Breeding Ecology of the Mountain Plover (Charadrius montanus) in Phillips County, Montana

Reproduction is a central aspect of an organism\u27s ecology and life history. Understanding a species’ reproductive ecology is critical to informing any conservation or management actions. Using data from a population of Mountain Plovers (Charadrius montanus) in Phillips County, Montana, I introduce a general, model-based approach to estimating nest detection probability based on individual, group, environmental and temporal covariates. I found nest detection probability in Mountain Plovers was influenced by nest initiation date, breeding area size, day of season, nest age, observer experience level, nest fate, daily high temperature and daily precipitation. Single-visit detection probability ranged from \u3c0.10 to \u3e0.80, clearly demonstrating the need for a model-based approach that accounts for individual heterogeneity. I analyzed the spatial patterning of Mountain Plover nests on Black-Tailed Prairie Dog (Cynomys ludovicianus) colonies and attempted to link spatial characteristics of nests to nest survival. I found that nests were more dispersed at small spatial scales (\u3c200 m) than would be expected under complete spatial randomness and that male-tended nests were more isolated than female-tended nests but that nest placement had no significant effect on daily nest survival. I analyzed the survival of dependent Mountain Plover chicks from hatch to fledging using resighting data of marked adults. My best model included effects of chick age, day of season, daily temperature, and daily precipitation. However, this model did not predict chick survival with good precision. Collectively, these results advance our understanding of avian breeding ecology in general and the Mountain Plover in particular

Towards Colloidal Self-Assembly for Functional Materials

Nanostructuring has led to materials with novel and improved materials properties driving innovation across fields as varied as transportation, computing, energy and biotechnology. However, the benefits of nanostructured material have not widely been extended into large-scale, three-dimensional applications as deterministic pattern techniques have proven too expensive for devices outside of high value products. This thesis explores how colloidal self-assembly can be used to form macroscopic functional materials with short-range order for electronic, photonic and electrochemical applications at scale. DNA-functionalized nanoparticles are versatile models for exploring colloidal self-assembly due to the highly specific, tunable and thermally reversible binding between DNA strands. Gold nanoparticles coated with DNA were used to investigate the temperature-dependent interaction potentials and the gel formation in DNA-colloidal systems. The electronic conductivity and the plasmonic response of the DNA-gold gels were studied to explore their applicability as porous electrodes and SERS substrates, respectively. Subsequently, silica nanoparticles were assembled into nanostructures that preferentially scatter blue light using both DNA and polymer-colloid interactions. Finally, rod-sphere structures made from DNA-coated gold nanoparticles and viruses were explored, demonstrating how high-aspect ratio building blocks can create composite structures with increased porosity. The gold-virus gel structures inspired the design and assembly of a silicon-carbon nanotube composite material using covalent bonds that shows promise for high energy density anodes

Photonic bandgap fibers for transmitting high peak-power pulses in the near infrared

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2010.Includes bibliographical references (p. [41-42]).Hollow-core photonic bandgap fibers (PBG) offer the opportunity to suppress highly the optical absorption and nonlinearities of their constituent materials, which makes them viable candidates for transmitting high-peak power pulses. This thesis demonstrates the fabrication and characterization of polymer-composite PBG fibers in a novel materials system, polycarbonate and arsenic sulfide glass. Propagation losses for the 60pm-core fibers are less than 2dB/m, a 52x improvement over previous PBG fibers at this wavelength. Through preferential coupling the fiber is capable of operating with over 97% the fiber's power output in the fundamental (HE,,) mode. The fiber transmitted pulses with peak powers of 11.4 MW before failure.by Zachary Ruff.S.M

STEM Education: Attracting and Retaining Female Students in Secondary STEM programs

This narrative case study examines a high achieving STEM based high school and its ability to attract, retains, and engage female students. Given the recent importance placed on STEM graduates and STEM careers it is important for schools to understand how they can engage traditionally underserved minorities in STEM fields. The research used a series of semi-structured interviews in an attempt to understand the point of view of the female student participants to try to comprehend the factors that allowed one school to not only attract female students to its program, but also to retain them and keep them engaged throughout their education.Ed.D., Educational Leadership and Management -- Drexel University, 201

Hygiene in the United States Brow Shaping Industry: A Benchmarking Report

Purpose: To provide a current benchmark of hand hygiene and brow cleansing in the brow shaping industry across the United States of America. Background: Brow abscesses have been linked to the microtrauma associated with brow shaping. This paper provides an understanding of normative standards of hand hygiene and brow cleansing in the brow shaping industry at both the regional and national levels. Methods: This project involved a phone survey of 255 brow salons across the United States – 5 from the most populous city in every state and Washington, D.C. Uni- and multivariate associations between regional and national brow hygiene practices were explored using chi-square testing and multinomial logistic regression modeling. Results: Of 255 brow salons included in this study, 137 performed waxing (54%), 72 performed threading (28%) and 46 performed both (18%). Hand hygiene was required at 97% of brow salons, most commonly using alcohol-based sanitizer (59%), hand washing (22%), or some combination of the two (16%). Brow cleansing was required at 80% of salons, with the vast majority using an alcohol-based cleanser (75%). Multinomial logistic regression analysis of hand and brow hygiene methods, including hand hygiene frequency and service type, failed to show regionally predictive differences. Hand hygiene was performed more routinely than brow hygiene nationwide (p\u3c0.01). Conclusions: The brow shaping industry is performing hand hygiene nearly across the board, but would benefit from increased rates of brow cleansing

Reliability of Unilateral Isometric and Dynamic Leg Press Force and Power

Strength and power are critical components of athletic performance. Athletes commonly perform sport-specific movements off a single leg, but there are few reliable, easily administered unilateral leg force and power assessments. PURPOSE: To determine 1) the reliability of unilateral leg press maximal isometric force (MIF) and peak power tests and 2) the percentage of MIF that elicits unilateral peak power during a dynamic throw. We hypothesized that the tests would be reliable for the assessment of unilateral MIF and peak power and that unilateral peak power would be achieved at 50% of MIF. METHODS: Eighteen apparently healthy, recreationally active adults (17M: 1F; 27.4 ± 5.0 years; 1.78 ± 0.01 m; 93.5 ± 22.5 kg; 3159 ± 807 N bilateral MIF) completed three testing sessions. After a brief standardized warm-up, each subject performed three maximal unilateral isometric leg presses (MIF) with each leg at 90° of knee flexion on a modified leg press sled equipped with a force plate, linear encoder, and magnetic brake. Subsequently, the sled was unlocked and loaded in ascending fashion with 30%, 40%, 50%, 60%, and 70% of MIF; with an initial knee angle of 90°, subjects used maximal effort to throw each load twice, unilaterally, with each leg. Subjects rested and reset for 10-30 s between efforts. Data were sampled at 300 Hz, low pass filtered at 4 Hz, and peak instantaneous power (W) was calculated for each throw using the measured sled force and velocity. Intraclass correlation coefficients (ICC) were computed for the highest force and power repetition at each load across the three sessions. The ICC (95% CI) and peak power output were determined for both right and left legs. ICCs were considered excellent if ≥ 0.95, high if ≥ 0.90, good if ≥ 0.80, fair if ≥ 0.70, poor if ≤ 0.70, and very poor if ≤ 0.40. RESULTS: MIF showed good reliability between sessions [ICC: 0.85 (0.62, 0.94; left leg); 0.86 (0.58, 0.95; right leg)]. Unilateral peak power also showed good to high reliability between sessions across all loads: ICC (left leg) 30%: 0.91 (0.81, 0.96); 40%: 0.91 (0.81, 0.96); 50%: 0.95 (0.88, 0.98); 60%: 0.93 (0.86, 0.97); 70%: 0.81 (0.64, 0.92); (right leg) 30%: 0.95 (0.89, 0.98); 40%: 0.94 (0.87, 0.97); 50%: 0.92 (0.84, 0.97); 60%: 0.92 (0.84, 0.97); 70%: 0.90 (0.80, 0.96). Across all three sessions, peak power by the left leg was achieved at: 30% (11 of 18 participants); 40% (6 of 18); 50% (1 of 18). Peak power by the right leg was achieved at: 30% (13 of 18 participants); 40% (4 of 18); 50% (1 of 18). CONCLUSION: Unilateral leg press MIF and peak power can be reliably assessed with a modified leg press equipped with a force plate, linear encoder, and magnetic brake in a recreationally active population. Sport teams and coaches can use single leg isometric presses and throws as reliable methods to test their athletes’ unilateral force and peak power, respectively, with loads of 30-50% MIF appropriate for peak power measurement

Role of salt concentration in stabilizing charged Ni-rich cathode interfaces in Li-ion batteries

The cathode–electrolyte interphase (CEI) in Li-ion batteries plays a key role in suppressing undesired side reactions while facilitating Li-ion transport. Ni-rich layered cathode materials offer improved energy densities, but their high interfacial reactivities can negatively impact the cycle life and rate performance. Here we investigate the role of electrolyte salt concentration, specifically LiPF6 (0.5–5 m), in altering the interfacial reactivity of charged LiN0.8Mn0.1Co0.1O2 (NMC811) cathodes in standard carbonate-based electrolytes (EC/EMC vol %/vol % 3:7). Extended potential holds of NMC811/Li4Ti5O12 (LTO) cells reveal that the parasitic electrolyte oxidation currents observed are strongly dependent on the electrolyte salt concentration. X-ray photoelectron and absorption spectroscopy (XPS/XAS) reveal that a thicker LixPOyFz-/LiF-rich CEI is formed in the higher concentration electrolytes. This suppresses reactions with solvent molecules resulting in a thinner, or less-dense, reduced surface layer (RSL) with lower charge transfer resistance and lower oxidation currents at high potentials. The thicker CEI also limits access of acidic species to the RSL suppressing transition-metal dissolution into the electrolyte, as confirmed by nuclear magnetic resonance (NMR) spectroscopy and inductively coupled plasma optical emission spectroscopy (ICP-OES). This provides insight into the main degradation processes occurring at Ni-rich cathode interfaces in contact with carbonate-based electrolytes and how electrolyte formulation can help to mitigate these

Homelessness Assessment of the Mountain West, 2023

This fact sheet examines 2023 homelessness assessment data from the U.S. Department of Housing and Urban Development for five Mountain West states: Arizona, Colorado, Nevada, New Mexico, and Utah

Understanding improved capacity retention at 4.3 V in modified single crystal Ni-rich NMC//graphite pouch cells at elevated temperature

The capacity retention of commercially-sourced pouch cells with single crystal Al surface-doped Ni-rich cathodes (LiNi0.834Mn0.095Co0.071O2) is examined. The degradation-induced capacity fade becomes more pronounced as the upper-cut-off voltage (UCV) increases from 4.2 V to 4.3 V (vs. graphite) at a fixed cycling temperature (either 25 or 40 °C). However, cycles with 4.3 V UCV (slightly below the oxygen loss onset) show better capacity retention upon increasing the cycling temperature from 25 °C to 40 °C. Namely, after 500 cycles at 4.3 V UCV, cycling temperature at 40 °C retains 85.5% of the initial capacity while cycling at 25 °C shows 75.0% capacity retention. By employing a suite of electrochemical, X-ray spectroscopy and secondary ion mass spectrometry techniques, we attribute the temperature-induced improvement of the capacity retention at high UCV to the combined effects of Al surface-dopants, electrochemically resilient single crystal Ni-rich particles, and thermally-improved Li kinetics translating into better electrochemical performance. If cycling remains below the lattice oxygen loss onset, improved capacity retention in industrial cells should be achieved in single crystal Ni-rich cathodes with the appropriate choice of cycling parameter, particle quality, and particle surface dopants

The Complex Role of Aluminium Contamination in Nickel-Rich Layered Oxide Cathodes for Lithium-Ion Batteries

A major challenge for lithium-ion batteries based on nickel-rich layered oxide cathodes is capacity fading. While chemo-mechanical degradation and/or structural transformation are widely considered responsible for degradation, a comprehensive understanding of this process is still not complete. For the stable performance of these cathode materials, aluminium (Al) plays a crucial role, not only as a current collector but also as substitutional element for the transition metals in the cathodes and a protective oxide coating (as Al2O3). However, excess Al can be detrimental due to both its redox inactive nature in the cathode and the insulating nature of Al2O3. In this work, we report an analysis of the Al content in two different types of nickel-rich manganese cobalt oxide cathode materials after battery cycling. Our results indicate a significant thickening of Al-containing phases on the surface of the NMC811 electrode. Similar results are observed from commercial batteries (a mixture of NMC532 and LiMn2O4) that were analysed before use and at the end of life, where Al-containing phases were found to increase significantly at surfaces and grain boundaries. Considering the detrimental effects of the excess Al in the nickel-rich cathodes, our observation of increased Al content via battery cycling is believed to bring a new perspective to the ongoing discussions regarding the capacity fading phenomenon of nickel-rich layered oxide materials as part of their complex degradation mechanisms