In the interaction between two ecologically-associated species, the population structure of one species may affect the population structure of the other. Here, we examine the population structures of the aphid Metopeurum fuscoviride, a specialist on tansy Tanacetum vulgare, and its specialist primary hymenopterous parasitoid Lysiphlebus hirticornis, both of which are characterized by multivoltine

Popular Abstract in Swedish Homeostasen, dvs. bibehållandet av ett konstant antal blodceller, pågår genom hela livet och har sitt urprung från en sällsynt cell som huvudsakligen finns i benmärgen, där den utgör mindre än 1 cell på 10000-100000. Denna cell, den hematopoetiska stamcellen, ger upphov till alla blodprogenitorer (snabbväxande celler som har bestämt vilken typ av blodceller som de kan uHematopoietic stem cells and progenitor cells are maintained in the bone marrow microenvironment, where factors including soluble and membrane-bound cytokines influence the processes of self-renewal, proliferation and differentiation. Two nonreduntant cytokines with effects on hematopoiesis, Kit Ligand (KL) and Flt3 Ligand (FL), signal via related tyrosine kinase receptors, c-kit and Flt3. In this

As democracy encounters increasing difficulties, many citizens are turning to the domain of alternative politics, and in so doing, making considerable use of the Web and other new communication technologies. Clearly this is having significant impact, and we see that new modes of political participation and even political cultures are emerging. Yet, we would be foolish to expect some simple 'techno

In this paper, we propose a new system-level design language, called SystemJ. It extends Java with synchronous reactive features present in Esterel and asynchronous constructs suitable for modelling globally asynchronous locally synchronous systems. The strength of SystemJ comes from its ability to offer the data processing and encapsulation elegance of Java, Esterel-like reactivity and synchrony,

Popular Abstract in Swedish Komplex I eller NADH:kinon oxidoreduktas är det största och mest komplexa av de fem membranbunda enzymkomplexen som utgör den mitokondriella andningskedjan. Enzymet finns i alla typer av organismer från bakterier till däggdjur. Enzymet katalyserar oxidationen av NADH, som producerats i citronsyracykeln, och reduktion av fettlösligt kinon i membranet. Flavin och ett antaComplex I or NADH:quinone oxidoreductase the largest, most complex and least understood of the five membrane-bound enzyme complexes constituting the mitochondrial respiratory chain. The enzyme is present in all types of organisms, from bacteria to mammals. The enzyme catalyses the oxidation of NADH produced by the citric acid cycle and reduction of lipid soluble quinone in the membrane. Flavin and

This thesis introduces and summarizes four papers dealing with the study of double and multiple stars using space astrometry. The introduction gives a brief review of the role of binary observations in various fields of astronomy --- star formation, stellar masses and the mass-luminosity relation, initial mass function, detection of sub-stellar mass companions. The astrometric techniques are also

This paper investigates the implications of an endogenous social work norm for the optimal welfare state program. Assuming that individual productivity is observable, the analysis finds that restrictions on program participation, implying a larger benefit to a smaller group of recipients, may be welfare improving. However, the effect of the norm is indeterminate. The disutility of non-compliance s

Popular Abstract in Swedish En autonom agent kan definieras som ett system som med syfte att utföra uppgifter kan interagera med sin omgivning genom sina egna sensorer och effektorer. En ny arkitektur för autonoma agenter inspirerad av teorin för antecipatoriska system föreslås. Det är en hybrid arkitektur i det avseende att den kombinerar planerande förmåga, som behövs för att lösa långsiktiga prThis thesis has two main themes, autonomous agents and concepts. An autonomous agent is a system capable of interacting with its environment via its own sensors and effectors in order to accomplish some task. Arguments against both purely reactive and purely deliberative agent architectures are presented in favor for hybrid approaches. A novel hybrid approach based on the concept of anticipatory s

This paper describes a low distortion wide band CMOS direct digital RF amplitude modulator, which uses a 10-bit linear interpolation current steering digital to analog converter (DAC) and a Gilbert cell based mixer to generate an amplitude modulated RF signal directly. The linear interpolation increases the attenuation of the DAC's image components. The low pass filter (LPF) is therefore eliminate

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