Are we predicting the actual or apparent distribution of temperate marine fishes?

Planning for resilience is the focus of many marine conservation programs and initiatives. These efforts aim to inform conservation strategies for marine regions to ensure they have inbuilt capacity to retain biological diversity and ecological function in the face of global environmental change – particularly changes in climate and resource exploitation. In the absence of direct biological and ecological information for many marine species, scientists are increasingly using spatially-explicit, predictive-modeling approaches. Through the improved access to multibeam sonar and underwater video technology these models provide spatial predictions of the most suitable regions for an organism at resolutions previously not possible. However, sensible-looking, well-performing models can provide very different predictions of distribution depending on which occurrence dataset is used. To examine this, we construct species distribution models for nine temperate marine sedentary fishes for a 25.7 km2 study region off the coast of southeastern Australia. We use generalized linear model (GLM), generalized additive model (GAM) and maximum entropy (MAXENT) to build models based on co-located occurrence datasets derived from two underwater video methods (i.e. baited and towed video) and fine-scale multibeam sonar based seafloor habitat variables. Overall, this study found that the choice of modeling approach did not considerably influence the prediction of distributions based on the same occurrence dataset. However, greater dissimilarity between model predictions was observed across the nine fish taxa when the two occurrence datasets were compared (relative to models based on the same dataset). Based on these results it is difficult to draw any general trends in regards to which video method provides more reliable occurrence datasets. Nonetheless, we suggest predictions reflecting the species apparent distribution (i.e. a combination of species distribution and the probability of detecting it). Consequently, we also encourage researchers and marine managers to carefully interpret model predictions.

The apparent paradox of colour variation in aposematic poison frogs

Toxic prey warn their predators about their unprofitability with conspicuous colour patterns that are easily learned and remembered by predators if they are uniform within a population. I studied a variable, warningly-coloured poison frog in the wild and found that such variation in colours may be related to mating advantages, parental duties, microhabitat selection and different behavioural strategies.

Controlling morphology and porosity of porous siloxane membranes through water content of precursor microemulsion

Here we report a facile method for controlling the morphology and porosity of porous siloxane membranes through manipulation of the water content of precursor microemulsions. The polymerizable microemulsion precursors consisted of a methacrylate-terminated siloxane macromonomer (MTSM) as the oil phase, nonionic surfactant (Teric G9A8), water, and cosurfactant (isopropanol). Photo-polymerization of the oil phase in the parent microemulsion solutions resulted in polymeric solids, and subsequent removal of the extractable components yielded porous PDMS membranes. The pre-cured parent microemulsion solutions and post-cured polymers were characterized by small angle X-ray scattering (SAXS) while the nanostructures of extracted porous polymer membranes were characterized by SAXS, scanning electron microscopy (SEM) and mercury porosimetry. The results indicated that nano- and micro-structures of the membranes could be modulated by the water content of the precursor microemulsions. Further, in situ photo-rheometry was used to follow the microemulsion polymerization process. The rate of polymerization and the mechanical properties of the resulting PDMS membranes also depend on the water content of precursor microemulsions. This study demonstrates a simple approach to the fabrication of a variety of novel porous PDMS membranes with controllable morphology and porosity.

Experimental verification of theoretical prediction of fiber to fiber contacts in electrospun multilayer nano-microfibrous assemblies: effect of fiber diameter and network porosity

Average number of fiber-to-fiber contacts in a fibrous structure is a prerequisite to investigate the mechanical, optical and transport properties of stochastic nanomicrofibrous networks. In this research work, based on theoretical analysis presented for the estimation of the number of contacts between fibers in electrospun random multilayer nanofibrous assembles, experimental verification for theoretical dependence of fiber diameter and network porosity on the fiber to fiber contacts has been provided. The analytical model formulated is compared with the existing theories to predict the average number of fiber contacts of nanofiber structures. The effect of fiber diameters and network porosities on average number of fiber contacts of nano-microfiber mats has been investigated. A comparison is also made between the experimental and theoretical number of inter-fiber contacts of multilayer electrospun random nanomicrofibrous networks. It has been found that both the fiber diameter and the network porosity have significant effects on the properties of fiber-to-fiber contacts.

Control of porosity and pore size of metal reinforced carbon nanotube membranes

Membranes are crucial in modern industry and both new technologies and materials need to be designed to achieve higher selectivity and performance. Exotic materials such as nanoparticles offer promising perspectives, and combining both their very high specific surface area and the possibility to incorporate them into macrostructures have already shown to substantially increase the membrane performance. In this paper we report on the fabrication and engineering of metal-reinforced carbon nanotube (CNT) Bucky-Paper (BP) composites with tuneable porosity and surface pore size. A BP is an entangled mesh non-woven like structure of nanotubes. Pure CNT BPs present both very high porosity (>90%) and specific surface area (>400 m2/g). Furthermore, their pore size is generally between 20–50 nm making them promising candidates for various membrane and separation applications. Both electro-plating and electroless plating techniques were used to plate different series of BPs and offered various degrees of success. Here we will report mainly on electroless plated gold/CNT composites. The benefit of this method resides in the versatility of the plating and the opportunity to tune both average pore size and porosity of the structure with a high degree of reproducibility. The CNT BPs were first oxidized by short UV/O3 treatment, followed by successive immersion in different plating solutions. The morphology and properties of these samples has been investigated and their performance in air permeation and gas adsorption will be reported.

The effect of microstructure on the decrease of the apparent Young's Modulus in DP 780 steel

Currently, there is a significant effort into developing novel multiphase microstructures to further improve the strength/ductility combination of advanced high-strength steels. To achieve this, the effect of the microstructure on sheet formability needs to be further understood. In this study, the effect of the microstructure on the variation of the elastic modulus in loading and unloading of DP 780 steel has been investigated. Five microstructures with varying volume fractions of ferrite and martensite were generated using different heat treatment cycles. Tension tests were performed to different strain values and the Young’s Modulus during loading and unloading was determined. The test results show that the reduction in unloading modulus with prestrain depends on the volume fraction and hardness of the martensitic phase.

Fertility and apparent genetic anticipation in Lynch syndrome

Genetic anticipation is the phenomenon in which age of onset of an inherited disorder decreases in successive generations. Inconsistent evidence suggests that this occurs in Lynch syndrome. A possible cause for apparent anticipation is fecundity bias, which occurs if the disease adversely affects fertility. The purpose of this study was to determine the effect of age of diagnosis of colorectal cancer (CRC) on lifetime fertility in Lynch syndrome, and whether this can falsely create the appearance of genetic anticipation. A computer model simulated age of diagnosis of CRC in hypothetical Lynch syndrome carriers and their offspring. The model assumed similar age distribution of CRC across generations (i.e. that there was no true anticipation). Age distribution of CRC diagnosis, and lifetime fertility rates (grouped by age of diagnosis of CRC) were determined from the Australasian Colorectal Cancer Family Registry (ACCFR). Apparent anticipation was calculated by comparing ages of diagnosis of CRC in affected parent-child pairs. A total of 1,088 patients with CRC were identified from the ACCFR. Total lifetime (cohort) fertility was related to age of diagnosis of CRC (correlation coefficient 0.13, P = 0.0001). In the simulation, apparent anticipation was 1.8 ± 0.54 years (P = 0.0044). Observed apparent anticipation in the ACCFR cohort was 4.8 ± 1.73 years (P = 0.0064). There was no difference in apparent anticipation between the simulate d and observed parent-child pairs (P = 0.89). The appearance of genetic anticipation in Lynch syndrome can be falsely created due to changes in fertility.