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Articles 58471 - 58500 of 302422

Full-Text Articles in Physical Sciences and Mathematics

Seasonal Dynamics In Fish Distribution And Abundance Revealed By An Acoustic Survey In Coastal Waters Of The Suzu Area, Kochi Prefecture, Japan, Yanhui Zhu, Kenji Minami, Yuka Iwahara, Kentaro Oda, Koichi Hidaka, Osamu Hoson, Koji Morishita, Sentaro Tsuru, Masahito Hirota, Hokuto Shirakawa, Kazushi Miyashita May 2021

Seasonal Dynamics In Fish Distribution And Abundance Revealed By An Acoustic Survey In Coastal Waters Of The Suzu Area, Kochi Prefecture, Japan, Yanhui Zhu, Kenji Minami, Yuka Iwahara, Kentaro Oda, Koichi Hidaka, Osamu Hoson, Koji Morishita, Sentaro Tsuru, Masahito Hirota, Hokuto Shirakawa, Kazushi Miyashita

Journal of Marine Science and Technology

For Japan's fishery, it is essential to conduct sustainable and efficient fishery owing to the decline in fish catch as well as the fisher population. To obtain information that contributes to sustainable and efficient fishery, we researched appropriate set-net locations with regard to fish distribution, abundance, and environmental characteristics. We conducted surveys from 2017/5 to 2018/2 in the Suzu coastal area, Kochi Prefecture, where the only main industry is set-net fishery. We investigated the seasonal relationships between fish school characteristics, including distribution and size, and marine environmental conditions in the Suzu coastal area, using a quantitative echo sounder (KSE300 SONIC, …


Development Of A Biomass Assessment Method Using Fisheries Echo Sounder For Monitoring Whitebait Fishery In Shizuoka Prefecture, Japan, Kenichi Kobayashi, Yanhui Zhu, Daichi Oshiyama, Kenji Minami, Hokuto Shirakawa, Kazushi Miyashita May 2021

Development Of A Biomass Assessment Method Using Fisheries Echo Sounder For Monitoring Whitebait Fishery In Shizuoka Prefecture, Japan, Kenichi Kobayashi, Yanhui Zhu, Daichi Oshiyama, Kenji Minami, Hokuto Shirakawa, Kazushi Miyashita

Journal of Marine Science and Technology

Coastal fisheries constitute the second most important sector in fishery production in Japan, following offshore fisheries. Thus, spatial evaluation of coastal fishing grounds and understanding of the changes in biomass are important for the sustainable use of fishing resources. For the assessment of spatial fish biomass, a quantitative echo sounder is used, but such a device is not mass produced and involves a high cost. In the present study, we examined the feasibility of biomass assessment using typical commercial fisheries echo sounders that are widely used and cheaper than quantitative echo sounders. Therefore, we aimed to verify the validity of …


Herbage Biomass Production And Nutritive Value Of Morus Alba And Calliandra Calothyrsus Harvested At Different Cutting Frequencies, Fred Kabi, F. B. Bareeba May 2021

Herbage Biomass Production And Nutritive Value Of Morus Alba And Calliandra Calothyrsus Harvested At Different Cutting Frequencies, Fred Kabi, F. B. Bareeba

IGC Proceedings (1993-2023)

No abstract provided.


Amino Acid And Protein Incorporation In Water‐Stressed Perennial Ryegrass, W. J. Jung, B. R. Lee, L. S. Li, Y. L. Jin, T. H. Kim May 2021

Amino Acid And Protein Incorporation In Water‐Stressed Perennial Ryegrass, W. J. Jung, B. R. Lee, L. S. Li, Y. L. Jin, T. H. Kim

IGC Proceedings (1993-2023)

No abstract provided.


Quality Of High Moisture Corn Silage Added Of Whole Soybean, Whole Sunflower Or Urea, C. C. Jobim, F. A. F. Macedo, A. F. Branco, C. R. Alcalde May 2021

Quality Of High Moisture Corn Silage Added Of Whole Soybean, Whole Sunflower Or Urea, C. C. Jobim, F. A. F. Macedo, A. F. Branco, C. R. Alcalde

IGC Proceedings (1993-2023)

No abstract provided.


Carcass Characteristics Of Sheep Fed High Moisture Corn Silage With Or Without Whole Sunflower Or Urea Finished In Feedlot, C. C. Jobim, F. A. F. Macedo, A. F. Branco, L. Lombardy May 2021

Carcass Characteristics Of Sheep Fed High Moisture Corn Silage With Or Without Whole Sunflower Or Urea Finished In Feedlot, C. C. Jobim, F. A. F. Macedo, A. F. Branco, L. Lombardy

IGC Proceedings (1993-2023)

No abstract provided.


Modeling Biliary Polycyclic Aromatic Hydrocarbon Metabolites In Fish Using High Performance Liquid Chromatography With Fluorescence Detection, Principal Component Analysis, And Partial Least-Squares Analysis, Joshua C. Padilla May 2021

Modeling Biliary Polycyclic Aromatic Hydrocarbon Metabolites In Fish Using High Performance Liquid Chromatography With Fluorescence Detection, Principal Component Analysis, And Partial Least-Squares Analysis, Joshua C. Padilla

Honors Projects

Polycyclic aromatic hydrocarbons (PAHs) constitute a diverse class of highly toxic, ubiquitous environmental pollutants, and are thus of high interest in environmental monitoring and regulation. In this study, biliary samples of English soles Parophrys vetulus and smallmouth bass Micropterus dolomieu from Seattle waterways, and chum salmon Onchorynchus keta from the north Pacific Ocean were analyzed by high performance liquid chromatography with fluorescence detection (HPLC-FLD) to gauge PAH exposure. Samples were profiled in three broad molecular weight categories, to capture naphthalene-like (NAPH), phenanthrene-like (PHEN), and benzo[a]pyrene-like (BAP) metabolites. While quantification was not achieved for the chum salmon, the semi-quantitative measurements of …


Integrated Shift And Drift Control Of A Non-Linear Growth Process., Soham Chakraborty Dr. May 2021

Integrated Shift And Drift Control Of A Non-Linear Growth Process., Soham Chakraborty Dr.

Doctoral Theses

In the field of Quality Control (QC), the term 'control' is used to mean many different things. For example, it may refer to an isolated control action (e.g. a process adjustment), a particular type of control architecture (e.g. feedback vs. feed forward control) or even a control discipline (e.g. Deming's PDCA cycle). So will be the case here. But the exact meaning will be clear from the context.Since the development of control chart by Shewhart [1] and the method of acceptance sampling by Dodge and Romig [2] during 1920's - 1940's, the field of quality control has been greatly enriched …


Effects Of Air Pollution, Temperature And Moisture Content On Copper And Silver Corrosions And The Reliability Of Data Center Equipment, Rui Zhang May 2021

Effects Of Air Pollution, Temperature And Moisture Content On Copper And Silver Corrosions And The Reliability Of Data Center Equipment, Rui Zhang

Dissertations - ALL

The effects of moisture content, temperature, and pollutant mixture on atmospheric corrosion of copper and silver were investigated by exposing test specimens to different environmental conditions, followed by surface characterization using the coulometric reduction, Scanning Electron Microscopy, and Energy Dispersive Spectrometry (SEM/EDS). Printed circuit board test cards (PCBs) with bare copper were also used to investigate the effects of voltage bias on the PCBs on the corrosion rate. The test specimens were exposed to mixed flowing gases (MFG) environment with eight different combinations of the following five pollutants at the fixed concentration levels: 60 ppb O3, 80 ppb NO2, 40 …


Hot Planets Around Cool Stars – Two Short-Period Mini-Neptunes Transiting The Late K-Dwarf Toi-1260, I. Y. Georgieva, C. M. Persson, O. Barragán, G. Nowak, M. Fridlund, D. Locci, E. Palle, R. Luque, I. Carleo, D. Gandolfi, S. R. Kane, J. Korth, K. G. Stassun, J. Livingston, E. C. Matthews, K. A. Collins, S. B. Howell, L. M. Serrano, S. Albrecht, A. Bieryla, C. E. Brasseur, D. Ciardi, W. D. Cochran, K. D. Colon, I. J. M. Crossfield, S. Csizmadia, H. J. Deeg, M. Esposito, E. Furlan, T. Gan, E. Goffo, E. Gonzales, S. Grziwa, E. W. Guenther, P. Guerra, T. Hirano, J. M. Jenkins, Eric L.N. Jensen, P. Kabáth, E. Knudstrup, K. W. F. Lam, D. W. Latham, A. M. Levine, R. A. Matson, S. Mcdermott, H. L. M. Osborne, M. Paegert, S. N. Quinn, S. Redfield, G. R. Ricker, J. E. Schlieder, N. J. Scott, S. Seager, A. M. S. Smith, P. Tenenbaum, J. D. Twicken, R. Vanderspek, V. Van Eylen, J. N. Winn May 2021

Hot Planets Around Cool Stars – Two Short-Period Mini-Neptunes Transiting The Late K-Dwarf Toi-1260, I. Y. Georgieva, C. M. Persson, O. Barragán, G. Nowak, M. Fridlund, D. Locci, E. Palle, R. Luque, I. Carleo, D. Gandolfi, S. R. Kane, J. Korth, K. G. Stassun, J. Livingston, E. C. Matthews, K. A. Collins, S. B. Howell, L. M. Serrano, S. Albrecht, A. Bieryla, C. E. Brasseur, D. Ciardi, W. D. Cochran, K. D. Colon, I. J. M. Crossfield, S. Csizmadia, H. J. Deeg, M. Esposito, E. Furlan, T. Gan, E. Goffo, E. Gonzales, S. Grziwa, E. W. Guenther, P. Guerra, T. Hirano, J. M. Jenkins, Eric L.N. Jensen, P. Kabáth, E. Knudstrup, K. W. F. Lam, D. W. Latham, A. M. Levine, R. A. Matson, S. Mcdermott, H. L. M. Osborne, M. Paegert, S. N. Quinn, S. Redfield, G. R. Ricker, J. E. Schlieder, N. J. Scott, S. Seager, A. M. S. Smith, P. Tenenbaum, J. D. Twicken, R. Vanderspek, V. Van Eylen, J. N. Winn

Physics & Astronomy Faculty Works

We present the discovery and characterization of two sub-Neptunes in close orbits, as well as a tentative outer planet of a similar size, orbiting TOI-1260 – a low metallicity K6 Vdwarf star. Photometry from TESS yields radii of Rb = 2.33 ± 0.10 R⊕ and Rc = 2.82 ± 0.15 R⊕, and periods of 3.13 and 7.49 days for TOI-1260 b and TOI-1260 c, respectively. We combined the TESS data with a series of ground-based follow-up observations to characterize the planetary system. From HARPS-N high-precision radial velocities we obtain Mb =8.6+1.4−1.5 M⊕ and Mc =11.8+3.4−3.2 M⊕. The star is moderately …


Exploring The Mechanism Of The Electrostatic Denaturation Of Double-Stranded Dna, Gayatri Raghu May 2021

Exploring The Mechanism Of The Electrostatic Denaturation Of Double-Stranded Dna, Gayatri Raghu

Master's Theses

Electrostatic melting is an electrochemical tool that can be used to analyze the stability of DNA, allowing for the detection of various mutations in double-stranded DNA (dsDNA). Here, we explore the influence of electrostatic double layer formation on the unzipping of dsDNA to better comprehend the mechanism of this process. Previous studies by our lab show that the melting curve produced can distinguish between fully complementary 34-bp strands and a version of the same sequence in which one base pair has been replaced with a mismatch pair or detect and characterize the crosslinking of the dsDNA by anticancer drug cisplatin. …


The Regiochemistry And Relative Reaction Rates Of Methylbiphenyl Isomers In Electrophilic Aromatic Substitution Reaction (Eas) Nitrations Suggest A Non-Planar Geometry For 2-Methylbiphenyl While 3- And 4-Methylbiphenyl Remain Planar, Tristan Pj Wine May 2021

The Regiochemistry And Relative Reaction Rates Of Methylbiphenyl Isomers In Electrophilic Aromatic Substitution Reaction (Eas) Nitrations Suggest A Non-Planar Geometry For 2-Methylbiphenyl While 3- And 4-Methylbiphenyl Remain Planar, Tristan Pj Wine

Honors Projects

Electrophilic aromatic substitution (EAS) reactions have long been a fundamental addition to sophomore-level organic chemistry classes, allowing students the opportunity to explore the electron donating and withdrawing effects of electrons contained in the substituents of the aromatic reactant. In this paper we present preliminary findings on the nitration of methylated biphenyls using kinetic and regioselective assessments to analyze steric influences on the planarization of 2-methylbiphenyl after EAS nitration. Our preliminary findings show that nitration favors the methylated phenyl ring of 2-methylbiphenyl, indicating that the steric influence of the methyl group restricts planarization of the carbocation intermediate. Furthermore, a competition nitration …


Salicylic Acid Response To Simulated Herbivory In Geographically Distinct T. Heterophylla And H. Discolor Populations, Amy E. Castle May 2021

Salicylic Acid Response To Simulated Herbivory In Geographically Distinct T. Heterophylla And H. Discolor Populations, Amy E. Castle

Honors Projects

It is commonly known that plants may produce salicylic acid as a chemical defense response to wounding, although the phenomenon has usually been observed with regard to insect herbivory. Stem and leaf tissue of two species, Tsuga heterophylla and Holodiscus discolor, which are often eaten by deer, were extracted in methanol and analyzed by HPLC to quantify salicylic acid concentration in experimentally wounded or control samples. No salicylic acid response was detectable in T. heterophylla, suggesting it is a less useful candidate species for future study. Some but not all H. discolorsamples had a measurable salicylic acid …


Mesoproterozoic Basement From The Central And Southern Appalachians Reveal High-Temperature Magmatic Conditions And Non-Laurentian Origin Of Earth’S Most Zircon Fertile Magmas, Kyle Makovsky May 2021

Mesoproterozoic Basement From The Central And Southern Appalachians Reveal High-Temperature Magmatic Conditions And Non-Laurentian Origin Of Earth’S Most Zircon Fertile Magmas, Kyle Makovsky

Dissertations - ALL

The Mesoproterozoic (1.4-0.9 Ga) Grenville Orogeny led to the formation of the supercontinent Rodinia. One unique characteristic of the Grenville Orogeny is that it produced a volumetrically significant amount of zirconium- (Zr) enriched granitoids, evidently more than any period both prior to and after the Grenville. To investigate this further, Mesoproterozoic basement rocks were sampled along the axis of the current Appalachian Mountains from western North Carolina north to southern New York, as well as from the northern Andes in southern Colombia. Zircon was extracted from these rocks to exploit its propensity to incorporate several isotopic tracers useful in determining …


Three Essays On Climate Change Adaptation In Rural African Communities, Hannah Patnaik May 2021

Three Essays On Climate Change Adaptation In Rural African Communities, Hannah Patnaik

Dissertations - ALL

Climate change is one of the defining challenges of the present era, bringing new risks and exacerbating existing vulnerabilities across the world. While there is a broad recognition that solutions around climate change will require coordination and support across borders and governments, a large body of scholarship has focused on the local-level realities of climate change and the disproportionate impacts on the most vulnerable populations. The climate vulnerable poor do not have the privilege of waiting for global policy and commitment to emission reduction targets. They need planned and proactive adaptation support to build resilience to the changing climate and …


Using An Integrative Machine Learning Approach To Study Microrna Regulation Networks In Pancreatic Cancer Progression, Roland Madadjim May 2021

Using An Integrative Machine Learning Approach To Study Microrna Regulation Networks In Pancreatic Cancer Progression, Roland Madadjim

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

With advances in genomic discovery tools, recent biomedical research has produced a massive amount of genomic data on post-transcriptional regulations related to various transcript factors, microRNAs, lncRNAs, epigenetic modifications, and genetic variations. In this direction, the field of gene regulation network inference is created and aims to understand the interactome regulations between these molecules (e.g., gene-gene, miRNA-gene) that take place to build models able to capture behavioral changes in biological systems. A question of interest arises in integrating such molecules to build a network while treating each specie in its uniqueness. Given the dynamic changes of interactome in chaotic systems …


Optimization And Characterization Of Doped Optical Fibers For Radiation Balanced Fiber Laser And Amplifier, Mostafa Peysokhan May 2021

Optimization And Characterization Of Doped Optical Fibers For Radiation Balanced Fiber Laser And Amplifier, Mostafa Peysokhan

Optical Science and Engineering ETDs

Due to the reliability, compactness, low maintenance costs, superior performance, and versatility of fiber lasers and amplifiers, they are commonly employed in scientific and directed energy applications. Among all kinds of fiber lasers and amplifiers, high-power, Yb-dopped fiber lasers and amplifiers have been extensively researched to achieve higher output powers. One of the major hindrances to achieving higher powers with adequate stability and efficiency in high power performance is heat generated in the fiber lasers and amplifiers' core. The Radiation Balanced Laser (RBL) is a viable technique for heat mitigation has been proposed by S.~Bowman in 1995. RBL technique is …


Beyond The Standard Models Of Particle Physics And Cosmology, Gabriele Rigo May 2021

Beyond The Standard Models Of Particle Physics And Cosmology, Gabriele Rigo

Dissertations - ALL

Despite their numerous successes both from the theoretical and experimental point of view, conceptual and observational evidence suggests the Standard Models of Particle Physics and Cosmology should be considered incomplete theories, reliable only within their well-defined regime of validity. This dissertation covers various possible extensions of those models from the theoretical, phenomenological and model-building perspective. The topics analyzed range from extra-dimensional approaches to the hierarchy problem, to the AdS/CFT description of perturbative anomaly inflow, and new probes of vacuum energy in neutron stars and gravitational waves.


Sentiment Classification Bias In User Generated Content, Alpana Deshpande May 2021

Sentiment Classification Bias In User Generated Content, Alpana Deshpande

Theses - ALL

Interactive websites generate terabytes of data on a daily basis. This data canbe used in multiple analytical applications to teach computers more about human behavior. Text classification is such an application. Multiple freely available user-generated text data can be used to teach computers to identify the sentiments behind a user’s on-screen interactions without the need of any human intervention. Sentiment analysis is an interesting problem, solving which would theoretically get a computer closer to passing the Turing test. Through this thesis, we test the ability of a classifier to accurately identify user sentiments. However, we do not focus on standard …


Enhancing Usability Of Malware Analysis Pipelines With Reverse Engineering, Jeffrey Ching May 2021

Enhancing Usability Of Malware Analysis Pipelines With Reverse Engineering, Jeffrey Ching

Theses - ALL

Lots of work has been done on analyzing software distributed in binary form. This is a challenging problem because of the relatively unstructured nature of binaries. To recover high-level structure, various attempts have included static and dynamic analysis. However, human inspection is often required, as high-level structure is compiled away. Recent success in this area includes work on variable-name recovery, vulnerability discovery, class recovery for object-oriented languages. We are interested in building a pipeline for user to analyze malware. In this thesis we tackle two problems central to malware analysis pipelines. The first is D3RE, an interactive querying tool that …


Carbonate Paleothermometry In Fayetteville Green Lake, New York, Micah Wiesner May 2021

Carbonate Paleothermometry In Fayetteville Green Lake, New York, Micah Wiesner

Theses - ALL

Lacustrine carbonates are important paleoclimate archives, but unknowns in the seasonal timing and depth of precipitation obscure the interpretation of temperatures associated with them. The clumped isotope paleothermometer records the formation temperature T(D47) of carbonates. This study examines a set of lacustrine carbonates formed in the water column, in addition to carbonate from a sediment core, to better understand the depth and seasonality of carbonate formation in a lacustrine setting. We test that, regardless of season and formation temperature, lacustrine carbonates form in isotopic equilibrium with respect to D47 and d18O fractionation. Further, we account for the effect of our …


Ambient Obstruction Solitons And Homogeneous Gradient Bach Solitons, Erin Renee Griffin May 2021

Ambient Obstruction Solitons And Homogeneous Gradient Bach Solitons, Erin Renee Griffin

Dissertations - ALL

Differential geometry is a diverse field which applies principles from calculus to a more general set of objects. Endowing a smooth manifold with a Riemannian metric allows us to measure length and angle in a way such that length is positive. This enables us to examine measures of curvature on a manifold. The study of manifolds with such metrics is called Riemannian geometry. Using geometric flows associated with tensors, we are able to analyze the relationship between metrics and curvature. Examining solitons, specifically gradient solitons, is one way we investigate this relationship.

This thesis focuses on the geometric flows associated …


N-Bakry Emery Ricci Curvature & N-Quasi Einstein Metrics, Alice Wu Lim May 2021

N-Bakry Emery Ricci Curvature & N-Quasi Einstein Metrics, Alice Wu Lim

Dissertations - ALL

We begin the thesis by giving an intuitive introduction to calculus on mani- folds for the non-mathematician. We then give a semi-intuitive description on Ricci curvature for the non-geometer. We give a description of the N-Bakry- Émery Ricci curvature and the N-quasi Einstein metric. The main results in this thesis are related to the N-Bakry-Émery Ricci curvature and the N-quasi Einstein metric.

Our first set of main results are as follows. We generalize topological results known for noncompact manifolds with nonnegative Ricci curvature to spaces with nonnegative N-Bakry Émery Ricci curvature. We study the Splitting Theorem and a property called …


Torsion Subgroups Of Rational Elliptic Curves Over Odd Degree Galois Fields, Caleb Mcwhorter May 2021

Torsion Subgroups Of Rational Elliptic Curves Over Odd Degree Galois Fields, Caleb Mcwhorter

Dissertations - ALL

The Mordell-Weil Theorem states that if K is a number field and E/K is an elliptic curve that the group of K-rational points E(K) is a finitely generated abelian group, i.e. E(K) = Z^{r_K} ⊕ E(K)_tors, where r_K is the rank of E and E(K)_tors is the subgroup of torsion points on E. Unfortunately, very little is known about the rank r_K. Even in the case of K = Q, it is not known which ranks are possible or if the ranks are bounded. However, there have been great strides in determining the sets E(K)_tors. Progress began in 1977 with …


Hochschild Cohomology Of Short Gorenstein Rings, Mkrtich Ohanyan May 2021

Hochschild Cohomology Of Short Gorenstein Rings, Mkrtich Ohanyan

Dissertations - ALL

Let k be a field of characteristic 0. In this thesis, we show that the Hochschild cohomology of the family of short Gorenstein k-algebras

sGor(N) =k[X_0,...,X_N](X_iX_j, X_i^2−X_j^2 | i,j= 0,...,N, i different from j), N≥2,

exhibits exponential growth. The proof uses Gröbner-Shirshov basis theory and along the way we describe an explicit monomial basis for the Koszul dual of sGor(N) for N≥2.


Inferring Degree Of Localization Of Twitter Persons And Topics Through Time, Language, And Location Features, Aleksey Valeriy Panasyuk May 2021

Inferring Degree Of Localization Of Twitter Persons And Topics Through Time, Language, And Location Features, Aleksey Valeriy Panasyuk

Dissertations - ALL

Identifying authoritative influencers related to a geographic area (geo-influencers) can aid content recommendation systems and local expert finding. This thesis addresses this important problem using Twitter data.

A geo-influencer is identified via the locations of its followers. On Twitter, due to privacy reasons, the location reported by followers is limited to profile via a textual string or messages with coordinates. However, this textual string is often not possible to geocode and less than 1\% of message traffic provides coordinates. First, the error rates associated with Google's geocoder are studied and a classifier is built that gives a warning for self-reported …


Experience-Driven Control For Networking And Computing, Zhiyuan Xu May 2021

Experience-Driven Control For Networking And Computing, Zhiyuan Xu

Dissertations - ALL

Modern networking and computing systems have become very complicated and highly dynamic, which makes them hard to model, predict and control. In this thesis, we aim to study system control problems from a whole new perspective by leveraging emerging Deep Reinforcement Learning (DRL), to develop experience-driven model-free approaches, which enable a network or a device to learn the best way to control itself from its own experience (e.g., runtime statistics data) rather than from accurate mathematical models, just as a human learns a new skill (e.g., driving, swimming, etc). To demonstrate the feasibility and superiority of this experience-driven control design …


Acoustic Survey For Estimating Density Of Anchovy Schools In The South Sea Of Korea, Eunbi Min, Eun-A Yoon, Sung-Tae Kim, Seong Yong Moon, Hyun Woo Kim, Shelly Salim, Taejong Kang, Doo-Jin Hwang May 2021

Acoustic Survey For Estimating Density Of Anchovy Schools In The South Sea Of Korea, Eunbi Min, Eun-A Yoon, Sung-Tae Kim, Seong Yong Moon, Hyun Woo Kim, Shelly Salim, Taejong Kang, Doo-Jin Hwang

Journal of Marine Science and Technology

No abstract provided.


Estimating The Sampling Efficiencies Of A Framed Midwater Trawl And Ring Net For Zooplankton Using An Acoustic Method, Zhen Lu, Tohru Mukai, Yasuzumi Fujimori, Kohji Iida May 2021

Estimating The Sampling Efficiencies Of A Framed Midwater Trawl And Ring Net For Zooplankton Using An Acoustic Method, Zhen Lu, Tohru Mukai, Yasuzumi Fujimori, Kohji Iida

Journal of Marine Science and Technology

It is well known that there is bias using different sampling gear, such as a framed midwater trawl (FMT) and a ring net, when measuring the density and length distribution of target species. This limit is characterized by the sampling efficiency of the gear. Acoustic monitoring can be used to determine the sampling efficiencies of this gear, as its noninvasive, wide-range sweeps provide more reliable estimates of absolute abundance of the target species. The density measured by the gear can then be standardized by multiplying the initial density measurement by the derived sampling efficiency. In this study, we compared the …


In Situ Broadband Acoustic Measurements Of Age-0 Walleye Pollock And Pointhead Flounder In Funka Bay, Hokkaido, Japan, Kohei Hasegawa, Naizheng Yan, Tohru Mukai May 2021

In Situ Broadband Acoustic Measurements Of Age-0 Walleye Pollock And Pointhead Flounder In Funka Bay, Hokkaido, Japan, Kohei Hasegawa, Naizheng Yan, Tohru Mukai

Journal of Marine Science and Technology

Measurements of the broadband acoustic backscattering from fish should improve acoustic discrimination between species. The pulse compression processing of broadband systems can be used to measure acoustic backscattering with high range resolution and improve signal-to-noise ratio. This may increase opportunities for in situ target strength (TS) measurements, the preferred method of collecting TS data. To evaluate the availability of TS spectra for acoustic discrimination, three Simrad EK80 wideband transceivers and split-beam transducers of 70, 120, and 200 kHz were used to collect in situ frequency responses of TS from age-0 juvenile walleye pollock and pointhead flounder, a swimbladderless flat-fish, distributed …