Hasil untuk "Aquaculture. Fisheries. Angling"

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arXiv Open Access 2026
Particle acceleration and pitch-angle evolution in relativistic turbulence

Daniel Humphrey, Cristian Vega, Stanislav Boldyrev et al.

Synchrotron radiation detected from relativistic astrophysical objects such as pulsar-wind nebulae and {jets from active galactic nuclei} depends on the magnetic fields and the distribution functions of energetic electrons in these systems. Relativistic magnetically dominated turbulence has been recognized as an efficient mechanism for structure formation and non-thermal particle acceleration in these environments. Recent numerical simulations of relativistic turbulence have provided insights into the energy distribution functions of accelerated electrons. Much less is currently understood about their {pitch angle distributions}, which are crucial for accurately interpreting the spectra of synchrotron radiation. {We perform a detailed case study of} the pitch angle distributions formed during the process of turbulent acceleration {for $B_0/δB_0 = 10$ and $\tildeσ_0 \sim 40$, where $B_0$ is the uniform component of the magnetic field, $δB_0$ is the fluctuating component, and $\tildeσ_0$ is the plasma magnetization based on the magnetic fluctuations. We find that even minimal numerical noise can cause substantial pitch angle scattering, but we demonstrate techniques for overcoming the numerical challenges associated with the evolution of very small pitch angles. Our numerical results are consistent with the phenomenological model found in \cite[][]{vega2024b,vega2025}.}

en astro-ph.GA, physics.plasm-ph
CrossRef Open Access 2025
Adaptive Reproductive Strategies in Schizothoracine Fishes: Dual Spawning Phases and Environmental Synchronization in Himalayan Ecosystems

Syed Talia Mushtaq

ABSTRACT Schizothoracine fishes, endemic to the Himalayan region, exhibit remarkable adaptive reproductive strategies in response to their challenging high‐altitude aquatic environments. This review synthesizes current knowledge on the dual spawning phases and environmental synchronization observed in these species, with a focus on the genus Schizothorax . These fishes demonstrate a unique ability to spawn twice annually, with distinct breeding periods in summer (June–October) and winter (January–March). Dual spawning phases allow Schizothoracine fishes to optimize reproductive output by synchronizing hatching and larval emergence with periods of high food availability and favourable temperatures, thereby increasing offspring survival (Bromage et al. 1993; Tao et al. 2018). This reproductive plasticity is closely synchronized with environmental cues such as water temperature, discharge, and photoperiod, allowing for optimized breeding cycles in dynamic ecosystems. Notably, spawning periods may vary among populations of the same species based on local ecological conditions and elevational gradients. The review explores the adaptive significance of these strategies, including increased reproductive success and enhanced population resilience. In addition, it examines the implications of these adaptations for conservation efforts in the face of climate change and anthropogenic pressures in the Himalayan region.

DOAJ Open Access 2025
Factors influencing land rental market participation: a case study in Northern Ireland

Adewale Henry Adenuga, Claire Jack

Agricultural land mobility through an efficient land rental market has been shown to contribute to the productive and sustainable utilisation of land, by facilitating the transfer of land from less productive farmers to more productive farmers. However, this is not the case in Northern Ireland where the sale of agricultural land is limited with a constrained tenanted sector. The objective of this study is to analyse the factors influencing participation in the land rental market in Northern Ireland. To achieve our objective, data from 1466 farmland owners was analysed using principal component analysis (PCA) and multinomial logistic regression model. The results show that land rental market participation is impacted by motivational and socioeconomic factors. The study recommends the development of schemes that support the early and comfortable retirement of older farmers to increase the access of young farmers to land and improve the land rental market.

Aquaculture. Fisheries. Angling, Forestry
DOAJ Open Access 2025
Cholesterol Accumulation Caused Oxidative Stress Associated With Impaired Antioxidant Capability and Mitochondrial Function in the Liver of Nile Tilapia

Zhixiao Liu, Yi Xiao, Jiaying Xie et al.

In mammals, cholesterol accumulation in tissues often results in health damage, such as oxidative stress. In contrast, the adverse effects of cholesterol accumulation on the physiological health of fish remain largely unexplored. The present study investigated the impacts of cholesterol accumulation on oxidative stress and the potential mechanisms involved in Nile tilapia (Oreochromis niloticus). Thus, Nile tilapia were fed either a control diet (C) or a high-cholesterol (1.6%, HC) diet for 8 weeks. The viscero-somatic (VSIs) and hepatosomatic indices (HSIs) were increased significantly in fish fed the HC diet and, in accordance, HC intake caused the accumulation of cholesterol in the liver, intestine, head kidney, and spleen. Intake of the HC diet, affected oxidative stress as evidenced by elevated malondialdehyde (MDA) levels in the liver and head kidney and reduced catalase (CAT) activities in the liver and spleen, while SOD activities were increased in the spleen and intestine. Moreover, cholesterol accumulation induced endoplasmic reticulum (ER) stress, inflammation, and apoptosis in the liver and head kidney, as evidenced by increased expression levels of key genes. Metabolome analysis indicated that metabolite levels in tilapia fed the HC diet were primarily enriched in glutathione metabolism and the tricarboxylic acid cycle (TCA), with significantly reduced levels of glutamine, glutamate, glycine, citrate, isocitrate, aconitate, malate, and oxalate. In addition, transmission electron microscopy (TEM) analysis showed accumulation of lipid droplets and distinct alterations in the morphology of mitochondria within hepatocytes of tilapia fed HC. Moreover, significantly increased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were found in fish fed the HC diet. Overall, the data suggested that HC intake induced oxidative stress, which might be associated with impaired antioxidant capability and mitochondrial function, as mitochondria are the primary site of producing cellular reactive oxygen species (ROS). The present study is the first to report the impacts of cholesterol accumulation on oxidative stress and health damage in fish, and suggested targeted cholesterol-lowering interventions as a promising therapeutic strategy for addressing health issues in aquatic animals.

Aquaculture. Fisheries. Angling
arXiv Open Access 2025
Full-Angle Ray Antenna Array and Omnicell Wireless Communication System

Xuancheng Zhu, Zhiwen Zhou, Yong Zeng

Ray antenna array (RAA) was recently proposed as a novel multi-antenna architecture that arranges multiple massive cheap antenna elements into simple uniform linear arrays (sULAs) with different orientations. Compared with traditional architectures like hybrid analog/digital beamforming with uniform linear array (ULA) and uniform circular array (UCA), RAA has several promising advantages such as significantly reduced hardware cost, higher beamforming gains and the ability of providing uniform angular resolution for all directions. In this paper, we propose a full-angle RAA architecture and an innovative omnicell wireless communication paradigm enabled by full-angle RAA. The proposed full-angle RAA expands RAA's orientation angle to the full angle domain, such that the RAA's advantages can be exploited to all directions. This further enables the new concept of omnicell wireless communication system, with the base station equipped by full-angle RAA and deployed at the center of each cell. Compared to the conventional cell sectoring wireless communication system, the proposed omnicell system is expected to not only significantly reduce the inter-user interference, but also improve the cost efficiency. Extensive analytical and numerical results are provided to compare those key performance indicators such as the spatial resolution and the communication rate of the proposed full-angle RAA based omnicell wireless communication system against the conventional ULA/UCA-based cell sectoring systems.

en eess.SP
DOAJ Open Access 2024
Distribution and growth of Nga Myin Yinn, Silonia silondia (Actinopterygii: Siluriformes: Schilbeidae), in the Ayeyarwady River, Myanmar

Aye Aye Min, Toe Toe Soe, Thida Lay Thwe et al.

The silond catfish, Silonia silondia (Hamilton, 1822), known locally as Nga Myin Yinn, is rare in Myanmar fish markets and can fetch a high price. Efforts are being made to increase the production for domestic demand. We examined the distribution and growth of S. silondia based on catches in the Ayeyarwady River and growth records in fish farms near the river. The smaller fish were observed downstream near their nursery and the medium fish were around 1 m total length (TL) were often widespread, whereas the larger fish preferred upstream locations. Estimating the individual age from poorly defined periodic rings on the surface of otolith sections was difficult, but their microchemistry may reflect a shared nursery environment and subsequent migration throughout the entire river region. The growth curve estimates in the farmed population revealed a mean TL of 60 cm at four years, indicating that farmed fish were smaller than commercially captured wild fish. This is one of the first comprehensive studies of the river region, but more detailed surveys are needed to manage the fish resource sustainably.

Aquaculture. Fisheries. Angling
arXiv Open Access 2024
On point-ahead angle control strategies for TianQin

Dezhi Wang, Xuefeng Zhang, Hui-Zong Duan

Pointing-related displacement noises are crucial in space-based gravitational wave detectors, where point-ahead angle control of transmitted laser beams may contribute significantly. For TianQin that features a geocentric concept, the circular high orbit design with a nearly fixed constellation plane gives rise to small variations of the point-ahead angles within $\pm 25$ nrad in-plane and $\pm 10$ nrad off-plane, in addition to a static bias of 23 $μ$rad predominantly within the constellation plane. Accordingly, TianQin may adopt fixed-value compensation for the point-ahead angles and absorb the small and slow variations into the pointing biases. To assess the in-principle feasibility, the far-field tilt-to-length (TTL) coupling effect is discussed, and preliminary requirements on far-field wavefront quality are derived, which have taken into account of TTL noise subtraction capability in post processing. The proposed strategy has benefits in simplifying the interferometry design, payload operation, and TTL noise mitigation for TianQin.

en gr-qc, astro-ph.IM
arXiv Open Access 2024
Role of the constriction angle on the clogging by bridging of suspensions of particles

Nathan Vani, Sacha Escudier, Deok-Hoon Jeong et al.

Confined flows of particles can lead to clogging, and therefore failure, of various fluidic systems across many applications. As a result, design guidelines need to be developed to ensure that clogging is prevented or at least delayed. In this Letter, we investigate the influence of the angle of reduction in the cross-section of the channel on the bridging of semi-dilute and dense non-Brownian suspensions of spherical particles. We observe a decrease of the clogging probability with the reduction of the constriction angle. This effect is more pronounced for dense suspensions close to the maximum packing fraction where particles are in contact in contrast to semi-dilute suspensions. We rationalize this difference in terms of arch selection. We describe the role of the constriction angle and the flow profile, providing insights into the distinct behavior of semi-dilute and dense suspensions.

en cond-mat.soft
DOAJ Open Access 2023
Effects of copper exposure and recovery in juvenile yellowtail kingfish (Seriola lalandi): Histological, physiological and molecular responses

Zhixin Jin, Yongjiang Xu, Heting Zhou et al.

This study investigated the physiological responses to copper toxicity in liver and gill of juvenile yellowtail kingfish by exposing to 0 (control), 0.0672, 0.12, 0.214, 0.384, 0.672, 1.20, or 2.14 mg/L copper sulfate for 7 days and then recovered for 14 days. The histopathology, enzyme activities and differential gene expression were detected. The results indicate the safe concentration value of copper for juvenile yellowtail kingfish is 0.083 mg/L. Copper exposure caused structural damage to gill and liver, and could be disappeared or restored after the recovery period. Copper exposure enhanced the Cu,Zn superoxide dismutase (Cu/Zn-SOD) and glutathione peroxidase (GSH-Px) activities and the malondialdehyde (MDA) level in liver. However, with increasing copper concentrations, liver aspartate transaminase (AST) and gill Na+/K+-ATPase activities were at first enhanced and then inhibited. Serum lysozyme (LZM) and Cu/Zn-SOD activities were enhanced at low copper concentrations but inhibited at high concentrations, and the activities of alanine transaminase (ALT) and AST significantly increased at greater copper concentrations. After the recovery period, only liver Cu/Zn-SOD activity returned to control level. In contrast, liver GSH-Px activity and MDA levels and gill Na+/K+-ATPase activity, serum LZM and AST activities remained significantly higher than control, but liver AST activity, serum ALT, and Cu/Zn-SOD activities were significantly lower than control. We constructed the gene regulatory networks of molecular pathways in liver and gill in response to copper exposure. The DEGs were enriched mainly in the pathway of lipid metabolism in liver and pathway of oxidative phosphorylation in gill, indicating these respective pathways are involved in the response to copper stress in this species. The present results elucidate some histological, physiological, and molecular mechanisms underlying copper-exposure stresses in yellowtail kingfish, which could help guide the safe utilization of copper sulfate in disease control of farmed individuals.

Aquaculture. Fisheries. Angling
arXiv Open Access 2023
A Robust Hybrid Observer for Side-slip Angle Estimation

Agapius Bou Ghosn, Marcus Nolte, Philip Polack et al.

For autonomous driving or advanced driving assistance, it is key to monitor the vehicle dynamics behavior. Accurate models of this behavior include acceleration, but also the side-slip angle, that eventually results from the complex interaction between the tires and the road. Though it is an essential quantity (e.g. for stability assessment), as opposed to accelerations, it is not measurable through conventional off-the-shelf sensors. Therefore, accurate side-slip angle observers are necessary for the proper planning and control of vehicles. In this paper, we introduce a novel approach that combines model-based side-slip angle estimation with neural networks. We apply our approach to real vehicle data. We prove that the proposed method is able to outperform state-of-the-art methods for normal driving maneuvers, and for near-limits maneuvers where providing accurate estimations becomes challenging.

en cs.RO
DOAJ Open Access 2022
Swimbladder non-inflation and its influence on larviculture of mandarin fish (Siniperca chuatsi)

YuHui He, Xu-Fang Liang, WenJie Guo et al.

Low occurrence of swimbladder inflation often leads to vertebral skeletal malformations and poor swimming ability, which exert numerous effects on growth, feeding, buoyancy regulation and survival rate of fish larvae. In the present study, 713 mandarin fish (Siniperca chuatsi) larvae samples ranging from 5 to 11 days post hatch (DPH) were collected to detect the rate of swimbladder inflation and calculate the body density of each sample. Swimbladder inflated fish larvae were increased with the development of DPH except 7 DPH, with 86.21% in 11 DPH whereas 27.59% in 5 DPH. Our results indicate that 5–11 DPH is the main stage for swimbladder inflation in mandarin fish larvae, following the onset of exogenous feeding. The body density of swimbladder inflated (SBI) fish larvae (0.983 ± 0.016 g/cm3) was lower than the swimbladder non-inflated (SBN) ones (1.023 ± 0.018 g/cm3), while SBI fish larvae were significant heavier (p < 0.05) than SBN group. These findings suggest that swimbladder non-inflation could significantly influenced the neutrally buoyancy maintained and live bait predation in mandarin fish. The research will contribute to understanding the influence of initial swimbladder inflation on larviculture of mandarin fish.

Aquaculture. Fisheries. Angling
DOAJ Open Access 2022
Oxidative stress responses of the crayfish Procambrus clarkii to Spiroplasma eriocheiris challenge

Zhengfeng Ding

As a virulent pathogen, Spiroplasma eriocheiris influences most crustaceans, including the freshwater crayfish Procambrus clarkii. The antioxidant enzymes related to oxidative stress during the pathogenesis of S. eriocheiris in the primary target tissues of hepatopancreas and gills from P. clarkii were analyzed at various time intervals post-infection. H.E histopathology and in situ hybridization assays confirmed the S. eriocheiris infection and detected typical histological changes. Compared with the control group, catalase (CAT) activities in both tissues reduced significantly at the early time of S. eriocheiris challenge (P < 0.05), but recovered gradually at the late stage while still lower than the control group in the hepatopancreas (P < 0.05). A similar tendency was observed in the change of superoxide dismutase (SOD) activities. Acid phosphatase (ACP) and alkaline phosphatase (AKP) activities increased considerably and achieved peak values at 7 days post-infection (dpi) in the hepatopancreas and 5 dpi in the gills, but decreased significantly later till 12 dpi in both tissues (P < 0.05). Peroxidase (POD) activities and malondialdehyde (MDA) contents increased dramatically since the first day and kept a high level during the challenge course. The activities of antioxidant enzymes were generally higher in the hepatopancreas than in the gills. These results suggested that S. eriocheiris affected the antioxidative situation and caused oxidative stress and tissue damage by confusing antioxidant enzymes in P. clarkii.

Aquaculture. Fisheries. Angling
arXiv Open Access 2022
Electronic anisotropy in magic-angle twisted trilayer graphene

Naiyuan J. Zhang, Yibang Wang, Kenji Watanabe et al.

Due to its potential connection with nematicity, electronic anisotropy has been the subject of intense research effort on a wide variety of material platforms. The emergence of spatial anisotropy not only offers a characterization of material properties of metallic phases, which cannot be accessed via conventional transport techniques, but it also provides a unique window into the interplay between Coulomb interaction and broken symmetry underlying the electronic order. In this work, we utilize a new scheme of angle-resolved transport measurement (ARTM) to characterize electron anisotropy in magic-angle twisted trilayer graphene. By analyzing the dependence of spatial anisotropy on moiré band filling, temperature and twist angle, we establish the first experimental link between electron anisotropy and the cascade phenomenon, where Coulomb interaction drives a number of isospin transitions near commensurate band fillings. Furthermore, we report the coexistence between electron anisotropy and a novel electronic order that breaks both parity and time reversal symmetry. Combined, the link between electron anisotropy, cascade phenomenon and PT-symmetry breaking sheds new light onto the nature of electronic order in magic-angle graphene moiré systems.

en cond-mat.mes-hall, cond-mat.str-el
CrossRef Open Access 2021
Quantitative estimates of freshwater fish stocking practices by recreational angling clubs in France

Julien Cucherousset, Rémy Lassus, Carsten Riepe et al.

AbstractAlthough freshwater fish stocking is widely used by managers, quantitative assessments of stocking practices are lacking in many countries. The general objective of the present study was to determine the quantity and characteristics of fish stocking in metropolitan France. Using a survey‐based approach, stocking practices for 2013 by recreational angling clubs in France were quantified, which represented the bulk of fish stocking undertaken in that year. Stocking was found to be practiced by 88.6% of angling clubs in France, representing, on average, 65% of their annual budget. Overall, 22 species were stocked, including 13 native and nine non‐native species, with strong variations among species in terms of life stages and body sizes used for stocking. Using Bayesian modelling, a total biomass of 2.029 t, representing approximately 90 million fishes, was estimated to be stocked in France in 2013. In terms of biomass, the most widely stocked species were rainbow troutOncorhynchus mykiss(Walbaum), brown troutSalmo truttaL., roachRutilus rutilus(L.), common carpCyprinus carpioL. and northern pikeEsox luciusL. A stocking volume of approximately 60 fishes or 1.5 kg of fish biomass per angler per year seems commonplace in industrialised countries for which data are available.

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