Sex-specific growth and mortality, spawning season, and female maturation of the stripey bass (Lutjanus carponotatus) on the Great Barrrier Reef

Sex-specific demography and reproductive biology of stripey bass (Lutjanus carponotatus) (also known as Spanish flag snapper, FAO) were examined at the Palm and Lizard island groups, Great Barrier Reef (GBR).Total mortality rates were similar between the sexes. Males had larger L∞ at both island groups and Lizard Island group fish had larger overall L∞. Female:male sex ratios were 1.3 and 1.1 at the Palm and Lizard island groups, respectively. The former is statistically different from 1, but is unlikely significantly different in a biological sense. Females matured on average at 2 years of age and 190 mm fork length at both locations. Female gonadal lipid body indices peaked from August through October, preceding peak gonadosomatic indices in October, November, and December that were twice as great as in any other month. However, ovarian staging revealed 50% or more ovaries were ripe from September through February, suggesting a more protracted spawning season and highlighting the different interpretations that can arise between gonad weight and gonad staging methods. Gonadosomatic index increases slightly with body size and larger fish have a longer average spawning season, which suggests that larger fish produce greater relative reproductive output. Lizard Island group females had ovaries nearly twice as large as Palm Island group females at a given body size. However, it is unclear whether this reflects spatial differences akin to those observed in growth or effects of sampling Lizard Island group fish closer to their date of spawning. These results support an existing 250 mm minimum size limit for L. carponotatus on the GBR, as well as the timing of a proposed October through December spawning closure for the fishery. The results also caution against assessing reef-fish stocks without reference to sex-, size-, and location-specific biological traits.

Gum arabic, carrageenan of various types and sago palm starch as binders in prawn diets

An experiment was undertaken in order to investigate the use of sago palm starch, gum arabic and carrageenans as binders in prawn diets. Water stability data are presented; EPT-2 carrageenan was found to be the best binder for both steamed and unsteamed pellets.

Spray combustion characteristics of palm biodiesel

The potential of palm methyl esters (PME) as an alternative fuel for gas turbines is investigated using a swirl burner. The main air flow is preheated to 623 K, and a swirling spray flame is established at atmospheric pressure. The spray combustion characteristics of PME are compared to diesel and Jet-A1 fuel under the same burner power output of 6 kW. Investigation of the fuel atomizing characteristics using phase Doppler anemometry (PDA) shows that most droplets are distributed within the flame reaction zone region. PME droplets exhibit higher Sautermean diameter (SMD) values than baseline fuels, and thus higher droplet penetration length and longer evaporation timescales. The PME swirl flame presents a different visible flame reaction zone while combusting with low luminosity and produces no soot. NO x emissions per unit mass of fuel and per unit energy are reduced by using PME relative to those of conventional fuels. © 2012 Copyright Taylor and Francis Group, LLC.

Palm frond biochar production and characterisation

Palm oil has been the world's main source of oil and fats since 2004, producing over 45 million tonnes in 2009. Malaysia alone has over 4·5 million hectares planted with oil palm and, based on common practice, ~300 palm fronds are pruned per hectare per year. This agricultural waste is currently either being used as roughage feed or, more frequently, being left between rows of palm trees to prevent soil erosion, or for nutrient recycling purposes. This paper proposes an alternative use for palm frond as a source of biochar. A traditional method commonly use by gardeners in Malaysia to improve soil fertility was used to produce the biochar. A shallow earth pit was dug in the ground for the carbonisation process. The process is described and the impact of carbonisation on the earth wall is analysed and presented. The process was later re-assessed by using TGA-FTIR. Most of the hemicelluloses had fully disintegrated, but the depolymerisation of the cellulose was still incomplete at the carbonisation temperature. Most of the lignin aromatic structure was still present in the biochar. The carbonisation process was repeated in the laboratory and biochar was characterised by using BET, SEM and FTIR. An adsorption isotherm study was conducted and the experimental data were fitted to the Langmuir model. The model predicted Pb2+ adsorption rates of 83·3 mg/g, Cu2+ 41·4 mg/g, Ni2+ 13·0 mg/g and Zn2+ 19·7 mg/g. Copyright © The Royal Society of Edinburgh 2012.

The date and authorship of Culhwch ac Olwen: a reassessment

Rodway, S. (2005). The date and authorship of Culhwch ac Olwen: a reassessment. Cambrian Medieval Celtic Studies. 49, pp.21-44. RAE2008

Letter to nephew, no date.

Handwritten letter from Daniel D. Whedon to nephew, Daniel Avery Whedon. Not dated.

Earliness penalties on a single machine subject to precedence constraints: SLK due date assignment

The paper considers the single machine due date assignment and scheduling problems with n jobs in which the due dates are to be obtained from the processing times by adding a positive slack q. A schedule is feasible if there are no tardy jobs and the job sequence respects given precedence constraints. The value of q is chosen so as to minimize a function ϕ(F,q) which is non-decreasing in each of its arguments, where F is a certain non-decreasing earliness penalty function. Once q is chosen or fixed, the corresponding scheduling problem is to find a feasible schedule with the minimum value of function F. In the case of arbitrary precedence constraints the problems under consideration are shown to be NP-hard in the strong sense even for F being total earliness. If the precedence constraints are defined by a series-parallel graph, both scheduling and due date assignment problems are proved solvable in time, provided that F is either the sum of linear functions or the sum of exponential functions. The running time of the algorithms can be reduced to if the jobs are independent. Scope and purpose We consider the single machine due date assignment and scheduling problems and design fast algorithms for their solution under a wide range of assumptions. The problems under consideration arise in production planning when the management is faced with a problem of setting the realistic due dates for a number of orders. The due dates of the orders are determined by increasing the time needed for their fulfillment by a common positive slack. If the slack is set to be large enough, the due dates can be easily maintained, thereby producing a good image of the firm. This, however, may result in the substantial holding cost of the finished products before they are brought to the customer. The objective is to explore the trade-off between the size of the slack and the arising holding costs for the early orders.

Single machine scheduling and due date assignment under series-parallel precedence constraints

We consider a single machine due date assignment and scheduling problem of minimizing holding costs with no tardy jobs tinder series parallel and somewhat wider class of precedence constraints as well as the properties of series-parallel graphs.

A fully polynomial approximation scheme for the single machine weighted total tardiness problem with a common due date

We develop a fully polynomial-time approximation scheme (FPTAS) for minimizing the weighted total tardiness on a single machine, provided that all due dates are equal. The FPTAS is obtained by converting an especially designed pseudopolynomial dynamic programming algorithm.