1925 research outputs found
Sort by
Recreating and rethinking pot polish: an experimental analysis and zooarchaeological approach to the taphonomy of cooking fauna
No full textArchaeologically, the term pot polish refers to wear on skeletal elements resulting from cooking in a ceramic vessel. The active mixing, stirring, and rubbing of the materials within and against the vessel's abrasive interior leads to a polishing on butchered bone fragments. Unfortunately, limited experiments have been conducted on pot polish taphonomy and continues to be poorly understood. Those limited experiments, however, serve as the baseline for further exploring pot polish. Despite natural taphonomic processes producing similar polishing modifications, archaeologists use these cultural and natural attributes interchangeably. Given this lack of knowledge, investigations herein evaluate whether pot polish is in fact created by boiling bone in pottery used for cooking. Using zooarchaeology, ethnographic analogy, and experimental archaeology, this research tests and analyzes for sheen, smoothing, and beveling, all attributes ascribed to pot polish, on the bone surfaces after boiling in a coarse quartz sand ceramic vessel for three hours. This research is intended to demonstrate the extent to which pot polish, identifiable through a hand lens, is human produced. With all 453 specimens, 85 percent exhibit sheen, 72 percent exhibit smoothing, and 67 percent exhibit beveling on the broken tips or along the edges. Pot polish, therefore, is best defined as a cultural taphonomic effect when separated and viewed independently by each key attribute. Not only do the outcomes of these experiments contribute to current understandings of taphonomy this project uses a decolonizing position to challenge traditionally assumed archaeological narratives through zooarchaeological and experimental methods
Knockdown resistance mutations are widely distributed in fleas that transmit plague in Madagascar
No full textPlague remains an important human disease in certain countries of the world, especially Madagascar, where hundreds of human cases occur annually. The disease is caused by Yersinia pestis, a bacterium, and an important vector is the oriental rat flea Xenopsylla cheopis. In Madagascar, synthetic pyrethroids (SPs) have been frequently used for over two decades to control flea populations in human dwellings as a means of preventing plague transmission. With the heavy use of this single chemical class, resistance to SPs has emerged. The most common mechanism of resistance to pyrethroids arises from target site mutations in the voltage-gated sodium channel (VGSC), which have been described in many arthropod species. We investigated the occurrence of these mutations in X. cheopis by sequencing a region within domain II of the VGSC that is known to contain a resistance mutation (L1014F). We collected fleas from 23 locations in five provinces of Madagascar and performed phenotypic testing of individual fleas against 0.05% deltamethrin, 0.75% permethrin, and 4.0% DDT. Adult immersion tests of fleas followed the World Health Organization (WHO) protocol using strips impregnated with insecticide inside a test tube. We then extracted DNA from 1,303 individual X. cheopis. We found two single nucleotide polymorphisms (SNPs) that encode amino acid substitutions at amino acid position 1014, a known SP resistance position: the L1014F SNP was found in 24 of 25 field collections and occurred at a high frequency (83% of all fleas), whereas the L1014H mutation was very low frequency (4% of all fleas) but was spread across 11 field collections in the central highlands of Madagascar. We found a significant linear relationship between the frequency of kdr alleles and the proportion of individuals within each population that survived exposure to deltamethrin (r = 0.56, p = 0.016). To our knowledge, this is the first report of a correlation between a VGSC genotype and an SP resistance phenotype, as well as the first description of the L1014H mutation in fleas. The high frequency of resistance mutations in field-collected X. cheopis and our bioassay results suggest that resistance to SPs is common and widespread in Madagascar. The ability to detect these mutations in flea populations prior to insecticide treatment would be highly valuable for directing flea control efforts. Therefore, we developed a TaqMan PCR assay for public health officials in Madagascar that allows for the rapid detection of kdr mutations in order to maximize flea control efforts and, thus, reduce the transmission of plague to humans
Temporal estimation in child and adolescent clinical populations with diagnoses of depression, anxiety, or ADHD
No full textTemporal (time) perception has long been an area of interest for philosophers and researchers. It is foundational to how individuals conceptualize reality, and how they adjust behaviors and communication to suit specific physical and social environments. A number of factors influence one’s perception of time (i.e., age, affective state, medication, various mental health conditions, etc.). Research has yielded mixed results about individuals’ time perception ability and has largely focused on assessment of short durations (milliseconds to seconds). There has also been less focus on certain populations, such as children and adolescents with specific mental health diagnoses. The present study aimed to add to the research base by assessing the time estimation ability of children (ages 7-9, n = 68) and adolescents (ages 10-19, n = 116) on a one-minute prospective timing task (One Minute Estimation Test). Participants were grouped by mental health diagnosis of depression, anxiety, or ADHD. Age and gender differences were also examined. A factorial ANOVA was utilized to evaluate three research questions assessing whether children and adolescents with diagnoses of depression, anxiety, or ADHD tend to under- or overestimate the passage of one minute, and whether there were differences based on age and/or gender. The sample population (n = 184) was drawn from pre-existing data collected at a private neuropsychological clinic in the Southwest United States. A significant main effect was found for gender on time estimation. No other significant findings were found, but trends consistent with past research were evidenced. Anxious child and adolescent females were found to underestimate the passing of one minute, while anxious child and adolescent males tended to overestimate the passing of one minute. Male and female children and adolescents diagnosed with ADHD also underestimated the passing of one minute, while depressed adolescent males and females overestimated the passing of one minute. Limitations, implications for practice, and direction for future studies were also discussed
A fragile record of fleeting water on Mars: data
No full textThis dataset accompanies the manuscript "A fragile record of fleeting water on Mars" by Koeppel et al., published in 2021 in the journal Geology
Volcanic facies and geochemical analysis of the Triassic Mammoth Rock breccia as a test of early-arc paleogeography and subduction inception, eastern Sierra Nevada, California
Get PDFThe breccia of Mammoth Rock crops out in the Mount Morrison pendant in the eastern Sierra Nevada. The Triassic volcaniclastic facies of Mammoth Rock are a product of early arc magmatism that initiated after convergence began along a pre-existing transform fault. Early-arc paleogeography and subduction initiation that built the Sierra Nevada arc are poorly understood, despite decades of study. Early-arc paleogeography and induced subduction inception are recorded in the arc by tectonics including uplift, thrust faulting, and early-arc magmatism. The deposition, composition, magmatic source, and timing of magmatism for the breccia of Mammoth Rock provide an understanding of the arc paleogeography.The breccia facies dominantly contain angular to subrounded clasts with variable amounts of cuspate, jigsaw-fit, and fluidal clast shapes and flow-banded clast textures dispersed throughout. Interbedded sandstone facies are composed of alternating fine- to coarse-grained sandstone with bedding characteristics including planar laminated, lenticular, low-angle tabular cross-bedded, and massive. The volcaniclastic and siliciclastic facies of Mammoth Rock suggest deposition in a shallow-marine environment likely between shoreface and a shallow-continental shelf. Collapse of solidified lava flows resulting in submarine mass wasting is suggested by the clasts in the polymictic and monomictic facies. Whole-rock geochemical analysis of clasts in the breccia of Mammoth Rock reveals a trachyandesitic composition. Whole-rock geochemical analyses also show a high K2O and Al2O3 weight %, low Mg#, LILE and LREE enrichment, and HREE depletion that suggest dominantly an upper crustal magma source that fractionated from a primitive melt to an evolved andesitic melt and reveal geochemical signatures consistent with a thick continental crust. The breccia and sandstone zircon trace element geochemistry reveal medium to high U/Yb concentrations that aligns with whole-rock geochemical data, supporting the inference of a thick continental crust. Geochronologic analysis of zircon confine the timing of magmatism for the breccia of Mammoth Rock to ca. 225 - 216 Ma. Maximum depositional ages from detrital zircon in the sandstone facies suggest deposition as a result of mass wasting of breccia of Mammoth Rock occurred between ca. 222 Ma and 216 Ma
Developmental and behavioral impacts in zebrafish from heavy metal exposure
No full textArsenic (As) and Uranium (U) are naturally occurring elements found in the earth’s crust with levels varying between locations which can contaminate ground water and impact drinking water sources. The Navajo Nation for example contains unregulated wells that are used daily and may exceed current EPA maximum contaminant levels (MCL) of 10 μg/L As and 30 μg/L U. Translational models such as zebrafish and rats have demonstrated a decrease in kidney tubular function, induction of specific cancers, and an impairment in progeny development after As or U ingestion; however, these experiments generally employ doses that are many folds higher than what is commonly encountered. Furthermore, literature is extensive when investigating As and U effects individually, but research involving As and U in combination and their impact on general human development is limited. A modified fish embryo toxicity test (FET) was utilized to test the hypothesis that low-dose U and As mixture exposure induces negative developmental outcomes. Exposure to U and As mixtures resulted in an increase in movement, decrease in hatching, decreased absorption of the yolk sac, and decreased body malformations. To determine if the outcomes from mixture exposure could be explained by the effects of one of the two chemicals, separate As and U exposures and FET analysis were undertaken. Exposure to U and As individually and in combination resulted in an increase or decrease in movement, and a decrease in hatching, while exposure to U only resulted in an increase in movement and decrease in hatching. All other FET endpoints were unchanged by exposure. Delayed or decreased hatching was a consistent phenotype linked to U exposure, however, cathepsin L activity, an enzyme largely responsible for degrading the chorion to allow for hatching, was not affected following exposure to U. Although movement assessed by FET was reproducibly different in treated embryos compared to controls, the direction of the differences (more or less) was not consistent. While the FET surveyed movement at a single timepoint every 24 hours, a real time analysis leading up to hatching (usually between 48-72 hours post fertilization) showed a clear diminishment in overall movement in U-treated embryos. These results suggest even low-level exposure to uranium can impact motility. Although treatment regimens were limited in these studies, we demonstrated the feasibility of combining the FET, GMS, physiological assays and behavior as a sensitive approach for testing mixture exposure toxicity
Quantifying wild soil microbes: warming effects on taxon growth in the field
Get PDFMicrobes are dominant biota in soil where they interact with each other and plants, control nutrient cycling and greenhouse gas emissions, and determine carbon storage and release. Microbial communities and their activities are sensitive to temperature. The main goals of this dissertation are to obtain environmentally relevant measures of soil microbial growth in the field, quantify differences of the growing microbial communities in response to warming, and understand what drives this warming response. In Chapter 1, I introduce the theme of my dissertation which is that individual microbes are diverse in identity, function, and in their response to climate warming. I highlight the knowledge gaps in soil microbial ecology and why we must study individual microbes in a quantitative way. In Chapter 2, I introduce the main method used in this dissertation to quantify microbial growth, quantitative stable isotope probing (qSIP) with 18O-H2O. In Chapter 3, I determine if laboratory-based measurements of microbial growth inform field-based measurements of microbial growth and show that they do not. The remaining chapters utilize this field qSIP technique to quantify taxon-specific growth rate responses to warming in two ecosystems. Chapter 4 includes results from an elevation gradient transplant soil warming experiment from a mixed conifer forest, where plant-soil mesocosms were transplanted 15 years prior to a lower elevation site, the ponderosa pine forest. This experiment found that microbes decreased their growth rate with warming, likely due to a depletion in available carbon. The last two dissertation chapters focus on a short-term warming experiment to measure field growth rates of taxa in two sites along the Marr Ice Piedmont glacier chronosequence on Anvers Island, Antarctic Peninsula. In Chapter 5, I show that most microbial taxa increased their growth rate with warming. In Chapter 6, I show that phylogenetically related microbes did not grow or respond to warming at a similar rate, except for the early succession, bare fell-field soil that likely received an increase in available substrate from autotrophs responding to warming. I also determined that some functional groups including taxa involved in carbon and nitrogen cycling increased their growth rates significantly with warming. These studies provide valuable information for understanding microbial taxa activity, carbon and nutrient dynamics, and responses to environmental change, summarized in Chapter 7
The fecundity kernel: reproductive analyses to fill the gap in perennial graminoid demography
No full textThe goal of this project is to identify the functional traits and environmental conditions that drive variation in fitness (λ) and vital rates (survival, growth, and reproduction) for native perennial graminoids in the ponderosa pine (Pinus ponderosa Dougl. ex Laws.)-bunchgrass ecosystem of the American Southwest. Using our long-term data from 1-m2 vegetation maps, our plan is to quantify individual plant survival, growth, and reproduction for the most abundant perennial graminoids. However, reproduction data, a crucial element of any demographic and population model, remains elusive. My study quantified reproductive output for the ten most abundant perennial graminoid species in the ponderosa pine forests of the Southwest. I modeled the individual graminoid species reproduction using Integral Project Models (IPM) and the fecundity kernel, which requires information on reproductive output (number of seeds), probability of flowering, and recruitment as a function of the continuous state variable, plant size. In perennial graminoids, reproductive output is challenging to quantify because of the large quantity of seeds produced by each plant. I collected seed production data by graminoid species, and simultaneously collected data on the individual plant’s traits, specifically plant size, number of flower stalks, and maximum flower stalk height. These seed production and trait data were collected for each perennial graminoid species growing around the long-term permanent quadrats, which have been mapped annually for 19 years. I then developed equations to predict seed production as a function of these easier to measure plant traits. I also modeled the probability of an individual plant flowering as a function of plant size and the relationship between seeds produced and plant size for each species using regression techniques. To determine an average recruitment rate for each graminoid species, I quantified annual recruitment from the long-term 1-m2 vegetation maps and estimated reproductive output for each species based on plant size for the past 19 years. Finally, I used the reproductive output relationships, the recruit size distribution, and average recruitment rate to model the fecundity data for each of the ten perennial graminoid species. Although the probability of flowering and reproductive output were high for each species, recruitment rate was low indicating low levels of establishment. Population trends based on plant size are summarized in each fecundity kernel, and in general, perennial graminoid species produce offspring when individual plants are larger. Future studies will use IPMs to model vital rates (survival, growth, and reproduction) for these ten graminoids species and determine how tree shading, precipitation and temperature have affected these population trends
CRISPR-Cas9 mediated mutagenesis of the arsenic methyl-3- transferase gene in zebrafish
No full textArsenic pollution is a global problem. People exposed to arsenic suffer from health associated diseases such as skin lesions, liver damage, cardiovascular failure, and cancer. In the Southwest United States, geologically sourced inorganic arsenic can be detected in surface and groundwater, and in some cases contaminated drinking water supplies exceed safety limits set by regulatory agencies. Many studies have shown serious adverse health impacts from inorganic arsenic exposure in human and animals; however, studies have also identified a putative arsenic chemical defense mechanism, which is the essential activity of an arsenic methyltransferase enzyme, arsenic 3-methylene transferase (AS3MT). Previously known as CYT19, AS3MT orthologues have been identified in all kingdoms of life, and AS3MT is presumed to be a key enzyme for arsenic detoxification in vivo, by conversion of inorganic arsenic into the less toxic forms monomethylarsonous acid (MMAIII) and dimethylarsinous acid (DMAIII). Despite the worldwide problem of arsenic contamination and identification of AS3MT as a key arsenic defense enzyme, the mechanisms that drive AS3MT as a protective enzyme are not fully understood. Herein, bioinformatics tools and molecular experiments were used to predict critical amino acid motifs and to disrupt those motifs, respectively. The zebrafish AS3MT protein structure model was constructed by I-TASSER service and the amino acid network was analyzed by Residue Centrality Analysis (RCA). We utilize the CRISPR-Cas9 gene editing system to create two separate as3mt loss-of-function zebrafish lines, by targeting domains upstream (i.e., 5’ to the critical residues). We describe the design, gene editing, and genotype diagnostics that yielded the engineered zebrafish. Thus, our research activities represent the important steps toward testing the hypothesis that AS3MT is necessary for zebrafish survival and/or health in an arsenic rich environment
Perceptions of collective impact: a place-based systems approach
No full textThis study investigated students’ perceptions of a program referred to as CJP and its effect on their post-secondary enrollment and CJP partners’ perceptions of the utilization of the five conditions of collective impact. A case study methodology was used to investigate, describe, and analyze the perceptions of 10 students in one southwestern school district and five partners from the CJP collective impact initiative. The primary sources of data collected and analyzed were generated by in-depth semi-structured interviews with the students and a focus group of the partners. Additional data analyzed were memos, field notes, and artifacts which included the impact reports for a Free Application for Federal Student Aid (FAFSA) event and an enrollment event.
Major findings that emerged from this study related to students’ perceptions of CJP’s effect on their post-secondary enrollment. The majority of students defined the CJP FAFSA event as the most beneficial to their enrollment in post-secondary education. Students found that having dedicated time during school hours, on their high school campus, was beneficial in completing the application. Most of the students in this study reported the most meaningful event element was the role of teachers and their influence on applying for financial aid through the FAFSA event. Most often, students mentioned one specific teacher who seemed to go out of their way to ensure students understood the importance of completing a FAFSA.
Major findings that emerged from this study related to CJP partners’ perceptions of the utilization of the five conditions of collective impact. Through analysis of the data, it was clear partners of the CJP collective impact initiative did not understand the five conditions of collective impact. Partners could not define the conditions by name, and only loosely could explain what conditions were needed to create a collective impact initiative. Partners revealed having the right people at the table was relevant to a successful collective impact initiative. Many mentioned having partners, those considered “champions” involved as influential to the success of an initiative. At the same time, partners reported that the initiative had no consistency, either through partner turn-over, lack of commitment, and/or lack of follow-through