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The aim of this study was to quantify the efficiency of different lengths of beach seine nets for each diel period in freshwater reservoirs. Only fish older than young-of-the-year were considered. Nets of 10, 20 and 50 m length ("in-nets") were tested in an enclosed area framed by a 200 m long net (block net). The net efficiency estimate was calculated as the ratio of fish catches with the in-net and block net divided by the ratio of their respective areas. The net efficiency estimate was significantly different between day and night catches. At night, the efficiency estimate of nets depended on the size of the fish. The efficiency estimate of a 10 m long net decreased significantly in reverse correlation with fish size. A similar trend was found when using a 20 m long net. The efficiency estimate of a 50 m long net was independent of fish size. The variance in efficiency estimate between samples with a given net length was high, but decreased with longer nets. Of five species tested, only the efficiency estimate for catching bream (Abramis brama) increased significantly with the length of net. The biomass and abundance of larger fish was generally higher at night, although especially short nets exhibited a spuriously high efficiency estimate during the day, probably due to the concentrating (chasing) effect of the hauling ropes. We therefore recommend the use of a 50 m long net, since its nighttime efficiency estimate was about 0.9 in terms of both sampling abundance and biomass. A model relating the efficiency estimate and net length was developed with the data acquired. [ABSTRACT FROM AUTHOR]

The article presents a study on sediment related processes and their contribution to sediment trapping. It states that to be able to identify the said processes and quantify their relative contribution to sediment trapping, a scope of rainfall simulations was performed on a 600 meter2 hillslope consisting a pasture upslope of a 15 year old tree belt. Through the joint analysis of sediment budgets and soil surface conditions, different trapping processes has been determined. The main trapping process is the sedimentation with deposits in the backwater and as micro-terraces within the tree belt. The authors suggest that the finest fractions transported by the overland flow may be trapped through adsorption on the rich litter presented within the tree belt.

Abstract: The selectivity of a 99mm trawl codend was assessed using a codend cover fitted with a MultiSampler, which was acoustically triggered to take separate samples at three different phases of the haul. The first sample was collected during towing, the second during haul-up and the third at the surface. A total of 18 hauls were conducted with a commercial fishing vessel west of Scotland. It was demonstrated that escapes take place not only during the tow but also in the short period when the trawl is hauled back from the seabed and when the codend is at the surface. For haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus) and Norway lobster (Nephrops norvegicus), respectively, the mean percentages escaping at the surface were 16, 12 and 38% of the total escape while 17, 8 and 28% escaped during the haul-up phase. Compared to towing, the escape rate (no./min) increased for haddock by a factor 2.7 during haul-up and by a factor 1.7 at the surface, whereas the escape rates of whiting were similar for the three phases. The escape rate of Norway lobster increased by a factor of approximately 7 for both the haul-up and surface phases, compared to the towing phase. The selectivity parameters L50 (50% retention length) and SR (selection range= L75–L25) were estimated and compared for the three different phases and for the whole haul for haddock, whiting and Norway lobster. For all three species there was no significant (P >0.05) difference in L50 between the three phases of the haul. There was also no significant difference for whiting and Norway lobster when comparing the SR of the three phases, whereas the SR was significantly lower for haddock when comparing the surface phase with towing and haul-up. The estimate of L50 when towing was about 6cm lower for haddock and whiting and 9mm for Norway lobster compared to the selection curve estimated conventionally for the whole haul. Finally, the effect of sea state, duration and codend catch on the selectivity parameters were estimated for the individual phases and for the whole haul. A significant effect of at least one variable was found in all phases. [Copyright &y& Elsevier]

He, P., and Balzano, V. 2007. Reducing the catch of small shrimps in the Gulf of Maine pink shrimp fishery with a size-sorting grid device. – ICES Journal of Marine Science, 64: 1551–1557. Since implementation of the Nordmøre grid in the Gulf of Maine pink shrimp (Pandalus borealis) trawl fishery in the early 1990s, fish bycatch has been reduced drastically. However, the Nordmøre grid does not reduce the amount of small shrimps landed when the shrimps are on the fishing grounds. This paper reports on two designs of a new size-sorting grid system, one with a funnel and one without. The designs' main feature is the size-sorting grid's position, installed in front of the main Nordmøre grid. They were tested in the flume tank and at sea. Parallel tows involving two vessels and alternating tows using one vessel were made to compare the size-sorting grid system. Both size-sorting designs reduced the number of small shrimps in the catch significantly, by 38 and 45 kg−1 of catch, respectively. There was some reduction in shrimp catch rates, presumably from the release of small shrimps. There were no significant differences in the number or quantity of major bycatch species for the commercial grid and the two experimental grid designs. The designs were practical to operate and easy to install. Their application could reduce the catch of small shrimps in the pink shrimp fishery in the Gulf of Maine and in other areas. [ABSTRACT FROM PUBLISHER]

Abstract: A covered-codend experiment was done to assess the size selectivity of a codend made from 27-mm mesh hung on the bar (i.e. square mesh) for school prawns (Metapenaeus macleayi) across 10 vessels within the New South Wales (NSW) estuarine penaeid-trawl fishery. Prior to starting the experiment, a codend cover (18-mm diamond-shaped mesh) was tested and demonstrated to have no effect on the catching efficiency of a typical estuarine trawl, thereby validating its use for assessing size selectivity. There was substantial variability in the estimated carapace lengths at 50% probability of retention (L 50 ±S.E.: between 7.90±0.97 and 13.76±0.23mm) and selection ranges (SR: between 2.70±0.18 and 6.71±1.72mm) of the 27-mm square-mesh codend among trawlers and estuaries. Multi-level, generalised linear mixed-effects modelling demonstrated that this variation was explained by: (i) the catch weight of school prawns; (ii) the particular estuary being fished; and (iii) random between-tow and -trawler variability. The results are discussed in terms of the various operational, biological and environmental factors unique to each fishing operation. Despite the variability in the performance of the 27-mm square-mesh codend, an overall improvement in size selectivity compared to conventional diamond-mesh designs, combined with a high survival rate of escapees, justifies its adoption and legislation throughout the NSW estuarine penaeid-trawl fishery as a means for mitigating unwanted fishing mortalities. We also conclude that similar codends may have application in other penaeid-trawl fisheries around the world. [Copyright &y& Elsevier]

Abstract: The selection of whelk by seven experimental types of drum-net trap was evaluated in a comparative fishing study in the East Sea, Korea, between July and October 2003. The experimental traps were fished in conjunction with a control trap constructed from 20mm mesh. Three of the experimental traps used increased mesh sizes (35, 55 and 75mm), another two employed escape rings (diameters of 3 and 5cm), and the remaining two were constructed using double hoops to form gaps (widths of 2 and 4cm) around the entire circumference of the trap. The minimum legal mesh size (35mm mesh) was found to be effectively non-selective over the size range of whelk present in the fishery. The traps with 55 and 75mm mesh and the traps fitted with escape rings all had statistically significant lower estimated efficiency than the control trap. Although the double hoop traps appear to offer the greatest potential for reducing the catch of undersized whelk, these traps are the most difficult to construct, store and deploy. Further research is required to improve the selectivity of traps fitted with escape rings. [Copyright &y& Elsevier]

Abstract: Objective: To investigate the relationship between early-onset retinopathy and urinary markers of renal dysfunction. Research Design and Methods: The Diabetes Incidence Study in Sweden (DISS) aims to register all new cases of diabetes in young adults (15–34 years). In 1987–1988, 806 patients were reported and later invited to participate in a follow-up study focusing on microvascular complications after ∼10 years of diabetes. In the present study, 149 patients with type 1 diabetes, completed eye examination, and urine sampling were included. Results: The patients with retinopathy (n=58, 39%) had higher HbA1c (P<.001) and urinary IgG2/creatinine (P<.05) and IgG2/IgG4 ratios (P<.05). Patients with maculopathy had the highest levels. No significant differences in urinary albumin/creatinine, glycosaminoglycans (GAGs)/creatinine, Tamm–Horsfall protein (THP)/creatinine, and IgG4/creatinine ratios were found. Women had higher urinary albumin/creatinine (P<.01) and urinary IgG2/creatinine ratios (P<.01) than men. Conclusions: Young adults with type 1 diabetes and early-onset retinopathy had higher IgG2/creatinine and IgG2/IgG4 ratios than patients without retinopathy indicating that retinopathy is associated with a change in glomerular size selectivity. This was found in association with normal urinary albumin and THP excretion and may be suspected to reflect early general vascular changes. [Copyright &y& Elsevier]

In Tokyo Bay, conger tube-trap fishers voluntarily deployed escape holes of at least 13 mm diameter to reduce the by-catch of young conger smaller than the marketable size of 35 cm total length. Comparative fishing experiments in Tokyo Bay were carried out using tube traps with seven hole diameters (3, 9, 13.5, 14, 15, 17, and 19 mm), to obtain the size-selectivity of the escape-hole size for inshore hagfish Eptatretus burgeri and white-spotted conger Conger myriaster. On the assumption of the geometrical similarity in the combination of body g and hole perimeter m at a given retention probability, a single master curve s( R) = exp(−13.52 + 11.31 R)/(1 + exp [−13.52 + 11.31 R]) was estimated for the two species in terms of relative R = g/ m using the Share Each LEngth's Catch Total (SELECT) process based on a multinomial distribution. Almost all conger and hagfish with a girth equivalent to the hole perimeter were able to pass through the hole. Thus, the two species have a high ability to escape through a narrow space by squeezing the body through the hole in the rigid PVC tube. Optimum escape-hole size is discussed from several objectives for conger tube-trap fishery management, e.g. reduction of hagfish by-catch. This study also specifies the conditions for pooling data when fishing experiments using more than two fishing gears are replicated. [ABSTRACT FROM AUTHOR]

Abstract: Porous polymer films show interesting properties as ion selective membranes. In this work, poly(1,2-diaminobenzene) and polytyramine were deposited from hexagonal liquid crystal templates using two different surfactants. Resulting films were investigated to find evidence of mesoporous structures. While templated poly(1,2-diaminobenzene) has already been described as charge selective in the past, electrochemical experiments in this work demonstrate that another mechanism (most likely, size selectivity) also contributes to its ion selective behaviour. Films were characterised using spectroscopic ellipsometry and impedance spectroscopy. Results provide further evidence for the porosity, thinness, and the presence of ions in the templated poly(1,2-diaminobenzene) films. It is demonstrated that the use of a low-cost surfactant (Brij 56) is sufficient for the templating process. In contrast, polytyramine gave no evidence of being templated by the liquid crystal. [Copyright &y& Elsevier]

Selectivity experiments of diamond and square mesh codends with different mesh size (30, 35, 40 and 45 mm) for hairfin anchovy Setipinna taty were carried out using the covered codend method in Chinese stow net fisheries. In the present study, 5151 specimens were subsampled and asymmetric and symmetric selectivity curves (Richards and Logistic curves) were fitted to the catch data, using the maximum likelihood method according to the SELECT model. The results show that the Richards curve gives a better fit to the selectivity curve for diamond mesh codends with 30, 35 and 40-mm mesh sizes, whereas the logistic curve gives a better fit for the diamond mesh codend with 45 mm mesh size and square mesh codends with 30, 35, 40 and 45-mm mesh size. With the exception of 45-mm mesh size codends, the L50 of diamond mesh codends were insignificantly larger than those of square mesh codends. However, the selectivity curves of square mesh codends were steeper than those of diamond mesh codends, except the 30-mm mesh size codends. As for diamond mesh codends, according to the linear relationship between the L50 and mesh size, 36.5-mm mesh size codends could release 50% juvenile hairfin anchovy (below 1-year old). However, diamond mesh codends with such a mesh size are not selective for other species. [ABSTRACT FROM AUTHOR]

Abstract: Trammel net size selectivity was studied for the most important métiers in four southern European areas: the Cantabrian Sea (Atlantic, Basque Country, Spain), the Algarve (Atlantic, southern Portugal), the Gulf of Cádiz (Atlantic, Spain) and the Cyclades Islands (Mediterranean, Aegean Sea, Greece). These métiers were: cuttlefish (Sepia officinalis) and soles (Solea senegalensis, Microchirus azevia, Synaptura lusitanica) in the Algarve and the Gulf of Cádiz, sole (Solea solea) in the Cantabrian Sea and mixed fin-fish in the Cyclades. In each area, experimental trammel nets of six different types (combinations of two large outer panel mesh sizes and three small inner panel meshes) were constructed. Fishing trials were carried out on a seasonal basis (four seasons in the Cantabrian Sea, Algarve and Cyclades and two seasons in the Gulf of Cádiz) with chartered commercial fishing vessels. Overall, size selectivity was estimated for 17 out of 28 species for which sufficient data were available. Trammel nets generally caught a wide size range of the most important species, with length frequency distributions that were skewed to the right and/or bi-modal. In many cases the length frequency distributions of the different nets were highly overlapped. The Kolmogorov–Smirnov test also showed that the large outer panel meshes generally had no effect in terms of size selectivity, while the opposite was true for the small inner panel ones. Six different selectivity models (normal scale, normal location, gamma, log-normal, bi-modal and gamma semi-Wileman) were fitted to data for the most abundant species in the four areas. For fish, the bi-modal model provided the best fits for the majority of the data sets, with the uni-modal models giving poor fits in most cases. For Sepia officinalis, where trammelling or pocketing was the method of capture in 100% of the cases, the logistic model fitted by maximum likelihood was judged to be more appropriate for describing the size selective properties of the trammel nets. Our results, which are among the first ones on trammel net selectivity in European waters, will be useful for evaluating the impacts of competing gear for the socio-economically important small-scale static gear fisheries. [Copyright &y& Elsevier]

Abstract: In this contribution we address (A) size selective reactivity of anionic gold clusters relevant for catalysis and (B) femtochemistry of metallic clusters and its control by tailored laser fields. In this connection the following results will be presented. (I) General mechanism for co-adsorption of O2 and CO based on structure–reactivity relation has been obtained using DFT method which permits to elucidate fully available experimental results. (II) Simulation of pump–probe signals in the framework of negative-to-neutral-to-positive (NeNePo) spectroscopy using combination of Wigner distribution approach and MD “on the fly” allows to determine experimental conditions under which different processes such as geometric relaxation and internal vibrational relaxation (IVR) in Ag2Au can be observed. (III) We show that optimal control theory can be used as a tool for analysis of ultrafast processes on example of photoionization processes in NaK, since the shapes of the optimized pulses based on full quantum mechanical treatment can be used to deduce the mechanisms of the processes underlying the optimal control. [Copyright &y& Elsevier]

Comparative fishing trials were undertaken with two commercial collapsible pots for the crab Charybdis japonica. One pot was box-shaped with two slit entrances at the ends, while the other was dome-shaped with two open funnel entrances. Pots were placed at the bottom of a pond that is connected to Kagoshima Bay. Fishing trials were carried out using a 1-day soaking time; the bait used was mackerel. The box-shaped pot had higher catches of crabs and non-target organisms, but the number of large crabs (carapace width >8 cm) was almost half as many as that caught with the dome-shaped pot. The catch of non-target species was also greatly reduced in the dome-shaped pot, and fish caught were mostly enmeshed in the netting. The reduction in catches of small crabs and non-target organisms was due to the nature of the dome-shaped pot's larger mesh size and open entrances, which allowed for escape. The dome-shaped pot seemed more efficient for harvesting commercial size crabs, while the box-shaped pot seemed better for removing all crab sizes. [ABSTRACT FROM AUTHOR]

Slightly increased urinary albumin excretion is frequently found in patients with lymphoma and other malignancies but the pathophysiological mechanisms have yet to be clarified. In this study, parameters of renal function in lymphoma patients with microalbuminuria were evaluated. Sixty‐seven patients with histologically proven diffuse large B‐cell lymphoma were included in the study at diagnosis. Urinary albumin excretion was measured by immunoturbidimetry and microalbuminuria was defined as an excretion rate between 20 and 200 µg/min. Glomerular function was further estimated by renal clearance of creatinine and IgG, and the IgG/IgG4 charge selectivity index. Tubular function was evaluated by renal clearance of β 2 ‐microglobulin. The median value of IgG clearance was increased in the microalbuminuric patients (0.22 versus 0.18 µl/min; p = 0.03). The median selectivity index was significantly lower in patients with microalbuminuria (1.0 versus 2.2; p [ABSTRACT FROM AUTHOR]

Abstract: Gillnet catch data from the lower Yukon River, AK, collected from 1990 to 2003 in conjunction with a sonar study to estimate the abundance of migrating fish, were assembled. The full dataset contained 92,029 records with complete species and length information. A subset of data for the eight most prevalent groups of fish was selected for the estimation of net selectivity. The reduced dataset contained 89,984 records for Chinook salmon (Oncorhynchus tshawytscha), summer and fall runs of chum salmon (O. keta), coho salmon (O. kisutch), pink salmon (O. gorbuscha), humpback whitefish (Coregonus pidschian), broad whitefish (C. nasus), and various cisco (Coregonus) species. A Pearson function was used as a net selectivity model for all eight groups of fish, though a parameter was added to accommodate the catch of fish that are relatively large for a particular mesh. Because most of these relatively large fish were probably not gilled, but rather caught by body parts other than the operculum, the extra parameter can be thought of as a tangling parameter. The parameters of the modified Pearson model were estimated using maximum likelihood, and variances were estimated through bootstrapping. Gillnets were found to be most efficient, for all eight groups of fish, when fish length is approximately twice as great as the perimeter of a mesh, and the corresponding location parameter of the Pearson model was estimated with high precision. As the Pearson function has apparently not been used previously as a net selectivity model, its suitability was compared to the normal, lognormal, gamma, inverse Gaussian, and bi-normal functions, which are commonly employed as net selectivity models. Model fit was evaluated on the basis of the value of the likelihood function obtained, Akaike''s Information Criterion and scaled deviance statistics, and plots of estimated models and scaled catch data. The Pearson model was found to be quite flexible, and fit the data as well as or better than the other models for all eight groups of fish considered. Other researchers may wish to consider its use with their data. [Copyright &y& Elsevier]

• Background The plant cuticle is an extracellular lipophilic biopolymer covering leaf and fruit surfaces. Its main function is the protection of land-living plants from uncontrolled water loss. In the past, the permeability of the cuticle to water and to non-ionic lipophilic molecules (pesticides, herbicides and other xenobiotics) was studied intensively, whereas cuticular penetration of polar ionic compounds was rarely investigated.• Recent Progress Recent work measuring cuticular penetration of inorganic and organic ions is presented; the effects of molecular size of ions, temperature, wax extraction, humidity and plasticizers strongly support the conclusion that ions penetrate cuticles via water-filled pores. The cuticle covering stomata and trichomes forms the preferential site of ion penetration. This indicates that cuticles possess a pronounced lateral heterogeneity: the largest fraction of the cuticle surface is covered by the lipophilic domains of cutin and wax, but to a certain extent polar domains are also present in the cuticle, which form preferential sites of penetration for polar compounds.• The Future The chemical nature of these polar domains awaits detailed characterization, which will be of major importance in agriculture and green biotechnology, since polar paths of diffusion represent the most important transport routes for foliar-applied nutrients. Furthermore, many compounds acting as inducers of gene expression in transgenic plants are ionic and need to penetrate the cuticle via polar paths in order to be active. [ABSTRACT FROM AUTHOR]

The trophic linkage between yellow perchPerca flavescensand two exotic prey items, alewifeAlosa pseudoharengusand round gobyNeogobius melanostomus, was investigated in the extreme southern area of Lake Michigan during the summer of 2002. Yellow perch≥100 mm total length,LT( n = 1293) exhibited size selective feeding, with 148 fish containing round gobies and 120 fish containing alewives. The mean round gobyLT, preyed on by yellow perch, was 23% of the predatorLT, with a range of 7 to 47%, and mean alewifeLT was 32% of yellow perchLT, with a range of 18 to 46%. Although the selection of prey size by yellow perch increased proportionally with yellow perchLT, prey consumed appeared smaller than theoretically possible based on gape size. [ABSTRACT FROM AUTHOR]

Data from a video camera sled and research survey trawl were used to estimate size-specific trawl selectivity for Sebastolobus spp. Sizes from the camera sled video were extracted using an oblique grid plane and image analysis software. Thornyhead mean densities were 3–5 times higher with the camera sled than the survey trawl. Experimental selectivity patterns failed to conform to traditional parametric selectivity functions so a new non-parametric model was derived. The estimates of catchability for 20–25cm thornyheads were 0.25–0.75. Catchability estimates for thornyheads larger than 30cm were much lower (<0.10). A reason for low catchability at larger sizes remains unclear but may be a size-dependent interaction with the trawl, an artifact caused by low sample size of large fish in the study area, an unresolved bias in the video measurement system, or any combination of these factors. [Copyright &y& Elsevier]

The sorting grid was introduced in the Barents Sea gadoid fishery in 1997. During an experiment west of Bear Island in summer 2001, the total selectivity of a commercial cod trawl with a single grid mounted (grid selectivity×codend selectivity) was compared with that of the same trawl without a grid (codend selectivity). This is the first comparison of the selectivity of these gears during a single experiment. The results showed a surprisingly similar selection range for grid and codend selectivity: around 10 cm. With a grid mounted, the 50% retention length of the trawl rose by about 4 cm. The results demonstrate that catch rate or catch size may influence both 50% retention length and selection range. [Copyright &y& Elsevier]

We have recently demonstrated the biological synthesis of gold nanoparticles by the reduction of aqueous chloroaurate ions by the fungus Fusarium oxysporum and with extract of geranium (Pelargonium graveolens) leaf. In this paper, we demonstrate the immobilization of biogenic gold nanoparticles in lipid thin films deposited by thermal evaporation. The charge on the gold nanoparticles synthesized by both the fungus and the geranium plant extract is used to facilitate their immobilization in both anionic and cationic lipid thin films. A rough estimate of the isoelectric point of the proteins capping the gold nanoparticles synthesized using the fungus could be made by pH-dependent microgravimetry studies of the immobilization process. An interesting size and shape selectivity in the immobilized gold nanoparticles is observed in the lipid thin films. The biogenic gold nanoparticle–lipid composite films were characterized using quartz crystal microgravimetry, UV–vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy. [Copyright &y& Elsevier]

A study was undertaken on the northwestern coast of Portugal to evaluate the selectivity effect of both tooth spacing and mesh size on the catch of the white clam (Spisula solida). Two typical clam dredges, equipped with different tooth spacing and mesh size, were towed side by side. Three tooth spacing (20, 40 and 60 mm) and three mesh sizes (35, 40 and 50 mm) were investigated. The dredge selectivity experiments were performed by attaching a cover bag with a 20 mm mesh to the gear. Individual hauls were analysed by the SELECT model. The Fryer’s mixed model of between-haul variation was also applied to data. The results showed that the space between teeth does not have an effect on selectivity. Tooth length was directly related to the dredge’s capture efficiency. The only factor that contributed to dredge size selection was mesh size. The 50% retention lengths estimated for mesh sizes 30, 40 and 50 mm were 25.68, 26.35 and 31.94 mm, respectively. For all mesh sizes, very narrow selection ranges were observed. The most appropriate mesh size to be enforced within the Portuguese northwestern S. solida fishery should be 40 mm. [Copyright &y& Elsevier]

A rapid decrease of the stock of Baltic cod (Gadus morhua) has provided the incentive to improve the size selectivity in the trawl fishery. Use of escape windows is permitted in the legislation to give means of improving the size selectivity of cod as an alternative to a traditional standard codend. The history of the use of escape windows in the Baltic Sea cod fishery is reviewed. The present escape windows do not function optimally. The objective of this new experiment was to compare an improved design of escape window, which is placed in the upper panel, with that of standard codend. Three standard codends, with 105, 120 and 140 mm nominal mesh size, and three window codends, with 110, 125 and 135 mm window nominal mesh size, were tested during sea trials conducted in June and July from a commercial trawler using a twin trawl rig and the covered codend technique. A fixed and random effects model of the codend selectivity was formulated to analyse the results and determine the effects of codend type, mesh size and other recorded variables. L50 and SR increased significantly with the mesh size. L50 was significantly increased and SR significantly reduced for a window codend with the same window mesh size (WMS) as that of a standard codend. The L50 of the standard codends decreased with catch weight. An unexplained port–starboard effect was found for the window codends where the L50 depended on which of the two trawls the codend was attached to. The potential of these escape windows as a management tool to improve the size selectivity in the Baltic cod fishery is discussed. [Copyright &y& Elsevier]

The avian ectostriatum is the telencephalic recipient zone of the tectofugal pathway, which may be homologous to the colliculo-pulvinar-cortical pathway in mammals. The present paper studies the visual response properties and receptive field organization of ectostriatal cells in pigeons with extracellular recording and computer mapping techniques. The results indicate that 90% of ectostriatal cells prefer forward, downward and upward motion of visual stimuli at velocities in the range of 16–128° s–1. They respond optimally to small stimuli (1–4° visual angle), mostly preferring a target of 2°. Most cells (78.8%) have one excitatory receptive field that usually possesses one or two hotspots, some cells (13.5%) have two excitatory receptive fields each having one or two hotspots, and a few cells (7.7%) have one excitatory receptive field with an unresponsive region in the center. An inhibitory receptive field is not found surrounding the excitatory receptive field in the ectostriatal cells examined. These response properties and receptive field organization may reflect the possible roles of the ectostriatum in stimulus discrimination and visual cognition. [ABSTRACT FROM AUTHOR]

To analyze the effect of thin twine on gill net size selectivity, a series of fishing experiments using gill nets of two twine thicknesses (no. 0.8 of 0.16 mm diameter and no. 3 of 0.28 mm diameter) and three nominal mesh sizes (41 mm, 46 mm and 51 mm) was conducted in outdoor water tanks containing a rainbow trout (Oncorhynchus mykiss) population of known size frequency. For nets of the same nominal mesh size, mesh openings of the no. 0.8 twine nets were approximately 2 mm larger than those of the no. 3 twine nets. The effects of both mesh opening and twine thickness are combined in the conventional analysis with the selectivity curve against fish length. Selectivity against the ratio of fish girth to mesh perimeter was calculated to avoid the direct effect of changes in mesh openings due to twine diameter at the same nominal mesh size. Results demonstrated that the thinner twine gill net was more likely to capture rainbow trout of smaller girth than the mesh perimeter. Fish with girths smaller than the mesh perimeter were often retained by the net with its body tangled by the thinner twine, possibly due to the increased flexibility of the thinner twine. [ABSTRACT FROM AUTHOR]

SUMMARY:A series of comparative fishing experiments was carried out in waters off the east coast of Korea in 1997, using traps of six different mesh sizes (95, 112, 122, 132, 152, and 172 mm mesh opening) to determine the size selectivity of a conical trap for male red queen crab, Chionoecetes japonicus. The extended SELECT (Share Each LEngth’s Catch Total) analysis method was applied with fishing effort data to obtain trap size selectivity, with a symmetric logistic equation used to express selectivity curves. Traps of 95 mm mesh size were employed as the control gear in the analysis. Logistic and split parameters of each mesh-size trap in the SELECT model were calculated by the maximum likelihood method. The model of split parameter p fixed with equal fishing efficiency, was chosen from the likelihood ratio tests and Akaike’s Information Criterion (AIC) comparison. From the determined logistic parameters, the carapace widths of 50% retention were estimated to be 82, 85, 92, and 101 mm for 122, 132, 152, and 172 mm mesh-size traps, respectively. The selectivity curves of each mesh-size trap showed that traps of larger mesh size allowed more crabs of small carapace width and low commercial value to escape. [ABSTRACT FROM AUTHOR]

Size selectivity and catch efficiency of six diamond-mesh codends with different mesh sizes, 25–54 mm (termed as D25-D54), for conger pike (Muraenesox cinereus) were tested and compared using the covered codend method in the South China Sea (SCS). In order to address the present minimum mesh size (MMS) regulations of the trawl fishery for conger pike in the SCS, we quantified the selective properties of two legal codends, D25 and D40, which followed the MMS regulations in the studied area, and used them as baseline to compare with other codends. Our results demonstrated that the catch efficiency decreased with the increment of mesh sizes in codends. The D25 codend was insufficient to protect juvenile conger pike. For this legal codend, 54.31% of conger pike below the Market Reference Size (MRS, 22.4 cm) was retained, and more than 93% of conger pike retained would have to be discarded. Applying the other legal codend, D40, the problem of capturing juvenile fish was significantly mitigated. In this codend, only 9.61% of conger pike below the MRS was retained. However, the loss of commercial-sized fish was considerable, as about 50% fish above the MRS would escape from it. Our study will be beneficial to the enforcement and reform of the MMS regulations in China's fisheries management. [Display omitted] • Size selectivity and catch efficiency of six diamond-mesh codends for conger pike were tested and compared. • The D25 codend was insufficient to protect juvenile conger pike. • The D40 codend significantly reduced the retention of juvenile conger pike, however, lost some commercial-sized one. [ABSTRACT FROM AUTHOR]

We explored the application of two-dimensional covalent organic frameworks (2D COFs) in single molecule DNA analysis. Two ultrathin COF nanosheets were exfoliated with pore sizes of 1.1 nm (COF-1.1) and 1.3 nm (COF-1.3) and covered closely on a quartz nanopipette with an orifice of 20 ± 5 nm. COF nanopores exhibited high size selectivity for fluorescent dyes and DNA molecules. The transport of long (calf thymus DNA) and short (DNA-80) DNA molecules through the COF nanopores was studied. Because of the strong interaction between DNA bases and the organic backbones of COFs, the DNA-80 was transported through the COF-1.1 nanopore at a speed of 270 μs/base, which is the slowest speed ever observed compared with 2D inorganic nanomaterials. This study shows that the COF nanosheet can work individually as a nanopore monomer with controllable pore size like its biological counterparts.