Digital Commons Network^™

Test-Retest Apparent Diffusion Coefficient Reproducibility In Head And Neck Cancer Using A 15-T Mr-Linac, Brigid A Mcdonald, Dina El-Habashy, Renjie He, Sam Mulder, Sarah Mirbahaeddin, Abdallah S R Mohamed, Sara Ahmed, Yao Ding, Jihong Wang, Stephen Y Lai, Alex Dresner, John Christodouleas, Clifton D Fuller

Faculty, Staff and Student Publications

Purpose

To evaluate the reproducibility of apparent diffusion coefficient (ADC) measurements in head and neck squamous cell carcinoma (HNSCC) using a 1.5-T MR-linac (MRI-guided linear accelerator) system.

Materials and Methods

In this retrospective study, conducted between February 2021 and January 2024, patients with HNSCC lesions underwent echo-planar imaging diffusion-weighted MRI on a 1.5-T MR-linac system at two time points before the start of radiation therapy. Mean and median ADC values and volumes were measured for each lesion. Absolute and percent reproducibility coefficients (RCs) were calculated. Linear regression analyses and F tests were performed to determine whether the lesion volume or …

Cerebellar Motor And Non-Motor Contributions To Dystonia Pathophysiology And Treatment, Linda H Kim, Cheryl Brandenburg, Roy V Sillitoe

Duncan NRI Faculty and Staff Publications

Dystonia is a complex neurological disorder characterized by sustained or intermittent abnormal movements and/or postures. However, dystonia's non-motor symptoms, particularly the sleep disturbances, are critical yet underexplored concerns that affect all ages. Here, we synthesize current knowledge on the motor and non-motor domains of dystonia, emphasizing the functional interconnections and plasticity within cerebellar motor, cognitive, and sleep-associated circuits to motivate more comprehensive and effective treatments that improve overall quality of life.

Organ Chips And Translational Research: Identifying And Examining New Ethical Issues, Melanie Jeske

Center for Medical Ethics and Health Policy Staff Publications

Organ chips, also known as organ-on-a-chip devices, tissue chips, or microphysiological systems, have emerged over the last decade as a promising translational technology amidst growing concern about the translational crisis between laboratory research and patient bedside. Pointing to high rates of failure between nonhuman animal models and safety and efficacy in humans, organ chips and similar new approach methods have attracted substantial public and private investment. As human-cell-based alternatives to animal models, organ chips promise more predictive, efficient, and ethical platforms for pharmaceutical and toxicity testing. Engineered cultivation systems that enable cells to assemble into tissue-like structures (e.g. kidney, brain, …

Anything But Endo: Diagnostic Buck-Passing In Endometriosis Diagnosis, Rita Dexter, Megan Kitts, Heather Welty, Melanie Jeske

Center for Medical Ethics and Health Policy Staff Publications

People living with endometriosis, a disease in which tissue similar to the lining of the uterus grows elsewhere in the body, often experience prolonged diagnostic journeys because of symptom variability, normalisation of period pain and other symptoms, and lack of awareness of the condition. In this article, we analyse the endometriosis diagnostic journey through the lens of epistemic injustice. Drawing on in-depth interviews with 52 people living with endometriosis in the United States, we introduce the concept of diagnostic buck-passing to characterise the phenomenon wherein individuals who seek treatment for their symptoms end up stuck in a cycle of seeing …

Access To Digital Health Technologies: Personalized Framework And Global Perspectives, Sanjiv M Narayan, Mina K Chung, Demilade Adedinsewo, Luisa C C Brant, Leslie L Davis, David Duncker, Jennifer L Hall, Janet K Han, Carolyn S P Lam, Eldrin Lewis, Joseph Loscalzo, Manlio F Márquez, Vasiliki Rahimzadeh, Fatima Rodriguez, Prashanthan Sanders, Emma Svennberg, Kenneth Stein, Mintu Turakhia, Clyde Yancy, Antonis A Armoundas

Center for Medical Ethics and Health Policy Staff Publications

The emergence and rapid adoption of digital health technologies (DHT) present unprecedented opportunities to democratize and reduce disparities in health care by monitoring health and disease at the point of care in all patients. However, limited access to DHT is becoming a major obstacle to realizing these goals. Access to DHT is influenced not only by well-recognized social determinants of health, but also by digital determinants of health, such as digital literacy and the need for broad access to digital infrastructure, as well as commercial and economic factors. Addressing these challenges and designing unbiased systems of care are essential to …

Toward Ethical Provenance Tracking: The Ga4gh Model Data Access Agreement (Daa), Alexander Bernier, Bartha Maria Knoppers, Jonathan Lawson, Robyn Mcdougall, Maili Raven-Adams, Vasiliki Rahimzadeh

Center for Medical Ethics and Health Policy Staff Publications

Purpose: Standardizing contractual clauses that govern data access enables research institutions to responsibly steward genomic and related health data while enabling its efficient downstream reuse.

Methods: We describe a document analysis study using both qualitative and comparative law analytical approaches to identify the most common categories of clauses from 29 different data access agreements used by human biomedical research consortia globally. We furthermore characterized the legal positions and standard practices for each common element of the agreement and synthesized across them to develop model clauses. A total of 3 discussion sessions were organized virtually to refine the clauses among members …

Psychometric Properties Of A Novel Affective Bias Task And Its Application In Clinical And Nonclinical Populations, Prathik Kalva, Kourtney Kanja, Brian A Metzger, Xiaoxu Fan, Brian Cui, Bailey Pascuzzi, John Magnotti, Madaline Mocchi, Raissa Mathura, Kelly R Bijanki

Faculty, Staff and Students Publications

To mitigate limitations in self-reported mood assessments, we introduce a novel affective bias task (ABT). The task quantifies instantaneous emotional state by leveraging the phenomenon of affective bias, in which people interpret external emotional stimuli in a manner consistent with their current emotional state. This study establishes task stability in measuring and tracking depressive symptoms in clinical and non-clinical populations. Initial assessment in a large non-clinical sample established normative ratings. Depressive symptoms were tracked relative to task performance in a non-clinical sample, as well as in a clinical cohort undergoing surgical evaluation for severe epilepsy. In both cohorts, a stronger …

Tau In Alzheimer’S Disease: Shaping The Future Patient Journey, Catherine J Mummery, Christopher Chen Li-Hsian, Cristian A Lasagna-Reeves, Rik Ossenkoppele, Christopher C Rowe, Douglas W Scharre, Huali Wang, Simon Kyaga, Jeffrey L Cummings

Faculty, Staff and Students Publications

Alzheimer's disease is a complex and multifactorial disease characterized by two key pathological hallmarks: amyloid-beta plaques and tau neurofibrillary tangles. Recent progress has led to the development and approval of disease-targeted therapies for Alzheimer's disease in the form of anti-amyloid-beta monoclonal antibodies. However, findings suggest that amelioration of multiple pathological drivers may be required to maximize clinical effect. An increasing body of evidence suggests that tau is a critical player in Alzheimer's disease pathophysiology, contributing significantly to neurodegeneration and cognitive decline. There are now several tau-targeting drugs in clinical development. In this review, we build on research and advancements in …

Senolytic-Resistant Senescent Cells Have A Distinct Sasp Profile And Functional Impact: The Path To Developing Senosensitizers, Utkarsh Tripathi, Masayoshi Suda, Vagisha Kulshreshtha, Bryan T Piatkowski, Allyson K Palmer, Nino Giorgadze, Christina Inman, Nathan Gasek, Ming Xu, Kurt O Johnson, Tamar Pirtskhalava, Selim Chaib, Larissa P G Langhi Prata, Yi Zhu, Renuka Kandhaya-Pillai, Stefan G Tullius, Saranya P Wyles, Rambabu Majji, Hari Krishna Yalamanchili, David B Allison, Tamar Tchkonia, James L Kirkland

Faculty, Staff and Students Publications

The senescent cell (SC) fate is linked to aging, multiple disorders and diseases, and physical dysfunction. Senolytics, agents that selectively eliminate 30%-70% of SCs, act by transiently disabling the senescent cell antiapoptotic pathways (SCAPs), which defend those SCs that are proapoptotic and pro-inflammatory from their own senescence-associated secretory phenotype (SASP). Consistent with this, a JAK/STAT inhibitor, Ruxolitinib, which attenuates the pro-inflammatory SASP of senescent human preadipocytes, caused them to become "senolytic-resistant". Administering senolytics to obese mice selectively decreased the abundance of the subset of SCs that is pro-inflammatory. In cell cultures, the 30%-70% of human senescent preadipocytes or human umbilical …

Correction: Establishing Standardized Transthoracic Echocardiography Reference Ranges For Mouse Models: Insights Into The Impact Of Anesthesia, Sex, And Age, Manuela A Oestereicher, Christopher S Ward, Elida Schneltzer, Susan Marschall, Helmut Fuchs, Valerie Gailus-Durner, Ghina Bou About, Mohammed Selloum, Hamid Meziane, Michelle Stewart, Lydia Teboul, Clare Norris, Dale Pimm, Marina Kan, Federico López Gómez, Robert Wilson, Mayra Monroy, Sheraz Pasha, Eva Zabrodska, Jan Prochazka, David Pajuelo Reguera, Zuzana Nichtova, Yann Herault, Sara Wells, Helen Parkinson, Jason D Heaney, Radislav Sedlacek, Xiang Gao, Martin Hrabe De Angelis, Nadine Spielmann

Faculty, Staff and Students Publications

This corrects the article "Establishing standardized transthoracic echocardiography reference ranges for mouse models: insights into the impact of anesthesia, sex, and age" in volume 12, 1695034.

Case Series Of Nizon-Isidor Syndrome By Heterozygous Variants In Med12l With Further Evidence Of Mitotic Instability In One Case With Diploid-Triploid Mosaicism, Russell Stewart, Kimberly M Ezell, Deanna S Bell, Brian Corner, Ashley Mcminn, Joy D Cogan, Rizwan Hamid, Lynette Rives, John A Phillips, Nina Paddu, Gitanjali Srivastava, Ronit Marom, Farah A Ladha, Claudia Soler-Alfonso, Rachel Franciskovich, Mary Koziura, Sumit Pruthi, Gabriele Richard, Christina B Sheedy, Undiagnosed Diseases Network, Thomas Cassini

Faculty, Staff and Students Publications

Nizon-Isidor syndrome is a rare disorder caused by heterozygous variants in MED12L, with only eight documented cases in the literature. Here, we present three additional cases of this syndrome. Proband 1 was a 7-year-old female who presented with developmental delay, right-leg hemihypertrophy, laryngeal cleft, esotropia, abnormal skin pigmentation, sectoral iris hypopigmentation, dysphagia, periventricular nodular heterotopia, seizures, morbid obesity, and a pelvic kidney. Genome sequencing (GS) revealed a MED12L variant, NM_053002.5:c.3559+2T>G. Both computational models and transcriptomic analysis confirmed that this variant induced splice loss of MED12L exon 25. Probands 2 and 3 presented with overlapping phenotypes of developmental delay; sequencing …

Efficacy And Safety Of Pyrimidine Nucleos(T)Ide Therapy In Thymidine Kinase 2 Deficiency, Michio Hirano, Caterina Garone, Richard Haas, Carmen Paradas, Fernando Scaglia, Irene Rebollo Mesa, Carl Chiang, Anny-Odile Colson, Susan Vanmeter, Cristina Domínguez-González

Faculty, Staff and Students Publications

Thymidine kinase 2 deficiency (TK2d) (MIM 609560) is an ultra-rare, autosomal recessive mitochondrial myopathy caused by TK2 variants, leading to mitochondrial DNA depletion and/or multiple deletions. People with thymidine kinase 2 deficiency experience progressive myopathy, bulbar weakness and respiratory insufficiency, often losing the ability to walk, eat and breathe independently. Doxecitine and doxribtimine represents the first approved treatment for patients with thymidine kinase 2 deficiency with age of symptom onset ≤12 years by the US Food and Drug Administration and the European Medicines Agency; previously, disease management was limited to supportive care. We investigated the efficacy and safety of pyrimidine …

Rare But Relevant? Assessing Variants In Dystonia-Linked Genes In Parkinson's Disease, Lara M Lange, Zih-Hua Fang, Laurel Screven, Ai Huey Tan, Roy N Alcalay, Rim Amouri, Roberta Bovenzi, Matilda Fenn, Joshua L I Frost, Joseph Jankovic, Simona Jasaityte, Zane Jaunmuktane, Beomseok Jeon, Ignacio Juan Keller Sarmiento, Rejko Krüger, Gregor Kuhlenbäumer, Chin-Hsien Lin, Lukas Pavelka, Maria Teresa Periñan, Samia Ben Sassi, Tommaso Schirinzi, Jung Hwan Shin, Joshua M Shulman, Yi Wen Tay, Ryan Uitti, Tom Warner, Zbigniew K Wszolek, Lesley Wu, Ruey-Meei Wu, Kirsten E Zeuner, Cornelis Blauwendraat, Andrew Singleton, Niccolò E Mencacci, Huw R Morris, Shen-Yang Lim, Katja Lohmann, Christine Klein

Faculty, Staff and Students Publications

Background: Dystonia and Parkinson's disease (PD) exhibit clinical and genetic overlap, but the relevance of dystonia gene variants in PD remains unclear.

Objective: The aim was to assess the frequency of dystonia-linked pathogenic variants in PD.

Methods: We screened sequencing data from 15,684 individuals (8272 PD, 3200 atypical parkinsonism, and 4212 unaffected) from the Global Parkinson's Genetics Program (GP2) and Accelerating Medicines Partnership-Parkinson's Disease (AMP-PD) for variants in genes linked to isolated dystonia, dystonia-parkinsonism, and myoclonus-dystonia.

Results: Pathogenic variants were identified only in PD patients. Forty-five PD individuals (0.54%) carried 26 distinct (likely) pathogenic variants in nine dystonia-linked genes, most …

The Words Community Dwelling, Spanish-Preferring Mexican/Mexican American Adults Use To Talk About Alzheimer’S Disease And Genetic Testing: Implications For Education And Outreach, Jamie C Fong, Fatima I Chavez, Karla Silos, Mirna L Arroyo-Miranda, Gabriela Castro Castro, Mark E Kunik, Joshua M Shulman, Luis D Medina

Faculty, Staff and Students Publications

Introduction: Hispanic/Latino (H/L) adults are more likely than non-Hispanic White individuals to have Alzheimer's disease (AD), yet fewer than one in five H/L adults has apolipoprotein E (APOE) Ɛ4, underscoring gaps in understanding genetic risk across H/L heritage groups. H/L adults remain underrepresented in AD research that uses genetic data for participant stratification. To inform culturally appropriate educational materials for 16 million U.S. Spanish speakers, we identified culturally salient words Spanish-preferring H/L adults use to describe AD and genetic testing beyond APOE.

Methods: Community-residing, Spanish-preferring Mexican/Mexican American adults (n = 14) completed freelisting interviews, a method eliciting …

Highly Variable Expressivity Of A Cnv Deletion Involving Tbx4 In Three Deceased Siblings With Lung Developmental Disorder And Their Mildly Affected Mother And Grandfather, Przemyslaw Szafranski, Tomasz Gambin, Michal Kadlof, Michał Denkiewicz, Dariusz Plewczynski, Hyun Jeong Kim, Gail Deutsch, Nahir Cortes-Santiago, Salmo Raskin, Paweł Stankiewicz

Faculty, Staff and Students Publications

Single nucleotide variants (SNVs) and copy-number variant (CNV) deletions involving TBX4 have been associated with pulmonary arterial hypertension, ischiocoxopodopatellar syndrome, and lethal lung developmental disorders (LLDDs). Thus far, all large CNV deletions encompassing entire TBX4 have been found to have arisen de novo. Here, we present a three-generation family with three neonate siblings who died within 35-66 days due to histopathologically diagnosed LLDD. Whole-genome sequencing identified an ~108-kb CNV deletion encompassing TBX4 in all three infants. The deletion was also found in their mother with a history of pneumonia and persistent thick upper airway secretions and in the maternal grandfather …

Transition To Tenecteplase Is Associated With Shorter Door-To-Puncture Times: A Retrospective Study From The Lone Star Stroke Consortium Tnk Registry, Anqi Luo, Sujani Bandela, Gretchel Gealogo-Brown, Mark P Goldberg, Andrew Slusher, Reza Behrouz, Alibay Jafarli, Siddarth Prasad, Daiwai Olson, Maria Denbow, Mehari Gebreyohanns, Asmiet Techan, Chethan P Venkatasubba Rao, Jane A Anderson, Barbara Kimmel, Anette Ovalle, Michele Patterson, Sean I Savitz, Salvador Cruz-Flores, Steven Warach, Lee Birnbaum

Faculty, Staff and Students Publications

Background: Intravenous thrombolytic (IVT) and mechanical thrombectomy (MT) therapies are the current standard of care for large vessel occlusion (LVO) stroke. Multiple studies emphasized the impact of time metrics on patient outcomes, particularly door-to-needle (DTN) and door-to-puncture (DTP) times. Tenecteplase (TNK) offers potential advantages over alteplase (ALT), including a simplified one-time bolus administration, which may reduce DTP time. Results suggest TNK is non-inferior to ALT in terms of clinical outcomes, but few large cohort studies have compared DTP time for patients receiving TNK vs. ALT prior to thrombectomy. This real-world study aimed to compare DTP times and discharge outcomes in …

Proceedings Of The 13th Annual Deep Brain Stimulation Think Tank: The Evolving Landscape, Chance R Fleeting, Eduardo M Moraud, Kamil Uğurbil, Doris D Wang, Wolf-Julian Neumann, Andrea A Kühn, Valerie Voon, Victor Pikov, Marie-Laure Welter, Michael D Fox, John D Rolston, Mahsa Malekmohammadi, Yagna J Pathak, Lyndahl M Himes, David Greene, Abbey S Holt-Becker, Gabriel Lázaro-Muñoz, Alexander W Charney, Amanda R Merner, Martijn Figee, Katherine W Scangos, Timothy Denison, Kent Leyde, Aysegul Gunduz, Helen M Bronte-Stewart, James C Beck, Nora Vanegas-Arroyave, Marta San Luciano, Norbert Brüggemann, Kelly D Foote, Michael S Okun, Joshua K Wong

Faculty, Staff and Students Publications

The Deep Brain Stimulation (DBS) Think Tank XIII was held September 2-4th, 2025, in Gainesville, Florida, at the Norman Fixel Institute for Neurological Diseases at the University of Florida. The theme was "The Evolving Landscape of DBS: New Indications, New Goals." This theme was a continuation of the DBS Think Tank XI and XII, which were focused on emerging technology and pushing the horizon of indications. Since its founding in 2012, the DBS Think Tank has provided a global forum for leading clinicians, engineers, and researchers in both in industry and academia to present, discuss, and debate the current state …

Transient Disruption Of Bladder Control Linked To Periaqueductal Gray Fibers Following Deep Brain Stimulation For Psychiatric Disorders, Thomas Hamre, Hideo Suzuki, Sarah Soubra, Reem El Jammal, Melissa A Ryan, Sanjay J Mathew, Jeffrey A Herron, Nidal Moukaddam, Eric A Storch, Nora Vanegas Arroyave, Kara L Marshall, Garrett P Banks, Nader Pouratian, Wayne K Goodman, Nicole R Provenza, Sameer A Sheth, Sarah R Heilbronner

Faculty, Staff and Students Publications

No abstract provided.

Validation Of The Norwegian Version Of The Movement Disorder Society-Unified Parkinson's Disease Rating Scale, Guido Alves, Yvonne Stavland Sørenes, Veslemøy Hamre Frantzen, Michaela Dreetz Gjerstad, Anders Ledaal Bjørnestad, Jodi Maple-Grødem, Elin Bjelland Forsaa, Ylva Hivand Hiorth, Karen Herlofson, Espen Benjaminsen, Kari Anne Bjørnarå, Espen Dietrichs, Roberta Balestrino, Carmen Gasca-Salas, Chi-Ying R Lin, Alvaro Sanchez-Ferro, Michelle H S Tosin, Tiago A Mestre, Monica M Kurtis, Pablo Martinez-Martin, Sheng Luo, Luowen Yu, Glenn T Stebbins, Christopher G Goetz, Mds Coa Translation Steering Committee

Faculty, Staff and Students Publications

Introduction: The Movement Disorder Society-revised version of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is the gold standard assessment for evaluating Parkinson's disease (PD) symptoms and severity, but a validated Norwegian version is not yet available. We translated the original English MDS-UPDRS into Norwegian and tested the clinimetrics of the translated version following the MDS-established protocol for non-English language translations.

Methods: Two independent teams translated the English version of the MDS-UPDRS into Norwegian. After review of the back-translated English version, cognitive pretesting was performed in twelve PD patients at one study site. This was followed by large-scale testing completed by …

Case Report: Molecular Diagnostics And Clinical Courses Of Two Adult Spinal Pilocytic Astrocytoma Long-Term Survivors With Gtf2i::Braf Fusion, Lorenzo Argao, Pinar E Zerk, Hsiang-Chih Lu, Zied Abdullaev, Martha Quezado, Michelle L Cassidy, Bennett Mclver, Anna Choi, Marissa Panzer, Renee Tweneboah-Koduah, Lily Polskin, Marta Penas-Prado, Paul Park, Nathan Clarke, Kenneth Aldape, Jacob Mandel, Byram H Ozer

Faculty, Staff and Students Publications

Introduction: Pilocytic astrocytomas are driven by BRAF and mitogen-activated protein kinase (MAPK) alterations, typically KIAA1549::BRAF fusions. A rare GTF2I::BRAF fusion has been described, but little is known about these cases.

Case report: Here, we report two cases with GTF2I::BRAF fusions. Case 1 is a 36-year-old man initially diagnosed with myxopapillary ependymoma at the conus medullaris with three recurrences over 23 years requiring two surgeries, three rounds of radiation therapy, and one round of lapatinib/temozolomide. A distant disease focus in T3/T4 was sampled and tested with modern diagnostic techniques revealing a pilocytic astrocytoma on histology and methylation profiling. The patient has …

Suicidal Ideation In Spinocerebellar Ataxia, Levi Peppel, Ruo-Yah Lai, Christian Rummey, Puneet Opal, Jeremy D Schmahmann, Christopher M Gomez, Henry Paulson, Theresa A Zesiewicz, Susan Perlman, George Wilmot, Sarah H Ying, Chiadi U Onyike, Khalaf O Bushara, Michael D Geschwind, Karla P Figueroa, Stefan M Pulst, Sub H Subramony, Antoine Duquette, Tetsuo Ashizawa, Ali G Hamedani, Marie Y Davis, Sharan R Srinivasan, Matthew R Burns, Nadia Amokrane, Lauren R Moore, Vikram G Shakkottai, Liana S Rosenthal, Sheng-Han Kuo, Chi-Ying R Lin

Faculty, Staff and Students Publications

Objective: Suicidal ideation has not been extensively studied in spinocerebellar ataxias (SCAs). The authors examined whether individuals with SCAs have increased suicidal ideation and related factors.

Methods: The authors studied patients with genetically confirmed SCAs enrolled in the Clinical Research Consortium for the Study of Cerebellar Ataxia cohort, examining the percentages of patients with SCA subtypes 1, 2, 3, and 6 who reported suicidal ideation and comparing findings with nationally representative data from the National Survey on Drug Use and Health (NSDUH). Clinical characteristics that may contribute to suicidal ideation in SCAs, including age, disease duration, sex, ataxia severity, depression, …

Age-Related Variations Of The Hemodynamic Response Function Spatially Resolved Across Human Cerebral Cortex, Nooshin J Fesharaki, Amanda Taylor, David Ress

Faculty, Staff and Students Publications

Normal aging leads to regional vascular and neural alterations. Age-related impairments in neurovascular coupling (NVC) affect the blood-oxygen-level-dependent (BOLD) hemodynamic response function (HRF) measured with functional magnetic resonance imaging, causing changes in both amplitude and temporal dynamics. Previously, global, systematic age-related changes in HRF characteristics were demonstrated, consistent with known microvascular aging effects. In this follow-up study, a standard space was used to compare spatially resolved cortical HRF dynamics between sex-balanced groups of young and older adults. The results showed substantial age-related differences in both HRF amplitude and timing across distinct cortical regions. Nearly twice as much cortical area exhibited …

Pathos, Winter 2026, Portland State University. Student Publications Board

Pathos

Editor: Adriana Stanzione

Density Dependence During Evolutionary Rescue Increases Extinction Risk But Does Not Prevent Adaptation, Laure Olazcuaga, Brett A. Melbourne, Scott W. Nordstrom, Ruth A. Hufbauer

Publications, Reports and Presentations

Evolutionary rescue allows populations to adapt and persist despite severe environmental change. While well studied under density-independent conditions, the role of density dependence, including competition, remains unclear. Theoretical models offer conflicting predictions, with density dependence either increasing extinction risk or enhancing adaptation. We empirically tested how density dependence influences evolutionary rescue by exposing experimental populations to a stressful environment for six generations under density-dependent or independent conditions, with populations where either evolution was possible or was prevented by replacing individuals each generation. Density dependence suppressed population size and increased extinction risk, whereas density independence enabled rapid growth, especially in genetically …

Geographic Variation In Proteomic Responses To Ocean Acidification In A Cold-Water Coral (Balanophyllia Elegans), Keana A. Richmond

Cal Poly Humboldt theses and projects

In the face of a rapidly changing climate, assessing organismal responses to future stressors in the context of current, natural exposure to stress could provide key insights to understanding marine ecosystem resilience. I used Balanophyllia elegans, a cold-water, solitary, azooxanthellate coral as a model to better understand how varying oceanographic conditions across its geographic range have shaped its ability to tolerate and potentially adapt to current and future ocean acidification conditions. I collected B. elegans individuals from four sites across 2,500km of their range and subjected them to two pH treatments to investigate site-specific protein expression in response to …

Early Successional Response To Stream Daylighting In Redwood National And State Parks, Orick, California, Rylee Rawson

Cal Poly Humboldt theses and projects

In-channel stream restoration projects can act as both disturbance and recovery mechanisms, disrupting existing conditions to reestablish the hydrologic and ecological processes that sustain stream ecosystems. These interventions initiate successional trajectories in which channel form and biological communities reorganize over time. In Redwood National and State Parks (California, USA), the Redwoods Rising initiative restores buried headwater channels by recontouring legacy logging roads and daylighting streams buried by Humboldt crossings. Using the National Park Service Klamath Network wadable stream monitoring protocol, I evaluated nine restored reaches spanning one to five years post-restoration, alongside old-growth reference reaches and available pre-treatment data. I …

Coho Salmon (Oncorhynchus Kisutch) Response To Habitat Restoration Through Space And Time: Monitoring Growth, Survival, And Movement In A Restored Habitat Network, Carter Perez Adamson

Cal Poly Humboldt theses and projects

Despite the decline of coho salmon (Oncorhynchus kisutch), Prairie Creek, a tributary of Redwood Creek in northern California, remains a coho salmon stronghold. The restoration of juvenile coho rearing habitat was identified as a recovery objective in this watershed by the National Marine Fisheries Service. Among the restoration projects addressing this objective are an ongoing project on Prairie Creek and its tributary Skunk Cabbage Creek, and a prior effort on Strawberry Creek (a tributary of Redwood Creek’s estuary). Standard monitoring methods for assessing project success have limitations and may be improved by measuring salmon use of restored habitats …

Postfire Habitat Use And Density Of Pacific Martens (Martes Caurina) In Lassen National Forest, California, Deirdre L. Replinger

Cal Poly Humboldt theses and projects

Increasing frequency, size, and severity of wildfires in western North America threatens forest-dependent wildlife species. The Pacific marten (Martes caurina) has historically been associated with mature, structurally complex forest throughout most of its range. Recently, martens have been detected in forests burned at high severity by the 2021 Dixie Fire—the largest recorded single fire in California state history. I used non-invasive remote camera traps and hair snares (n = 166 sites) to assess marten habitat use and density using spatial occupancy and spatial capture-recapture models. I detected martens across the burn severity gradient (unburned to high-severity) at …

Examining The Physiological Stress-Reducing Effects Of Virtual Nature Exposure And Slow Breathing, Jesse Benefiel

Cal Poly Humboldt theses and projects

In a time of excess stress, it is essential to examine accessible stress-reduction methods. Research has demonstrated that virtual nature exposure and slow breathing can independently reduce stress, but the literature is lacking with regard to their combined effects. The present study aimed to replicate independent effects of breathing and nature on stress and to test for potential effects, including whether their combination would produce an interaction effect. Using a 2 Environment (Natural v. Control) by 2 Breathing (Slow v. Normal) between-subjects design, 63 participants completed a modified color-word Stroop task to induce stress and were then exposed to either …

Species Boundaries Of The Rare Menzies’ Wallflower (Brassicaceae: Erysimum Menziesii), An Endemic Of The Northern California Coast, Cameron M. Jones

Cal Poly Humboldt theses and projects

Morphological similarity among geographically isolated populations can obscure deep evolutionary divergence, especially when convergent evolution under similar environmental conditions yields comparable phenotypes across independent lineages. Such cryptic diversity is likely underestimated in hotspots like the California Floristic Province (CFP), a global biodiversity hotspot, defined by its Mediterranean-like climate and encompassing most of California, southwestern Oregon, and northwest Baja California. The CFP is home to a disproportionate number of narrow endemics whose origins and evolutionary relationships remain poorly understood. Here, I investigate the evolutionary origins of Erysimum menziesii (Brassicaceae), a federally endangered California coastal dune endemic whose fragmented distribution has led …