic randomness of the transport rate parameters and their possible variability in time. An identification procedure is presented for the estimation of the stochastic processes representing the transport rate parameters of a compartmental model from a noisy input-output experiment. The problem is formulated in terms of nonlinear filtering. A simple model is discussed for the case in which the transport rate parameters are independent of each other. The possibility of testing possible important features of the behavior of the transport rate parameters is also evidenced.

Notes: Abstract For any essentially nonlinear system of reaction-diffusion equations of the generic form ∂ci/∂t=Di∇2ci+Qi(c,x,t) supplemented with Robin type boundary conditions over the surface of a closed bounded three-dimensional region, it is demonstrated that all solutions for the concentration distributionn-tuple function c=(c 1(x,t),...,c n (x,t)) satisfy a differential variational condition. Approximate solutions to the reaction-diffusion intial-value boundary-value problem are obtainable by employing this variational condition in conjunction with a Galerkin-Ritz procedure. It is shown that the dynamical evolution from a prescribed initial concentrationn-tuple function to a final steady-state solution can be determined to desired accuracy by such an approximation method. The variational condition also admits a systematic Galerkin-Ritz procedure for obtaining approximate solutions to the multi-equation elliptic boundary-value problem for steady-state distributions c=−c(x). Other systems of phenomenological (non-Lagrangian) field equations can be treated by Galerkin-Ritz procedures based on analogues of the differential variational condition presented here. The method is applied to derive approximate nonconstant steady-state solutions for ann-species symbiosis model.

Notes: Abstract The geometrical nature of the Elementary catastrophes (Thom, 1969) is reviewed. Histories of the movement of catastrophe manifolds and bifurcation sets are presented for some of the space-equivalent unfoldings described by Wassermann (1975). These unfoldings provide descriptions of the variation with time of the stability of stationary states of associated potential energy functions. Identification of these stationary energy states with stationary states of a system therefore provides a description of its behavior with time. Qualitative descriptions of this type are particularly useful when the complexity of a system prevents a detailed quantitative description. Histories of bifurcation set movements suggest different types of system behavior at different space-like coordinates. This type of theory may be a useful model for the processes leading to differentiation of cells and to emergence of adult forms of a biological organism.

Notes: Abstract Three conjectures are given which predict the existence of unique stable limit cycle oscillations in a class of piecewise linear (PL) differential equations. The equations are appropriate to model biological or other complex systems in which there are switchlike interactions between the elements of the network. Methods are presented which can be used to develop mathematical models which are conjectured to display stable limit cycle oscillations, from qualitative experimental information about relative phases of activity in the dynamical systems. Several illustrative numerical examples are given, and one experimental example from neurobiology is discussed.

Notes: Abstract The formulation and results of the Kalman State Regulator Problem are applied to a mathematical model of the arterial system of a dog to obtain an optimal control for blood pressure. The criterion for optimality is minimum energy per cycle.

Notes: Abstract A mathematical model is developed in state variable form suitable for the study of the control of blood pressure and flow in the mammalian cardiovascular system. The applicability of the model to steady state, both mean and pulsatile, and transient phenomena is demonstrated by the agreement of the results with experimental data. This model was developed to study the neural and renal-endocrine-electrolyte control of cardiovascular functions.

Notes: Abstract As a contribution to the discussion of oscillatory models for interacting species it is shown that two-species Volterra models can never have limit cycles, and a complete enumeration is given of conditions which the parameters of these models must satisfy in order that a part of the phase space be filled with a family of closed curves; sketches of phase portraits are also given. These results complement and correct older results by Bautin and by Coppel on quadratic differential systems. The paper opens with a brief discussion of some more practical aspects of the ecological application of oscillatory models.

Notes: Abstract The purpose of this paper is to present a method for the determination of a solution for a coupled system of first order initial boundary-value problems arising from some biological systems. The physical problem is to determine the suspended and the superficial molecular concentrations of a traced substance passing through an organ containing a tangle of vessels, such as the kidney-ureter system. The approach to the problem is by successive approximation which leads to a recursion formula for the determination of the solution as well as error estimates for the approximations. The recursion formula involves only direct integration which indicates a promising possibility in obtaining numerical results by using a computer. In addition to the determination of a solution, some qualitative analysis of the solution is given. This includes the existence of a unique solution, the continuous dependency of the solution on the data, and the stability problem of a steady-state solution.

Notes: Abstract In Part I, the general solution of the heat transport equation was given for a medium of constant thermal properties, containing a general convection fieldv(r,t). Starting from this general solution, an average or “macroscopic” temperature distribution is calculated in this paper, since in most physiological problems only an average or “macroscopic” temperature is accessible to the measurement. It is shown that the averaged temperature distribution is influenced alone by the order of the local symmetries of the convection field. These local symmetries can be deduced from anatomical data on the vascular architecture. In order to perform the averaging process, a detailed discussion, and an estimate of the correlation between the microscopic temperature variation and the convection field is carried out. Hereby, great emphasis is put on the experimental consequences of these results. As an illustrative example, the calculation of the macroscopic temperature distribution in a medium traversed by parallel capillaries is outlined.

Notes: Abstract The study of current flow fields in biologicaltissue requires finding the potential field from dipole sources such that the normal gradient vanishes at the exterior surface. A convenient way to determine the dipole field is by taking the gradient of the potential field set up by a point source. However, the point source problem is ill-posed when the normal gradient is required to vanish at the outer surface. In the paper the nature of this problem is discussed and several methods for overcoming the difficulty are presented.

Notes: Abstract An analysis of the hydrodynamics of aqueous flow in the posterior chamber of the anterior segment of the eye is presented. The viscid, incompressible description of fluid dynamics in a spherical geometry is utilized to reduce the problem to a biharmonic-type equation using a “Stokes Stream Function”. Analogous to Poiseuille flow in a cylindrical pipe, velocity profiles are deduced and an Ohms Law relationship between pressure and flow is derived in terms of the geometry of the assumed model. This result is then incorporated into a synthesized electric circuit analog of flow between ciliary artery and episcleral vein. Applications to open angle and pupilary block glaucoma are discussed.

Notes: Abstract With the assumption of dipole interaction with the membrane matrix, the dipole barrier under an applied field shows a minimum in its time transient. Kinetic equations governing the migration of ions are presented. Na+ activation, Na+ inactivation and K+ delay are all part of the same mechanism in this model with no other separate assumptions needed. Voltage Clamp equation and action potential equation are presented.

Notes: Abstract A metabolic model for copper is derived and presented in the context of the International Commission on Radiological Protection (ICRP) dosimetry models for the lungs and gastrointestinal tract.

Notes: Abstract The analytical conditions by which a Volterra's general system describingn interacting species can be put in the “conservative” form have been examined. The cases forn=2, 3, 4 have been analyzed in detail and a general condition for any value ofn is deduced. The analytical and biological constraints following by this approach are compared to the conclusions drawn by Leigh on the ground of purely biological considerations.

Notes: Abstract General formulation of stochastic single- and multi-compartment reversible systems with time-dependent transitions is made. The correspondence between the stochastic mean and the deterministic value is established in case of time-dependence and it is shown how the consequence of this can be utilized to compute the distribution and the moments of each individual compartment of the system. A two-compartment reversible system previously proposed by Cardenas and Matis (1975a) is analyzed on the basis of the theory.

Notes: Abstract Optimal control theory is applied to the problem of controlling pests by biological and chemical means simultaneously. The net birth rate of the pests is controlled chemically while at the same time predators are allowed to operate. Several numerical examples are included.

Notes: Abstract Transient solutions are developed for the buildup of a concentration gradient in the single loop solute cycling model of the renal medulla. The “pump” from ascending limb to descending limb is considered in both unsaturated and completely saturated modes of operation. Both analytic solutions and semianalytic solutions obtained from inverting Laplace transforms are considered. The classic representation of concentration buildup by the multiplication process is compared with calculated profiles. The “single effect” is found to vary both in time and space.

Notes: Abstract In this study the possibility of applying the asymptotic method of Krylov-Bogoliubov-Mitropolskii to problems of population dynamics is shown. Especially a general Volterra-Gause-Witt type model for prey-predator interaction is investigated. A discussion on the results obtained is given for the general model and for a particular case as well.

Notes: Abstract The analytical exploration of hierarchical structures is a central problem in modern biology. In many ways, the most basic tenet of any theory of any biological system is that its behavior lies within the laws of thermodynamics. Thus an investigation into the hierarchical structure of field thermodynamics is in effect an investigation into the underlying structures common to all biological systems. In field thermodynamics, the dynamics is prescribed at the hierarchical level of description concerned with the motions of classes of the various molecular species flowing in the system. Of crucial importance are scale factors which convert potentials into potential energies per mole of the various molecular species. On the other hand, the overall behavior of the system is presented at a higher hierarchical level of description in terms of systemic properties such as charge density or entropy density. Three questions are investigated: (1) how is the transition from the specific to the systemic level of description effected, (2) given the scale factors at the specific level how does one find those at the systemic level, and (3) what relationship can one, find between the scale factors at the two levels of description? Answering these questions necessitates an examination of the nature of the forces at the two levels of the hierarchy of descriptions.

Notes: Abstract The identification of a linear compartment model, which may describe a chemical or biological process, is a difficult task, since the available data is generally limited. In this paper we propose a method for determining the state transition matrix by minimizing a given quadratic criterion. To solve the resulting matrix equation, an assumption has to be made which constitutes a necessary condition for the identifiability of the model. Moreover when this assumption is satisfied, it is shown that the knowledge of one line or one column of the transition matrix is sufficient to define it completely.

Notes: Abstract The two-element muscle model considered consists of a contractile element defined by a hyperbolic force-velocity relation connected in series with an “exponential spring”. Differential equations for the isometrically developed force during a tetanic contraction and the corresponding contractile element shortening velocity are derived and their stability is investigated. Analytical solutions to both equations are obtained. Two numerical examples are given, the second chosen to illustrate pressure-induced hypertrophy of a cardiac muscle.

Notes: Abstract We study a two-type, age-dependent branching process in which the branching probabilities of one of the types may vary with time. Specifically this modification of the Bellman-Harris process starts with a Type I particle which may either die or change to a Type II particle depending upon a time varying probability. A Type II particle may either die or reproduce with fixed probabilities but may not return to a particle of Type I. In this way the process models the lag phenomenon observed in microbe growth subsequent to transfer to a new culture medium while the organism is adapting to its new environment. We show that if the mean reproduction rate of Type II particles exceeds 1, then the population size grows exponentially. Further the extinction probability for this process is related to that of the Bellman-Harris process. Finally the governing equations are solved for several choices of the growth parameters and the solutions are graphically displayed showing that a wide variety of behavior can be modeled by this process.

Notes: Abstract This paper studies the effect of harvesting a fraction of a population where the population growth is modelled by a linear age-dependent model, the Von Foerster equation. Two harvesting strategies are considered: the first is where a fraction of the population greater than agec is removed, and the second is where a fraction of the population of age greater thanc but less thanc+n is removed. In the case where the death rate and fertility rate are time independent, the effect of harvesting on the stable age distribution is examined.

Notes: Abstract The general means are set forth by which, in a highly speciated Volterra eco-system, the bifurcation of a species into two in a competitive-exclusion configuration, provides a description of odd as well as even systems. The the Gibbs ensemble theory earlier developed is extended to grand ensembles in which the number of ecotypical species in genera-like clusters is allowed to be variable. The probability law for the sizes of clusters is deduced, and shown very closely to imply independent Poisson statistics for the cluster sizes, in answer to a fundamental issue of bioevolution. The role of the eco-analogs of Gibbs’ chemical potentials is brought forth, with a suggestion of how to describe cluster-to-cluster eco-genetic flows, and therewith a definite relationship between the degrees of speciation of genetically linked clusters on the one hand, and amplitudes of population fluctuations of member species within the clusters on the other hand.

Notes: Abstract Solutions of the Poisson-Boltzmann equation yield potential profiles and equilibrium distributions of ions on either side of a spherical shell membrane across which there exists a separation of ionic charges. For the special case in which the membrane is permeable to only one ion the total charge separation is analyzed in terms of the potential difference given by the Nernst equation. Potential profiles and ionic charge distributions are also given for situations involving a uniform distribution of fixed charges within the membrane.

Notes: Abstract The recently proved classification theorem of René Thom has led to the development of the new science of Catastrophe Theory. This theory has been widely held to be particularly relevant in biological applications. The present paper presents a simplified proof of Thom’s Theorem and assesses its importance in biology.

Notes: Abstract A mathematical model describes the mechanical behaviour of ventricular aneurysms assuming a spherical geometry for the left ventricle. Employing pressure-volume data obtained from normal dog hearts 1–2 hours after infarction, conditions are obtained on infarct thickness and angle of damage for ventricular rupture to occur. The results indicate that rupture is more likely to occur in the early period following infarction and that the dominant factor is the per cent thickness of the infarct.

Notes: Abstract A deterministic investigation of a linear differential equation system which describes predator vs prey behavior as a function of equilibrium densities and reproductive rates is given. A more realistic structure of this model in a stochastic framework is presented. The reproductive rates and initial population sizes are considered to be random variables and their probabilistic behavior characterized by various joint probability distributions. The deterministic behaviors of the prey and predator species as functions of time are compared with the mean behaviors in the stochastic model.

Notes: Abstract The effects of ventricular geometry, muscle mass, muscle elasticity and external pressures on the pressure-volume and muscle stiffness-stress relations have been quantitated on the basis of a theoretical model. Data taken from patients before and after interventions with nitroprusside and angiotensin were applied to the model in order to explain the possible causes for the marked shifts in the pressure-volume relations. The results indicate that (a) ventricular geometry does not markedly alter the pressure-volume and stiffness-stress relations unless there is a drastic change from a spherical shape to an ellipsoidal shape orvice versa, (b) increases in muscle mass and muscle elasticity of the order of 30% result in significant alterations in the P-V relations but are not the cause for the parallel shifts unless accompanied by substantial external pressures, (c) the parallel shifts in the pressure-volume relations can be accounted for entirely by the presence of external pressures without changes in muscle mass or muscle elasticity. Thus manipulation of right ventricular pressures or pericardial pressures by drug interventions may be useful in the treatment of left heart disease and the presence of such pressures must be considered in the analysis of ventricular function curves.

Notes: Abstract This paper summarizes in a nonmathematical way the major properties of coupled oscillators which relate to circadian rhythms. For certain values of the coupling strength it is far easier to maintain synchrony than to achieve it among the various interacting units. This property not only simulates the free run period lability but also the effects of critical pulses.

Notes: Abstract A deterministic model for a multi-agent disease epidemic with asymptomatic attacks is proposed and investigated. The limitations inherent in the assumptions of the model are discussed in connection with specific agents of disease. The mathematical treatment of the model is separated into analyses of the equilibrium situation and the transient behavior of the disease outbreak. Explicit formulas are derived for the number of susceptibles in the population as well as for the numbers of each type of infective—those with and without symptoms. These theoretical results are followed by a discussion of the practical considerations which must be taken into account to obtain useful information from the model.

Notes: Abstract The recently observed enhancement, by laser irradiation, of the specific activity of the enzyme chymotrypsin (which hydrolyses Benzoyl-L-tyrosine-ethyl ester) at low enzyme concentration is considered. The enhancement of the reaction rate is attributed to a coherently excited state of the enzyme molecule (activated through Raman scattering of the laser light) following a prediction due to Fröhlich. The model is described, the kinetics of the process is framed and the observed enzyme-concentration dependence of the specific activity is reproduced. Predictions of the model are delineated to urge verification of the main contentions through further experimentation.

Notes: Abstract The deposition of aerosol particles in the human lung airways is due to two distinct mechanisms. One is by direct deposition resulting from diffusion, sedimentation and impaction as the aerosol moves in and out of the lung. The other is an indirect mechanism by which particles are transported mechanically from the tidal air to the residential air and eventually captured by the airways due to intrinsic particle motion. This last mechanism is not well understood at present. Using a trumpet airway model constructed from Weibel's data, a two-component theory is developed. In this theory, the particle concentrations in the airways and the alveoli at a given airway depth are considered to be quantitatively different. This difference in concentrations will cause a net mixing between the tidal and residential aerosol as the aerosol is breathed in and out. A distribution parameter is then introduced to account for the distribution of ventilation. The effect of intrinsic particle motion on the aerosol mixing is also included. From this theory, total and regional deposition in the lung at the steady mouth breathing without pause is calculated for several different respiratory cycles. The results agree reasonably well with the experimental data.

Notes: Abstract The Abel type differential equation governing the kinetics of the enzyme reactions is derived. Approximate solutions of this equation corresponding to the transient phase of the reaction, before a steady state is reached, are considered. It is shown that in several cases it is possible to obtain explicit, approximate solutions to the transient phase.

Notes: Abstract Maximum and minimum principles for the steady-state finite cable model of nerve membranes are derived from the canonical theory of complementary variational principles. An accurate variational solution is obtained in an illustrative calculation.

Notes: Abstract The paper presents a qualitative analysis of the following systems ofn differential equations: $$\dot x_i = x_i x_j - x_i \sum\nolimits_r^n { = 1} x_r x_s {\mathbf{ }}(j = i - 1 + n\delta _{i1} {\mathbf{ }}and{\mathbf{ }}s = r - 1 + n\delta _{r1} )$$ , which show cyclic symmetry. These dynamical systems are of particular interest in the theory of selforganization and biological evolution as well as for application to other fields.

Notes: Abstract Bifurcation theoretical and numerical analyses of one of Turing's models are performed. It is shown that at the first instability point of the homogeneous state the bifurcating branches aresubcritical, and thus emerge as unstable solutions. This, together with the presence of concentration-independent sink terms is responsible for the solutions becoming negative ast→∞. It is pointed out that this deficiency is an accident related to the choice of the model, and that the general idea of symmetry-breaking is perfectly compatible with the generation of regular morphogenetic patterns.

Notes: Abstract Several models have been proposed to underststand the patterns of nerve impulses produced by periodic stimuli. This paper shows that for a very large class of such models there exists a pattern of phases that repeats periodically after a finite number of pulses; the actual pulses produced by the model depend on its initial condition, but in all cases they either follow such a pattern or approach it asymptotically.

Notes: Abstract The global force-flow equations of nonequilibrium thermodynamics are obtained by solving the local equations of motion for a system ofn-components (n−1 solutes plus water) passing through a membrane. When viscous forces and position dependent membranepermeating species frictional interactions are considered, it becomes more difficult to obtain the result because even the stationary state problem becomes one of solving a second order linear ordinary differential equation for the barycentric velocity in a space divided inton+1 regions. Using the continuity of the boundary velocities and their gradients as well as the usual boundary conditions for the hydrodynamic problem, a set of 2n+1 linear equations in the intergration constants can be obtained and a closed form solution is possible. The resultant global description of the system does not obey Onsager reciprocity. What is more, the interpretation of global phenomenological coefficients in terms of local interactions in any simple way is next to impossible. This makes the hope of a molecular level interpretation of phenomenological membrane transport coefficients very slim. The relevance of this finding to the validity of reductionist approaches to biological transport is discussed.

Notes: Abstract A mathematical model of transmural transport of oxygen to a metabolizing retina is presented based on the equations of fluid dynamics. The equations of oxygen transfer are derived and then solved subject to the condition that the capillaries begin to transport oxygen at an initial time. The resulting transient analysis gives us insight into how diffusive and filtrative processes lead to the oxygen distributions both inside and outside capillaries. On the other hand, the steady state solution allows us to predict the cutoff intraocular pressure above which no oxygen is transferred to retinal tissue. It also gives quantitative relationships which allow us to postulate how intracapillary hypertension counterbalances elevated intraocular pressures and how low pressure glaucoma may arise from ineffective diffusive and filtrative processes of oxygen transport.

Notes: Abstract An analysis of the interactions among asymptotically stable dynamical systems is formulated by making use of the dynamical system theory. Some results coming from previous mathematical analyses have been slightly modified to take into account some typical biological constraints as the boundedness properties of the solutions. In particular it has been shown that when the “coupling” among the subsystems is “loose” enough (in a sense that has to be made mathematically precise) the asymptotic behaviour of a complex system is the same of that of its individual components. The mathematical theory has been used to analyze two systems of biological significance: the coupling among chemical reactions and the stability properties of a 4-dimensional system describing the kinetics of a chemical transmitter.

Notes: Abstract This note supplies missing details and corrects some mathematical errors in the recent significant paper by Auchmuty and Nicolis (1975).

Notes: Zusammenfassung Es wird über Regelwidrigkeiten am Schädel eines 12 Monate alten Rickenkitzes berichtet. Die durch zwei Fotos belegten Anomalien sind folgende: 1. Verkürzung der Nasenbeine; 2. Hypertrophie der Stirnwülste; 3. Deformierung des Unterkieferastes, insbesondere Verbiegung des Muskelfortsatzes.

Notes: Zusammenfassung Unter einem „Alleinfutter” ist eine Futtermischung zu verstehen, in der alle für die Erhaltung und Leistung erforderlichen Nähr-, Mineral- und Wirkstoffe mit einem entsprechenden Energieanteil enthalten sind. Speziell für die Fütterung des wiederkäuenden Schalenwildes bildet eine solche Äsung gegenüber einem üblichen Kraftfutter und sonstigen Futterstoffen, wie z. B. Getreide, Rüben, Heu oder Stroh große ernährungsphysiologische Vorteile, da alle vorgesehenen Inhaltstoffe gleichzeitig vom Wild aufgenommen werden. Auf diese Weise kann eine einseitige Futteraufnahme verhindert werden, die bei Wiederkäuern leicht zu Schädigungen der Pansenflora führt und damit wesentliche Ursache für das Auftreten von Erkrankungen ist. Besonders bewährt haben sich zur Verfütterung an wiederkäuendes Schalenwild Silagen. In nunmehr über 8 Jahre durchgeführten Versuchen in 3 Forstverwaltungen der nordwestlichen Eifel ist eine Alleinfutter-Silage hergestellt und erprobt worden. Als Grundkomponenten dienen Apfeltrester, Zuckerrübenblatt, Mineral- und Wirkstoffe sowie Heu oder Stroh. Die Herstellung erfolgt mit Hilfe eines Gebläsehäckslers. Ein solch strukturiertes Futter ist wiederkäuergercht, wird von den Tieren gerne aufgenommen und deckt bei ad libitum-Aufnahme den Erhaltungsbedarf. Die Kosten betragen etwa 90–100 DM/1000 kg. Um die täglichen Ausbringungskosten zu vermindern, sind bisher 29 Selbstfütterungen mit gutem Erfolg eingesetzt worden, durch die dem Wild ständige Äsung zur Verfügung steht und somit Fütterungsfehler dieser Art entfallen

Notes: Zusammenfassung Zur Diskussion gestellt wird der Untersuchungsbefund aus dem Kreisveterinäramt Kleve, der sich mit Gänseverlusten am Niederrhein in Nordrhein-Westfalen in Zusammenhang mit einem Wintergewitter befaßt. Erörtert werden als mögliche Ursachen in der vorliegenden Mitteilung Blitzschlag, Hagelschlag, Zusammenstoß mit Flugzeugen (Vogelschlag) und die Auswirkung von Druckunterschieden bei sturzflugartigem Verlassen großer Flughöhen.

Notes: Zusammenfassung Arzneimittel werden meistens peroral, d. h. über den Magen-Darm-Kanal, zugeführt. Damit besteht die Möglichkeit einer Interaktion mit Nahrungsinhaltsstoffen, die aber dann bedeutsam sein dürfte, wenn essentielle Nahrungsfaktoren wie z. B. Vitamine betroffen sind. Für die Vitamine können sich dann folgende Auswirkungen ergeben: eine vorzeitige Zerstörung bzw. Inaktivierung, eine gehemmte Resorption aus dem Magen-Darm-Kanal oder eine quantitativ und qualitativ veränderte Metabolisierung. Anhand von Beispielen werden derartige Auswirkungen von Arzneimitteln auf wasserlösliche und fettlösliche Vitamine aufgezeigt.

Notes: Zusammenfassung Schimmelpilzkulturen werden bei der Herstellung von Weißschimmel— und Blauschimmelkäse verwendet. Es wird über den gegenwärtigen Stand der Kenntnisse zur Frage von Mykotoxinbildnern in Schimmelpilzkulturen der Käsefabrikation berichtet. Verschiedentlich wurde ausPenicillium roqueforti-Stämmen, die auf speziellen Medien bebrütet wurden, das PR-Toxin isoliert, auch aus P. roqueforti-Kulturen, die zur Käseherstellung verwendet werden. Doch sind die Bedingungen der Käsereifung für eine Produktion dieses Toxins nicht geeignet. Weitere Stoffwechselprodukte von P. roqueforti wie Roquefortin und Isofumigaclavin konnten in Käse aufgefunden werden, doch ist über deren toxische Wirkung wenig bekannt. Kanzerogen wirkende Mykotoxine konnten in Schimmelkäsen nicht gefunden werden, außer Aflatoxin M1, das jedoch aus der kontaminierten Milch stammen dürfte. Das Auftreten von Tumoren nach Verfütterung einer Reinkultur vonP. camemberti var. candidum ließ auf eine Mykotoxinwirkung schließen. Doch haben weitere Tierversuche mit verschiedenen, bei der Käsefabrikation verwendeten Schimmelpilzstämmen diesen Befund nicht bestätigt. Es läßt sich aufgrund der gesichteten Literatur sagen, daß der Einsatz von Schimmelpilzkulturen in der Käsefabrikation kein Risiko für den Menschen darstellt, also toxikologisch unbedenklich ist.

Notes: Zusammenfassung Nach 24stündiger präoperativer Infusionsperiode werden von der infundierten Menge 0,37% Glukose, 0,05% Fruktose und 1,28% Xylit im 24-h-Urin ausgeschieden. Postoperativ erweist sich Fruktose vor Xylit und Glukose als der am besten verwertete Energieträger. Als Zeichen einer ungestörten hepatischen Lipoproteinsynthese steigen die Triglyzeride bis zum 5. postoperativen Tag an. Unter der parenteralen Ernährung und durch den zusätzlichen operativen Eingriff erfolgt ein starker Cholesterinabfall von 192,3 auf 128,5 g/100 ml am 1. postoperativen Tag. Durch die Infusionslösungen steigt die Insulinkonzentration von 23,2 auf 46,3 U/1 am Operationstag an. Postoperativ werden erhöhte Insulinwerte gemessen. Die Harnsäurekonzentration fällt bis zum unteren Normbereich ab. Am Operationstag besteht eine positive N-Bilanz von 3,5 g/24 h. Die leicht negative Bilanz von −1,15 g/24 h am 1. postoperativen Tag geht bis zum 4. postoperativen Tag auf −0,61 g/24 h zurück. Die Veränderungen der gemessenen Enzyme LDH, GOT und AP bewegen sich im Normbereich. Die postoperativen Veränderungen sind auf den operativen Eingriff zurückzuführen. Ohne entsprechende Enzymveränderungen erfolgt bei 5 Patienten ein Anstieg der Bilirubinkonzentration auf 1,25 mg/100 ml. Um zu große endogene Phosphatverluste bei längerfristiger parenteraler Ernährung zu vermeiden, ist es notwendig, eine Bilanz aufzustellen.

Notes: Zusammenfassung Beschrieben wird eine neue enzymatische Methode zur gleichzeitigen Radioaktivitätsbestimmung von 1-14C-Glukose und 1-14C-Fruktose. Prinzip ist die Umwandlung von 1-14C-Fruktose in 1-14C-Glukose mit Phosphoglukoseisomerase (EC 5.3.1.9) und anschließende Umwandlung der gebildeten 1-14C-Glukose in Ribulose-5-phosphat und14CO2. Das Verfahren ist spezifisch, gut reproduzierbar und ergibt Wiederfindungsraten in wäßrigen und biologischen Flüssigkeiten von 97 % bis zu Glukose- und Fruktose-Konzentrationen von 11 mmol/l.

Notes: Summary In maturity onset diabetes the blood levels of total blood keto acids in terms of pyruvic, serum citric, calcium are significantly higher than in normal adults, while there is a decrease in reduced-blood glutathione, serum zinc, potassium and sodium levels. There were no significant differences between diabetes and normal adults in the serum levels of copper, ceruloplasmin oxidase activity, iron and magnesium.

Notes: Abstract Field experiments were designed to evaluate the role of predators in the Wadden Sea, small predators like shore crabs, shrimps and gobies, and large ones like flatfish and birds. Exclosures, maintained in aCorophium volutator bed, an eelgrass bed, in a sandy and a muddy flat, protected the infauna from such epibenthic predation. The resulting changes in the macrofauna were recorded and compared with an unaffected control area. In sandy and muddy flats of the lower intertidal zone, cages (mesh size≤5 mm) altered abundance and composition of the infauna almost entirely. Nearly all species achieved higher population densities than in the control area, and in addition, the number of species increased as well. In the the scarcely populated mud flat a dense suspension-feeder assemblage emerged, associated with numerous tube-building polychaetes. The sand flat, normally dominated by deposit feeders, also became occupied by a dense suspension-feeder assemblage, mainly cockles. In contrast, narrowly meshed cages had only little effect in the beds of eelgrass and ofCorophium volutator. Both are positioned in the upper intertidal zone. Although a number of species still responded with significant increases in abundance, many remained indifferent or even tended to be less abundant within cages. Cages provided with a 20-mm mesh nylon net, excluding only birds, flatfish and the biggest crabs, increased significantly the survival of large-sized infaunal members. This was only apparent in the upper intertidal zone. It was concluded, that small sized epibenthic predators are the major determinants of the dynamic species abundance pattern of the lower intertidal flats. In the eelgrass bed, the meshwork of rootlets constitutes an important spatial refuge from these predators. The complex habitat structure causes a diversified faunal assemblage. TheCorophium bed in the uppermost intertidal zone is less accessable to predators like crabs, shrimp and gobies. The monotonous appearance of this faunal assemblage is assumed to be the outcome of competitive exclusion and of occasional harsh physical conditions.

Notes: Abstract The gills of several polychaete species belonging to 9 families were studied by scanning and transmission electron microscopy. The surface epithelium is covered by a thin cuticle which is invaded by microvilli penetrating the epicuticle in certain species. Some epithelial cells bear cilia, others are mucus-producing cells. The ciliary cells may be arranged in rows and maintain a constant flow of water over the gills. The distance between external water and blood stream differs considerably according to the species investigated. InMalacoceros the gills are characterized by closed afferent and efferent subepithelial vessels, which correspond to tubular invaginations of the coelomic wall. These vessels are lined by the basement lamina of the coelothelial cells, which are of the epitheliomuscular type. The vessels are open in the gills of other polychaetes and release the blood stream into a system of spaces immediately below the epidermis (e.g. in the branchial lamellae ofPectinaria andTerebellides). In several species the blood comes into very intimate contact with the cuticle (e.g. in the gill filaments ofDendronereides), but also in these animals both are separated by a very small epidermal layer.

Notes: Abstract The method used consists of adding highly radioactive material (40 μCi/1 NaH14CO3) to sea water with its natural concentrations of zoo- and phytoplankton, incubating this water in the light, separating zoo- from phytoplankton after 1 h or at the most 2 h and measuring the radioactivity of both. Under such conditions, the concentration of the tracer in phytoplankton can be simplified as a linear function of time, and that of the zooplankton as a parabolic function of time. This simplification leads to an overestimation of grazing of at most 2–3%. Comparisons with the Coulter Counter method are given and discussed.

Notes: Abstract A total of 75 weekly exploited populations of the harpacticoid copepodTisbe holothuriae Humes were exposed to 0.06, 0.3, 1.5, 7.5 or 37.5 μg Cd++l−1, combined with exploitation rates of 10, 30, 50, 70 or 90% under conditions of surplus food supply at 22° C and 30‰ S. An unusually high mortality was observed for some weeks which could not be ascribed to the added amounts of Cd++. A change in properties of supplied water is considered responsible for the unintentional perturbation which offered a further opportunity to study the effect of compensating reactions in stress situations. The results obtained clearly indicate an effect of exploitation rate on responses to detrimental influences. A superior performance has been found in populations exploited at higher rates. The findings are discussed with respect to earlier investigations on the population dynamics ofT. holothuriae.

Notes: Abstract The egg membrane and follicle of the oocytes ofPomatoschistus minutus were investigated by light and electron microscopy. The formation of the cortex radiatus begins in late stage I and is concluded in stage III. In stage II bundle structures appear at the base of the cortex radiatus. These bundle structures cannot be identified in stage III. The cortex radiatus differentiates into the cortex radiatus externus and the cortex radiatus internus. Up to 220 attaching filaments originate in stage II. They are connected with the egg membrane at the animal pole. The attaching filaments are a modified part of the cortex radiatus externus. They consist of two substances which differ in their electron density. The attaching filaments lie between the cells of the follicle epithelium and are probably formed by these cells. They are adapted for attaching the eggs. The follicle epithelium is always single-layered. The cross-section of the spindle-shaped follicle cells is quadratic in stage I and II and quadrilateral in stage III. The cells of the follicle epithelium contain a lot of rough ER and are thus divided into many compartments. The primary oocyte membrane (oolemma) shows considerable pinocytosis activity in stage II and there are many polysomes in the peripheral cytoplasm. Possible functions of the pinocytotic vesicles and the polysomes are discussed.

Notes: Abstract Epifaunal community development on plexiglas panels submerged in Helgoland Harbour (North Sea) was observed over one year. The course of colonization is described, and some data are presented on autecology, reporduction, and growth rate of particular species. About three months after initial settlement, conditions of coexistence in a mixed barnacle-ascidian community began to change increasingly due to heavy competition for space. The colonial speciesBotryllus schlosseri proved to be potentially dominant. Shortly before it attained monopolization by replacing barnacles (mainlyElminius modestus), a major physical disturbance eliminated the fast growing ascidian. The roles of physical factors, of biological interactions, and of historical events in community development are discussed in context with succession theory and other concepts evolved more recently. It is concluded that succession-like processes can occur in subtidal fouling communities, but there the existence of a globally stable climax is unlikely. Generally the concept of multistable points seems to be better applicable to marine ecosystems than that of succession in the classical sense. There is considerable need for further natural history observations and experiments as an empirical basis for current theory and modelling.

Notes: Abstract The distribution of110mAg was studied in various invertebrates of a marine benthic food chain as a consequence of the immersion in contaminated seawater and/or ingestion of radioactive food. The studies on110mAg distribution were carried out at the end of the experimental contamination (when equilibrium was reached) and during the slow stage of elimination. After contamination via the surrounding water, uptake of110mAg occurs mainly in external organs: shells (34%) and mantle (16%) of the bivalveScrobicularia plana, exoskeleton (40%) and gills (38%) of the crabCarcinus maenas. On the contrary, contamination via food is responsible for a considerable accumulation of110mAg in the digestive glands ofS. plana (75%) andC. maenas (56%). Moulting plays an important role in the decontamination of crabs following immersion in radioactive seawater owing to the strong contamination of the exuviae. The elimination of110mAg from the different organs of the animals examined depends upon the mode of contamination: it is generally fast in external organs and slow in the digestive gland. Radiation doses for molluscs and crustaceans were calculated following experimental contaminations by water and food. A significant contamination of external organs is responsible for a radiation dose (in the centre of the test animals) weaker than that instigated by the accumulation of110mAg in the digestive gland. Thus, with regard to contamination, the ambient water is important; but, from the point of view of irradiation, radioactive food is generally more important.

Notes: Abstract As an initial step in a programme designed to investigate factors which are of importance in affecting the behaviour of actinides towards certain invertebrates found in estuarine and marine environments, laboratory procedures have been developed to study the accumulation of americium in three species: the polychaete wormNereis diversicolor, the brackish-water amphipodGammarus duebeni and the harpacticoid copepodTisbe holothuriae. The species chosen are considered representative of groups having wide ecological importance. It was found that large differences in concentration factors occurred for the same organisms, depending upon aging of the contaminated medium; much higher and more variable values being found when uptake was from freshly contaminated solutions than from those aged up to a week. The interaction of specimens with physico-chemical reactions of americium which appear to take place within the first few days after its introduction into water are considered to be responsible for these differences. Uptake from contaminated water that had been allowed to age in the absence of organisms appears to be unaffected by subsequent conditioning by specimens. Americium concentration factors show a strong tendency to increase with decreasing size of the species, varying from over 1000 forT. holothuriae to about 3 forN. diversicolor. The possibility that the mechanisms regulating the uptake of actinides in different species may depend upon pH is briefly discussed.

Notes: Abstract Daily activity patterns ofAstropecten aranciacus, A. bispinosus andA. jonstoni were investigated by means of SCUBA diving. The three species generally showed two peaks of activity, at dawn and dusk. However, the activity pattern was variable, depending upon site, depth and season. Two populations ofA. aranciacus showed only one daily peak at certain times of the year. These peaks were at night in one case, at noon in the other. Light appears to be an important factor governing the activity pattern.

Notes: Abstract Based on previous studies (Klöckner, 1976b) dealing with field investigations on breeding season, choice of substratum, growth and mortality of the sessile filter-feeding tube wormPomatoceros triqueter in Helgoland waters (southern North Sea), data from laboratory experiments on the physiological potential of the polychaete in regard to temperature are presented. Adult worms tolerated temperatures from −3° C (24 h LT 28) to 30° C (24 h LT 50) when heated or cooled in steps of 1 C° d−1; a two-week period of acclimation within 6° to 18° C did not change their tolerance. Standard oxygen consumption and regeneration of the calcareous tube were found to be dependent on temperature, body weight and food supply; acclimation periods of two weeks had no significant influence. Highly increasing metabolic rates were noted between 6° and 18° C (Q10-values up to 6) and a maximum was found between 20° and 24° C (0.32 μg O2 mg−1h−1 and 10.2 μg CaCO3 mg−1d−1); tube regeneration followed a nonlinear regression of y=ax−b when compared to body weight and was reduced by starving animals to less than 50% within 15 days. Filtration activity ofP. triqueter, however, was found to be highly independent of temperature from 12° to 24° C; maximum activity was 1 ml mg−1 h−1 (all data refer to fresh weight). For comparisons with the results of previous field investigations onP. triqueter some intraspecific correlations of the different parameters employed (tube sizes, fresh and dry weight) are presented as exponential functions of y=axb.

Notes: Summary 1. Population indices based on bird censuses (especially line transects) are given for south Finnish forest birds (40 species). The indices refer to 1926–27, 1936, 1936–49, 1952–63 and 1973–77. 2. Population increases were observed to be much more frequent than decreases. The main reason for the changes is presumably that the structure of the Finnish forests has changed considerably in recent decades. Many bird populations are thus probably well adapted to habitat changes caused by forestry. However, certain species need habitats destroyed by modern forestry (e. g. old forests); in consequence, it is necessary to maintain sufficient old forests areas for conservational purposes.

Notes: Zusammenfassung 1. Der Bestand überwinternder Höckerschwäne in Südbayern hat sich nach der Zunahme vor 1970 inzwischen stabilisiert und die Grenzkapazität von rd. 2500 Exemplaren erreicht, wie mit Hilfe der internationalen Wasservogelzählung nachgewiesen werden konnte. Um diesen Wert dürften die Bestände auch in Zukunft schwanken. 2. Zur Abschätzung des Bestandstrends beim Höckerschwan reicht es aus, wenn nur 23 vollständige Zählreihen größerer Gewässer mit etwa 25% des Höckerschwanbestandes berücksichtigt werden. Der Trend erscheint allerdings wegen der Sättigungseffekte in den Populationen der Konzentrationsgebiete etwas zu negativ. Vor allem an den Kleingewässern dürfte es noch zu leichten Zunahmen kommen. 3. Dezember- und Märzwerte geben die Bestandstrends ebensogut wieder wie die Summen über alle Zählmonate von September bis April. 4. Zur Ermittlung der Bestandsgröße sollten kleinere Gewässer auch in Zukunft im Januar und eventuell zusätzlich im März bzw. November gezählt werden. Zählungen in anderen Monaten sind nur sinnvoll, wenn deren Regelmäßigkeit garantiert werden kann, da diese Daten sonst statistisch nur schwer verwertbar sind.

Notes: Zusammenfassung Es wurde überprüft, ob der China-Grünling(Chloris sinica) systematisch ein Bindeglied zwischen dem Grünling(Chloris chloris) und dem Stieglitz(Carduelis carduelis) darstellt. Mehrjährige Gefangenschaftsbeobachtungen an asiatischen und europäischen Stieglitzrassen und an den 3 Grünlingsarten Grünling, Himalaya-(Ch. spinoides) und China-Grünling(Ch. sinica) zeigten folgende Resultate: 1. Der China-Grünling ist ein echter Grünling, der in keinem Verhaltensmerkmal nähere Beziehungen zum Stieglitz zeigt. 2. Die Merkmalsübereinstimmungen zwischen den asiatischen, grauköpfigen Stieglitzrassen und dem China-Grünling in der Flügelzeichnung und Gefiederfarbe beruhen auf einer Parallelentwicklung. 3. Die verschiedenen Rassen des Stieglitzes und die 3 untersuchten Grünlings-Arten bilden zwei in sich geschlossene, ohne Übergangsformen voneinander getrennte Cardueliden-Gruppen. 4. Das generelle Gesangsprogramm, die Festlegung auf eine arttypische, den Einzellauten übergeordnete, rhythmische Gliederung des Gesangs blieb während der Rassenbildung des Stieglitzes und der Bildung der 3 Grünlingsarten unverändert. Alle Stieglitze singen in Strophen, die bei den 3 Grünlingsarten übereinstimmend fehlen.

Notes: Summary Discussions of the evolution of clutch-size in birds have largely ignored the physical characteristics of nests. In the tropics, the size and structure of nests have evolved under the influence of intense predation by nest-predators. One result of selection for inconspicuousness has been a reduction in nest size, in some cases to an extreme degree. It is argued that reduction in nest size has been an important factor limiting clutch-size, and, more generally, that the evolution of clutch-size cannot be fully understood without considering the dimensions and other physical properties of nests.

Notes: Zusammenfassung 1. Die mitteleuropäische, die spanische und die kanarische Gesangsform des Zilpzalps sind voneinander klar verschieden. 2. Die Zilpzalp-♂ von Teneriffa (kanarische Inseln) und aus Mitteleuropa reagieren auf ihre vom Tonband vorgespielten Gesänge wechselseitig wie ♂ verschiedener Arten, d. h., nur einzelne ♂ werden angelockt. 3. Zilpzalp- ♂ aus Mitteleuropa verhalten sich gegenüber der spanischen Gesangsform des Zilpzalps wie gegenüber artfremdem Gesang. Spanische Zilpzalp- ♂ werden von Gesangsformen des Zilpzalps aus Mitteleuropa und den kanarischen Inseln zu einem hohen Prozentsatz angelockt (86,6 und 66,6%). 4. Die Zilpzalp-Populationen in Mitteleuropa, Spanien und auf den kanarischen Inseln befinden sich vermutlich auf verschieden weit fortgeschrittenen Stufen der Artaufspaltung. 5. Interspezifische Kontrastbetonung ist wahrscheinlich nicht die Ursache für die großen Unterschiede zwischen dem Gesang des Fitis und des mitteleuropäischen Zilpzalps.

Notes: Zusammenfassung An zwei Farbformen des australischen Zebrafinken(Taeniopygia guttata castanotis) sollte die Frage geklärt werden, wie sich eine in früher Jugend erfolgte Prägung auf eine bestimmte Gefiederfarbe unter Bedingungen auswirkt, die der natürlichen Lebensweise der Art weitgehend Rechnung tragen. Hierzu wurden in zwei dreiwöchigen Versuchen jeweils je 16 ♂ und 16 ♀ beider Farbformen (wildfarben und weiß), von denen jeweils 50% von der eigenen und 50% von der anderen Form aufgezogen worden waren, in einer großen Freivoliere beobachtet und ihre Paarbildung und die Orientierung ihrer sexuellen Verhaltensweisen verfolgt. Alle ♂ balzten von Anfang an unabhängig von ihrer eigenen Gefiederfarbe fast ausschließlich solche ♀ an, die der Farbe ihrer Aufzuchteltern entsprachen. Ebenso reagierten auch die ♀ nur auf das Balzverhalten von ♂ des prägungsmäßig richtigen Farbtyps. Innerhalb von drei Tagen waren 61 Vögel prägungsgemäß, und nur ein Vogel war nicht prägungsgemäß verpaart; zwei Vögel blieben unverpaart. (Die ungeraden Zahlen sind darauf zurückzuführen, daß bei einem Paar das ♂ prägungsgemäß, das ♀ jedoch nicht prägungsgemäß verpaart war). Das Verhalten der Vögel und die Sozialstruktur der Gruppe waren völlig natürlich und stimmten mit den aus Freilandbeobachtungen bekannten Einzelheiten überein. Einunddreißig Paare legten Eier und zeigten normales Brutverhalten. Zwischen den auf weiße und den auf wildfarbene Gefiederfarbe geprägten Vögeln waren keine Unterschiede (z. B. in der Strenge der Prägung) erkennbar. Die Ergebnisse lassen folgende Schlußfolgerungen zu: Prägung auf die Gefiederfarbe der Aufzuchteltern kann zu einer völligen sexuellen Isolation zwischen den Individuen mit unterschiedlicher sozialer Früherfahrung führen; eine solche Isolation wird durch das Verhalten beider Geschlechter gewährleistet; es besteht keine erfahrungsunabhängige Bevorzugung der natürlichen Gefiederfarbe der Art.

Notes: Zusammenfassung Die Ausdehnung des Jagdgebietes der Rohrweihe hängt neben dem Beuteangebot und der Struktur des Gebietes vom Stadium und der Größe der Brut ab. Die Jagdgebietsgröße, ermittelt in einem Mäusejahr an 5 Paaren zur Brutzeit, schwankte zwischen 300–900 ha. 1973–1975 wurden an 36 Rohrweihenhorsten 1202 Beutereste gesammelt und ausgewertet. Jagdweise, Beutebehandlung sowie das Auswerten der Beuteaufsammlung werden beschrieben. 58 Wirbeltierarten wurden festgestellt. Der prozentuale Anteil von Säugern und Vögeln an der Beute war in den einzelnen Jahren recht unterschiedlich, während der Anteil der Vögel während zweier Jahre 81 bzw. 75% betrug, sank er in einem Mäusejahr auf ca. 20%. Reptilien, Amphibien und Fische sowie Aas und Vogeleier waren im Untersuchungsgebiet von untergeordneter Bedeutung. Die Frage wird diskutiert, ob Rohrweihen, abgesehen von ihrer angeborenen Vorliebe für Vogeleier, als Nahrungs-Spezialisten zu bezeichnen sind. Ferner werden Hinweise aufgezeigt, die auf große Effizienz beim Nahrungserwerb schließen lassen.

Notes: Abstract Sex determination inGammarus duebeni duebeni was analyzed by breeding experiments conducted with individuals obtained from various populations. Sex ratio of progeny depends on genetic factors and photoperiod. Generally, a preponderance of males was noted when offspring were raised under long-day photoperiods, whereas females prevailed under short-day photoperiods (Bulnheim, 1967, 1969). Based on these previous studies the critical daylength, the transition point at which the photoperiodic response switches, was estimated in specimens from a population of the Elbe estuary as ranging between 13 and 14 hours of light per day at 15° C. The susceptibility to photoperiod is assumed to depend on the balance between a system of male and female determining genetic factors that act on a polygenic basis. From various coastal brackish-water populations thelygenic (all-female) strains could be selected. This maternally inherited sex-ratio condition is caused by the transovarially transferred microsporidiansOctosporea effeminans andThelobania herediteria which, independently of each other, exert a feminizing influence on the host's offspring. Either perfectly or imperfectly thelygenic females may occur. The latter produce eggs that are not all infected; hence their progeny are bisexual. As a consequence of the sex-determining influence of the microsporidians males are generally not parasitized. However, some males associated withO. effeminans were found in a strain derived from a population at Bornholm (Baltic Sea). Also, males infested with one or both of the two parasite species occur in some populations ofG. d. celticus, indicating that in these sex determination is not governed by the microsporidians concerned. The feminizing influence of the parasites may be affected by environmental factors. An increase of the ambient salinity level to 25–30 ‰ results in a disappearance ofO. effeminans in the eggs released by infectedG. d. duebeni females. Thus, the normally acting switch mechanism of sex determination is re-established. In addition, long exposures to low temperatures (≦4° C) may have an adverse effect on the vegetative stages of both microsporidians. Owing to this, infected females may produce eggs which are not all parasitized. Consequently, mixed progeny may arise. Studies on the incidence rates of the two microsporidians. comprising 18 populations indicate that the parasites are widespread in their geographical range. Most populations studied in the Baltic Sea area and brackish-water habitats of the German North Sea coast are associated with either one or both of the two microsporidian parasites. Observations on the sex ratio of a population from the Elbe estuary, performed over several years, revealed considerable seasonal fluctuations. The percentages of infected females, however, remained at a fairly constant level during the study period. The results obtained are discussed with reference to the mechanisms of sex determination and differentiation as revealed in other amphipod species, in particular to the interaction of genetic and non-genetic factors and the occurrence of monogeny phenomena.

Notes: Abstract The polychaete wormsPolydora ciliata andP. ligni were investigated with regard to the morphology of their fifth chaetigerous segment, bearing bundles of modified bristles in a special arrangement. The development of these chaetae from late larval to adult stages is described, considering the loss of provisional bristles, the variation of shape caused by the wear and the shedding of old chaetae after losing their function. In addition an epidemic shell disease of the mussel,Mytilus edulis, induced by infestation withP. ciliata is reported.P. ligni was observed to regularly inhabit the inflorescenses of the eelgrass,Zostera marina. The relationships between this plant andP. ligni are discussed.

Notes: Abstract Photo-reception and sensitivity to light were studied in two Japanese hagfishes,Eptatretus burgeri living in shallow water andParamyxine atami living in water of about 100m depth. Both species responded to general illumination by first moving the tail or head and then by swimming. Local illumination revealed that regions most sensitive to light were the skin of the tail in both species and a line of unpigmented skin running down the back ofE. burgeri. The light sensitivity of the lensless eyes, which are situated below the skin, was very weak in both species.P. atami showed shorter reaction time to light thanE. burgeri. No change in skin colour was induced either by almost complete hypophysectomy or by continuous illumination against a white background. Under-water observations with SCUBA revealed that free movingE. burgeri responded well to illumination uncovered during the night, but the ones buried in mud, with only the heads uncovered did not.

Notes: Zusammenfassung Der Bali-Star kommt heute nur mehr in einem 10 000 ha großen Rückzugsgebiet an der NW-Küste Balis (seit 1970 Naturschutzgebiet) vor. Der Bestand ist auf sicher weniger als 1000 Tiere zusammengeschmolzen und wird sich unter den gegenwärtigen Bedingungen auch nicht erholen, sondern eher zurückgehen. Erhaltungsmaßnahmen könnten erfolgreich sein, verlangen jedoch eine völlige Umstrukturierung des betreffenden Landstriches von einem ökonomisch genutzten zu einem echten Schutzgebiet.