Constructing\u27 Fisheries Management: A Values Perspective

This paper applies a social constructionist position to an understanding of the nature of fisheries management policy. It argues that both the way in which we view nature and the way in which we view such natural resources of the fishery are socially constructed in terms of particular value orientations and the interests that these represent. In particular, it examines the value orientations related to the social construction of the fishery as a biological, social, or economic resource, as well as the social constructions involved in regarding the fishery as either common property or a common heritage. It also argues that perspectives of the fishery in terms of sustainable development adopt a utilitarian approach to nature rather than an environment centred approach. The paper concludes with a brief consideration of the way in which these social constructions were part of the 1995 dispute overthe turbot fishery off Canada\u27s east coast and considers the extent to which such social construction have implications for Canada\u27s future fisheries management policy

Determination of Chlorides in Petroleum.

n/

On the Synthesis and Characterization of the Optical Properties of Europium- and Ruthenium-Doped Sol-Gel-Derived Materials and Sodium Sulfates

Chemistr

Passive, broadband and low-frequency suppression of laser amplitude noise to the shot-noise limit using hollow-core fibre

We use hollow-core fibre to preserve the spectrum and temporal profile of picosecond laser pulses in CBD to suppress 2.6 dB of amplitude noise at MHz noise frequencies, to within 0.01 dB of the shot-noise limit. We provide an enhanced version of the CBD scheme that concatenates circuits to suppress over multiple frequencies and over broad frequency ranges --- we perform a first demonstration that reduces total excess amplitude noise, between 2 - 6 MHz, by 85%. These demonstrations enable passive, broad-band, all-guided fibre laser technology operating at the shot-noise limit.Comment: 8 pages, 8 figure

Partial metrizability in value quantales

[EN] Partial metrics are metrics except that the distance from a point to itself need not be 0. These are useful in modelling partially defined information, which often appears in computer science. We generalize this notion to study “partial metrics” whose values lie in a value quantale which may be other than the reals. Then each topology arises from such a generalized metric, and for each continuous poset, there is such a generalized metric whose topology is the Scott topology, and whose dual topology is the lower topology. These are both corollaries to our result that a bitopological space is pairwise completely regular if and only if there is such a generalized metric whose topology is the first topology, and whose dual topology is the second.This author wishes to acknowledge support for this research from the EPSRC of the United Kingdom (grant GR/S07117/01), and from the City University of New York (PSCCUNY grant 64472-00 33).Kopperman, RD.; Matthews, S.; Pajoohesh, H. (2004). Partial metrizability in value quantales. Applied General Topology. 5(1):115-127. https://doi.org/10.4995/agt.2004.2000SWORD1151275

Compensating for Beamsplitter Asymmetries in Quantum Interference Experiments

The visibility of the quantum interference "dip" seen in the Hong-Ou-Mandel experiment is optimized when a symmetric 50/50 beamsplitter is used in the interferometer. Here we show that the reduction in visibility caused by an asymmetric beamsplitter can be compensated by manipulating the polarization states of the two input photons. We experimentally demonstrate this by using a highly asymmetric 10/90 beamsplitter, and converting an initial dip visibility of 22% to a compensated value of 99%.Comment: 3 pages, 4 figure

A simple scheme for expanding photonic cluster states for quantum information

We show how an entangled cluster state encoded in the polarization of single photons can be straightforwardly expanded by deterministically entangling additional qubits encoded in the path degree of freedom of the constituent photons. This can be achieved using a polarization--path controlled-phase gate. We experimentally demonstrate a practical and stable realization of this approach by using a Sagnac interferometer to entangle a path qubit and polarization qubit on a single photon. We demonstrate precise control over phase of the path qubit to change the measurement basis and experimentally demonstrate properties of measurement-based quantum computing using a 2 photon, 3 qubit cluster state

Calculating Unknown Eigenvalues with a Quantum Algorithm

Quantum algorithms are able to solve particular problems exponentially faster than conventional algorithms, when implemented on a quantum computer. However, all demonstrations to date have required already knowing the answer to construct the algorithm. We have implemented the complete quantum phase estimation algorithm for a single qubit unitary in which the answer is calculated by the algorithm. We use a new approach to implementing the controlled-unitary operations that lie at the heart of the majority of quantum algorithms that is more efficient and does not require the eigenvalues of the unitary to be known. These results point the way to efficient quantum simulations and quantum metrology applications in the near term, and to factoring large numbers in the longer term. This approach is architecture independent and thus can be used in other physical implementations