Molecular genetic analysis of chemical-induced sporulation of Myxococcus xanthus

Mutants resistant to glycerol-induction of sporulation were isolated from wild-type M. xanthus. The glycerol-resistant qlrA and alrB loci, previously mapped by Mx.8 transductions, were analysed by restriction mapping of clones and by complementation analysis. The location of the qlrA gene(s) was mapped to within a 2.2kb region, whilst the qlrB region proved very complex. The qlrA and qlrB gene products were reguired early in chemical-induced sporulation since two chemical-inducible lacZ fusions were not expressed in either qlrA or qlrB mutants during chemical-induction. Only a minority of the glycerol-resistant mutants were unable to undergo fruiting body sporulation. Complementation studies of the qlrA and qlrB regions confirmed that mutations in chemical-induced and fruiting body sporulation were not linked. This suggests that the induction pathways of chemical-induced sporulation and fruiting body sporulation share few common genes. Glycerol-resistant mutants were isolated from a non- motile strain, which is unable to form fruiting bodies. The majority of these mutants were able to form spores in the absence of fruiting bodies. Two mutants were unable to form spores. Isolating such mutants may provide a means of identifying truly sporulation-deficient mutants. Expression from the chemical-inducible isqB>lacZ fusion, identified previously in a promoter probe vector, was blocked in 24 different glycerol-resistant mutants. Hence, the gene product was reguired late in the chemical-induced sporulation pathway. The complete transcription unit was cloned and disruption of the region by the insertion of a tetracycline cassette demonstrated that the gene is not essential for chemical- induced or starvation-induced sporulation. Expression from a second chemical-inducible lacZ fusion, ÎÎDK4530, identified previously by random Tn£ lac insertion, was suppressed by amino acids in the growth media during chemical-induced sporulation and was blocked in both qlrA and qlrB mutants. Hence, expression of the gene product is dependent on both the qlrA+ and qlrB+ genes

Geographical catch distribution of yellowfin and skipjack tuna in the Eastern Pacific Ocean, 1967-1970, and fleet and total catch statistics, 1962-1970

ENGLISH: Logbook records of tuna vessels fishing in the eastern Pacific Ocean were used to prepare charts showing the distribution of yellowfin tuna and skipjack catches by i-degree area, by quarter of the year, and by gear, for the years 1967-1970. Recent changes in the geographical distribution of yellowfin catch are illustrated. Also given are annual catch statistics and the composition of the international tuna fishing fleets which operated in the Commission's Yellowfin Regulatory Area each year, 1962-1970. SPANISH: Los registros de los cuadernos de bitácora de los barcos pesqueros de atún en el Océano Pacífico oriental se usaron para preparar gráficos que presentan para los años de 1967-1970, la distribución de captura del atún aleta amarilla y barrilete por área de 1 grado, trimestre del año y, por las artes. Se ilustran los recientes cambios en la distribución geográfica de la captura del atún aleta amarilla. Se presentan también las estadísticas de captura anual y la composición de la flota internacional de pesca, que explota cada año el Area Reglamentaria de la Comisión, 1962-1970. (PDF contains 95 pages.

Cosmic Equilibration: A Holographic No-Hair Theorem from the Generalized Second Law

In a wide class of cosmological models, a positive cosmological constant drives cosmological evolution toward an asymptotically de Sitter phase. Here we connect this behavior to the increase of entropy over time, based on the idea that de Sitter spacetime is a maximum-entropy state. We prove a cosmic no-hair theorem for Robertson-Walker and Bianchi I spacetimes that admit a Q-screen ("quantum" holographic screen) with certain entropic properties: If generalized entropy, in the sense of the cosmological version of the Generalized Second Law conjectured by Bousso and Engelhardt, increases up to a finite maximum value along the screen, then the spacetime is asymptotically de Sitter in the future. Moreover, the limiting value of generalized entropy coincides with the de Sitter horizon entropy. We do not use the Einstein field equations in our proof, nor do we assume the existence of a positive cosmological constant. As such, asymptotic relaxation to a de Sitter phase can, in a precise sense, be thought of as cosmological equilibration.Comment: 43 pages 12 figures, v2: added references, fixed typos; v3: added a corollary in sec III, reworked parts of sec IV according to referee comments, added App B; v4: small formatting changes, updated to reflect PR

Geographical distribution of yellowfin tuna and skipjack catches in the Eastern Pacific Ocean, by quarters of the year, 1963-1966

ENGLISH: Logbook records of tuna vessels fishing in the eastern Pacific Ocean were used to prepare charts showing the distribution of yellowfin and skipjack tuna catches by 1-degree area, by quarter of the year, and by gear for the years 1963-1966. Recent changes in the geographical distribution of yellowfin catches are illustrated. The size composition of the U. S. tuna fleet is given, and recent changes are discussed. SPANISH: Los registros de los cuadernos de bitácora de los barcos atuneros que pescan en el Océano Pacifico oriental, se emplearon para preparar los gráficos que indican la distribuci6n de las capturas de atún aleta amarilla y de barrilete por área de 1 grado, por trimestre del ano y por aparejo de pesca para los anos de 1963-1966. Se ilustran los cambios recientes en la distribucion geográfica de las capturas de atún aleta amarilla. Se da la composición de tamaño de la flota atunera de los E. U. y se discuten los cambios recientes. (PDF contains 76 pages.

How to Recover a Qubit That Has Fallen Into a Black Hole

We demonstrate an algorithm for the retrieval of a qubit, encoded in spin angular momentum, that has been dropped into a no-firewall black hole. Retrieval is achieved analogously to quantum teleportation by collecting Hawking radiation and performing measurements on the black hole. Importantly, these methods only require the ability to perform measurements from outside the event horizon.Comment: 6 pages v2: modified protocol to discuss total angular momentum, corrected typos, added references v3: updated with referee feedbac

De Sitter Space as a Tensor Network: Cosmic No-Hair, Complementarity, and Complexity

We investigate the proposed connection between de Sitter spacetime and the MERA (Multiscale Entanglement Renormalization Ansatz) tensor network, and ask what can be learned via such a construction. We show that the quantum state obeys a cosmic no-hair theorem: the reduced density operator describing a causal patch of the MERA asymptotes to a fixed point of a quantum channel, just as spacetimes with a positive cosmological constant asymptote to de Sitter. The MERA is potentially compatible with a weak form of complementarity (local physics only describes single patches at a time, but the overall Hilbert space is infinite-dimensional) or, with certain specific modifications to the tensor structure, a strong form (the entire theory describes only a single patch plus its horizon, in a finite-dimensional Hilbert space). We also suggest that de Sitter evolution has an interpretation in terms of circuit complexity, as has been conjectured for anti-de Sitter space.Comment: 24 pages, 12 figures. Updated to be consistent with PRD versio

Coherent optical implementations of the fast Fourier transform and their comparison to the optical implementation of the quantum Fourier transform

Optical structures to implement the discrete Fourier transform (DFT) and fast Fourier transform (FFT) algorithms for discretely sampled data sets are considered. In particular, the decomposition of the FFT algorithm into the basic Butterfly operations is described, as this allows the algorithm to be fully implemented by the successive coherent addition and subtraction of two wavefronts (the subtraction being performed after one has been appropriately phase shifted), so facilitating a simple and robust hardware implementation based on waveguided hybrid devices as employed in coherent optical detection modules. Further, a comparison is made to the optical structures proposed for the optical implementation of the quantum Fourier transform and they are shown to be very similar

Understanding adoption of big data analytics in China: from organizational users perspective

Big data is a recent technology employed by companies to gain a competitive advantage. The investment of big data technologies in the USA was estimated at more than 30 billion USD in 2016. However, the investment of big data technologies in China was relatively small in 2016. Grounded in the Technology-Organization-Environment (TOE) framework, this study identifies the main factors affecting the organizational adoption of big data in China. The results can provide useful indicators for industries to utilize big data for a more productive business

Measurement Techniques for Transmit Source Clock Jitter for Weak Serial RF Links

Techniques for filtering clock jitter measurements are developed, in the context of controlling data modulation jitter on an RF carrier to accommodate low signal-to-noise ratio thresholds of high-performance error correction codes. Measurement artifacts from sampling are considered, and a tutorial on interpretation of direct readings is included