4,963 research outputs found

    Genes, geología y biodiversidad: diversidad de la fauna y flora de la isla de Gran Canaria

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    High levels of floral and faunal diversity in the Canary Islands have attracted much attention to the archipelago for both evolutionary and ecological study. Among the processes that have influenced the development of this diversity, the volcanic history of each individual island must have played a pivotal role. The central island of Gran Canaria has a long geological history of approximately 15 million years that was interrupted by violent volcanism between 5.5 and 3 million years ago. Volcanic activity is thought to have been so great as to have made all plant and animal life virtually extinct, with survival being limited to some coastal species. The implication from this is that the higher altitude laurel forest and pine woods environments must have been re–established following the dramatic volcanic period. This paper reviews the evidence for this using recent molecular phylogenetic data for a number of plant and animal groups on the island of Gran Canaria, and concludes that there is general support for the hypotheses that the forest environments of Gran Canaria post–date the Roque Nublo eruptive period.La extensa diversidad de la flora y fauna de las Islas Canarias ha convertido el archipiélago en un centro de especial interés para los estudios sobre evolución y ecología. De entre los procesos que han influido en el desarrollo de esta diversidad, cabe destacar el importante papel que ha desempeñado la historia volcánica de cada una de las islas. La isla principal del archipiélago, Gran Canaria, tiene una larga historia geológica de aproximadamente unos 15 millones de años, que fue interrumpida por un violento volcanismo que tuvo lugar hace entre 5,5 y 3 millones de años. Se considera que la actividad volcánica fue de tal magnitud, que prácticamente extinguió toda la vida vegetal y animal de las islas, a excepción de unas pocas especies costeras que lograron sobrevivir. De ello puede deducirse que los entornos de mayor altitud, como los bosques de laureles y pinos, seguramente se reestablecieron tras el dramático período volcánico antes mencionado. En este trabajo, se revisa la evidencia de ello mediante el análisis de datos filogénicos moleculares recientes de una serie de grupos de plantas y animales de la isla de Gran Canaria, y se demuestra la validez general de la hipótesis que sostiene que los entornos forestales de Gran Canaria son posteriores al ciclo eruptivo de Roque Nublo

    Randomized benchmarking of single and multi-qubit control in liquid-state NMR quantum information processing

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    Being able to quantify the level of coherent control in a proposed device implementing a quantum information processor (QIP) is an important task for both comparing different devices and assessing a device's prospects with regards to achieving fault-tolerant quantum control. We implement in a liquid-state nuclear magnetic resonance QIP the randomized benchmarking protocol presented by Knill et al (PRA 77: 012307 (2008)). We report an error per randomized π2\frac{\pi}{2} pulse of 1.3±0.1×10−41.3 \pm 0.1 \times 10^{-4} with a single qubit QIP and show an experimentally relevant error model where the randomized benchmarking gives a signature fidelity decay which is not possible to interpret as a single error per gate. We explore and experimentally investigate multi-qubit extensions of this protocol and report an average error rate for one and two qubit gates of 4.7±0.3×10−34.7 \pm 0.3 \times 10^{-3} for a three qubit QIP. We estimate that these error rates are still not decoherence limited and thus can be improved with modifications to the control hardware and software.Comment: 10 pages, 6 figures, submitted versio

    Characterization of eukaryotic microbial diversity in hypersaline Lake Tyrrell, Australia.

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    This study describes the community structure of the microbial eukaryotic community from hypersaline Lake Tyrrell, Australia, using near full length 18S rRNA sequences. Water samples were taken in both summer and winter over a 4-year period. The extent of eukaryotic diversity detected was low, with only 35 unique phylotypes using a 97% sequence similarity threshold. The water samples were dominated (91%) by a novel cluster of the Alveolate, Apicomplexa Colpodella spp., most closely related to C. edax. The Chlorophyte, Dunaliella spp. accounted for less than 35% of water column samples. However, the eukaryotic community entrained in a salt crust sample was vastly different and was dominated (83%) by the Dunaliella spp. The patterns described here represent the first observation of microbial eukaryotic dynamics in this system and provide a multiyear comparison of community composition by season. The lack of expected seasonal distribution in eukaryotic communities paired with abundant nanoflagellates suggests that grazing may significantly structure microbial eukaryotic communities in this system

    Technology for space shuttle main engine control checkout and diagnosis /GP 70-232/

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    Electronic control for space shuttle main engin

    Milk Yield of Dairy Buffaloes Supplemented with Yeast Solution and Yeast-fermented Cassava Pulp

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    Feed resource availability and quality are two of the major factors limiting dairy production in the Philippines. Utilization of microbial-based feed additives and agricultural by-products such as cassava pulp aided by fermentation technology can help provide the needed resource. This study aimed to determine the effect of activated yeast (Saccharomyces cerevisiae) solution (AYS) and yeast-fermented cassava pulp (YFCP) on milk production and feed cost-efficiency in dairy buffaloes. The study followed RCBD design using 63 dairy buffaloes at the Philippine Carabao Center in Ubay Stock Farm, Bohol. The average daily milk yield (ADMY) of buffaloes supplemented with 0.5L AYS and 1L AYS twice daily were greater than that of control buffaloes by 0.67L and 0.69L, respectively (P = 0.0039).On the other hand, the ADMY of buffaloes fed with YFCP and YFCP+AYS were greater than that of control buffaloes by 0.64 and 0.68L, respectively (P = 0.0320). Supplementation of AYS and feeding YFCP yielded the lowest cost per liter of milk produced at PhP 20.25 and PhP 16.24, respectively. It is recommended to supplement milking dairy buffaloes with AYS or feeding YFCP in areas with cassava pulp to increase feed resource, increase milk production and improve feed cost-efficiency thereby increasing significantly the farmer’s income

    Envelope from Miss Baker containing letters from George C. Parkinson, C. W. Emerson, Emeline B. Wells, and Lou Lewis

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    Letters of recommendation for Mercy Rachel Baker

    On the Hybrid Extension of CTL and CTL+

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    The paper studies the expressivity, relative succinctness and complexity of satisfiability for hybrid extensions of the branching-time logics CTL and CTL+ by variables. Previous complexity results show that only fragments with one variable do have elementary complexity. It is shown that H1CTL+ and H1CTL, the hybrid extensions with one variable of CTL+ and CTL, respectively, are expressively equivalent but H1CTL+ is exponentially more succinct than H1CTL. On the other hand, HCTL+, the hybrid extension of CTL with arbitrarily many variables does not capture CTL*, as it even cannot express the simple CTL* property EGFp. The satisfiability problem for H1CTL+ is complete for triply exponential time, this remains true for quite weak fragments and quite strong extensions of the logic

    Negative Quasi-Probability as a Resource for Quantum Computation

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    A central problem in quantum information is to determine the minimal physical resources that are required for quantum computational speedup and, in particular, for fault-tolerant quantum computation. We establish a remarkable connection between the potential for quantum speed-up and the onset of negative values in a distinguished quasi-probability representation, a discrete analog of the Wigner function for quantum systems of odd dimension. This connection allows us to resolve an open question on the existence of bound states for magic-state distillation: we prove that there exist mixed states outside the convex hull of stabilizer states that cannot be distilled to non-stabilizer target states using stabilizer operations. We also provide an efficient simulation protocol for Clifford circuits that extends to a large class of mixed states, including bound universal states.Comment: 15 pages v4: This is a major revision. In particular, we have added a new section detailing an explicit extension of the Gottesman-Knill simulation protocol to deal with positively represented states and measurement (even when these are non-stabilizer). This paper also includes significant elaboration on the two main results of the previous versio
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