Search

This study investigated the relative performance of two computer input devices appropriate for persons sharing similar motor challenges: a head operated device and expanded membrane cursor keys. Performance was evaluated in the context of a Fitts' law target acquisition task. For this initial phase of investigation, subjects without disabilities were selected to focus on performance differences inherent in the devices and their operation. Results indicated that the total time to acquire a target was significantly faster for the head device than for the expanded cursor keys. For typical young adults, the head-operated device required less time to reach asymptote performance by simplifying the cognitive demands for device operation. These results suggest that for persons unable to isolate their fingers, head-operated controls may offer advantages over input devices operated by the upper extremities. [ABSTRACT FROM AUTHOR]

Coral reefs are biodiverse ecosystems that rely on trophodynamic transfers from primary producers to consumers through the detrital pathway. The sponge loop hypothesis proposes that sponges consume dissolved organic carbon (DOC) and produce large quantities of detritus on coral reefs, with this turn-over approaching the daily gross primary production of the reef ecosystem. In this study, we collected samples of detritus in the epilithic algal matrix (EAM) and samples from potential sources of detritus over two seasons from the forereef at Carrie Bow Cay, Belize. We chose this location to maximize the likelihood of finding support for the sponge loop hypothesis because Caribbean reefs have higher sponge abundances than other tropical reefs worldwide and the Mesoamerican barrier reef is an archetypal coral reef ecosystem. We used stable isotope analyses and eDNA metabarcoding to determine the composition of the detritus. We determined that the EAM detritus was derived from a variety of benthic and pelagic sources, with primary producers (micro- and macroalgae) as major contributors and metazoans (Arthropoda, Porifera, Cnidaria, Mollusca) as minor contributors. None of the sponge species that reportedly produce detritus were present in EAM detritus. The cnidarian signature in EAM detritus was dominated by octocorals, with a scarcity of hard corals. The composition of detritus also varied seasonally. The negligible contribution of sponges to reef detritus contrasts with the detrital pathway originally proposed in the sponge loop hypothesis. The findings indicate a mix of pelagic and benthic sources in the calmer summer and primarily benthic sources in the more turbulent spring., Competing Interests: Beverly McClenaghan, Lesley Berghuis, Nicole Fahner and Hoda Rajabi are employees of eDNAtec Inc. Mehrdad Hajibabaei is the founder and Chief Scientific Officer of eDNAtec Inc., (©2024 Olinger et al.)

Environmental DNA (eDNA)-based methods of species detection are enabling various applications in ecology and conservation including large-scale biomonitoring efforts. qPCR is widely used as the standard approach for species-specific detection, often targeting a fish species of interest from aquatic eDNA. However, DNA metabarcoding has the potential to displace qPCR in certain eDNA applications. In this study, we compare the sensitivity of the latest Illumina NovaSeq 6000 NGS platform to qPCR TaqMan assays by measuring limits of detection and by analysing eDNA from water samples collected from Churchill River and Lake Melville, NL, Canada. Species-specific, targeted next generation sequencing (NGS) assays had significantly higher sensitivity than qPCR, with limits of detection 14- to 29-fold lower. For example, when analysing eDNA, qPCR detected Gadus ogac (Greenland cod) in 21% of samples, but targeted NGS detected this species in 29% of samples. General NGS assays were as sensitive as qPCR, while simultaneously detecting 15 fish species from eDNA samples. With over 34,000 fish species on the planet, parallel and sensitive methods such as NGS will be required to support effective biomonitoring at both regional and global scales., (© 2022 The Authors. Molecular Ecology Resources published by John Wiley & Sons Ltd.)

The deep ocean is the largest biome on Earth and faces increasing anthropogenic pressures from climate change and commercial fisheries. Our ability to sustainably manage this expansive habitat is impeded by our poor understanding of its inhabitants and by the difficulties in surveying and monitoring these areas. Environmental DNA (eDNA) metabarcoding has great potential to improve our understanding of this region and to facilitate monitoring across a broad range of taxa. Here, we evaluate two eDNA sampling protocols and seven primer sets for elucidating fish diversity from deep sea water samples. We found that deep sea water samples (> 1400 m depth) had significantly lower DNA concentrations than surface or mid-depth samples necessitating a refined protocol with a larger sampling volume. We recovered significantly more DNA in large volume water samples (1.5 L) filtered at sea compared to small volume samples (250 mL) held for lab filtration. Furthermore, the number of unique sequences (exact sequence variants; ESVs) recovered per sample was higher in large volume samples. Since the number of ESVs recovered from large volume samples was less variable and consistently high, we recommend the larger volumes when sampling water from the deep ocean. We also identified three primer sets which detected the most fish taxa but recommend using multiple markers due the variability in detection probabilities and taxonomic resolution among fishes for each primer set. Overall, fish diversity results obtained from metabarcoding were comparable to conventional survey methods. While eDNA sampling and processing need be optimized for this unique environment, the results of this study demonstrate that eDNA metabarcoding can facilitate biodiversity surveys in the deep ocean, require less dedicated survey effort per unit identification, and are capable of simultaneously providing valuable information on other taxonomic groups., Competing Interests: B.M., N.F., H.R. A.M. and G.S. are employees of eDNAtec Inc. M.H. is the founder and Chief Scientific Officer. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Using molecular genetic information to guide population management can improve the sustainability of species in captivity. However, empirical population genetics has not been commonly applied to species management programs in zoos. One limitation may be the availability of genetic resources (e.g., markers, primers, etc.) for species held in zoos. To assess the extent to which species held in zoos have been studied using population genetics in the wild, we conducted a systematic literature review of close to 8,000 papers. We synthesized information on the availability and scale of population genetics studies across amphibian, bird, mammal, and reptile species held in zoos, and discussed their potential for informing ex situ management. We found that more than half of the species in zoos (52%) already have some genetic markers described in the literature specific for them, or a congeneric species, that could be further developed to aid the management of zoo populations, and the accumulation of these resources has been steady over the past decades. Furthermore, the proportion of species with genetic resources is even higher (62%) for species that are being managed through a formal breeding program in zoos. Our study provides encouraging results for captive program managers interested in integrating population genetics into ex situ management strategies., (© 2020 Wiley Periodicals, Inc.)

Environmental DNA (eDNA) metabarcoding is an increasingly popular method for rapid biodiversity assessment. As with any ecological survey, false negatives can arise during sampling and, if unaccounted for, lead to biased results and potentially misdiagnosed environmental assessments. We developed a multi-scale, multi-species occupancy model for the analysis of community biodiversity data resulting from eDNA metabarcoding; this model accounts for imperfect detection and additional sources of environmental and experimental variation. We present methods for model assessment and model comparison and demonstrate how these tools improve the inferential power of eDNA metabarcoding data using a case study in a coastal, marine environment. Using occupancy models to account for factors often overlooked in the analysis of eDNA metabarcoding data will dramatically improve ecological inference, sampling design, and methodologies, empowering practitioners with an approach to wield the high-resolution biodiversity data of next-generation sequencing platforms., Competing Interests: B.M. and Z.G.C. are employees of eDNAtec Inc. and M.H. is the founder and Chief Scientific Officer of eDNAtec Inc. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Species of grasshopper have been divided into three diet classifications based on mandible morphology: forbivorous (specialist on forbs), graminivorous (specialist on grasses), and mixed feeding (broad-scale generalists). For example, Melanoplus bivittatus and Dissosteira carolina are presumed to be broad-scale generalists, Chortophaga viridifasciata is a specialist on grasses, and Melanoplus femurrubrum is a specialist on forbs. These classifications, however, have not been verified in the wild. Multiple specimens of these four species were collected, and diet analysis was performed using DNA metabarcoding of the gut contents. The rbcLa gene region was amplified and sequenced using Illumina MiSeq sequencing. Levins' measure and the Shannon-Wiener measure of niche breadth were calculated using family-level identifications and Morisita's measure of niche overlap was calculated using operational taxonomic units (OTUs). Gut contents confirm both D. carolina and M. bivittatus as generalists and C. viridifasciata as a specialist on grasses. For M. femurrubrum, a high niche breadth was observed and species of grasses were identified in the gut as well as forbs. Niche overlap values did not follow predicted patterns, however, the low values suggest low competition between these species.

Background: Despite the established benefits of exercise for adults with arthritis, participation is low. Safe, evidence-based, self-directed programs, which have the potential for high reach at a low cost, are needed., Purpose: To test a 12-week, self-directed, multicomponent exercise program for adults with arthritis., Design: Randomized controlled trial. Data were collected from 2010 to 2012. Data were analyzed in 2013 and 2014., Setting/participants: Adults with arthritis (N=401, aged 56.3 [10.7] years, 85.8% women, 63.8% white, 35.2% African American, BMI of 33.0 [8.2]) completed measures at a university research center and participated in a self-directed exercise intervention (First Step to Active Health(®)) or nutrition control program (Steps to Healthy Eating)., Intervention: Intervention participants received a self-directed multicomponent exercise program and returned self-monitoring logs for 12 weeks., Main Outcome Measures: Self-reported physical activity, functional performance measures, and disease-specific outcomes (arthritis symptoms and self-efficacy) assessed at baseline, 12 weeks, and 9 months., Results: Participants in the exercise condition showed greater increases in physical activity than those in the nutrition control group (p=0.01). Significant improvements, irrespective of condition, were seen in lower body strength, functional exercise capacity, lower body flexibility, pain, fatigue, stiffness, and arthritis management self-efficacy (p values<0.0001). More adverse events occurred in the exercise than nutrition control condition, but only one was severe and most were expected with increased physical activity., Conclusions: The exercise program improves physical activity, and both programs improve functional and psychosocial outcomes. Potential reasons for improvements in the nutrition control condition are discussed. These interventions have the potential for large-scale dissemination. This study is registered at Clinicaltrials.gov NCT01172327., (Copyright © 2015 American Journal of Preventive Medicine. All rights reserved.)

Children and adults with disabilities frequently rely on computers to complete written tasks. Those with significant motor limitations typically use alternative computer-input devices since the traditional keyboard and mouse are insufficient to accommodate their abilities. For persons unable to isolate their fingers, input devices controlled by movements of the head or whole hand or arm movements may be among the options considered. This study investigated the performance of a head-operated device and expanded membrane cursor keys for text entry. Data from 24 young adults indicated the head-operated device performed significantly faster given reduced cognitive demands for device operation, increased stimulus-response compatibility, and simplicity of movement. Use of the expanded membrane cursor keys resulted in significantly lower error rates. No significant differences in comfort or ease of use were reported for the two devices. The relative performance of device options for users sharing similar motor challenges provides rehabilitation specialists with important clinical information.

Objective: To examine differences in gait and postural stability of obese and nonobese prepubertal boys., Design: Percentage of gait cycle in double support was examined to determine significant differences. Postural stability was compared using temporal and frequency measures of the center of pressure in static stance., Setting: Gait was examined using videography on a 30-meter walkway. Postural stability was examined using a measurement platform., Participants: Ten obese (>95th percentile in body mass index) and 10 nonobese (15th to 90th percentile in body mass index) prepubertal boys aged 8 to 10yrs., Intervention: Participants were examined at three walking cadences as determined by preferred gait cadence. Full vision, darkness, and visually confused conditions were used to accentuate static postural stability differences., Main Outcome Measures: In the presence of dynamic stability differences (gait), static stability measures further investigated stability differences., Results: Obese boys spent significantly (p < .02) greater percentage of gait cycle in dual stance. Obese boys showed significantly (p < .01) greater sway areas, energy, and variability primarily in the medial/lateral direction., Conclusions: Dual stance differences suggest diminished dynamic stability in obese boys. Greater sway areas in medial/lateral direction in obese boys and the absence of significant frequency measures suggest that the instability observed in obese boys is caused by excess weight rather than underlying postural instability.

Objective: To examine the feasibility of using spectral analysis techniques to identify potential biomarkers of diminished postural control in elderly individuals., Design: Data from spectral signatures (derived from postural sway) of 21 young adults and 42 elderly individuals classified as "high" or "low" risk with regard to functional balance capacity were analyzed using Risk Category (3) x Sensory Condition (3) multivariate analyses of variance. Postural control was challenged by varying the visual conditions under which individuals stood on a measurement platform., Results: Results indicated that measures of central tendency and dispersion of the spectral frequency distribution from medial-lateral components of sway (but not antero-posterior sway) clearly differentiated between "high" and "low" risk elderly. Low risk elderly were not different from young adults. High risk elderly exhibited greater dispersion and lower mean frequency than other groups., Conclusions: Differences in spectral characteristics of medial-lateral components of sway were more related to risk category than to age. Elderly persons with high functional balance capacity displayed characteristics similar to those of young adults. Thus, spectral frequency analysis techniques may be a clinically useful tool for identifying individuals potentially at risk of falling.

The purpose of this study was to design and evaluate the validity of an automated technique to assess body density using a computerized hydrostatic weighing system. An existing hydrostatic tank was modified and interfaced with a microcomputer equipped with an analog-to-digital converter. Software was designed to input variables, control the collection of data, calculate selected measurements, and provide a summary of the results of each session. Validity of the data obtained utilizing the automated hydrostatic weighing system was estimated by: evaluating the reliability of the transducer/computer interface to measure objects of known underwater weight; comparing the data against a criterion measure; and determining inter-session subject reliability. Values obtained from the automated system were found to be highly correlated with known underwater weights (r = 0.99, SEE = 0.0060 kg). Data concurrently obtained utilizing the automated system and a manual chart recorder were also found to be highly correlated (r = 0.99, SEE = 0.0606 kg). Inter-session subject reliability was determined utilizing data collected on subjects (N = 16) tested on two occasions approximately 24 h apart. Correlations revealed high relationships between measures of underwater weight (r = 0.99, SEE = 0.1399 kg) and body density (r = 0.98, SEE = 0.00244 g X cm-1). Results indicate that a computerized hydrostatic weighing system is a valid and reliable method for determining underwater weight.

Researchers of the future will depend upon computer technology to address questions that previously could not be answered using traditional methods of data acquisition. Recent advances in computer design and software availability have eliminated many of the limitations previously associated with computer use in the laboratory setting. Although computerisation facilitates the acquisition of laboratory data, identification of errors introduced into the measurement is often more difficult. The laboratory computer is only one component of an automated data acquisition system. A system designed to collect physiological data comprises several primary components, including: (a) sensing element; (b) signal amplification/conditioning circuits; (c) analogue display; (d) computer interface; (e) laboratory computer; and (f) acquisition software. The acquisition and conditioning of analogue signals is accomplished using traditional laboratory procedures familiar to the researcher. Converting this analogue signal into a digital format used by the computer, however, represents new techniques. Fundamentals of computerised data acquisition are discussed. An understanding of how an automated data acquisition system is configured and the techniques used to transform the values will assist the user in identifying sources of error introduced into the measurement. Additionally, familiarization with the methods of computerisation will provide insight into future applications of computer technology in the human performance laboratory.

Research in motor control indicates that there are fixed patterns of activity which occur in certain muscle groups involved in standing in adults. The purpose of this study was to assess patterns of duration of muscle activity during quiet standing with and without superimposed arm movement in young children with normal and delayed motor development. Thirty-three children 4, 6, 8 and 10 years of age were screened for level of motor development and classified as either normally or slowly developing. Children performed two tasks: standing and standing with a superimposed 90 degree shoulder abduction movement. Using surface electrodes, EMG activity was monitored in Gastrocnemius, Tibialis Anterior and Erector Spinae muscle groups. The percentage of time activity was present in individual muscle groups was analyzed as a function of age and developmental level. Results indicated that quiet standing in children with delayed motor development was characterized by greater duration of activity in trunk than in leg muscles while in normal children, there was a more equal distribution of muscle activity between the legs and trunk. Both groups of children accommodated superimposed arm movement by increasing the percentage of time Erector Spinae activity was present. Patterns of duration of muscle activity in the legs were, however, different for the two groups of children.

The purpose of this study was to design, construct, and validate an alternative subject/instrument interface to collect metabolic data for individuals who, because of impairment, are unable to use a mouthpiece. An industrial designer directed the development of an interface design which would facilitate subject acceptance. A total of 13 subjects (eight children with cerebral palsy and five nonneurologically impaired) participated in the validation study. Metabolic data were collected at rest and during three levels of exercise, using both the traditional mouthpiece and the interface designed for this study. Exercise intensities were matched for both experimental conditions. Subjects exercised using an electrically braked ergometer configured for arm pedaling. A modification in a Beckman Metabolic Cart allowed for the collection of values with a standard mouthpiece and low-flow interface. Validity of the interface was evaluated using a concurrent, criterion procedure. Correlations of mouthpiece vs interface data during rest and across each exercise level for oxygen consumption were high (r = 0.94 to 0.84; p less than 0.05). Similar results were obtained for carbon dioxide production (r = 0.92 to 0.85; p less than 0.05).