Expressing the operations of quantum computing in multiparticle geometric algebra

We show how the basic operations of quantum computing can be expressed and manipulated in a clear and concise fashion using a multiparticle version of geometric (aka Clifford) algebra. This algebra encompasses the product operator formalism of NMR spectroscopy, and hence its notation leads directly to implementations of these operations via NMR pulse sequences.Comment: RevTeX, 10 pages, no figures; Physics Letters A, in pres

Extracting Classical Correlations from a Bipartite Quantum System

In this paper we discuss the problem of splitting the total correlations for a bipartite quantum state described by the Von Neumann mutual information into classical and quantum parts. We propose a measure of the classical correlations as the difference between the Von Neumann mutual information and the relative entropy of entanglement. We compare this measure with different measures proposed in the literature.Comment: 5 pages, 1 figur

CYTOLOGICAL EVIDENCE FOR A RELATIONSHIP BETWEEN NORMAL HEMATOPOIETIC COLONY-FORMING CELLS AND CELLS OF THE LYMPHOID SYSTEM

The relationship between hematopoietic colony-forming stem cells and cells in the thymus and lymph nodes of unirradiated mice has been investigated using a chromosome-marker technique. It was found that a high proportion of cells in the thymus may belong to the same clone as normal hematopoietic colony-forming cells. It was also found that cells belonging to the same clone as colony-forming cells may reach the lymph nodes, and that nodes containing such cells can participate in an immunological response against sheep red cells. Either the precursors of cells in thymus and lymph node are identical with hematopoietic colony-forming cells, or they are both descendants of a common precursor which has not yet been identified. The results are compatible with the view that cells of the hematopoietic system and the immune system may be derived from the same stem cell

Integral CFLs performance in table lamps

This paper focuses on performance variations associated with lamp geometry and distribution in portable table luminaires. If correctly retrofit with compact fluorescent lamps (CFLs), these high use fixtures produce significant energy savings, but if misused, these products could instead generate consumer dissatisfaction with CFLs. It is the authors assertion that the lumen distribution of the light source within the luminaires plays a critical role in total light output, fixture efficiency and efficacy, and, perhaps most importantly, perceived brightness. The authors studied nearly 30 different integral (screw-based) CFLs available on the market today in search of a lamp, or group of lamps, which work best in portable table luminaires. The findings conclusively indicate that horizontally oriented CFLs outperform all other types of CFLs in nearly every aspect

MULTIPLICATION OF ANIMAL CELLS IN SUSPENSION MEASURED BY COLONY COUNTS

Archived with permission from the National Academy of Sciences USA. Originally published in Proceedings of the National Academy of Sciences USA volume 43 issue 6. Please refer to www.pnas.org for this series of publications. Author holds all copyright for this article.During the past few years the development of new techniques for the cultivation of animal cells in vitro has facilitated the quantitative study of many aspects of cell biology. At present the most commonly used method of propagating cell strains is based on the ability of cells to multiply while attached to a glass surface. The cells may be subcultured by removing them from the surface into suspension and then distributing them into other vessels, where they will again adhere to the glass and populate the surface. This procedure has been developed by Earle and his associates into the so-called quantitative replicate culture technique and applied to a variety of studies with animal cells. Despite the technical advance represented by this method, there are, nevertheless, serious experimental limitations inherent in the use of glass surfaces for cultivating large cell populations. Perhaps the most obvious of these is the problem of removing representative samples at will during the growth of a cell population. In addition, subculture requires the removal of cells from the surface, with consequent risk of cell injury.Aided in part by grants from the National Foundation for Infantile Paralysis, the Public Health Service of the National Institutes of Health of the United States, the National Cancer Institute of Canada, and the W. B. Boyd Memorial Fun

Fyn and PTP-PEST–mediated Regulation of Wiskott-Aldrich Syndrome Protein (WASp) Tyrosine Phosphorylation Is Required for Coupling T Cell Antigen Receptor Engagement to WASp Effector Function and T Cell Activation

Involvement of the Wiskott-Aldrich syndrome protein (WASp) in promoting cell activation requires its release from autoinhibitory structural constraints and has been attributed to WASp association with activated cdc42. Here, however, we show that T cell development and T cell receptor (TCR)-induced proliferation and actin polymerization proceed normally in WASp−/− mice expressing a WASp transgene lacking the cdc42 binding domain. By contrast, mutation of tyrosine residue Y291, identified here as the major site of TCR-induced WASp tyrosine phosphorylation, abrogated induction of WASp tyrosine phosphorylation and its effector activities, including nuclear factor of activated T cell transcriptional activity, actin polymerization, and immunological synapse formation. TCR-induced WASp tyrosine phosphorylation was also disrupted in T cells lacking Fyn, a kinase shown here to bind, colocalize with, and phosphorylate WASp. By contrast, WASp was tyrosine dephosphorylated by protein tyrosine phosphatase (PTP)-PEST, a tyrosine phosphatase shown here to interact with WASp via proline, serine, threonine phosphatase interacting protein (PSTPIP)1 binding. Although Fyn enhanced WASp-mediated Arp2/3 activation and was required for synapse formation, PTP-PEST combined with PSTPIP1 inhibited WASp-driven actin polymerization and synapse formation. These observations identify key roles for Fyn and PTP-PEST in regulating WASp and imply that inducible WASp tyrosine phosphorylation can occur independently of cdc42 binding, but unlike the cdc42 interaction, is absolutely required for WASp contributions to T cell activation