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  • 1
    Electronic Resource
    Electronic Resource
    Approximation Algorithms for the Fixed-Topology Phylogenetic Number Problem (1999)
    Springer
    Algorithmica 25 (1999), S. 311-329 
    Details
    ISSN: 1432-0541
    Keywords: Key words. Phylogeny, Approximation algorithm, Computational biology.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. In the l -phylogeny problem, one wishes to construct an evolutionary tree for a set of species represented by characters, in which each state of each character induces no more than l connected components. We consider the fixed-topology version of this problem for fixed-topologies of arbitrary degree. This version of the problem is known to be NP -complete for l ≥ 3 even for degree-3 trees in which no state labels more than l+1 leaves (and therefore there is a trivial l + 1 phylogeny). We give a 2 -approximation algorithm for all l ≥ 3 for arbitrary input topologies and we give an optimal approximation algorithm that constructs a 4 -phylogeny when a 3 -phylogeny exists. Dynamic programming techniques, which are typically used in fixed-topology problems, cannot be applied to l -phylogeny problems. Our 2 -approximation algorithm is the first application of linear programming to approximation algorithms for phylogeny problems. We extend our results to a related problem in which characters are polymorphic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00008280
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  • 2
    Electronic Resource
    Electronic Resource
    Dissociation of biochemical and hypotensive effects of debrisoquine in hypertensive patients (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 81-86 
    Details
    ISSN: 1432-1041
    Keywords: debrisoquine ; hypertension ; renin ; catecholamines ; platelet monoamine oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The 24 h urinary excretion of adrenaline, noradrenaline, metadrenaline, normetadrenaline and vanillylmandelic acid, plasma renin activity and plasma and urinary debrisoquine were measured before and during chronic treatment with oral debrisoquine in 14 in-patients with essential hypertension. There was a significant fall (mean ±SD) in the 24 h urinary excretion of vanillylmandelic acid (15.3±2.8 to 6.7±1.9 µmol) noradrenaline (199.0±105.8 to 125.2±43.3 nmol) and plasma renin activity (0.71±0.47 to 0.40±0.20 pmol Angio I ml−1 h−1) while the urinary normetadrenaline/noradrenaline ratio increased (10.4±6.1 to 17.1±5.1). No significant change was seen in the output of adrenaline or of O-methylated metabolites. Debrisoquine produces extensive noncompetitive inhibition of platelet monoamine oxidase in vivo at low therapeutic plasma concentrations. These changes support the view that treatment with debrisoquine produces intraneuronal inhibition of monoamine oxidase and post-ganglionic blockage. There was a significant correlation between the change in standing diastolic blood pressure and the daily dose (rs=−0.52), pre-dose plasma concentration (rs=−0.85) and mean daily urinary recovery (rs=−0.80), of debrisoquine. The full extent of the biochemical changes were seen at low dose and low plasma concentration and were not directly correlated with the fall in standing or supine blood pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00563111
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  • 3
    Electronic Resource
    Electronic Resource
    The use of Thiabendazole for the post-harvest treatment of bananas (1970)
    Oxford, UK : Blackwell Publishing Ltd
    International journal of food science & technology 5 (1970), S. 0 
    Details
    ISSN: 1365-2621
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary. Studies were carried out to assess the efficacy of thiabendazole (TBZ or [2-(4-thiazolyl)benzimidazole]) in controlling fungal rot damage of bananas in the Windward Islands. A dipping treatment proved to be more effective, especially in the reduction of rot in the banana cushions, than application of the fungicide by spraying, but both methods of application resulted in a very satisfactory control of fungal rots. Chemical analysis of the treated bananas showed that regardless of mode of application and location on the hand the residue levels were well below the limits permitted by American standards.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1970.tb01545.x
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  • 4
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    Home video game playing in schoolchildren: a study of incidence and patterns of play (1995)
    London : Periodicals Archive Online (PAO)
    Journal of adolescence. 18:6 (1995) 687 
    Details
    ISSN: 0140-1971
    Topics: Psychology
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:d137-1995-018-06-000006
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  • 5
    Electronic Resource
    Electronic Resource
    Antiquity of clonal salamander lineages revealed by mitochondrial DNA (1992)
    [s.l.] : Nature Publishing Group
    Nature 356 (1992), S. 706-708 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Triploid, gynogenetically reproducing lineages of mole salamanders are abundant in the northeastern United States and southeastern Canada16. They arose by hybridization between A. jeffersonianum and A. laterale16'19 and, except for irregularities in occasional individuals, contain either two ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/356706a0
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  • 6
    Electronic Resource
    Electronic Resource
    Leg exerciser for training of paralysed muscle by closed-loop control (1984)
    Springer
    Medical & biological engineering & computing 22 (1984), S. 298-303 
    Details
    ISSN: 1741-0444
    Keywords: Dynamic exercise ; Endurance ; Exercise Muscle ; Paralysis ; Rehabilitation ; Strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract An exercise device which can be used to stimulate either paralysed or nonparalysed muscles is described. The device uses sequential activation of muscles to elicit either isometric or isotonic contractions. Feedback sensors provide the relative position of the joints of the leg to a computer-controlled two-channel sequential stimulatior which regulates the activity of the muscles. The computer can be programmed to preprogram workouts so that the muscle can move throught patterns of activity requiring either isometric exeroise, isokinetic exercise or isotonic exercise. In all cases the computer controls the entire exercise program and automatically terminates when the muscle is fatigued. THis device could be used for any type of physical therapy involving active stimulation of muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442096
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  • 7
    Electronic Resource
    Electronic Resource
    Noninvasive cardiac material mechanics: Application to left ventricular function in quadriplegia (1988)
    Springer
    Medical & biological engineering & computing 26 (1988), S. 333-341 
    Details
    ISSN: 1741-0444
    Keywords: Area ratio ; Echocardiography ; Myocardial wall deformation ; Quadriplegia ; System time constant ; Viscoelastic compliance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Left ventricular function was studied in six quadriplegic subjects by M-mode echocardiography with respect to cardiac material mechanics. Myocardial wall deformation and ventricular viscoelastic compliance were studied during systole and diastole. The left ventricle was assumed to be a sphere and to keep this shape over the cardiac cycle. The viscoelastic properties were determined with respect to the mid-wall. The haemodynamic results indicated that the ejection fraction of quadriplegics was significantly greater than in normals but that their cardiac output was significantly lower. The ratio of viscous compliance coefficient to elastic compliance coefficient was called the system time constant. The myocardial material results indicated that the inequality diastolic time constant ≤ systolic time constant was satisfied in the six quadriplegics. The ratio of end-systolic to end-diastolic wall area was significantly greater in quadriplegics than in normals. These results were consistent with the left ventricle of quadriplegics being deconditioned so that the ventricular wall is more compliant during systole and myocardial wall deformation is greater.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442288
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  • 8
    Electronic Resource
    Electronic Resource
    Determination of the contractile characteristics of the motor units in skeletal muscle through twitch characteristics (1979)
    Springer
    Medical & biological engineering & computing 17 (1979), S. 525-533 
    Details
    ISSN: 1741-0444
    Keywords: Contractile characteristics ; Motor units ; Muscle ; Twitch characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A stepwise increase in stimulation voltage was applied to a pair of synchronously firing plate electrodes placed across the spinal roots innervating the soleus, medial and lateral gastrocnemius muscles of the cat. The resultant muscle twitches were stored and analysed by an Intel 8080a microprocessor to determine the speed of contraction and the peak tension of the compound muscle twitches. From these results, the speed of contraction and the strength distribution of the motor units within that muscle were estimated. These data were then compared with the actual fibre composition and speed distribution measured for the same three muscles. The results of these determinations showed that the distribution of strength and speed of contraction of the motor units of these muscles could be approximated through stimulation of their motor nerves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02447068
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  • 9
    Electronic Resource
    Electronic Resource
    Constant-velocity contractions in skeletal muscle by sequential stimulation of muscle efferents (1979)
    Springer
    Medical & biological engineering & computing 17 (1979), S. 583-592 
    Details
    ISSN: 1741-0444
    Keywords: Dynamic exercise ; E.M.G., Length/tension ; relationship ; Recruitment ; Rehabilitative medicine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Experiments are described that quantify the relationship between the contraction velocity, the recruitment of motor units and the electrical activity in the medial gastrocnemius muscle of the cat. The results of these experiments showed that, with differing degrees of activation, the force/velocity relationship closely followed that described by Hill. The electrical activity in the muscle was directly related to recruitment and was also linearly related to the load at any constant velocity of contraction. With progressively higher velocities of contraction, however, for any given load, the electrical activity was also increased. From the above database a computer program and the associated hardware were developed to stimulate muscle and cause it to maintain constant velocity contractions irrespective of the load imposed on the muscle. The applications of this type of stimulation to the restoration of mobility to the paralysed are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02440903
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  • 10
    Electronic Resource
    Electronic Resource
    The influence of recruitment order and fibre composition on the force-velocity relationship and fatiguability of skeletal muscles in the cat (1980)
    Springer
    Medical & biological engineering & computing 18 (1980), S. 381-390 
    Details
    ISSN: 1741-0444
    Keywords: Fast and slow muscle ; Force-velocity relationship ; Mathematical model ; Muscle fatigue ; Paralysis ; Recruitment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Two of the lower leg muscles of the cat were examined to assess the influence of the order in which motor units are recruited (slowest to fastest or fastest to slowest) and the fibre composition on the force-velocity relationship and fatiguability of skeletal muscle. The muscles examined were the soleus, a slow twitch muscle, and the medial head of the gastrocnemius muscle, a predominantly fast twitch muscle of mixed composition. The results of these experiments showed that the force-velocity relationship was a function of both the order of motor unit recruitment and the fibre composition of the muscles. However, at either recruitment order, the ability of the computer to control the velocity of contraction and the resultant fatiguability of the muscle for these contractions was similar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02443305
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