Significant Effect Of Position Research Articles

P 200. Coupling of the sensorimotor cortical activation explored by blood-oxygenation-level-dependent signal navigated and traditional magnetic evoked potential recordings

Introduction The blood-oxygenation-level-dependent (BOLD) signal in functional magnetic resonance imaging (fMRI) reflects associated hemodynamics for a specific motor task. Motor evoked potentials (MEPs) represent the excitability of the motor cortex. Recently the MEP recording can be visually guided by the BOLD signal in fMRI. However, the two methods may represent diverse physiological mechanisms ( Krivanekova et al., 2012 , Antal et al., 2011 ). Objectives To study the coupling of the sensorimotor cortical activation observed in fMRI BOLD signals and measured by traditional MEP recordings. Materials and methods Ten healthy, right-handed subjects (7 men, mean age: 34.6 ± 7.6 years) participated in this study. Functional imaging was acquired by using a 3.0T GE MR scanner with a single-shot EPI sequence. The subjects were requested to perform simple, repetitive abduction movement at right index finger while they saw a go-signal appeared on the projection screen and to take a rest during no-go signal periods. Transcranial magnetic stimulation (TMS) was delivered through a focal figure-of-eight stimulating coil. The coil was held tangential to the scalp with the handle pointing backwards and ∼45° away from the midline. Twenty single TMS trials were measured with a randomly varying intertrial interval ranging from 7.5 to 12.5 s at four coil positions. The electrophysiological optimal (EO) position was determined as the site where TMS at a slightly suprathreshold intensity produced consistently the largest MEPs in right first dorsal interosseus (FDI). The site was marked on the scalp to assure a constant placement of the coil throughout this session. The other three positions were determined by a frameless MR-navigation system (Visor™). The maximal BOLD signals at left primary motor cortex (BM1), left primary sensory cortex (BS1) and the lateral margin of the BOLD activity (BL) were targeted by the guidance of the navigation system. Two TMS intensities which were adjusted to produce MEPs of about 0.5 mV (low intensity) and 1 mV (high intensity) in peak-to-peak amplitude in the right FDI muscle were tested. In total 8 recording sessions including 4 positions and 2 intensities were completed by a randomized order for each subject. The mean MEP amplitude of each session was analyzed by a two-way repeated measures analysis of variance (rmANOVA) with the within-subject factors of POSITION and INTENSITY. Results All subjects demonstrated a clear BOLD signal in the left sensorimotor cortex with response to the right finger movement. RmANOVA of the MEP amplitudes revealed significant main effects of POSITION and INTENSITY, and a significant interaction between POSITION and INTENSITY. The post hoc analysis revealed a significant MEP difference between the four positions except EO-BM1 and BS1-BL at high intensity stimulation (all p Conclusion Findings suggest that the coupling of the BOLD signals and the MEPs can be TMS-intensity dependent. A distinct localization of the BOLD signal in M1 or S1 by the TMS-navigation system may significantly vary the MEP findings under a high TMS-intensity condition.

Ultrasound does not provide reliable results for the measurement of the patellar tendon cross sectional area

PurposeThis study examined the reliability of patellar tendon cross sectional area (CSA) measurement using brightness mode ultrasonography. MethodsThe patellar tendon CSA of fourteen participants was examined on two different days and at three different positions (proximal, median and distal). Five trials per day were conducted in each position, replacing the ultrasound probe on every trial. The images were examined by three different and equally experienced observers. We compared the mean of the five trials in each position to examine the day, observer and position effect. Further, Bland and Altman plots, root mean square (RMS) differences and intraclass correlation coefficients (ICC) were calculated. ResultsThere was a significant (p<0.05) day, observer and position effect on the CSA, while the average ICC was 0.592. The Bland and Altman plots showed that differences between conditions or groups, should be in average lower than 37% or higher than 55% of the patellar tendon CSA to be important for clinical or intervention studies. ConclusionOur findings show low reliability of the method, which resulted from the low clarity and unclear visibility of tissue boundaries in the ultrasound images. Therefore, the measurement of the CSA of the patellar tendon using ultrasound does not provide accurate and reliable results.

Auditory, Visual, and Bimodal Data Link Displays and How They Support Pilot Performance

The design of data link messaging systems to ensure optimal pilot performance requires empirical guidance. The current study examined the effects of display format (auditory, visual, or bimodal) and visual display position (adjacent to instrument panel or mounted on console) on pilot performance. Subjects performed five 20-min simulated single-pilot flights. During each flight, subjects received messages from a simulated air traffic controller. Messages were delivered visually, auditorily, or bimodally. Subjects were asked to read back each message aloud and then perform the instructed maneuver. Visual and bimodal displays engendered lower subjective workload and better altitude tracking than auditory displays. Readback times were shorter with the two unimodal visual formats than with any of the other three formats. Advantages for the unimodal visual format ranged in size from 2.8 s to 3.8 s relative to the bimodal upper left and auditory formats, respectively. Auditory displays allowed slightly more head-up time (3 to 3.5 seconds per minute) than either visual or bimodal displays. Position of the visual display had only modest effects on any measure. Combined with the results from previous studies by Helleberg and Wickens and Lancaster and Casali the current data favor visual and bimodal displays over auditory displays; unimodal auditory displays were favored by only one measure, head-up time, and only very modestly. Data evinced no statistically significant effects of visual display position on performance, suggesting that, contrary to expectations, the placement of a visual data link display may be of relatively little consequence to performance.

Viscoplastic Model with Zero-Thickness Interface Elements for Lateral Earth Pressure on Wall Due to Line Load

This work presents a viscoplastic model for predicting earth pressure distribution generated behind an instrumented wall due to line loads in addition to backfill. Eight-nodded two-dimensional quadrilateral elements are adopted for idealization of wall and soil, whereas, the interface between them is idealized by six-nodded zero thickness interface elements. The nonlinear behavior of soil is modeled as viscoplastic or time-dependent with Mohr–Coulomb criterion, while the wall is modeled as elastic material. The solution employed is based on 2 × 2 Gauss integration rule and incremental procedure with iterations using the explicit time-marching scheme. The results indicate significant effects of initial stresses, interface roughness, and both position and magnitude of line loads on lateral earth pressure distribution along the wall, in addition to, the applicability of the model and the efficiency of the computer program developed.

Transcranial Doppler sonography as a potential screening tool for preanaesthetic evaluation

Intraoperative cervical spine rotation may compromise cerebral blood flow in susceptible individuals by distortion of cervical arteries. To investigate the effect of five cervical spine positions on cerebral blood flow in the middle cerebral artery. Prospective observational study. University hospital. Fifty-six male and 24 female patients scheduled for general anaesthesia for routine surgery. Exclusion criteria were cranial spine pathology and cerebral vascular disease. Maximum rotation of the head to the left and right side with and without hyperextension, and hyperextension in the neutral position. Change of mean blood flow velocity in the middle cerebral artery measured by transcranial Doppler sonography. Age had a significant effect on mean blood flow velocity in the left middle cerebral artery in the neutral position (P = 0.047). There was a significant difference in mean blood flow velocity in the left middle cerebral artery between patients younger than 40 years and patients older than 59 years [61.2 (16.6) ml min(-1) vs. 47.7 (16.2) ml min(-1); P = 0.015]. There was a significant effect of head position on mean blood flow velocity in both the left and in the right middle cerebral arteries (P = 0.039 left, P = 0.025 right). Twenty patients had a decrease of more than 20% from their baseline mean blood flow velocity. Neck rotation and/or extension resulted in a significant change of blood flow in the middle cerebral artery.

운동 자세에 따른 몸통 들기 운동 시 가슴과 허리 폄 근육의 근활성도 비교

The purpose of this study was to compare the muscle activities of the thoracic extensor(TE) and lumbar extensor(LE) during trunk lift (TL) exercise according to exercise position. Seventeen healthy subjects with no medial history of back pain were recruited for this study. Subjects performed the TL exercise in prone, quadruped and heel-sitting positions. The activities of the TE and LE were measured using surface electromyography during TL exercise in each exercise position. A one-way repeated-measures analysis of variance (ANOVA) was used to compare the normalized muscle activities of the TE and LE and the TE/LE ratio. The results showed that there was not significant effect of exercise position on the muscle activities of TE(p>.05). However, there was significant effect of exercise position on the muscle activities of LE and the TE/LE ratio(p>.05). Post hoc pair-wise comparisons with Bonferroni correction showed that both muscle activities of LE and TE/LE ratio in prone position were significantly different in those in heel-sitting and quadruped positions, during TL exercise, respectively. The TE/LE ratio was the greatest for TL exercise in heel-sitting position. Therefore, for selective activation of the TE muscle, we recommend performing the TL exercise in heel-sitting or quadruped position.

Cyclic performance of beam–column joints with extended column fixed at base. Part I: experimental investigation

The seismic performance of a non-seismically detailed reinforced concrete (RC) beam–column joint with column pinned and fixed at the base is experimentally investigated in this paper. Six half-scale RC beam–column specimens were tested to study the effect of inflection point on the cyclic behaviour of beam–column sub-assemblages. The specimens were separated into two groups. The shape of specimens in the first group was cruciform; the size of the column in those specimens was varied while the size of beam was kept nearly constant. The dimensions and reinforcing detail of specimens in the second group were identical to those in the first one except that the column was extended to the footing and fixed at the base. The main variable in this study was the relative stiffness between beam and column, which affects the position of the inflection point. The test results demonstrated a significant effect of inflection point position on the load capacity, joint shear stress and failure mode.

Are cannabis prevalence estimates comparable across countries and regions? A cross-cultural validation using search engine query data

BackgroundPrevalence estimation of cannabis use is usually based on self-report data. Although there is evidence on the reliability of this data source, its cross-cultural validity is still a major concern. External objective criteria are needed for this purpose. In this study, cannabis-related search engine query data are used as an external criterion. MethodsData on cannabis use were taken from the 2007 European School Survey Project on Alcohol and Other Drugs (ESPAD). Provincial data came from three Italian nation-wide studies using the same methodology (2006–2008; ESPAD-Italia). Information on cannabis-related search engine query data was based on Google search volume indices (GSI). (1) Reliability analysis was conducted for GSI. (2) Latent measurement models of “true” cannabis prevalence were tested using perceived availability, web-based cannabis searches and self-reported prevalence as indicators. (3) Structure models were set up to test the influences of response tendencies and geographical position (latitude, longitude). In order to test the stability of the models, analyses were conducted on country level (Europe, US) and on provincial level in Italy. ResultsCannabis-related GSI were found to be highly reliable and constant over time. The overall measurement model was highly significant in both data sets. On country level, no significant effects of response bias indicators and geographical position on perceived availability, web-based cannabis searches and self-reported prevalence were found. On provincial level, latitude had a significant positive effect on availability indicating that perceived availability of cannabis in northern Italy was higher than expected from the other indicators. ConclusionAlthough GSI showed weaker associations with cannabis use than perceived availability, the findings underline the external validity and usefulness of search engine query data as external criteria. The findings suggest an acceptable relative comparability of national (provincial) prevalence estimates of cannabis use that are based on a common survey methodology. Search engine query data are a too weak indicator to base prevalence estimations on this source only, but in combination with other sources (waste water analysis, sales of cigarette paper) they may provide satisfactory estimates.

Effect of visual displays and locations on laparoscopic surgical training task

The number of minimally invasive surgical (MIS) procedures has substantially increased since its introduction due to health and recovery benefits for patients. However, there are potential performance issues in MIS for surgeons due to perceptual processing demands associated with supporting technologies. Monitor location has been identified as a major factor influencing performance in these types of procedures. This study examined the effect of multiple monitors on performance during a laparoscopic surgical training task (peg transfer among instruments). Twenty-four novice subjects were exposed to different monitor conditions including a default position, a biomechanically compatible position, and a position collocated with the operating surface as well as the combination of the latter two. Subjective rankings and cognitive workload were also assessed. Results revealed a significant effect of monitor position on task time when compared to subjects’ baseline training task time using the default monitor setup. Collocating the monitor with the operating surface was shown to be superior in terms of task time. There were no significant differences among monitor positions in terms of perceived workload. The results of this study provide an applicable guide for the design of MIS setups in the operating room to promote surgeon performance.

Anatomical distribution of the degree of mineralization of bone tissue in human femoral neck: Impact on biomechanical properties

Osteoporotic hip fractures represent a major public health problem associated with high human and economic costs. The anatomical variation of the tissue mineral density (TMD) and of the elastic constants in femoral neck cortical bone specimens is an important determinant of bone fragility. The purpose of this study was to show that a Synchrotron radiation microcomputed tomography system coupled with a multiscale biomechanical model allows the determination of the 3-D anatomical dependence of TMD and of the elastic constants (i.e. the mechanical properties of an anisotropic material) in human femoral neck.Bone specimens from the inferior femoral neck were obtained from 18 patients undergoing standard hemiarthroplasty. The specimens were imaged using 3-D synchrotron micro-computed tomography with a voxel size of 10.13μm, leading to the determination of the anatomical distributions of porosity and TMD. The elastic properties of bone tissue were computed using a multiscale model. The model uses the experimental data obtained at the scale of several micrometers to estimate the components of the elastic tensor of bone at the scale of the organ.Statistical analysis (ANOVA) revealed a significant effect of the radial position on porosity and TMD and a significant effect of axial position on TMD only. Porosity was found to increase in the radial direction moving from the periosteum inwards (p<10−5). At any given distance from the periosteum, porosity does not vary noticeably along the bone axis. TMD was found to be significantly higher (p<10−5) in the periosteal region than in other bone locations and decreases from the periosteal to the endosteal region with an average slope of 10.05g.cm−3.m−1, the decrease being faster in the porous part of the samples (average slope equal of 30.04g.cm−3.m−1) than in dense cortical bone. TMD was found to decrease from the distal to the proximal part of the femur neck (average slope of 6.5g.cm−3.m−1). Considering TMD variations in the radial direction induces weak changes of bone properties compared to constant TMD. TMD variations in the axial direction are responsible for a significant variation of elastic constants.These results demonstrate that the anatomical variations of TMD affect the bone elastic properties, which could be explained by the complex stress field in bone affecting bone remodeling. TMD spatial variations should be taken into account to properly describe the spatial heterogeneity of elastic coefficients of bone tissue at the organ scale.

Pollen:ovule ratio and its relationship with other floral traits in Papilionoideae (Leguminosae): an evaluation with Argentine species

The pollen:ovule ratio (P/O) has traditionally been used as a rough estimator of plant breeding systems. It has been shown that plant breeding systems are associated with particular floral traits. In this study, we determined the P/O in 21 Leguminosae species from Argentina and explored relationships between P/O and taxonomic position, flower size, floral rewards, pollen presentation and pollination mechanisms. According to the results, 15 out of the 21 species classified were obligate xenogamous, although some of them have been recorded as facultative xenogamous in previous studies. There was a significant effect of taxonomic position (genus), reward type and pollination mechanism on P/O. Species offering only nectar as a floral reward (which were species with a brush mechanism) had a significantly lower P/O than species offering pollen or pollen and nectar. Species with the brush pollination mechanism had the lowest P/O, while species with valvular and pump mechanism had the highest P/O. However, pollen presentation (primary and secondary) and flower size did not have a significant effect on P/O. Our results demonstrate that P/O variability is determined by taxonomic position and pollination mechanism in this plant group.

Restoring longleaf pine ( Pinus palustris Mill.) in loblolly pine ( Pinus taeda L.) stands: Effects of restoration treatments on natural loblolly pine regeneration

Historical land use and management practices in the southeastern United States have resulted in the dominance of loblolly pine ( Pinus taeda L.) on many upland sites that historically were occupied by longleaf pine ( Pinus palustris Mill.). There is currently much interest in restoring high quality longleaf pine habitats to such areas, but managers may also desire the retention of some existing canopy trees to meet current conservation objectives. However, fast-growing natural loblolly pine regeneration may threaten the success of artificially regenerated longleaf pine seedlings. We evaluated the establishment and growth of natural loblolly pine regeneration following different levels of timber harvest using single-tree selection (Control (uncut, residual basal area ∼16 m 2/ha), MedBA (residual basal area of ∼9 m 2/ha), LowBA (residual basal area of ∼6 m 2/ha), and Clearcut (complete canopy removal)) and to different positions within canopy gaps (approximately 2800 m 2) created by patch cutting at two ecologically distinct sites within the longleaf pine range: Fort Benning, GA in the Middle Coastal Plain and Camp Lejeune, NC in the Lower Coastal Plain. The density of loblolly pine seedlings was much higher at Camp Lejeune than at Fort Benning at the end of the first growing season after harvesting. Following two growing seasons, there were no significant effects of canopy density or gap position on the density of loblolly pine seedlings at either site, but loblolly pine seedlings were taller on treatments with greater canopy removal. Prescribed fires applied following the second growing season killed 70.6% of loblolly pine seedlings at Fort Benning and 64.3% of seedlings at Camp Lejeune. Loblolly pine seedlings were generally less than 2 m tall, and completeness of the prescribed burns appeared more important for determining seedling survival than seedling size. Silvicultural treatments that include canopy removal, such as patch cutting or clearcuts, will increase loblolly pine seedling growth and shorten the window of opportunity for control with prescribed fire. Therefore, application of prescribed fire every 2–3 years will be critical for control of loblolly pine regeneration during restoration of longleaf pine in existing loblolly pine stands.

The effect of feed trough position on choice of defecation area in farrowing pens by loose sows

The primary aim of the present study was to investigate how the feed trough position affects the sow's choice of defecation area in a loose house farrowing pen. The eliminative behaviour of 24 1st parity sows was studied in a cross-over design. The feed trough and the water were positioned either in the activity area towards the neighbouring pen or in the activity area towards the aisle. On day 15 after farrowing, the feed trough and the water were moved to the opposite position. Videotapes were observed continuously on real time and the time of urination or defecation were recorded along with head and hindquarter positions in the period of days 7–14 and in the period of days 21–28 after farrowing. The feed trough position had a significant effect ( P < 0.001) on sow head position when eliminating. Sows preferred the head to be located as far away from the resting area and the feed trough as possible when eliminating. For the hindquarter position, there was a significant effect ( P < 0.001) of feed trough position on the number of observations that the hindquarter was over the slatted area when eliminating. A confounding effect could be that the sow's hindquarter position was influenced by a partition wall placed in one end of the pen. No significant difference was found between observations periods on frequency of urination or defecation. The results demonstrate the importance of design of farrowing pens for loose housed sows to ensure that the sow eliminate in the designated areas.

The role of grammatical category information in spoken word retrieval.

We investigated the role of lexical syntactic information such as grammatical gender and category in spoken word retrieval processes by using a blocking paradigm in picture and written word naming experiments. In Experiments 1, 3, and 4, we found that the naming of target words (nouns) from pictures or written words was faster when these target words were named within a list where only words from the same grammatical category had to be produced (homogeneous category list: all nouns) than when they had to be produced within a list comprising also words from another grammatical category (heterogeneous category list: nouns and verbs). On the other hand, we detected no significant facilitation effect when the target words had to be named within a homogeneous gender list (all masculine nouns) compared to a heterogeneous gender list (both masculine and feminine nouns). In Experiment 2, using the same blocking paradigm by manipulating the semantic category of the items, we found that naming latencies were significantly slower in the semantic category homogeneous in comparison with the semantic category heterogeneous condition. Thus semantic category homogeneity caused an interference, not a facilitation effect like grammatical category homogeneity. Finally, in Experiment 5, nouns in the heterogeneous category condition had to be named just after a verb (category-switching position) or a noun (same-category position). We found a facilitation effect of category homogeneity but no significant effect of position, which showed that the effect of category homogeneity found in Experiments 1, 3, and 4 was not due to a cost of switching between grammatical categories in the heterogeneous grammatical category list. These findings supported the hypothesis that grammatical category information impacts word retrieval processes in speech production, even when words are to be produced in isolation. They are discussed within the context of extant theories of lexical production.

Visual working memory for motion sequences

Event Abstract Back to Event Visual working memory for motion sequences Nahidsadat Zokaei1*, Nikos Gorgoraptis1, 2, Bahador Bahrami1, 3, Paul Bays1, 2 and Masud Husain1, 2 1 Institute of Cognitive Neuroscience (UCL), United Kingdom 2 Institute of Neurology (UCL), United Kingdom 3 Institute of Anthropology, Archaeology Linguistics Aarhus University, Denmark The cognitive mechanisms of visual working memory for sequentially presented objects are not fully understood. We investigated the precision of memory for motion direction of sequentially presented colored objects. Observers viewed random dot motion stimuli displayed sequentially at fixation. At the end of each sequence, participants were asked to adjust a colored probe’s direction to match the direction of motion of the stimulus with the same color. We quantified precision as the reciprocal of the standard deviation of error in response direction. The results show a decrease in precision for motion directions presented within longer sequences. There was a significant effect of serial position of target within each sequence; last item was remembered best. Recency effect was influenced by the number of preceding items; precision of memory for the last item was lower when presented in longer sequences. We applied a probabilistic model of performance to integrate possible sources of error in memory. The model takes into account possible changes in variability in memory for target direction as well as the probability of responding to a non-target direction and at random. The fall in precision for last item presented in longer sequences was explained by an increase in variability in memory for target direction. A similar decrease in precision within longer sequences was observed in other serial positions of the target. This was explained by an increase in probability of responding to a non-target motion direction. These results are compatible with a dynamic resource model of memory whereby a limited resource is shared between items presented in a sequence. The amount of memory allocated to each item is affected by the preceding items and the items that follow it. Keywords: cognitive control, working memory Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Poster Presentation Topic: Poster Sessions: Performance Monitoring and Cognitive Control Citation: Zokaei N, Gorgoraptis N, Bahrami B, Bays P and Husain M (2011). Visual working memory for motion sequences. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00277 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 21 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Dr. Nahidsadat Zokaei, Institute of Cognitive Neuroscience (UCL), London, United Kingdom, nahid.zokaei@psy.ox.ac.uk Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Nahidsadat Zokaei Nikos Gorgoraptis Bahador Bahrami Paul Bays Masud Husain Google Nahidsadat Zokaei Nikos Gorgoraptis Bahador Bahrami Paul Bays Masud Husain Google Scholar Nahidsadat Zokaei Nikos Gorgoraptis Bahador Bahrami Paul Bays Masud Husain PubMed Nahidsadat Zokaei Nikos Gorgoraptis Bahador Bahrami Paul Bays Masud Husain Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Comparison of Muscle-Activation Patterns During the Conventional Push-Up and Perfect· Pushup™ Exercises

Manufacturers of Perfect·Pushup™ handgrips claim enhanced muscular recruitment when compared with the conventional hand-on-floor push-up exercise. Electromyographic (EMG) data were recorded using surface electrodes from the right-sided triceps brachii, pectoralis major, serratus anterior (SA), and posterior deltoid muscles during push-ups performed from 3 different hand positions: (a) shoulder width, (b) wide base, and (c) narrow base (NB). Push-ups were performed under 2 conditions: (a) standard push-up and (b) Perfect·Pushup™ handgrips. We recruited 20 healthy subjects, 11 men (24.9 ± 2.6 years) and 9 women (23.8 ± 1 years). Subjects completed 3 consecutive push-ups for each hand position under both conditions. Push-up speed was controlled using a metronome, and testing order was randomized. We recorded peak EMG activity for each muscle during each of the push-ups and normalized EMG values by maximum muscle contractions (% maximum voluntary isometric contraction [MVIC]). Electromyographic data were analyzed with 3 (hand position) × 2 (condition) repeated-measures analysis of variance with a post hoc Bonferroni-adjusted simple effects test to detect significant position effects for position by condition interactions (α = 0.05). A push-up required considerable muscle activation of the triceps brachii (73-109% MVIC), pectoralis major (95-105% MVIC), SA (67-87% MVIC), and posterior deltoid (11-21% MVIC) whether performed using the conventional hand-on-floor position or the Perfect·Pushup™ handgrips. The NB hand position was most effective for preferentially activating the triceps brachii and posterior deltoid muscles. Based upon EMG activation from 4 muscles, the Perfect·Pushup™ handgrips do not appear to preferentially enhance muscular recruitment when compared with the conventional push-up method.

Effects of nozzle type and spray angle on spray deposition in ivy pot plants

Fewer plant protection products are now authorised for use in ornamental growings. Frequent spraying with the same product or a suboptimal technique can lead to resistance in pests and diseases. Better application techniques could improve the sustainable use of the plant protection products still available. Spray boom systems--instead of the still predominantly used spray guns--might improve crop protection management in greenhouses considerably. The effect of nozzle type, spray pressure and spray angle on spray deposition and coverage in ivy pot plants was studied, with a focus on crop penetration and spraying the bottom side of the leaves in this dense crop. The experiments showed a significant and important effect of collector position on deposition and coverage in the plant. Although spray deposition and coverage on the bottom side of the leaves are generally low, they could be improved 3.0-4.9-fold using the appropriate application technique. When using a spray boom in a dense crop, the nozzle choice, spray pressure and spray angle should be well considered. The hollow-cone, the air-inclusion flat-fan and the standard flat-fan nozzle with an inclined spray angle performed best because of the effect of swirling droplets, droplets with a high momentum and droplet direction respectively.

Variability in isotope discrimination factors in coral reef fishes: implications for diet and food web reconstruction.

Interpretation of stable isotope ratios of carbon and nitrogen (δ13C and δ15N) is generally based on the assumption that with each trophic level there is a constant enrichment in the heavier isotope, leading to diet-tissue discrimination factors of 3.4‰ for 15N (ΔN) and ∼0.5‰ for 13C (ΔC). Diet-tissue discrimination factors determined from paired tissue and gut samples taken from 152 individuals from 26 fish species at Ningaloo Reef, Western Australia demonstrate a large amount of variability around constant values. While caution is necessary in using gut contents to represent diet due to the potential for high temporal variability, there were significant effects of trophic position and season that may also lead to variability in ΔN under natural conditions. Nitrogen enrichment increased significantly at higher trophic levels (higher tissue δ15N), with significantly higher ΔN in carnivorous species. Changes in diet led to significant changes in ΔN, but not tissue δ15N, between seasons for several species: Acanthurus triostegus, Chromis viridis, Parupeneus signatus and Pomacentrus moluccensis. These results confirm that the use of meta-analysis averages for ΔN is likely to be inappropriate for accurately determining diets and trophic relationships using tissue stable isotope ratios. Where feasible, discrimination factors should be directly quantified for each species and trophic link in question, acknowledging the potential for significant variation away from meta-analysis averages and, perhaps, controlled laboratory diets and conditions.

014 How do musculoskeletal pain, avoidant coping and sickness absence relate to each other?

BackgroundMusculoskeletal pain is common and causes extensive sickness absence and work disability in many industrialised countries. The prevalence of musculoskeletal morbidity increases by decreasing socio-economic position and it appears that...

Distribution of ground-dwelling beetle assemblages (Coleoptera) across ecotones between natural oak forests and mature pine plantations in North China

This paper studied edge effects resulting from logging to reforestation on the distribution of ground-dwelling beetles (Coleoptera) across ecotones between natural oak forests and mature pine plantations established after harvesting of natural forests. Using pitfall traps, ground-dwelling beetles were investigated at three replicated plots (ecotones) with three sampling positions of slope (lower, middle and upper) for each plot. Rarefaction estimates of species richness indicated that traps on natural forests and transition zones had more species than mature plantations did, and traps on the middle slope had more species than on the lower and upper slopes did. Results of an ANOVA analysis, which used forest type and slope position as factors and number of species and individuals as the response variables, showed a significant effect of forest type and slope position, and a significant interaction between forest type and slope position. Multivariate analyses (DCA and CCA) showed that beetles of transition zones were more similar to those of natural forests than to those of mature plantations, and that some environmental characteristics, i.e., proportion of broad-leaved trees, canopy cover and elevation (slope position), significantly affected species abundances. We conclude that the logging of natural oak forests and the reforestation of pine plantations can result in subtle variation in the composition and distribution of beetle assemblages at a local scale and such variation should be taken into account when conservation issues are involved.