Drift Samples Research Articles

AWS-DAIE: Incremental Ensemble Short-Term Electricity Load Forecasting Based on Sample Domain Adaptation

Short-term load forecasting is a prerequisite and basis for power system planning and operation and has received extensive attention from researchers. To address the problem of concept drift caused by changes in the distribution patterns of electricity load data, researchers have proposed regular or quantitative model update strategies to cope with the concept drift; however, this may involve a large number of invalid updates, which not only have limited improvement in model accuracy, but also insufficient model response timeliness to meet the requirements of power systems. Hence, this paper proposes a novel incremental ensemble model based on sample domain adaptation (AWS-DAIE) for adapting concept drift in a timely and accurate manner and solves the problem of inadequate training of the model due to the few concept drift samples. The main idea of AWS-DAIE is to detect concept drift on current electricity load data and train a new base predictor using Tradaboost based on cumulative weighted sampling and then dynamically adjust the weights of the ensemble model according to the performance of the model under current electricity load data. For the purposes of demonstrating the feasibility and effectiveness of the proposed AWS-DAIE algorithm, we present the experimental results of the AWS-DAIE algorithm on electricity load data from four individual households and compared with several other excellent algorithms. The experimental results demonstrated that the proposed AWS-DAIE not only can adapt to the changes of the data distribution faster, but also outperforms all compared models in terms of prediction accuracy and has good practicality.

Predicting drift characteristics of life rafts: Case study of field experiments in the South China Sea

Every year, hundreds of people die at sea because of vessel and airplane accidents. As marine emergency evacuation equipment, life rafts are highly used in case of maritime accidents. Accurate predictions of drift trajectories and search and rescue (SAR) areas for life rafts at sea can enhance the efficiency and success rate of maritime SAR operations to save human lives. The objective of this study is to determine the drift characteristics of aviation and marine life rafts in the South China Sea, and develop an accurate drift prediction model. A series of maritime drift experiments were conducted in the South China Sea using the standard 6-person life raft (aviation life raft) and the standard 10-person life raft (marine life raft) to obtain 550 drift samples. This data was used to establish three drift models of life rafts: the AP98 leeway drift model, the dynamics drift model and the improved drift model. Finally, Lagrangian particle tracking method and Monte Carlo simulations were used to compare the drift models for 6-person and 10-person life raft. Results indicate that the probability of positive crosswind leeway (CWL) for 6-person and 10-person life raft is 61% and 31.4%, respectively. The jibing frequency is 2% per hour for 6-person and 4% per hour for 10-person life raft. The maximum divergence angle is 11.3° for 6-person and 20.5° for 10-person life raft, indicating that 10-person life raft is more sensitive to the wind speed in the crosswind direction. The improved drift model is more accurate than AP98 leeway drift model and dynamics drift model for predicting drift trajectories of both 6-person and 10-person life rafts. The results of this work may provide effective guidance for drift prediction of aviation life rafts and marine life rafts, which is of great significance for the maritime search and rescue (SAR) operations in the South China Sea.

The overlooked contribution of a fish bypass channel to the density and diversity of macroinvertebrate drift in a heavily modified river system

AbstractThe freshwater biodiversity decline affects all trophic levels, prompting restoration efforts. While habitat restoration for fish is well‐studied, habitat restoration to benefit other sensitive taxa such as Ephemeroptera, Plecoptera, and Trichoptera (EPT) remains poor. Consequently, this study investigated the habitat function of a man‐made nature‐like bypass system for EPT taxa in a highly modified alpine river with several drift feeding fishes. Spatially and temporally distributed drift samples were used to test the hypotheses that the bypass (a) enhances the density of drifting individuals compared to the main river and (b) diversifies drift assemblages compared to the main river. Mean drift density of EPT taxa was lowest in the main stem of the river close to the inlet of the bypass (38.24 Ind./100m3) and significantly increased toward the downstream direction of the bypass, near the outflow (61.49 Ind./100m3). In addition, drift assemblages significantly changed from the main stem to the bypass and the number of EPT taxa detected more than doubled (main stem: 16 genera; last site in the bypass: 33 genera), indicating that the bypass can provide a macroinvertebrate source to the main stem. Seasonal and diel drift patterns were similar to those observed in natural streams, underpinning the finding that nature‐like bypass systems can feature an EPT community similar to natural rivers. This study aligns with a growing body of evidence on the habitat function of nature‐like bypass systems for aquatic taxa and highlights the importance of this restoration measure beyond the aspect of solely restoring habitat connectivity.

Comparison of Water Sensitive Paper and Glass Strip Sampling Approaches to Access Spray Deposit by UAV Sprayers

Target and off-target spray depositions determine the spray’s effectiveness and impact on the environment. A decisive stage in the measurement of spray deposition and drift is selecting an appropriate sampling approach under field conditions. There are various approaches available for sampling spray deposition and drift, during the evaluation of ground sprayers used for the UAV sprayer assessment, under field conditions. In this study, two sampling approaches (water-sensitive paper, and glass strip collectors) were compared to analyze spray deposition in target and off-target zones. The results showed a variation in the estimation of the spray deposits among the two applied sampling methods. The results showed that the water-sensitive paper recorded the droplet deposition in the target zone with a range from 0.049 to 4.866 µLcm−2, whereas the glass strip recorded from 0.11 to 0.793 µLcm−2. The results also showed the water sensitive paper recorded an 80.3% higher deposition than that of the glass strip at zero position during the driving flight height 2 m and flight speed 2 ms−1 (T1 treatment). It can be concluded that variation in recorded depositing is due to the sampling material. It is recommended that the confident deposition results, measurement methods and sampling approaches must be standardized for UAV sprayers according to the field conditions and controlled within artificial assessments.

Distinguishing Biological Trends from Adaptation

Models of evolution commonly decompose change into deterministic and stochastic components. Different models, however, produce different concepts of signal and noise. Excursion tests correct for two distinct types of noise, sampling error and phenotypic drift, resulting in two distinct types of signal or trend. A minimal trend is a signal of historical change after correcting for sampling error; a directed trend is a model dependent measure of confidence that selection has occurred (correcting for both sampling error and drift). The history of random walks and excursion tests in paleobiology highlights the conceptual middle ground between historical pattern and underlying processes. In paleobiology, both minimal and directed trends reflect a causally agnostic, trait-level product of evolutionary and environmental processes. Directed trends provide evidence for directional causes, but the identity and relative strength of those causes requires a deeper understanding. Thus, the magnitude of minimal and directed trends should not be interpreted as the strength of selection for a specified trait. They can be a useful stepping stone in that direction when paired with a map of the middle ground and agreement about how genetic, macroevolutionary, and environmental processes contribute to evolutionary change.

Drift-Proof Tracking With Deep Reinforcement Learning

Object tracking is an essential and challenging sub-domain in the field of computer vision owing to its wide range of applications and complexities of real-life situations. It has been studied extensively over the last decade, leading to the proposal of several tracking frameworks and approaches. Recently, the introduction of reinforcement learning and the Actor-Critic framework has effectively improved the tracking speed of deep learning trackers. However, most existing deep reinforcement learning trackers experience a slight performance degradation mainly owing to the drift issues. Drifts pose a threat to the tracking performance, which may lead to losing the tracked target. Herein, we propose a drift-proof tracker with deep reinforcement learning that aims to improve the tracking performance by counteracting drifts while maintaining its real-time advantage. We utilize a reward function with the Distance-IoU (DIoU) metric to guide the reinforcement learning to alleviate the drifts caused by the trained model. Furthermore, double negative samples (hard negative and drift samples) are constructed in tracking for network initialization, which is followed by calculating the loss by a small error-friendly loss function. Therefore, our tracker can better discriminate between the positive and negative samples and correct the predicted bounding boxes when the drift occurs. Meanwhile, a generative adversarial network is adopted for positive sample augmentation. Extensive experimental results on multiple popular benchmarks show that our algorithm effectively reduces the occurrences of drift and boosts the tracking performance, compared to those of other state-of-the-art trackers.

Spatial and Temporal Patterns of Pelagic Catfish Larvae Drifting in Lowland Rivers of Eastern Ecuador (Pisces: Siluriformes)

This study investigated larval catfish abundance and diversity in various fluvial habitats in the Amazon lowlands of eastern Ecuador. It assessed the relationship between spawning behavior and the hydrological cycle, identified a potential spawning site, and elucidated community assemblages based on larval diversity among river tributaries with differing water chemistry profiles. Sampling sites included the mainstreams of the Napo and Aguarico Rivers and lower reaches of three tributaries. Drift samples were taken before, during, and after strong, rain-induced flooding occurred. Results suggest a strong peak of larval abundances in April, coinciding with the start of the flood period. In the Napo mainstream, samples were dominated by larvae of large migratory pimelodid catfishes, Pseudoplatystoma spp., which were caught between the upriver site in the foothills (254 m a.s.l.) and the downstream Peruvian frontier (175 m a.s.l.). Back-calculations based on water velocity and larval growth rate suggest that most of these larvae originated in the lowlands between those two locations, where the riverbed transitions from rocky to sandy/silty substrate. Thus, it appears that most spawning occurred over sandy substrates rather than the rocky substrates that were dominant above the upriver site. Comparisons of samples taken by day and night at the same sites revealed significantly higher larval abundances at night; thus, larvae must either preferentially drift at night, actively avoid the nets by day, or may do diel vertical migrations (e.g., related to predation pressure or pursuit of prey items). Dominant larval taxa in the whitewater mainstreams differed from those dominating samples from a blackwater mainstream system, and catfish larval assemblages in each of those habitats were distinct from those drifting in small, blackwater tributaries. These results provide key life-history information for catfish species in the Napo River, including for important commercial species, such as Pseudoplatystoma spp. Identification and protection of discrete spawning sites, such as those identified here, are critical to conservation efforts for these species.

Wasted effort or promising approach – Does it make sense to build an engineered spawning ground for rheophilic fish in reservoir cascades?

Anthropogenic alterations such as the construction of dams and reservoirs led to a loss of quantity, quality and connectivity of habitats for riverine fish species. The resulting decline of freshwater fishes has prompted many restoration efforts addressing bottlenecks in their life cycles such as improving spawning habitat quality. Whilst there is a wealth of studies addressing the benefits and challenges of spawning ground restoration for rheophilic fishes in lotic ecosystems, there is a paucity of information on the usefulness of such measures in almost lentic systems. In this study, an engineered spawning ground with areas of different grain sizes, built as a mitigation measure for a hydropower plant construction in a near-stagnant reservoir cascade, was assessed including physical and chemical characterisation, spawning habitat use and recruitment of target species for conservation. During the six-week investigation period, about 4000 larvae and 18,000 eggs of mainly ubiquitous species such as roach (Rutilus rutilus, L.) and European perch (Perca fluviatilis, L.) were detected by drift netting and sampling of the gravel bed. The engineered spawning ground was successfully used for recruitment by the rheophilic gravel spawning cyprinids asp (Leuciscus aspius, L.) and ide (Leuciscus idus, L.). For all species, the highest density of eggs and larvae was found in the area with the highest current velocity directly at the turbine outlet. The findings of this study illustrate the potential of engineered spawning grounds for fish conservation even in heavily modified water bodies such as reservoir cascades. However, evidence of successful reproduction of rheophilic species on the spawning ground alone does not allow any predictions on further population development, since crucial prerequisites in the further ontogeny may pose additional bottlenecks.

Spray drift deposition comparison of fluorimetry and analytical confirmation techniques.

Tracer dyes are often used as surrogates to characterize pesticide spray drift and it is assumed that they accurately reflect analytical measurement of active ingredients; however, the validity of this assumption remains inconclusive. Consequently, the influence of measurement technique on the magnitude of deposition of spray drift was investigated using spray drift samples evaluated by traditional analytical techniques (HPLC-MS/MS) and fluorimetry (1,3,6,8-pyrene-tetra sulfonic acid tetrasodium salt dye tracer). The experiment was conducted in a low-speed wind tunnel under controlled meteorological conditions. The herbicide mesotrione was sprayed through three spray air induction nozzles (anvil deflector flat fan TTI11004; flat fan AI11004; flat fan AIXR11003). Spray drift deposition samples were collected using stainless steel discs pairs placed side by side in the center of the wind tunnel at distances of 5, 10, 20, 30, and 40 ft (1.5, 3.1, 6.1, 9.1, and 12.2m) from the spray nozzle. The analytical technique determined pesticide concentration on one disc per pair, and the other was evaluated by fluorimetry. The experimental results, analyzed using the linear split-split plot model, revealed that median deposition concentrations were 15% higher using the tracer dye fluorescence method relative to the analytical method, potentially due in part to procedural recovery inefficiencies of the analytical method (the mean overall procedural recovery result and RSD was 87% ± 6.4% (n=12). This relationship was consistent and held true for the three nozzle types at all distances within the wind tunnel. © 2021 Society of Chemical Industry.

Phylogeographic structure and population connectivity of a small benthic fish (Tripterygion tripteronotum) in the Adriatic Sea

AbstractAimPopulation connectivity of benthic marine organisms depends strongly on planktonic larval dispersal and is controlled by geographic distance and oceanographic structure. We examine isolation by distance versus resistance to barriers (ocean current boundaries) against a background of post‐glacial habitat expansion in a small benthic fish of the Adriatic Sea.LocationAdriatic Sea, Eastern Mediterranean.TaxonTripterygion tripteronotum.MethodsWe performed population genetic analyses using mitochondrial control region sequences of 550 individuals from 25 locations sampled along the Eastern Adriatic coast. Investigations of population structure included differentiation tests, cluster analyses and distance‐based redundancy analysis. We then ran Lagrangian simulations of passive larval drift to examine correlations among population structure, geographic distance and the Adriatic gyre system. To test for signatures of a post‐glacial range expansion, we modelled the demographic history of the populations and examined the geographic distribution of genetic diversity.ResultsGenetic population structure corresponded to the Adriatic gyres without additional effect of geographic distance. Inference of northward‐biased gene flow between the northern and the Istrian gyre was consistent with simulated trajectories of passive drift, whereas the phylogeographic break coinciding with the boundary between the Central and the Northern Adriatic gyre was stronger than predicted by drift simulations. Genetic connectivity of populations within gyres was high. Genetic signatures of population expansion were consistent with a rapid post‐glacial recolonization of the northern Adriatic.Main conclusionsThe combination of dense sampling and passive drift simulation allowed us to distinguish among effects of geographic distance, oceanographic features and palaeoenvironmental changes on current population structure. Comparisons between realized and potential connectivity illustrate the value of integrating different data sources to understand population structure and inform conservation planning.

Sampling schemes and drift can bias admixture proportions inferred by structure.

The interbreeding of individuals coming from genetically differentiated but incompletely isolated populations can lead to the formation of admixed populations, having important implications in ecology and evolution. In this simulation study, we evaluate how individual admixture proportions estimated by the software structure are quantitatively affected by different factors. Using various scenarios of admixture between two diverging populations, we found that unbalanced sampling from parental populations may seriously bias the inferred admixture proportions; moreover, proportionally large samples from the admixed population can also decrease the accuracy and precision of the inferences. As expected, weak differentiation between parental populations and drift after the admixture event strongly increase the biases caused by uneven sampling. We also show that admixture proportions are generally more biased when parental populations unequally contributed to the admixed population. Finally, with few exceptions, using a large number of markers reduces those biases, but using alternative priors for individual ancestry or the uncorrelated allele model only marginally affect the inference of admixture in most situations. We conclude that unbalanced sampling may cause important biases in the admixture proportions estimated by structure, especially when a small number of markers are used, and those biases can be worsened by the effect of drift and unequal genetic contribution of parental populations. Empirical studies should thus be careful with their sampling design and consider historical characteristics when using this software to estimate the ancestry of individuals from admixed populations.

Assessment of HF Radar in Mapping Surface Currents under Different Sea States

AbstractTwo Ocean State Monitoring and Analyzing Radar (OSMAR071) (7.8 MHz) high-frequency (HF) radars and four moored ADCPs were operated concurrently in the southwestern Taiwan Strait during January–March 2013. Qualitative and quantitative comparisons of surface currents were conducted between the HF radars and the ADCPs. Except for a location probably affected by shallow water and sand waves on the Taiwan Banks, the HF-radar-derived radial currents (radials) showed good agreement with the ADCP measured results (correlation coefficient: 0.89–0.98; rms difference: 0.07–0.13 m s−1). To provide further insight into the geophysical processes involved, the performance of the HF-radar-derived radials was further evaluated under different sea states (sea states: 2–6). It was found that both the data returns of the radar-derived radials and the differences between the radar-derived radials and the ADCP-derived radials varied with sea state. The HF radar performed best at sea state 4 in terms of data returns. The spatial coverage increased rapidly as the waves increased from sea state 2 to 4. However, it decreased slowly from sea state 4 to 6. Second, the radial differences were relatively high under lower sea states (2 and 3) at the location where the best agreement was obtained between the radar and ADCP radials, whereas the differences increased as the sea states increased at the other three locations. The differences between the radials measured by the HF radars and the ADCPs could be attributed to wave-induced Stokes drift and spatial sampling differences.

A field system for measuring plant and soil carbon fluxes using stable isotope methods

AbstractThere is a lack of field methods for measuring plant and soil processes controlling soil organic matter (SOM) turnover over diurnal, seasonal and longer timescales with which to develop datasets for modelling. We describe an automated field system for measuring plant and soil carbon fluxes over such timescales using stable isotope methods, and we assess its performance. The system comprises 24 large (1‐m deep, 0.8‐m diameter) cylindrical lysimeters connected to gas‐flux chambers and instruments. The lysimeters contain intact, naturally structured C3 soil planted with a C4 grass. Fluxes of CO2 and their 13C isotope composition are measured three times daily in each lysimeter, and the isotope composition is used to partition the fluxes between plant and soil sources. We investigate the following potential sources of error in the measurement system and show they do not significantly affect the measured CO2 fluxes or isotope signatures: gas leaks, the rate of gas flow through sampling loops, instrument precision and drift, the concentration dependence of isotope measurements, and the linearity of CO2 accumulation in the chambers and associated isotope fractionation resulting from different rates of 13CO2 and 12CO2 diffusion from the soil. For the loamy grassland soil and US prairie grass (Bouteloua dactyloides) tested, the precision of CO2 flux measurements was ±0.04% and that of the flux partitioning ±0.40%. We give examples of diurnal and seasonal patterns of plant and soil C fluxes and soil temperature and moisture. We discuss the limitations of the isotope methodology for partitioning fluxes as applied in our system. We conclude that the system is suitable for measuring net ecosystem respiration fluxes and their plant and soil components with sufficient precision to resolve diurnal and seasonal patterns.Highlights We describe an automated system for measuring plant and soil carbon fluxes under field conditions. We exploit the large difference in isotope signatures between C3 and C4 soils and plants to partition the net flux. Possible sources of error are quantified and shown to be small. The system is capable of resolving diurnal and seasonal patterns.

A VALIDATED METHOD FOR QUANTITATION OF PREGABALIN AND METHYLCOBALAMIN USING DIFF USE REFLECTANCE FTIR SPECTROSCOPY IN BULK AND COMBINED TABLET DOSAGE FORM

A Simple, accurate precise and validated FTIR method was developed for the determination ofpregabalin (PRG) and methylcobalamin (MCA) in bulk as well as in tablet dosage form. The drug was analyzed by FTIR spectrophotometry with DRIFT sampling technique. wavenumber ranges 1660-1600 cm-1 (-COOH) and3400-3250 cm−1(-CONH2) were selected for pregabalin and methylcobalamin, respectively. The method was found to be linear over the range of PRG 1–6% w/w and MCA 0.2–1.2% w/w with good regression coefficient (r2) of PRG 0.9960 and MCA 0.9976. The percent recovery of pregabalin and methylcobalamin in marketed tablet dosage form was in the range of 98.25 – 99.00% and 98.62 – 99.60%, respectively. The LOD & LOQ were found 1.4003 & 4.2434 of PRG and 0.2027 & 0.6142 of MCA, respectively.The developed FTIR method was validated as per ICH guidelines and it can be used for the estimation of both drugs in combined dosage form.

Herbal Medicine Characterization Perspectives Using Advanced FTIR Sample Techniques - Diffuse Reflectance (DRIFT) and Photoacoustic Spectroscopy (PAS).

This study demonstrates the significant potential of the Fourier transform infrared spectroscopy (FTIR) sampling methods: cantilever-enhanced Fourier transform infrared photoacoustic spectroscopy (FTIR PAS) and diffuse reflectance infrared spectroscopy (FTIR DRIFT) in the field of herbal medicines (HM). In the present work we investigated DRIFT and PAS sampling methods because they do not require sample preparation, samples may be opaque or dark, require small amounts, both liquid and solid samples can be measured, and solid samples can be analyzed on a small scale. Experiments conducted prove high sensitivity, reproducibility and capability in combination with an unsupervised multivariate analysis technique to discriminate important characteristics of HM, such as the identification of plant parts, differentiation of samples by types, and determination of the concentration of extractable compounds in HM.

New insights into larval lake sturgeon daytime drift dynamics

Drifting post yolk-sac (PYS) lake sturgeon Acipenser fulvescens larvae were believed to seek refuge in substrate during daytime although there were no data to support this theory. There is growing scientific literature on important habitat, such as for adults and where eggs are spawned and hatch, however a gap remains in understanding duration of drift for PYS larvae, especially during daytime. This study was undertaken to find drifting PYS lake sturgeon larvae during the day in the Sturgeon River, Michigan, a clear yet tannin-rich river with a well-studied self-sustaining population. River substrates were mapped, and light, velocity, and depth data gathered to describe ‘believed’ refuge for larvae during daylight. From 2013 through 2016 nighttime drift samples (n = 463) for PYS lake sturgeon larvae were complemented with 143 daytime kick net samples and 43 daytime drift sets. No drifting larvae were collected in the daytime kick nets covering a variety of substrate types while over 1,600 PYS larvae were captured in drift nets at night, and 34 were captured in daytime drift sets. These 34 PYS larvae were in the previously unsampled thalweg in ~5% of surface light and at velocities of 0.24 to 0.57 m/s. Data suggest that drifting PYS lake sturgeon larvae do not stop and seek refuge during daylight but rather drift quickly and continuously downstream until suitable habitat is encountered. Measures of light, depth, velocity and thalweg presence combined with LiDar and Sonar mapping will be critical to understanding river suitability and restoration success for this species.

Spray Drift from Three Airblast Sprayer Technologies in a Modern Orchard Work Environment.

Pesticide spray drift represents an important exposure pathway that may cause illness among orchard workers. To strike a balance between improving spray coverage and reducing drift, new sprayer technologies are being marketed for use in modern tree canopies to replace conventional axial fan airblast (AFA) sprayers that have been used widely since the 1950s. We designed a series of spray trials that used mixed-effects modeling to compare tracer-based drift volume levels for old and new sprayer technologies in an orchard work environment. Building on a smaller study of 6 trials (168 tree rows) that collected polyester line drift samples (n = 270 measurements) suspended on 15 vertical masts downwind of an AFA sprayer application, this study included 9 additional comparison trials (252 tree rows; n = 405 measurements) for 2 airblast tower sprayers: the directed air tower (DAT) and the multi-headed fan tower (MFT). Field-based measurements at mid (26 m) and far (52 m) distances showed that the DAT and MFT sprayers had 4-15 and 35-37% less drift than the AFA. After controlling for downwind distance, sampling height, and wind speed, model results indicated that the MFT [-35%; 95% confidence interval (CI): -22 and -49%; P < 0.001] significantly reduced drift levels compared to the AFA, but the DAT did not (-7%; 95% CI: -19 and 6%; P = 0.29). Tower sprayers appear to be a promising means by which to decrease drift levels through shorter nozzle-to-tree canopy distances and more horizontally directed aerosols that escape the tree canopy to a lesser extent. Substitution of these new technologies for AFA sprayers is likely to reduce the frequency and magnitude of pesticide drift exposures and associated illnesses. These findings, especially for the MFT, may fit United States Environmental Protection Agency's Drift Reduction Technology (DRT) one-star rating of 25-50% reduction. An 'AFA buyback' incentive program could be developed to stimulate wider adoption of new drift-reducing spray technologies. However, improved sprayer technologies alone do not eliminate drift. Applicator training, including proper sprayer calibration and maintenance, and application exclusion zones (AEZs) can also contribute to minimizing the risks of drift exposure. With regard to testing DRTs and establishing AEZs, our study findings demonstrate the need to define the impact of airblast sprayer type, orchard architecture, sampling height, and wind speed.

Determination of polioksin B in the air environment and in washouts from skin of operators by HPLC

Polyoxin B being an effective inhibitor of synthesis of chitin of the cell wall of many phytopathogenic fungi, is recommended as a fungicide for control of phytopathogenic organisms that cause damage to crop. For the determination of the exposure of employees working with pesticides there was developed the method of the measurement of concentrations of polyoxin B in air of working area, atmospheric air of populated areas and washouts from the operators ’ integuments, based on high performance liquid chromatography with ultraviolet detector (detection wavelength of270 nm), including sampling air environment in the sorption tube ORBO-44, filled with sorbent XAD-2, extraction of the sorbent with polyoxin by a mixture of carbinol-water (in a ratio of 95:5,on volume), washout from the surface of the skin with ethyl alcohol by way of washing, concentrating, quantitative chromatographic analysis. Lower limits of the quantification ofpolyoxin B in the air ofworking area - 0.2 mg/m at the aspiration of 2 dm of air, atmospheric air - 0.016 mg/m at the aspiration of 25 dm of air, in washouts from the operators’ integuments - 0.4 pg/wash, the linear range of the defined concentrations accounted for of 0.2 - 2.4 pg/cm, the total error of measurement of the concentrations of polyoxin B in air is 17%; in washouts from the operators’ integuments - 16%. The developed method was approbated for the determination of polyoxin in samples of air of working zone, atmospheric air within the sanitary gap, washouts from the operators ’ integuments and air drift samples taken under processing of roses in the hothouse and in the monitoring of the phytosanitary condition of the plants every other day after treatment.

Evaluating the impact of Permethrin on non-target invertebrates in an urban stream

Insecticides are broadly applied in many urban areas of the western United States to control mosquito populations and reduce the prevalence of diseases such as West Nile and Zika Virus. We assessed the extent to which incidental exposure to the insecticide Permethrin affected drifting and benthic invertebrates in Spring Creek, Laramie, WY, USA. We collected drift samples before, immediately after (~ 3–6 h), and 1 day after (~ 28 h) insecticide application. We collected benthic invertebrates with a Hess sampler twice before and twice after spraying began. We measured an 11 × increase in the density of drifting aquatic insects immediately after pesticide application. Additionally, we observed an increase in drifting aquatic invertebrates 2.25 km downstream from treatment. A decrease in the biomass of benthic invertebrates and an increase in taxa richness at the end of the summer suggested that invertebrates are colonizing the stream but may be unable to persist. Fewer aquatic invertebrates in the stream may have cascading effects on the ecosystem by altering resources available to fish and riparian insectivores (e.g., bats, spiders, and amphibians). Understanding the unintended ecological impacts of current pest control practices could lead to more effective and less detrimental management strategies.

A simple method for sampling invertebrate drift in large rivers and boulder‐bed streams

AbstractSampling invertebrate drift in high‐gradient boulder‐bed channels or large turbulent rivers is challenging, because the traditional approach of driving stakes into the stream bed to secure drift nets may not work. We describe a simple method using a split wading rod to collect drift samples from the wadeable river margin or bank as an alternative method for rapid assessment of invertebrate drift when boat access is not possible. Pilot sampling in a large river shows that near‐shore drift samples collected with this approach are broadly similar to samples collected from the centre of the channel using more conventional methods, although our results suggest that depth and velocity effects may cause drift concentrations to be elevated closer to the bank.