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

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

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 $\frac{\pi}{2}$ pulse of $1.3 \pm 0.1 \times 10^{-4}$ 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 $4.7 \pm 0.3 \times 10^{-3}$ 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 complex quantum dynamics with a scalable NMR information processor

We present experimental results on the measurement of fidelity decay under contrasting system dynamics using a nuclear magnetic resonance quantum information processor. The measurements were performed by implementing a scalable circuit in the model of deterministic quantum computation with only one quantum bit. The results show measurable differences between regular and complex behaviour and for complex dynamics are faithful to the expected theoretical decay rate. Moreover, we illustrate how the experimental method can be seen as an efficient way for either extracting coarse-grained information about the dynamics of a large system, or measuring the decoherence rate from engineered environments.Comment: 4pages, 3 figures, revtex4, updated with version closer to that publishe

Word-level Symbolic Trajectory Evaluation

Symbolic trajectory evaluation (STE) is a model checking technique that has been successfully used to verify industrial designs. Existing implementations of STE, however, reason at the level of bits, allowing signals to take values in {0, 1, X}. This limits the amount of abstraction that can be achieved, and presents inherent limitations to scaling. The main contribution of this paper is to show how much more abstract lattices can be derived automatically from RTL descriptions, and how a model checker for the general theory of STE instantiated with such abstract lattices can be implemented in practice. This gives us the first practical word-level STE engine, called STEWord. Experiments on a set of designs similar to those used in industry show that STEWord scales better than word-level BMC and also bit-level STE.Comment: 19 pages, 3 figures, 2 tables, full version of paper in International Conference on Computer-Aided Verification (CAV) 201

Alliances Versus Federations: An Analysis with Military and Economic Capabilities Distinguished

This essay explores the distinction between federations and alliances and asks the question: When will states choose to federate rather than ally? William Riker (1964) argues that a necessary condition for a federal state's formation is that those offering the federal bargain must seek to "expand their territorial control, usually either to meet an external military or diplomatic threat or to prepare for military or diplomatic aggression and aggrandizement." This argument, though, fails to ask why states sometimes respond to threats by forming federations and at other times by forming alliances. Here, after assuming that states have initial endowments of military and economic resources, where economic resources enter utility functions directly and a.re what states maximize and where military capability influences preference only insofar as it determines a state's ability to counter threats, we offer a. multi-stage game-theoretic model in which states may be compelled to divert economic resources to military spending. Alliances, in turn, are self-enforcing coalitions designed to augment a state's offensive or defensive capabilities. Federations, which serve the same ends as alliances, a.re coalitions that need to be enforced by the "higher authority" established when the federation is formed. Our operating assumption is that states seek to form a. federation in lieu of an alliance if and only if (1) a stable alliance partition does not exist or, if one exists, it is dominated by an unstable partition and (2) if the cost of the loss of sovereignty to each state in the federation is offset by the gains from joining it, relative to what that state secures as its security value

Notes on Constitutional Change in the ROC: Presidential versus Parliamentary Government

The debate over constitutional reform has moved to center stage in Taiwan, with a focus on two issues: the choice of presidential versus parliamentary government and a determination of the ultimate role of the National Assembly. These two issues, in turn, are linked by a third -- whether the president ought to be elected indirectly by the National Assembly or directly in a mass popular vote. Of these issues, though, the choice between a presidential and a parliamentary system is central, because it requires that we consider the methods whereby chief executives and legislators are elected and, correspondingly, the role of the National Assembly. Beginning, then, with the issue of presidential versus parliamentary government, this essay argues that the most commonly cited arguments over the advisability of choosing one or the other of these two forms are, for the most part, theoretically meaningless and are largely rhetorical devices for rationalizing prejudices about preferred governmental structures and the state's role. Consequently, we attempt here to provide a more useful set of criteria with which to evaluate reform in general and the choice between presidential and parliamentary government in particular. We conclude that although the choice between presidential and parliamentary forms is important, equal attention should be given to the methods whereby a president and the legislature are elected. It is these institutional parameters that determine the character of political parties in Taiwan, their ability to accommodate any mainlander-native Taiwanese conflict, and the likelihood that executive and legislative branches will formulate coherent domestic and international policy

Field trials of a NASA-developed mobile satellite terminal

Various field trials have been performed to validate and optimize the technologies developed by the Mobile Satellite Experiment (MSAT-X). For each of the field experiments performed, a brief description of the experiment is provided, followed by a summary of the experimental results. Emphasis is placed on the two full scale land mobile and aeronautical mobile experiments. Experiments planned for the near future are also presented

The Geographical Imperatives of the Balance of Power in 3-Country Systems

This essay extends a cooperative game-theoretic model of balance of power in anarchic international systems to include considerations of the asymmetry which geography occasions in the offensive and defensive capabilities of countries. The two substantive ideas which concern us are a formalization of the notion of a "balancer" and that of a "central power." What we show is that in stable systems, only specific countries (such as Britain in the 18th and the 19th centuries) can play the role of balancer, and that the strategic imperatives of a central country (e.g., Germany in the period 1871-1945) differ in important ways from those of "peripheral" countries

Efficient Symmetry Reduction and the Use of State Symmetries for Symbolic Model Checking

One technique to reduce the state-space explosion problem in temporal logic model checking is symmetry reduction. The combination of symmetry reduction and symbolic model checking by using BDDs suffered a long time from the prohibitively large BDD for the orbit relation. Dynamic symmetry reduction calculates representatives of equivalence classes of states dynamically and thus avoids the construction of the orbit relation. In this paper, we present a new efficient model checking algorithm based on dynamic symmetry reduction. Our experiments show that the algorithm is very fast and allows the verification of larger systems. We additionally implemented the use of state symmetries for symbolic symmetry reduction. To our knowledge we are the first who investigated state symmetries in combination with BDD based symbolic model checking