Unspeakable quantum information

No verbal explanation can indicate a direction in space or the orientation of a coordinate system. Only material objects can do it. In this article we consider the use of a set of spin-\half particles in an entangled state for indicating a direction, or a hydrogen atom in a Rydberg state for transmitting a Cartesian frame. Optimal strategies are derived for the emission and detection of the quantum signals.Comment: to appear in "Quantum Theory: Reconsideration of Foundations", ed. by A. Khrennikov; series ``Math. Modelling in Physics, Engineering and Cognitive Sciences'' V\"axj\"o Univ. Press (2002) - requires sprocl.st

Carotenoid biosynthesis and overproduction in Corynebacterium glutamicum

Heider S, Peters-Wendisch P, Wendisch VF. Carotenoid biosynthesis and overproduction in Corynebacterium glutamicum. BMC Microbiology. 2012;12(1): 198.Background Corynebacterium glutamicum contains the glycosylated C50 carotenoid decaprenoxanthin as yellow pigment. Starting from isopentenyl pyrophosphate, which is generated in the non-mevalonate pathway, decaprenoxanthin is synthesized via the intermediates farnesyl pyrophosphate, geranylgeranyl pyrophosphate, lycopene and flavuxanthin. Results Here, we showed that the genes of the carotenoid gene cluster crtE-cg0722-crtBIYeYfEb are co-transcribed and characterized defined gene deletion mutants. Gene deletion analysis revealed that crtI, crtEb, and crtYeYf, respectively, code for the only phytoene desaturase, lycopene elongase, and carotenoid C45/C50 epsilon-cyclase, respectively. However, the genome of C. glutamicum also encodes a second carotenoid gene cluster comprising crtB2I2-1/2 shown to be co-transcribed, as well. Ectopic expression of crtB2 could compensate for the lack of phytoene synthase CrtB in C. glutamicum DeltacrtB, thus, C. glutamicum possesses two functional phytoene synthases, namely CrtB and CrtB2. Genetic evidence for a crtI2-1/2 encoded phytoene desaturase could not be obtained since plasmid-borne expression of crtI2-1/2 did not compensate for the lack of phytoene desaturase CrtI in C. glutamicum DeltacrtI. The potential of C. glutamicum to overproduce carotenoids was estimated with lycopene as example. Deletion of the gene crtEb prevented conversion of lycopene to decaprenoxanthin and entailed accumulation of lycopene to 0.03 +/- 0.01 mg/g cell dry weight (CDW). When the genes crtE, crtB and crtI for conversion of geranylgeranyl pyrophosphate to lycopene were overexpressed in C. glutamicum DeltacrtEb intensely red-pigmented cells and an 80 fold increased lycopene content of 2.4 +/- 0.3 mg/g CDW were obtained. Conclusion C. glutamicum possesses a certain degree of redundancy in the biosynthesis of the C50 carotenoid decaprenoxanthin as it possesses two functional phytoene synthase genes. Already metabolic engineering of only the terminal reactions leading to lycopene resulted in considerable lycopene production indicating that C. glutamicum may serve as a potential host for carotenoid production

Entrepreneurship, Dynamic Capabilities and New Firm Growth

This paper applies the dynamic capability framework to the study of new firm growth. Using a longitudinal database of 354 firms over their first ten years, we provide an explanation of new firm growth in terms of new product development, R&D, inter-firm alliancing, and exporting, activities that have been identified as denoting dynamic capabilities. In addition, an overview of empirical studies on employment growth in new firms is provided. The empirical evidence for this study shows that general firm resources have a much stronger effect on growth than the dynamic capabilities measured here (mainly inter-firm alliancing). High levels of human capital of the entrepreneur or resourcemunificence of the firm does not improve the value of dynamic capabilities for growth. Environmental dynamism ? a supposed boundary condition of the dynamic capability approach ? is not revealed to be a moderating factor on the effect of dynamic capabilities on new firm growth.

Employment Growth of New Firms

This paper provides an overview of empirical studies on employment growth in new firms and offers a systematic analysis of new empirical data to address the methodological issues identified. Using a longitudinal database of 354 firms over their first ten years, we examine factors associated with new firm growth in terms of R&D, inter-firm alliancing, new product development, and exporting; these are activities that have been identified as denoting dynamic capabilities. The empirical evidence gives some evidence for the positive association between dynamic capabilities and new firm growth. Inter-firm alliancing is the only indicator of dynamic capabilities that has a positive effect on new firm growth. No moderating effect on dynamic capabilities and growth could be seen to be exerted by the level of human capital and/or firm resources. Environmental dynamism – assumed to be highly relevant in the dynamic capability approach – is not revealed to be a moderating factor affecting the relationship between dynamic capabilities and new firm growth.

Weak limits for quantum random walks

We formulate and prove a general weak limit theorem for quantum random walks in one and more dimensions. With $X_n$ denoting position at time $n$, we show that $X_n/n$ converges weakly as $n \to \infty$ to a certain distribution which is absolutely continuous and of bounded support. The proof is rigorous and makes use of Fourier transform methods. This approach simplifies and extends certain preceding derivations valid in one dimension that make use of combinatorial and path integral methods