Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 69811 - 69840 of 1337942

Full-Text Articles in Entire DC Network

Application Of Lossy And Lossless Compression To Dicom Files, Yizhe Yang Dec 2024

Application Of Lossy And Lossless Compression To Dicom Files, Yizhe Yang

All Theses

The Digital Imaging and Communications in Medicine (DICOM) standard is widely utilized for the management, storage, and transfer of medical images. However, the substantial file sizes associated with DICOM data present challenges in terms of storage and data transmission. Data reduction techniques help address these challenges by minimizing the size of the data while preserving its integrity. This thesis examines various compression methods aimed at reducing the size of DICOM files. We evaluate five lossless compressors and four lossy compressors on DICOM data to compare and assess their performance. Through an analysis of each compressor’s compression efficiency and resulting image …


Informing Management Of American Shad (Alosa Sapidissima) In The Carolinas: Evaluating Novel Fish Passage Approaches And Acoustic Tracking Methods, Margaret Gaither Dec 2024

Informing Management Of American Shad (Alosa Sapidissima) In The Carolinas: Evaluating Novel Fish Passage Approaches And Acoustic Tracking Methods, Margaret Gaither

All Theses

Acoustic telemetry is a valuable tool for fisheries scientists to study the movements and migratory behaviors of aquatic organisms. A critical assumption of this method is that tagged fish exhibit similar behaviors and survival rates as their untagged counterparts. To investigate this, we conducted a 12-week laboratory study on adult American Shad (Alosa sapidissima) using gastroesophageal insertion of acoustic transmitters. We implanted 80 fish with dummy transmitters and monitored tag retention and survival. Our analysis, employing a mixed effects Cox’s proportional hazards model, revealed no significant differences in survival between tagged and control fish, regardless of sex. Additionally, …


Optimizing Sublimation Transfer Printing: Influence Of Temperature And Dwell Time On Different Synthetic Fabrics With A Focus On Color Metrics And Delta E Evaluation, Ramya Potnis Dec 2024

Optimizing Sublimation Transfer Printing: Influence Of Temperature And Dwell Time On Different Synthetic Fabrics With A Focus On Color Metrics And Delta E Evaluation, Ramya Potnis

All Theses

Various techniques are employed to create images on textile fabrics. This study utilized a dye sublimation transfer process to print onto synthetic textile fabrics. Sublimation transfer printing is a widely used method for applying designs onto fabrics. However, achieving consistent and accurate color reproduction remains a significant challenge. Factors such as temperature and dwell time can heavily influence the color accuracy and overall quality of the prints, making it essential to study their effects.

The study focuses on the influence of temperature and dwell time to evaluate the color quality of the sublimation transfer prints across different synthetic fabrics. The …


The Effect Of Packaging On The Acceptance Of Natural Peanut Butter, Perian M. Reese Dec 2024

The Effect Of Packaging On The Acceptance Of Natural Peanut Butter, Perian M. Reese

All Theses

The aim was to determine the effect of packaging on the acceptance of natural peanut butter, especially concerning the acceptance of the undesirable oil layer. The jars of peanut butter differed by color, label size, and inclusion of qualifying statements. 119 participants across two groups completed this study. Both groups completed an eye-tracking study in a mock grocery setting. The first group rated all five jars in appearance, expected quality, and overall rating. They were given one sample cup of peanut butter and gave hedonic liking values for color, oiliness, peanut flavor, smoothness, sweetness, and overall liking. The second group …


Investigation Of Chondrogenesis, Myogenesis, And Osteogenesis After 2,4-Dtbp, 2-Bp, 4-Bp, 3,5-Dtbc Exposure In Zebrafish, Haley Brashears Dec 2024

Investigation Of Chondrogenesis, Myogenesis, And Osteogenesis After 2,4-Dtbp, 2-Bp, 4-Bp, 3,5-Dtbc Exposure In Zebrafish, Haley Brashears

All Theses

Synthetic phenolic antioxidants (SPAs) are used in personal care products, food packaging, and water pipes, common SPAs include 2,4-di-tert-butylphenol (2,4-DTBP), 2-tert-butyl phenol (2-BP), and 4-tert-butyl phenol (4-BP). These compounds are detected in the environment and in human biological samples. 2,4-DTBP has been detected in cord plasma, placenta, and breast milk samples. This drives the concern regarding developmental toxicity. In human iPS cells 2,4-DTBP impairs differentiation into somites and osteoblasts. Other SPAs, like 2,6-di-tert-butyl-hydroxytoluene caused increased rates of malformations including yolk and pericardial edema, and spinal curvature in 5-day post fertilization (dpf) zebrafish. …


Influence Of Hygrothermal Conditions Of The Bistability Of Asymmetric Carbon Fiber Laminate Composites, Celia Hill Dec 2024

Influence Of Hygrothermal Conditions Of The Bistability Of Asymmetric Carbon Fiber Laminate Composites, Celia Hill

All Theses

Carbon fiber-reinforced polymer (CFRP) laminates have widespread use in many industries because of their exceptional strength-to-weight ratio. Carbon fiber laminates following an asymmetric layup orientation can exhibit bistability meaning the laminate can exist at two stable geometric configurations. The morphing characteristics of bistable CRFP has a growing level of interest because of its potential in various applications including space aircraft structures for easy repair, automotive structures for energy dissipation and ergonomics, robotics for flexible motion and energy harvesting. Existing research shows that both moisture and temperature affect the material properties and behavior of CFRP laminates, however, the influence of moisture …


Bounding The Convex Hull Relaxation Of The Unit Commitment Problem With The Shapley-Folkman Theorem, Lauren Henderson Dec 2024

Bounding The Convex Hull Relaxation Of The Unit Commitment Problem With The Shapley-Folkman Theorem, Lauren Henderson

All Theses

The Unit Commitment (UC) problem finds an optimal schedule for a set of generators by minimizing the total operation cost subject to demand and operational constraints. The UC problem is often modeled with a mixed-integer linear program (MILP). We employ the Shapley-Folkman Theorem to provide a bound on the size of fractional solutions of its convex hull relaxation. This result is used to obtain a bound on the optimality gap between the MILP and the convex hull relaxation, which is further tightened using several problem-specific properties of UC. We conduct extensive numerical experiments to study the tightness of this threshold, …


The Relationship Between Aging Perceptions And Cognition Among Older Adults: A Cross-Sectional Study Using The Enact And Efit Studies, Ava Mcvey Dec 2024

The Relationship Between Aging Perceptions And Cognition Among Older Adults: A Cross-Sectional Study Using The Enact And Efit Studies, Ava Mcvey

All Theses

Maintaining cognition is critical to overall health and independence. While lifestyle predictors (e.g., cognitive engagement, social engagement, physical activity) of cognition have been established in current research, the relationship of one’s perceptions of aging and cognition have been less thoroughly investigated. This thesis cross-sectionally explores the relationships between self-perceptions of aging (SPA; including awareness of age-related change and expectations regarding aging) and cognition, including performance-based measures of executive function (Matrix Reasoning, Letter/Number Switching, Digit Symbol, Trails A & B, Visual Paired Associates) and self-reported cognition (Cognitive Self Report Questionnaire). Participants include community dwelling older adults from two studies: the Elucidating …


Comparing The Effects Of Traffic Speed And Driver Assistance On Different Age Groups: Mixed Methods User Testing, Alan Mintz Dec 2024

Comparing The Effects Of Traffic Speed And Driver Assistance On Different Age Groups: Mixed Methods User Testing, Alan Mintz

All Theses

Although much research exists investigating preferences towards transportation and driver assistance technologies, there is a gap in the literature related to taking a mixed methods approach investigating age-related differences in traffic management behaviors. Previous studies have established that older adults tend to avoid higher risk traffic situations more often than younger adults. This research builds on existing work that compares different aged participants simulated driving behaviors, self-reported workload, and interview responses. Benefits from this study include adding to our understanding of gap maintenance behavior, perceived workload at varying traffic speeds, and preferences among younger and older drivers towards offloading driving …


An Analysis Of The Properties Of Polar Codes, Luke Szramowski Dec 2024

An Analysis Of The Properties Of Polar Codes, Luke Szramowski

All Theses

Polar Codes have risen to the forefront of practical coding theory, due to their incredible efficiency and ease of construction. Originally introduced by Arikan in his 2009 paper, they are the first code defined with an explicit construction that achieved channel capacity. Moreover, polar codes possess some physically practical properties that make their implementation alluring. In the same paper as mentioned above, Arikan elaborated on his construction and noted that the construction given was one specific instance of a polar code and that there is a family of polar codes that can be produced by the same method. Since this …


The Effect Of Pressure Gradients On Perceived Discomfort, Zachary Bush Dec 2024

The Effect Of Pressure Gradients On Perceived Discomfort, Zachary Bush

All Theses

Introduction:

A pressure gradient is where high and low pressure meet. It is responsible for displacement and irritation of the skin commonly caused by tight bandages, bracelets, or socks. The irritation is at the edge where the skin is displaced by the high and low pressure. An analysis of the effect pressure gradients have on discomfort would have significant medical relevance for any device, fixture, or clothing pressed against the skin at high pressure. This primarily includes prosthetic and orthotic devices.

The bottom surface of the heel provides a naturally circular, uniform pressure profile. This makes it the optimal testing …


Synthesis Of Binary-Input Multi-Valued Output Optical Cascades For Reversible And Quantum Technologies, Ishani Agarwal, Miroslav Saraivanov, Marek Perkowski Dec 2024

Synthesis Of Binary-Input Multi-Valued Output Optical Cascades For Reversible And Quantum Technologies, Ishani Agarwal, Miroslav Saraivanov, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

This paper extends the decomposition from the group theory based methods of Sasao and Saraivanov to design binary input multivalued output quantum cascades realized with optical NOT, SWAP, and Fredkin Gates. We present this method for 3, 5, and 7 valued outputs, but in general it can be used for odd prime valued outputs. The method can be extended to realize hybrid functions with different valued outputs. A class of local transformations is presented that can simplify the final cascade circuits. Using these simplifying transformations, we present an upper bound on the maximum number of gates in an arbitrary -variable …


Preserving The Future Of Juries And Jury Trials, Paula Hannaford-Agor, Hope Forbush, Miriam Hamilton, Jawwaad Johnson, Morgan Moffett Dec 2024

Preserving The Future Of Juries And Jury Trials, Paula Hannaford-Agor, Hope Forbush, Miriam Hamilton, Jawwaad Johnson, Morgan Moffett

Faculty Publications

To preserve the future of juries and jury trials, the National Center for State Courts (NCSC) convened a meeting of representatives from a broad array of justice system stakeholders as a project under the Justice for All Reauthorization Act (JFARA). To frame the stakeholder discussions, NCSC employed strategic foresight, a methodological approach designed to explore a range of possible futures of juries and jury trials within the American justice system as a vehicle for identifying critical vulnerabilities within the current jury system and proposing targeted strategies to preserve and strengthen jury trials. Critical vulnerabilities are those areas of weakness that …


Correlates Of Creativity And Elementary School Students’ Perceptions Of Individual And Sociocultural Factors, Seokmin Kang, Hye-Sook Park Dec 2024

Correlates Of Creativity And Elementary School Students’ Perceptions Of Individual And Sociocultural Factors, Seokmin Kang, Hye-Sook Park

Teaching and Learning Faculty Publications

The study investigated the relationships between individual and sociocultural factors and students’ creativity based on a sociocultural perspective. The participants are 7,324 fifth graders from 242 schools obtained from the Korean Educational Longitudinal Study 2013. Through multilevel modeling, student gender, self-regulation behaviors, academic achievement, extrinsic motivation, and perceived parenting style at level 1, and school characteristics such as teacher’s teaching methods, students’ relationship with their teacher, and their teacher’s academic pressure at level 2 were incorporated. The final model incorporating both level 1 and level 2 variables showed that the most significant variable related to students’ creativity was self-regulation, followed …


Higher Abundance Of Disturbance-Favoured Trees And Shrubs In European Temperate Woodlands Prior To The Late-Quaternary Extinction Of Megafauna, Elena A. Pearce, Florence Mazier, Ralph Fyfe, Charles W. Davison, Signe Normand, Maria Antonia Serge, Paolo Scussolini, Jens Christian Svenning Dec 2024

Higher Abundance Of Disturbance-Favoured Trees And Shrubs In European Temperate Woodlands Prior To The Late-Quaternary Extinction Of Megafauna, Elena A. Pearce, Florence Mazier, Ralph Fyfe, Charles W. Davison, Signe Normand, Maria Antonia Serge, Paolo Scussolini, Jens Christian Svenning

School of Geography, Earth and Environmental Sciences

Large herbivorous mammals strongly influence vegetation structure by creating and maintaining open areas and causing disturbance within closed woody habitats. The herbivores alive today in Europe are only a small remnant of the large species that existed in high diversity and abundance before modern humans. The extinction of so many large herbivores during the last 50,000 years, and the loss of megaherbivores (body weight ≥1000 kg) from most of the continent before the Pleistocene–Holocene transition, is likely to have had cascading effects on vegetation structure and composition. To evaluate these effects within the European temperate forest biome, we examine the …


Genetic Analysis Of A Novel Population Of Southern Flying Squirrels (Glaucomys Volans) Found In Lincoln, Ne, Jennifer Wettschreck Dec 2024

Genetic Analysis Of A Novel Population Of Southern Flying Squirrels (Glaucomys Volans) Found In Lincoln, Ne, Jennifer Wettschreck

Biology Theses, Dissertations, and Student Creative Activity

In 2018 a novel population of southern flying squirrels (Glaucomys volans) was discovered in Lincoln, Nebraska, 80 km outside of their known range. Southern flying squirrels are designated as a “Tier-1” species of concern within Nebraska and the origin of this new population is of interest to state biologists. This study will provide insight into the probable origin of this new population by comparing genetic samples from known populations of southern flying squirrels. Museum specimens were collected from two well-established populations in Florida and Texas, as well as samples from individuals native to Nebraska (Indian Cave State Park) to compare …


Investigating The Role Of Feature Integration Demands On Attention Efficiency., Emma Kurtycz Dec 2024

Investigating The Role Of Feature Integration Demands On Attention Efficiency., Emma Kurtycz

College of Arts & Sciences Senior Theses

Feature integration and visual selective attention have been studied together to understand how we attend to different objects, often through conjunction search tasks. Conjunction search tasks involve searching for an object defined by multiple visual features in the presence of distractors. However, few studies have examined how different visual feature combinations impact search performance. Motivated by the functional and structural organization of the brain, this study investigated how differing feature combinations that theoretically place varying degrees of demand on feature integration impact attention efficiency. In two experiments, I explored reaction times (RT) and target detection sensitivity (d’) across varying set …


New Approaches And Challenges Regarding Trade, Climate Action, And The Wto, Sunayana Sasmal Dec 2024

New Approaches And Challenges Regarding Trade, Climate Action, And The Wto, Sunayana Sasmal

Columbia Center on Sustainable Investment

This report considers how the WTO, as an institution and its rules, can and should be a game-changer in undertaking climate action and the green energy transition globally. By leveraging its toolkit, the WTO has the potential to drive climate action, from regulating border carbon adjustments to promoting trade in green products, green electricity, and dissemination of climate technologies. However, unlocking this potential requires legal reforms, a proactive institutional role, and strong political will from WTO members.


Effects Of Parent Involvement In Academic Achievement Of Upper Elementary School Student, Joseph Guzman Dec 2024

Effects Of Parent Involvement In Academic Achievement Of Upper Elementary School Student, Joseph Guzman

Capstone Projects and Master's Theses

This senior capstone research project focuses on how parental involvement can affect academic achievement in upper elementary school students. Understanding the various factors of parental involvement is crucial to gaining insight into its impact on students, parents, teachers, and principals. Through the use of literature review, interviews with four teachers, one principal, and anonymous surveys of one classroom of 26 fourth-grade students, the result findings indicated that parental involvement is a vital component of students' academics and is essential for their positive progress. Effective communication among teachers, principals, and parents regarding class and schoolwork significantly impacts students' academic achievement. In …


Enhancing Memory Through Literary Features, Sarah Naylor Dec 2024

Enhancing Memory Through Literary Features, Sarah Naylor

Psychological Science Undergraduate Honors Theses

Literary devices used by a writer can influence and impact the manner in which readers respond and interact with a text. Both the perspectives readers are expected to take while reading and the amount of foregrounding in a text cognitively and affectively influence a reader’s experience. However, little research has explored what effects these factors have on verbatim memory. For this research, participants were instructed to read a short literary story either by identifying with the protagonist or as a spectator. After reading and completing a range of other tasks, participants were asked to select sentences they saw in the …


The Elusive Nature Of Martian Liquid Brines, Vincent F. Chevrier, Rachel A. Slank Dec 2024

The Elusive Nature Of Martian Liquid Brines, Vincent F. Chevrier, Rachel A. Slank

Space and Planetary Science Faculty Publications and Presentations

The possible presence of brines on Mars adds an intriguing dimension to the exploration of Martian environments. Their potential involvement in the formation of recurring slope lineae has sparked debates on the existence of liquid water versus alternative dry processes. In situ instrumentation on rovers and landers has been instrumental in providing valuable data for comprehending the dynamics of brines. Laboratory experiments and thermodynamic simulations conducted under Martian conditions offer insights into the formation and persistence of brines, shedding light on the planet’s current hydrological processes. Despite these findings, the prevailing surface conditions on Mars, characterized by a combination of …


Verification Of Past Beliefs Influences Current Beliefs, Michael Wolfe, Todd Williams, Alexander J. Denison, Liam W. Hart Dec 2024

Verification Of Past Beliefs Influences Current Beliefs, Michael Wolfe, Todd Williams, Alexander J. Denison, Liam W. Hart

Open Access Publishing Support Funded Articles

Background: It is important to understand the factors that influence belief formation and belief change.

Objective: We test the hypothesis that following belief change about contentious topics, verifying a past belief will influence current beliefs.

Methods: In Experiment 1, participants reported initial beliefs about television violence in a prescreening, then read a belief-inconsistent text in the experiment. Participants either verified or did not verify their initial beliefs before reporting current beliefs. In Experiment 2, participants were randomly assigned to verify their initial belief (about gun control effectiveness), a false belief that was the opposite of their initial belief or did …


Primary Industries Education Foundation Australia (Piefa) Storm And Flood Industry Recovery Program: Evaluation Report, Tamara Van Der Zant, Katherine Dix Dec 2024

Primary Industries Education Foundation Australia (Piefa) Storm And Flood Industry Recovery Program: Evaluation Report, Tamara Van Der Zant, Katherine Dix

Program monitoring and evaluation

Despite the growing diversity of careers in Primary Industries, young peoples’ pursuit of agricultural careers is often hampered by outdated perceptions of the sector and its opportunities. As Primary Industries adapt to the threat of natural disasters by turning to scientific and technological solutions, a diverse, highly skilled workforce will be required. In the wake of the devastating impacts of storm and floods in early 2021 across New South Wales, the Storm and Flood Industry Recovery Program (SFIRP): Creating resilience through empowering school curriculums about primary industries careers project was developed. To aid the long-term recovery and resilience of the …


Relative Muscular Effort In The Older Adults During The Sit-To-Stand Task: Monitoring Neuromuscular Reserve And Movement Limitations, Nayun Ahn, Michael H. Haischer, Cara L. Lewis, Kristof Kipp Dec 2024

Relative Muscular Effort In The Older Adults During The Sit-To-Stand Task: Monitoring Neuromuscular Reserve And Movement Limitations, Nayun Ahn, Michael H. Haischer, Cara L. Lewis, Kristof Kipp

Exercise Science Faculty Research and Publications

Background

Due to lower maximum strength, older adults purportedly need to exert greater muscular effort to stand up from a chair. This study investigated joint-specific muscular effort during a sit-to-stand by calculating relative-muscular-effort and investigating differences between healthy older and young adults.

Methods

Fifteen older (age: 69.9 ± 3.5 years) and 15 young (age: 22.2 ± 2.6 years) adults performed five self-paced sit-to-stand trials. Kinematic and kinetic data were collected and used to calculate inverse dynamics net joint moment. Peak isometric knee and hip extensor torques were measured and used as inputs to regression models that predicted angle- and velocity-dependent …


Steering Research On Mrna Splicing In Cancer Towards Clinical Translation, Olga Anczukow, Frédéric H-T Allain, Brittany L Angarola, Douglas L Black, Angela N Brooks, Chonghui Cheng, Ana Conesa, Edie I Crosse, Eduardo Eyras, Ernesto Guccione, Sydney X Lu, Karla M Neugebauer, Priyanka Sehgal, Xiao Song, Zuzana Tothova, Juan Valcárcel, Kevin M Weeks, Gene W Yeo, Andrei Thomas-Tikhonenko Dec 2024

Steering Research On Mrna Splicing In Cancer Towards Clinical Translation, Olga Anczukow, Frédéric H-T Allain, Brittany L Angarola, Douglas L Black, Angela N Brooks, Chonghui Cheng, Ana Conesa, Edie I Crosse, Eduardo Eyras, Ernesto Guccione, Sydney X Lu, Karla M Neugebauer, Priyanka Sehgal, Xiao Song, Zuzana Tothova, Juan Valcárcel, Kevin M Weeks, Gene W Yeo, Andrei Thomas-Tikhonenko

Faculty, Staff and Students Publications

Splicing factors are affected by recurrent somatic mutations and copy number variations in several types of haematologic and solid malignancies, which is often seen as prima facie evidence that splicing aberrations can drive cancer initiation and progression. However, numerous spliceosome components also 'moonlight' in DNA repair and other cellular processes, making their precise role in cancer difficult to pinpoint. Still, few would deny that dysregulated mRNA splicing is a pervasive feature of most cancers. Correctly interpreting these molecular fingerprints can reveal novel tumour vulnerabilities and untapped therapeutic opportunities. Yet multiple technological challenges, lingering misconceptions, and outstanding questions hinder clinical translation. …


Supervenience And Non-Naturalism, Michael Hogan Dec 2024

Supervenience And Non-Naturalism, Michael Hogan

Graduate Theses and Dissertations

Supervenience presents a problem for the moral non-naturalist. Supervenience states that one’s moral properties cannot differ without one’s natural properties differing. It, therefore, states a necessary connection between moral and natural properties. Moral properties for the moral non-naturalist are sui generis, which means they are not reducible to natural properties, but also they are utterly different in kind than natural properties and any other kind of property. How can these properties be necessarily connected? This requires an explanation. The challenge to the moral non-naturalist is to provide such an explanation. McPherson (2012) presents an explanatory challenge to the non-naturalist …


Design And Fabrication Of Graphene Solar Cells For Low-Power Energy Harvesting Systems, Tamzeed Bani Amin Dec 2024

Design And Fabrication Of Graphene Solar Cells For Low-Power Energy Harvesting Systems, Tamzeed Bani Amin

Graduate Theses and Dissertations

This study presents the design and fabrication of graphene-based Schottky junction solar cells integrated into a 3-volt power system for low-power applications. Utilizing standard semiconductor processing methods, including selective oxide removal, metal contact deposition, and large-area graphene transfer, we fabricated solar cells from a silicon wafer coated with a thermal oxide layer. Each individual solar cell generated up to 270 µA of short-circuit current and an open-circuit voltage of 420 mV under illumination. We connected multiple solar cells in series to produce a total output of 3.3 volts, which is sufficient to recharge a 3-volt battery. The system, comprising these …


A Cmos Ldo Voltage Regulator For Low Power Applications, Nicolaus Vail Dec 2024

A Cmos Ldo Voltage Regulator For Low Power Applications, Nicolaus Vail

Graduate Theses and Dissertations

This thesis presents the design, simulation, layout, and testing of a low dropout linear voltage regulator (LDO) in a 180 nm CMOS process. The LDO is intended for use in low-power, battery-operated applications, and it has an adjustable output for a variety of different implementations. It can supply up to 100 mA of current, which is enough to power many small electronic circuits. It has a dropout voltage of 150 mV, and it consumes less than 200 μA of current during operation, which is on par with many commercial regulators. The line regulation is also comparable to commercially available LDOs, …


The Bander Portal Dats Submission Module, Lauren Walker, Matthew Rogosky, Kyra Harvey Dec 2024

The Bander Portal Dats Submission Module, Lauren Walker, Matthew Rogosky, Kyra Harvey

North American Bird Bander

No abstract provided.


Use Of Hatchery-Raised Fish In Validation Of Daily Age Estimates For Juvenile Common Snook, Philip W. Stevens, Kyle L. Williams, Meredith B. Pfennig, Ryan W. Schloesser, Alexis A. Trotter, Derek P. Crane Dec 2024

Use Of Hatchery-Raised Fish In Validation Of Daily Age Estimates For Juvenile Common Snook, Philip W. Stevens, Kyle L. Williams, Meredith B. Pfennig, Ryan W. Schloesser, Alexis A. Trotter, Derek P. Crane

Biology

Objective: We investigated the validity of daily age estimates for juvenile Common Snook Centropomus undecimalis by using sectioned and sanded sagittal otoliths. Methods: Common Snook have a protracted spawning season, which is problematic for validation of daily ages because a hatch date—needed to calculate age—cannot be reasonably assigned like it can for species with a short spawning period (<30 days). To help overcome this, two readers independently counted presumed daily increments in otoliths collected from hatchery-reared Common Snook of known age (100–240 days; n = 91). Result: Differences between known ages and those estimated from otoliths were small (mean absolute difference = 3.4 days) for individuals aged 100 days, but these differences increased after 100 days, mainly due to the crowding of increments along the otolith margin. Underestimation of ages was 8% at 120 days, 29% at 180 days, and 36% at 240 days. Conclusion: Ideally, analyses based on counts of daily increments in Common Snook otoliths should be limited to fish with an age of 100 days or younger.