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  • 1
    Electronic Resource
    Electronic Resource
    Allocating Weighted Jobs in Parallel (1999)
    Springer
    Theory of computing systems 32 (1999), S. 281-300 
    Details
    ISSN: 1433-0490
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract. The classic balls-into-bins game considers the experiment of placing m balls independently and uniformly at random (i.u.r.) in n bins. For m=n , it is well known that the maximum load, i.e., the number of balls in the fullest bin is Θ(log  n/log log  n) , with high probability. It is also known (see [S2]) that a maximum load of O( m / n ) can be obtained for all m≥ n if each ball is allocated in one (suitably chosen) of two (i.u.r.) bins. Stemann presents a distributed algorithm to find the ``suitable'' bin for each ball. The algorithm uses r communication rounds to achieve a maximum load of $\max\{\sqrt[r]{\log n}, O(m/n)\}$ , with high probability. Adler et al. [ACMR] show that Stemann's protocol is optimal up to a constant factor for constant r . In this paper we extend the above results in two directions: we generalize the lower bound to arbitrary r≤log log  n . This implies that Stemann's protocol is optimal for all r . Our key result is a generalization of Stemann's upper bound to weighted balls: Let W A (resp. W M ) denote the average (resp. maximum) weight of the balls. Furthermore, let Δ=W A /W M . Then the optimal maximum load is Ω(m/n⋅ W A +W M ) . We present a protocol that achieves a maximum load of γ⋅( m / n ⋅ W A +W M ) using O( log log  n / log  (γ⋅(m/n⋅Δ+1)) ) communication rounds. For uniform weights this matches the results of Stemann. In particular, we achieve a load of O( m / n ⋅ W A +W M ) using log log  n communication rounds, which is optimal up to a constant factor. An extension of our lower bound shows that our algorithm also reaches a load which is within a constant factor of the optimal load in the case of weighted balls. All the balls-into-bins games model load balancing problems: the balls are jobs, the bins are resources, the task is to allocate the jobs to the resources in such a way that the maximum load is minimized. Our extension to weighted balls allows us to extend previous bounds to models where resource requirements may vary. For example, if the jobs are computing tasks, their running times may vary. Applications of such load balancing problems occur, e.g., for client-server networks and for multimedia-servers using disk arrays.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002240000119
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  • 2
    Electronic Resource
    Electronic Resource
    Ionic imbalance as a source of toxicity in an estuarine effluent (1996)
    Springer
    Archives of environmental contamination and toxicology 31 (1996), S. 426-432 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract A toxicity identification evaluation (TIE) was conducted on the effluent from a petrochemical plant which discharges into an estuary. The effluent had been consistently toxic to mysid shrimp (Mysidopsis bahia) but not toxic to sheepshead minnows (Cyprinodon variegatus). Phase I effluent toxicity characterization tests revealed that treatment of the effluent with a cation exchange resin (Amberlite® IR-120 Plus) was partially effective at reducing, but not removing, toxicity. Phase II characterization tests revealed that four cations varied with toxicity: Ca and Sn were positively correlated with increasing toxicity; Mg and K were negatively correlated with increasing toxicity. Toxicity tests with SnCl2 revealed that the toxicity threshold for Sn was far above the concentrations present in the raw effluent. Reduction of Ca was shown to result in a significant improvement in survival, but some toxicity still remained. Further augmentation of the treated effluent with CaCl2, MgCl2, and KBr to restore the concentrations of Ca, Mg, K, and Br to natural seawater concentrations resulted in survival of all exposed organisms. Repeated success of this treatment regime on additional samples of the effluent as well as “mock effluent” studies confirmed that ion imbalance was the sole source of toxicity in this effluent. Process source water composition and essential ion balance are discussed as important components of marine effluent TIEs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212683
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  • 3
    Electronic Resource
    Electronic Resource
    Ionic Imbalance as a Source of Toxicity in an Estuarine Effluent (1996)
    Springer
    Archives of environmental contamination and toxicology 31 (1996), S. 426-432 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. A toxicity identification evaluation (TIE) was conducted on the effluent from a petrochemical plant which discharges into an estuary. The effluent had been consistently toxic to mysid shrimp (Mysidopsis bahia) but not toxic to sheepshead minnows (Cyprinodon variegatus). Phase I effluent toxicity characterization tests revealed that treatment of the effluent with a cation exchange resin (Amberlite® IR-120 Plus) was partially effective at reducing, but not removing, toxicity. Phase II characterization tests revealed that four cations varied with toxicity: Ca and Sn were positively correlated with increasing toxicity; Mg and K were negatively correlated with increasing toxicity. Toxicity tests with SnCl2 revealed that the toxicity threshold for Sn was far above the concentrations present in the raw effluent. Reduction of Ca was shown to result in a significant improvement in survival, but some toxicity still remained. Further augmentation of the treated effluent with CaCl2, MgCl2, and KBr to restore the concentrations of Ca, Mg, K, and Br to natural seawater concentrations resulted in survival of all exposed organisms. Repeated success of this treatment regime on additional samples of the effluent as well as “mock effluent” studies confirmed that ion imbalance was the sole source of toxicity in this effluent. Process source water composition and essential ion balance are discussed as important components of marine effluent TIEs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002449900128
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  • 4
    Electronic Resource
    Electronic Resource
    Deletion mapping by FISH with BACs in patients with partial monosomy 22q13 (1998)
    Springer
    Human genetics 〈Berlin〉 102 (1998), S. 557-561 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Patients with deletions in 22q13 are known to have phenotypic features that include normal or accelerated growth, large hands and feet, hypotonia, delayed psychomotor development and mild facial dysmorphism. To date, very few cases have been investigated by detailed molecular genetic analysis. We have analyzed three new patients with terminal deletions in 22q. We compared the cytogenetic observations with molecular data assessed by fluorescence in situ hybridization and an array of characterized bacterial artificial chromosome recombinants. The shortest region of deletion overlap is localized in 22q13.2–qter distal to the marker D22S94, but the telomeric repeat in the deleted chromosome appears to remain intact. When parental alleles were investigated in two of the three patients, the aberrant homolog was found to be of paternal origin in both cases. Although the deleted region still spans 〉20 cM, molecular analysis of additional patients and screening for new genes might help in elucidating candidate genes connected with the dysmorphisms defined by deletions of 22q13.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004390050739
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  • 5
    Electronic Resource
    Electronic Resource
    A ribozyme gene and an antisense gene are equally effective in conferring resistance to tobacco mosaic virus on transgenic tobacco (1996)
    Springer
    Molecular genetics and genomics 250 (1996), S. 329-338 
    Details
    ISSN: 1617-4623
    Keywords: Key words RNA cleavage ; Hammerhead ribozymes ; Antisense RNA ; Antiviral agents ; In vivo expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Ribozymes of the hammerhead class can be designed to cleave a target RNA in a sequence-specific manner and can potentially be used to specifically modulate gene activity. We have targeted the tobacco mosaic virus (TMV) genome with a ribozyme containing three catalytic hammerhead domains embedded within a 1 kb antisense RNA. The ribozyme was able to cleave TMV RNA at all three target sites in vitro at 25° C. Transgenic tobacco plants were generated which expressed the ribozyme or the corresponding antisense constructs directed at the TMV genome. Six of 38 independent transgenic plant lines expressing the ribozyme and 6 of 39 plant lines expressing the antisense gene showed some level of protection against TMV infection. Homozygous progeny of some lines were highly resistant to TMV; at least 50% of the plants remained asymptomatic even when challenged with high levels of TMV. These plants also displayed resistance to infection with TMV RNA or the related tomato mosaic virus (ToMV). In contrast, hemizygous plants of the same lines displayed only very weak resistance when inoculated with low amounts of TMV and no resistance against high inoculation levels. Resistance in homozygous plants was not overcome by a TMV strain which was altered at the three target sites to abolish ribozyme-mediated cleavage, suggesting that the ribozyme conferred resistance primarily by an antisense mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174391
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  • 6
    Electronic Resource
    Electronic Resource
    A ribozyme gene and an antisense gene are equally effective in conferring resistance to tobacco mosaic virus on transgenic tobacco (1996)
    Springer
    Molecular genetics and genomics 250 (1996), S. 329-338 
    Details
    ISSN: 1617-4623
    Keywords: RNA cleavage ; Hammerhead ribozymes ; Antisense RNA ; Antiviral agents ; In vivo expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ribozymes of the hammerhead class can be designed to cleave a target RNA in a sequence-specific manner and can potentially be used to specifically modulate gene activity. We have targeted the tobacco mosaic virus (TMV) genome with a ribozyme containing three catalytic hammerhead domains embedded within a 1 kb antisense RNA. The ribozyme was able to cleave TMV RNA at all three target sites in vitro at 25°C. Transgenic tobacco plants were generated which expressed the ribozyme or the corresponding antisense constructs directed at the TMV genome. Six of 38 independent transgenic plant lines expressing the ribozyme and 6 of 39 plant lines expressing the antisense gene showed some level of protection against TMV infection. Homozygous progeny of some lines were highly resistant to TMV; at least 50% of the plants remained asymptomatic even when challenged with high levels of TMV. These plants also displayed resistance to infection with TMV RNA or the related tomato mosaic virus (ToMV). In contrast, hemizygous plants of the same lines displayed only very weak resistance when inoculated with low amounts of TMV and no resistance against high inoculation levels. Resistance in homozygous plants was not overcome by a TMV strain which was altered at the three target sites to abolish ribozyme-mediated cleavage, suggesting that the ribozyme conferred resistance primarily by an antisense mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174391
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  • 7
    Electronic Resource
    Electronic Resource
    Beitrag zum Verfestigungsverhalten der Stähle durch Kaltverformung (1980)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 11 (1980), S. 73-76 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Hardening Behaviour of Steels by Cold WorkingContrary to common opinion work hardening increases with higher initial hardness (strength) of steel. This is proved by analysing stressstrain curves of tensile tests at overeleastic load carried out with normalized, hardened and tempered steel. Test results taken from literature are supported by own experiments. Practical application of this fact is discussed very shortly.
    Notes: Bei Stählen steigt im Gegensatz zur herrschenden Meinung die Kaltverfestigung (Aufhärtung) mit steigender Ausgangshärte oder -festigkeit an. Dies wird nachgewiesen an Ergebnissen aus Zugversuchen mit normalisierten und vergüteten Stählen. Ergebnisse der Literatur werden durch eigene Versuche ergänzt. Die praktische Nutzanwendung dieses Tatbestandes wird knapp andiskutiert.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19800110209
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  • 8
    Electronic Resource
    Electronic Resource
    Zur Meßstellenpräparation für Eigenspannungsmessungen (1982)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 13 (1982), S. 313-316 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Der Eigenspannungsmeßtechnik wurden in den letzten Jahrzehnten viele Arbeiten gewidmet mit einem Trend der Vorliebe zur röntgenographischen Meßmethode und deren Anwendung. 1979 wurde in einem Symposium der Arbeitsgemeinschaft für Wärmebehandlung und Werkstofftechnik e. V., des Deutschen Verbandes für Materialprüfung e. V. und der Deutschen Gesellschaft für Metallkunde e. V. der Stand der Wissenschaft zum Thema „Eigenspannungen“, Entstehung, Berechnung, Messung und Bewertung, in Deutschland abgehandelt [1]. Vorgetragen wurden neben der reinen Theorie einige praxisbezogene Studien über Bauteile, bei denen der Verlauf der Eigenspannungen ermittelt und studiert wurde, was in jedem Fall die Zerstörung des Bauteils zur Folge hat.Anwendungen der Eigenspannungsmessung zur Fertigungskontrolle sind in der Literatur selten.Dennoch, neben diesen zum Teil uralten Betrachtungen gibt es in der Praxis Fälle, bei denen der prinzipielle Spannungsverlauf im Bauteil bekannt ist und zur Fertigungskontrolle eine praktisch zerstörungsfreie Eigenspannungsmessung der Oberfläche notwendig ist. Diesen Messungen steht ein grundsätzliches Problem entgegen: Die zu vermessende Oberfläche muß relevant sein für den wahren Spannungszustand des Bauteils. Aber die Oberfläche stellt eine singuläre Zone dar, deren Spannungszustand durch alle oberflächenaktiven Vorgänge verfälscht wird; je zerstörungsfreier das Meßverfahren, umso sensibler ist die Messung gegen die Meßstellen-(Oberflächen-)Singularität. Um nur einige Beispiele von Oberflächensingularitäten bei Stahl zu erwähnen, sei erinnert an Entkohlung, Verfestigung durch Grobzerspanung, Verhärtungen oder Anlasseffekte durch Schleifen usw., wobei der Gradient der jeweiligen Beeinflussung von vielen Parametern abhängt und im Regelfall unbekannt bleibt.In dieser Arbeit soll berichtet werden, wie und mit welchem Aufwand für einen speziellen Anwendungsfall das Problem der Meßstellenrelevanz gelöst wurde.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19820130906
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  • 9
    Electronic Resource
    Electronic Resource
    PM Aluminum Camshaft Belt Pulleys for Automotive Engines (1996)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 27 (1996), S. 179-189 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Sinteraluminium-Zahnriemenräder für KraftfahrzeugmotorenLeichte und gleichzeitig verschleißfeste Zahnriemenräder auf Al-Basis für Motoren wurden aus üblichen Al-Pulvermischungen mit Zusatz von harten Teilchen hergestellt. Beim Vergleich der Einlagerungen ergab sich der Zusatz von 10 Masse% ZrSiO4 als optimal. Aus der entsprechenden Mischung wurden Zahnriemenräder gepreßt, unter optimierten Bedingungen gesintert und kalibriert. Für die Verschleißpruüfung wurden sowohl Stift-Scheibe-Geräte als auch speziell entwickelte Zahnriemenradprüfstände verwendet. Die Al-Räder waren sowohl von den Dimensionen als auch der Verschleißbeständigkeit her durchaus mit üblichen Sintereisenrädern vergleichbar, mit Ausnahme eines gewissen Verschleißes des Riemens durch herauspolierte Teilchen nach sehr langen Prüfzeiten.
    Notes: Light and wear resistant Al camshaft belt pulleys for engines were produced from standard Al powder mixtures with addition of hard particles. Pre-screening tests of numerous inclusions showed 10 mass% ZrSiO4 to be the best choice. Full size belt pulleys were produced by pressing, sintering at optimized parameters, and sizing. Wear testing was carried out on pin-disc testers and special belt pulley testbeds. Both dimensional and wear properties were found to be well comparable to those of conventional iron pulleys, with the exception of some attack on the belt by protruding particles after prolonged testing.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19960270413
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  • 10
    Electronic Resource
    Electronic Resource
    Surface analysis of PP/EVA blends modified with amino acids for biomedical applications (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 699-710 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The copolymers poly(propylene-co-ethylene) (PP/E) and poly(ethylene-co-vinyl acetate) (EVA) and blends of these were modified to develop an artificial matrix which promotes the growth of endothelial cells. Covalent immobilization of amino acids or sequences of adhesion glycoproteins should trigger the formation of an endothelial cell monolayer onto the polymeric surface. Reactive functional groups were generated by saponifying the ester groups of the EVA component. Esterification with oxalylic or malonic dichlorides in the gas phase yielded the required monoesters and gave the best results for further immobilization of amino acids, while reaction with α,ω-dicarboxylic acid dichlorides in solution led to diester formation. Subsequently, various protected amino acids were immobilized via the carbodiimide method. Surface analytical methods like infrared spectroscopy using at tenuated total reflection (IR-ATR), X-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS) were used to prove the modification steps. The analytical results confirmed covalent side-chain generation in the upper surface region. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070580403
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