Describing Sr2RuO4 superconductivity in a generalized Ginzburg--Landau theory

We propose a simple explanation of unconventional thermodynamical and magnetic properties observed for Sr2RuO4. Actually, our two-phase model of superconductivity, based on a straight generalization of the Ginzburg-Landau theory, does predict two jumps in the heat capacity as well as a double curve for the dependence of the critical temperature on an external magnetic field. Such theoretical previsions well agree with the currently available experimental data for Sr2RuO4Comment: revtex, 9 pages, 1 eps figur

Seabird bycatch in New Zealand trawl and longline fisheries, 1998-2004

Fisheries bycatch is a threatening process for populations of procellariiform seabirds, and is of particular importance for the conservation of albatross, an especially threatened group at a global scale. There is a high level ofendemism of albatross and petrels in New Zealand waters, and around one-third of the world's species of procellariiform seabirds breed in this area. Therefore, understanding the levels of mortality of these species in the New Zealand Exclusive Economic Zone is important for global conservation of the order. For New Zealand fisheries for the 1998-2004 fishing years, we estimated total seabird bycatch using data from scientific observers with model-based estimation procedures. Although sectors of the fishing activity were not evenly covered by observers, we were able to estimate seabird bycatch for large scale fisheries by vessel size (split at 28 m length), season, area and year. Approximately 5500 seabirds (credible interval between 2000 and 10 000) are estimated to be landed in New Zealand trawl and longline fisheries annually, as a result of interactions with fishing gear. Few data were available for the small vessels, thus estimates are highly uncertain. Mortalities are likely to be most common in trawl fisheries at approximately 2000-3000 seabirds annually, with the greatest contribution coming from large vessels. Around one half of these birds were albatross. For large surface longline vessels we estimated that fewer than 500 seabirds were killed annually during the main tuna fishing season. For large demersal vessels, seabird mortality was estimated to have decreased from around 1800 seabirds in 2001 to 600 seabirds in 2004. We report observed captures by species for each fishing method and area for the fishing years 1998-2004. Thirty-one species of Procellariiformes were identified during this period, over half of which are threatened species. For some species, such as White-chinned Petrel, Procellaria aequinoctialis and White-capped Albatross, 1halassarche steadi, several hundred individuals were caught. For 15 species, fewer than 10 individuals were identified. However, the unrepresentative deployment ofobserver coverage across fishery areas makes it difficult to interpret the conservation implications of species captures. A high proportion of the petrel species was observed caught primarily from areas surrounding their breeding sites while albatross were caught across breeding and non-breeding areas. Greatly improved observer sampling ratios, and studies of population status and trends, are needed to understand the conservation implications of the effects of New Zealand trawl and longline fishing mortalities on seabird populations

Ecologists need robust survey designs, sampling and analytical methods

1. Research that yields conflicting results rightly causes controversy. Where methodological weaknesses are apparent, there is ready opportunity for discord within the scientific community, which may undermine the entire study. 2. We use the debate about the role of dingoes Canis dingo in conservation in Australia as a case study for a phenomenon that is relevant to all applied ecologists, where conflicting results have been published in high quality journals and yet the problems with the methods used in these studies have led to significant controversy. 3. To alleviate such controversies, scientists need to use robust methods to ensure that their results are repeatable and defendable. To date, this has not occurred in Australia’s dingo debate due to the use of unvalidated indices that rely on unsupported assumptions. 4. We highlight the problems that poor methods have caused in this debate. We also reiterate our recommendations for practitioners, statisticians and researchers to work together to develop long-term, multi-site experimental research programmes using robust methods to understand the impacts of dingoes on mesopredators. 5. Synthesis & applications. Incorporating robust methods and appropriate experimental designs are needed to ensure that conservation actions are appropriately focused and are supported with robust results. Such actions will go a long way towards resolving the debate about the role of dingoes in conservation in Australia, and other, ecological debates

Magnetic properties of two-phase superconductors

We have recently proposed a theoretical model for superconductors endowed with two distinct superconducting phases, described by two scalar order parameters which condensate at different critical temperatures. On analyzing the magnetic behavior of such systems, we have found some observable differences with respect to the case of ordinary Ginzburg-Landau superconductors. In particular, at low temperature the London penetration length is strongly reduced and the Ginzburg-Landau parameter k becomes a function of temperature. By contrast, in the temperature region between the two phase transitions k is constant and the system is a type-I or a type-II superconductor depending on the ratio between the critical temperatures.Comment: revtex, 5 pages, 1 eps figur

Second discontinuity in the specific heat of two-phase superconductors

The recently proposed theoretical model of superconductors endowed with two distinct superconducting phases and critical temperatures is further analyzed by introducing two distinct order parameters, described by two scalar fields which condensate at different temperatures. We find some deviations in basic thermodynamical quantities with respect to the Ginzburg-Landau one-phase superconductors. In particular, by contrast to the usual case where only one jump in specific heat takes place at the normal-superconductor transition temperature, we actually predict an additional discontinuity for C_V when passing from a superconducting phase to the other one.Comment: revtex, 4 pages, 1 figur

Properties of charmonium in lattice QCD with 2+1 flavors of improved staggered sea quarks

We use the dynamical gluon configurations provided by the MILC collaboration in a study of the charmonium spectrum and psi leptonic width. We examine sea quark effects on mass splitting and on the leptonic decay matrix element for light masses as low as m_s/5, while keeping the strange quark mass fixed and the lattice spacing nearly constant.Comment: Lattice2003(heavy

The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA

We present the SCUBA Legacy Catalogues, two comprehensive sets of continuum maps (and catalogues) using data at 850 microns and 450 microns of the various astronomical objects obtained with the Submillimetre Common User Bolometer Array (SCUBA). The Fundamental Map Dataset contains data only where superior atmospheric opacity calibration data were available. The Extended Map Dataset is comprised of data regardless of the quality of the opacity calibration. Each Dataset contains 1.2 degree x 1.2 degree maps at locations where data existed in the JCMT archive, imaged using the matrix inversion method. The Fundamental Dataset is comprised of 1423 maps at 850 microns and 1357 maps at 450 microns. The Extended Dataset is comprised of 1547 maps at 850 microns. Neither Dataset includes high sensitivity, single chop SCUBA maps of "cosmological fields" nor solar system objects. Each Dataset was used to determine a respective Object Catalogue, consisting of objects identified within the respective 850 micron maps using an automated identification algorithm. The Fundamental and Extended Map Object Catalogues contain 5061 and 6118 objects respectively. Objects are named based on their respective J2000 position of peak 850 micron intensity. The Catalogues provide for each object the respective maximum 850 micron intensity, estimates of total 850 micron flux and size, and tentative identifications from the SIMBAD Database. Where possible, the Catalogues als provide for each object its maximum 450 micron intensity and total 450 micron flux, and flux ratios. Data products, machine-readable tables and a full version of the paper can be retrieved at http://www.cadc.hia.nrc.gc.ca/community/scubalegacy .Comment: 41 pages, 17 figures in JPEG format; to be published in ApJ