Hasil untuk "Aquaculture. Fisheries. Angling"

Kai Yan, Huirong Yan, Parth Pavaskar et al.

Cosmic-ray pitch-angle transport in magnetohydrodynamic (MHD) turbulence is governed by the interplay between magnetic mirroring and gyroresonant scattering. We develop a guiding-center (GC) Langevin model with explicit mirror drift and gyroresonant diffusion to describe the pitch angle evolution. This model accurately captures our test-particle simulation results in three-dimensional MHD turbulence, driven both solenoidally and compressively. We find that magnetic mirroring can drive anomalous pitch-angle diffusion at large pitch angles (including $90^\circ$) with non-Markovian memory effects, which arises from trapping of particles in magnetic wells. Gyroresonant scattering controls the escape rate from these wells. Across $M_{\rm A}$, large-pitch-angle particles are jointly regulated by mirror trapping and gyroresonant escape, exhibiting a transition from anomalous to normal diffusive pitch-angle transport as scattering strengthens, whereas small-pitch-angle particles remain gyroresonance-dominated and diffusive throughout. The pitch angle transport is found to be dominated by the compressible perturbations with marginal influence from Alfvén modes. In compressible turbulence with realistic damping accounted for, transit time damping (TTD) treatment fully recovers mirror interactions.

Treer Tomislav

The number of artisanal fishers, and consequently their catch, in the Sava River has declined significantly over the past two decades. The average weight of some species has also changed significantly. Therefore, the aim of this paper is to investigate possible changes in the biomass proportion in the catch of the most important taxa during this period. Most of the investigated species showed considerable variation in catch from year to year, but without a clear trend (P > 0.05). The largest fluctuations, with a coefficient of variation (CV) over 90%, were found in Acipenser ruthenus, Cyprinus carpio, Leuciscus aspius and allochthonous species. Esox lucius, Leuciscus idus, Silurus glanis and Sander lucioperca had CVs between 41% and 73%. The smallest variations in the proportion of catch were recorded for Abramis brama and other autochthonous species (the most abundant being Rutilus virgo), with CVs of 37.77% and 33.43%, respectively. These two taxa also showed significant opposite trends (R² = 0.34; P < 0.01) and had a combined average biomass proportion of 67.03%.

Germain Maurus, Joan Tang Xiao Joe, Quốc Hùng Phạm et al.

Abstract This study evaluated the benefits of a commercial probiotic, Aqua Fortuna probiotic (AFPB), containing multiple bacterial strains isolated from fish gut microbiota, on the physiological performance of white‐leg shrimp (Litopenaeus vannamei). Juvenile shrimp were fed varying doses of AFPB (0.5%, 1%, 2%, and 5%) during their maturation period, and their growth indices, including weight, growth rate, feed conversion ratio, and survival rate, were measured biweekly. In addition, gene expression levels of growth factors (IGF1, IGFBP, VEGF1–3) and immune‐related markers (antimicrobial peptides: penaeidin‐3a, crustin, lysozyme; pattern recognition receptors: β‐1,3‐glucan binding protein, lipopolysaccharide, and β‐glucan binding protein; detoxification enzymes: SOD, prophenoloxidase, hemocyanin) were analyzed in digestive tissues via qPCR on week 8. Furthermore, L. vannamei was challenged with Vibrio parahaemolyticus, and post‐challenge survival rates were monitored. The results revealed that AFPB supplementation significantly enhanced the growth performance of L. vannamei. Notably, 1% of AFPB yielded the most significant improvements in the final weights, specific growth rates, and better survival rates. During the lethal challenge with V. parahaemolyticus, groups treated with 5% and 2% AFPB showed higher survival rates at 4 and 8 weeks, respectively. Gene expression analyses showed that 1% AFPB upregulated penaeidin‐3a, crustin, lysozyme, prophenoloxidase, superoxide dismutase, and β‐1, 3 glucans binding protein in digestive tissues, whereas 2% AFPB additionally upregulated immune genes like prophenoloxidase and lysozyme. Our findings highlight the role of shrimp microbiota in promoting growth and enhancing disease resistance, providing robust evidence for the use of probiotics as a strategy to improve shrimp cultivation productivity.

Nurul Mutmainnah, Lidya Lidya, Zulfiani Zulfiani et al.

Freshwater crayfish (Cherax quadricarinatus) is a valuable aquaculture commodity with relatively easy cultivation. However, low larval survival during early developmental stages remains a major challenge in its farming. This study aims to evaluate the effects of dissolved glucose and amino acid combinations on growth characteristics, molting frequency, and survival rate. The research was conducted in the Greenhouse of the Faculty of Agriculture, Animal Husbandry, and Fisheries, Universitas Muhammadiyah Parepare, using hatchery-produced crayfish larvae. Four dosage combinations were tested: A) 100 ppm glucose + 250 ppm amino acids, B) 150 ppm glucose + 200 ppm amino acids, C) 200 ppm glucose + 150 ppm amino acids, and D) 250 ppm glucose + 100 ppm amino acids, each replicated three times. The results showed that glucose and amino acid combinations significantly affected crayfish length growth. The highest absolute length growth was observed in the 250 ppm glucose + 100 ppm amino acid group. Meanwhile, the 150 ppm glucose + 200 ppm amino acid combination showed the best performance in molting frequency, number of molting crayfish, survival rate, and percentage of surviving crayfish. The optimal treatment for supporting freshwater crayfish growth and development was the 150 ppm glucose + 200 ppm amino acid combination. Keywords: Cherax quadricarinatus Glucose amino acids growth characteristics survival rate molting

Jason Behrstock, Recep Altar Ciceksiz, Victor Falgas-Ravry

We consider the random right-angled Coxeter group $W_Γ$ whose presentation graph $Γ\sim \mathcal{G}_{n,p}$ is an Erd{\H o}s--Rényi random graph on $n$ vertices with edge probability $p=p(n)$. We establish that $p=1/\sqrt{n}$ is a threshold for relative hyperbolicity of the random group $W_Γ$. As a key step in the proof, we determine the minimal number of pairs of generators that must commute in a right-angled Coxeter group which is not relatively hyperbolic, a result which is of independent interest. We also show that there is an interval of edge probabilities of width $Ω(1/\sqrt{n})$ in which the random right-angled Coxeter group has precisely cubic divergence. This interval is between the thresholds for relative hyperbolicity (whence exponential divergence) and quadratic divergence. Moreover, a simple random walk on any Cayley graph of the random right-angled Coxeter group for $p$ in this interval satisfies a central limit theorem.

Wei Li, Huanrong He, Shiyu Li et al.

The aim of the present study was to investigate the effects of dietary Lactobacillus reuteri on the antimicrobial activity, antioxidant capacity, immune response, and disease resistance against Streptococcus agalactiae of the Nile tilapia (Oreochromis niloticus). The results of in vitro antibacterial assay demonstrated that L. reuteri had antibacterial effects against the main pathogenic bacteria of tilapia, S. agalactiae and Aeromonas hydrophila. A feeding trial was next conducted, fingerling tilapia were fed with basal diet (control [CT]) supplemented with L. reuteri at concentrations of 109 (R9), 1010 (R10), and 1011 (R11) colony-forming units /kg for 56 days. Dietary L. reuteri significantly decreased blood glucose (p < 0.05) and significantly increased LZM activity of serum in R10 and R11 groups as compared to the CT group. In addition, the activity of glutathione peroxidase was decreased in R11 group, the level of malondialdehyde was decreased and the level of glutathione was increased in R10 and R11 group, and the level of total antioxidant capacity was increased in R9, R10 and R11 groups (p < 0.05). As compared to the CT group, the transcriptional level of TGF-β was significantly increased in liver samples of the R10 and R11 groups (p < 0.05). In the intestinal mucosa, mRNA expression of TGF-β was significantly upregulated, while that of IL-1β was significantly downregulated in the R10 and R11 groups (p < 0.05). Moreover, the survival rate was significantly higher in tilapia fed L. reuteri than the CT group after challenge with S. agalactiae. The relative percent survival of the R10 and R11 groups compared to CT group was 35.30%, and the RPS of group R9 compared to group CT was 23.53%. These results demonstrate that dietary L. reuteri enhanced antioxidant capacity, regulated immune-related genes and improved resistance against S. agalactiae in tilapia.

Suhyeok Kim, Jaebeom Shin, Hyunwoon Lim et al.

This study was conducted to investigate the effects of feeding Artemia nauplii enriched with poly-β-hydroxybutyrate (PHB) on Pacific white shrimp (Penaeus vannamei) post-larvae. A total 900 shrimp (initial average body weight: 2.50 ± 0.01 mg) were randomly distributed into 9 acrylic tanks (96 L) in triplicate groups. The Artemia reared in 0%, 0.25% and 0.50% PHB dissolved water (designated as Con, PHB25 and PHB50, respectively) were fed to the shrimp post-larvae for 14 days. The growth performance of shrimp was significantly higher in PHB25 and PHB50 groups than those in Con group. Survival was not significantly different among all the groups. Relative gene expressions of trypsin and amylase were significantly upregulated in PHB25 group than those of Con group. Relative gene expression of chymotrypsin was significantly upregulated in PHB25 and PHB50 groups compared to Con group. Relative gene expression of insulin-like growth factor-I was significantly upregulated in PHB25 group than in Con group. Relative gene expression of insulin-like growth factor-binding protein was significantly upregulated in both PHB25 and PHB50 groups than that of Con group. Relative expression of prophenoloxidase gene was significantly upregulated in PHB25 and PHB50 groups as compared to Con group. Relative expression of penaeidin-3a gene was significantly upregulated in PHB50 group as compared to Con group. This study demonstrated that PHB, as a functional nutritional enrichment for Artemia, improves the growth, digestibility and immunity of shrimp post-larvae.

Bruna Tomazetti Michelotti, Marco Shizuo Owatari, Caio Magnotti et al.

This study evaluated the effects of dietary supplementation with citral on growth performance and intestinal parameters, and specific activity of the digestive enzymes of Sardinella brasiliensis.  240 juvenile S. brasiliensis were randomly distributed in a recirculating aquaculture system (RAS) composed of 12 circular tanks of 150 L (n = 20 per tank). A diet without citral addition (control) and three diets containing different levels of citral inclusion (0.5, 1.0 and 2.0 mL kg*feed–1) were used in the fish feeding management during 20 days. The indexes of zootechnical performance, survival, weight gain, specific growth rate, feed conversion and condition factor of the fish were verified, as well as digestive enzymes and histological analysis. A significant positive relationship was found between citral supplementation and fish survival. In the specific activity of digestive enzymes, dietary citral supplementation at 2.0 mL* kg feed–1 increased lipase and amylase activity. Citral supplementation positively influenced the number of villi and intestinal crypt depth. Furthermore, the inclusion of citral at 0.5 mL kg*feed–1 increased the intestine diameter of the fish. The results of the experiment suggest that the addition of citral as an additive in the diet of S. brasiliensis improved the survival of fish.

Peter Semrl

Let $n$ be a positive integer and $H$ a Hilbert space. The description of the general form of bijective maps on the set of $n$-dimensional subspaces of $H$ preserving the maximal principal angle has been obtained recently. This is a generalization of Wigner's unitary-antiunitary theorem. In this paper we will obtain another extension of Wigner's theorem in which the maximal principal angle is replaced by the minimal one. Moreover, in this case we do not need the bijectivity assumption.

Jianzhu Huai, Yuan Zhuang, Yuxin Shao et al.

Wide-angle cameras are widely used in photogrammetry and autonomous systems which rely on the accurate metric measurements derived from images. To find the geometric relationship between incoming rays and image pixels, geometric camera calibration (GCC) has been actively developed. Aiming to provide practical calibration guidelines, this work surveys the existing GCC tools and evaluates the representative ones for wide-angle cameras. The survey covers camera models, calibration targets, and algorithms used in these tools, highlighting their properties and the trends in GCC development. The evaluation compares six target-based GCC tools, namely, BabelCalib, Basalt, Camodocal, Kalibr, the MATLAB calibrator, and the OpenCV-based ROS calibrator, with simulated and real data for wide-angle cameras described by four parametric projection models. These tests reveal the strengths and weaknesses of these camera models, as well as the repeatability of these GCC tools. In view of the survey and evaluation, future research directions of wide-angle GCC are also discussed.

Camilo B. García, Luis O. Duarte

Landings of the artisanal fishery in the Colombian Caribbean from 2013 to 2021 were characterized by means of two indicators: the trophic level and the vulnerability to fishery landings. Indicators showed a statistically significant decreasing trend in vulnerability and trophic level, suggesting that the fishery is increasingly targeting species of low vulnerability and trophic level, thus moving down the food web. The overall pattern of indicators was not uniform in space. Incidence interaction of gears and species landed explained the trajectory of indicators at the scale of Departments. Fishing gears targeted different levels in the food web, with gillnets responsible for the bulk of landings. Compared to a previous study, the group of fish species supporting most of landings has changed towards species with lower vulnerability, i.e. resistant to fishing mortality due to their evolved life-history but still of predatory habits in general. A notable exception is Mugil incilis, a species with a low trophic level that has become third in importance of landings in the database.

Wajiha Javed, Sibgha Riaz, Ali Övgün

In this paper, we examine the weak deflection angle and greybody bound for magnetized regular black hole.$~$ For this purpose, we apply the Gauss-Bonnet theorem on the black hole and obtain the deflection angle in plasma and non-plasma mediums.$~$ Moreover, we investigate graphically the effect of impact parameter on the deflection angle for regular black hole in both mediums. We examine that deflection angle goes to infinity when the impact parameter approaches to zero. We also observe that deflection angle shows negative behaviour at $q=0.6$ and $q=2.09$ but at $0.6<q<2.09$, angle shows the positive behaviour. Furthermore, we study the rigorous bound phenomenon of the greybody factor in the background for magnetized regular black hole. Later, we analyze the graphical behaviour of greybody bound with respect to different values of $ω$ and observe that at small values of $ω$, bound is increasing but for large values, bound is decreasing. Afterthat we examine that when we put $G=1$, $l=0$ and $q=0$, then all results for magnetized regular black hole solution reduces into results of the Schwarzschild black hole solution.

Baichuan Jiang, Keshuai Xu, Abhay Moghekar et al.

Ultrasound-guided spine interventions, such as lumbar-puncture procedures, often suffer from the reduced visibility of key anatomical features such as the inter-spinous process space, due to the complex shape of the self-shadowing vertebra. Therefore, we propose to design a wearable 3D ultrasound device capable of imaging the vertebra from multiple insonification angles to improve the 3D bone surface visualization for interventional guidance. In this work, we aim to equip the imaging platform with a reconstruction algorithm taking advantage of the redundant ultrasound beam angles. Specifically, we try to weight each beam's contribution for the same reconstructed voxel during the reconstruction process based on its incidence angle to the estimated bone surface. To validate our approach, we acquired multi-angle ultrasound image data on a spine phantom with a tracked phased array transducer. The results show that with the proposed method the bone surface contrast can be significantly enhanced, providing clearer visual guidance for the clinician to perform spine intervention.

Ved Prakash Gupta, Deepika Sharma

We show that all values in the interval $[0,\fracπ{2}]$ can be attained as the interior angle between intermediate subalgebras (as introduced in [3]) of a certain inclusion of simple unital C*-algebras. We also calculate the interior angle between intermediate crossed product subalgebras of any inclusion of crossed product algebras corresponding to any action of a countable discrete group and its subgroups on a unital C*-algebra.

Adekunle David Micah, Bin Wen, Qin Wang et al.

To investigate the effects of dietary astaxanthin on fish growth and body color, blood parrotfish juveniles were assigned to three groups: control (CL), fed a diet without astaxanthin supplementation for 12 weeks; coloration (ASTA+), fed a diet containing 0.45 g/kg astaxanthin for 12 weeks; decoloration (ASTA-) fed the diet supplemented with astaxanthin for the first six weeks and then the control diet for the other six. Our results showed that the specific growth rate showed no significant difference between ASTA+ and CL at weeks 3 and 6 and among ASTA+ , ASTA- and CL at weeks 9 and 12. The ASTA+ group showed higher skin redness at weeks 3, 6, 9 and 12 and higher yellowness at weeks 6, 9 and 12 than CL, and than ASTA- at week 12. The ASTA+ group had higher concentrations of astaxanthin, HDL-C and LDL-C than the CL at weeks 3, 6, 9, and 12 and than ASTA- group at weeks 9 and 12. By compared ASTA+ and ASTA- with CL, a total of 4250 differentially expressed genes (DEGs) were detected. Pathways, e.g., PPRA signaling pathway, fatty acid degradation, and ABC transporters, of DEGs involved in carotenoid deposition were enriched. DEGs involved in the absorption and transport (e.g., upregulated lpl and pltp, and downregulated stard7), metabolism (e.g., upregulated adh1 and dhrs7cb, and downregulated cyp7b1, dhrs11, and si:ch211-113j14.1), and deposition of carotenoids (e.g., downregulated apoa1b and apodb) might be associated with skin coloration. Overall, the results of this study could help to understand the biochemical and molecular mechanism of body coloration under the presence and absence of dietary astaxanthin in blood parrotfish.

Joshua J. P Thompson, Samuel Brem, Hanlin Fang et al.

The optical properties of monolayer transition metal dichalcogenides are dominated by tightly-bound excitons. They form at distinct valleys in reciprocal space, and can interact via the valley-exchange coupling, modifying their dispersion considerably. Here, we predict that angle-resolved photoluminescence can be used to probe the changes of the excitonic dispersion. The exchange-coupling leads to a unique angle dependence of the emission intensity for both circularly and linearly-polarised light. We show that these emission characteristics can be strongly tuned by an external magnetic field due to the valley-specific Zeeman-shift. We propose that angle-dependent photoluminescence measurements involving both circular and linear optical polarisation as well as magnetic fields should act as strong verification of the role of valley-exchange coupling on excitonic dispersionand its signatures in optical spectra

William M. Guimarães, Cristiano M. B. Cordeiro, Marcos A. R. Franco et al.

We propose and theoretically study a new hollow-core fiber-based curvature sensor with the capability of detecting both bending magnitude and angle (direction). The new sensor relies on a tubular-lattice fiber that encompasses, in its microstructure, tubes with three different thicknesses. By adequately choosing the placement of the tubes within the fiber cross-section, and by exploring the spectral shifts of the fiber transmitted spectrum due to the curvature-induced mode field distributions' displacements, we demonstrate a multi-axis bending sensor. In the proposed sensor, curvature radii and angles are retrieved via a suitable calibration routine, which is based on conveniently adjusting empirical functions to the sensor response. Evaluation of the sensor performance for selected cases allowed to determine the curvature radii and angles with percentual errors of less than 7%. The approach proposed herein provides a promising path for the accomplishment of new curvature sensors able to resolve both the curvature magnitude and angle.

Tianjun Xu, Ye Li, Qing Chu et al.

Sciaenops ocellatus, also known as red drum, is a valuable commercial fish that is widely cultured in China. In recent years, while the genetic research and molecular breeding on S. ocellatus has been widely performed, whole-genome resources are lacking. In our study, we assembled the S. ocellatus genome by high-quality genome sequencing, followed by complete annotation. The size of final genome was 686.62 Mb and N50 length of contig and scaffold is 99.71 Kb and 25.62 Mb, respectively. Using the Hi-C technology, we obtained 24 pseudochromosomes containing 87.82% of the total scaffolds. We annotated 20,053 protein-coding genes in S. ocellatus genome, of which 99.93% were homologous to proteins in different database. Totally, we detected 133.54 Mb repeat sequences, which accounts for 19.45% of the assembly. According to the phylogenetic analysis, S. ocellatus is most closed to L. croea with a divergence time about 30 million years ago. We assembled a high-quality genome that will be a valuable resource to further study the biology of S. ocellatus and will inform how to breed the red drum to enhance its economic traits.

Pavel A. Volkov, Justin H. Wilson, Kevin Lucht et al.

Motivated by recent advances in the fabrication of twisted bilayers of 2D materials, we consider the low-energy properties of a twisted pair of two-dimensional nodal superconductors. We study both the cases of singlet and triplet superconductors. It is demonstrated that the Bogoliubov-de Gennes (BdG) quasiparticle dispersion undergoes dramatic reconstruction due to the twist. In particular, the velocity of the neutral massless Dirac excitations near the gap nodes is strongly renormalized by the interlayer hopping and vanishes at a ``magic angle'' where in the limit of a circular Fermi surface a quadratic band touching is formed. In addition, it is shown that the BdG disperion can be tuned with an interlayer displacement field, magnetic field, and current, which can suppress the velocity renormalization, create finite BdG Fermi surfaces, or open a gap, respectively. Finally, interactions between quasiparticles are shown to lead to the emergence of a correlated superconducting state breaking time-reversal symmetry in the vicinity of the magic angle. Estimates of the magic angle in a variety of nodal superconductors are presented, ranging from the cuprates to the organic and heavy fermion superconductors, all of which are shown to be promising for the experimental realization of our proposal.

Kanwar Bharat Singh

Information about the vehicle sideslip angle is crucial for the successful implementation of advanced stability control systems. In production vehicles, sideslip angle is difficult to measure within the desired accuracy level because of high costs and other associated impracticalities. This paper presents a novel framework for estimation of the sideslip angle. The proposed algorithm utilizes an adaptive tire model in conjunction with a model-based observer. The developed algorithm is evaluated through experimental tests on a rear wheel drive vehicle. Detailed experimental results show that the developed system can reliably estimate the vehicle sideslip angle during both steady state and transient maneuvers.