Life Sciences Commons^™

Investigating Seed Maturation And Mortality: A Mechanism For Post-Fire Regeneration In Non-Serotinous Conifers, Madeleine A. Lopez

Cal Poly Humboldt theses and projects

Climate warming and associated dry conditions are contributing to increased fire frequency, severity, and size, for many regions in western North America. These changes in fire activity have prompted concern over the long-term persistence of some conifer species, specifically those not adapted to withstand high-severity fire. However, regeneration of non-serotinous conifer species is possible if the timing of fire occurs following seed maturation, and within a heat range that seeds can withstand, in a regenerative mechanism termed “facultative serotiny.” To address this mechanism, I determined the timing of conifer seed maturation using viability testing for four California conifer species: ponderosa …

Drought, Tree Mortality, And Regeneration In Northen California, Sophia Lb Lemmo

Cal Poly Humboldt theses and projects

The 2012-2016 California drought was the most severe in the state’s recorded history, contributing to the death of millions of trees. While the effects of this drought on forests are relatively well studied in the central and southern Sierra Nevada, less is known about its effects on the heavily timbered and diverse forests of northern California. Through sampling 54 0.25 ha plots in northern California, this study compared tree mortality and regeneration patterns before, during, and after California’s most recent record-setting drought. This study evaluated 1) the influence of habitat and competitive covariates on mortality and regeneration trends using ridge …

Foraging Behavior Of Honeybees Exposed To Mosquito Insecticides, Samantha Marie Diel

Cal Poly Humboldt theses and projects

The main aim of this study was to quantify the effects of mosquito insecticides on honey bee (Apis mellifera), foraging behavior, explicitly assessing the impacts of adult mosquito control practices on honey bee health. The extent to which honey bees are exposed to pyrethrum, pyrethrins, permethrin, and pyrethroids is unknown, as are their effects on honey bee health and vitality. This study sought to answer this question by exposing honey bees to D-Phenothrin with the addition of Piperonyl butoxide (PBO), one of many synthetic pyrethroids widely used against adult mosquitoes to control mosquito-borne diseases. Honey bees were exposed to …

Does Bisphenol-A, An Estrogen-Like Environmental Toxin, Disrupt Expression Of The Neuronal Chloride Exporter Protein During Early Brain Development?, Mayra S. Mendez

Cal Poly Humboldt theses and projects

Bisphenol A (BPA), a manufactured compound found in consumer products, is known to adversely affect early brain development by disrupting normal estrogen signaling. Recently, BPA was reported to suppress expression of a gene encoding the neuron-specific chloride ion transporter, KCC2. Human and animal studies show suppressing KCC2 can cause neuronal and behavioral hyperactivity. Therefore, some adverse effects of BPA may be due to KCC2 suppression and consequent neuronal hyperactivity. This study aimed to determine whether BPA exposure during brain development alters KCC2 expression. A secondary purpose was to evaluate whether a new transgenic zebrafish line, KCC2:mCitrine,could be used to track …

Winter Sandpiper Communities On Humboldt Bay: High-Tide Roost Use And Habitat Features That Influence Roost Site Selection, Chelsea Polevy

Cal Poly Humboldt theses and projects

Roosts, locations at which birds and other animals come together to rest and preen while remaining vigilant for predators, are a common facet of the nonbreeding biology of many shorebirds. Roosts fall on a continuum from traditional to ephemeral; traditional roosts are used consistently by the same individuals, whereas ephemeral roosts are used inconsistently and may be used only once or a few times. Studies show that roost habitat preference is the result of an individual shorebird’s attempt to optimize the costs and benefits associated with time constraints, energetic demands, and danger risks as they relate to overall fitness.

In …

Characterizing The Relationship Of Lgl1 And Akt In Migration Of Murine Neural Stem And Progenitor Cells, Natalie Pedicino

Cal Poly Humboldt theses and projects

Asymmetric cell division and migration are critical for neural stem cell differentiation and brain development. When these processes are dysregulated in neural progenitor cells (NPCs), developmental defects and diseases like glioma can result. Lgl1 is a tumor suppressor gene that was first characterized in Drosophila neuroblasts (Strand et al., 1994). It is best known for its regulation of asymmetric cell division through its association with the Par complex. The PI3K/AKT signaling cascade is involved in cellular migration and is also regulated by Par signaling. Unpublished data from the Sprowles laboratory suggests a potential role of Lgl1 in migration and other …

Investigating The Genetic Diversity Of Immune Genes In Non-Native Populations Of American Bullfrogs (Rana Catesbeiana), Luisa Nereyda Segovia

Cal Poly Humboldt theses and projects

The American Bullfrog (Rana catesbeiana) is a highly invasive species that has successfully colonized habitats around the world. The genetic variability of immune genes within invasive populations, like that of bullfrogs, may contribute to how resistant a population is to pathogens. The objective of this project was to characterize the genetic diversity of an immune gene in invasive bullfrog populations in California to better understand how persistent these populations might be over time. To characterize immune gene variability, I isolated exon 2 of the Major Histocompatibility Complex (MHC) Class II Beta chain gene and a neutral mitochondrial marker, …

Degradation And Nitrogen Cycling In The Context Of Biodiversity-Ecosystem Function Relationships In The Inquiline Bacterial Community Of Darlingtonia Californica, Megan Teigen

Cal Poly Humboldt theses and projects

Biodiversity-ecosystem function (BEF) research aims to explain how species and their environments interact with each other. Microbial communities engage in vital biogeochemical pathways in a variety of natural ecosystems, and yet there are large knowledge gaps about the specific metabolic pathways in which they are involved. Degradation specifically contributes to nitrogen cycling globally through the breakdown of large organic nitrogen compounds into small inorganic nitrogen that is necessary for the survival of many other organisms. In this study, I focused on the degradative function of the inquiline microbial communities found within the carnivorous pitcher plant, Darlingtonia californica. Darlingtonia grows in …

A Preliminary Study For The Development Of Free Weight Back Squat Muscular Fitness Reference Norms For Adults Aged 19-29, Eden G. Marquez

Cal Poly Humboldt theses and projects

The barbell back squat is a simple and common resistance training exercise that is used to evaluate muscular fitness. Its use as an evaluative method for muscular fitness in the general population is limited due to a lack of published reference values for this free weight exercise in the general population. This study presents reference values for the back squat muscular fitness in healthy active young adults (aged 19-29). This data is made of 399 subjects (51% male/49% female). Mean ±SD for participants in anthropometric data were 23.1±2.8 years of age, 73.0±12.9 kg weight, 170.6±9.4 cm height, and 25.0±3.4 body …

Escherichia Coli And Salmonella Sp. In Domestic Cattle And Wild Roosevelt Elk: Fecal Pathogens At The Wildlife-Domestic Interface, Emily A. Buck

Cal Poly Humboldt theses and projects

Direct or indirect contact between domestic populations of animals and wildlife carries an inherent risk for transmission of pathogens that cause infectious disease. In Humboldt and Del Norte counties of northern California, ongoing conflict between ranchers and Roosevelt elk groups results from elk use of ranching pastures and pastures on private land. Fecal samples from elk in association with cattle, cattle, and from elk not in known association with cattle were assessed for the presence of bacteria Salmonella enterica and pathogenic Escherichia coli to assess whether association with cattle increases risk of infection for elk. Group identity (one of the …

Demographic Modeling Of Conservation Strategies For The Yosemite Toad (Anaxyrus Canorus), Corrina Rebecca Kamoroff

Cal Poly Humboldt theses and projects

The Yosemite toad (Anaxyrus canorus) is an anuran species endemic to the Sierra Nevada in California that, like many amphibians globally, has suffered population declines. The documented decline in A. canorus populations across their historic range highlights the need for an effective management strategy to protect the species from future extirpation. For this study, I estimated survival rates of A. canorus using a Cormack-Jolly-Seber model populated with data from a demographic study. I then used a female-only post-birth pulse stochastic Lefkovitch matrix model using vital rates I estimated and from the literature to simulate the effect of different …

Prevalence Of Rickettsia Sp. Phylotype G022 And Rickettsia Tillamookensis In Ixodes Pacificus Nymphs From Northern California, Erin Rose Trent

Cal Poly Humboldt theses and projects

Back in 2011 an unknown Rickettsia species was discovered in adult Ixodes pacificus and became known as Rickettsiaspecies phylotype G022. Preliminary analyses placed it among the Spotted Fever Group Rickettsia, indicating unknown pathogenicity. Another Rickettsia species previously found in I. pacificus, R. tillamookensis, was only recently the subject of research efforts after its original discovery in the 1960s. The main focus of this research was to determine the prevalence of phylotype G022 in nymphal I. pacificus to gain further insight into this tick-Rickettsia relationship. The prevalence of R. tillamookensis was also a topic of this …

The Promise And Perils Of Molecular Combing, Jeanmarie Mishler

Master's Theses and Doctoral Dissertations

Dynamic Molecular Combing (DMC) is a method of making visible single molecules of DNA. The method stretches the molecules, attaching them to a glass coverslip; labels them with an intercalating dye or fluorescent antibodies; and images the molecules with fluorescent microscopy. After combing, fluorescent in situ hybridization (FISH) can be used to inspect regions on the DNA molecule. DMC is especially technically challenging for undergraduate research laboratories. To make the technique accessible to an undergraduate laboratory this project addresses three challenges: pH of buffer solution, NaOH exposure time, and halogenated thymidine exposure time in yeast (Saccharomyces cerevisiae). A serial pH …

A Pantropical Assessment Of Deforestation Caused By Industrial Mining, Stefan Giljum, Victor Maus, Nikolas Kuschnig, Sebastian Luckeneder, Michael Tost, Laura J. Sonter, Anthony J. Bebbington

Geography

Growing demand for minerals continues to drive deforestation worldwide. Tropical forests are particularly vulnerable to the environmental impacts of mining and mineral processing. Many local- to regional-scale studies document extensive, long-lasting impacts of mining on biodiversity and ecosystem services. However, the full scope of deforestation induced by industrial mining across the tropics is yet unknown. Here, we present a biome-wide assessment to show where industrial mine expansion has caused the most deforestation from 2000 to 2019. We find that 3,264 km2 of forest was directly lost due to industrial mining, with 80% occurring in only four countries: Indonesia, Brazil, Ghana, …

Analyzing Factors Influencing Secondary Agricultural Education Teachers’ Skill Level In Welding, Rafael Bakhtavoryan, Douglas D. Lavergne

Faculty Publications

The effects of secondary agricultural education teachers’ demographic characteristics on their propensity to become more skilled in welding were examined by estimating an ordered logit model for teachers in Northeast Texas. The sample of teachers was derived from the Agricultural Mechanic Competency Development survey for 2015. According to the estimation results, relative to female, being male was positively associated with being more skilled in welding. Compared to having a Master’s degree, having only a Bachelor’s degree was negatively associated with being more skilled in welding. Having five or less years of teaching positively affected becoming more skilled in welding compared …

Meet The Staff

The Synapse: Intercollegiate science magazine

No abstract provided.

Left On Red: The Chemistry Of Color, Rebecca Fenselau, Kayla Bertholf

The Synapse: Intercollegiate science magazine

No abstract provided.

How Machine Learning Will Change Our World: How Machine Learning Can Make Life Easier - And A Bit More Complicated, Sakin Kirti

The Synapse: Intercollegiate science magazine

No abstract provided.

Monkey See, Humans Too: Understanding The Link Between Sight And Smell In Five Primate Species, Paul Kamitsuka, Evan Swanson

The Synapse: Intercollegiate science magazine

No abstract provided.

Eczema And Mental Health: The Silent Struggle Of Skin Disorders, Bhavana Huliyar

The Synapse: Intercollegiate science magazine

No abstract provided.

The Acoustics Of Concert Halls: Where Science, Music, & Visual Arts Meet, Norah Han

The Synapse: Intercollegiate science magazine

No abstract provided.

Emulsifiers: The Hidden Ingredients Holding Our Food Together, Joey O'Donnell

The Synapse: Intercollegiate science magazine

No abstract provided.

Earth's Other Lung: Phytoplankton, Sarah Barney

The Synapse: Intercollegiate science magazine

No abstract provided.

What Your Ears "Say" About You: Otoacoustic Emissions, Fay Levin

The Synapse: Intercollegiate science magazine

No abstract provided.

Microplastics In Coral Reef Skeletons: A Threat To Coastal Ecosystems And A Reservoir For Pollutants, Isabelle Small

The Synapse: Intercollegiate science magazine

No abstract provided.

The Food Dye Is Cast: What They Are, Why We Need Them, And If They Are Killing Us, Joey O'Donnel

The Synapse: Intercollegiate science magazine

No abstract provided.

Cerebral Palsy: Understanding The Disease, My Trinh

The Synapse: Intercollegiate science magazine

No abstract provided.

The Tale Of George Wright, Caroline Ward

The Synapse: Intercollegiate science magazine

No abstract provided.

Untitled (Illustration), Isabel Giammusso

The Synapse: Intercollegiate science magazine

No abstract provided.

Untitled (Illustration), Shruti Narayan

The Synapse: Intercollegiate science magazine

No abstract provided.