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Freshwater fishes exhibit a wide range of auditory adaptations and capabilities, which are assumed to help them navigate their environment, avoid predators, and find potential mates. Yet, we know very little about how freshwater environments sound to fish, or how fish with different auditory adaptations respond to different soundscapes. We first compiled data on fish hearing acuity and adaptations and provided a portrait of how anthropogenic sounds compare to natural sounds in different freshwater soundscapes. We then conducted a sound‐enrichment field experiment at Lake Saint Pierre, a large fluvial lake in Canada, to evaluate the effect of motorboat sound exposure on the fish community by looking at the extent to which changes in species abundances were linked to auditory adaptations. Data compilation showed that the hearing acuity of most species overlaps with a wide range of ambient and anthropogenic underwater sounds while the field experiment showed that species with more specialized auditory structures were captured less often in sound‐enriched traps, indicating avoidance behavior. Our findings highlight the importance of considering species' sensorial adaptations when evaluating the community‐scale effects of anthropogenic sounds on the fish community, especially at low levels of anthropogenic activity. [ABSTRACT FROM AUTHOR]

We assume HT ht to be a diagonal matrix, such that HT ht , and that HT ht , HT ht , and HT ht are mutually and internally independent. [Extracted from the article]

In isotopic studies of mobile consumers, measurement error in spatial location is almost inevitable when individuals are observed only once. This error can have considerable impacts on the interpretation of ecologically important features, such as individual movement behaviour and dietary niche breadth. This study introduces a measurement error modelling framework for estimating movement scale and isotopic fractionation for consumers that move and feed along a linear isoscape gradient.The model assumes that the key mechanism underlying the difference in spatial isotopic regression slopes of mobile consumers and their baseline resources is the presence of measurement error in the spatial location of consumers. Measurement error is assumed to arise from consumer movements, which are represented by realistic movement kernels. Simulations with known parameter values are used to evaluate the performance of the models under scenarios involving different combinations of consumer mobility and sample size. Several variants of the model are fit to empirical data, and their parameter estimates are compared with those of alternative models.In simulations with known parameter values, model estimates of movement scale converged to the known values and had substantially smaller bias and variance than those of alternative models. Estimates of movement scale and fractionation for empirical data were consistent with previously reported estimates.Neglecting measurement error in spatial location is likely to hinder progress in spatial isotopic analyses. The proposed framework provides a statistically principled basis for incorporating measurement error in spatial location into isoscape analyses to provide improved estimates of parameters of interest, such as movement scale and fractionation. The framework is sufficiently general to be applicable to a variety of species, isotopic tracers, environments and spatial scales. Logical next steps to extend the framework could involve modelling of multiple species, nonlinear isoscape gradients and 2‐dimensional isoscapes. [ABSTRACT FROM AUTHOR]

Theoretical and empirical studies often show that within populations, individuals vary in their propensity to disperse. We aspired to understand how this behavioural variation is impacted by the distribution and pattern of food patches across a landscape. In a series of experiments we examined how inter‐patch distance and the distribution of food patches influenced dispersal in wild‐type strains of Drosophila melanogaster with natural allelic variants of the foraging (for) gene known to influence dispersal in this species. The 'rover' strain was homozygous for the forR allele (more dispersive) whereas the 'sitter' strain was homozygous for fors (less dispersive). We also assessed an outbred population of flies with an unknown dispersal propensity. Dispersal was assayed in a multi‐patch lab arena (25 cells, 5 × 5 array). In the inter‐patch distance trials, landscapes of two different sizes (small versus large) were used, both with food in all 25 cells. Dispersal was reduced in the large landscape relative to the small landscape for all three fly strains. Sitter dispersal was lowest relative to both rovers and the outbred flies, whose dispersal tendencies were similar. In the patch distribution trials, flies were assayed in landscapes with varying distribution and number of cells containing food. Dispersal generally increased as the number of patches with food increased, however, rovers and sitters adopted similar dispersal strategies when food was fixed and limited. Conversely, their strategies differed when the total amount of food increased with the number of patches. We find that both the inter‐patch distance and distribution can influence dispersal. However, the effect of inter‐patch distance and distribution on dispersals depends on genotype × environment interaction. Our findings highlight the importance of considering G × E when assessing how dispersal strategies and landscape dynamics influence the distribution of animal communities. [ABSTRACT FROM AUTHOR]

In this work, we have developed photoconductor devices based on Al0.39In0.61N layers grown on sapphire by reactive radio-frequency magnetron sputtering. The fabricated devices show a sublinear dependence of the photocurrent as a function of the incident optical power. The above-the-band-gap responsivity reaches 7 W/A for an irradiance of 10 W/m2 (405 nm wavelength). The response decreases smoothly for below-the-bandgap excitation, dropping by more than an order of magnitude at 633 nm. The devices present persistent photoconductivity effects associated to carrier trapping at grain boundaries. [ABSTRACT FROM AUTHOR]

Most reviews of stream fish connectivity have highlighted the urgent need for standardized methods to quantify the effects of barriers such as road crossings on fish movement and incorporate the complexity of fish behaviours. A question that has not been fully addressed yet in field assessments of fish stream connectivity is which conditions influence the detectability of road crossing effects. Failure to detect existing road crossing effects can result from shortcomings in sampling design that lead to low statistical power., Here, we propose general barrier dispersal models to allow for asymmetry in barrier permeability and changes in movement behaviours of fish confronting a barrier. Despite the increased realism of these ecological assumptions, it remains to be determined whether asymmetric barriers and altered movement behaviours can be unambiguously detected using mark-recapture trials. We used simulations within a modelling framework that explicitly incorporates barrier and behavioural effects to assess the statistical power of various mark-recapture sampling designs under different combinations of design and ecological constraints., Key insights from our simulations are that (i) the spatial extent of the study reach critically affects detectability of barrier effects; (ii) the number of recaptured individuals that cross a barrier has greater effect on detectability than the total number of recaptures on both sides of the barrier; and (iii) detectability of asymmetry in barrier permeability and of altered movement behaviours increases with both linear fish density and effect size., Synthesis and applications. The proposed dispersal models, incorporating asymmetric barrier permeability and changes in movement behaviours of fish confronting a barrier, are of broad importance in the quantification of habitat connectivity in streams and rivers. Our simulation approach provides precise guidelines for improving the sampling design by adjusting the spatial extent of the study reach based on a priori knowledge of ecological constraints. This study highlights the importance of evaluating the detectability of the effects of barriers such as road crossings and carefully planning the sampling design of mark-recapture studies before conducting costly field trials and provides quantitative tools to help achieve these goals. [ABSTRACT FROM AUTHOR]

We present an overview of the recently developed III-nitride-based optical waveguides for application in ultrafast signal processing at telecom wavelengths. We focus on different active and passive optical devices for further implementation within all-optical integrated circuits. Optical waveguides based on GaN/AlN quantum dots have been demonstrated to act as saturable absorbers requiring ∼3 pJ of input pulse energy to reach +3 dB transmittance contrast for TM-polarized light. On the contrary, sputtered-InN-based devices show −3 dB transmittance contrast associated to two-photon absorption for input pulse energies of ∼1 pJ, making them suitable to act as highly-efficient reverse saturable absorbers. Finally, the passive optical nature of waveguides based on sputtered AlN at 1.55 μm makes them suitable for further connections between different III-nitride-based active devices. [ABSTRACT FROM AUTHOR]

Macroecological comparisons have shown that habitat characteristics have a major influence on the evolution of life-history strategies of fishes in large river systems. Specifically, habitat variability and predictability seem to forge the reproductive strategies of fishes into a trilateral continuum with three main types: seasonal, opportunistic and equilibrium., Despite the usefulness of such a broad categorisation, large-scale patterns of trait distribution should ultimately be influenced by selection at smaller (i.e. individual) spatial scales. However, the scarcity of studies developed at the organismal scale leaves gaps in our understanding of how habitat characteristics affect life history and behavioural tactics of stream fishes., We examined the fine-scale spatial distribution of fishes in pristine Amazonian headwater streams over a full seasonal cycle to test whether segregation into main channel and associated temporary pond habitats was predictably related to hydrological variation and species' life-history traits., Most species could not be unambiguously assigned to one of the three end points of the trilateral continuum, but seemingly occupied instead the intermediate multivariate space between the end points. However, species were clearly ordered along a gradient of relative habitat use, ranging from strict channel dwellers throughout the hydrological cycle to pond specialists, with some species occupying the ponds at high water levels. Hydrological effects on habitat use were significantly related to species' reproductive strategies, with the strongest responses found in species with large eggs and seasonally concentrated reproduction, which were most abundant in ponds at high water levels., We suggest that trophic limitations and hydrological characteristics of Amazonian headwater forest streams may severely limit the seasonal strategy, one of the end points of the trilateral model. The species-specific habitat segregation reported here adds to the list of mechanisms, such as miniaturisation and isolation by distance, previously postulated to contribute to high diversity of stream fish faunas in the Amazon basin. [ABSTRACT FROM AUTHOR]

Aim We investigated the relationship between geographic range size ( GRS), longitude and latitude ( Rapoport's rule) in Canadian freshwater fishes. We tested hypotheses regarding the phenotypic and phylogenetic determinants of GRS to unravel processes driving the spatial patterns of GRS in Canada. Because GRS is negatively correlated with extinction risk, we also aimed at identifying biological proxies that may be used to predict extinction risks. Location North- America, Canadian Shield. Methods We built a database combining range area, seven ecological traits, and a molecular phylogeny for native Canadian freshwater fishes. We tested latitudinal and longitudinal patterns in GRS by the mean of Pearson correlations. We combined phylogenetic generalized least squares (PGLS) models and a model selection procedure to tease apart hypotheses (and hence ecological traits) that best explained GRS in our dataset. PGLSs were also used to explore relationships between ecological traits, phylogeny, and species mid-range latitude and longitude. Partial regressions were used to determine direct and indirect relationships driving spatial patterns of GRS in Canadian freshwater fishes. Results There was a significant and positive correlation between GRS, latitude and longitude. According to PGLSs, three ecological traits, related to the habitat use, migratory and thermal tolerance hypotheses, were significantly correlated with GRS, mid-range longitude and mid-range latitude. Two traits related to locomotion were further related to GRS. There was no phylogenetic effect on GRS (i.e. no phylogenetic conservatism). Partial regressions revealed complex direct and indirect relationships between ecological traits, mid-range latitude, mid-range longitude and GRS. Main conclusions Our results show that traits related to the ability to use dispersal corridors, as well as traits directly related to mobility, are useful in understanding biodiversity patterns such as Rapoport's rule. However, because of a weak explanatory power, we conclude that using biological proxies of GRS to predict species at risk of extinction would be premature. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the modeling framework based on dispersal kernels which describes stream fish dispersal. The study uses mark-recapture trials to measure summer dispersal of brook trout or Salvelinus fontinalis in four streams. The study reveals that the proposed modeling framework expands the dispersal kernels by integrating structural barriers.

1. Dispersal can be a major determinant of the distribution and abundance of animals, as well as a key mechanism linking behaviour to population dynamics, but progress in understanding dispersal has been hampered by the lack of a general framework for modelling dispersal. 2. This study tested the capacity of simple models to summarize and predict the lake-wide dispersal of an emerging cohort of young-of-the-year brook charr Salvelinus fontinalis, over 12 surveys conducted during a 2-month period. 3. The models are based on two types of dispersal kernel, the normal distribution from a simple diffusion process, and a Laplace distribution depicting exponential decay of the frequency of dispersers away from the point of origin. In all, four models were assessed: one-group diffusion (D1S) and exponential (E1S) models assuming homogeneous dispersal behaviour within the cohort, and two-group diffusion (D2S) and exponential (E2S) models accounting for intrapopulation differences in dispersal between sedentary and mobile individuals. 4. A rigorous cross-validation, based on calibrating the models to the distributions from the first two surveys only and then validating them on the remaining 10 distributions, was used to compare model predictions with observed values for five properties of the dispersal distributions: counts in individual shoreline sections; mean lateral displacement, variance and kurtosis of displacements; and the percentage of long-distance dispersers. 5. Substantial intrapopulation heterogeneity in dispersal behaviour was apparent: 83% of all individuals were estimated to be sedentary and the remainder mobile. Remarkably, the two-group exponential model E2S – calibrated to data from only two surveys conducted 3·5 and 8·5 days after the beginning of emergence – predicted reasonably well all properties of the spatial distribution of the cohort until the end of the study, 7 weeks later. 6. Standardized measures of mobility derived from simple models may lead to better understanding of population dynamics and improved management. Specifically, the ability to accurately predict long-distance dispersal may be critical to assessing population persistence and cohort strength whenever key habitats, such as refugia or productive areas supporting a large proportion of the cohort, are sparsely distributed or distant from the point of origin. [ABSTRACT FROM AUTHOR]

1. Forestry activities can greatly modify the structure and function of invertebrate communities in streams, but the ability to detect effects of forestry may depend on the spatial scale considered, the choice of response metric and the environmental context. In this study, a multi-scale, multi-metric approach was used to compare the usefulness of proximate and larger-scale measurements of forestry activity for understanding the impacts of forestry on stream macrobenthos. 2. Site-specific responses of macrobenthic communities to forestry activities measured at four spatial scales (sub-basin and 8-, 2- and 0.5-km radii upstream of study sites) were examined for 90 riffle sites distributed among 22 tributary streams (Strahler order 1–5) of the Cascapedia River basin, Quebec, Canada. 3. Multiple regression models and canonical correspondence analysis were used to relate six biological metrics (taxonomic richness, numerical density, biomass density, normalised biomass spectrum, individual body mass and community structure) to variables quantifying logging 1–19 years prior to the study and road density. Environmental predictors (variables quantifying local habitat or landscape features) were included in all analyses to statistically account for environmental context and increase the likelihood of detecting potentially subtle forestry impacts. 4. Forestry activities measured at the larger (sub-basin and 8 km) scales were linked to decline in taxonomic richness, increase in numerical and biomass densities and shift in size structure of benthic macroinvertebrates, indicating that analyses encompassing larger areas, up to the full basin, may allow for more sensitive detection of effects than those of more limited span. 5. These responses primarily reflected marked increases in the abundance of chironomids and decline in the number of trichopteran taxa with increasing areal coverage of recent (≤2–4 years) cuts, suggesting that larger, longer-lived and possibly more specialised taxa were more vulnerable to forestry impacts than smaller, multivoltine, generalist invertebrates. After partialling out the influence of other variables, rapid decline in richness occurred even when <1% of the basin had been clear cut in the year prior to the study. 6. Effects of forestry were detected after statistically accounting for natural environmental variability, which may have otherwise concealed those effects. The combined use of multiple biological metrics, partialling out of environmental effects and measurement of impacts at multiple spatial scales may be a broadly applicable approach for enhancing sensitivity and facilitating interpretation in studies of anthropogenic effects on macroinvertebrate communities. [ABSTRACT FROM AUTHOR]

1. We compared the capacity of logistic regression (LR) and classification tree (CT) models to predict microhabitat use and the summer distribution of juvenile Atlantic salmon,Salmo salar, in two reaches of a small stream in eastern Quebec.2. The models predicted the presence or absence of salmon at a location on the basis of habitat features (depth, current velocity, presence of instream and overhead cover, substratum particle size, and distance to stream bank) measured at that location. Models were validated by means of crossover field tests evaluating the performance of models developed for one reach (calibration trials) when applied to the other reach (validation trials). Model performance was evaluated with regard to accuracy, generality and ease of use and interpretation. Prediction maps based on habitat features were also built to compare the observed position of fish with those predicted by LR and CT models.3. The spatial distribution of active fish differed markedly from that of resting fish, apparently as a result of the selection for water greater than about 30 cm depth by active fish and for the presence of rocky cover by resting fish.4. All models made accurate predictions, validated by crossover trials. For both LR and CT models, the prediction maps reflected well the actual fish distributions. However, CT models were easier to build and interpret than LR models. CT models also had less variable performance and a smaller decline in predictive capability in crossover trials (for fish at rest), suggesting that they may be more transferable than LR models. [ABSTRACT FROM AUTHOR]

1. Movements between a stream reach and two adjacent lentic macrohabitats, a beaver pond and a lake, were followed for the Appalachian crayfish and two fish species, brook charr and brown bullhead, over an 85-d period from early June to late August, and were analysed in relation to water level, maximum water temperature, photoperiod length, lunar luminosity, and age, by use of time-series regressions. 2. Brook charr showed strong net immigration to the stream reach for underyearling (age class 0+) fish but net emigration for 1+ fish. Both immigration and emigration were positively related to water level and temperature; migratory responses to temperature were age-specific. 3. Brown bullhead used the stream primarily as a corridor for downstream migration from the beaver pond to the lake. As with brook charr, water level and temperature had a positive effect on movement and responses were stronger in younger individuals. 4. Crayfish emigrated from the stream during the summer. Movements were positively related to increases in water level and temperature, with responses of 1+ crayfish much stronger than those of older individuals. 5. The results indicate that the stream tributary played different roles for brook charr (nursery), brown bullhead (dispersal corridor) and Appalachian crayfish (early summer refuge), and suggest that variation in water level or temperature resulting from climatic change or local anthropogenic activities might modify connectivity between macrohabitats, particularly for younger individuals. [ABSTRACT FROM AUTHOR]

Investigates restricted movement in stream fish. Measures of mobility; Relationship between turnover and displacement; Characteristics of intra-population variation in mobility; Factors influencing population dispersal.

The influence of the AlInN thickness (65–145 nm) on the photovoltaic characteristics of In‐rich n‐AlxIn1−xN (x ≈0.38–0.42) on p‐Si(111) heterojunctions deposited by radio frequency sputtering has been reported. All samples show a closely packed columnar morphology with a root mean‐squared surface roughness below 3.7 nm and an apparent optical bandgap energy of ≈2.0 eV. Dark current density–voltage curves of the solar cell devices based on the developed AlInN/Si(111) heterojunction reveal shunt and series resistances in the range of 1.3–5.0 kΩ and 7.7–16.2 Ω depending on the AlInN thickness, respectively. Their photovoltaic performance shows an enhancement with the AlInN thickness, with an increase of the short circuit current and conversion efficiency from 16 to 19 mA cm−2 and from 1.8 to 2.5% under one‐sun AM1.5G illumination. At the same time, the open circuit voltage and the fill factor remain at ≈0.34–0.40 V and ≈30–37%, respectively. These effects are due to the enhanced optical transmittance of the AlInN layer in the wavelength range in which the maximum of the Si spectral photoresponse occurs, in agreement with the increased responsivity of the devices at 950 nm of 450 mA W−1. These results demonstrate the feasibility of using In‐rich AlInN alloys deposited by radio frequency sputtering as n‐type layer of AlInN/p‐type Si heterojunction solar cells. This paper reports the influence of the AlInN thickness on the photovoltaic characteristics of In‐rich n‐AlInN/p‐Si(111) heterojunctions deposited by RF sputtering. The photovoltaic performance enhances with the AlInN thickness, achieving an efficiency record value around 2.5%. These results demonstrate the feasibility of using In‐rich AlInN alloys deposited by RF sputtering as n‐type layer of AlInN/p‐type Si heterojunction solar cells. [ABSTRACT FROM AUTHOR]

The article presents a case study of a non-atopic 27-year-old Arab woman who attended to the Allergy Department due to the episodes of facial edema. The patient was recommended to avoid using oral contraceptives (OCs) which lead the occurrence of the episodes while the patients' biochemical parameters and complete blood count were in normal range. The patients' clinical diagnosis is a hereditary angioedema (HAE) type III associated with XII gene missense mutation in a family of Arab origin.

Summary 1. Habitat degradation and fragmentation are growing concerns in ecology, yet distinguishing between the effects of these processes can be a challenging task. In riverine landscapes, roads impact fish populations mainly through: (i) restriction of passage of individuals (fragmentation) and (ii) reduction in habitat quality downstream by increases in sediment load (habitat degradation). These two processes can be differentiated during road construction projects. 2. This study examines the impacts of a highway expansion and the presence of existing highway crossings on local population density of brook charr Salvelinus fontinalis in stream reaches traversed by the highway. Density was estimated on three consecutive summers in 212 sections distributed among 36 streams. This extensive sampling design focused on replicated comparison of sites upstream and downstream of highway crossings and included different stages of highway construction (before, during and after) and types of highway crossing (low, intermediate and high passability). Mixed models were used to examine the impacts of the highway on population density. 3. Highway construction activities had no detectable effect on density. However, existing highway crossings appeared to have a strong effect on density, which differed markedly between upstream and downstream sites near highway crossings of intermediate and low passabilities. 4. A Markovian movement model yielded estimates of passability that were consistent with the classification of crossing types and provided evidence for the restriction of upstream movement at crossings as a plausible explanation for observed differences in local population density. 5. Synthesis and applications. Habitat fragmentation resulting from restriction of passage at highway crossings had markedly greater effects on local population density than short-term impacts arising from construction activities. The modelling approaches used in this study can be useful management tools for the conservation of mobile fish species in fragmented riverine landscapes. [ABSTRACT FROM AUTHOR]