Strain comparisons in aquaculture species: a manual

When different strains or breeds of a particular species are available, the best choice is seldom immediately obvious for producers. Scientists are also interested in the relative performance of different strains because it provides a basis for recommendations to producers and it often stimulates the conduct of work aimed at unraveling the underlying biological mechanisms involved in the expression of such differences. Hence, strain or breed comparisons of some sort are frequently conducted. This manual is designed to provide general guidelines for the design of strain comparison trials in aquaculture species. Example analyzes are provided using SAS and SPSS. The manual is intended to serve a wide range of readers from developing countries with limited access to information. The users, however, are expected to have a basic knowledge of quantitative genetics and experience in statistical methods and data analysis as well as familiarity with computer software. The manual mainly focuses on the practical aspects of design and data analysis, and interpretation of results

Captives or Prisoners: Society and Obligation in Medieval Iberia

There are important differences between the medieval captive and the modern prisoner of war. While, in each instance, their societies desire their liberation and restoration, the medieval captive lacked the framework and protection of international law and so had to rely upon the charity of friends and neighbors and the self-interest of their captors. Medieval Spanish society, nonetheless, endeavored to facilitate these exchanges by promoting filial obligations, protecting a captive’s property and establishing mechanisms to facilitate exchanges and ransoming. In addition, Christian and Muslim rulers included captives among the items to be negotiated during periods of truce

Kautilya, Sisyphus and development studies : on policy, administration and well-being

Twenty-three centuries ago, over five times the span of years since Niccolo Machiavelli wrote The Prince and The Discourses, an Indian Brahmin composed a political treatise on government called theArthasastra. That treatise byKautilya - or Chanakya, as he is sometimes known - synthesized behavioural principles and propositions which have remarkable relevance to development studies. As I searched for a cornerstone on which to base myinaugural lecture here at the ISS, I recalled my ,I excitement thirty years ago on entering a world of ideas and applications beyond the confines of Euro-America, I was then an undergraduate student at the University of Minnesota studying political science, French and history, and I encountered Kautilya's Arthasastra as well as Ibn Khaldun's Muqaddima or "Prolegomenon to History" long before I was even selected to be an exchange-student at Osmania University in Hyderabad, India. This afternoon I am going to share some of those early thoughts, tempered (of course) with a few decades of my experiences on various continents in various capacities. An advantage of this perhaps unorthodox approach is that it allowsme to raise questions and proposals about public policy and administration in their broader, world-wide context through the ages rather than being afflicted - as is so often the case - with what might be called "current-events-itis" and excessive concern with the immediate here and now

Sir John Cornforth AC CBE FRS: his synthetic work

Sir John Cornforth’s work on the synthesis of cholesterol and penicillamine, on the chemistry of oxazoles, the stereochemistry of the synthesis of alkenes, the synthesis of abscisic acid and of dibenzophospholes as mimics of enzyme action, is reviewed

Water quality impacts of mechanical shredding of aquatic macrophytes

We examined the impacts of mechanical shredding (i.e.. shredding plants and leaving biomass in the system) of the water chestnut (Trapa natans) on water quality and nutrient mobilization in a control and experimental site in Lake Champlain (Vermont-New York). A 1-ha plot was mechanically shredded within 1 h on 26 July, 1999. Broken plant material was initially concentrated on the lake surface of the experimental station after shredding, and was noticeable on the lake surface for 19 d. Over a two week period after shredding. concentrations of total nitrogen (N) and phosphorus (P), and soluble reactive P increased in the lower water column of the experimental station, coinciding with decomposition of water chestnut. Sediments in the control and experimental stations exhibited vet-v low rates of N and P release and could not account for increases in nutrient concentrations in the water column after mechanical shredding. Shredded plant material deployed in mesh bags at the experimental station lost similar to 70% of their total mass, and 42%, N and 70% P within 14 d. indicating Substantial nutrient mobilization via autolysis and decomposition. Chlorophyll a concentrations increased to 35 g/L at the experimental station on day 7 after shredding, compared to a concentration of 4 g/L at the control station. suggesting uptake of mobilized nutrients by phytoplankton. Disruption Of the Surface canopy of water chestnut by shredding was associated with marked increases in turbidity and dissolved oxygen, suggesting increased mixing at the experimental site

Extrinsic Curvature and the Einstein Constraints

The Einstein initial-value equations in the extrinsic curvature (Hamiltonian) representation and conformal thin sandwich (Lagrangian) representation are brought into complete conformity by the use of a decomposition of symmetric tensors which involves a weight function. In stationary spacetimes, there is a natural choice of the weight function such that the transverse traceless part of the extrinsic curvature (or canonical momentum) vanishes.Comment: 8 pages, no figures; added new section; significant polishing of tex

Hydrodynamic Modes for Granular Gases

The eigenfunctions and eigenvalues of the linearized Boltzmann equation for inelastic hard spheres (d=3) or disks (d=2) corresponding to d+2 hydrodynamic modes, are calculated in the long wavelength limit for a granular gas. The transport coefficients are identified and found to agree with those from the Chapman-Enskog solution. The dominance of hydrodynamic modes at long times and long wavelengths is studied via an exactly solvable kinetic model. A collisional continuum is bounded away from the hydrodynamic spectrum, assuring a hydrodynamic description at long times. The bound is closely related to the power law decay of the velocity distribution in the reference homogeneous cooling state

Assessing Patterns of Barn Owl \u3cem\u3eTyto alba\u3c/em\u3e Occupancy from Call Broadcast Surveys

Owing to habitat loss, changes in farming practices, urbanization, and high mortality through vehicle collisions, barn owls Tyto alba are a species of conservation concern in portions of their range. This species can be secretive and difficult to survey, particularly away from breeding sites, so factors related to barn owl occurrence often remain unknown. We conducted nighttime broadcast surveys for barn owls during the early- and post-breeding seasons and used an occupancy modeling framework to understand how factors related to landcover, landscape features, and human development related to occupancy in southern Idaho, USA. We also assessed the effectiveness of using broadcasts of conspecific vocalizations to improve owl detection. Barn owls were detected during 52 of 666 point counts and at 37 of 222 locations in the early-breeding season and 50 of 198 point counts and 31 of 66 locations in the post-breeding season. The probability of detecting barn owls was 0.32 ± 0.06 (SE) and 0.45 ± 0.07 (SE) during the early- and post-breeding seasons, respectively. Based on analysis within 1-km buffers surrounding point-count locations, occupancy in the early-breeding season increased with percentage of crop coverage and presence of trees and decreased with background noise. Post-breeding season occupancy increased with stream length and decreased with area of development and distance from the Snake River, a major geologic feature that likely provided roost sites in its canyon walls and riparian woodlands and a dispersal corridor for juveniles. Broadcast of barn owl vocalizations increased detection probability as much as nine times. Thus, incorporating call broadcast into future barn owl surveys should help investigators reduce false conclusions of absence. Ultimately, understanding factors influencing occupancy of barn owls will facilitate effective conservation, especially in light of population pressures related to factors such as roadway mortality and loss of nesting sites with increased urbanization