Force-Time Characteristics and Running Velocity of Male Sprinters during the Acceleration Phase of Sprinting

1988

Abstract In an effort to investigate the force-time characteristics during the acceleration phase of the sprint start, eight male sprinters were used as subjects. Runs up to 3 m were analyzed from film, and force-time parameters were measured on a force platform. In a starting stance the reaction time of the group was .118 ± .016 s and the force production lasted .342 ± .022 s. The maximal resultant force at the moment of maximal horizontal force was 19.3 ± 2.2 N x kg1, and the direction of the force was 32 ± 7°. In the very last instant before leaving the blocks the velocity of the center of gravity was 3.46 ± .32 m x s−1. In the first contact after leaving the blocks there was a braking p…

On shakedown of elastic plastic solids

1988

Making reference to elastic perfectly plastic solids subjected to cyclic loads, the problem of the shakedown load factor is considered and the relevant Euler-Lagrange equations are discussed. It is proved that the solution to these equations describes the gradient, with respect to the load multiplier, of the steady-state response of the solid body to the cyclic loads at the shakedown limit, and that it thus enables one to predict the nature of the impending collapse. These results are then extended to the more general case of loads varying within a given load domain.

Adrenoceptor-mediated changes of action potential and force of contraction in human isolated ventricular heart muscle.

1988

Abstract 1. The effects of alpha-adrenoceptor stimulation on the action potential and force of contraction were investigated in human isolated ventricular heart muscle and compared with those of beta-adrenoceptor stimulation. 2. The maximal stimulation by isoprenaline of beta-adrenoceptors produced large changes in the force of contraction, which were accompanied by moderate increases in the height of the action potential. The maximal inotropic effect produced by stimulation of alpha-adrenoceptors with phenylephrine, in the presence of propranolol (1 mumol 1(-1)) was much smaller (about 10% of that seen in response to beta-adrenoceptor stimulation), and no significant changes of the action …

Soil degradation and its impact on desertification: A research design for Mediterranean environments

1988

Summary Much is said but little is known of the processes and linkages of soil degradation with desertification. With particular emphasis on South-East Spain, a research design is proposed to characterize the processes, their dynamics and effect on productivity. Through detailed monitoring of plot experiments at three slope positions, changes in soil physical and chemical parameters and analyses of runoff and eroded sediments will be related to induced destruction of the vegetation. Knowing the cause and process will lead to the identification of management techniques that may protect vulnerable Mediterranean environments.

Untersuchungen zur Konfigurationsstabilität von Enolaten aus β‐Ketocarbonsäureestern

1988

Z- und E-Enole von β-Ketocarbonsaurederivaten 1a–c werden vollstandig und irreversibel deprotoniert, wobei unter Konfigurationserhalt (kinetische Kontrolle) die Enolate 2a–c entstehen. Abhangig von Gegenionen (Li, Na, K), Medium (THF, HMPT) und Temperatur kann anschliesend eine Z/E-Aquilibrierung eintreten. Auf dieser Basis last sich die Synthese von Enolethern und Enolestern auf die gewunschte Konfiguration hinsteuern. Investigations on the Stability of the Configuration of Enolates from β-ketocarboxylic Acid Esters Z- and E-enoles of β-ketocarboxylic acid esters 1a–c are completely and irreversibly deprotonated yielding the enolates 2a–c under retention of the configuration (kinetic contr…

Der Schädel und Schultergürtel vonParamblypterus gelberti (Actinopterygii) und seine Verwandtschaft mit den Paramblypteriformes und Redfieldiiformes

1988

Das Schadelskelett und der Schultergurtel vonParamblypterus gelberti (Goldfuss, 1847) werden beschrieben. Die Gultigkeit der Gattung Paramblypterus wird in Frage gestellt. BeiP. gelberti konnten erstmals fur diese Gruppe grose Teile der Gaumenknochen beschrieben werden (Parasphenoid, Ento- und Ectopterygoid, Dermometapterygoid und Dermopalatina). Die Paramblypteriformes kommen nicht als Vorlaufer der Redfieldiiformes (sensu Schaeffer 1984) in Frage, weil das Pramaxilloantoarbitale bei der gesamten Gruppe fehlt.

Constitutive equations for no-tension materials

1988

For a material which is incapable of sustaining tensile stresses (no-tension material, NTM), the local stability postulate is utilized in order to derive the appropriate equations which relate, within general 3D situations, cracking strain states and stress states to each other. Several alternative forms of these equations are discussed, either in terms of stress and strain components, or in terms of stress and strain invariants. The results obtained improve known results regarding the NTM's.

Abstracts — Second Symposium on Upper Paleolithic

1988

The effect of balloon dilatation on post-stenotic myocardial perfusion before and after stimulation of coronary flow reserve: evaluation by the densi…

1988

From densitometric evaluation of digital subtraction cineangiocardiograms the parameter 'Mean Rise Time' (MRT), defined as the time from the onset of local myocardial contrast medium opacification to the point of maximal opacification can be derived; this parameter revealed a close correlation with the results on myocardial perfusion obtained by Thallium-201 scintigraphy. A prolonged 'Mean Rise Time' was indicative of an impairment of myocardial perfusion. We have developed a heart-phase gated real-time digitization procedure and computer-supported method for the densitometric estimation of the MRT to obtain information about the effect of coronary balloon dilatation on myocardial perfusion…

An optimal bound for embedding linear spaces into projective planes

1988

Abstract Linear spaces with υ >n 2 − 1 2 n + 1 points, b⩽n2 + n + 1 lines and not constant point degree are classified. It turns out that there is essentially one class of such linear spaces which are not near pencils and which can not be embedded into any projective plane of order n.

A study of caudate inhibition on an epileptic focus in the cat hippocampus

1988

The mechanisms whereby the caudate nucleus modifies hippocampal spiking activity have been studied. Epileptiform activity was induced in the cat hippocampus by topical application of sodium penicillin in different concentrations. The frequency of induced spikes appeared to be directly correlated to the two doses of epileptogenic agent. The inhibitory effect of 10 Hz caudate stimulation on spike frequency was present even when stimulation lasted for 180 s. Likewise 25 Hz caudate stimulation brought about an inhibition which was maintained by stimulus trains lasting up to 90 s, while the degree of inhibition was reduced by trains of longer duration (120, 150 and 180 s); similar results were a…

Acid stress in respect to calcium and magnesium concentrations in the plasma of perch during maturation and spawning

1988

Plasma calcium and magnesium concentrations in perch,Perca fluviatilis, were monitored in an acid lake, Lake Iso Tenhetty (pH ∼5, Al concentrations 0.3–0.5 mg l-1) compared with a nearby reference lake, Lake Paijanne, in Southern Finland. The effect of acid stress could be noticed as 1/3 lower fecundity of perch in the acid lake. Plasma Ca concentrations were temporarily lower in the middle of the winter in the fish of the acid lake, and in April–May samples the situation was opposite. Plasma Mg concentration was also lower in the perch from the acid lake in midwinter months, when compared with the double as high values (∼3 mmol l-1) from the reference lake. Elevated level of plasma Mg have…

Synthesis of oligomeric chains with 9,10‐dihydroanthracene units by carbanion alkylation

1988

Deprotonation of 9,10-dihydroanthracene (2) affords the monoanion 6 which is subjected to alkylation reactions with mono and bifunctional electrophiles. Crucial intermediates in syntheses using 6 are 9-(3-bromopropyl)-9,10-dihydroanthracene (7) and 1,3-bis(9,10-dihydro-9-anthryl)propane (9) since they provide access to linear oligomers in which 9,10-dihydroanthracene units are linked by trimethylene groups. The alkylation processes of these species can be extended to the structurally related polymer 4. The regio- and stereoselectivity of the alkylation reactions are investigated by 1H- and 13C-NMR spectroscopy. Oligomere Ketten mit 9,10-Dihydroanthracen-Einheiten durch Carbanionalkylierung …

Dipole Moments and the Direction of the Transition Dipole Moment of Some Intramolecular Exciplexes

1988

The dipole moments of some intramolecular exciplex systems have been determined from the effect of an electric field on their fluorescence and are compared to those estimated from solvent shift measurements. The charge transfer between the donor and acceptor subunits is between 0.6 and 0.9 of a full charge transfer. The face-to-face type exciplexes show considerable deviations from the general behaviour what might be due to some admixture of locally excited configurations to the exciplex wave function, in this way reducing the dipole moment values and changing the direction of the transition dipole moment.

Onset of deformation in neutron-rich krypton isotopes

1988

Beta-decay properties of neutron-rich35Br isotopes confirm the predicted smooth onset of quadrupole deformation for Z<37 already below N=60. The observed increase of the energy of the first 2+ state in the N=56 nucleus92Kr may indicate octupole softness.

false

1988

Terminaison d'un polystyrene lineaire telechelique avec des anions aux deux extremites a l'aide d'un agent de terminaison bifonctionnel et une haute dilution

Reactivation of chronic type B hepatitis: the effect on expression of serum HBV-DNA and pre-S encoded proteins.

1988

Hepatitis B markers were studied in seven patients with reactivated liver disease. Reactivation of chronic type B hepatitis, as indicated by the reappearance of hepatitis B e antigen (HBeAg) in the serum, was characterised by the appearance of hepatitis B virus-DNA (HBV-DNA) in the serum. The expression of pre-S 1 encoded protein remained unchanged in five of seven patients, and poly-HSA as a marker for pre-S 2 encoded protein remained detectable in six of seven patients before and after reactivation of chronic hepatitis. The level of serum HBV-DNA correlated well with the level of liver enzymes, which rose from normal to various levels after reactivation of the liver disease. The data sugg…

Short notes: Some Properties of the Rotation Lattice of Binary Trees

1988

Electronic aspects of the hydride transfer mechanism. III. Ab-initio analytical gradient studies of the cyclopropenyl-cation/LiH with 4-31G and 3-21+…

1988

Abstract Hydride transfer reaction have been studied in sections of the energy hypersurface of cyclopropenyl cation and lithium hydride at 4-31G and 3-21+G basis set levels. The diffuse component has enforced the idea of an hydride-ion as being the particle transferred in the ground electronic state. Calculations on the first triplet state suggest a transfer mechanism mediated by one-electron followed by an hydrogen atom transfer. The change of basis set does not affect structural and energetics aspects of the reacting system except for the transferred particle, where, for some molecular complexes, the electronic distribution can be described as a hydride ion cementing two electron defficie…

La utilizacion del tiempo de los estudiantes

1988

Référence interne : 88072

Cyclic fatty acid monomers : synthesis and characterization of methyl w-(2-alkylcyclopentyl) alkenoates and alkanoates

1988

Abstract Some 1,2-disubstituted cyclopentanes were synthesized. These were methyl 9-(2-butyl-cyclopentyl)-8-nonenoate, methyl 7-(2-hexyl-cyclopentyl)-6-heptenoate and methyl 5-(2-octyl-cyclopentyl)-4-pentenoate and their corresponding alkanoates. The synthesis involved a Michael addition of alkylmagnesium bromide to an unsaturated cyclic ester. The resulting cis and trans ethyl 2-alkylcyclopentane carboxylate were further converted to the alcohols then to the aldehydes. The aldehydes were condensed with the ylide derived from the (ω-carboxyalkyl)-triphenylphosphonium bromide and methylsulfinylmethide in DMSO to give unsaturated C18 cyclic fatty acid monomers. These cyclic fatty acids were f…

UNA RARA COMPLICANZA DELLA DERIVAZIONE VENTRICOLO-PERITONEALE. La Perforazione del Colon

1988

Gli Autori descrivono un caso di perforazione del colon, cisti peritoneale e peritonite saccata in una paziente portatrice di Shunt Ventricolo-Peritoneale.

Synthesis, electrochemistry, and spectroelectrochemistry of (P)Ge(Fc)2 and (P)Ge(C6H5)(Fc): first example of metal-carbon-.sigma.-bonded porphyrins w…

1988

The hydration enthalpies of Md3+ and Lr3+

1988

Lawrencium (3-min 260Lr) and lighter actinides were produced in the bombardment of a 249Bk target with 18O ions and loaded onto a cation exchange column in 0.05 M α-hydroxyisobutyrate solution at pH=4.85, together with the radioactive lanthanide tracers 166Ho, 171Er and 171Tm. In elutions with 0.12 M α=hydroxyisobutyrate solution (pH=4.85), trivalent Lr was eluted exactly together with the Er tracer and Md was eluted close to Ho. Lr elutes much later than expected based on the known elution positions of the lighter actinides and the expected analogy to the elution positions of the homologous lanthanides. From the measured elution positions, ionic radii were calculated for Lr3+ and Md3+. Sem…

Sex-related Differences in Disposition and Response to Phenprocoumon in Rats

1988

Abstract The pharmacokinetics and the pharmacological response to phenprocoumon have been studied in female and male inbred Lewis-Wistar rats. A significantly lower clearance was found in female than in male rats (7.9 ± 1.4 vs 24.5 ± 2.5 mL h−1 kg−1, respectively; t = 15.09, P &amp;lt; 0.001) as well as a lower apparent volume of distribution (288 ± 46 vs 617 ± 105 mL kg−1; t = 7.58, P &amp;lt; 0.001) and a longer half-life (25.5 ± 3.4 vs 17.5 ± 1.8 h; t = 5.16, P &amp;lt; 0.001). The binding of phenprocoumon was higher in female than in male rats (fu: 0.0096 ± 0.0008 vs 0.0124 ± 0.0007, respectively; t = 6.66, P &amp;lt; 0.001). The total (C) as well as the unbound concentration (Cu) neede…

'Anestheticography': on-line monitoring and documentation of inhalational anesthesia.

1988

The safe practice of inhalational anesthesia requires control over the amount of volatile anesthetic delivered to the patient. With minimal fresh gas flow this is facilitated by continuous monitoring and recording of the agent's concentration ('Anestheticography'). Alterations brought about by routine clinical maneuvers become visible. We recorded the course of the inspiratory and expiratory concentration of volatile anesthetic (Isoflurane) by infrared absorption and a trend recorder. Changing the carrier gas composition during high flow from 75% to 25% nitrous oxide in oxygen resulted in a 10% increase of the inspiratory isoflurane concentration. Activating the oxygen bypass or exchanging …

Responses of serum androgenic-anabolic and catabolic hormones to prolonged strength training.

1988

Endocrine and neuromuscular effects of prolonged strength training were investigated in 21 strength-trained male subjects during the course of a 24-week progressive strength training and during a subsequent detraining period of 12 weeks. Maximal isometric leg extensor force increased by 19% (P less than 0.001) during the first 20 weeks, followed by a plateau during the 4 latest weeks of training. During the course of the training period, no systematic change was found in serum testosterone concentrations, but there was a decreasing tendency in the concentrations of free testosterone (NS), 17-OH-progesterone (NS), androstenedione (P less than 0.05), dehydroepiandrosterone (P less than 0.05),…

Studies on effects of tamoxifen (ICI 46474) on agonistic encounters between pairs of intact mice.

1988

The anti-estrogen tamoxifen (Tam), which has been shown to dramatically suppress offensive behavior in male rats without markedly influencing other aspects of the social encounter, was tested for its effectiveness in mice. TO strain albino mice were given control injections or 50 or 100 micrograms of Tam for 4 or 8 days. Subsequently, mice were tested in pairs (for a particular dose and treatment duration) in which both animals received Tam, one animal received Tam and one saline, or both animals received saline control injections. Ten-minute videotaped encounters were analyzed in terms of total times allocated to nonsocial investigation, social investigation, offense, defense, sexual activ…

Collective behavior ofMbosonic modes interacting with a single two-level atom

1988

The Hamiltonian describing, without the rotating-wave approximation (RWA), the linear interaction between M bosonic modes with an Einstein spectrum and a single two-level atom is exactly and canonically transformed introducing M suitable collective independent field modes, in such a way that only one among them is coupled to the atom. Some physical consequences of this fact are analyzed and, in particular, the existence of radiation-trapping phenomena together with the possibility of atomic absorption suppression is established. The applicability of the RWA to this system is discussed and the importance of the effective-field statistics for the time evolution of the system is pointed out.

Nuclear orientation of radon isotopes by spin exchange optical pumping

1988

This paper reports the first demonstration of nuclear orientation of radon atoms. The method employed was spin exchange with potassium atoms polarized by optical pumping. The radon isotopes were produced at the ISOLDE isotope separator of CERN. The nuclear alignment of /sup 209/Rn and /sup 223/Rn has been measured by observation of ..gamma..-ray anisotropies and the magnetic dipole moment for /sup 209/Rn has been measured by the nuclear-magnetic-resonance method to be chemically bond..mu..chemically bond = 0.838 81(39)..mu../sub N/.

QCD duality analysis of B0-B0 mixing

1988

5 páginas, 4 figuras.-- CERN-TH-4951-88

Synthesis of peptides with α,β-dehydroamino acids, VI. Synthesis ofN-benzyloxycarbonyl andN-trifluoroacetyl dipeptides of α,β-dehydro-butyrine, -vali…

1988

Condensation of Z- and TFA-amino acid amides with 2-oxo-acids, namely butanoic, 3-methylbutanoic, 4-methylpentanoic, and (3RS)-3-methylpentanoic acid, yields (in the presence of p-toluenesulfonic acid as a catalyst) Z- and TFA-dipeptides with C-terminal ΔAbu2) (1–4), ΔVal (5–8), ΔLeu (9–11), and ΔIle (12–15) (Table 1).

Estudio de la interacción entre el ión Cu(II)y la fosfomicina (ácido L(cis) 1,2 epoxipropilfosfónico) en sus formas epóxido y glicol

1988

La experiencia es limitada en cuanto a las interacciones del ácido L-(cis) 1,2 epoxipropilfosfónico (fosfomicina, antibiótico de amplio espectro) con iones metálicos, aunque se sabe que los ácidos fosfónicos pueden interaccionar con metales como el Cu(II). El objetivo del estudio ha sido obtener un complejo de este ácido y su derivado glicólico (H2F(OH)2, ácido L-(cis) 1,2 dihidroxipropilfosfónico) con el Cu(II) para determinar las propiedades y efectos sobre el antibiótico. En solución acuosa de NaClO4 0.2M a 25 &#61617; 0.2ºC se obtienen dos especies CuF(OH)2 y CuFO(OH)-. El estudio espetrofotométrico permite deducir la existencia de dos puntos isosbésticos, los cuáles resultan útiles par…

Nucleotide sequence of the 18S rDNA from the microalgaNanochlorum eucaryotum

1988

Characterization of pea histone deacetylases

1988

The present paper is the first report on histone deacetylases from plants. Three enzyme fractions with histone deacetylase activity (HD0, HD1 and HD2) have been partially purified from pea (Pisum sativum) embryonic axes. They deacetylate biologically acetylated chicken histones and, to a lesser extent, chemically acetylated histones, this being a criterion of their true histone deacetylase nature. The three enzymes are able to accept nucleosomes as substrates. HD1 is not inhibited by n-butyrate up to 50 mM, whereas HD0 and HD2 are only slightly inhibited, thereby establishing a clear difference to animal histone deacetylases. The three activities are inhibited by acetate, Cu(2+) and Zn(2+) …

Comparison of the structures of cyclic fatty acid monomers isolated from heated linseed and sunflower oils

1988

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