Soil solarization has been used throughout the world, but its effect on plant growth variables in ornamental tree saplings in the Willamette Valley are not well documented. Solarization could be an alternative to chemical controls for soil pathogens and weeds, and it may also influence plant growth factors. This study...
Sand dunes provide coastal communities critical protection from flooding and erosion, as well as a habitat for a range of species- some threatened or endangered. As such, it is of importance to develop a quantitative understanding of the processes through which these systems evolve at a variety of temporal and...
Floods remain the world’s most destructive natural hazard, despite centuries of efforts to minimize losses. Understanding public preferences for flood mitigation measures, and the impacts of these measures, is key to minimizing flood-induced losses. This study quantified tradeoffs between flood mitigation measures and determined factors that influence public preferences for...
Though currently relatively unknown outside Latin America, Andean root and tuber crops are rapidly gaining interest elsewhere. Tubers are a major food and important sources of nutrition in South America and have potential in countries outside their center of origin. We conducted a two-part study on oca (Oxalis tuberosa), mashua...
This thesis is an exploration of writing a music album from a singer-song writer perspective. It contains the process of writing lyrics and music, inspiration from other artists, as well as performance. It goes through the emotional ebbs and flows of creative writing, ground work for recording an album and...
Currently, wax printing is limited to materials that can be processed by a wax printer. Wax transfer printing is a method that allows previously unusable materials to be patterned with wax via an intermediate template. Millipore cellulose, a material too thick to be processed by a wax printer, was patterned...
According to the Center for Disease Control and Prevention (CDC), in 2015 10.4 million people worldwide became infected with tuberculosis (TB) with 1.8 million TB related deaths. Tuberculosis is a bacterial infectious disease caused by Mycobacterium tuberculosis, a slow growing yet highly infectious bacterium. Among the first line of treatments...
The goal of this project was to write a children’s book featuring same-sex and interracial families for children to both see themselves represented as well as to expose others to diverse, and increasingly common, family types. The creation of the book was guided by an analysis of the books available...
Yes-associated protein (YAP) in mammals and Yorkie (Yki) in Drosophila are functionally homologous proteins that partner with transcription factors to promote cell proliferation. The Drosophila protein Mask and its mammalian homolog MASK1 are examples of transcription factors that are essential for Yki/ YAP to drive transcription of target genes. Increased...
Canine Transitional Cell Carcinoma (TCC) makes up 2% of all canine cancers and is the most common cancer of the bladder for dogs. Usually diagnosed in its later stages, TCC is difficult to treat, with low survival times. Current diagnosis involves invasive techniques, and mainstream screening tests are often ineffective....
The goal of this project is to research an innovative rear wing design for Formula SAE and determine if the concept could be beneficial for automotive racing purposes. The research consists of three steps. First, sensitivity analyses using computational fluid dynamics (CFD) simulation were performed on multiple configurations. Next an...
Mycobacterium avium subspecies hominissuis (MAH) is the most common pathogen among non-tuberculous mycobacteria, causing disease in immunocompromised individuals. An intracellular bacterium, MAH resides within the phagosome, a vesicle formed by macrophages as they engulf invading pathogens. Here, a subpopulation of MAH regresses into a nonreplicative state called persistence, allowing them...
Prior to World War One, plastic surgery, as in its present form, was yet unfounded and not recognized as a genuine medical specialty. The carnage of the war prompted Britain to establish a specialized treatment center for plastic surgery, first at Aldershot and then at Sidcup, under the leadership of...
Water samples from the Arctic Ocean were analyzed in order to assess the present nature of particulate organic matter and investigate the effect of climate-driven changes on the ecology of the region. 661 individual surface water samples and 216 samples from CTD casts were collected from the Bering, Chukchi, and...
Increasing complexity and demand of healthcare has not been matched with policy changes and improvements in healthcare training. In Linn, Benton, and Lincoln Counties (LBL), a few challenges that prevent the efficient training of healthcare providers are (1) limited training capacity due to clinical placements and availability of qualified faculty...
The hypothalamic neuropeptide kisspeptin (Kiss-1) acts as a central component of the reproductive axis. A critical factor in pubertal progression and normal reproduction, this peptide is an afferent stimulator of gonadotropin-releasing hormone (GnRH), and is responsive to gonadal steroids, integrating steroid hormone signals and modulating GnRH secretion accordingly. Kiss-1 exhibits...
When people think of fossils, they generally imagine the bones of large, charismatic animals. However, small mammals are an ecologically important group of organisms that show up frequently in the fossil record, and can frequently function as indicators for local environmental and ecological conditions (Terry, 2007, 2010). Rodent and rabbit...
Diet History Questionnaires (DHQ) can only provide general information about a person’s nutritional intake. It is unable to cluster groups of people based on diets or lifestyles, nor identify specific foods that may play a role in disease prevention. The aim of this study was to validate the use of...
Nanophyetus salmincola is a well-studied parasite of their definitive mammal hosts. However, the conditions that signal the time for shedding of N. salmincola cercariae from their first host, the juga snail (Juga silicula), is not fully understood. A digenetic trematode indigenous to the American Pacific Northwest, N. salmincola can be...
Cystic ovarian disease (COD) is one of the main causes of infertility in dairy cattle and has a high economic impact on farmers. COD is caused by an endocrine imbalance within the hypothalamic-pituitary-ovarian axis which prevents the mature Graafian follicle from ovulating. The cause at the molecular level is not...
Over half of the U.S. coastline is found in Alaska, and the majority of the state’s economic activity occurs along the coast. Increased coastal development poses a potential threat to nearshore habitats in Alaska. The installation of artificial reef (AR) systems can mitigate habitat loss; however, few AR systems have...
4-H, an agriculture based youth program, promotes a variety of curricula in both agriculture and Science, Technology, Engineering and Math (S.T.E.M.) topics. However, science based curricula provided by this organization gravitates away from the programs agricultural roots. An effort was made to pilot a test on lesson plans that would...
In today, information plays a more and more important role in business world. The companies are full of data, but poor of valuable information extracted from that diverse data. Data mining, as a process of transferring data from variety perspectives to useful information, is the new trend for businesses. It...
The consumption of alcohol has been shown to have effects on health that are both harmful and
therapeutic, depending on the amount that is consumed. Alcohol’s effects can be damaging to the body in excess but, in moderation, can act as a protectant against certain conditions. The two studies discussed...
Gene expression in plants (and other eukaryotes) is a very complex process. Gene expression is primarily controlled by proteins and their binding sites near the gene in the chromosomal DNA. More specifically, interactions among transcription factors (DNA-binding proteins) and cis-regulatory modules (CRMs-sets of binding sites) control the expression of nearby...
The aging process is a biological phenomenon in mammals that heavily contributes to the onset of chronic diseases. While there are many theories that attempt to explain the biological onset of aging, one emerging theory involves chronic inflammation. Chronic inflammation has been previously linked to several age-related diseases and is...
Augmentative and Alternative Communication (AAC) devices enable people who cannot speak to communicate with others. Unfortunately, they are tedious to use and are believed to lower the satisfaction of interacting with others. This thesis attempted to document the impact that AAC devices have on social interactions, in the hope of...
Haemonchus sp. is known to be present in geographical regions of Oregon that are more arid and warm, which has been the preferred climate of this parasite. However, it was not detected in Western Oregon bovine until recently. Haemonchus sp. was first detected in Western Oregon bovine from a fecal...
The Law entitled ‘Title IX’ was designed to address the prevalent practice of institutionalized discrimination against women. The law aimed to introduce and reinforce the equal treatment of minorities and women at workplace and educational institutions. Title IX made some significant improvements in the system through the promotion of social...
Nanophyetus salmincola is a well-studied parasite of their definitive mammal hosts. However, the conditions that signal the time for shedding of N. salmincola cercariae from their first host, the juga snail (Juga silicula), is not fully understood. A digenetic trematode indigenous to the American Pacific Northwest, N. salmincola can be...
Miniature satellites called cubesats have been gaining increasing popularity in
both academic and private spaceflight ventures. NASA's Jet Propulsion Laboratory
has recently been accepting design proposals for a cubesat mission to Europa, where
solar and battery power would be inadequate power sources. In this thesis, a
radioisotope powered cubesat was...
Research in Dolan lab focuses primarily on the adaptive immune system and ways it can be better utilized to eliminate infected or transformed cells. Research focuses on the major histocompatibility (MHC) class I antigen presentation pathway, which plays an important role in alerting the immune system of the presence of...
As conventional energy sources begin to deplete, the need for alternative, renewable
energy becomes more necessary. Dimethyl ether (DME) fuel cells are a promising
energy source that could fulfill these demands. Compared to well-known fuel cell
fuels, such as methanol, DME has a low toxicity and high energy density.
Experimental...
This project studied how a user's handedness affects his or her ability to use a
special-purpose handheld digital device such as a digital camera or rangefinder. More
specifically, it sought to identify how handedness affects speed and accuracy when
navigating within a menu system. 24 participants were given 8 menu...
Developmental research has suggested that parenting practices may impact the
development of risk behaviors later in life. However, little evidence exists regarding
how parenting may impact actual decision processes that precede poor choices. This
study examined how parenting practices in early childhood influence the development
of decision-making competence (DMC), a...
Treatment of extrahepatic portosystemic shunts provides many options, including cellophane banding. These cellophane bands are secured with a ligation clip. Weck® offers two forms of these: the stainless steel Hemoclip, and the polymer Hem-o-lok. This in vitro study compares the mechanical strength of these two of types of clips by...
The Marinoan Snowball Earth ended 635 Ma ago during the Neoproterozoic Era, after an interval in which the Earth was completely covered by glaciers. Thawing of these glaciers formed cap carbonates across shallow marine depositional environments. The Noonday Formation is a cap carbonate that formed after the deglaciation of the...
Cytochrome P450 1B1 (Cyp1B1) is a xenobiotic metabolizing enzyme, responsible for polycyclic aromatic hydrocarbon (PAH) oxidative metabolism. CYP1B1 metabolically activates several species of environmentally relevant procarcinogenic PAHs to reactive carcinogens. PAHs are aryl hydrocarbon receptor (AhR) agonists, leading to CYP1B1 upregulation. Though CYP1B1 is highly conserved across species, wild type...
Human body flight is a relatively young sport with a largely undocumented history.
Human body flight is an umbrella term for any sport involving maneuvering one’s body in a
meaningful way through a column of relative wind. Human body flight includes skydiving,
which was the origin of human body flight,...
Embryonic development, where organs and major structures begin to develop, requires precise coordination of numerous gene regulatory pathways. Fendrr is an long non-coding RNA (lncRNA) that plays a role in regulating gene expression in mesodermal tissues during early embryonic development in mouse. The lateral plate mesoderm (LPM) is an earlier...
The Ratio Mountain Quadrangle is located in Southwest Montana, East of the city of
Butte. This quadrangle features two major geologic units; the Elkhorn Mountain
Volcanics, a series of several ignimbrites of varying composition, and the Boulder
Batholith, a large granite pluton that rose through the EMV. Previous studies in...
Carcinus maenas is an invasive marine predator. Its generalist feeding strategies make it one of the most effective invaders. Carcinus maenas has invasive populations throughout the world, and was recently introduced to the west coast of North America. This study looks at the abundance and growth of C. maenas in...
Utilization and preference of whelk shells by the hairy hermit crab are examined in the following to further define the ecology of Oregon’s mid to low intertidal ecosystems. The study was conducted at Tokatee Kloochman State Natural Area (TK) where I made observations before collecting data. My observations were of...
Utilizing Danio rerio (zebrafish) as a model organism has gained popularity recently, however a lack of research into their immune response pathways had led to the discovery of subclinical infections, and has potentially confounded results. We conducted a study to determine the cytokine expression from TLR activation in order to...
We construct a Monte Carlo simulation in Python to calculate optical flashes at 5x10¹⁴ Hz peaking at 6x10³¹ erg s⁻¹Hz⁻¹St⁻¹ due to synchrotron radiation from the reverse shock of a gamma-ray burst’s jet. While analytical solutions to this problem exist, they rely on sweeping simplifications of what is necessarily a...
Invasive breast cancer affects 1 in 8 women during their lifetime. Current cancer research uses 2-D cell culturing, which does not accurately represent tumor behavior. In comparison to tumors, cells grown using 2-D cell culturing have different proliferation and diffusion rates, cell shapes, and gene expression. To improve in vitro...
T. pseudonana biosilica and live cells was explored as a biosensor for detection of the explosive compound 2,4,6-trinitrotoluene (TNT) in aqueous solution. The diatom frustule is an intricately nanostructured, highly porous biogenic silica material derived from the shells of microscopic algae called diatoms. This material emits strong visible blue photoluminescence...
Previous research has shown significant improvements in standard measurements of student learning in traditional classroom settings when constructivist instruction techniques are skillfully applied as opposed to its traditional counterpart, direct instruction. The purpose of this study is to apply the concept of constructivism in musical instruction. The working hypothesis is...
The Bcl-2 family of proteins regulate cell survival and are targets for cancer therapy. This protein family has also been implicated in chemotherapeutic resistance, the cause of approximately 90% of treatment failure in advanced cancer. We analyzed the expression and the role of the Bcl-2 proteins in chemotherapy resistant breast...
Quantum yield is an important, characteristic quantity to be measured for fluorescent compounds. Here, a comparative method between fluorescent compounds in solution is applied to measure unknown quantum yields. An absorption spectrometer was used to measure the absorbances of two different fluorescent quantum yield standards. The integrated fluorescence intensities were...
Genetic engineering techniques allow scientists to create plants with desired traits. However, there is unwanted variability in transgene expression due to enhancer-promoter interactions and the influence from genetic elements near the insertion site of the transgene, which integrates into a random location in the genome. In an attempt to reduce...
Incompatibility between Fenton’s Reagents and a potassium dichromate COD test provides interference that prevent accurate measurements of the concentration of organics from oxidized samples. Several treatment options were tested to remove this interference. Oxidation of reagents was eliminated as a potential method for removal of interference due to sample contamination....
Gold nanostars are a relative newcomer to the nanoparticle scene, and their unique properties make them very desirable for spectroscopic applications. These nanoparticles, with their sharp tips, create electric field enhancements that interact with light in an advantageous way. This Thesis outlines our in-depth study of gold nanostar synthesis, the...
The structural and chemical diversity of natural compounds represents a vast amount of potential in terms of new drug discovery. This project examines the cytotoxic potential of the marine natural product mandelalide A and seeks to understand whether or not exposure to this compound induces programmed cell death in cancer...
The purpose of this project was to design the 2016 combustion car drivetrain for Global Formula Racing (GFR). The goal of this project was to improve upon the 2015 drivetrain design by reducing complexity, weight, and maintenance time. To reduce complexity the spool was changed to a one piece system...
Koi herpesvirus (KHV) is a new emerging viral pathogen of koi and common carps. It has been demonstrated that KHV becomes latent in the white blood cells in the recovered koi. The latent KHV can be reactivated under stressful conditions, such as heat and injury, and the reactivated viruses can...
Stormwater picks up pollutants as it flows over impervious surfaces before ending up in water resources. Best management practices are implemented to remove pollutants from stormwater. Puralytics manufactures a stormwater treatment product called the LilyPad. The LilyPad consists of a titanium dioxide nanoparticle photocatalyst immobilized on polypropylene substrate. Treatment of...
Monitoring mercury (Hg) exposure in avian populations is critical to understanding the effects of this neurotoxin. Avian Hg exposure is commonly evaluated by measuring Hg concentrations in internal tissues, blood, and feathers. Feathers are a popular sampling matrix due to ease of sampling and limited stress to birds. However, it...
Background: Certain knee movements place the anterior cruciate ligament (ACL) at risk of injury. These injuries commonly affect athletes especially at the end of events. The purpose of this study was to determine the effects of exhaustive exercise on frontal plane hip and knee mechanics during two tasks in order...
We present an analysis of the relationship between spectral lag and luminosity in time-resolved segments of long gamma-ray bursts detected by BATSE, an experiment aboard the Compton Gamma Ray Observatory satellite. For full bursts, there is a well-established correlation between the lag, which is easily computed, and the total burst...
This project consists of the analysis, design, and manufacturing of the 2016 cooling system for Global Formula Racing’s combustion vehicle. Several water configurations were examined, using computational fluid dynamics (CFD) to estimate airflow and heat transfer calculations in MATLAB to estimate heat rejection through each concept. Data used to perform...
Crystal morphology and dimensionality of single-crystal semiconducting materials can have dramatic effects on the optical and electrical properties. Organic photovoltaic (OPV) materials and fluorinated graphene folds are two materials that show these dependencies. Anthradithiophene (ADT), is an OPV that can be functionalized with different side groups to form different crystal...
Current methods in traction force analysis rely on a homogeneous extra-cellular matrix and
embedded microbeads to track deformations. The efficacy of these methods decreases when the matrix is not homogeneous. In heterogeneous matrices, beads often aggregate in regions of higher matrix density and float in regions where matrix substrate is...
Recent interest in nano aerial vehicles (NAVs) has sparked an increase in research on the mechanics of biological flapping flight. The ability of NAVs to fly in confined spaces and perform tight maneuvers make them a valuable technological asset. Researching the mechanisms behind small-scale flapping flight promises progress toward the...
High field time-domain terahertz spectroscopy (TDS) is used to determine the time dependent transmission and the time-delay and optical-power dependent conductivity of a wafer of gallium arsenide (GaAs). Gallium arsenide is a direct band-gap semiconductor and has potential as a computer processor component. Analysis of the transmission of terahertz (THz)...
This particular study focuses on the changes in the ideas and perspectives of Nicaraguan women throughout the span of several generations. With the gaining popularity and successful strides that women have made to advance the Women’s Movement in Nicaragua, the definition of empowerment, the ideology of stereotypes, and the manner...
The purpose of this thesis was to understand the relation between the actual performance and the design performance of the manufacturing plane which was designed for the 2016 Design/Build/Fly competition. The actual performance was determined using an Arduino Uno based system with data from an accelerometer, gyroscope and pitot tube....
Background: The capability of an individual to produce force rapidly is important for performance of sporting activities and to stabilize a joint to protect against injury. Rate of torque development (RTD) and contractile impulse (CI) may be more effective than peak torque in assessing rapid torque production. The relationship between...
As global population and affluence continues to rise, demand for and disposal of
consumer products is increasing. Currently, there are established process that guide
designers to develop innovative products, but these products still have a large impact
on the environment. There is beginning to be an emphasis on product sustainability,...
Insoluble surfactants are unique molecules that have the ability to manipulate interfacial properties, becoming useful in numerous applications such as detergents, wetting agents, emulsifiers, foaming agents, dispersants, and more. Interfacial rheology is a field that attempts to characterize the flow properties of insoluble surfactants by exerting a stress on the...
Autism Spectrum Disorder (ASD) is described as a developmental disability characterized by impairments in social interaction, communication, and repetitive or restricted movements. It has been shown that as children with ASD age, their cognitive and social skills improve with time, and physical activity has been linked with improving aspects of...
Autobiography is usually categorized with essays and other technical writings, and rarely considered creative or artistic literature in the public eye. This project explores the elements of autobiography and two authors who break the barriers of conventional practices to create works that also function as creative and artistic literature. Maya...
Surface patterning of bacterial biofilm provides an opportunity to understand the microbial metabolic exchange between bacterial species. By using various techniques, one can put different bacterial species in close proximity and study their interaction by using various assay kits and analytical techniques. In this study, surface patterning of Pseudomonas aeruginosa...
Microalgae play an important role in the marine ecosystem. They are primary producers and form the base of the aquatic food web. The effects and changes that occur to microalgae are expected to have influences on the higher tropic levels. One major factor that influences growth of microalgae is the...
The purpose of this study was to investigate the effects of wildfire on soil hydraulic properties of forested hillslopes. The study site was located within the Stouts Creek wildfire, which burned approximately 10,705 ha of forest in southwestern Oregon in summer 2015. Three soil hydraulic properties (soil moisture, unsaturated hydraulic...
This project created a stand-alone unit capable of providing on-board sensing and processing for robotic vehicles. This unit was designed to be compact, lightweight, inexpensive, and adaptable. The goal of this project is to help advance robotics research in mapping and multi-agent coordination by making it easier to equip vehicles...
Recent studies have discovered that salmon, specifically juvenile Coho Salmon, have their olfactory senses inhibited by the presence of low concentrations of copper concentrations at very low concentrations. Much of this copper is deposited on roadways by car brake pads during their use. The copper is carried with stormwater into...
Little work has been conducted regarding the net returns of forest lands. The Ricardian model is ripe with potential to estimate the effects of climate on net returns to forestry.
Multiple linear regression allows each climate variable to measure its effect of net returns with the assumption of all other...
Although Latino students make up more than a quarter of the U.S. public school system, only three percent of children’s literature either features a Latino protagonist or is written by a Latino author (Machado et al.). Latinos are therefore severely underrepresented in children’s books. Additionally, studies have revealed that Latino...
Ultraviolet (UV)-protective compounds, such as mycosporine-like amino acids (MAA) are critical for the survival of marine organisms exposed to high-solar radiation. A chemically similar compound, gadusol, was discovered in eggs of the atlantic cod in 1980, and was originally thought to be derived from MAAs that had been ingested. However,...
Vibrio cholerae (Vc), the etiological agent of cholera, has developed many mechanisms to combat the great fluctuations in pH, ion content and osmotic conditions of the vastly differing environments it encounters through its infections of the human host. A series of cation antiporters are found in the Vc membrane to...
Robotic global navigation is often based on the assumption that the world is static. It assumes that obstacles present in maps will be there later and new obstacles will be dealt with by a local planning algorithm. When robots interact in an environment inhabited by people, this assumption does not...
Background: The use of a lower extremity injury prevention program (IPP) by female athletes before the completion of puberty may mitigate movement changes that develop during puberty and contribute to greater injury risk. It is unknown whether player age influences coaches’ knowledge, attitudes, and behaviors surrounding IPPs. Methods: Fifty-four female...
Participation in school garden programs improves health outcomes in K-12
student and is an effective tool for experiential learning. Although most schools in the Corvallis School District have a school garden, none are currently integrated into the curriculum. Using a cross-sectional,online survey, I learned that the majority of parents of...
The Pacific coast sea anemone Anthopleura elegantissima is an excellent model organism for the study of temperate symbiosis due to its unique relationship with two microalgal symbionts, Elliptochloris marina and Symbiodinium spp. In addition to hosting one or both of these symbionts, A. elegantissima can live aposymbiotically, allowing for the...
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is an important regulator of immune responses in various disease models. In the non-obese diabetic (NOD) mouse model of type 1 diabetes, activation of this receptor leads to suppression of the autoimmune response and limits immune cell infiltration of...
Approximately 37.6% of Fiji’s population is comprised of individuals that have
Indian descent (2007 census). This is primarily due to the recruitment of Indian
indentured servants to work on the sugar plantations of Fiji during British colonial
rule in the 1880s. Many descendants of these servants have since moved to...
Adolescent pregnancy and childbirth are the second leading cause of death for teen girls worldwide. In Multnomah County, as throughout the United States, teen pregnancy rates are high and disproportionately affect the Hispanic community. Hispanic adolescent females have a teen pregnancy rate over two times higher than white adolescent females....
Early Childhood Caries (ECC) is the most common chronic childhood disease, affecting more than 40% of children by the time they reach kindergarten. A bacterium known as Streptococcus mutans is the primary source of infection, but multiple other factors play a significant role in the progression of the disease. Studies...
Markov chains, discovered over one hundred years ago by Andrey Markov in an
attempt to analyze the distribution of vowels and consonants in Russian poetry, have
evolved in multiple fields over the last century to become a mainstay of statistical
modeling and computation. maRkov is a package of software to...
When iron levels are low, the opportunistic pathogen Pseudomonas aeruginosa secretes the high-affinity iron-binding siderophore pyoverdine. The cognate ferripyoverdine receptor, FpvA, has gained attention as the most divergent gene in the organism’s genome, showing substantial evidence of positive selection. S-type pyocins, bacteriocins with specificity to Pseudomonads, enter cells through FpvA...
Ceratonova shasta is a myxozoan parasite that affects populations of salmonid species in the Pacific Northwest and is the cause of enteronecrosis. It has a complex life cycle involving two hosts; a definitive annelid host, Manayunkia speciosa (polychaete), and an intermediate salmonid host. Klamath River M. speciosa are genetically variable...
In the United States, the state of housing and the lack thereof has been
declared a national crisis. In response, cities have taken measures to police behaviors
that are associated with what they perceive to be disorder and decay. These behaviors
are also commonly associated with houselessness. Laws that criminalize...
Midwives in the Unites States frequently prescribe herbs and other complementary and alternative therapies for the common complaints of pregnancy, labor, and the postpartum period. Although many studies have reported quantitative data on midwives utilization of herbs, this research aims to convey ethnographic information on midwives use, beliefs, and perceptions...