Showing papers by "Ludwig Maximilian University of Munich published in 1972"

Symmetric binary B-Trees: Data structure and maintenance algorithms

Abstract: A class of binary trees is described for maintaining ordered sets of data. Random insertions, deletions, and retrievals of keys can be done in time proportional to log N where N is the cardinality of the data-set. Symmetric B-Trees are a modification of B-trees described previously by Bayer and McCreight. This class of trees properly contains the balanced trees.

Perivascular Potassium and pH as Determinants of Local Pial Arterial Diameter in Cats A MICROAPPLICATION STUDY

Abstract: The effects of and the interaction between local perivascular variation in potassium and bicarbonate concentration on the diameter of pial arteries were studied in cats by the microapplication technique. At 11 mEq/liter of bicarbonate, a direct correlation existed between vascular diameter and K+ concentrations between 0 and 10 mEq/liter. At K+ concentrations between 10 and 20 mEq/liter, no further increase in vascular diameter was observed. At a K+ concentration of 5 mEq/liter, an inverse relationship existed between pial arterial diameter and perivascular bicarbonate concentrations between 0 and 22 mEq/liter. At K+ concentrations of 0 and 10 mEq/liter, the pial arterial diameter was determined strongly by the K+ concentration and was only slightly, if at all, influenced by bicarbonate concentrations between 5 and 22 mEq/liter. At lower bicarbonate concentrations the local acidity induced a marked vasodilation. The results indicate that the diameter of pial arterioles in cats is affected by periarteriola...

Sexual and Other Long-Term Aspects of Imprinting in Birds and Other Species

Abstract: Publisher Summary Most of the evidence for long-range aspects of imprinting concerns the early establishment of sexual preferences, usually referred to as “sexual imprinting.” As with filial imprinting, most data are available for certain species of birds. They can be divided into two groups: intraspecific sexual imprinting and interspecific sexual imprinting. The chapter discusses the four main criteria that are the characteristic for imprinting: (1) it can take place only during a restricted time period of the individual's life, the sensitive period, (2) it is irreversible— that is, it cannot be forgotten, (3) it involves learning of supra-individual, species-specific characters, (4) it may be completed at a time when the appropriate reaction itself is not yet performed. The amount of generalization found in sexual imprinting cannot be explained due to inability to discriminate between individuals, because it has been proved, for example, in zebra finches-that after pair formation the birds may well develop a definite individual preference for a particular female. The establishment of sexual preferences through imprinting seems to be independent of conventional sexual reward. The chapter surveys some other contexts in which juvenile experience has been proved to exert a crucial influence on adult behavior, and also discusses: (1) the significance of the early determination of sexual preferences for the general concept of imprinting and (2) the biological function and possible evolutionary consequences of sexual imprinting.

Direct Measurement of the Vibrational Lifetimes of Molecules in Liquids

Abstract: A normal molecular vibration is strongly excited by a picosecond light pulse. The rise and decay of the excess population of the first excited vibrational state (electronic ground state) is observed with a delayed probe pulse. These measurements give, for the first time, values of the lifetimes of molecular vibrations in liquids.

Gesang des Männchens und Lautschema des Weibchens bei der FeldheuschreckeChorthippus biguttulus (Orthoptera, Acrididae)

Abstract: 1. Der Gesang der FeldheuschreckeChorthippus biguttulus ist ein charakteristisch amplitudenmoduliertes Lautmuster (Abb. 2): Der Spontangesang besteht aus 1–5 (meist 3) Versen und jeder Vers aus 20–60 Silben (u.a. Faber, 1929). Die Silben sind ihrerseits aus Pulsen aufgebaut, was besonders im Gesang einseitig amputierter Mannchen deutlich zu erkennen ist, und zwar bis auf seltene Ausnahmen stets aus einer geraden Anzahl. Nach der Zahl der Pulse (4, 6 oder 8, selten auch mehr) kann man verschiedene Silbentypen unterscheiden. Die Silbenund Pausendauern sind bei einer vorgegebenen Temperatur wenig variabel (Abb. 3, 4, 5). Der „Werbewechselgesang” unterscheidet sich im zeitlichen Muster der Silben- und Pausendauern nicht vom Spontangesang. 2. Mit steigender Temperatur verkurzen sich sowohl die Dauern der verschiedenen Silbentypen als auch die Pausendauern nach einer Exponentialfunktion. Das Verhaltnis zwischen Silben- und Pausendauer bleibt dabei konstant (Abb. 6, 7, 8). 3. Das Lautschema (angeborener auslosender Mechanismus des Weibchens fur die Antwort auf den Gesang eines Mannchens) bleibt wahrend der Lebensdauer eines Weibchens konstant. Eine Lautattrappe aus getastetem Rauschen lost nur dann eine Antwort aus, wenn die Parameter Silben- und Pausendauer bestimmte, voneinander abhangige Werte annehmen: Mit steigender Silbendauer wird auch die am besten beantwortete Pause langer (Abb. 14). Tragt man die optimal beantwortete Pausendauer als Funktion der Silbendauer auf, so erhalt man annahernd eine Gerade (Abb. 15). Versdauer, Versabstand und Verszahl spielen beim Erkennen des Artgesanges nur eine untergeordnete Rolle, jedoch mus eine Mindestversdauer von etwa 1,2 s eingehalten werden (Abb. 18). Die Abstande zwischen den Pulsen durfen (unter den gegebenen Versuchsbedingungen) 1–2 ms nicht uberschreiten, soll das Muster seine Wirksamkeit nicht verlieren. Bei langeren Pulsen ist auch die tolerierte Pulspause groser (Abb. 19). 4. Das Lautschema ist temperaturabhangig. Bei niedrigerer Temperatur werden bei einer gegebenen Silbendauer langere Pausen maximal beantwortet und insgesamt langere Silben bevorzugt (Abb. 15, 20). 5. Das Lautschema eines Weibchens umfast bei einer Temperatur von 35 ° C nicht nur die Gesangsmuster von Mannchen derselben Temperatur, sondern die Silben-Pausen-Muster eines weiten Temperaturbereiches (Abb. 17, 21).

Gasphasenabscheidung im system TiSiC

Abstract: Zusammenfassung Die Gasphasenabscheidung im System TiSiC wurde mit dem Reaktions-system TiCl4(g) + SiCl4(g) + CCl4(g) + H2(ex) untersucht, ein vollstandiges Abscheidungsdiagramm (xa(s) = f(xi(g); xj(g))) fur 1200 °C und Normaldruck erstellt, die Morphologie und Verwachsungen bei zwei- und drei-phasigen Gleichgewichtsphasen und insbesondere die Eigenschaften des Komplexcarbids Ti3SiC2 studiert. Im Vergleich zu der Abscheidung binarer Phasen, die innerhalb bestimmter Konzentrationsstrecken (“Gasphasenbreiten”, Δxi(g)) abgeschieden werden, gelangen die ternaren Phasen (Ti3SiC2 oder Ti5Si3Cx) innerhalb diskreter Konzentrationsfelder (Δxi(g); Δxj(g)) zur Abscheidung. Ein Abscheidungsmodell wird vorgeschlagen.

The geostrophic drag coefficient and the ‘effective’ roughness length

Abstract: An ‘effective’ roughness length is defined for use over heterogeneous terrain as the roughness length which homogeneous terrain would have to give the correct surface stress over a given area. A method is suggested to compute geostrophic drag coefficient, wind-contour angle and surface heat flux, given this roughness length, latitude, geostrophic wind speed and insolation or ground-air temperature differences.

The effect of SO 3 (--) on the activity of ribulose-1,5-diphosphate carboxylase in isolated spinach chloroplasts.

Abstract: SO 3 -- inhibits the activity of ribulose-1,5-diphosphate carboxylase in isolated spinach chloroplasts. It shows a non-competitive inhibition pattern with respect to ribulose-1,5-diphosphate and Mg++ but a competitive one with respect to HCO 3 - . The K i -values are 14 mM SO 3 -- and 9.5 mM SO 3 - respectively for the non-competitive inhibition but only 3.0 mM SO 3 -- in the case of competitive inhibition with HCO 3 -- as a substrate. Thus it is concluded that the competitive inhibition type will predominate at low SO 3 -- and low internal CO2 concentrations.

The origin of Standard Old English and Æthelwold's school at Winchester

Abstract: ‘In literary culture’, Sir James Murray has said, ‘the Normans were about as far behind the people whom they conquered as the Romans were when they made themselves masters of Greece.’ Indeed when the Normans set foot on English soil Anglo-Saxon England was in possession not only of a remarkable literature but also of a highly developed written standard language, known and used in all regions of the country. Most of our Old English manuscripts were written in the late tenth century and in the eleventh in a form of English – although not always quite pure – which the grammarians call late West Saxon. This form of the language is by no means just a dialect, any more than its literature is merely the literary product of a dialect. This fact is first brought home to us when we examine the negative evidence – the rareness before the end of the tenth century of texts in dialects other than West Saxon and their almost complete absence after this time, a state of affairs for which various explanations might be found, historical factors among others. Considerably more important, however, is a positive criterion: texts in this late West Saxon were written and read in other parts of the country too, in Kent (Canterbury), in Mercia (Worcester) and indeed even in Northumbria (York). Moreover, texts which had originally been written in Anglian were transcribed into late West Saxon, as was a large part of Old English poetry. There can be no doubt: in our Old English texts of the eleventh century we are dealing with a standard literary language which, although based on a dialectal foundation, had extended its domain beyond the borders of this dialect.

Histamine release in man by propanidid and thiopentone: pharmacological effects and clinical consequences

Abstract: SUMMARY Using a new, highly sensitive and specific method for the determination of histamine in human plasma, it was shown that release of histamine followed injection of propanidid and thiopentone. Observations of gastric secretion, arterial pressure and pulse rate supported these findings. In normal persons the release of histamine had no special clinical significance. On the other hand, when anaphylactoid reactions occurred following propanidid injection histamine release was so massive as to explain the severe clinical signs and symptoms observed. In this study no reactions occurred following thiopentone injection. Although it seems likely that massive histamine release can occur during anaphylactoid reactions with this anaesthetic, we have no observations to confirm this. In one case it was shown that premedication with glucocorticoids and anti-histaminics and therapy with plasma substitutes could prevent the development of a severe reaction.

The position of short and long loops of Henle in the rat kidney.

Abstract: To determine the histotopographical relations of short and long loops of Henle in the rat kidney single short and long-looped nephrons were marked by microinjection with a silicone rubber and subsequently traced in histological serial sections. Short loops of Henle, derived from both supericial and midcortical nephrons, follow a similar course and possess similar histotopographical relations. In the medullary rays of the renal cortex and in the outer stripe of the outer medullary zone both limbs of short loops of Henle are lying together, near to the corresponding collecting duct. At the transition of outer and inner stripes the descending limbs turn towards the bundles and descend in the bundle periphery juxtaposed to venous vasa recta. After looping back at the junction of outer and inner zones they change position and ascend distant from the bundles in the vicinity of collecting ducts. The straight proximal portions of long-looped nephrons directly penetrate the outer stripe transversing this zone in tortuous course. In the inner stripe, the thin descending limbs of long loops of Henle descend distant from the bundles among the ascending thick limbs. In the inner medullary zone, neither the descending nor the ascending thin limbs have an exactly defined constant histotopographical position. The long loops ascend straight through the outer medullary zone, usually near to a vascular bundle, and reach the convoluted portion without transversing the medullary rays. The regularity of the histological pattern in the outer medullary zone suggests that the arrangement of the loops may influence their function, whereas in the inner zone the histotopographical position of the loop limbs does not appear to be a functionally important parameter.

Übergangsmetall‐Carben‐Komplexe, XLII. Synthese von Cyclopropanderivaten aus α.β‐ungesättigten Carbonsäureestern mit Hilfe von Übergangsmetall‐Carbonyl‐Carben‐Komplexen

Abstract: Phenyl(methoxy)carben-pentacarbonyl-chrom(0) (1) reagiert bei erhohter Temperatur mit trans-Zimtsaure-methylester (2), Fumar- (3) und Maleinsaure-diathylester (4) unter Ubertragung des Carben-Liganden stereospezifisch zu den entsprechenden Methoxy-phenyl-cyclopropancarbonsaureestern (6–8). Deren Konfiguration wird durch Analyse der 1H-NMR-Spektren bestimmt. Die IR- und Massenspektren der Verbindungen werden diskutiert. Die Umsetzungen der Phenyl(methoxy)carben-pentacarbonyl-Komplexe des Chroms(0) (1), Molybdans(0) (10) und Wolframs(0) (11) mit trans-Crotonsaure-methylester (5) und Maleinsaure-diathylester zeigen einem carbenoiden Ubergangszustand entsprechend eine Abhangigkeit des Produktverhaltnisses der Cyclopropan-Isomeren vom Ubergangsmetall an. Transition Metal Carbene Complexes, XLII. Synthesis of Cyclopropane Derivatives from α.β-Unsaturated Alkyl Carboxylates with the Aid of Transition Metal Carbonyl Carbene Complexes [Phenyl(methoxy)carbene]pentacarbonylchromium(0) (1) reacts at elevated temperature with trans-methyl cinnamate (2), diethyl fumarate (3) and diethyl maleate (4) stereospecifically to give the corresponding methyl and diethyl [methoxy(phenyl)cyclopropane]-carboxylates (6–8) by transfer of the carbene ligand. The configuration of the cyclopropane derivatives is determined by analysis of the 1H n.m.r. spectra. The i.r. and mass spectra of the cyclopropane compounds are discussed. The reactions of the [phenyl(methoxy)carbene]pentacarbonyl complexes of chromium(0) (1), molybdenum(0) (10) and tungsten(0) (11) with trans-methyl crotonate (5) and diethyl maleate indicate a dependence of the ratio of the cyclopropane isomers on the transition metal which is consistent with a carbenoid transition state.

Übergangsmetall-Carben-Komplexe, LI Synthese von Cyclopropanderivaten aus Vinyläthern mit Hilfe von Übergangsmetall-Carbonyl-Carben-Komplexen

Abstract: Pentacarbonyl[methoxy(phenyl)carben]chrom(0) (1) reagiert mit Athylvinylather (2) und Isobutylvinylather (3) uberwiegend zu α-Methoxystyrol (5). Demgegenuber liefert die Substitution des Carbenliganden durch Kohlenmonoxid unter Druck die entsprechenden Dialkoxycyclopropan-Derivate (7, 8). Ihre 1H-NMR-, IR- und Massenspektren werden diskutiert. Die Cycloadditionsreaktionen der Pentacarbonyl[methoxy(phenyl)carben]-Komplexe des Chroms(0) (1), Molybdans(0) (9) und Wolframs(0) (10) mit dem Vinylather 2 zeigen eine Abhangigkeit des Produktverhaltnisses der Cyclopropan-Isomeren vom Ubergangsmetall an. Transition Metal Carbene Complexes, LI Synthesis of Cyclopropane Derivatives from Vinyl Ethers with the Aid of Transition Metal Carbonyl Carbene Complexes Pentacarbonyl[methoxy(phenyl)carbene]chromium(0) (1) reacts with ethylvinyl ether (2) and isobutylvinyl ether (3) to give mainly α-methoxystyrene (5). In contrary the substitution of the carbene ligand by carbon monoxide under pressure yields the corresponding dialkoxycyclopropane derivatives (7, 8). Their 1H n.m.r., i.r. and mass spectra are discussed. The cycloaddition reactions of the pentacarbonyl[methoxy(phenyl)carbene] complexes of chromium(0) (1), molybdenum(0) (9), and tungsten(0) (10) with the vinyl ether 2 indicate a dependence of the ratio of the cyclopropane isomers on the transition metal.

Compound Slit Sense Organs on the Spider Leg: Mechanoreceptors Involved in Kinesthetic Orientation

Abstract: 1. The hunting spiderCupiennius salei Keys is able to direct its locomotion by making use of information about its own previous movement sequences (kinesthetic orientation). After a blinded spider is chased ca. 25 cm away from a prey-fly, it returns to the original capture site despite the preclusion of other possible orientation clues. The mean starting direction of such returns differs from the ideal return direction by only 2 ° (Fig. 4a, 5). Of all runs 95% are “successful” in that the animals approach the capture site as close as 5 cm (mean value) (Fig. 3). 2. Mechanical destruction of compound slit sense (“lyriform”) organs on femur and tibia of all legs results in disorientation of the spiders: more than 2/3 of their returns pass the capture site at a distance of more than 10 cm (Fig. 3, 4b). In addition, the mean angular deviation of starting directions increases significantly. The difference between the mean starting angles of the treated groups and the mean of intact animals, however, is significant only in some cases. 3. A special effort was made to evaluate not only thestarting directions and the “success” of a return path, but theentire return route, which is comprised of several path segments based upon each stopping and/or turning point. To this end a “walking error” en was determined for each segment (Fig. 8). For intact animals the error increases abruptly at the point nearest to the capture site. We therefore conclude that the spiders control also their walking distance kinesthetically. In the case of operated animals the mean “walking error” calculated from those segments lying before the “nearest point” increases by a factor of 4 to 5, as compared with intact spiders, whereas it remains about the sameat the “nearest point” itself (Fig. 9). 4. Small holes pierced into the leg cuticle near intact lyriform organs of otherwise intact “control animals” do not influence the success, starting angle, and walking errors of returns.

Lateral inhibition in an insect eye

Abstract: Intracellular light-evoked potentials were measured from both visual cells and secondary neurons (monopolar neurons type I) in the eye of Calliphora at varying angles of light-incidence. From these measurements and from the characteristic curves we obtained a relationship between the effective light intensity and the angle of incidence of the light stimulus for both cell types. These curves must be identical for the two cell types in the absence of a lateral information processing as a theoretical reflection shows. From the experimental results that the curve (effective light intensity versus light angle of incidence) of the monopolar neurons was considerably narrower as that of the visual cells, it was concluded that a lateral inhibition in the first optic ganglion of the fly retina exists. Although the information coding in the secondary neurons of the fly retina was completely different (graded potentials) from that of corresponding neurons in the Limulus eye (spikes), it appeared that the same principles of information processing existed in both instances.

Reliability Optimization of a Series-Parallel System

Abstract: A mathematical model is formulated for optimizing the reliability of a system subject to given linear constraints; the system has several stages in series; each stage has parallel redundancy to improve the reliability. Part I shows a new way to transform the model of constrained optimization to a saddle point problem by using Lagrange multipliers. Conditions are derived for maximizing the reliability function; Newton's method is used to solve the resulting multidimensional nonlinear algebraic equations. Further modifications are provided to avoid inverting the large Jacobian matrices; therefore this method is practical for large systems. Part II shows how to transform the model of constrained optimization to a multistage decision process and uses the Maximum principle to arrive at the optimal decision. This approach is easy to apply, formulate, and program. The solution can be obtained without fear of nonconvergence (very often experienced with earlier methods) besides providing considerable saving in computer time. Design alternatives can be easily considered.

THE LOCALIZATION OF ENDOGENOUS PEROXIDASE IN THE LACRIMAL GLAND OF THE RAT DURING POSTNATAL DEVELOPMENT : Electron Microscope Cytochemical and Biochemical Studies

Abstract: The distribution of endogenous peroxidase activity in the lacrimal gland of the rat during postnatal development was investigated by electron microscope cytochemistry Peroxidase activity is first found 6 hr after birth in only a few acinar cells At this stage, reaction product fills only localized segments of the scant rough endoplasmic reticulum and of the perinuclear cisternae. Peroxidase activity thus develops asynchronously in a given cell as well as in the secretory cell population as a whole 2 days after birth, all cisternae of the rough endoplasmic reticulum of a peroxidase-positive cell contain reaction product, but the majority of the acinar cells is still negative During the next days, the number of peroxidase-positive cells and the amount of the rough endoplasmic reticulum increase rapidly. By 15 days postparturition, all secretory cells are peroxidase-positive. Reaction product is then found in all cisternae of the rough endoplasmic reticulum including the perinuclear cisternae, in smooth surface vesicles located mainly between the rough endoplasmic reticulum and the Golgi stacks, in condensing vacuoles, and in all secretory granules The Golgi cisternae rarely contain reaction product In total homogenates and in fractions of glandular tissue of adult rats, peroxidatic and catalatic activities are demonstrable. The microsomal fractions and the postmicrosomal supernatants were used to separate peroxidase from catalase by precipitation with ammonium sulfate, and the following parameters were determined: substrate (H2O2-) optimum (∼ 2.0 x 10-4M), pH-optimum (pH 6 5), temperature-optimum (42°C), and the absorption maximum (415 nm before and 425 nm after addition of H2O2) The same parameters were obtained from lacrimal fluid peroxidase. Both peroxidase from lacrimal gland and that from lacrimal fluid are almost completely inhibited by 10-3M aminotriazole and are possibly identical enzymes. Peroxidase is secreted into lacrimal fluid, which does not contain catalase.

Effect of surface roughness on the total reflexion and transmission of slow neutrons

Abstract: The total reflexion of subthermal and thermal neutrons from rough surfaces is analyzed in the limits of small and large roughness dimensions as compared to the neutron wave length. The analysis shows that the scattering distribution from a submicroscopically rough surface is determined by the spectrum of the roughness, concentrating near the directions of regular reflexion and transmission unless the surface irregularities exhibit a long-range correlation. It is shown that submicroscopic surface roughness and macroscopic waviness are the primary sources of reflexion losses in guide tubes for ultracold and thermal neutrons, respectively. The present theory explains experimental values for neutron guide tube transmission.

Decomposition of Organometallic Complexes in the Mass Spectrometer

Abstract: The reliable interpretation of mass spectra for the determination of molecular constitutions requires systematic studies on the fragmentation behavior of classes of compounds, since the large number of kinetic and energy parameters that determine the decomposition of excited polyatomic ions makes ab-initio predictions of spectra almost impossible. In this progress report, a number of general rules for the decomposition of organometallic complexes upon electron impact are discussed; a classification into decomposition types is also presented, and is illustrated by selected examples.

Renal failure as the cause of death inTupaia belangeri exposed to persistent social stress

Abstract: 1. An adult male Tupaia belangeri was introduced to another male which was an experienced fighter. The latter immediately attacked the newcomer and subjugated him (Figs. 1 and 2). The two animals were subsequently separated, so that the subordinate animal could see the victor permanently, but could not be attacked by him. The fight and subjugation were repeated every 1-2 days, in order to maintain dominance relationships. Changes in physiological parameters were determined by sacrificing some of the tree-shrews at 2-16 days after the first subjugation, 80-100 minutes before the onset of daily activity. 2. After the first subjugation, subordinate animals lie still in a corner for more than 90 % of the daily activity-phase and follow the movements of the victors with their heads. The tail-hair is continuously raised, indicating persistent activation of the sympathetic nervous system. Subordinate animals eat as long as controls. 3. After 2-16 days, the skin-temperature of the subordinates abruptly falls from more than 35~ to less than 30~ within 24 hours. Cramps and paralysis appear in the extremities, the tree-shrews fall into coma and die. Wounds can be excluded as the cause of death. 4. The following physiological changes take place in the subordinate animals: a) The animals lose body weight in a linear fashion. The rate of weight-loss varies considerably between animals (Fig. 3). The more weight an animal loses daily, the more rapidly it dies (r ~ 0.89; Fig. 4). Death is not a result of inadequate energy-supply (resp. hypoglyeaemia). b) In subordinates, the glycogen content of the liver is significantly below that of controls (p~0.003; Table 1); but even dying animals may exhibit normal glycogen values. The glucose concentration of the blood is the same under both conditions (Table 1). c) The haemoglobin content of the blood decreases during stress exposure (r ~ 0.75; Fig. 5). The decrease is the more rapid, the more weight a subordinate animal loses daily (r~0.68). The decrease in haemoglobin concentration is primarily due to haemolysis, but erythropoiesis is also restricted (Table 2). d) The kidney weight decreases with continued stress; animals sacrificed more than 10 days after their first subjugation have kidneys approximately 17 % lighter than those of controls (p < 0.05; Fig. 8). e) During the course of stress, urea-N content of the blood increases (Fig. 6). The more rapidly the urea-N increases, the more rapid is the decrease in blood haemoglobin content ( r ~ 0.89). Subordinate animals can move around normally with values up to 150 mg urea-N/100 ml blood, and they look healthy. If the concentration rises above this level, symptoms of imminent death appear, and the animals die.

Mantle Plumes, Movement of the European Plate, and Polar Wandering

Abstract: The passage of lithospheric plates over thermal plumes or hotspots in the mantle is discussed with respect to the history of two igneous chains in the European plate.