112 research outputs found

    The Grand Gleaners Project Analysis

    Get PDF
    The Heartside Gleaning Initiative (HGI) is a Grand Rapids based non-profit organization that collects unsold produce from the city’s two farmers markets and distributes it to the low-income residents of the Heartside Neighborhood. Through their efforts they increase access to healthy and local foods as well as combat food waste in the Heartside Community. Seeing the value of this work, we, an interdisciplinary team of Grand Valley State University students, sought to further the mission of the HGI by focusing predominantly on two vital aspects of any non-profit business: promoting and funding. In the winter semester of 2015 we established three courses of action. Our first course of action was to create a crowdfunding “how-to” guide for the HGI. By illustrating how to proficiently utilize crowdfunding platforms this “how-to” guide will also aid other nonprofits. Our second course of action was to develop a storyboard intended to be used in the creation of a short promotional video for the HGI. Finally, we contacted local film professionals to aid HGI in completing a promotional video during its 2015 gleaning season. It is our hope that these efforts will increase the exposure for the Heartside Gleaning Initiative and provide them with the tools to efficiently utilize this exposure

    Band-edge absorption characteristics of semi-insulating indium phosphide under unified Franz-Keldysh and Einstein models

    Get PDF
    The foundational Franz-Keldysh effect and Einstein model are applied in this work to characterize semiconductor band-edge absorption—and its departures from ideality. We unify the Franz-Keldysh and Einstein models to fully characterize the field-induced tunneling of photoexcited electrons from degenerate valence bands into the conduction band, with encroachment into the band gap arising as an Urbach tail. Our unified model is implemented for semi-insulating indium phosphide (SI-InP) with strong agreement seen between the theoretical and experimental results for varied photon energies and electric fields

    Pre-distortion adaptive optics for optical feeder links: simulations and performance analyses

    Get PDF
    Optical feeder links offer immense utility in meeting future communication demands—however, atmospheric turbulence limits their performance. This work targets this challenge through analyses of a bidirectional free-space optical communication (FSOC) link that incorporates pre-distortion adaptive optics (AO) between the next-generation optical ground station at the German Aerospace Center (DLR) Oberpfaffenhofen and the laser communications terminal on Alphasat—a satellite in geostationary orbit (GEO). The analyses are performed via end-to-end Monte Carlo simulations that provide realistic performance estimates of the bidirectional FSOC link for a GEO feeder link scenario. We find that applying pre-distortion AO reduces the total uplink losses of the bidirectional FSOC link by up to 10 dB and lessens the scintillation at the GEO satellite by an order of magnitude. Moreover, applying pre-distortion AO eases the link budget requirements needed for maintaining 99.9% link uptime by as much as 20-40 dB, while its use with a laser guide star shows an additional performance improvement of up to 8 dB. These findings demonstrate the desirability and feasibility of utilizing pre-distortion AO for the realization of optical feeder links

    Reproducibility of the NEPTUNE descriptor-based scoring system on whole-slide images and histologic and ultrastructural digital images

    Get PDF
    The multicenter Nephrotic Syndrome Study Network (NEPTUNE) digital pathology scoring system employs a novel and comprehensive methodology to document pathologic features from whole-slide images, immunofluorescence and ultrastructural digital images. To estimate inter- and intra-reader concordance of this descriptor-based approach, data from 12 pathologists (eight NEPTUNE and four non-NEPTUNE) with experience from training to 30 years were collected. A descriptor reference manual was generated and a webinar-based protocol for consensus/cross-training implemented. Intra-reader concordance for 51 glomerular descriptors was evaluated on jpeg images by seven NEPTUNE pathologists scoring 131 glomeruli three times (Tests I, II, and III), each test following a consensus webinar review. Inter-reader concordance of glomerular descriptors was evaluated in 315 glomeruli by all pathologists; interstitial fibrosis and tubular atrophy (244 cases, whole-slide images) and four ultrastructural podocyte descriptors (178 cases, jpeg images) were evaluated once by six and five pathologists, respectively. Cohen’s kappa for inter-reader concordance for 48/51 glomerular descriptors with sufficient observations was moderate (0.40<kappa ≤0.60) for 17 and good (0.60<kappa ≤0.80) for 8, for 52% with moderate or better kappas. Clustering of glomerular descriptors based on similar pathologic features improved concordance. Concordance was independent of years of experience, and increased with webinar cross-training. Excellent concordance was achieved for interstitial fibrosis and tubular atrophy. Moderate-to-excellent concordance was achieved for all ultrastructural podocyte descriptors, with good-to-excellent concordance for descriptors commonly used in clinical practice, foot process effacement, and microvillous transformation. NEPTUNE digital pathology scoring system enables novel morphologic profiling of renal structures. For all histologic and ultrastructural descriptors tested with sufficient observations, moderate-to-excellent concordance was seen for 31/54 (57%). Descriptors not sufficiently represented will require further testing. This study proffers the NEPTUNE digital pathology scoring system as a model for standardization of renal biopsy interpretation extendable outside the NEPTUNE consortium, enabling international collaborations

    Clinical Characteristics and Treatment Patterns of Children and Adults With IgA Nephropathy or IgA Vasculitis: Findings From the CureGN Study

    Get PDF
    Introduction: The Cure Glomerulonephropathy Network (CureGN) is a 66-center longitudinal observational study of patients with biopsy-confirmed minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy (IgAN), including IgA vasculitis (IgAV). This study describes the clinical characteristics and treatment patterns in the IgA cohort, including comparisons between IgAN versus IgAV and adult versus pediatric patients. Methods: Patients with a diagnostic kidney biopsy within 5 years of screening were eligible to join CureGN. This is a descriptive analysis of clinical and treatment data collected at the time of enrollment. Results: A total of 667 patients (506 IgAN, 161 IgAV) constitute the IgAN/IgAV cohort (382 adults, 285 children). At biopsy, those with IgAV were younger (13.0 years vs. 29.6 years, P < 0.001), more frequently white (89.7% vs. 78.9%, P = 0.003), had a higher estimated glomerular filtration rate (103.5 vs. 70.6 ml/min per 1.73 m2, P < 0.001), and lower serum albumin (3.4 vs. 3.8 g/dl, P < 0.001) than those with IgAN. Adult and pediatric individuals with IgAV were more likely than those with IgAN to have been treated with immunosuppressive therapy at or prior to enrollment (79.5% vs. 54.0%, P < 0.001). Conclusion: This report highlights clinical differences between IgAV and IgAN and between children and adults with these diagnoses. We identified differences in treatment with immunosuppressive therapies by disease type. This description of baseline characteristics will serve as a foundation for future CureGN studies

    Terahertz time-domain spectroscopy for ultrafast and quasi-static characterizations of germanium

    No full text
    In this work, we carry out a comprehensive study of charge carrier dynamics in germanium spanning its ultrafast to quasi-static timescales. The study makes use of a continuous-wave (CW) near-infrared (NIR) pump and terahertz (THz) probe beams to realize a CW NIR pumped THz-time-domain spectroscopy (THz-TDS) system with frequency-selective homodyne detection. This enables characterizations of ultrafast charge carrier scattering, while the detection is locked to the THz probe beam, and quasi-static charge carrier recombination, while the detection is locked to the CW NIR pump beam. The ultrafast THz-TDS characterization reveals scatter times of 239 fs for electrons and 204 fs for holes at low pump intensities, which reduce to scatter times of 186 fs for electrons and 159 fs for holes at higher pump intensities. These scatter times give good agreement to the literature mobility of germanium at low intensities and indicate carrier-carrier scattering at higher intensities. The quasi-static THz-TDS characterization suggests that the charge carrier lifetime is dominated by surface states. The manifestation of surface states is gleaned by characterizing germanium samples with varying forms of microhole arrays. This reveals lifetimes ranging from 1.5 to 8.6 ÎĽs, in good agreement with a linearized model with a surface recombination velocity of 14 200 cm/s. Ultimately, the experimental results from the CW NIR pump THz-TDS system and the applied theoretical models give an accurate depiction of the charge carrier dynamics that evolve in germanium over its ultrafast to quasi-static timescales.Applied Science, Faculty ofEngineering, School of (Okanagan)ReviewedFacult

    Generated Value of Electricity Versus Incurred Cost for Solar Arrays under Conditions of High Solar Penetration

    No full text
    This work considers an emerging value-based paradigm for solar generation under high penetration, in light of its conflicting cycles of supply and demand. The resulting swings in electricity prices, in locales such as California, call into question the aim of optimizing solar arrays solely in terms of accumulated electrical power. Thus, this work studies solar arrays in terms of value, as an accumulated product of electrical power and price, where solar arrays that generate greater electrical power over more profitable early- and late-day hours yield improved value. Experimental, theoretical, and economic analyses are given to characterize the industry-standard angled-panel, an alternative V-groove, and a new U-groove array over a 5-year study. The trends and projections suggest that the industry-standard angled-panel array realizes the best value-based performance at present, although it will likely be outperformed in the foreseeable future by the V-groove array.Applied Science, Faculty ofEngineering, School of (Okanagan)ReviewedFacult

    Performance bounds for diversity receptions over a new fading model with arbitrary branch correlation

    No full text
    The performance of a new (Beaulieu-Xie) fading model is analyzed using bounds. This recently proposed fading model can be used to describe both line-of-sight and non-line-of-sight components of a fading channel having different diversity orders. We consider the outage probability and error rate performance of maximal ratio combining, equal-gain combining, and selection combining over arbitrarily correlated Beaulieu-Xie fading channels. Closed-form expressions for upper and lower bounds to the outage probability and error rate are obtained, and it is shown that these bounds are asymptotically tight in the high signal-to-noise ratio regime. The analytical results are verified via Monte Carlo simulations. It is shown that the Beaulieu-Xie fading model can be more useful than the Ricean and Nakagami-m fading models in characterizing environments with both line-of-sight and multiple reflected specular components.Applied Science, Faculty ofEngineering, School of (Okanagan)ReviewedFacult
    • …
    corecore