A framework for testing and comparing binaural models

Auditory research has a rich history of combining experimental evidence with computational simulations of auditory processing in order to deepen our theoretical understanding of how sound is processed in the ears and in the brain. Despite significant progress in the amount of detail and breadth covered by auditory models, for many components of the auditory pathway there are still different model approaches that are often not equivalent but rather in conflict with each other. Similarly, some experimental studies yield conflicting results which has led to controversies. This can be best resolved by a systematic comparison of multiple experimental data sets and model approaches. Binaural processing is a prominent example of how the development of quantitative theories can advance our understanding of the phenomena, but there remain several unresolved questions for which competing model approaches exist. This article discusses a number of current unresolved or disputed issues in binaural modelling, as well as some of the significant challenges in comparing binaural models with each other and with the experimental data. We introduce an auditory model framework, which we believe can become a useful infrastructure for resolving some of the current controversies. It operates models over the same paradigms that are used experimentally. The core of the proposed framework is an interface that connects three components irrespective of their underlying programming language: The experiment software, an auditory pathway model, and task-dependent decision stages called artificial observers that provide the same output format as the test subject

Using fine-scale catch predictions to examine spatial variation in growth and catchability of Panulirus cygnus along the west coast of Australia

Puerulus settlement has been monitored throughout the western rock lobster Panulirus cygnus fishery for nearly 40 years. These data, in combination with indices of effort and water temperature, were used to produce recruitment-catch relationships for each 1° transect of latitude in the coastal part of this fishery from Kalbarri to Cape Leeuwin, as well as at the offshore Abrolhos Islands (total of eight transects). The fine spatial scales of these models provided estimates of certain life history traits that are known to affect lobster catches between adjacent fishing ports. This catch modelling showed that the proportions of 3- and 4-year-old post-settlement lobsters contributing to the catches varied markedly from the southern to northern transects, suggesting that juvenile lobsters grow substantially faster in the warmer northern and offshore waters of this fishery. These proportions provide accurate estimates of juvenile growth rates, which are vital in the construction of location-specific growth algorithms required by the age-structured models used in the management of this fishery.Model estimates of density-dependent mortality were greater in the more densely populated centre of the fishery and markedly lower at the northern and southern limits of this species distribution. Annual increases in fishing efficiency were also found to be lowest at the northern and southern extremes of the fishery and greatest in the centre of the fishery, where technology advances and increased fleet mobility have enabled the fleet to increase efficiency by 1–3% each year. Catchability (q) was found to be most influenced by water temperatures in the cooler southern transects, whereas at the Abrolhos Islands, changes in water temperature produced almost no discernible change in q. The catch modelling was also used to quantify the impact of management changes introduced in the 1993/94 fishing season. Increased protection of female lobsters and an 18% pot reduction resulted in a 3–4% permanent reduction in the catch rates of lobsters throughout most of the coastal fishery, whereas at the offshore Abrolhos Islands, catch rates increased by c. 20%, presumably owing to a reduction in the level of pot saturation

Effects of starvation on survival, biomass, and lipid composition of newly hatched larvae of the blue swimmer crab, Portunus pelagicus (Linnaeus, 1758)

Lipids are crucial nutrients for survival and development of crustacean larvae. This study investigated the effects of starvation on survival, body weight, and lipid composition of newly hatched larvae of Portunus pelagicus. The results showed that during starvation, average survival time of newly hatched zoea I larvae was 3.87 days. A significant decreasing trend was detected for individual dry weight (DW) during starvation and was described as DW = 0.2x2 − 1.462x + 15.023, R2 = 0.9985, where x is the starvation duration in days. DW and total lipids decreased by 17.42 and 38.46 % after 3 days of starvation, respectively. For newly hatched larvae, total lipids were dominated by phospholipids (PL) (75.55–93.57 %) and 50.39 % of PL were utilized during the 3-day starvation period. This indicates that membrane structural lipids of newly hatched P. pelagicus larvae were oxidized as an energy source during continuous starvation. There were concurrent increases in free fatty acids and cholesterol that probably resulted from the decomposition of sterol esters to free fatty acids and cholesterol. Newly hatched P. pelagicus larvae contained substantially higher levels of 20:5n3 (18.90 %) and 22:6n3 (18.24 %) than other Portunid crabs. During starvation, the highest fatty acid reduction rates were found for 20:4n6, 20:5n3, and 22:6n3 (P < 0.05), and the preferential depletion of these fatty acids may suggest that the HUFA requirements of early P. pelagicus larvae are lower than those of the other Portunids