ALBERT

Notes: Abstract The theory of complementary variational principles is used to obtain maximum and minimum principles for diffusion problems with Michaelis-Menten kinetics. In an illustrative calculation we obtain an extremely accurate variational solution in good agreement with the numerical solution of McElwain (1978).

Notes: Abstract Necessary and sufficient conditions for primitivity of a product of two Leslie matrices are given. Such a product could be used in modeling the growth of a population governed alternately by two different sets of fertility and survival parameters.

Notes: Abstract Zadeh's transfer function method for linear time-variable systems is used to apply frequency-domain analysis to a periodically time-varying elastance model of the left ventricle. Left ventricular pressure computed from the system function of the time-varying elastance and the phasors of aortic flow shows a typical waveform of the measured ventricular pressure.

Notes: Abstract A theory of noise fluctuations is developed which is applicable to systems of any size in which unimolecular or bimolecular reactions are occurring. The main difference between small and large reacting systems is that in the former the probability of finding a particle in a particular state does not obey a Gaussian distribution, but satisfies a distribution which reflects the mechanism of the chemical reaction. This difference is reflected in the main result of the theory: an autocorrelation function that is expressible as a sum of exponentials, the amplitudes of which are explicit functions of the moments of the distribution. Thus, by using small systems, the autocorrelation function,in principle, allows the elucidation of reaction mechanisms. Numerical simulations indicate that for reacting systems having ten or fewer particles, the deviation of the autocorrelation function from a single exponential should be easily detectable, and that estimates of the first four moments of the distribution should be possible. Accurate inference of the distribution, however, will require further mathematical and experimental advances.

Notes: Abstract The recent mathematical formalization of the concepts of matter and extrinsical energy, which are used for the relational representation of biological systems, is employed in the analysis of the important experimental discoveries of Comorosanet al. related to low energy electromagnetic irradiations on enzyme substrates. By means of the present analysis one of the properties inherent to the experimental phenomena is more precisely exposed, and theoretical developments corresponding to “energetical evolutions” in a biological system (Leguizamón, 1976) may now have an experimental basis. Important limitations are introduced for the validity of the commutativity and associativity of cartesian product of sets, when they represent matter and its linked extrinsical energy. In connection with this last aspect, new important knowledge is obtained for the relational mathematical representation of biological systems.

Notes: Abstract The structure of solutions to a simple spatially dependent population model involving growth and death is investigated. Two forms of motility of the population are considered: (1) random motion only modeled by a Fickian law, and (2) a directed component of motion (chemotaxis), included in addition to the random motion. Under certain growth conditions a traveling wave of constant speed is approached. This speed can be increased by the addition of the chemotaxis with a corresponding increase in the asymptotic population. Development of initial conditions into a wave is illustrated numerically.

Notes: Abstract This paper describes mechanisms of intracellular and intercellular adaptation that are due to spatial or temporal factors. The spatial mechanisms support self-regulating pattern formation that is capable of directing self-organization in a large class of systems, including examples of directed intercellular growth, transmitter production, and intracellular conductance changes. A balance between intracellular flows and counterflows causes adaptation. This balance can be shifted by environmental inputs. The decrease in Ca2+-modulated outward K+ conductance in certain molluscan nerve cells is a likely example. Examples wherein Ca2+ acts as a second messenger that shunts receptor sensitivity can also be discussed from this perspective. The systems differ in basic ways from recent diffusion models. Chemical transducers driven by membrane-bound intracellular signals can establish long-range intercellular interactions that compensate for variable intercellular distances and are invariant under developmental size changes; diffusional signals do not. The intracellular adaptational mechanisms are formally analogous to intercellular mechanisms that include cellular properties which are omitted in recent reaction-diffusion models of pattern formation. The cellular models use these properties to compute size-invariant properties despite wide variations in their intercellular signals. Mechanisms of temporal adaptation can be derived from the simplest laws of chemical transduction by using a correspondence principle. These mechanisms lead to such properties of intercellular signals as transient overshoot, antagonistic rebound, and an inverted U in sensitivity as intracellular signals or adaptation levels shift. Such effects are implicated in studies of behavioral, reinforcement, motor control, and cognitive coding.

Notes: Abstract Large radiation doses to the lung can cause early death from cardiopulmonary insufficiency resulting from radiation pneumonitis and pulmonary fibrosis. A model for early death following inhalation of insoluble radioactive particles is propose. The model is based on three assumptions: (1) early death results from damage to a cluster of cells from a large number of cell clusters at risk, (2) the dose that causes early death depends on how the radiation is delivered in time and (3) the cell clusters at risk to damage are equally sensitive ro radiation. Results from asymptotic theory of extreme values, along with biophysical considerations, suggest that the cumultive distribution function for the absorbed radiation dose to the production of pulmonary injury sufficient to cause early death is best estimated by the third asymptotic distribution without a threshold. This distribution function is identical to the Weibull cumulative distribution function. Data for Beagle dogs after inhaling relatively insoluble forms of alpha- or beta-gamma-emitting particles are shown to support the Weibull model.

Notes: Abstract Models of the human respiratory tract were developed based on detailed morphometric measurements of a silicone rubber cast of the human tracheobronchial airways. Emphasis was placed on the “Typical Path Lung Model” which used one typical pathway to represent a portion of the lung, such as a lobe, or to represent the whole lung. The models contain geometrical parameters, including airway segment diameters, lengths, branching angles and angles of inclination to gravity, which are needed for estimating inhaled particle deposition. Aerosol depositions for various breathing patterns and particle sizes were calculated using these lung models and the modified Findeisen-Landahl computational scheme. The results agree reasonably well with recent experimental data. Regional deposition, including lobar deposition fractions, are also calculated and compared with results based on the ICRP lung deposition model.

Notes: Abstract The completely symmetrical system is defined as having identical transfer coefficients between pairs of compartments and the same loss coefficient for each compartment. The eigenvalues and eigenvector are explicitly found along with the inverses of the system matrix and the matrix of eigenvectors. Many properties, special instances of more general theorems, can be seen at once from the explicit analytic solution of the initial value, washout and washin problems. The system serves as a known case for testing estimation procedures, algorithms for solutions of linear systems, eigenvalue-eigenvector and inversion routines and is of considerable tutorial value.

Notes: Abstract The mathematical structures underlying the theories of organismic sets, (M, R)-systems and molecular sets are shown to be transformed naturally within the theory of categories and functors. Their natural transformations allow the comparison of distinct entities, as well as the modelling of dynamics in “organismic” structures.

Notes: Abstract To explain the sodium conductance change using Wei's dipole model (Wei, 1969), we may expect that during depolarization the dipole's population difference, ΔN, is first reduced and then returns more slowly to its resting value. This paper shows that the experimental results of gating currents support this idea. Such time course of ΔN, however, is not a usual relaxation process. To account for the unusual behavior of ΔN, we propose two additional assumptions: (1) there exists a special coupling system (probably the intramolecular vibrations) whose coupling strength with the dipoles is much stronger than with the thermal bath (intermolecular vibrations), and (2) there also exist “traps” for the dipole's excitation energy so that this energy is transformed into other energy forms at a rate increasing with the increase of depolarization. Experiments suggest that the traps are proteins located at the inner membrane surface.

Notes: Abstract Current research into the dynamics of iterative ecological and biological models has lead to a number of theorems concerning the existence of various types of iterative dynamical behavior. In particular, much study has been done on the dynamical behavior of the “simplest dynamical system”f b(x)=bx(1−x), which is just the canonical discrete form of logistic growth equations found in ecology, sociobiology, and population biology. In this paper, we make use of some of the techniques and concepts of topological dynamics to construct a number of generalized conjugacy theorems. These theorems are then used to demonstrate that the mappingf b has a number of conjugacy classes in which the dynamics of the iterates is equivalent to within a change of variables. The concepts of fitness and survival in logistic equations are then shown to be independent, if we follow certain intuitive definitions for these concepts. This conclusion follows from a comparison of the conjugacy classes of the functionf b and the extinction sets off b.

Notes: Abstract For chemical reactions not at equilibrium but proceeding in the forward direction in the steady state, a result found by a method first introduced by H. G. Britton (1963, 1965) is generalized to prove that if $${{\vec J} \mathord{\left/ {\vphantom {{\vec J} {\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\leftarrow}$}}{J} }}} \right. \kern-\nulldelimiterspace} {\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\leftarrow}$}}{J} }}$$ is the unidirectional flux ratio, $${{\vec J} \mathord{\left/ {\vphantom {{\vec J} {\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\leftarrow}$}}{J} }}} \right. \kern-\nulldelimiterspace} {\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\leftarrow}$}}{J} }}$$ exp (−ΔG/RT). The conditions under which the equality or inequality applies are discussed. If the unidirectional fluxes are not in the steady state, the unidirectional flux ratio is time invariant in certain specific situations. One such important case is for chemical reaction systems with an ordered sequence of reactions. For systems with more than one pathway, $${{\vec J} \mathord{\left/ {\vphantom {{\vec J} {\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\leftarrow}$}}{J} }}} \right. \kern-\nulldelimiterspace} {\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\leftarrow}$}}{J} }}$$ is not constant except for special cases. These results also apply to diffusional and active transport systems.

Notes: Abstract The nonlinear second-order difference equationx n+1=axn(1-xn−1), where 0≦x nX≦1 anda ≧1, is examined from varying points of view, analytical, numerical and geometrical. An analytic expression is obtained for an invariant attracting curveC ∞ (a) in phase space, which becomes the central object of study. This basic curve, which replaces the simple parabolic shape typical of many analogous first-order models, may have a complicated geometrical structure. As the parametera increases,C ∞(a) undergoes transformations characterized by the dynamical descriptions: stable node→stable focus→stable limit cycle →chaotic attractor. Although the limited characterization ofchaos by the appearance of nonperiodic solutions and solutions of arbitrarily large period is relied upon, this appears to be only a simplified approximation of the real behavior of solutions. Trajectories (x n, xn+1),n=0,1,…, are calculated using the related nonlinear planar mapT a(x,y)=(y,ay(1−x)), and regions of persistence and escape are described for characteristic values ofa. The study of persistence, of even more fundamental interest than the associated problems of periodicity and stability, receives special attention. We introduce a geometrical model, similar in many respects to that for the well-known analoguex n+1=axn(1−x n), but having several new and important features. It appears that as the parametera increases in the chaotic regime there are infinitely many intermittent bursts of increase in the probability that any initial point (x 0, x1) will persist in the unit square under successive iterations of the mappingT a, an unexpected property that should be of interest for applications. A discussion of the applicability of these results to population dynamics theory is given, and it is suggested that such equations might find useful application to problems in developmental biology as well.

Notes: Abstract Based on the principle of minimum power, a mathematical model of the functional state of the oxygen transport system is presented. The optimization model minimizes the power expenditure of the heart, bone marrow, lung and other tissues. The model is used to determine the functional parameters of the oxygen transport system in man under both normal and varying barometric pressures. Theoretical results are compared with experimental data.

Notes: Abstract A quantitative model of ion binding and molecular interactions in the lipid bilayer membrane is proposed and found to be useful in examining the factors underlying such membrane characteristics as shape, sidedness, stability and vesicle size at various cation concentrations. The lipid membrane behaves as a bilayer couple whose preferential radius of curvature depends on the expansion or contraction of one monolayer relative to the other. It is proposed that molecular packing may be altered by electrostatic repulsion of adjacent like-charged phospholipid headgroups, or by bringing two headgroups closer together by divalent cation crossbridging. The surface concentrations of each type of cation-phospholipid complex can be described by simple binding equilibria and the Gouy-Chapman-Stern formulation for the surface potential in a diffuse double layer. The asymmetric distribution of acidic phospholipids in most biological membranes can account for the differential effects of identical ionic environments on either side of the bilayer. The fraction of vesicle material which tends to have a right-side-out orientation may be approximated by a normal distribution about the mean curvature. The theory generates vesicle sidedness distributions that, when fitted to experimental results from human erythrocyte membranes, provide an alternative method of estimating intrinsic cationphospholipid dissociation constants and other molecular parameters of the bilayer. The results also corroborate earlier suggestions that the Gouy-Chapman theory tends to overestimate free counter-ion concentrations at the surface under large surface potentials.

Notes: Abstract The “yellow strips” on the cuticle of the Oriental Hornet (Vespa orientalis, Hymenoptera, Vespinae), present photoelectric properties. A mathematical model for the relative changes in resistance as a photoconductive process conforms to the general model for a semiconductor with traps.

Notes: Abstract Damped nonlinear oscillations in biological and biochemical systems are investigated by the extended Krylov-Bogoliubov-Mitropolskii (KBM) method. A review on the extension made by Popov to the KBM method is given and also further improvements are presented. Applications are made to models of oscillating chemical reactions (Lefever and Nicolis, 1971), FitzHugh (1961) equations, and population dynamics (Gatto and Rinaldi, 1977). Comparison to damped oscillating physical and engineering systems is made.

Notes: Abstract The conditions that will allow the lumping together of several age classes in the Leslie model are investigated. We show that if the lumping is to be valid for all population distributions, then the parameters of the model must be periodic. Lumping is valid when the population is in equilibrium, but equilibrium should be tested before the model is lumped.

Notes: Abstract Catastrophe theory is a mathematical theory which, allied with a new and controversial methodology, has claimed wide application, particularly in the biological and the social sciences. These claims have recently been heatedly opposed. This article describes the debate and assesses the merits of the different arguments advanced.

Notes: Abstract Estimates of capillary tracer permeability calculated using multiple indicator data depend upon the particular model adopted to describe blood tissue exchange. The model proposed by Crone (1963) is appropriate when some of the injected tracer diffuses into the tissue but does not return appreciably to the bloodstream before data collection is terminated. Under these conditions extraction of tracer by the tissue depends on a single dimensionless parameter, αcap, defined as the ratio of capillary permeability surface area to water flow. The effects of finite red cell tracer permeability on the Crone model estimate of capillary permeability are examined in the present study. The results indicate that even when back diffusion from the extravascular space is negligible, significant errors in the Crone model estimate can be expected when capillary permeability is relatively high and the ratio of red cell to capillary permeability is less than unity. However, when an aliquot of blood is equilibrated with tracer prior to injection and the dimensionless capillary permeability is relatively low (i.e. αcap ≦ 0.25 for a haematocrit≦50%), the whole blood Crone model estimate of αcap will be within 10% of the actual value, irrespective of red cell permeability. Red cell-plasma exchange for commonly used tracer-organ combinations should not significantly affect Crone estimates of capillary permeability under normal physiological conditions, but may be important in low flow situations.

Notes: Abstract Assuming truncated ellipsoidal geometry for the right and left ventricles, a model is developed for the myocardium enabling biventricular mechanical behavior to be studied. Employing pressure-volume data taken from normal dog hearts and from hearts in which the pulmonary artery has been banded over periods of 2–40 weeks, it is shown that: (a) right ventricular wall stresses are higher than left ventricular stresses; (b) right ventricular wall stress increases initially to a maximum after 3–4 weeks followed by a decline to normal and even subnormal levels, attaining a minimum value at 32–33 weeks; (c) left ventricular stresses behave in a similar manner, attaining their maximum and minimum levels after 7–8 weeks and 32–33 weeks respectively. These results suggest that surgical or medical therapy in patients with hypertrophied ventricles might be more appropriate during the period of wall stress reduction.

Notes: Abstract In this paper we describe a mathematical model of the oscillations of the diaphragm which limits the vitreous body from the anterior segment of the human eye after the lens has been removed in a cataract operation. We study the motion of this diaphragm driven by movements of the eye. Firstly, a mathematical statement of the problem is given and then we solve the problem exactly for a given class of eye movements. From the analysis we deduce that significant oscillations of the membrane are driven by saccades and that it is the angular acceleration of the eye which causes these types of oscillations. A numerical example is given.

Notes: Abstract The Lotka-Volterra system of prey-predator equations is considered with a special type of continuous time delay. In the case of equal diffusion coefficients Hopf’s bifurcation technique is used to show the existence of travelling wave train solutions for the prey-predator system.

Notes: Abstract A mathematical model of prothrombin activation is being proposed which includes the feedback mechanism of thrombin and the alteration of factor V by thrombin. This model is in good agreement with experimental data for the dependence of the rate of thrombin formation on the concentrations of factors V and X a . In particular, it correctly predicts the existence and location of a maximum in both of these cases.

Notes: Abstract A new model of the upper tracheobronchial tree is proposed to account for the three-dimensional nature of the airway system. In addition to the tube length, the tube diameter, and the branching angle, the model includes information on the orientation angle of each tube relative to its parent tube. The orientation angle, defined as the angle between two successive bifurcations, is useful for calculating the gravitational inclination of each tube. The information on orientation angle is further used to construct a binary coding system for identifying individual tubes in the airway tree. The proposed model is asymmetrical, but the same principles can be readily used to construct a symmetrical one.

Notes: Abstract In any control system for which the number of independent controls is smaller than the number of degrees of freedom to be controlled, our choice of control in any state is restricted to a submanifold of smaller dimension than the tangent space. This simple fact has a number of important consequences for questions of biological import; we consider its implications for adaptation, for senescent phenomena and for the determination of tertiary structures of polypeptides through control of certain average properties. We also formulate the Pontryagin Maximum Principle of Optimal control theory in such a way as to inquire whether specific biodynamic systems can be regarded as optimal with respect to rate of accumulation of particular quantities of the system. We find that if this is possible, the quantity in question must play the role of a clock.

Notes: Abstract A computational model to predict deposition of a wide variety of particulate pollutants in several species of mammals is presented. The model incorporates breathing pattern and detailed anatomical models of the respiratory tract based on extensive morphometric measurements of individual airways. The predicted deposition from this general model is in close agreement with observed deposition of monodisperse aerosols in rats. Particle size and density and respiratory breathing patterns are the critical parameters affecting regional deposition.

Notes: Abstract A theory of antigen-antibody induced particulate aggregation is developed by investigating the stability of model systems of particles. Conditions for the formation of large aggregates are derived by imposing the requirement that at equilibrium a statistically significant number of redundant bonds would occur in a reduced monomer-dimer model system. A relationship is obtained which predicts the fractional agglutination in the reduced dimer system as a function of the antigen, antibody and particulate concentrations: $$\frac{g}{{2f c_0 (1 - g)^{2^ - } }} = \frac{{s_1 }}{r} + \frac{{s_1 s_2 }}{{2!r^2 }} + ... + \frac{{s_1 s_2 ...s_j }}{{j!r^j }},$$ wherec 0 is the initial concentration of monomer,f is a proximity factor,g is the fractional agglutination,s i is the average rate of formation of theith bond from an (i−1)th bound dimer, andr is the average rate of dissociation of a single antibody-antigen bond.

Notes: Abstract The roles of the concentrations of the three interacting constituents in the aggregation process (antibodies, antigens and particulates) are analyzed in detail. It is shown that the basic equation derived in Part I is consistent over a broad range of conditions with experimental findings previously reported.

Notes: Abstract A general mathematical model describing the biochemical interactions of the hormones luteinizing hormone releasing hormone (LHRH), luteinizing hormone (LH) and testosterone (T) in the male is presented. The model structure consists of a negative feedback system of three ordinary differential equations, in which the qualitative behavior is either a stable constant equilibrium solution or oscillatory solutions. A specific realization of the model is used to describe the experimental observations of pulsatile hormone release, its experimental suppression, the onset of puberty, the effects of castration, and several other qualitative and quantitative results. This model is presented as a first step in understanding the physicochemical interactions of the hypothalamic-pituitary-gonadal axis.

Notes: Abstract Based upon the transition rate equation of dipoles in the membrane, we deal with two important aspects of interaction of nerve signals: (1) conditions for nerve excitation and (2) frequency spectrum analysis of nerve impulse. Interrelations between signal amplitudes and frequencies are formulated in detail. There are several important conclusions which can be drawn from our calculations. First, toexcite the nerve, low frequencies are generally more effective than high frequencies. Second, tosedate the nerve (i.e. to suppress undesired activities), high frequencies would suit better. Third, harmonics produced through interactions of nerve signals are not necessarily weaker than the fundamental frequencies. The great significance of our theory is that it indicates in principle the feasibility to alter or rewrite the information contents of a nerve message in our body by applying stimulations of appropriate strengths and frequencies. Thus, the theory provides a physical basis and hence some understanding for a new branch of medicine—neuro therapy such as Nogier's auriculotherapy, Lamy's phonophoresis, Voll's electroacupuncture and the fast rising TENS (transcutaneous electro-neuro stimulation).

Notes: Abstract A new physical property, called resonance of the B-type is hypothetically attached to the λ =546 nm irradiated crystalline (small) molecules. In this respect an up or down configuration is assumed for those states obtained through irradiation times that are multiples of 5 sec. With these assumptions, the cellular receptors that may detect these states appear to belong to three classes: the up, down and alternatively mixed up-down. Using the classic formalism of eigenvectors and eigenvalues, a simple spectroscopic type of formula is derived, through which all the possible states of the above characteristic may be obtained.

Notes: Abstract A model of ecosystems with migration is proposed from the viewpoint of flow. This model explains the following two points: (1) How the density-dependent terms in population dynamics arise as a consequence of migration. (2) How the ecosystem exhibits a hierarchy in energy per unit biomass.

Notes: Abstract For precise boundary conditions of biological relevance, it is proved that the steadily propagating plane-wave solution to the Fisher equation requires the unique (eigenvalue) velocity of advance 2(Df)1/2, whereD is the diffusivity of the mutant species andf is the frequency of selection in favor of the mutant. This rigorous result shows that a so-called “wrong equation”, i.e. one which differs from Fisher's by a term that is seemingly inconsequential for certain initial conditions, cannot be employed readily to obtain approximate solutions to Fisher's, for the two equations will often have qualitatively different manifolds of exact solutions. It is noted that the Fisher equation itself may be inappropriate in certain biological contexts owing to the manifest instability of the lowerconcentration uniform equilibrium state (UES). Depicting the persistence of a mutantdeficient spatial pocket, an exact steady-state solution to the Fisher equation is presented. As an alternative and perhaps more faithful model equation for the propagation of certain species properties through a homogeneous population, we consider a reaction-diffusion equation that features a cubic-polynomial rate expression in the species concentration, with two stable UES and one intermediate unstable UES. This equation admits a remarkably simple exact analytical solution to the steadily propagating plane-wave eigenvalue problem. In the latter solution, the sign of the eigenvelocity is such that the wave propagates to yield the “preferred” stable UES (namely, the one further removed from the unstable intermediate UES) at all spatial points ast→∞. The cubic-polynomial equation also admits an exact steady-state solution for a mutant-deficient or mutant-isolated spatial pocket. Finally, the perpetuating growth of a mutant population from an arbitrary localized initial distribution, a mathematical problem analogous to that for ignition in laminar flame theory, is studied by applying differential inequality analysis, and rigorous sufficient conditions for extinction are derived here.

Notes: Abstract The binding of mono-, di- and trivalent cations to negatively charged surfaces is studied within the framework of a modified Gouy-Chapman equation. For any given combination of ions of the above valences, the existence and uniqueness of the solution for the surface potential is shown. The treatment provides the surface potential and charge density. For a system containing only monovalent and divalent ions, analytical solutions are given. When trivalent ions are also present, a procedure based on numerical integration is described. The distance dependence of the electrostatic potential for planar surfaces is given. The calculations provide the amount of cations tightly bound and the amount trapped in the double layer region. The competition between cations for binding to surfaces is elucidated.

Notes: Abstract This paper deals with a model describing the behavior of barium-treatedApalysia neurons. The model is represented by a dynamical system, so-called “complete system”, defined in R4 and depending on a small parameter. The study of this system under zero membrane current conditions was performed with the use of the qualitative theory of singular perturbations. We show that this system has a stable periodic solution of the discontinuous type when the small parameter tends to 0+. A reduced system defined in R3, associated to the complete system was also studied: it corresponds to a constant activation of the inward current. We demonstrate that the corresponding hypothetical cell remains silent under zero current conditions.

Notes: Abstract In the study of chemical modification of enzymes and other biologically active proteins, plots of fractional residual activity as a function of number of groups modified per enzyme molecule are often used to establish a correlation between the chemical modification and enzyme inactivation reactions and to determine the stoichiometry of the modification reaction. This paper presents a critical examination of the underlying theoretical framework of such graphs. Whereas these plots are usually presented as linear functions, it is shown here that the general equation describing the relationship between inactivation and modification contains an exponential term; therefore, in the general case, the plot is actually a curve. It is suggested that caution be exercised in the interpretation of such plots and that equations such as those derived in the text be used to fit theoretical curves to the data, in order to maximize the information gained from chemical modification experiments.

Notes: Abstract This communiction argues that so-called “hermaphroditic” tracer systems, which are neither open nor closed, do not exist physically. The argument is based on the assumption that any observable (possibly nonhomogeneous) macroscopic compartment can be approximated by a compartmentC with a finite number of entry points for the tracer, each associated with an abstract subcompartment ofC. It is shown that the “hermaphroditic” property requires that the mean waiting time be infinite in at least one of the subcompartments, or in a subcompartment elsewhere in the system. A subcompartment with infinite mean waiting time must have some sort of memory, of infinite duration, which knows how long a given particle has been retained, however long that is, and thereby determines its probability of departure. Assuming, as seems likely, that no physical basis exists for such an infinite memory, it follows that “hermaphroditic” systems do not exist.

Notes: Abstract The implication of state space structure on the existence of a repeatable experimentE designed to determine if a states∈L has propertyP or notP is investigated. It is shown that if a state spaceL is connected, then no experimentE is repeatable. This formalism is used to demonstrate that if a propertyP has an associated set of points inL which is dense with dense complement inL, then there exists no repeatable experimentE which can be used to test whethers has propertyP or notP. Other consequences of this formalization are discussed.

Notes: Abstract It has been shown that the resistance of flow and the wall shear increase with the size of the stenosis but these increases are comparatively small due to non-Newtonian behaviour of the blood indicating the usefulness of its rheological character in the functioning of the diseased arterial circulation.

Notes: Abstract The modern theory of generalized Hamiltonian systems is used to construct a unified canonical description of the linear Lagrangian biodynamics introduced by Kerner.

Notes: Abstract The purpose of this paper is to justify an asymptotic method developed for the study of peristaltic transport in a tube of arbitrary cross section. Within the framework of long wave approximation, the three-dimensional nonlinear Navier-Stokes equations are reduced to a sequence of two-dimensional linear boundary value problems of Laplace and biharmonic operators. It is shown that, if a Reynolds number is less than some constant, the solution of the approximate equations is indeed an asymptotic approximation to the exact solution of the problem as the ratio of the maximum radius of the tube to the wave length of the peristaltic motion of the wall tends to zero, and the error estimates are expressed inL 2 norms. Furthermore, under the same condition the exact solution is shown to be unique and stable under arbitrary perturbation of spatially periodic disturbance. Application of the stability condition to peristaltic transport in a tube of circular cross section is given.

Notes: Abstract A mathematical analysis, including existence and uniqueness, is given for some boundary value problems which model the flow of a fluid-solute mixture in a tube which is placed in an interstitium. The model permits an interchange of fluid and solute across the tube walls.

Notes: Abstract The vertebrate nervous system has topographic interconnections in many parts, known for example as retinotopy, somatotopy, etc. It is plausible that modifiable synapses play an important role in forming and refining these connections together with the sensory experiences. To elucidate the mechanism of topographic organization, we propose a simple model consisting of two nerve fields connected by modifiable excitatory synapses. The model also includes modifiable inhibitory synapses. The behavior of the model is described by a set of simultaneous non-linear integro-differential equations. By analyzing the equations, we obtain the equilibrium solution of topographic connections. It is also proved that a part of the presynaptic field which is frequently stimulated comes to be mapped on a large area of the postsynaptic field so that it has a good resolution.

Notes: Abstract The steady-state solution of the equations governing substrate exchange between vascular and extravascular compartments separated by a membrane with finite, symmetrical substrate permeability is presented. Substrate removal from the extravascular compartment by Michaelis-Menten saturation type kinetics with negligible diffusion in the axial and instantaneous diffusion in the transverse directions in both compartments are assumed. It is shown that the solution degenerates into known expressions for special linearized and asymptotic cases. The method of solution is also applied to an extension of the original model incorporating autoregulatory feedback effects upon the process responsible for substrate removal.

Notes: Abstract Global asymptotic stability and equilibrium coexistence is established in two species Lotka-Volterra-type competition when there are time delays in interspecific interaction terms and the intraspecies competition is stronger than the interspecies competition.

Notes: Abstract The realized (observed) value of Landau’s dominance hierarchy index is examined. Under a model of constant pairwise dominance probabilities, the observed index is shown to be a strongly consistent estimator of the underlying (true) index. However, a large number of encounters between animals is shown to be required in order to reduce bias and variance to practical levels except when the pairwise dominance probabilities are near one.

Notes: Abstract The steady state potassium conductance as a function of measured membrane potential difference (p.d.) ϕ of the squid giant axon is corrected for the effect of accumulation of potassium in the periaxonal space. This correction is made on the assumption that several mathematical models of the axon are valid. These are (i) the McIlroy (1975), McIlroy-Hahn (1978) model of membrane conductanceg i(i=K, Na) which is a detailed model of passive transport of ions across the axonal membrane with the aid of mobile, negatively-charged carriers, (ii) the Adelmanet al. (1973) compartmental model of the periaxonal and external bathing-solution spaces, (iii) the enzymatic theory of nervous conduction due to McIlroy (1970 a, b, c), (iv) the Wien dissociative effect of the axolemmic electric field on the weak membrane buffer proposed by Bass and Moore (1968) as a trigger mechanism in nervous excitation and (v) the model (McIlroy, 1979) of the interfacial double-layer p.d.s. which are assumed to exist at the membrane’s surfaces because of the presence of a fixed surface charge. From the correctedg k (ϕ) curves the values of the double-layer p.d.s. of model (v) are deduced and these are shown to lead to a consistent, physically reasonable solution for the distance (approx. 6.8Å) between the fixed surface charges and for the dissociation constants of these sites in their interactions with the ions of the extra-membrane electrolytes. Assuming that the selectivity coefficint of the potassium conducting system for the squid giant axon is approx. 52 it is deduced that the potassium permeability,P ks , of the periaxonal barrier ≈1.37(±0.5)×10−4 cm sec−1 and the thickness of the periaxonal space ≈451±159Å.

Notes: Abstract The effects of peripheral layer viscosity on physiological characteristics of blood flow through the artery with mild stenosis have been studied. It has been shown that the resistance to flow and the wall shear decrease as the peripheral layer viscosity decreases.

Notes: Abstract A study was made of Higgins’ model of glycolysis incorporating molecular diffusion of intermediates, utilizing an earlier conjecture due to Landau. Conditions for the existence of asymptotically stable spatio-temporal periodic solutions are obtained.

Notes: Abstract With the depletion of oil resources in more accessible areas, those of remote regions are being considered or indeed are now being exploited. In many of these regions, especially the polar ones, little is known of the effects such exploitation will have on the environment. But it is known that the ecosystems are often subject to great stress by natural climatic conditions and additional burdens imposed by man may have catastrophic environmental effects. South Georgia, a sub-Antarctic island, has a history of industrial activity mainly concerned with whaling operations that peaked around 1925–1935 but has since declined to virtually nothing. Studies of the ecology of the area provided a unique opportunity to assess the long-term effects that such activities had on the ecosystem. Off the whaling stations a considerable amount of waste material, including fuel oil, was released into the bays and inevitably some of this material was deposited in the sediments. Chemical evidence in the form of both paraffinic and aromatic hydrocarbons still persists in the sediments. The implications of this persistence in relation to the possible influence of the low temperature conditions are discussed. The superficial sediments, marine biota and terrestrial plants, which since 1965 have returned virtually to a pristine state, contain hydrocarbons essentially similar to unpolluted areas around the coast of Britain. Relatively high levels of carcinogenic/mutagenic polynuclear aromatic hydrocarbons in surface sediments suggests a world-wide background of abiogenic hydrocarbons probably disseminated by airborne transport. This appears to indicate that contamination reaches even remote parts of the world in relatively undiminished quantities.

Notes: Abstract The majority of organic chemicals identified so far in the sea are pesticides and products of technical use; most contain chlorine. Only a limited amount of the actual pollutant load is detectable because few data for “unconventional ” pollutants are available. In view of the considerable structural variety of the large number of chemicals produced, there is a need for prediction measurements of bioconcentration and toxic effects. Physico-chemical data may be used for predicting bioconcentration and life-cycle toxicity tests for the estimation of safe levels. The degree of biomagnification via food chains increases with half lives of the pollutants. When comparing pollutant concentrations with toxicological data it becomes apparent that estuaries and coastal areas deserve special concern, whereas pollutant levels of open ocean waters are unlikely to endanger marine life at present.

Notes: Abstract Juvenile turbot,Scophthalmus maximus (L.), were exposed to 0.58 µg 1−1 Aroclor 1254 in seawater, to sediments containing 100, 60 and 1 ppm or fed with cockle containing 20 ppm PCB (polychlorinated biphenyls). Concentration factors for liver and muscle were 104 and 103, respectively, for uptake of PCB from seawater. Contamination of muscle was similar to that of sediments containing 1 and 60 ppm PCB to which turbot were exposed, but less than the 20 ppm in their experimental diet. Contamination of flatfish in the North Sea area is compared with the levels of PCB in the flounder,Platichthys flesus (L.), in the River Thames and predictable values for uptake of PCB from different pathways discussed.

Notes: Abstract A total of 3,785 million 1 of domestic wastes is emptied into the marine waters of southern California each day. Over 85% of these wastes receive primary treatment before discharge into offshore waters. Most of these wastes are discharged at four localities: El Segundo (Los Angeles City), White's Point (Los Angeles County), Newport Beach (Orange County), and Pt. Loma (San Diego City). While some studies were conducted at these localities prior to 1970, all of these sanitation districts have been monitoring the benthic environment since 1971–1973. Some predictions on the effect of domestic discharges on benthic life were made based on the amount of primary effluent discharged per day. If the amount discharged into open oceanic waters is less than 18 million 1/day, then a biological enhancement is noted with an increase in biomass, number of species and specimens, and diversity. If the amount of discharge exceeds 40–180 millions 1/day, then the biomass, number of specimens, and area affected is increased, but the number of species, diversity, and richness is decreased. A faunal index was devised by the personnel at Southern California Coastal Water Research Project to represent these generalities graphically.

Notes: Abstract The Forth estuary is a major estuary on the east coast of Scotland; it receives effluent from domestic and industrial (petro-chemical and distilling) sources. Following a study on the distribution of the macrofauna of the intertidal areas in relation to pollution (McLusky et al., 1978), this paper is concerned with the distribution and abundance of aquatic oligochaetes and the small polychaeteManayunkia aestuarina in relation to estuarine salinity, organic enrichment, and industrial effluent. In the most polluted parts of the estuary oligochaetes are the sole inhabitants of the mudflats; in other less polluted flats they are very abundant. In the least polluted parts the numbers of oligochaetes diminish as the numbers and diversity of macrofauna increase. Estimates of the production of oligochaetes are given.

Notes: Abstract Deep ocean mining for manganese nodules is under development by several multinational mining consortia. Initial estimates of probable environmental effects of this mining were made before any actual operations were conducted. Recent pilot mining tests near Hawaii have provided an opportunity to verify and modify the initial estimates. The two principal initial impacts of mining are in the near surface water associated with increased turbidity caused by mining discharge, and in a relatively limited zone at the sea floor associated with collector traverse. Examples are presented of estimates of reduction in primary production in the turbid plume as well as the contrasting effect of increased nutrients. Effects of the mining collector on benthic populations are considered. The limitations of extrapolation of results obtained during pilot mining tests are discussed.

Notes: Abstract Although logical compromise agreement between all the conflicting users of the sea seems the most obvious way to protect marine life, we have in practice mainly ad-hoc restrictions aimed at protecting habitats or species, or at trying to prevent chemical/physical deterioration of the environment. The establishment of reserves on biological rather than touristic grounds necessitates consideration of the criteria, appropriate to marine life, that should be used. Successful reserve management or species protection measures depend upon distinguishing between natural and man-made changes, an ability that can be enhanced in part by appropriate disturbance experiments. Anti-pollution measures have centred upon effluent input rather than biological effect in the field, with “acceptable discharge levels” being based upon lethal and sub-lethal experimental effects. But the ultimate criteria of environmental well-being are ecological responses at the population and community levels where, unfortunately, many natural and man-made influences produce similar changes. Knowledge of community dynamics and a resulting ability to discount natural events require long-term studies and are slow to accumulate. Thus while short-term sublethal studies proliferate many ecological data remain uninterpretable except in localities of gross and obvious pollution (including tanker accidents). The scarcity of sub-lethal and ecological effects in the field is even supplemented by ecological changes that are contrary to expectations based on pollution loadings. Is this because ecological expertise is still inadequate, or because experimental and environmental loading data grossly overstate the risks and are largely irrelevant at the community level? Can we assume that fears of chronic pollution are unfounded or must we intensify our efforts? If the latter, in which direction?

Notes: Abstract Macrobenthic and meiobenthic communities of an area off the Belgian coast of the North Sea were studied from 1970 until 1975 at 74 stations. On the basis of both macro- and meiobenthos, three zones can be distinguished in the area. The coastal zone is characterized by the macrobenthicAbra alba community, corresponding to the meiobenthicMicroarthridion littorale — Halectinosoma herdmani community, and the open sea zone by the macrobenthicVenus gallina community and the meiobenthicLeptastacus laticaudatus — Paramesochra helgolandica community. In between is a transient zone where elements of both other zones mix. The distribution of these zones is governed by the hydrodynamical regime of the region, especially by the residual and tidal current system of the Southern Bight. Within the coastal zone, the composition of the community is influenced by pollution which especially affects the epibenthic detritus-feeders of the meiobenthos. The spatial stability of parameters describing community structure can be used for monitoring changes. Temporal characteristics of these parameters could not be investigated properly, but diversity seems to be much stabler than biomass.

Notes: Abstract Three eulittoral algae(Ulva lactuca, Porphyra umbilicalis, Chondrus crispus) and one sublittoral alga(Laminaria saccharina) from Helgoland (North Sea) were cultivated in a flow-through system at different temperatures, irradiances and daylengths. In regard to temperature there was a broad optimum at 10–15° C, except inP. umbilicalis, which grew fastest at 10 °C. A growth peak at this temperature was also found in four of 17 other North Sea macroalgae, for which the growth/temperature response was studied, whereas 13 of these species exhibited a growth optimum at 15 °C, or a broad optimum at 10–15 °C. Growth was light-saturated inU. lactuca, L. saccharina andC. crispus at photon flux densities above 70 µE m−2s−1, but inP. umbilicalis above 30 µE m−2s−1. Growth rate did not decrease notably in the eulittoral species after one week in relatively strong light (250 µE m−2s−1), but by about 50 % in the case of the sublittoralL. saccharina, as compared with growth under weak light conditions (30 µE m−2s−1). In contrast, chlorophyll content decreased in the sublittoral as well as in the eulittoral species, and the greatest change in pigment content occurred in the range 30–70 µE m−2s−1. Growth rate increased continuously up to photoperiods of 24 h light per day inL. saccharina andC. crispus, whereas daylength saturation occurred at photoperiods of more than 16 h light per day inU. lactuca andP. umbilicalis.

Notes: Abstract The muddy sediments of the sublittoral area of the inner German Bight are inhabited by a specialized macrofauna with few species. Long-term investigations on community and population dynamics have shown that the majority of this fauna are very susceptible to environmental stress (e. g. oxygen deficiency), and that the impoverishment trend recorded in 1977 has continued. The special hydrographic conditions of the inner German Bight, especially a long flushing time and the possibility of thermohaline stratifications, together with its function as a sediment trap are discussed. It is proposed that such areas should be considered as sensitive, and hence be protected from avoidable additional stress, e. g. introduction of wastes. This proposal is discussed with regard to the dangers arising from the view that muddy areas enriched with organic matter are inhabited by organisms preadapted to the decomposition of additional waste matter.

Notes: Abstract Various physiological and biochemical methods have been proposed for assessing the effects of environmental perturbation on aquatic organisms. The success of these methods as diagnostic tools has, however, been limited. This paper proposes that adenylate energy charge overcomes some of these limitations. The adenylate energy charge (AEC) is calculated from concentrations of adenine nucleotides ([ATP+½ADP]/[ATP+ADP+AMP]), and is a reflection of metabolic potential available to an organism. Several features of this method are: correlation of specific values with physiological condition or growth state, a defined range of values, fast response times and high precision. Several examples from laboratory and field experiments are given to demonstrate these features. The test organisms used (mollusc species) were exposed to a variety of environmental perturbations, including salinity reduction, hydrocarbons and low doses of heavy metal. The studies performed indicate that the energy charge may be a useful measure in the assessment of environmental impact. Its use is restricted, however, as several limitations exist which need to be fully evaluated. Further work relating values to population characteristics of multicellular organisms needs to be completed before the method can become a predictive tool for management.

Notes: Abstract One hundred years ago the striped bassMorone saxatilis was introduced in the San Francisco Bay estuarine system from the east coast of the United States. It was part of our national policy at the time to transplant all potentially useful species everywhere else. The policy was facilitated by completion of the transcontinental railroad in 1869. As a result, the present ichthyofauna of the San Francisco Bay area is largely alien. Introduction of eastern oystersCrassostrea virginica resulted in the inadvertent introduction of many species of invertebrates. Identification of these introduced species was not realized as a problem until recently, and no one knows how many exotic species there are. In other parts of the world there are examples of similar introductions, e.g.Crepidula fornicata andRhithropanopeus harrisi in Europe. Although it is now the policy to frown upon and prohibit introductions, they cannot be prevented and the process still continues, as witnessed by the examples ofElminus modestus in Europe andPalaemon macrodactylus in California. In the USA the recently developed idea of “mitigation,” the artificial replacement of disturbed or destroyed areas by development of quasi-natural areas in compensation, has been accompanied, at the hands of inexperienced practitioners, by potentially dangerous introductions of exotic species. The assumption, for example, that cordgrass(Spartina) should be equally beneficial everywhere in the world has led to the disrupting introduction of potentially hybridizing species in New Zealand and aggressive immigrants in Oregon marshes. This situation calls for more sophisticated understanding of the role of introduced species in natural aquatic ecosystems, and a higher degree of competence in systematic biology.

Notes: Abstract Management of ocean pollution must be based on the best available scientific information, with adequate consideration of economic, social, and political realities. Unfortunately, the best available scientific information about pollution effects on fisheries is often fragmentary, and often conjectural; therefore a primary concern of management should be a critical review and assessment of available factual information about effects of pollutants on fish and shellfish stocks. A major problem in any such review and assessment is the separation of pollutant effects from the effects of all the other environmental factors that influence survival and well-being of marine animals. Data from long-term monitoring of resource abundance, and from monitoring of all determinant environmental variables, will be required for analyses that lead to resolution of the problem. Information must also be acquired about fluxes of contaminants through resource-related ecosystems, and about contaminant effects on resource species as demonstrated in field and laboratory experiments. Other possible management activities include: (1) encouragement of continued efforts to document clearly the localized and general effects of pollution on living resources; (2) continued pressure to identify and use reliable biological indicators of environmental degradation (indicators of choice at present are: unusually high levels of genetic and other anomalies in the earliest life history stages; presence of pollution-associated disease signs, particularly fin erosion and ulcers, in fish; and biochemical/physiological changes); and (3) major efforts to reduce inputs of pollutants clearly demonstrated to be harmful to living resources, from point sources as well as ocean dumping. Such pollution management activities, based on continuous efforts in stock assessment, environmental assessment, and experimental studies, can help to insure that rational decisions will be made about uses and abuses of coastal/estuarine waters.

Notes: Zusammenfassung Von einer kleinen in Straßenbäumen nistenden Population in der Agrarlandschaft bei Braunschweig wurden 1961–65 sämtliche Bruten erfaßt. Die Legezeit erstreckte sich von (April) Mai bis September, wobei 69% (s=13,2%) der Gelege (n=106) in den Monaten Juli—September begonnen wurden und der Juli in allen Jahren Maximum und Median aufwies. Es besteht Übereinstimmung mit den umfassenden Ergebnissen an englischen Ringeltauben (Murton). In Deutschland wurde der Schwerpunkt der Legezeit mit Mai-Anfang Juli (Niethammer 1942) bisher allgemein zu früh angenommen.

Notes: Zusammenfassung Der Gesang von Blaumeisen-Populationen in Mitteleuropa, Spanien, Marokko und auf Teneriffa wurde miteinander verglichen (Abb. 1). In Süddeutschland und auf Teneriffa wurden Klang-Attrappen-Versuche durchgeführt. 1. Der Blaumeisen-Gesang ist in Marokko und auf Teneriffa sehr ähnlich. Er unterscheidet sich vom Blaumeisengesang in Europa (Mitteleuropa und Spanien) in folgenden Eigenschaften (2.–4.): 2. Ihm fehlen „phrasierte“ Strophen (Abb. 2 a–c, e, 3, 4 a, b, f, g), also Strophen, in denen dasselbe Element mindestens viermal nacheinander wiederholt wird. 3. Er enthält mehr verschiedene Elemente (Abb. 5, 7). 4. Die interindividuelle Variation ist größer (Abb. 6, 7). 5. Die Unterschiede zwischen dem Blaumeisen-Gesang in Europa und auf Teneriffa lassen sich nicht mit der Kontrast-Betonungs- und der Kontrast-Verlust-Hypothese nachLack &Southern (1949) undMarler (1960) erklären. Die Lernentzugs-Hypothese erklärt sie besser. 6. Die Blaumeisen von Teneriffa und Marokko sind sehr nahe miteinander verwandt, aber vermutlich sind sie von den europäischen Blaumeisen artlich nicht getrennt.

Notes: Zusammenfassung An zwei Brutplätzen wildlebender Schleiereulen wurde erstmalig mit Video-Überwachungsanlagen und Infrarotlicht eine störungsfreie Beobachtung über Fernsehschirm „rund-um-die-Uhr“ durchgeführt und durch Magnetbandaufzeichnungen von Bild und Ton ergänzt. Die verschiedenen Lautäußerungen (insgesamt 18) konnten so in ihrem jeweiligen ethologischen Zusammenhang, in der sich verändernden Häufigkeit während der Brutphase, in ihrer ontogenetischen Entwicklung und als Klangspektrogramme erfaßt werden. Ergänzend wurden Befunde von Gefangenschaftstieren einbezogen. Die Lautäußerungen lassen sich in folgende 5 Gruppen zusammenfassen: 1. Die Revierrufe (glatte und rauhe Kreischrufe, Schnurren, Revierverteidigungsschrei) entsprechen in ihrer sozialen Funktion dem Gesang. In der Balzphase (ca. 6 Wochen vor Eiablage) ist die Häufigkeit von Revierrufen besonders hoch (Abb. 2). 2. Die Abwehrlaute (Drohrauschen, Fauchen, Schnabelknappen, Angstschrei) dienen zur Abwehr und Einschüchterung von Beutefeinden vor allem im Nestbereich. Besonders auffällig und wirkungsvoll ist das laute und langgezogene Drohrauschen, das anderen Eulen fehlt. Von „unerfahrenen“ Jungeulen wird das Drohrauschen eine Zeit lang auch gegenüber dem ankommenden Elternvogel geäußert (Abb. 6). Spezielle Warn- und Entwarnungsrufe konnten wir nicht feststellen. 3. Die Bettel- und Fütterungslaute (Bettelschnarchen und Gluckern) helfen die Aktionen des Elternvogels und der Jungtiere während der Fütterung zu koordinieren. Das Gluckern wird sowohl von ♀ und ♂ als erstaunlicherweise auch gelegentlich von halbwüchsigen Jungvögeln geäußert (Geschwisterfütterung) und löst die Bettelaktivität aus. Nach dem Ende der Huderphase wird das Gluckern von den Eltern nicht mehr geäußert (Abb. 13). Das Bettelschnarchen der Jungtiere dient außerdem den Elternvögeln als Stimulanz für die Beutefangaktivität und den Jungvögeln, nachdem sie ausgeflogen sind, zur akustischen Kontaktwahrung. 4. Die sozialen Kontaktlaute (Zirpen, Girren, Stimmfühlungsschnarchen, Paarungsschnarchen des ♂, Paarungsstakkato des ♂, Paarungslaut des ♀) stellen ein breites Spektrum von Zirp-, Gacker- und Schnarchlauten dar und werden vor allem während interindividuellen Aktionen im Nestplatzbereich geäußert: In der ersten Nestlingsphase, während der die Küken noch geschlossene Augen haben, ist das Zirpen der Jungen ein Erregungslaut, der beim ♀ Brutfürsorge auslöst (vgl. Abb. 18). Später wird es vorwiegend während sozialer Gefiederpflege und während des „Schnäbelns“ geäußert. Das Stimmfühlungsschnarchen des ♂ und des ♀ und das Girren des ♂ dienen der akustischen Kontaktaufnahme der Geschlechtspartner aus geringer Entfernung. Die Paarung wird in der Regel durch das ♂ mit einem eigenartig gefiepten Paarungslaut eingeleitet und begleitet, während das ♂ das dem Fütterungsgluckern ähnelnde Paarungs-Stakkato hören läßt und mit dem Paarungsschnarchen abschließt. Gelegentlich wird die Paarung auch durch das ♂ mit dem Girren eingeleitet. Paarungen und Paarungslaute können erstaunlich lange nach der Phase der Eiablage beobachtet werden (Abb. 24). 5. Von einigen klanglich prägnanten Lauten (Flöten, Krächzen, Quietschen) der halbwüchsigen jungvögel ist die Funktion unklar geblieben. Auf die große Variabilität des Klangcharakters und auf die Variabilität der Häufigkeit der Rufe ist hinzuweisen. Trotz erkennbarer Homologien zwischen verschiedenenTyto-Rufen und trotz auffallender Ähnlichkeiten zwischen Tytoninen- und Striginenrufen sind Evolutionsabläufe und Verwandtschaftsverhältnisse aus den Lautäußerungen nicht ableitbar.

Notes: Summary Agonistic displays were studied in the Java Finch. In common with other passerines, supplanting attacks and head-forward displays were observed. However, head-twisting and head-waving as aggressive signals appear to be unique to the species. Backward-waving, another display observed, occurs also in the Cutthroat Finch. Head-twisting, head-waving, and backward-waving are present in juvenile begging postures which have apparently been ritualized and used as aggressive displays by adult Java Finches

Notes: Zusammenfassung Nach Beginn der Eiablage wurden die Nisthöhlen mit 14 cm Durchmesser des Brutraumes gegen solche mit 9 cm sowie die vorhandenen Eier ausgetauscht. Die Größe der Vollgelege entsprach daraufhin der Größe des Nestes nach dem Austausch.

Notes: Summary Observations on the wing moult of Le Vaillant's CisticolaCisticola tinniens in South Africa indicate that the remiges are replaced once a year only, during the post-nuptial moult.

Notes: Abstract InMytilus edulis, accumulation and loss of Cd were analyzed under experimental conditions. Cd uptake by the whole soft body is linear, increasing significantly with increasing Cd concentrations in the uptake medium. Until 100 µg Cd l−1, neither limitation of uptake nor any saturation process can be observed. Loss of Cd, measured after transfer of experimentally contaminated mussels to natural sea water, is exponential; biological half lives vary between 14 and 29 days. Gills are the primary sites of Cd uptake from the water, whereas in mid-gut gland, kidney, and mantle the uptake is retarded during the first few days. The mid-gut gland not only bears the main body load of Cd, but also shows the highest Cd concentrations. Gel chromatographic studies of mid-gut gland proteins reveal that Cd is eluated over the whole molecular weight range. Three metallothionein-like proteins with molecular weights of 6,600, 13,200, and 21,000 Dalton could be established. However, they cannot be taken as effective detoxification proteins, because more than 50% of the accumulated metal is bound to high molecular weight proteins.

Notes: Abstract The chlorophyceanUlva lactuca L. was grown in the laboratory in unialgal culture to sufficient size so that up to 70 discs, 24 mm in diameter, could be punched out of a single plant. Using such discs,U. lactuca was then tested with various concentrations of Cd under continuous-flow conditions. A concentration of 4.5 ppm Cd was lethal toU. lactuca within 6 days. Control discs in unpolluted water increased in diameter at a rate of 8 to 13 % day−1 over a 6-day period. At sublethal concentrations of Cd a sharp reduction in growth rate was observed at increasing concentrations up to approximately 0.3 ppm Cd, whereas from 0.3 ppm Cd to the lethal concentration the reduction of the growth rate was significantly less. Reduction in photosynthetic performance corresponded closely to the reduction in growth rate. At ambient concentrations of 0.8 ppm Cd, the plants concentrated Cd by a factor of approximately 50 in 6 days. Much higher concentration factors were attained in lower ambient concentrations. After removal from Cd-polluted water into flow-through culture in unpolluted water, a subsequent loss of Cd was indicated and the plants recovered rapidly. Plants exposed up to 3 d to 0.7 ppm Cd recovered sufficiently to produce viable gametes 7 days after removal from Cd. Because it has a relatively short life span and apparently loses Cd subsequent to exposure to Cd-polluted water,Ulva lactuca is not recommended as an alga for monitoring in-situ environmental pollution.

Notes: Abstract The marine flagellateDunaliella bioculata, which is easily cultivated under laboratory conditions, is a suitable organism for assessing the importance of the radioactive contamination by3H bound to organic molecules. We have studied the uptake of the following tritiated precursors: thymidine-methyl-3H, adenine-2-3H, uridine-5-3H, l-leucine-4-3H, glycine-2-3H, l-arginine-3.4-3H, 1-aspartic acid-2. 3-3H, 1-phenylalanine-2.3-3H, D-glucose-2-3H and D-glucose-6-3H. Under the experimental conditions (2000 lux; incubation time 30 min), all tritiated molecules are taken up byD. bioculata. Their intracellular concentration may reach that of the external medium. However, leucine and adenine accumulate in the algae: their respective concentrations are 10 and 100 times higher than in the culture medium. The molecular distribution of3H has been studied by various biochemical techniques and by sieve chromatography on sepharose 4B. It has been found that more l-leucine-4-3H is incorporated into acid and acetone soluble substances than into proteins. Adenine-2-3H is mainly incorporated into macromolecules of biological significance (RNA, DNA). CsCl gradient centrifugation has shown that the total DNA ofDunaliella is constituted by a major (ϖ=1.707 g/cm3) and by a minor (ϖ=1.693 g/cm3) component.

Notes: Abstract Distribution of hydrocarbons from the “Amoco Cadiz” oil spill in sublittoral sediments, north of Brittany. The quantitative distribution of hydrocarbons in the sublittoral sediments, north of Brittany (France), was followed and recorded for the first year after the spill (March, 1978). Following preliminary observations in spring of 1978, 250 stations were sampled in August from the Bay of Lannion to Portsall at water depths down to 70 m. Subsequently, 40 stations were studied at three-month intervals. During the summer of 1978, the widest polluted sublittoral areas were localised in the Bays of Morlaix and Lannion down to depths of about 30 m and even deeper in some places. In these two bays, the distribution of hydrocarbons showed: (1) deposition near the coasts hit by the slicks, mostly after adsorption by fine sedimentary particles; (2) redistribution of particulate and adsorbed oil towards low hydrodynamic energy areas favourable to deposition of fine particles. In autumn and winter, the coarse sediments became progressively less polluted. Oil, often in significant quantities, remained or was reconcentrated in the fine sediments of the inner bay parts. Consequently, the hydrodynamic structure ot the area (waves, tidal currents) has played an important role in the deposition and redistribution of the hydrocarbons on sublittoral bottoms.

Notes: Abstract The long-term effects of different cadmium (0.2 and 0.4 ppm) and salinity levels (30, 25, and 20 ‰ S) on growth and egg-mass production ofOphryotrocha labronica (La Greca & Bacci) were investigated over three generations. Low salinity levels and the presence of cadmium resulted in reduced growth rates, prolonged times to reach sexual maturity, and reduced size at maturity. Three-way analysis of variance showed significant interaction effects of generation and cadmium for the different growth processes tested. Using response-surface methods, 0.2 ppm cadmium was shown to have a greater effect on growth rate at the third generation than the first and second generations at the three salinities tested. Increased effects were observed from first to second generation at 0.4 ppm cadmium and 30 and 25 ‰ S, whereas effects decreased from second to third generation. At 0.4 ppm cadmium and salinity of 20 ‰ the first generation was not able to produce viable larvae.

Notes: Abstract Coscinodiscus granii Gough was cultivated at low cell densities in aged Atlantic sea water containing very little dissolved organic carbon; the water was enriched with low levels of nutrients but no chelators were added. Cadmium additions provided final concentrations of 0.1 to 26.5 µg Cd l−1, zinc being kept constant at a level of 38 µg Zn l−1. Carrier-free109Cd and65Zn were used as tracers for the two metals. Growth in terms of cell numbers and primary productivity capacity, using the14C uptake rate, was followed during the exponential growth phase for the first 5 days of the experiment and then for a further 3 days during the stationary phase. On each day, the metal contents of the cells were determined. Cadmium concentrations of 20 µg Cd l−1 and more resulted in growth inhibition whereas 17.5 µg Cd l−1 reduced the growth only slightly. The physiological state of the cells influenced the heavy-metal uptake per cell at sublethal Cd levels. Dead cells had a higher heavy-metal concentration than living cells. Microscopical observations revealed that cells just about to divide were less sensitive to a given toxic heavy-metal concentration than cells which had recently divided. This might have been due to different surface/volume ratios.

Notes: Abstract The present paper reports the results of experimental work undertaken using the brackish-water amphipodGammarus duebeni duebeni and the transuranium nuclide americium-241. Data on the accumulation of this actinide showed that the larger fraction of the total body burden is associated with the exoskeleton. It was found that the body burden remained constant in the range pH 8.0–6.5 even though the water concentrations changed markedly. It would thus appear that the concept of a concentration factor should be re-examined and it is proposed that a factor should be defined in terms of environmental and chemical parameters which represent the bioavailable fraction of the actinide. The effect of americium on survival and moulting was studied at two activity concentrations; the dose rates and absorbed doses under the experimental conditions employed have been estimated. The differences in survival rates between the control and irradiated groups were statistically analyzed and the significant difference at the higher concentration is believed to be due to a synergism between physiological stress and radiotoxicity of americium rather than the chemical toxicity of the element.

Notes: Abstract In October 1977 an investigation was initiated of the qualitative and quantitative composition of the fauna of the eelgrass (Zostera marina) beds at Roscoff. Samples were taken in 2 seagrass beds at different tidal levels in order to follow numerical changes in the course of the year. In March 1978 the area of study was struck by the oil slick of the tanker “Amoco Cadiz ”. For this reason sampling has been continued at the same frequency. The tabulated results show clearly that the oil slick had a profound but selective influence on the various animal groups; some of them disappeared while others were apparently unaffected. Rapid recovery of some species has taken place, but re-establishment of other species, particularly the filter feeders has not been observed. The very diverse amphipod fauna has disappeared, and has been replaced by a population ofPherusa fucicola andGammarus locusta; the latter was absent in the year before the oil disaster took place.

Notes: Abstract Marine fish and shellfish constitute important natural resources. Provided they are wisely exploited, they are not liable to exhaustion but continue to renew themselves. Wise exploitation requires sound management, and for such management one should be well informed about the factors governing the fluctuations in the stocks and about the costs of exploitation. A century of scientific fisheries research provided a wealth of information on reproduction, migration and growth of commercially important species of fish and shellfish and about the losses the stocks suffer through natural causes such as predation, diseases and parasites, and through the fishery itself. Such information is available for areas which are intensively fished. In fertile waters, the approximate growth increase of fish stocks is some 15 % by weight year−1. If one were to harvest this 15 % only, to be considered as interest on this natural capital, and to leave the capital itself untouched, one could go on fishing for ever. There would be no overfishing or stock depletion. For sound management we need not only ecological data but also information on economic fishery aspects, e. g. on size and power of the fleet, type of fish-finding apparatus installed, costs of netting and wages, fuel required per fishing trip, and on the capital invested. Further we need statistical information on the landings and on the proceeds. Such information is available in countries which participate intensively in fishing. Therefore, one would assume that governments which are well informed by their fishery biologists about fluctuations in stocks of fish and shellfish and by their economists on various aspects of the exploitation would apply sound management to ensure that fishing may continue for many years to come without depletion. A number of examples related to the North East Atlantic area, where intensive fishing is carried out and from where a wealth of scientific information is available, makes clear that cases of sound management are hard to trace.

Notes: Abstract The process of coastal zone management in the United States has progressed to the point that it is now possible to embrace whole coastal ecosystems in management programs. The structural and dynamical features of the ecosystems have to be known before management can succeed. Furthermore, it is necessary to disaggregate the systems into subsystems. The following six subsystems have been used as the best compromise between scientific and administrative needs: the watershed terrain, the land drainage system, the coastal basin, the basin floor, the coastal waters, and the ocean. The Apalachicola National Estuarine Sanctuary in Florida is used as a case history of a managed ecosystem.

Notes: Abstract The effect of pulp and paper mill waste discharges in the Swale, a tidal channel on the southeast coast of England, has been studied. A pulsing tidal movement in the Swale results in effluent being trapped within the estuary for up to 20 days. This has resulted in adverse effects on the quality of the water and sediment along a substantial part of the estuary with the greatest effect occurring east of the mill in the direction of the residual current. A reduction in the dissolved oxygen concentration occurred along a 13-km stretch of the estuary with mean values falling to 53 % saturation near the mill. High levels of organic matter in the sediment reflect the deposition of material from the mill effluent stream and loss on ignition values of up to 12 % were found east of the mill, falling to 5 % within 4 km northwest of the mill. The macrofauna of the intertidal mudflats was typical of a stressed environment with a low number of species and with a few being represented by large numbers of individuals. The dominant species was the sabellid polychaeteManayunkia aestuarina which reached peak numbers of over 1.5 million m−2, 1.5 km east of the mill. An increase in the total biomass near the mill is thought to be associated with organic enrichment from the mill wastes.

Notes: Abstract Since 1958 the occurrence of flounder (Platichthys flesus L.) and smelt (Osmerus eperlanus L.) in the lower River Elbe has shifted gradually toward the mouth of the river into the North Sea; this may be due to periodical deprivation of oxygen and fluctuating peaks of toxic nitrite concentrations. The interior organs of both fish species caught in the Elbe estuary were examined. Macroscopic inspections revealed discolouring of the liver to be most pronounced in specimens 2–3 years of age. Cross-sections of the liver demonstrated histopathological symptoms of oedematous degeneration in smelt, and extreme lipoid vacuolation in flounder increasing with size and age of the fishes. The intestine of both species investigated showed massive desquamation defects of the mucosa, occurring in smelts shortly after hatching, and in flounders after immigration into the estuary. The observations made suggest the influence of toxic compounds distributed in the aquatic environment on the health of both species.

Notes: Abstract Sublittoral hard bottom biocoenoses in Balsfjord, Norway (69°31′ N, 19°1′ E), were monitored using underwater stereophotogrammetry. The study includes manipulation of natural densities of organisms and testing the importance of biological interactions and “key species ” for the structure of biocoenoses. Underwater photography has the advantages of being a non-destructive method, but it is selective because small or hidden organisms cannot always be observed. Field experiments with exclusion of organisms from cages seem suitable for testing hypotheses concerning which animals are “key species ” in certain biocoenoses. Sea-urchins(Strongylocentrotus droebachiensis, S. pallidus) were suspected to be “key species ” in the present study, and their removal from cages caused an increase in abundance of barnacles(Balanus balanoides), the limpetAcmaea testudinalis and algal cover.

Notes: Abstract The shell-inhabiting, marine algaOstreobium quekettii Bornet & Flahault is a distinct species reproducing by zoospores with four flagella. Sporangium formation and the development of zoospores are described. The material obtained from Helgoland (North Sea) is assumed to be identical with the type specimen from the French Atlantic coast.O. quekettii is said to be of worldwide distribution; in the absence of further information, it must be doubted whether other finds reported to belong to this species are identical with the type species.