Behavioral responses of silver carp (Hypopthalmichthys molitrix), bighead carp (H. nobilis), and common carp (Cyprinus carpio) to a complex, broadband sound were tested in the absence of visual cues ...to determine whether these species are negatively phonotaxic and the roles that sound pressure and particle motion might play mediating this response. In a dark featureless square enclosure, groups of 3 fish were tracked and the distance of each fish from speakers and their swimming trajectories relative to sound pressure and particle acceleration were analyzed before, and then while an outboard motor sound was played. All three species exhibited negative phonotaxis during the first two exposures after which they ceased responding. The median percent time fish spent near the active speaker for the first two trials decreased from 7.0% to 1.3% for silver carp, 7.9% to 1.1% for bighead carp, and 9.5% to 3% for common carp. Notably, when close to the active speaker fish swam away from the source and maintained a nearly perfect 0° orientation to the axes of particle acceleration. Fish did not enter sound fields greater than 140 dB (ref. 1 μPa). These results demonstrate that carp avoid complex sounds in darkness and while initial responses may be informed by sound pressure, sustained oriented avoidance behavior is likely mediated by particle motion. This understanding of how invasive carp use particle motion to guide avoidance could be used to design new acoustic deterrents to divert them in dark, turbid river waters.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
An understanding of how undesirable and desirable fish species respond behaviorally to turbulent flow in fishways would guide development of selective fish passage techniques. We applied ...high-resolution computational fluid dynamics modeling and competing risks analysis towards the development of predictive selective passage models. Sea lamprey (Petromyzon marinus; an invasive fish in the Great Lakes Basin, North America) upstream passage probability declined from 0.73 to 0.03 as flow conditions became increasingly turbulent, while declines in white sucker (Catostomus commersonii, a native fish in the region) upstream passage probability were less substantial (0.53 to 0.44). Deploying a sea lamprey trap in the fishway did not effectively reduce sea lamprey upstream passage probability, though capture rate increased during trials with cooler water temperature and low total kinetic energy. Bifurcated fishways that maintain low turbulent flow in the entrapment route and high turbulent flow in the upstream passage route could increase the effectiveness of trapping sea lamprey in fishways as a means to advance selective passage goals.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Barriers are an effective mechanism for managing invasive species, such as sea lamprey in the Laurentian Great Lakes but are detrimental because they limit the migration of desirable, native species. ...Fish passage technologies that selectively pass desirable species while blocking undesirable species are needed. Optical sorting tools, combined with newly developed computer learning algorithms, could be used to identify invasive species from high-resolution imagery and potentially isolate them from an assortment of the Great Lakes fishes. Many existing barriers lack fishways, and optical sorting may require fish to be dewatered for image capture. The Archimedes screw, a device originating from 234 BCE, offers the potential to continuously lift fish and water over low-head barriers or into an optical sorting device. To test the efficacy of an Archimedes screw and fish lifting to capture and pass Great Lakes fishes, we built a field-scale prototype and installed it at the Cheboygan Dam, Michigan in the USA in 2021. The fish lift safely transported 704 fish (688 of which were suckers (Catostomidae)) in 11 days. The passage of the suckers through the fish lift increased with the water temperature and attraction flow. There were no observed injuries in the transported fish or mortalities in a subset of suckers held post-transport.
Hydrophobic and hydrophilic silver-functionalized SBA-15 silica nanocomposites were prepared via direct synthesis using the so-called BOTTOM-UP approach to nanotechnology. This process enables ...silica-based nanocomposites with a controlled metal content to be fabricated. XRD, XPS, Raman, SEM-EDX and TEM methods were used to describe the physicochemical properties of these systems. The surface atomic content of silver (XPS) was estimated at approximately 0.03 at.% and 0.04 at.% compared to the bulk signal (SEM-EDX), which was determined to be about 0.33 at.% and 0.48 at.%, respectively for the non-silylated and silylated systems. The XPS studies that were carried out for these two structures revealed the presence of elemental and/or oxidized silver on the surfaces. However, in the more volumetric XRD studies, there was no clear signal that corresponded to this metal, which suggests the presence of an ionic form of silver. Calcination was used to obtain the silver-decorated porous silica ceramic composites, for which the calcination temperature was determined from TGA/DTG studies. The calcination resulted in the compensation of the surface and bulk atomic content of silver at approximately 0.1 at.% (on both the surface and the bulk). The wettability measurements classified silylated specimens as well as silylated and calcined systems as being hydrophilic and hydrophobic, respectively. Low-angle diffraction confirmed the mesoporous character of the silica with hexagonal pore channels regardless of the degree of functionalization or calcination. The Raman data illustrated the impact of the silver on the propyl-carbonate chains and silica structure. Finally, the most vigorous bactericidal activity was found against Staphylococcus aureus and Escherichia coli for a hydrophilic system with a low silver content and a calcined sample with a slightly higher silver concentration.
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•Development of the hydrophobic and hydrophilic materials with homogeneously distributed metal (M = Ag+) ions.•Impact of mesopores functionalization on the structure and biological effect.•Impact of the temperature on the structural and biologic features of the mesopores systems.
•Examine the performance of three bubble curtains to inhibit common carp movement.•Bubble curtains reduced carp passage by 75–85%.•Bubble curtains generated acoustic fields above carp hearing ...thresholds.•Avoidance behavior influenced by sound and fluid motion rather than visual cues.•Bubble curtains may be a viable and inexpensive carp deterrence system.
Although bubble curtains have been proposed many times as practical and inexpensive solutions to hinder the movement of invasive fish, few studies have examined why or how they might work. By understanding how bubble curtains influence fish behavior, management tools could be developed to control movement of invasive fish. In this study, the common carp (Cyprinus carpio L.) was used to examine the performance of three different bubble curtains (fine-, graded-, and coarse-bubble) and acoustically enhanced systems in an indoor channel. Trials revealed that the graded- and coarse-bubble systems reduced common carp passage across the curtain by 75–85% in both up- and down-stream directions. Concurrent acoustic field measurements revealed that these bubble curtains generated sound near 200Hz at approximately 130dB (ref 1μPa), well above the common carp hearing threshold. Further testing with speaker arrays and lighting indicated that carp avoidance of the bubble curtain involved responses to sound and fluid motion rather than visual cues. Although field tests are warranted, our results suggest that bubble curtains may be a viable and inexpensive deterrence system to limit common carp movement.
Abstract Transected spinal cord regeneration is a main challenge of regenerative medicine. The mainstream of research is focused on the promotion of spinal axons growth, which is strongly inhibited ...in mammals. Assuming that the inhibition of the axonal growth may be ever overcome, the complexity of neural recconections may be the second serious stand to overcome. Peripheral nerve axons regeneration seem to form a random pattern of their targets reconnections. The hypothesis is that due to the laws of entropy or irreversible information loss the full spinal cord restoration after the transection is not possible. The hypothesis is discussed based on several assumptions. Simplyfying the dissertation spinal cord is represented by 2 millions of pyramidal axons. After the transection each of theese axons has to make a growth and reconnect with exactly matching targets below the transection, in the same number. Axons are guided by neurotrophic factors and afterwards reconnected with neuroplasticity mechanisms. Assuming random reconnections, there are 2000000! permutations (10^(10^7.069426636687223), therefore the chance of ideally random but correct reconnection of pyramidal axons with adequate targets is 1/2000000!. Apart from pyramidal axons, there are other axons, like extrapyramidal, sensory and associative. Empirical data and analysis of neurotrophic factors and organogenesis mechanisms may seem to slightly contradict the hypothesis, but strictly adhering to the second law of thermodynamics and entropy laws the full restoration of the transected cord may never be possible.
This study investigated the leap characteristics of rainbow trout (also known as steelhead) (Oncorhynchus mykiss) present in the Laurentian Great Lakes. To aid in the collection and annotation of ...leaps, a custom web application was developed and through the labeling of key markers, the launch speed, launch angle, and length of the fish were calculated. Data collection took place during migratory runs in the spring of 2022 and 2023 that resulted in 173 total leaps annotated with mean launch angles of 58.73 and 68.2 degrees, in 2022 and 2023, respectively. The mean launch speed normalized by body length was consistent across years at 8.6 body lengths per second. The integration of leaping data with computational fluid dynamics simulations revealed steelhead launch angle aligns closely with the water velocity direction as the velocity magnitude increases. Applications of this study include hazard analyses for unintended escapement and informed design of intelligent migratory barriers such as those to be developed at FishPass, an instream research facility under design for the Boardman (Ottaway) River in Traverse City, MI, USA.
In this paper, we address a problem of vision-based 3D robotic navigation using deep reinforcement learning for an Autonomous Underwater Vehicle (AUV). Our research offers conclusions from the ...experimental study based on one of the RoboSub 2018 competition tasks. However, it can be generalized to any navigation task consisting of movement from a starting point to the front of the next station. The presented reinforcement learning-based model predicts the robot’s steering settings using the data acquired from the robot’s sensors. Its Vision Module may be based on a built-in convolutional network or a pre-trained TinyYOLO network so that a comparison of various levels of features’ complexity is possible. To enable evaluation of the proposed solution, we prepared a test environment imitating the real conditions. It provides the ability to steer the agent simulating the AUV and calculate values of rewards, used for training the model by evaluating its decisions. We study the solution in terms of the reward function form, the model’s hyperparameters and the exploited camera images processing method, and provide an analysis of the correctness and speed of the model’s functioning. As a result, we obtain a valid model able to steer the robot from the starting point to the destination based on visual cues and inputs from other sensors.
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•Examining vision-based, deep reinforcement learning approach for Autonomous Underwater Vehicle (AUV) navigation.•Proposing and analyzing reward function components relevant to a 3D navigation problem.•Researching various image processing methods and visual features’ complexity used in the AUV controller.•Evaluating the solution in a realistic simulation environment, regarding its success rate, achieved reward value and prediction speed.
Harmonic Phasor Estimation With Flat-Top FIR Filter Duda, Krzysztof; Zielinski, Tomasz P.; Bien, Andrzej ...
IEEE transactions on instrumentation and measurement,
05/2020, Letnik:
69, Številka:
5
Journal Article
Recenzirano
The IEEE Std C37.118.1(a) describes synchrophasor measurement by a phasor measurement unit (PMU) for the system fundamental frequency. Harmonic synchrophasor, i.e., synchrophasor measured for ...harmonic frequencies, is not considered in the standard. Harmonic synchrophasor is useful for harmonic state estimation, power quality (PQ) monitoring, and harmonic power flow analysis. In this paper, we investigate the usability of the standard basic synchrophasor estimation model for the estimation of harmonic phasor (HP) up to the 50th harmonic as advised by the IEC Std 61000-4-7. For the estimation of HPs, an application of the flat-top (FT) finite-impulse-response (FIR) filter is proposed. Results for the maximally flat differentiator and the interpolated discrete Fourier transform (DFT) are also presented, confirming the superior performance of the proposed FT filter approach. HP estimation is verified with extended tests of the IEEE Std C37.118.1(a), including steady-state and dynamic conditions with additive 60-dB noise.
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