showing 36 of ~574560 from 574555 documents
Patterns of variation in tail ornament size in birds
1988
In recent years several different kinds of sexual selection models have been developed, and tail ornaments in birds have frequently been used as an example of a sexually selected character where the models might apply. However, very little is known about intra- and interpopulation variation in ornament size. We have studied the elongated tail ornaments in four species of whydahs Vidua, the forktailed flycatcher Tyrannus savana and the Asian paradise flycatcher Terpsiphone paradisi. Ornaments were relatively longer in males with the longest tarsi (‘heterogony’ with positive allometry). Also, tail lengths were remarkably variable within each geographical area, the coefficient of variation (av…
Computation of Amplitudes in the Discretized Approach to String Field Theory
1988
An approach to Witten string field theory based on the discretization of the world sheet is adopted. We use it to calculate tree amplitudes with the formulation of the theory based on string functionals. The results are evaluated numerically and turn out to be very accurate, giving, for a string approximated by 600 points, values within 0.02% of the prediction of the dual model. The method opens a way to calculate amplitudes in string field theory using nonflat backgrounds as well as compactified dimensions.
Methods for determining actual evapotranspiration in plots
1988
International audience
Electronic structure of metal‐free phthalocyanine : A valence effective Hamiltonian theoretical study
1988
We present a valence effective Hamiltonian (VEH) nonempirical investigation of the electronic properties of metal‐free phthalocyanine. The valence one‐electron energy levels are related to those of the phthalocyanine components: benzene, pyrrole, and isoindole. From the electronic structure standpoint, phthalocyanine has to be viewed as formed by joining four benzene moieties to the central carbon–nitrogen ring rather than by combining four isoindole units through nitrogen bridges. Comparison of the VEH density‐of‐valence‐states curves with the experimental ultraviolet photoelectron spectroscopy (UPS) data is quantitatively excellent and allows for a complete interpretation of the experimen…
Appien et l'extermination des Sénons
1988
International audience
Determination of 5-nitrofurylacrylic acid in wines by high-performance liquid chromatography
1988
Silver Impregnation of Alzheimer's Neurofibrillary Changes Counterstained for Basophilic Material and Lipofuscin Pigment
1988
A method is described in which selective silver staining of Alzheimer's neurofibrillary changes is combined with staining of cell nuclei, Nissl material, and lipofuscin granules. Formalin fixed, paraffin embedded sections of human autopsy tissue are silver stained according to a method proposed by Gallyas. Lipofuscin is stained by crotonaldehyde fuchsin following performic acid oxidation. Nissl substance is visualized by either Darrow red or gallocyanin-chrome alum staining. Architectonic units showing the specific pathology and the neuronal types prone to develop the neurofibrillary changes can be recognized using this technique.
The phase composition of the passive layer on iron
1988
Phylloscopus borealoides Portenko — ein verkannter Laubsänger der Ost-Paläarktis
1988
Ussuri-Laubsanger (Phylloscopus tenellipes) vom ostsibirischen Festland und von den Inseln des Japanischen Meeres (Sachalin, S-Kurilen, Hokkaido, Hondo) sind morphologisch kaum unterscheidbar, in der Stimme jedoch auserst verschieden. Die Festlandsform besitzt einen Heuschrecken-ahnlichen Schwirrer, die Inselform eine Serie heller Pfiffe. Da auch die Rufe betroffen sind, wird auf wenigstens partiell genetische Basis der Unterschiede geschlossen. Fur beide Formen kommt nach der Struktur der Gesange Anpassung an stark gerauschbelastete Biotope in Frage, z. B. den Uferbereich von Gebirgsbachen. Obwohl der Sympatrie-Nachweis bisher aussteht, sind die Argumente gravierend, beide Formen als eigen…
Artificial intelligence techniques for cancer treatment planning
1988
An artificial intelligence system, NEWCHEM, for the development of new oncology therapies is described. This system takes into account the most recent advances in molecular and cellular biology and in cell-drug interaction, and aims to guide experimentation in the design of new optimal protocols. Further work is being carried out, aimed to embody in the system all the basic knowledge of biology, physiopathology and pharmacology, to reason qualitatively from first principles so as to be able to suggest cancer therapies.
An immune system model in discrete time based on the analogy with the central nervous system
1988
Jerne's model for the immune system formulated in terms of a neural network recently proposed by Weisbuch and Atlan is generalized to interactions with continuous coupling coefficients. It is shown that even the extended model can be solved analytically without the aid of computer simulations and exhibits one additional attractor, which corresponds to a configuration with high concentrations of active killer cells eventually causing death of the organism.
A new species of Echium for the Spanish Flora
1988
PERIS, J. B., FIGUEROLA, R. & STOBING, G., 1988. A new species of Echium for the Spanish Flora. A description is given of a new species of the genus Echiurn L. for the Spanish Flora.
Heat capacities, volumes and solubilities of pentanol in aqueous alkyltrimethylammonium bromides
1988
Apparent molar heat capacities and volumes of pentanol, 0.05m in decyl-, tetradecyl- and hexadecyltrimethylammonium bromides micellar solutions, were measured at 25°C. They were assumed to approach the standard infinite dilution values and rationalized by means of previously reported equations following which the distribution constant between the aqueous and the micellar phase, heat capacity, and volume of pentanol in both phases are simultaneously derived. The present results show that the volume of the micellar core does not seem to have a significant effect on the apparent molar volume and heat capacity of pentanol in the micellar phase and on the free energy of transfer of pentanol from…
The suppressive effects of recombinant human tumor necrosis factor‐alpha on normal and malignant myelopoiesis: Synergism with interferon‐gamma
1988
The modulation of growth of normal and leukemic myeloid progenitor cells in soft agar cultures by recombinant human tumor necrosis factor-alpha (TNF alpha) and recombinant human interferon-gamma (IFN gamma) was investigated. TNF alpha inhibited colony formation of all colony types representing different maturational stages of normal progenitor cells committed to the myeloid lineage with different orders of sensitivity. Blast-type colonies derived from patients with acute myelogenous leukemia were more sensitive to TNF alpha inhibition than progenitor cells purified from normal bone marrow or bone marrow from patients with stable-phase chronic myelogenous leukemia. The response of most colon…
Short- and long-latency muscarinic inhibition of noradrenaline release from rabbit atria induced by vagal stimulation.
1988
1. The influence of the time interval between vagal and sympathetic nerve stimuli on the magnitude of muscarinic inhibition of noradrenaline release was studied in the isolated perfused rabbit atria preparation. The transmitter stores were labelled with [14C]choline and [3H]noradrenaline. 2. The right cardiac postganglionic sympathetic nerves were stimulated at 3 Hz for 3 min three times at intervals of 10 min. The [3H]noradrenaline outflow evoked by the second stimulation equalled the averaged means of the log values of amine outflows evoked by the first and third stimulations. 3. During the second sympathetic stimulation the right vagus nerve was stimulated (3 Hz, 3 min) in such a way tha…
Muscarinic inhibition of [3H]-noradrenaline release on rabbit iris in vitro: effects of stimulation conditions on intrinsic activity of methacholine …
1988
1. Rabbit isolated irides were loaded with [3H]-noradrenaline and superfused with Tyrode solution. The inhibition by the muscarinic agonists (+/-)-methacholine and pilocarpine of the [3H]-noradrenaline overflow into the superfusate evoked by field stimulation (pulses of 1 ms duration, 75 mA) was measured as an index of activation of presynaptic muscarinic receptors. 2. The fractional rate of release per pulse during the first stimulation period (S1) was low with 360 pulses at 3 Hz, intermediate with 360 pulses at 10 Hz and high with 1200 pulses at 10 Hz. Upon repetitive stimulation (7 periods at 20 min intervals), the fractional rates of release per pulse during S7 no longer differed, sugge…
Non-stationary spectral moments of base excited MDOF systems
1988
The paper deals with the evaluation of non-stationary spectral moments of multi-degree-of-freedom (MDOF) line systems subjected to seismic excitations. The spectral moments of the response are evaluated in incremental form solution by means of an unconditionally stable step-by-step procedure. As an application, the statistics of the largest peak of the response are also evaluated.
Determination of molecular mass, Stokes' radius, frictional coefficient and isomer-type of non-denatured proteins by time-dependent pore gradient gel…
1988
Molecular mass, Stoke's radius, frictional coefficient and isomer-type of non-denatured proteins can be obtained by time-dependent gradient gel electrophoresis by evaluating the resulting data using a two-step mathematical procedure. Provided a histochemical staining procedure is available to locate the position of an enzyme in the gel, crude cell extracts can be used for estimating their molecular size properties. The computation of molecular properties of non-denatured proteins is demonstrated for isozymes of aspartate aminotransferase (EC 2.6.1.1), peroxidase (EC 1.11.1.42) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) from current-year needles of spruce. The resulting data as well…
A? * algebra of pseudodifferential operators on noncompact manifolds
1988
On montre qu'une classe d'operateurs pseudodifferentiels d'ordre zero a la propriete d'invariance spectrale
A new species of Crepidostomum (Allocreadiidae: Digenea) from northeastern Finland, with comments on its possible origin
1988
Crepidostomum wikgreni n. sp. is described from the gall-bladder and intestine of the whitefish Coregonus acronius in Lake Yli-Kitka in NE Finland. It is morphologically similar to Crepidostomum farionis, with which it occurs sympatrically and sometimes concurrently; but it differs in that the eggs are much larger, i.e. 96±6.5 μm mean-length, as opposed to 71±4.7 μm mean-length for C. farionis in the same host and locality. It is suggested that the new species has arisen from C. farionis after deglaciation and since c. 8,400 BP, at which time the waters of the Lake Kitka System were isolated from those in the rest of Finland and flowed eastwards into the White Sea Basin. The isolation of th…
The University of Valencia’s computerized word pool
1988
This paper presents the University of Valencia’s computerized word pool. This is a database that includes 16,109 Spanish words, together with 11 psychological variables for limited groups of items. The purpose behind the creation of this database was to have available a large quantity of verbal stimuli in a well-controlled system, ready for automatic selection. The description includes a summary of statistics on each of the 11 psychological variables, together with a correlational and factor analysis of them. This statistical analysis produces results close to those obtained for equivalent English material.
Proton distortion effects and meson exchange current contributions in the (e,e′p) reaction
1988
It is demonstrated that proton distortion effects could explain the relative enhancement of transverse to longitudinal response in the recent ($e,{e}^{\ensuremath{'}}p$) reactions on $^{12}\mathrm{C}$. The spin-orbit field is essential to bring about this enhancement. The role of the convection current is pointed out. Favorable contributions from pion-pair and isobar-excitation currents are also found.
On almost sure convergence of amarts and martingales without the Radon-Nikodym property
1988
It is shown here that for any Banach spaceE-valued amart (X n) of classB, almost sure convergence off(Xn) tof(X) for eachf in a total subset ofE * implies scalar convergence toX.
Optimization of the domain in elliptic variational inequalities
1988
This paper is concerned with a nonsmooth shape optimization problem for the Signorini unilateral boundary-value problem. The necessary optimality conditions are derived. The results of computations are presented.
Coordination properties of imino(2-pyridyl)methylpalladium(II) compounds. Preparation and thermal rearrangement of binuclear adducts with palladium(I…
1988
Abstract The imino(2-pyridyl)methylpalladium(II) compound py-2-C(R′)NR (R = C 6 H 4 OMe-p, R′ = trans-PdCl(PPh 3 ) 2 ) reacts with [PdCl 2 (CH 2 CHPh)] 2 , [PdCl 2 - (NCMe) 2 ], and K[PtCl 3 (CH 2 CH 2 )] to give binuclear complexes [MCl 2 {py-2- C(R′)NR}] (M = Pd, Pt), in which the α-diimino group acts as a chelating bidentate ligand. In hot 1,2-dichloroethane, these complexes undergo a PPh 3 and chloride ligand exchange at rates which depend markedly on the metal M (Pd ⪢ Pt), to yield the new derivatives [MCl(PPh 3 ){py-2-C(cis-PdCl 2 (PPh 3 ))NR}]. The ligand exchange is followed by a much slower decomposition to [MCl 2 (PPh 3 ) 2 ]. Labile intermediates of the same type, [MCl(PPh …
false
1988
An apparatus for turbidimetric measurements of demixing temperatures under shear flow is presented, and the results of experiments with trans-decahydronaphthalene/polystyrene (TD/PS) solutions, investigating molecular weights ranging from 100 kg/mol to 1770 kg/mol, are compared with viscometric data. It is found that the sign and magnitude of shear effects depend on molecular weight (Mw), polymer concentration (c2), and shear rate (). For the first time, it was possible to study a solution which exhibits shear dissolution at low shear rates but shear demixing at high shear rates.
false
1988
Poly(n-decyl methacrylate), a statistical copolymer of ethylene and propylene, and a diblock copolymer of styrene and hydrogenated butadiene were studied as representatives of various kinds of viscosity-index (VI) improvers. Essomarcol 52 and AF 1 from Schindler served as base-oils, toluene and 1-phenyl dodecane were also studied. By means of viscosity measurements in the temperature interval from 37.8 to 98.9°C up to a concentration of typically 1 wt.-% polymer, the viscosity indices of the different systems and the corresponding intrinsic viscosities, Huggins coefficients, and activation energies of flow, E≠, were determined. The discussion of the obtained experimental material demonstrat…
Regioselective proton-catalyzed diarylmethylation of indoles with 9H-xanthydrol, dibenzosuberenol, and bis[4-dimethylaminophenyl]methanol
1988
3-Isopropylindole (4) is xanthenylated both at N-1 (stereocontrolled major reaction), C-2, and on the phenyl nucleus of the indole skeleton by xanthydrol (1). Other carbinols such as dibenzosuberenol (2) and bis[4-dimethylaminophenyl]methanol (3) with lower electrophilic SN1 activities than 1 do not react with 4 but do react very selectively with simple methylindoles to form diarylmethylated derivatives.
Zur Wirkung von Muskelrelaxantien auf den intraokularen Druck
1988
Since general anesthesia is being used increasingly in ophthalmic surgery, the effects of anesthetic drugs on intraocular pressure (IOP) have to be considered. Competitive neuromuscular blocking drugs either do not affect IOP or produce a slight decrease. Depolarizing muscle relaxants increase IOP. This effect, which is pronounced with succinylcholine, cannot be reliably prevented by any concomitant medication. The new competitive relaxants atracurium and vecuronium provide stable conditions with respect to IOP and systemic circulation, combined with fast onset and intermediate duration of action.
Effects of Intravenous Corticotropin-Releasing Hormone upon Sleep-Related Growth Hormone Surge and Sleep EEG in Man
1988
Corticotropin-releasing hormone (CRH) plays a key role in coordinating neuroendocrine, metabolic and behavioral responses in stress and affective disorders. To further investigate the effects of enhanced pituitary-adrenocortical activity upon sleep-related phenomena we administered four intravenous injections of 50 micrograms human (h)-CRH or saline to 11 normal males at 10 p.m., 11 p.m., 12 p.m. and 1 a.m. and measured plasma levels of cortisol and growth hormone (GH) as well as sleep EEG recordings throughout the night. Treatment with h-CRH resulted in a significant increase of mean (+/- SEM) cortisol secretion between 11 p.m. and 3 a.m. (h-CRH: 100.6 +/- 9.5 ng/ml; saline: 39.0 +/- 1.5 n…
Gamow-Teller decay ofZn80: Shell structure and astrophysical implications
1988
Gamow-Teller \ensuremath{\beta} decay of $^{80}\mathrm{Zn}$ to levels in $^{80}\mathrm{Ga}$ has been calculated from a random-phase-approximation shell model with Nilsson model wave functions. The predicted features are compared to existing experimental results. Gross \ensuremath{\beta}-decay properties as well as quasiparticle structure indicate shape coexistence for $^{80}\mathrm{Ga}$. This result implies a rather rapid weakening of the shell strength far from \ensuremath{\beta} stability above $_{28}^{78}\mathrm{Ni}_{50}$. The nuclear properties of $^{80}\mathrm{Zn}$ as an astrophysical ``waiting-point'' nucleus suggest that the r-process scenario which is responsible for the solar r abu…
Different metabolic behavior of long-chain n-3 polyunsaturated fatty acids in human platelets.
1988
Abstract Whereas numerous studies deal with the effects and metabolism of eicosapentaenoic acid (20:5( n −3)) in platelets, very few concern docosahexaenoic acid (22:6( n −3)), although both acids are consumed in equal amounts from most fish fat. The present paper reports the modulation of 22:6( n −3) oxygenation as well as that of endogenous arachidonic acid (20:4( n −6)) in 22:6( n −3)-rich platelets. Like the oxygenation of 20:5( n −3), the lipoxygenation of 22:6( n −3) occurred at a low level when incubated alone, but was markedly increased in the presence of 20:4( n −6), suggesting a similar peroxide tone dependency. 20:5( n −3) could not replace 20:4( n −6) in the increasing 22:6( n −…
Zum Flügelschwirren des Mikado-Fasans (Syrmaticus mikado)
1988
Flugelschwirren zeigen Mikado-♂ das ganze Jahr uber. Es stellt also keine eigentliche Balzleistung der ♂ dar. Einige Verhaltensweisen deuten zumindest bei den ♂ auf eine territoriale Funktion hin. Zum Schwirren werden haufig Stellen bevorzugt, die hoher als ihre Umgebung liegen. Auch Mikado-♀ fuhren Flugelschwirren wahrend des ganzen Jahres aus. Eine deutlich erkennbare Vorbereitungsphase tritt bei ihnen aber nur selten auf. Junge Mikado-Fasanen beider Geschlechter zeigen Flugelschwirren ab der 6. Lebenswoche. Die adulten ♂ schwirren signifikant haufiger und langer als die ♀, wobei die Haufigkeit sowohl im Jahres- als auch im Tagesverlauf zwei Maxima zeigt; im Tagesverlauf allerdings nur be…
Vibrational dephasing of νs(OH) in 2,6-dichloro-4-nitrophenol
1988
Abstract A detailed analysis of the infrared bandshape of ν s (OH) in intramolecularly hydrogen-bonded 2,6-dichloro-4-nitrophenol in a series of solvents is presented. A distinct dependence of the bandshape and relaxation parameters on the polarity of solvent molecules has been found. The band shifts to lower wavenumbers, broadens and becomes more Gaussian with increasing solvent polarity; correspondingly, the correlation function decays faster and the correlation time decreases. The results are compared with those of previously studied systems. Factors determing the bandshape are discussed.
false
1988
Deviations in the determination of the unperturbed dimensions of polymers arising in ternary polymer systems (solvent (1)/solvent (2)/polymer) can be explained by the inaccurate use of an interaction parameter independent of polymer molecular weight. On this basis, a new formalism for the calculation of the second virial coefficient from intrinsic viscosity is proposed. This formalism was tested (and compared with well established formalisms) for all ternary polymer systems with simultaneous intrinsic viscosity and second virial coefficient data in the literature.
false
1988
Phase diagrams were calculated for flowing solutions of polystyrene in trans-decahydronaphthalene assuming that the energy (Es) stored in the sheared state has to be added to the Gibbs energy of mixing; Es is computed from viscometric data (flow curves). The resulting phase diagrams exhibit two maxima in most of the cases instead of only one for the stagnant solutions. A comparison with experimental data (Part 1) shows that the calculated demixing behaviour agrees well for moderate shear rates and concentrations of the polymer. Deviations in the semidilute region, particularly for higher values, are a consequence of the fact that so far no reliable theoretical relation has been given for th…