Imperfect sensitivity, or imperfect detection, is a feature of all survey methods that needs to be accounted for when interpreting survey results. Detection of environmental DNA (eDNA) is ...increasingly being used to infer species distributions, yet the sensitivity of the technique has not been fully evaluated. Sensitivity, or the probability of detecting target DNA given it is present at a site, will depend on both the survey method and the concentration and dispersion of target DNA molecules at a site. We present a model to estimate target DNA concentration and dispersion at survey sites and to estimate the sensitivity of an eDNA survey method. We fitted this model to data from a species‐specific eDNA survey for Oriental weatherloach, Misgurnus anguillicaudatus, at three sites sampled in both autumn and spring. The concentration of target DNA molecules was similar at all three sites in autumn but much higher at two sites in spring. Our analysis showed the survey method had ≥95% sensitivity at sites where target DNA concentrations were ≥11 molecules per litre. We show how these data can be used to compare sampling schemes that differ in the number of field samples collected per site and number of PCR replicates per sample to achieve ≥95% sensitivity at a given target DNA concentration. These models allow researchers to quantify the sensitivity of eDNA survey methods to optimize the probability of detecting target species, and to compare DNA concentrations spatially and temporarily.
Summary
Determining the timing and location of reproductive events is critical for efficient management of species. However, methods currently used for aquatic species are costly, time intensive, ...biased and often require destructive or injurious sampling. Hence, developing a non‐invasive sampling method to accurately determine the timing and location of reproduction for aquatic species would be extremely valuable.
We conducted an experimental and field study to determine the influence of spawning, and the mass release of spermatozoa in particular, on environmental DNA (eDNA) concentrations. Using a quantitative PCR approach we monitored changes in nuclear and mitochondrial eDNA concentrations over time.
The data from the experimental study and the field survey supported our hypothesis that spawning events are characterized by higher concentrations of nuclear relative to mitochondrial eDNA. Outside of the reproductive period, we find that nuclear and mitochondrial DNA fragments are equally abundant in environmental water samples.
We have shown that changes in the relative abundance of nuclear and mitochondrial eDNA can be used to monitor spawning activity of the endangered Macquarie perch. Our method is likely to be transferrable to other aquatic species and can be particularly useful to increase our understanding of the spawning biology of cryptic, rare or threatened species as well as design and evaluate environmental management actions and determine species establishment.
Nitric oxide (NO) has been implicated as part of the ripening regulatory network in fleshy fruits. However, very little is known about the simultaneous action of NO on the network of regulatory ...events and metabolic reactions behind ripening-related changes in fruit color, taste, aroma and nutritional value. Here, we performed an in-depth characterization of the concomitant changes in tomato (Solanum lycopersicum) fruit transcriptome and metabolome associated with the delayed-ripening phenotype caused by NO supplementation at the pre-climacteric stage. Approximately one-third of the fruit transcriptome was altered in response to NO, including a multilevel down-regulation of ripening regulatory genes, which in turn restricted the production and tissue sensitivity to ethylene. NO also repressed hydrogen peroxide-scavenging enzymes, intensifying nitro-oxidative stress and S-nitrosation and nitration events throughout ripening. Carotenoid, tocopherol, flavonoid and ascorbate biosynthesis were differentially affected by NO, resulting in overaccumulation of ascorbate (25%) and flavonoids (60%), and impaired lycopene production. In contrast, the biosynthesis of compounds related to tomato taste (sugars, organic acids, amino acids) and aroma (volatiles) was slightly affected by NO. Our findings indicate that NO triggers extensive transcriptional and metabolic rewiring at the early ripening stage, modifying tomato antioxidant composition with minimal impact on fruit taste and aroma.
Environmental DNA (eDNA) metabarcoding surveys enable rapid, noninvasive identification of taxa from trace samples with wide‐ranging applications from characterizing local biodiversity to identifying ...food‐web interactions. However, the technique is prone to error from two major sources: (a) contamination through foreign DNA entering the workflow, and (b) misidentification of DNA within the workflow. Both types of error have the potential to obscure true taxon presence or to increase taxonomic richness by incorrectly identifying taxa as present at sample sites, but multiple error sources can remain unaccounted for in metabarcoding studies. Here, we use data from an eDNA metabarcoding study designed to detect vertebrate species at waterholes in Australia's arid zone to illustrate where and how in the workflow errors can arise, and how to mitigate those errors. We detected the DNA of 36 taxa spanning 34 families, 19 orders and five vertebrate classes in water samples from waterholes, demonstrating the potential for eDNA metabarcoding surveys to provide rapid, noninvasive detection in remote locations, and to widely sample taxonomic diversity from aquatic through to terrestrial taxa. However, we initially identified 152 taxa in the samples, meaning there were many false positive detections. We identified the sources of these errors, allowing us to design a stepwise process to detect and remove error, and provide a template to minimize similar errors that are likely to arise in other metabarcoding studies. Our findings suggest eDNA metabarcoding surveys need to be carefully conducted and screened for errors to ensure their accuracy.
Eradications of invasive species are usually expensive and difficult to conduct. Knowing when to declare an eradication successful requires distinguishing between failed detection of the target ...species due to imperfect sensitivity of the detection method and true species absence. This is difficult because the sensitivities of many detection methods are unknown.
Environmental DNA (eDNA) methods can be used to detect species by analysing DNA present in environmental samples. eDNA has been promoted as a particularly sensitive and cost‐effective way to detect species at low densities and, importantly, the sensitivity of eDNA surveys can be quantified. Nevertheless, the effort and costs involved in detecting species at extremely low densities, such as required during eradication, have not been previously calculated.
We evaluated the sensitivity of eDNA surveys in detecting the invasive European carp, Cyprinus carpio, in two lakes in Tasmania, Australia, one in which carp have been eradicated and a second in which carp are currently being eradicated. We determined the sampling effort and associated cost required to detect the species at very low density in these lakes.
While our eDNA survey detected the current low density carp population present in Lake Sorell, we show that an exponential increase in sampling effort and associated cost will be required to confidently detect the species as the population declines. Similarly, while our eDNA survey corroborated the species absence from Lake Crescent, our detection confidence was low. We quantify the survey effort and financial investment required to confidently establish eradication success in Lake Crescent.
Synthesis and applications. Estimating the environmental DNA (eDNA) survey effort and cost required to detect species at a given density will enable practitioners to make informed decisions on the feasibility of implementing such surveys. Quantifying the sensitivity of eDNA surveys will also inform the confidence practitioners should place in eDNA detection results to ensure appropriate management actions are implemented and provide a suitable stopping point at which to confidently declare eradication success.
Estimating the environmental DNA (eDNA) survey effort and cost required to detect species at a given density will enable practitioners to make informed decisions on the feasibility of implementing such surveys. Quantifying the sensitivity of eDNA surveys will also inform the confidence practitioners should place in the results of eDNA detection surveys to ensure appropriate management actions are implemented and provide a suitable stopping point at which to confidently declare eradication success.
We establish the large scale convergence of a class of stochastic weakly nonlinear reaction–diffusion models on a three dimensional periodic domain to the dynamic
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3
4
model within the framework of ...paracontrolled distributions. Our work extends previous results of Hairer and Xu to nonlinearities with a finite amount of smoothness (in particular
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9
is enough). We use the Malliavin calculus to perform a partial chaos expansion of the stochastic terms and control their
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p
norms in terms of the graphs of the standard
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3
4
stochastic terms.
Summary
The tongue plays an important role in oral functions. Reduced tongue strength is often noted among children with mouth‐breathing behaviour. The purposes of this study were to measure the ...tongue pressure in children with mouth‐breathing behaviour, to compare these values to those of children with nasal‐breathing behaviour and to analyse the relationship between age and tongue pressure in children with a mouth‐breathing pattern and in children with a nasal‐breathing pattern. In this cross‐sectional analytical observational study, we enroled 40 children aged 5‐12 years who either exhibited mouth‐breathing behaviour (n = 20) or nasal‐breathing behaviour (gender‐ and age‐matched ±2 years controls; n = 20). Tongue pressure was evaluated using the Iowa Oral Performance Instrument; 3 measurements were recorded for each participant, with a 30‐seconds rest interval. The average tongue pressure in the mouth‐breathing group was lower than that in the nasal‐breathing group. There was no difference in tongue pressure between genders. There was a strong and direct correlation between tongue pressure and age in the nasal‐breathing group. The breathing pattern impacts tongue pressure development.
Despite the prevalence of stress in everyday life and its impact on happiness, health, and cognition, little is known about the neural substrate of the experience of everyday stress in humans. We use ...a quantitative and noninvasive neuroimaging technique, arterial spin-labeling perfusion MRI, to measure cerebral blood flow (CBF) changes associated with mild to moderate stress induced by a mental arithmetic task with performance monitoring. Elicitation of stress was verified by self-report of stress and emotional state and measures of heart rate and salivary-cortisol level. The change in CBF induced by the stress task was positively correlated with subjective stress rating in the ventral right pref rontal cortex (RPFC) and left insula/putamen area. The ventral RPFC along with right insula/putamen and anterior cingulate showed sustained activation after task completion in subjects reporting a high stress level during arithmetic tasks. Additionally, variations of baseline CBF in the ventral RPFC and right orbitofrontal cortex were found to correlate with changes in salivary-cortisol level and heart rate caused by undergoing stress tasks. We further demonstrated that the observed right prefrontal activation could not be attributed to increased cognitive demand accompanying stress tasks and extended beyond neural pathways associated with negative emotions. Our results provide neuroimaging evidence that psychological stress induces negative emotion and vigilance and that the ventral RPFC plays a key role in the central stress response.
Global motion perception entails the ability to extract the central direction tendency from an extended area of visual space containing widely disparate local directions. A substantial body of ...evidence suggests that local motion signals generated in primary visual cortex (V1) are spatially integrated to provide perception of global motion, beginning in the middle temporal area (MT) in macaques and its counterpart in humans, hMT. However, V2 and V3 also contain motion-sensitive neurons that have larger receptive fields than those found in V1, giving the potential for spatial integration of motion signals. Despite this, V2 and V3 have been overlooked as sites of global motion processing. To test, free of local-global confounds, whether human V2 and V3 are important for encoding global motion, we developed a visual stimulus that yields a global direction yet includes all possible local directions and is perfectly balanced at the local motion level. We then attempted to decode global motion direction in such stimuli with multivariate pattern classification of fMRI data. We found strong sensitivity to global motion in hMT, as expected, and also in several higher visual areas known to encode optic flow. Crucially, we found that global motion direction could be decoded in human V2 and, particularly, in V3. The results suggest the surprising conclusion that global motion processing is a key function of cortical visual areas V2 and V3. A possible purpose is to provide global motion signals to V6.
Humans can readily detect the overall direction of movement in a flock of birds despite large differences in the directions of individual birds at a given moment. This ability to combine disparate motion signals across space underlies many aspects of visual motion perception and has therefore received considerable research attention. The received wisdom is that spatial integration of motion signals occurs in the cortical motion complex MT+ in both human and nonhuman primates. We show here that areas V2 and V3 in humans are also able to perform this function. We suggest that different cortical areas integrate motion signals in different ways for different purposes.
Background
Alteration in tongue mobility requires rehabilitation work through oral motor exercises. These exercises can be integrated with computer games to increase the patient’s motivation during ...treatment.
Objective
To investigate the influence of tongue mobility on children’s motor performance in a computer game reliant on lingual movements.
Methods
A cross‐sectional descriptive observational study was carried out with 16 children with altered tongue mobility and 16 children with normal tongue mobility. The subjects were between 8 and 12 years of age. They underwent a clinical evaluation of the tongue and performed an activity using an intra‐oral joystick controlled by the tongue to play a simple computer game. The game consisted of targets appearing on the screen that the participants had to reach by moving the joystick control rod. Afterward, the participants answered a feedback questionnaire. Motor performance in the game, measured by the number of reached targets and by the time to reach the targets, was compared between groups and across directions of tongue movement and order of appearance of the targets.
Results
The group with altered tongue mobility presented a higher time to reach the target in the downward direction and in the first and last 12 targets and a lower number of targets reached in the left direction, upward direction, and in the first 12 targets than the control group. The direction of the movement influenced tongue performance in both groups.
Conclusion
Children with altered tongue mobility exhibited a worse performance than those with normal tongue mobility.
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