Boat electrofishing survey of common smelt and common bullies in the Ohau Channel

We conducted a boat electrofishing survey of the Ohau Channel, which flows from Lake Rotorua to Lake Rotoiti, on 13 December 2007. The purpose of the survey was to investigate the longitudinal pattern in densities of common smelt (Retropinna retropinna) and common bullies (Gobiomorphus cotidianus) along the Ohau Channel. We caught 1,267 fish comprising three native fish species and two introduced fish species in 1.58 km of fished distance at a total of 10 sites. Native species caught were the common smelt, common bully and longfinned eel (Anguilla dieffenbachii) and introduced species were rainbow trout (Oncorhynchus mykiss) and goldfish (Carassius auratus). Assuming that the bow-mounted anodes effectively fished a 4 m swath then the total area fished was 6,328 m2 (0.632 ha). Common smelt densities varied among the 10 different sites in the Ohau Channel ranging from 0 to 10.6 fish 100 m-2. Smelt density was higher at the upstream end of the channel near the weir at the Lake Rotorua outlet, decreasing with increasing distance from the weir. Smelt were found in the littoral zones but were not caught in mid-channel habitats. In the upstream reaches of the Ohau Channel, directly below the weir, a high number of juveniles (4.4 fish 100 m-2) were captured compared to the amount of juveniles captured at the other sites (0 – 1.2 fish 100 m-2). Common bully densities varied among the 10 different sites in the Ohau Channel ranging from 0.2 to 58.3 fish 100 m-2. No longitudinal pattern in the distribution of common bullies was evident along the channel. The highest densities were found halfway along the Ohau Channel where there was an abundance of dense macrophyte beds. Common bully densities were found to be much higher in the edge habitats with macrophyte beds compared to the mid-channel habitats and the willow edge habitat where there were relatively low densities. Size frequency data shows that there is generally a higher proportion of small bullies than larger ones suggesting that recruitment is occurring. Both adult and juvenile rainbow trout were observed in the Ohau Channel. Most of these individuals were found in the upstream section of the channel below the weir and ranged from a 75 mm juvenile to a fully grown adult about 500 mm long. Large longfinned eels were also captured and were only found in the downstream section of the Ohau Channel in willow-dominated edges. In the bottom third section of the channel, near the possible artificial embayment, goldfish were present

Measuring working memory load effects on electrophysiological markers of attention orienting during a simulated drive

Intersection accidents result in a significant proportion of road fatalities, and attention allocation likely plays a role. Attention allocation may depend on (limited) working memory (WM) capacity. Driving is often combined with tasks increasing WM load, consequently impairing attention orienting. This study (n = 22) investigated WM load effects on event-related potentials (ERPs) related to attention orienting. A simulated driving environment allowed continuous lane-keeping measurement. Participants were asked to orient attention covertly towards the side indicated by an arrow, and to respond only to moving cars appearing on the attended side by pressing a button. WM load was manipulated using a concurrent memory task. ERPs showed typical attentional modulation (cue: contralateral negativity, LDAP; car: N1, P1, SN and P3) under low and high load conditions. With increased WM load, lane-keeping performance improved, while dual task performance degraded (memory task: increased error rate; orienting task: increased false alarms, smaller P3). Practitioner Summary: Intersection driver-support systems aim to improve traffic safety and flow. However, in-vehicle systems induce WM load, increasing the tendency to yield. Traffic flow reduces if drivers stop at inappropriate times, reducing the effectiveness of systems. Consequently, driver-support systems could include WM load measurement during driving in the development phase

The Effect of Pax3 Over-expression on Myoblast Function

The paired-box transcription factor 3 (Pax3), is a powerful myogenic regulatory factor during embryo-myogenesis. The expression of Pax3 is involved in determining somitic cell fate, resulting in the formation of the first differentiated muscle, the myotome. In addition, Pax3 expression in embryonic hypaxial precursor cells prevents premature differentiation, whilst promoting cellular migration and thus ensuring the proper development of limb muscles. Subsequent muscle growth in the developing embryo is provided by myogenic precursor cells marked by the expression of Pax3 and its paralogue, Pax7. Following foetal development, these precursor cells establish the distinct lineage of myogenic stem cells referred to as satellite cells, responsible for post-natal development and regeneration. However, satellite cells are not the only population of cells that generate myogenic precursor cells in adult muscle for regeneration and growth. Recently, it has been shown that in adult muscle, Pax3 is expressed in a population of novel, interstitial cells, and is up-regulated upon muscle injury. To determine the role played by Pax3 in post-natal muscle development and regeneration, three Pax3 over-expressing myoblast (C2C12) cell lines were generated and experimentally compared with control cells. Four facets of myoblast function were assessed: proliferation, differentiation, survival and migration. The proliferation assay showed that Pax3 over-expression significantly (Plt0.001) slowed C2C12 myoblast proliferation, Pax3 over-expressing clones only reached 63% of the proliferative rate of control C2C12 cells. Furthermore, this study clearly showed that over-expression of Pax3 significantly (Plt0.01) delayed the differentiation of C2C12 myoblasts. Analysis showed that following 72 h of low serum induced differentiation 52% of the control C2C12 cell population had fused to form myofibres, in comparison only 16-32% of the myoblast population that over-expressed Pax3 had fused to from myofibres. Taken together, these data suggest that following satellite cell activation, Pax3 expression could be maintained in precursor cells to expand the myogenic population, as their myogenic commitment is delayed by Pax3 expression and this would facilitate increased cell cycling, albeit at a reduced rate. Furthermore, a low percentage of fusion strongly indicates a higher proportion of cells that are renewing the quiescent satellite cell population. Furthermore, over-expression of Pax3 also conferred a dose-dependent anti-apoptotic function to C2C12 myoblasts. Myoblasts that over-expressed a low level of Pax3 were more resistant to apoptosis in comparison to control C2C12 cells and to myoblasts that over-expressed Pax3 at higher level. The anti-apoptotic function conferred by Pax3 expression would come into effect within the Pax3+ self-renewing satellite cell lineage. Finally, Pax3 over-expression was shown to increase the migratory ability of C2C12 myoblasts. In a chemotaxis assay, there was a strong indication that an intermediate over-expression of Pax3 increased myoblast sensitivity to chemotactic signals, priming cells for migration. The delay in differentiation also exhibited by Pax3 over-expression may function to allow satellite cell-derived progenitors to migrate to sites of injury, therefore enhancing skeletal muscle regenerative capacity

Evolution and comparative haemoglobin oxygen binding in new zealand mudfishes

New Zealand's five endemic mudfish (Neochanna spp.) species have distributions that differ both geographically and by habitat type. Differences in habitat preferences between species have led to the proposal of an evolutionary series within the group. A morphological cline can be observed from the galaxiform Chatham Island and Canterbury species inhabiting lakes and streams, respectively, to the anguilliform Northland and brown mudfishes of ephemeral wetlands. Morphological specializations proposed for wetland dwelling include loss of pelvic fins, reduced eyes, enlarged nostrils, development of caudal flanges, and elongation of dorsal and anal fin bases to become almost confluent with the caudal fin. Another expectation of adaptation to wetland dwelling is specializations in respiratory physiology to obtain oxygen from highly hypoxic or acidic waters, and the ability to cope with seasonal exposure to air during the drought season. Expected respiratory specializations to wetland dwelling include high oxygen affinity haemoglobins, high levels of cooperative oxygen binding, the presence of multiple haemoglobins and the ability to aestivate and survive long periods of emersion. The four mainland Neochanna species were examined to determine if differences in haemoglobin expression as well as differences in haemoglobin oxygen binding correlated with differing habitats and treatments. Whole blood oxygen affinity was determined at several pH levels (6.5, 7.0, 7.5 and 8.0) and temperatures (10'C, 15'C and 20'C), as well as different treatments (aestivating, fasting and control) using a Hemox analyzer. The presence of multiple haemoglobins was determined by isoelectric focusing. All four species displayed high oxygen affinities (p50 = 6.5 to 9.5 mm Hg at pH 7.5 15'C), moderate levels of cooperativity (Hill coefficients = 1.75 to 2.00 at pH 7.5 15'C), pH sensitivity (Bohr coefficients = -0.62 to -0.94 between pH 7.5 and 7.0 at 15'C), temperature sensitivity (ΔH = -2.20 to -15.78 k cal mol-1 between 10'C and 15'C) and the presence of multiple haemoglobins. Black, brown and Northland mudfish were able to survive aestivation for six weeks but there were no changes between air-breathing and water-breathing individuals with respect to oxygen binding characteristics. Although there is evidence of habitat specialization in haemoglobin physiology between mudfish species, differences between species did not correlate with the evolutionary series proposed for specialization to dwelling in ephemeral wetlands and latitudinal distributions of mudfish species appear to strongly dictate oxygen binding properties of mudfish whole blood

Inhibitory Control and Peer Passengers Predict Risky Driving in Young Novice Drivers - A Simulator Study

This driving simulator study aimed to investigate (1) effects of peer passengers on a variety of risky driving measures, and (2) moderating effects of inhibitory control on these peer passenger effects. Two age groups (n = 30, 17-18 year-olds; n = 20, 21-24 year-olds) participated. Each participant completed two 28km test-drives in a medium-fidelity driving simulator. In the first drive, participants were asked to drive as they normally do. In the second drive, participants again were asked to drive as they normally do, now in the presence of a peer passenger. Measures of risky driving were: standard deviation of lateral lane position (SDLP), collisions with road hazards, speeding, and red light running. The results showed: (1) that peer presence can have negative (‘risk increasing’) but also positive (‘protective’) effects on driving performance, depending on the specific driving measure: whereas red light running increased, the number of collisions and SDLP decreased with peer passengers; (2) a moderating effect of inhibitory control on the peer passenger effect of speeding as (a) in a sub-group with low inhibitory control an increase in speeding occurred with peers, while (b) in a sub-group with high inhibitory control there was no effect of peers on speeding. This suggests that those with higher inhibitory control are more successful in resisting peer pressure

Training Working Memory of Older Drivers: The Effect on Working Memory and Simulated Driving Performance

This study aimed to investigate in older drivers whether a working memory (WM) training would enhance WM, and whether improvement of WM transfers to enhanced driving ability. 54 older drivers participated in the study, but due to drop-out, 38 participants (mean age 70.34) remained in the sample. Participants were randomly assigned to a control (N=19) or an experimental condition (N=19). Each participant conducted a WM training during 25 days. During the pre-test and post-test, WM and driving ability were assessed. Results indicate that the training lead to an improvement of WM. In addition, there was an improvement of several driving measures, that was however independent of the level of WM improvement. These findings will be discussed

Exploring the Driving Behavior of Youth with an Autism Spectrum Disorder: A Driver Instructor Questionnaire

Youth with an autism spectrum disorder (ASD) depend to a great extent on friends and family for their transportation needs. Although little research exists, Cox et al. (2012) surveyed parents/caregivers of youth with ASD (previously) attempting to learn to drive. This study serves as an extension by surveying driver instructors. Several questions queried advice for teaching youth with ASD how to drive, and for improving the current driving education to better fit the needs of youth with ASD. Furthermore, respondents were asked to indicate whether specific characteristics, often associated with ASD, have an impact on driving ability. A total of 52 driver instructors reported potential problems when teaching youth with ASD to drive. Advice for teaching youth with ASD to drive mainly focused on a need for structure, clarity, visual demonstration, practice, repetition and an individualized approach. Results however also showed that the relation between ASD and driving performance might not always be negative but can be positive. Practical implications are provided

Dynamic travel information strategies in advance traveler information systems and their effect on route choices along highways

Advance Traveler Information Systems (ATIS) inform drivers about traffic incidences and expected travel times/ delays en-route. An online computer study was conducted in Qatar to investigate drivers' willingness to divert to an alternative route given changes in expected travel conditions. Respondents’ route choices were queried after exposure for 6 seconds to varying display strategies. The results from a binary logistic regression and a stated preference survey showed that delay times and displayed colors on a Graphical Route Information Panel (GRIP) effectively influence drivers to take the alternative route, while total travel times were preferred for Variable Message Signs (VMS)

A new method for improved standardisation in three-dimensional computed tomography cephalometry

Interest for three-dimensional computed tomography cephalometry has risen over the last two decades. Current methods commonly rely on the examiner to manually point-pick the landmarks and/or orientate the skull. In this study, a new approach is presented, in which landmarks are calculated after selection of the landmark region on a triangular model and in which the skull is automatically orientated in a standardised way. Two examiners each performed five analyses on three skull models. Landmark reproducibility was tested by calculating the standard deviation for each observer and the difference between the mean values of both observers. The variation can be limited to 0.1 mm for most landmarks. However, some landmarks perform less well and require further investigation. With the proposed reference system, a symmetrical orientation of the skulls is obtained. The presented methods contribute to standardisation in cephalometry and could therefore allow improved comparison of patient data