Concentration of Heavy Metals in Tijuana River Estuary Sediment

Wetland habitats have a unique combination of characteristics including high nutrients and shallow, brackish water, that allows them to support a number of sensitive organisms. Many estuarine ecosystems are now suffering due to anthropogenic activities and major economic growth. Heavy metals have a number of impacts on estuarine ecosystems including toxicity when found in high enough concentrations. Due to their impact on local species, heavy metal concentrations can provide valuable insight as to the health of the ecosystem. This study aims to determine the abundance and spatial distribution of heavy metals in the Tijuana River Estuary system. We collected sediment samples in the Tijuana River Estuary in July 2017 using a transect method in the south, east, and western areas of the estuary. Additional transects were collected when possible. We collected and analyzed a total of 69 sediment samples using an X-Ray fluorescence (XRF) machine to determine the abundance of six metals known to influence the health of estuarine environments: nickel, arsenic, lead, mercury, copper, and zinc. The metal concentrations were then spatially analyzed in ArcGIS 10.4. Heavy metal particles tend to attach to fine sediment particles, so it was hypothesized that concentrations would be highest in the floodplain where the finest sediment particles settle. The results of the study supported our hypothesis that concentrations would be highest in the floodplain, and several metals were found at levels that exceed EPA regulatory standards

Queer pedagogy : performing outside the lines

textThis qualitative study reflects on my experiences as a queer pedagogue developing a Lesbian, Gay, Bisexual, Transgendered/Transsexual, Questioning/Queer, and Ally (LGBTQA) youth theatre ensemble, Outside the Lines. Through the analysis of my pedagogy and the pedagogy of three practitioners affiliated with the Pride Youth Theatre Alliance, I explore how my queer culture, language, expression and politics influence my Applied Drama & Theatre practice within educational and community spaces. It is hoped that by inviting other practitioners and allies into my process this document will generate constructive dialogue around queer pedagogy and its fluid performance. Furthermore, this document aims to serve as a reference for future practitioners that work with queer youth and in queer spaces.Theatre and Danc

The Long Goodbye

Senior Project submitted to The Division of Arts of Bard College

Temperature Cable Load Comparison Between Model And Full-Scale Grain Bins

The vertical frictional loads imposed by wheat on five different temperature cables in a model and full-scale bin were measured. tests were conducted to determine the influence of radical positioning of the cable, grain discharge rate, and surface characteristics on the vertical frictional loads. qualitative and quantitative comparisons were made between the model and full-scale temperature cable loads. a scale factor was developed by a similitude analysis and was statistically verified by data

Fasting Insulin Level Is Positively Associated With Incidence of Hypertension Among American Young Adults

OBJECTIVE Although hyperinsulinemia, a surrogate of insulin resistance, may play a role in the pathogenesis of hypertension (HTN), the longitudinal association between fasting insulin level and HTN development is still controversial. We examined the relation between fasting insulin and incidence of HTN in a large prospective cohort. RESEARCH DESIGN AND METHODS A prospective cohort of 3,413 Americans, aged 18?30 years, without HTN in 1985 (baseline) were enrolled. Six follow-ups were conducted in 1987, 1990, 1992, 1995, 2000, and 2005. Fasting insulin and glucose levels were assessed by a radioimmunoassay and hexokinase method, respectively. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% CIs of incident HTN (defined as the initiation of antihypertensive medication, systolic blood pressure ?140 mmHg, or diastolic blood pressure ?90 mmHg). RESULTS During the 20-year follow-up, 796 incident cases were identified. After adjustment for potential confounders, participants in the highest quartile of insulin levels had a significantly higher incidence of HTN (HR 1.85 [95% CI 1.42?2.40]; Ptrend \u3c 0.001) compared with those in the lowest quartile. The positive association persisted in each sex/ethnicity/weight status subgroup. A similar dose-response relation was observed when insulin-to-glucose ratio or homeostatic model assessment of insulin resistance was used as exposure. CONCLUSIONS Fasting serum insulin levels or hyperinsulinemia in young adulthood was positively associated with incidence of HTN later in life for both men and women, African Americans and Caucasians, and those with normal weight and overweight. Our findings suggested that fasting insulin ascertainment may help clinicians identify those at high risk of HTN

Crumpling a Thin Sheet

Crumpled sheets have a surprisingly large resistance to further compression. We have studied the crumpling of thin sheets of Mylar under different loading conditions. When placed under a fixed compressive force, the size of a crumpled material decreases logarithmically in time for periods up to three weeks. We also find hysteretic behavior when measuring the compression as a function of applied force. By using a pre-treating protocol, we control this hysteresis and find reproducible scaling behavior for the size of the crumpled material as a function of the applied force.Comment: revtex 4 pages, 6 eps figures submitted to Phys Rev. let

Development of an Electrostatic Precipitator to Remove Martian Atmospheric Dust from ISRU Gas Intakes During Planetary Exploration Missions

Manned exploration missions to Mars will need dependable in situ resource utilization (ISRU) for the production of oxygen and other commodities. One of these resources is the Martian atmosphere itself, which is composed of carbon dioxide (95.3%), nitrogen (2.7%), argon (1.6%), oxygen (0.13%), carbon monoxide (0.07%), and water vapor (0.03%), as well as other trace gases. However, the Martian atmosphere also contains relatively large amounts of dust, uploaded by frequent dust devils and high Winds. To make this gas usable for oxygen extraction in specialized chambers requires the removal of most of the dust. An electrostatic precipitator (ESP) system is an obvious choice. But with an atmospheric pressure just one-hundredth of Earth's, electrical breakdown at low voltages makes the implementation of the electrostatic precipitator technology very challenging. Ion mobility, drag forces, dust particle charging, and migration velocity are also affected because the low gas pressure results in molecular mean free paths that are approximately one hundred times longer than those at Earth .atmospheric pressure. We report here on our efforts to develop this technology at the Kennedy Space Center, using gases with approximately the same composition as the Martian atmosphere in a vacuum chamber at 9 mbars, the atmospheric pressure on Mars. We also present I-V curves and large particle charging data for various versions of wire-cylinder and rod-cylinder geometry ESPs. Preliminary results suggest that use of an ESP for dust collection on Mars may be feasible, but further testing with Martian dust simulant is required