RRS James Cook Cruise 30, 26 Dec 2008-30 Jan 2009. Antarctic Deep Water Rates of Export (ANDREX)

This report describes scientific activities on RRS James Cook cruise 30, “ANDREX”, westwards from 30°E and in the vicinity of latitude 60°S, between late December 2008 and late January 2009. The cruise was terminated about halfway through by a medical emergency. Hydrographic work comprised 27 CTD/LADCP stations. Water samples were captured for measurement of salinity, dissolved oxygen, inorganic nutrients, oxygen isotope fraction, chlorofluorocarbons and sulphur hexafluoride, dissolved inorganic carbon and alkalinity, helium / tritium / noble gases and radiocarbon. Underway measurements comprised navigation, currents (ADCP), meteorology, and sea surface temperature and salinity. The remainder of the hydrographic section was executed a year later on RRS James Clark Ross, cruise JR239

Close Approach during Hard Binary--Binary Scattering

We report on an extensive series of numerical experiments of binary--binary scattering, analysing the cross--section for close approach during interactions for a range of hard binary parameters of interest in globular cluster cores. We consider the implied rate for tidal interactions for different globular clusters and compare our results with previous, complementary estimates of stellar collision rates in globular clusters. We find that the collision rate for binary--binary encounters dominates in low density clusters if the binary fraction in the cluster is larger than $0.2$ for wide main--sequence binaries. In dense clusters binary--single interactions dominate the collision rate and the core binary fraction must be \ltorder 0.1 per decade in semi--major axis or too many collisions take place compared to observations. The rates are consistent if binaries with semi--major axes $\sim 100 AU$ are overabundant in low density clusters or if breakup and ejection substantially lowers the binary fraction in denser clusters. Given reasonable assumptions about fractions of binaries in the cores of low density clusters such as NGC~5053, we cannot account for all the observed blue stragglers by stellar collisions during binary encounters, suggesting a substantial fraction may be due to coalescence of tight primordial binaries.Comment: 13 pages including 13 ps figures. MNRAS in pres

The Optimal Single Copy Measurement for the Hidden Subgroup Problem

The optimization of measurements for the state distinction problem has recently been applied to the theory of quantum algorithms with considerable successes, including efficient new quantum algorithms for the non-abelian hidden subgroup problem. Previous work has identified the optimal single copy measurement for the hidden subgroup problem over abelian groups as well as for the non-abelian problem in the setting where the subgroups are restricted to be all conjugate to each other. Here we describe the optimal single copy measurement for the hidden subgroup problem when all of the subgroups of the group are given with equal a priori probability. The optimal measurement is seen to be a hybrid of the two previously discovered single copy optimal measurements for the hidden subgroup problem.Comment: 8 pages. Error in main proof fixe

RRS James Clark Ross Cruise 67, 19 Nov-17 Dec 2002. Drake Passage repeat hydrography: WOCE Southern Repeat Section 1b – Burdwood Bank to Elephant Island

This report describes the seventh repeat hydrography section across Drake Passage, first established during the World Ocean Circulation Experiment. Thirty CTD/LADCP stations were carried out across the 753 km section from Burdwood Bank to Elephant Island, plus one test station, one station in Drake Passage to provide sound speed information for concurrent geophysical activities, and one station at the Rothera Time Series (RaTS) site, just off Biscoe Wharf at Rothera. Maximum station spacing on thesection was 33 km, with stations closer together on the continental shelves. Water samples were drawn for salinity analysis, for subsequent CTD conductivity calibration. The LADCP was a new 2-instrument setup comprising upward– and downward–looking RD Instruments Workhorse ADCPs. The CTD was a SeaBird 911plus with dual temperature and conductivity sensors. Various underway measurements included navigation, vessel-mounted ADCP, sea surface temperature and salinity, water depth and meteorological parameters

RRS James Clark Ross Cruise 81, 18 Dec 2002-02 Jan 2003. Drake Passage repeat hydrography: WOCE Southern Repeat Section 1b – Elephant Island to Burdwood Bank

This report describes the eighth repeat hydrography section across Drake Passage, first established during the World Ocean Circulation Experiment. Thirty CTD/LADCP stations were carried out across the 753 km section from Elephant Island to Burdwood Bank, plus one test station and one station at the Rothera Time Series (RaTS) site, just off Biscoe Wharf at Rothera. Maximum station spacing on thesection was 33 km, with stations closer together on the continental shelves. Water samples were drawn for salinity analysis, for subsequent CTD conductivity calibration. Samples were also drawn for analysis of oxygen isotope fraction ?18O, for later analysis back at Southampton Oceanography Centre. The LADCP comprised a single downward-looking RD Instruments Workhorse ADCP. The CTD was a SeaBird 911plus with dual conductivity and temperature sensors. Various underway measurements included navigation, vessel-mounted ADCP, sea surface temperature and salinity, water depth and meteorological parameters

David Shaw in the continuum of press self-criticism

David Shaw is the Los Angeles Times press critic, the only newspaper writer in the United States who devotes his full time to researching and writing criticisms and explanatory articles about broad issues affecting the press and the public. In addition to calling attention to bias, sensationalism, arrogance, and unresponsiveness in the press, Shaw has sparked internal criticism from his colleagues at the Times; At a time of declining public confidence in the media, Shaw asserts that the press has a duty to explain itself and engage in public self-criticism: The only public institution the press does not regularly scrutinize is the press; This study identifies the most prominent and insightful press self-critics in U.S. history and traces the development of their critical themes. Shaw\u27s eighteen and a half years of press criticism is then examined and found to continue many of the critical themes from history

Why Waste Water? A Bifurcated Proposal for Managing, Utilizing, and Profiting from Coalbed Methane Discharged Water

The Coalbed Methane ( CBM ) industry is booming throughout the Rocky Mountain West, creating a relatively clean energy alternative, much needed jobs in the region, and a deluge of water pumped from the ground in connection with CBM capture. In order to free the valuable natural gas, companies must first pump out substantial quantities of subsurface water holding the pressurized gas in place. This water varies in quality, from perfectly useful, potable water to poor-quality water with the potential to destroy the surrounding environment. Correspondingly, disposal of the pumped water varies from simply releasing it into streams surrounding the CBM pads to reinjecting it back into subterranean aquifers. Most importantly, aside from the imprecise, general protections of the Clean Water Act, no current legal system covers this sizeable new source of water. This Comment advocates using the framework of the Clean Water Act to distinguish between poor- and high-quality water, with an emphasis on creating a comprehensive regional system to maximize the utility and profitability of the highquality water. More specifically, the Comment uses the Powder River Basin of Wyoming as a case-study to argue that states should implement a water bank or water storage system that collects high-quality water discharged from CBM wells and sells it on an open market. Profits from such water sales would first go towards paying infrastructure and operating costs, followed by a significant portion towards environmental restitution of the areas impacted by the CBM industry. The remaining profits would be returned to the CBM companies, providing an incentive to participate in the program and even clean some of the poor-quality water pre-viously reinjected in order to make that water eligible for the program. By establishing such a program, all parties involved in the CBM process stand to benefit, including the state, the energy companies, the environmentalists, and the residents forced to endure the negative externalities of CBM mining

Quantum operations that cannot be implemented using a small mixed environment

To implement any quantum operation (a.k.a. ``superoperator'' or ``CP map'') on a d-dimensional quantum system, it is enough to apply a suitable overall unitary transformation to the system and a d^2-dimensional environment which is initialized in a fixed pure state. It has been suggested that a d-dimensional environment might be enough if we could initialize the environment in a mixed state of our choosing. In this note we show with elementary means that certain explicit quantum operations cannot be realized in this way. Our counterexamples map some pure states to pure states, giving strong and easily manageable conditions on the overall unitary transformation. Everything works in the more general setting of quantum operations from d-dimensional to d'-dimensional spaces, so we place our counterexamples within this more general framework.Comment: LATEX, 8 page

A tutorial task and tertiary courseware model for collaborative learning communities

RAED provides a computerised infrastructure to support the development and administration of Vicarious Learning in collaborative learning communities spread across multiple universities and workplaces. The system is based on the OASIS middleware for Role-based Access Control. This paper describes the origins of the model and the approach to implementation and outlines some of its benefits to collaborative teachers and learners